AB-Abdomen ARDMS Exam Lab Questions

Patients with liver disease often have coagulopathy due to impaired synthesis of clotting factors. This places them at greater risk for bleeding or hematoma formation after biopsy. While hypertension may increase bleeding risk slightly, liver disease presents a significantly higher risk due to impaired coagulation.

According to the Society of Interventional Radiology (SIR) guidelines:

“Liver dysfunction is a significant risk factor for post-biopsy hemorrhage due to associated coagulopathy.”

The structure indicated by the arrow is the middle hepatic vein. This is confirmed by both its anatomical location within the liver and its Doppler waveform characteristics.

Key ultrasound and Doppler features:

The middle hepatic vein runs between the right and left hepatic lobes and drains into the inferior vena cava (IVC). On grayscale imaging, it appears as a tubular anechoic structure extending toward the IVC.

On spectral Doppler, hepatic veins (including the middle hepatic vein) demonstrate a characteristic triphasic waveform due to pressure changes in the right atrium. This triphasic pattern is clearly visible in the Doppler tracing below the image.

This differs significantly from the monophasic low-resistance flow of the hepatic artery or the continuous hepatopetal flow of the portal vein.

Differentiation from other options:

A. Left portal vein: Would show continuous, hepatopetal flow (toward the liver) and lies more anterior and medial within the liver.

C. Proper hepatic artery: Small-caliber vessel with low-resistance pulsatile waveform (not triphasic).

D. Inferior vena cava: Lies posterior to the liver and demonstrates phasic flow with respiration, but this vessel is more centrally located and not shown in this field of view.

The ultrasound image clearly demonstrates a thickened and elongated pyloric muscle with a visible channel, which is characteristic of hypertrophic pyloric stenosis (HPS). This condition is most commonly seen in male infants between 2 and 8 weeks of age who present with non-bilious projectile vomiting, dehydration, and a palpable “olive-like” mass in the right upper quadrant.

Ultrasound is the imaging modality of choice and is highly sensitive and specific for diagnosing pyloric stenosis.

Key sonographic criteria for HPS:

Muscle thickness >3 mm

Pyloric channel length >15–17 mm

“Target sign” or “doughnut sign” on transverse imaging (concentric rings)

“Cervix” or “railroad track sign” on longitudinal imaging (elongated canal with echogenic center)

Differentiation from other options:

A. Intussusception: Also shows a target sign, but it occurs in the right lower quadrant or periumbilical region, not in the gastric antrum.

C. Hydronephrosis: Refers to dilation of the renal pelvis and calyces — not gastrointestinal.

D. Gastritis: May show gastric wall thickening but lacks the distinct elongated, thickened pyloric muscle seen here.

Transudative pleural effusions result from imbalances in hydrostatic and oncotic pressures, most commonly caused by congestive heart failure (CHF). In CHF, elevated hydrostatic pressure in the pulmonary capillaries leads to fluid leakage into the pleural space without significant protein or cellular content (hence, transudate). Exudative effusions (associated with infections, malignancy, and inflammation) are more often seen with pulmonary emboli, lymphoma, or empyema.

According to Light’s criteria (which differentiates transudates from exudates):

"Congestive heart failure remains the leading cause of transudative pleural effusions." (Light RW. Pleural Diseases, 6th ed.).