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Examen Estatal de Imagenología - independent subject foundations study materials
Examen Estatal de Imagenología - independent subject foundations study resources

Examen Estatal de Imagenología - independent subject foundations practice questions

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Question 1Neuroimaging, spinal anatomy and diagnostic reasoning

A 66-year-old male arrives at the emergency department 2 hours after acute onset of right hemiplegia and global aphasia. Emergency non-contrast head CT is performed to evaluate for ischemic stroke. The radiologist calculates the Alberta Stroke Program Early CT Score (ASPECTS). Loss of gray-white matter differentiation is identified in the insular ribbon, lentiform nucleus, and M2 cortical region. What is the patient's ASPECTS score?

  1. 10
  2. 7 Correct answer.
  3. 5
  4. 3

Explanation

The ASPECTS score is a 10-point quantitative topographical CT score for middle cerebral artery (MCA) stroke. Starting from a normal score of 10, one point is subtracted for each defined anatomical area showing early ischemic changes (loss of gray-white differentiation, hypoattenuation). With three involved areas (insular ribbon, lentiform nucleus, M2), the score is 10 - 3 = 7. A score >= 6 is favorable for endovascular thrombectomy.

Question 2Neuroimaging, spinal anatomy and diagnostic reasoning

An unenhanced head CT performed within 90 minutes of acute stroke onset demonstrates spontaneous hyperattenuation of the horizontal M1 segment of the right middle cerebral artery compared to the contralateral side and adjacent brain parenchyma, without parenchymal hemorrhage. What is this crucial early vascular sign called?

  1. Insular ribbon sign
  2. Cord sign of dural sinus thrombosis
  3. Hyperdense middle cerebral artery (MCA) sign Correct answer.
  4. Dense basilar artery sign

Explanation

The 'hyperdense MCA sign' is caused by acute thromboembolic occlusion of the horizontal M1 segment of the middle cerebral artery. The high attenuation (typically > 60-80 HU) is produced by high packed red blood cell and fibrin content within the acute stationary intraluminal thrombus, representing an early marker of large-vessel occlusion.

Question 3Neuroimaging, spinal anatomy and diagnostic reasoning

A 58-year-old male with long-standing poorly controlled arterial hypertension presents with acute headache, nausea, and contralateral dense hemiplegia. An emergent non-contrast head CT demonstrates an acute, homogeneous, hyperdense parenchymal hematoma (measuring 65 to 80 HU) with surrounding hypodense vasogenic edema and local mass effect. What is the most common anatomical site for spontaneous hypertensive intracerebral hemorrhage?

  1. Subcortical lobar frontal white matter
  2. Centrum semiovale
  3. Midbrain tegmentum
  4. Basal ganglia (specifically the putamen and internal capsule) Correct answer.

Explanation

The basal ganglia-predominantly the putamen (50-60%) and thalamus (15-20%)-is the most common anatomical site of spontaneous hypertensive intracerebral hemorrhage. It results from rupture of lipohyalinotic Charcot-Bouchard microaneurysms along the deep lenticulostriate penetrating branches of the middle cerebral artery.

Question 4Neuroimaging, spinal anatomy and diagnostic reasoning

A 21-year-old male sustains head trauma in a boxing match followed by a lucid interval and subsequent rapid neurological deterioration. Non-contrast head CT reveals a hyperdense, biconvex (lentiform) extra-axial collection along the right temporoparietal convexity that does not cross cranial sutures but displaces the dural venous sinus. What is the diagnosis and injured vessel?

  1. Acute subdural hematoma caused by rupture of cortical bridging veins
  2. Acute epidural hematoma caused by laceration of the middle meningeal artery Correct answer.
  3. Chronic subdural hygroma caused by arachnoid membrane tear
  4. Subarachnoid hemorrhage caused by anterior communicating artery aneurysm

Explanation

An acute epidural (extradural) hematoma is classically caused by temporal bone fracture lacerating the middle meningeal artery or its branches. The blood accumulates in the potential space between the inner table of the skull and the periosteal dura mater, forming a high-pressure biconvex (lentiform) collection that is confined by cranial sutures where the dura is tightly attached.

Question 5Neuroimaging, spinal anatomy and diagnostic reasoning

A 52-year-old female presents with progressive focal headaches. Contrast-enhanced brain MRI demonstrates a broad-based, extra-axial, dural-attached mass along the sphenoid ridge. The mass is isointense to cortex on T1 and T2 sequences, enhances vividly and homogeneously with gadolinium, exhibits a tapering peripheral rim of dural enhancement ('dural tail sign'), and induces adjacent hyperostosis of the overlying skull. What is the diagnosis?

  1. Metastatic breast adenocarcinoma to the skull vault
  2. Acoustic vestibular schwannoma
  3. Dural arteriovenous fistula
  4. Benign intracranial meningioma Correct answer.

Explanation

Meningiomas are the most common extra-axial intracranial neoplasms in adults. Classic features include a broad dural base, homogeneous and vivid contrast enhancement, adjacent hyperostosis or reactive bone remodeling, a CSF or vascular cleft separating it from brain parenchyma, and the classic 'dural tail sign' representing reactive dural thickening.

Question 6Neuroimaging, spinal anatomy and diagnostic reasoning

A 60-year-old male with treated bronchogenic adenocarcinoma develops confusion and ataxia. Contrast-enhanced brain MRI reveals multiple, well-circumscribed, round, enhancing nodules located specifically at the corticomedullary (gray-white matter) junctions of both cerebral hemispheres, associated with disproportionately severe, finger-like vasogenic edema in the deep white matter. Which pathophysiology explains this characteristic anatomical distribution?

  1. Embolic hematogenous tumor seeding trapped within the microvasculature at the junction where vessel caliber abruptly narrows Correct answer.
  2. Retrograde perineural tumor extension along the olfactory nerve branches
  3. Direct trans-ependymal cerebrospinal fluid seeding through the ventricles
  4. Local microglial transformation triggered by systemic paraneoplastic antibodies

Explanation

Hematogenous cerebral metastases lodge predominantly at the corticomedullary junction because penetrating arterial vessels undergo an abrupt reduction in caliber at the transition between gray and white matter, functioning as a microvascular filter that traps circulating tumor emboli. Disproportionate vasogenic edema results from tumor-secreted VEGF disrupting the blood-brain barrier.

Question 7Neuroimaging, spinal anatomy and diagnostic reasoning

A 28-year-old male presents with adult-onset focal epilepsy. High-resolution brain MRI demonstrates a 6 mm unilocular cystic lesion in the parietal cortex with CSF-like signal intensity on T1 and T2 sequences. Within the cyst, a 1 mm eccentric, hyperintense mural nodule representing the invaginated scolex ('hole-with-a-dot' sign) is clearly visualized, without surrounding edema or capsule enhancement. According to the Escobar classification of neurocysticercosis, which stage is this?

  1. Granular-nodular stage
  2. Vesicular stage (viable cyst) Correct answer.
  3. Colloidal vesicular stage
  4. Nodular calcified stage

Explanation

In neurocysticercosis (Taenia solium), the vesicular stage represents viable larval cysts. The cyst fluid is clear (matching CSF), the wall is thin and non-enhancing, and the eccentric invaginated scolex appears as a discrete internal nodule ('hole-with-a-dot' sign). Host immune tolerance prevents surrounding edema during this stage.

Question 8Neuroimaging, spinal anatomy and diagnostic reasoning

A 29-year-old female presents with acute unilateral optic neuritis, followed 8 months later by sensory ataxia. Brain MRI demonstrates multiple ovoid T2/FLAIR hyperintense demyelinating plaques oriented perpendicular to the lateral ventricles along subependymal venules ('Dawson fingers'), in addition to juxtacortical, infratentorial, and cervical spinal cord lesions. Which disease does this imaging pattern definitively indicate?

  1. Multiple sclerosis (esclerosis múltiple) Correct answer.
  2. Neuromyelitis optica spectrum disorder (NMOSD)
  3. Acute disseminated encephalomyelitis (ADEM)
  4. Cerebral autosomal dominant arteriopathy (CADASIL)

Explanation

'Dawson fingers' are classic imaging features of multiple sclerosis on sagittal T2/FLAIR MRI, caused by perivenular demyelination extending radially perpendicular to the lateral ventricles. Combined with typical lesions in juxtacortical, infratentorial, and spinal cord locations, they fulfill the McDonald imaging criteria for dissemination in space.

Question 9Neuroimaging, spinal anatomy and diagnostic reasoning

A 32-year-old diver hits his head on the seabed following a shallow dive. Axial cervical spine CT demonstrates bilateral fractures through both the anterior and posterior arches of the atlas (C1 vertebra), with lateral displacement of the lateral masses of C1 relative to the articular pillars of C2 exceeding a combined total of 7 mm on coronal reformations (Spence rule). What is the specific eponym for this cervical spine burst fracture?

  1. Hangman's fracture of C2
  2. Clay-shoveler fracture of C7
  3. Jefferson burst fracture of C1 Correct answer.
  4. Chance distraction fracture

Explanation

A Jefferson fracture is a burst fracture of the atlas (C1) caused by severe axial loading driving the occipital condyles into the lateral masses. It classically produces a four-part fracture involving both the anterior and posterior arches. A combined lateral displacement of C1 lateral masses > 7 mm signifies rupture of the transverse atlantal ligament, establishing mechanical instability.

Question 10Thoracic and cardiovascular imaging patterns

A 42-year-old male evaluated within Cuba's Programa Nacional de Control de la Tuberculosis presents with chronic cough, night sweats, and weight loss. A posteroanterior chest radiograph reveals an apical cavitary lesion with thick, irregular walls in the right upper lobe, associated with adjacent micronodular and fibrotic opacities. Which radiological feature most strongly supports active post-primary pulmonary tuberculosis?

  1. Homogeneous basilar consolidation with air bronchograms and blunting of the costophrenic angle
  2. A thin-walled round radiolucency with an internal mobile dependent mass and air-crescent sign
  3. Thick-walled cavitary lesions located in the apical and posterior segments of the upper lobes with endobronchial tree-in-bud satellite opacities Correct answer.
  4. Diffuse bilateral symmetric interstitial reticular opacities with predominant honeycombing in the lung bases

Explanation

Post-primary (reactivation) pulmonary tuberculosis typically involves the apical and posterior segments of the upper lobes or the superior segment of the lower lobes. Active disease is characterized by thick-walled cavitation accompanied by bronchogenic dissemination manifesting as centrilobular nodules and branching 'tree-in-bud' opacities on imaging, consistent with MINSAP tuberculosis surveillance guidelines.

Question 11Thoracic and cardiovascular imaging patterns

A 35-year-old female presents with sudden high fever, pleuritic chest pain, and rust-colored sputum. Chest radiography reveals homogeneous opacification of the right middle lobe with crisp inferior margination along the major fissure and sharp superior margination along the minor fissure. The right heart border is obscured on the frontal view. What radiological sign does this border obscuration represent?

  1. Golden S sign of Golden
  2. Westermark sign
  3. Cervicothoracic sign
  4. Silhouette sign of Felson Correct answer.

Explanation

Felson's silhouette sign occurs when two structures of the same radiographic density are in direct anatomical contact, obliterating their shared optical margin. Because the right middle lobe anatomically abuts the right atrium, consolidation of the middle lobe silhouettes and obscures the right cardiac border.

Question 12Thoracic and cardiovascular imaging patterns

A 58-year-old post-surgical patient develops sudden dyspnea and tachycardia. Computed tomography pulmonary angiography (CTPA) is performed. Which imaging finding constitutes the direct, definitive diagnostic sign of acute pulmonary embolism?

  1. A complete or partial intraluminal filling defect surrounded by contrast medium forming acute angles with the arterial wall on axial sections Correct answer.
  2. Wedge-shaped peripheral consolidation representing pulmonary infarction with surrounding ground-glass halo
  3. Focal dilatation of the main pulmonary artery trunk exceeding 29 mm without intraluminal filling defects
  4. Abrupt tapering of peripheral segmental vessels with local pleural reaction alone

Explanation

The definitive direct sign of acute pulmonary thromboembolism on contrast-enhanced CTPA is an intraluminal filling defect that is completely occlusive or partially surrounded by contrast material, typically forming acute angles with the vascular wall ('polo-mint' sign in cross section or 'railroad-track' sign on longitudinal views).

Question 13Thoracic and cardiovascular imaging patterns

A 64-year-old heavy smoker presents with hemoptysis. A chest CT reveals a 2.8 cm solitary pulmonary nodule in the left upper lobe. Which morphological feature identified on high-resolution thin-section CT carries the highest positive predictive value for primary bronchogenic carcinoma?

  1. Smooth, round margins with concentric 'target-like' laminated calcification
  2. Corona radiata with fine, radiating spiculation and pleural tagging Correct answer.
  3. Central coarse 'popcorn' calcification with well-defined borders
  4. Extensive internal macroscopic fat attenuation measuring -60 to -100 Hounsfield Units

Explanation

The presence of radiating spiculated margins ('corona radiata') reflects malignant cellular infiltration along adjacent bronchoarterial sheaths, pulmonary septa, and lymphatics, carrying a positive predictive value for malignancy exceeding 90%. Pleural indentation or tagging further increases malignant probability.

Question 14Thoracic and cardiovascular imaging patterns

A 60-year-old male with a 40 pack-year smoking history undergoes high-resolution chest CT (HRCT). The images demonstrate bilateral, non-tapering dilatations of small radiolucent spaces centered around the terminal bronchioles in the upper lobes, with intact surrounding lung parenchyma and thin, barely perceptible walls. Which subtype of emphysema does this describe?

  1. Panlobular (panacinar) emphysema
  2. Paraseptal (distal acinar) emphysema
  3. Centrilobular (centriacinar) emphysema Correct answer.
  4. Cicatricial (irregular) emphysema

Explanation

Centrilobular emphysema is the classic smoking-related emphysema, characterized on HRCT by focal areas of low attenuation centered around the centrilobular core artery within the secondary pulmonary lobule, predominantly affecting the apical and posterior segments of the upper lobes.

Question 15Thoracic and cardiovascular imaging patterns

A 67-year-old male presents with progressive exertional dyspnea and bibasilar end-inspiratory Velcro crackles. Volumetric high-resolution CT (HRCT) of the chest without contrast reveals subpleural, basal-predominant reticular opacities with architectural distortion, traction bronchiectasis, and multilayered subpleural honeycombing, in the absence of micronodules, extensive ground-glass opacity, or mosaic perfusion. Which diagnostic pattern is established?

  1. Definite Non-Specific Interstitial Pneumonia (NSIP)
  2. Cryptogenic Organizing Pneumonia (COP)
  3. Hypersensitivity Pneumonitis (HP) with airway trapping
  4. Definite Usual Interstitial Pneumonia (UIP) pattern Correct answer.

Explanation

Under international and Cuban thoracic consensus guidelines, the presence of subpleural, basilar-predominant reticulation, traction bronchiectasis, and definite honeycombing in the absence of atypical features meets the strict HRCT criteria for a Definite Usual Interstitial Pneumonia (UIP) pattern, obviating the need for surgical lung biopsy in the appropriate clinical context.

Question 16Thoracic and cardiovascular imaging patterns

A 22-year-old trauma victim is maintained in the supine position following a high-speed vehicular collision. An anteroposterior supine bedside chest radiograph is obtained. Which radiological sign indicates the presence of an occult pneumothorax in the supine projection?

  1. Deep sulcus sign with abnormal deepening and radiolucency of the ipsilateral costophrenic angle Correct answer.
  2. Prominent air bronchograms extending to the periphery of the lower lung zone
  3. Elevated hemidiaphragm with ipsilateral mediastinal shift
  4. Homogeneous apical cap opacity with thickening of the apical extrapleural fat

Explanation

In supine patients, intrapleural free air collects anteriorly and basally rather than at the apex. It outlines the anterior costophrenic gutter, producing an abnormally deep, sharp, and hyperlucent costophrenic angle known as the 'deep sulcus sign,' which is a critical sign of occult pneumothorax on supine chest films.

Question 17Thoracic and cardiovascular imaging patterns

A 62-year-old male with long-standing uncontrolled arterial hypertension presents with acute, tearing substernal chest pain radiating to his interscapular region. Contrast-enhanced thoracic CT angiography reveals an intimal flap originating immediately distal to the origin of the left subclavian artery, extending distally along the descending thoracic aorta into the abdominal aorta. What is the correct classification of this condition?

  1. Stanford Type A aortic dissection
  2. Stanford Type B (DeBakey Type III) aortic dissection Correct answer.
  3. Penetrating atherosclerotic ulcer without intramural hematoma
  4. Traumatic aortic pseudoaneurysm of the aortic isthmus

Explanation

Stanford Type B dissections involve exclusively the descending aorta distal to the origin of the left subclavian artery (corresponding to DeBakey Type III), without involvement of the ascending aorta. Stanford Type A dissections involve the ascending aorta and represent surgical emergencies, whereas uncomplicated Type B dissections are primarily managed with rigorous medical hemodynamic control.

Question 18Thoracic and cardiovascular imaging patterns

On an upright posteroanterior chest radiograph, what is the classic radiological finding that represents the accumulation of at least 175 to 200 mL of free pleural fluid in the dependent hemithorax?

  1. Flattening of the ipsilateral hemidiaphragm with contralateral tracheal deviation
  2. Perihilar cuffing with bat-wing alveolar infiltrates
  3. Blunting of the lateral costophrenic angle with a concave-upward fluid curve (meniscus sign) Correct answer.
  4. Triangular retrocardiac opacity silhouetting the left pulmonary artery

Explanation

On an erect frontal chest radiograph, free fluid first accumulates in the posterior costophrenic sulcus (visible at ~50 mL on lateral views) and then fills the lateral costophrenic angle (visible at 175-200 mL), forming a classic homogeneous opacity with a superior concave-upward border known as the meniscus sign.

Question 19Thoracic and cardiovascular imaging patterns

A 48-year-old female presents with bilateral ptosis, diplopia, and progressive muscle fatigue. A contrast-enhanced chest CT reveals a smooth, lobulated, homogeneous soft-tissue mass located in the prevascular (anterior) mediastinum, positioned immediately anterior to the ascending aorta and superior vena cava, with no macroscopic fat or calcification. Which condition is the most likely diagnosis?

  1. Posterior neurogenic schwannoma
  2. Substernal multinodular goiter with colloid cysts
  3. Mature cystic teratoma
  4. Thymoma associated with myasthenia gravis Correct answer.

Explanation

Thymoma is the most common primary tumor of the anterior (prevascular) mediastinum in adults and is strongly associated with myasthenia gravis (present in up to 30-50% of thymoma cases). On CT, it typically appears as a homogeneous, smooth, or lobulated anterior mediastinal soft-tissue mass.

Question 20Thoracic and cardiovascular imaging patterns

A 52-year-old female with a history of recurrent childhood pulmonary infections presents with chronic purulent sputum production and hemoptysis. A high-resolution chest CT (HRCT) demonstrates an internal bronchial luminal diameter substantially exceeding the diameter of its accompanying pulmonary artery branch in the right lower lobe, accompanied by peribronchial wall thickening and lack of peripheral bronchial tapering. Which pathognomonic CT sign does this represent?

  1. Signet ring sign indicative of bronchiectasis Correct answer.
  2. Gloved-finger sign indicative of allergic bronchopulmonary aspergillosis
  3. Crazy-paving pattern indicative of pulmonary alveolar proteinosis
  4. Comet tail sign indicative of round atelectasis

Explanation

The 'signet ring sign' on HRCT is diagnostic of bronchiectasis. The dilated bronchus viewed in cross-section appears as a ring of soft tissue representing the thickened bronchial wall, adjacent to a smaller opacified circular pulmonary arteriole, resembling a signet or pearl ring (bronchoarterial ratio > 1.0 to 1.5).

Question 21Thoracic and cardiovascular imaging patterns

A 40-year-old female with systemic lupus erythematosus presents with dyspnea, orthopnea, and distant heart sounds. A posteroanterior chest radiograph demonstrates marked symmetrical enlargement of the cardiac silhouette with a globular, flask-like or 'water-bottle' contour and sharp margins, without pulmonary venous congestion. What is the most likely diagnosis?

  1. End-stage dilated cardiomyopathy with biventricular failure
  2. Large pericardial effusion Correct answer.
  3. Severe mitral stenosis with giant left atrium
  4. Large mediastinal liposarcoma encasing the great vessels

Explanation

Rapid or massive accumulation of pericardial fluid causes generalized enlargement of the cardiac shadow with smooth, rounded contours and sharp cardiophrenic angles, classic for the 'water-bottle' or flask-shaped heart. The absence of pulmonary congestion helps distinguish simple pericardial effusion from true congestive heart failure.

Question 22Thoracic and cardiovascular imaging patterns

A 28-year-old male is admitted following severe blunt thoracic trauma. Plain chest radiography reveals fractures of three consecutive ribs, each broken in two separate places along the anterolateral arc, accompanied by paradoxical chest wall motion during respiration. What is the definitive radiological and clinical diagnosis?

  1. Simple nondisplaced costal fractures
  2. Unilateral traumatic hemothorax without parenchymal injury
  3. Primary sternal fracture with retrosternal hematoma
  4. Flail chest (tórax batiente) with isolated free chest wall segment Correct answer.

Explanation

Flail chest (tórax batiente in Cuban surgical terminology) is defined by fractures of at least three consecutive ribs in two or more places each, producing a detached, floating thoracic segment that moves paradoxically (inward on inspiration, outward on expiration). It is frequently accompanied by underlying pulmonary contusion.

Question 23Thoracic and cardiovascular imaging patterns

A 50-year-old asymptomatic male undergoes routine chest radiography for pre-employment clearance. A smooth, round, fat-density mass is identified in the anterior cardiophrenic angle on the right side, located adjacent to the anterior chest wall and xiphoid process. What type of congenital diaphragmatic hernia does this finding represent?

  1. Morgagni hernia Correct answer.
  2. Bochdalek hernia
  3. Sliding hiatal hernia
  4. Paraesophageal hiatal hernia

Explanation

Morgagni hernias are congenital diaphragmatic defects occurring anteriorly through the retrosternocostal space (foramen of Morgagni / Larrey's space), 90% of which occur on the right side in the cardiophrenic angle, typically containing omental fat, transverse colon, or liver.

Question 24Thoracic and cardiovascular imaging patterns

A 32-year-old woman presents with erythema nodosum, uveitis, and bilateral ankle arthralgias. Chest radiography shows marked symmetrical bilateral hilar lymphadenopathy and right paratracheal lymph node enlargement (Garland triad / 1-2-3 sign) without parenchymal pulmonary infiltrates. Under the Scadding classification system for thoracic sarcoidosis, what stage is this presentation?

  1. Stage 0
  2. Stage I Correct answer.
  3. Stage II
  4. Stage III

Explanation

According to the Scadding radiographic staging for sarcoidosis: Stage 0 is normal; Stage I is bilateral hilar lymphadenopathy (BHL) without parenchymal infiltration; Stage II is BHL with parenchymal infiltration; Stage III is parenchymal infiltration without BHL; and Stage IV is end-stage pulmonary fibrosis.

Question 25Thoracic and cardiovascular imaging patterns

A 56-year-old man with 25 years of occupational exposure in quarry excavation presents for evaluation. Chest radiography and unenhanced CT demonstrate multiple bilateral small centrilobular and subpleural nodules in the upper lobes, accompanied by prominent calcification along the periphery of enlarged hilar and mediastinal lymph nodes. Which characteristic radiological sign is described?

  1. Popcorn calcification
  2. Tram-track bronchial calcification
  3. Eggshell calcification of lymph nodes indicative of silicosis Correct answer.
  4. Curvilinear asbestos pleural plaque calcification

Explanation

'Eggshell' calcification refers to thin, peripheral rim-like calcification along the capsular margins of hilar and mediastinal lymph nodes. Although seen in sarcoidosis and treated lymphoma, it is classically associated with chronic occupational silicosis and coal workers' pneumoconiosis.

Question 26Thoracic and cardiovascular imaging patterns

A frontal chest radiograph of a 55-year-old male with an endobronchial mass reveals complete collapse of the left upper lobe. The collapsed lobe shifts anteriorly and superiorly, creating a crescent of aerated lung between the aortic arch and the medial aspect of the collapsed lobe. Which classic radiological sign is this?

  1. Golden S sign
  2. Flat waist sign
  3. Hampton hump sign
  4. Luftsichel sign Correct answer.

Explanation

The 'Luftsichel' sign (German for 'air crescent') is seen in left upper lobe collapse. Because the left lung lacks a minor fissure, the hyperextended superior segment of the left lower lobe herniates upward between the mediastinum (aortic knuckle) and the collapsed, anteriorly displaced left upper lobe.

Question 27Thoracic and cardiovascular imaging patterns

A 58-year-old male with treated cavitary tuberculosis from 10 years ago presents with intermittent episodes of mild hemoptysis. Chest CT reveals a mobile, round, heterogeneous soft-tissue mass resting inside a pre-existing thick-walled cavity in the right apex, separated from the superior wall by a crescent of gas (Monod sign). What is the definitive imaging diagnosis?

  1. Simple pulmonary aspergilloma (mycetoma) Correct answer.
  2. Acute necrotizing cavitary pneumonia
  3. Primary cavitating squamous cell carcinoma
  4. Ruptured hydatid cyst (Echinococcus granulosus)

Explanation

A simple aspergilloma (mycetoma or fungal ball) represents saprophytic colonization of a pre-existing tuberculous or bullous cavity. On CT, it manifests as a dependent, mobile mass of hyphae and debris that shifts when the patient changes position from supine to prone, surrounded by a gas crescent (Monod sign).

Question 28Thoracic and cardiovascular imaging patterns

A 36-year-old male presents with a severe odontogenic infection of the lower molars, high fever, neck swelling, and acute retrosternal chest pain with respiratory distress. Contrast-enhanced CT of the neck and chest demonstrates diffuse cervical fascial phlegmon extending directly downward through the 'danger space' into the posterior mediastinum, with fluid collections, extensive soft-tissue stranding, and pockets of gas. Which life-threatening surgical emergency is demonstrated?

  1. Acute mediastinal histoplasmosis
  2. Descending necrotizing mediastinitis (DNM) Correct answer.
  3. Esophageal duplication cyst rupture
  4. Acute fibrous mediastinitis from sarcoidosis

Explanation

Descending necrotizing mediastinitis (DNM) is a life-threatening complication of deep cervical or odontogenic infections spreading downward into the mediastinum through the retropharyngeal and 'danger spaces' (between the alar and prevertebral fascias). CT is the definitive diagnostic modality, demonstrating mediastinal fluid, fat stranding, gas, and abscess formation.

Question 29Abdominal and pelvic imaging: localization and pattern analysis

A 19-year-old male presents to the emergency surgical service with 24 hours of periumbilical pain radiating to the right iliac fossa, fever, and rebound tenderness. Graded-compression ultrasonography of the right lower quadrant is performed. Which combination of sonographic findings establishes the definitive diagnosis of acute appendicitis?

  1. Compressible tubular structure measuring 4 mm in outer diameter with peristalsis
  2. Collapsed blind-ending loop surrounded by clear ascites with normal wall thickness
  3. Non-compressible, blind-ending tubular structure with an outer diameter greater than 6 mm, target sign on cross-section, and hyperemic wall on color Doppler Correct answer.
  4. Echogenic mucosal focus with posterior acoustic shadowing inside the terminal ileum

Explanation

The established sonographic criteria for acute appendicitis on graded compression include an aperistaltic, non-compressible blind-ending tubular structure with an outer diameter exceeding 6 mm, mural thickening (> 2 mm), a 'target' or 'halo' pattern in transverse section, appendiceal wall hyperemia on color Doppler, and prominent echogenic periappendiceal fat stranding.

Question 30Abdominal and pelvic imaging: localization and pattern analysis

A 44-year-old multiparous woman presents with severe right upper quadrant pain, nausea, vomiting, and low-grade fever after consuming fatty foods. Transabdominal ultrasonography reveals impacted stones in the gallbladder neck, diffuse gallbladder wall thickening of 5 mm, pericholecystic fluid, and exquisite focal tenderness when the transducer directly compresses the visible gallbladder. What is this crucial clinical-ultrasound finding called?

  1. Courvoisier sign
  2. Rovsing sign
  3. Blumberg sign
  4. Sonographic Murphy sign Correct answer.

Explanation

The sonographic Murphy sign refers to maximal focal tenderness elicited by direct mechanical compression with the ultrasound probe over the visualized gallbladder. Combined with gallstones, wall thickening (> 3 mm), and pericholecystic fluid, its positive predictive value for acute calculous cholecystitis exceeds 92%.

Question 31Abdominal and pelvic imaging: localization and pattern analysis

A 68-year-old male with a history of peptic ulcer disease presents with sudden, catastrophic epigastric pain and board-like abdominal rigidity. On a supine abdominal radiograph, gas is seen outlining both the inner mucosal and outer serosal surfaces of the small bowel wall. What is this classic radiographic sign of massive pneumoperitoneum?

  1. Rigler sign (double wall sign) Correct answer.
  2. Football sign
  3. Inverted V sign
  4. Chilaiditi sign

Explanation

Rigler's sign (double wall sign) occurs when free intraperitoneal gas outlines the outer serosal surface of the bowel wall while normal intraluminal gas outlines its inner mucosal surface, making both sides of the bowel wall distinctly visible as a sharp linear stripe on supine radiographs.

Question 32Abdominal and pelvic imaging: localization and pattern analysis

A 60-year-old female with a prior history of open hysterectomy presents with cramping abdominal pain, obstipation, and bilious vomiting. Contrast-enhanced abdominal CT shows multiple small bowel loops dilated to 3.8 cm with intraluminal air-fluid levels, an abrupt transition point in the right lower quadrant, and collapsed distal ileal loops and colon. No intraluminal mass, mural hematoma, or inflammatory stranding is identified at the transition point. What is the most likely etiology?

  1. Adenocarcinoma of the small bowel
  2. Postoperative peritoneal adhesive band Correct answer.
  3. Gallstone ileus with Rigler triad
  4. Ileocolic intussusception

Explanation

Postoperative peritoneal adhesions account for 60-75% of mechanical small bowel obstructions. On CT, an adhesive band typically manifests as an abrupt discrete transition point from dilated to collapsed loops without intrinsic mural thickening, soft-tissue mass, or abnormal calcification.

Question 33Abdominal and pelvic imaging: localization and pattern analysis

A 38-year-old male with acute small bowel obstruction undergoes emergency abdominal CT. The scan demonstrates a C-shaped loop of distended fluid-filled small bowel with two transition points converging at a single anatomical site, severe mesenteric vessel twisting ('whirl sign'), engorged mesenteric veins, and diminished mural enhancement of the closed loop. What critical condition does this signify?

  1. Simple paralytic ileus secondary to hypokalemia
  2. Uncomplicated distal partial adhesive obstruction
  3. Closed-loop small bowel obstruction with impending strangulation and ischemia Correct answer.
  4. Acute pseudomembranous colitis with toxic megacolon

Explanation

A closed-loop obstruction occurs when a bowel segment is occluded at two points along its length (e.g., beneath an adhesive band or internal hernia), trapping secretions and gas. The mesenteric 'whirl sign', converging vascular pedicles, and poor mural enhancement indicate vascular compromise, representing a surgical emergency to prevent transmural necrosis and perforation.

Question 34Abdominal and pelvic imaging: localization and pattern analysis

An 82-year-old institutionalized male with chronic constipation presents with massive abdominal distension and obstipation. An abdominal radiograph reveals a huge, ahaustral, gas-distended loop of large bowel arising from the pelvis and projecting toward the right upper quadrant, with its medial walls converging toward the left lower quadrant, resembling a bent inner tube or coffee bean. Which diagnosis is confirmed?

  1. Sigmoid volvulus Correct answer.
  2. Cecal volvulus
  3. Acute appendiceal mucocele
  4. Intussusception of the transverse colon

Explanation

Sigmoid volvulus accounts for the vast majority of colonic volvulus cases in elderly patients. Torsion of the redundant sigmoid loop on its mesentery produces the classic 'coffee-bean' or bent inner-tube sign, with the apex pointing toward the right upper quadrant and the converging limbs arising from the left lower quadrant.

Question 35Abdominal and pelvic imaging: localization and pattern analysis

A 38-year-old asymptomatic woman undergoes an abdominal ultrasound, revealing a well-defined, homogeneous, hyperechoic mass measuring 3.5 cm in hepatic segment VII. A multiphase contrast-enhanced CT of the liver is performed. Which dynamic enhancement pattern is pathognomonic for a cavernous hepatic hemangioma?

  1. Intense, rapid homogeneous enhancement in the early arterial phase with immediate washout in the portal venous phase
  2. Early, peripheral, nodular, discontinuous enhancement during the arterial phase with progressive, centripetal 'puddle' fill-in on portal venous and delayed phases Correct answer.
  3. Homogeneous arterial enhancement with non-enhancing central stellate scar that enhances on delayed phases
  4. Continuous thick, irregular rim enhancement with central non-enhancing necrosis

Explanation

Cavernous hemangioma is the most common benign mesenchymal hepatic tumor. Its diagnostic hallmark on multiphase CT/MRI is peripheral, globular, nodular discontinuous enhancement on the arterial phase, followed by progressive centripetal fill-in that matches the attenuation of the blood pool (aorta and portal vein) on delayed scans.

Question 36Abdominal and pelvic imaging: localization and pattern analysis

A 54-year-old male with chronic hepatitis B and cirrhosis undergoes liver ultrasound surveillance, which identifies a new 2.4 cm nodule in segment VI. Multiphase dynamic contrast CT is performed. Which dynamic enhancement behavior confirms the non-invasive diagnosis of Hepatocellular Carcinoma (HCC) without requiring biopsy according to AASLD and Cuban oncology guidelines?

  1. Peripheral nodular discontinuous puddling with complete delayed centripetal fill-in
  2. Persistent hypovascularity on all phases with marked delayed capsular retraction
  3. Non-rim arterial phase hyperenhancement followed by delayed-phase or portal venous phase 'washout' with an enhancing pseudo-capsule Correct answer.
  4. Uniform target-like peripheral halo on portal venous phase with no arterial enhancement

Explanation

In cirrhotic livers, the non-invasive diagnostic criteria for HCC (LI-RADS LR-5 / AASLD / Cuban clinical consensus) are met when a nodule >= 10 mm exhibits non-rim arterial phase hyperenhancement (APHE) followed by 'washout' appearance in the portal venous or delayed phase, often accompanied by an enhancing fibrous pseudocapsule.

Question 37Abdominal and pelvic imaging: localization and pattern analysis

A 32-year-old female taking oral contraceptives undergoes an abdominal MRI for non-specific upper abdominal discomfort. A solitary, well-circumscribed 4.5 cm liver lesion is identified. It shows bright, homogeneous enhancement on the arterial phase with rapid return to isointensity relative to liver on the portal phase, and contains a central stellate scar that is hypointense on T1, hyperintense on T2, and shows delayed gadolinium enhancement. What is the diagnosis?

  1. Hepatic adenoma (inflammatory subtype)
  2. Fibrolamellar hepatocellular carcinoma
  3. Biliary cystadenoma
  4. Focal nodular hyperplasia (FNH) Correct answer.

Explanation

Focal nodular hyperplasia (FNH) is a benign, non-neoplastic liver lesion resulting from a hyperplastic response to a pre-existing congenital vascular malformation. On MRI, its classic feature is vivid, homogeneous arterial enhancement with isointensity on portal/delayed phases, and a pathognomonic central stellate scar that is T2 hyperintense and shows characteristic delayed contrast enhancement.

Question 38Abdominal and pelvic imaging: localization and pattern analysis

A 26-year-old female presents with recurrent crampy abdominal pain, non-bloody diarrhea, low-grade fever, and weight loss. CT enterography demonstrates discontinuous segments of transmural mural hyperenhancement, marked submucosal edema, mesenteric fibrofatty proliferation ('creeping fat'), and engorged vasa recta perpendicular to the bowel wall ('comb sign') in the terminal ileum. What is the diagnosis?

  1. Crohn's disease (enfermedad de Crohn) Correct answer.
  2. Ulcerative colitis (colitis ulcerosa)
  3. Ischemic colitis
  4. Infectious typhlitis (neutropenic enterocolitis)

Explanation

Transmural inflammation, skip lesions (discontinuous involvement), mesenteric fibrofatty proliferation ('creeping fat'), and the 'comb sign' (mesenteric vascular engorgement of the vasa recta) are hallmark CT enterography findings of active Crohn's disease, distinguishing it from mucosal-limited ulcerative colitis.

Question 39Abdominal and pelvic imaging: localization and pattern analysis

A 45-year-old male presents with progressive dysphagia to both liquids and solids, accompanied by regurgitation of undigested food. A dynamic fluoroscopic barium swallow reveals marked dilatation and tortuosity of the esophageal body, absent primary peristalsis, and smooth, symmetric, tapered narrowing of the distal gastroesophageal junction. What classic radiological sign is demonstrated?

  1. Corkscrew esophagus
  2. Feline esophagus
  3. Apple-core defect
  4. Bird-beak (pico de pájaro) sign Correct answer.

Explanation

The 'bird-beak' (pico de pájaro) sign is pathognomonic of achalasia on barium esophagography. It results from persistent, failure of relaxation of the lower esophageal sphincter (LES) producing smooth, symmetric tapering at the gastroesophageal junction beneath a dilated, aperistaltic esophagus.

Question 40Abdominal and pelvic imaging: localization and pattern analysis

A 66-year-old male presents with weight loss, progressive constipation, and microcytic hypochromic anemia. A double-contrast barium enema reveals a short-segment (3.5 cm), irregular circumferential narrowing in the descending colon, characterized by rigid walls, shelf-like overhanging margins ('shouldering'), and mucosal destruction. Which pathognomonic radiographic sign is demonstrated?

  1. Apple-core sign (signo de corazón de manzana) indicative of colonic adenocarcinoma Correct answer.
  2. Lead-pipe colon indicative of chronic ulcerative colitis
  3. Cobblestone appearance indicative of transmural Crohn's colitis
  4. Thumbprinting sign indicative of acute mucosal ischemia

Explanation

The 'apple-core' sign (also called the napkin-ring sign) on barium enema is the classic radiological appearance of an annular, infiltrating primary colonic adenocarcinoma. The short-segment concentric luminal stenosis with mucosal ulceration and sharp, overhanging shoulders resembles an apple core eaten down to its center.

Question 41Abdominal and pelvic imaging: localization and pattern analysis

A 58-year-old male with early satiety and profound cachexia undergoes a biphasic barium meal and contrast-enhanced CT. The imaging demonstrates diffuse, circumferential, rigid wall thickening of the gastric body and antrum with loss of normal rugal folds, fixed narrowing, and complete lack of gastric distensibility, resembling a rigid leather bottle. What is the diagnosis?

  1. Benign hypertrophic gastropathy (Menetrier disease)
  2. Diffuse infiltrative gastric adenocarcinoma (linitis plastica) Correct answer.
  3. Gastric gastrointestinal stromal tumor (GIST)
  4. Corrosive acid-induced antral stricture

Explanation

Linitis plastica represents the diffuse, scirrhous subtype of infiltrative gastric adenocarcinoma (Lauren diffuse type / Bormann Type 4). The desmoplastic tumor infiltrates the submucosa and muscularis propria diffusely, leading to rigid, non-distensible stomach wall thickening resembling a 'leather bottle'.

Question 42Abdominal and pelvic imaging: localization and pattern analysis

An 76-year-old male with a known 6.2 cm infrarenal abdominal aortic aneurysm (AAA) presents with acute, severe back pain and hypotension. An emergent non-contrast abdominal CT is performed. Which radiological sign indicates impending or contained rupture of the aneurysm?

  1. Complete circumferential thin calcification of the aortic wall
  2. Diffuse uniform low attenuation of the intraluminal thrombus (< 20 HU)
  3. Displaced intimal calcification measuring 1 mm
  4. Hyperdense crescent sign (signo de la media luna hiperdensa) within the mural thrombus Correct answer.

Explanation

The 'hyperdense crescent sign' on unenhanced CT manifests as a curvilinear area of high attenuation (> 50-60 HU) within the mural thrombus or aortic wall. It represents acute, internal hemorrhage dissecting through the thrombus into the outer wall, signaling impending or acute contained aortic rupture.

Question 43Abdominal and pelvic imaging: localization and pattern analysis

A 61-year-old female presents with painless progressive obstructive jaundice, pruritus, and clay-colored stools. Ultrasound and MRCP show marked dilatation of the right and left intrahepatic bile ducts with complete non-union (interruption) at the hepatic confluence, while the gallbladder and common bile duct are completely collapsed. Which tumor of the biliary tract is this?

  1. Klatskin tumor (perihilar cholangiocarcinoma) Correct answer.
  2. Ampullary adenocarcinoma (ampuloma)
  3. Distal common bile duct cholangiocarcinoma
  4. Choledocholithiasis impacted in the sphincter of Oddi

Explanation

A Klatskin tumor is a perihilar cholangiocarcinoma arising at the bifurcation of the common hepatic duct. By obstructing the primary confluence, it causes marked intrahepatic biliary ductal dilatation with disconnection of right and left hepatic ducts, while the distal common bile duct and gallbladder remain decompressed.

Question 44Abdominal and pelvic imaging: localization and pattern analysis

A 39-year-old male presents with high swinging fever, right upper quadrant pain, and leukocytosis. Abdominal contrast-enhanced CT demonstrates a 6 cm round, well-defined fluid-attenuation lesion in the right hepatic lobe. The wall shows an inner hyperenhancing mucosal rim surrounded by an outer zone of low-attenuation edema in the adjacent hepatic parenchyma. What is this sign called?

  1. Spoke-wheel sign
  2. Double target sign (signo del doble blanco) characteristic of a pyogenic liver abscess Correct answer.
  3. Cartwheel sign
  4. Puddle sign

Explanation

The 'double target sign' on contrast CT consists of a central fluid-density necrotic cavity, an inner hyperenhancing rim (granulation tissue and fibrous wall), and an outer hypodense halo of non-enhancing edematous hepatic parenchyma. It is highly characteristic of an acute pyogenic hepatic abscess.

Question 45Abdominal and pelvic imaging: localization and pattern analysis

A 52-year-old male undergoes contrast-enhanced abdominal CT for flank pain. A 3.2 cm cystic lesion is identified in the upper pole of the left kidney. It contains multiple thin internal septa (< 1 mm) with perceptible but non-measurable contrast enhancement, and fine hairline calcifications in the wall. There are no thick septa, no nodular components, and no solid enhancing soft-tissue elements. Under the Bosniak renal cyst classification, what category is this lesion?

  1. Bosniak Category I
  2. Bosniak Category II
  3. Bosniak Category IIF Correct answer.
  4. Bosniak Category IV

Explanation

Bosniak Category IIF ('F' for follow-up) includes minimally complex cystic lesions: multiple thin septa, minimal perceptible (non-measurable) enhancement of hair-like septa, fine calcifications, or hyperdense non-enhancing cysts > 3 cm. These have a low risk of malignancy (< 5-10%) and require imaging surveillance at 6 and 12 months.

Question 46Abdominal and pelvic imaging: localization and pattern analysis

A 61-year-old male with microscopic hematuria undergoes multiphase renal CT (unenhanced, corticomedullary, nephrographic, and excretory phases). A 4.5 cm solid, exophytic cortical mass in the right kidney demonstrates intense, heterogeneous enhancement on the corticomedullary phase (> 120 HU) with rapid washout in the nephrographic phase, accompanied by internal areas of cystic necrosis. Which histological subtype of Renal Cell Carcinoma (RCC) is most strongly suggested?

  1. Chromophobe renal cell carcinoma
  2. Papillary renal cell carcinoma (Type 1)
  3. Papillary renal cell carcinoma (Type 2)
  4. Clear cell renal cell carcinoma (ccRCC) Correct answer.

Explanation

Clear cell RCC (ccRCC) accounts for 70-80% of all renal carcinomas. It is characteristically hypervascular on multiphase CT, exhibiting avid, heterogeneous enhancement in the early corticomedullary phase (often > 100-140 HU) followed by rapid de-enhancement (washout) on subsequent nephrographic and excretory phases, often with necrosis or hemorrhage.

Question 47Abdominal and pelvic imaging: localization and pattern analysis

A 54-year-old female with recurrent Proteus mirabilis urinary tract infections presents with chronic left flank pain, weight loss, and anemia. An abdominal CT demonstrates a non-functioning, globally enlarged left kidney with a large central staghorn calculus in the renal pelvis. Multiple rounded, low-attenuation fluid-filled calyces radiate outward from the pelvis, replacing the normal renal parenchyma and mimicking paw prints ('bear paw sign'). What is the diagnosis?

  1. Acute focal bacterial nephritis (lobar nephronia)
  2. Xanthogranulomatous pyelonephritis (XPN) Correct answer.
  3. Renal tuberculosis with autonephrectomy (putty kidney)
  4. Autosomal dominant polycystic kidney disease

Explanation

Xanthogranulomatous pyelonephritis (XPN) is a chronic granulomatous destructive inflammatory process usually caused by chronic staghorn calculus obstruction and recurrent Proteus or E. coli infections. The classic 'bear paw sign' on CT is caused by dilated calyces filled with pus and lipid-laden foamy macrophages radiating from the contracted pelvis.

Question 48Abdominal and pelvic imaging: localization and pattern analysis

A 68-year-old male undergoes multiparametric MRI of the urinary bladder for local staging of a newly diagnosed high-grade urothelial carcinoma. On high-resolution T2-weighted and diffusion-weighted imaging (DWI), a continuous, low-signal-intensity muscularis propria line is clearly preserved beneath the high-signal tumor base, without extravesical fat stranding. According to the Vesical Imaging-Reporting and Data System (VI-RADS), which assessment category does this represent?

  1. VI-RADS 1: Muscular invasion is extremely likely
  2. VI-RADS 2: Muscular invasion is equivocal
  3. VI-RADS 4: Muscular invasion is probable
  4. VI-RADS 2: Muscular invasion is unlikely (confined to mucosa/submucosa) Correct answer.

Explanation

In the VI-RADS classification: VI-RADS 1 and 2 indicate that muscularis propria invasion is unlikely (non-muscle-invasive bladder cancer, NMIBC: Ta, T1). The clear, uninterrupted hypointense muscularis propria band on T2 and DWI under a pedunculated or sessile lesion characterizes VI-RADS 2.

Question 49Abdominal and pelvic imaging: localization and pattern analysis

A 16-year-old adolescent presents to the emergency radiology service with 3 hours of sudden, severe left testicular pain, nausea, and an elevated transverse left hemiscrotum. Emergency high-resolution scrotal color and spectral Doppler sonography is performed. Which sonographic finding is diagnostic of acute complete testicular torsion?

  1. Hypervascularity of the testis and epididymal head with low-resistance arterial flow
  2. Complete absence of intratesticular parenchymal arterial and venous color and spectral Doppler flow Correct answer.
  3. Isolated hydrocele with normal testicular resistive indices between 0.6 and 0.7
  4. Intense peripheral flow surrounding a well-marginated non-vascularized epidermoid cyst

Explanation

Acute complete testicular torsion is a surgical emergency. The definitive diagnostic sonographic criterion is the complete absence of intratesticular arterial and venous blood flow on both color and spectral Doppler, compared to the normal contralateral testis. Identification of the 'whirlpool sign' in the spermatic cord is also highly specific.

Question 50Abdominal and pelvic imaging: localization and pattern analysis

A 31-year-old male presents with a painless, hard testicular mass. Scrotal ultrasonography demonstrates a solid, homogeneous, well-circumscribed, hypoechoic intratesticular mass without calcification or cystic degeneration, showing mild internal vascularity on color Doppler. What is the most common malignant testicular neoplasm matching this sonographic appearance?

  1. Mature teratoma of the testis
  2. Choriocarcinoma with extensive hemorrhage
  3. Testicular seminoma Correct answer.
  4. Embryonal cell carcinoma

Explanation

Seminoma accounts for approximately 40-50% of primary testicular germ cell tumors. Its classic sonographic appearance is a well-circumscribed, lobulated, uniformly hypoechoic solid intratesticular mass. Unlike non-seminomatous germ cell tumors, pure seminomas rarely display cystic necrosis, calcifications, or marked heterogeneity.