AB-Abdomen Abdomen Sonography Examination Questions and Answers

Histoplasmosis is a fungal infection that can lead to granulomatous disease. Chronic granulomatous infections may result in multiple splenic calcifications that appear as small echogenic foci with shadowing on ultrasound. Other infectious granulomas (e.g., tuberculosis) may present similarly.

According to Rumack's Diagnostic Ultrasound:

“Granulomatous infections such as histoplasmosis and tuberculosis may produce multiple splenic calcifications, often with shadowing.”

The image shows a small hepatic lesion located very close to the anterior liver capsule, as indicated by the arrow. When imaging very superficial or near-field structures like subcapsular hepatic lesions, using a standoff pad is the most effective technique for optimizing visualization.

A standoff pad (also known as an acoustic stand-off or gel pad) helps increase the distance between the transducer and the superficial target. This improves the focus and beam shape for near-field imaging and minimizes reverberation and ring-down artifacts. It allows better evaluation of superficial lesions by positioning them within the focal zone of the transducer, which is usually set a few millimeters below the probe surface.

Differentiation from other options:

A. Decrease depth: While reducing depth can help center deeper lesions in the field of view, it does not address issues with near-field resolution.

B. Scan in upright position: This may help in gallbladder or fluid positioning but is not optimal for improving visualization of superficial liver lesions.

C. Move the transducer focus: Adjusting focus deeper into the image won't enhance resolution of very superficial structures unless a standoff is used to bring the lesion into the focal zone.

Acute pyelonephritis is a bacterial infection of the renal parenchyma and collecting system. Classic clinical findings include fever, flank pain, leukocytosis (elevated white blood cells), and pyuria (white blood cells in urine). Ultrasound may demonstrate renal enlargement, decreased echogenicity, and loss of corticomedullary differentiation.

Nephrocalcinosis (A) involves calcium deposition without infection.

Staghorn calculus (B) may lead to infection but is primarily characterized by obstructive uropathy.

Renal cell carcinoma (C) presents with hematuria and mass formation rather than infection symptoms.

Reference Extracts:

Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th ed. Elsevier, 2017. Chapter: Kidneys.

Middleton WD, Kurtz AB, Hertzberg BS.Ultrasound: The Requisites. 3rd ed. Elsevier, 2015.

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The normal hepatic vein Doppler waveform is triphasic, reflecting cardiac cycle variations in central venous pressure transmitted from the right atrium through the IVC. Loss of triphasicity may suggest elevated right atrial pressures or hepatic venous obstruction.

According to Rumack’s Diagnostic Ultrasound:

“The normal hepatic vein waveform is triphasic due to transmitted right atrial pressure variations.”

The image shows a transverse view of the left lobe of the liver with the portal triads clearly visible. The "parallel channel" or "double barrel" sign is observed—where dilated intrahepatic bile ducts run alongside the portal veins, creating a characteristic sonographic pattern of paired anechoic (black) tubular structures.

This sonographic feature is diagnostic for dilated intrahepatic bile ducts and is typically seen in obstructive jaundice or biliary obstruction from conditions such as:

Choledocholithiasis (stone in the common bile duct)

Stricture or mass compressing the bile ducts

Cholangiocarcinoma

The intrahepatic bile ducts normally are too small to visualize clearly unless dilated. Their dilation gives the liver a "too many tubes" appearance, where bile ducts become as prominent as the portal veins.

Comparison of answer choices:

A. Normal intrahepatic ducts are not usually seen this clearly or prominently on ultrasound.

B. Dilated intrahepatic — Correct. The parallel channel sign supports this diagnosis.

C. Dilated common bile duct would be visualized extrahepatically, typically anterior to the portal vein near the head of the pancreas.

D. Dilated common hepatic duct is also extrahepatic and seen in the porta hepatis, not within the liver parenchyma.

An intimal flap in the aorta is a hallmark ultrasound finding of aortic dissection, which can present with tearing chest/abdominal pain and differential blood pressures between arms. The flap represents separation of the intimal and medial layers of the aortic wall.

According to Rumack’s Diagnostic Ultrasound:

“An intimal flap visualized within the aorta is diagnostic of an aortic dissection.”

The correct sequence of renal arterial branching is: renal artery → segmental arteries → interlobar arteries → arcuate arteries → interlobular arteries. This branching pattern is important for understanding renal perfusion and evaluating vascular disorders.

According to Moore’s Clinically Oriented Anatomy:

“Renal arteries divide into segmental branches, which give rise to interlobar arteries, then arcuate arteries, and finally interlobular arteries.”

Wooden foreign bodies are often difficult to detect on CT because of their low radiodensity, but they are highly echogenic with posterior shadowing or reverberation on ultrasound, making ultrasound superior for detecting retained wooden objects. Glass, metal, and stones are better visualized with CT due to their high radiodensity.

According to AIUM and musculoskeletal ultrasound literature:

“Wood is poorly visualized on CT but demonstrates high reflectivity and acoustic shadowing on ultrasound.”

Salivary glands are superficial structures, and high-frequency transducers (10–15 MHz) are optimal to obtain high spatial resolution. Lower frequencies are inappropriate as they lack sufficient resolution for superficial structures. A 12 MHz transducer provides excellent detail necessary for detecting small lesions, duct abnormalities, and vascular structures.

According to Rumack et al., Diagnostic Ultrasound:

"High-frequency linear transducers (10–15 MHz) are recommended for evaluating superficial structures such as salivary glands." (Rumack CM et al., Diagnostic Ultrasound, 5th ed.).

The ultrasound image reveals a well-defined, anechoic (black), thin-walled fluid collection located in the subcutaneous or parenchymal plane of the breast. This is most consistent with a seroma, particularly in the context of recent breast surgery.

A seroma is a common postsurgical finding, representing a sterile collection of serous fluid that accumulates in the surgical bed. It typically appears:

Anechoic (or hypoechoic if older)

Well circumscribed

Without internal septations or debris

Lacking hyperemia or surrounding inflammatory changes

This contrasts with:

A. Carcinoma — typically presents as an irregular, hypoechoic mass with angular margins, internal vascularity, and shadowing.

B. Blood clot (hematoma) — often appears heterogeneous, with internal echoes and variable echotexture depending on the age of the clot.

C. Abscess — appears as a complex fluid collection with thick walls, internal debris, septations, and surrounding hyperemia (often with clinical signs of infection).

D. Seroma — Correct. The described anechoic, clean-walled fluid collection is classic for a postoperative seroma.

On ultrasound, tendons appear as cord-like hyperechoic structures with linear fibrillar echotexture when imaged in long axis. The fibrils are highly reflective, creating the typical hyperechoic appearance. Posterior shadowing is not typical unless there is calcification.

According to Rumack’s Diagnostic Ultrasound:

“Tendons have a highly organized hyperechoic linear fibrillar pattern when examined along their long axis.”

The ultrasound images show a heterogeneous, solid-appearing mass within the right kidney. The patient has a history of hypertension and hematuria—classic clinical features that raise suspicion for renal cell carcinoma (RCC), especially in an adult.

Renal cell carcinoma is the most common primary malignant tumor of the kidney in adults. Common presenting symptoms include:

Hematuria (most frequent symptom)

Flank pain

Palpable abdominal mass

Hypertension (due to increased renin secretion)

Sometimes paraneoplastic syndromes (e.g., polycythemia due to erythropoietin production)

Ultrasound Features of RCC:

Solid renal mass, often with heterogeneous echotexture

May contain cystic components, calcifications, or necrotic areas

May distort the renal contour

Doppler may show internal vascularity

Differentiation from other options:

B. Adenoma: Rare and typically small, benign cortical lesions. They do not typically present with hematuria or hypertension and cannot be reliably distinguished from RCC on ultrasound.

C. Nephroblastoma (Wilms tumor): Pediatric renal tumor seen almost exclusively in children under age 5.

D. Pheochromocytoma: Arises from the adrenal gland (not the kidney); associated with hypertension but not hematuria.

The ultrasound image labeled “SAG LT KIDNEY MID” demonstrates a left kidney with two separate, centrally located echogenic renal sinuses separated by intervening renal parenchyma. This appearance is classic for a duplicated collecting system.

A duplicated collecting system (also known as duplex kidney) is a congenital anomaly in which a single kidney contains two separate pelvicalyceal systems. It may be complete (with two ureters) or incomplete (partial duplication of ureters). This condition is one of the most common congenital anomalies of the urinary tract.

Sonographic Features of a Duplicated Collecting System:

Two separate central echogenic renal sinus regions seen within one kidney

Intervening parenchyma between the two sinuses

May show associated findings: hydroureteronephrosis (especially of upper pole moiety), ureterocele

Best visualized in sagittal plane

Differentiation from other options:

A. Horseshoe kidney: Shows fusion of the lower poles of the kidneys, typically located anterior to the aorta in the midline—not demonstrated here.

B. Crossed renal ectopia: One kidney is located on the opposite side of the body; this image shows a normally positioned kidney.

C. Prominent renal column (column of Bertin): May mimic a mass, but does not produce two separate sinuses as shown here.

The tunica albuginea is a dense fibrous capsule surrounding the testis. Discontinuity of the tunica albuginea on ultrasound is diagnostic of testicular rupture — a urologic emergency that requires immediate surgical repair to preserve testicular function and viability. Early surgical intervention within 72 hours has a high success rate for testicular salvage (up to 90%).

Intratesticular hematoma (A) may be managed conservatively if the tunica albuginea is intact.

Heterogeneity of the parenchyma (C) indicates injury but not necessarily rupture.

Increased vascularity (D) may be seen with inflammation or reperfusion but does not mandate surgery unless rupture is present.

Reference Extracts:

Dogra VS, Bhatt S. "Acute painful scrotum: ultrasound evaluation." Radiologic Clinics of North America. 2004; 42(2):349-363.

Middleton WD, Kurtz AB, Hertzberg BS.Ultrasound: The Requisites. 3rd ed. Elsevier, 2015.

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Direct inguinal hernias protrude through Hesselbach's triangle, which lies medial to the inferior epigastric artery. In contrast, indirect inguinal hernias pass lateral to the inferior epigastric artery via the deep inguinal ring.

According to Moore’s Clinically Oriented Anatomy:

“Direct inguinal hernias occur medial to the inferior epigastric vessels, within Hesselbach's triangle.”

A ultrasound image of a person's body AI-generated content may be incorrect.

The origin of the superior mesenteric artery (SMA)

The image provided is a color Doppler ultrasound scan of the abdominal aorta and its major branches. In the center of the image, just anterior to the aorta, we see the superior mesenteric artery (SMA) arising in the sagittal plane. This is the critical area for Doppler sampling in a patient with symptoms suggestive of mesenteric ischemia.

Severe postprandial pain in a young woman may be a manifestation of median arcuate ligament syndrome (MALS) or chronic mesenteric ischemia. Both of these conditions are assessed via Doppler sampling of mesenteric vessels, specifically:

The origin and proximal segment of the SMA

The celiac artery (especially for MALS)

Doppler waveform analysis should assess:

Peak systolic velocity (PSV): >275 cm/s suggests ≥70% SMA stenosis

Angle correction should be aligned properly

Sampling must be performed at the narrowest origin point (as shown in the image)

This type of Doppler interrogation is typically done in both fasting and postprandial states to evaluate changes in flow and symptom correlation.

Why this area?

The SMA is anterior to the aorta and travels inferiorly into the mesentery.

The site shown in the image is ideal for measuring PSV and evaluating for stenosis or extrinsic compression.

The ultrasound images (sagittal and transverse views of the left kidney) demonstrate a large, well-defined, heterogeneous mass within the renal parenchyma. This is highly characteristic of renal cell carcinoma (RCC), the most common primary renal malignancy in adults.

Renal cell carcinoma accounts for approximately 85% of all malignant renal tumors in adults. RCC often appears as:

A solid, heterogeneous, hypoechoic to isoechoic mass within the kidney

May contain areas of necrosis or hemorrhage (seen as mixed echogenicity)

Distortion of the normal renal contour

May have internal vascularity on Doppler imaging

Clear cell carcinoma (choice B) is the most common histological subtype of RCC but is not a separate diagnosis from RCC in imaging terms. Therefore, the most accurate answer is choice C: Renal cell carcinoma.

Differentiation from other options:

A. Nephroblastoma (Wilms tumor): A pediatric renal tumor, typically seen in children under 5 years of age—not applicable in adults.

B. Clear cell carcinoma: Histological subtype of RCC, not a distinct radiologic diagnosis.

D. Transitional cell carcinoma: Arises from the renal pelvis or ureter, typically appears as a central or collecting system mass rather than a cortical/parenchymal one.

The celiac trunk arises from the abdominal aorta and immediately divides into three primary branches:

Left gastric artery

Common hepatic artery

Splenic artery

The proper hepatic and gastroduodenal arteries are secondary branches of the common hepatic artery.

According to Moore’s Clinically Oriented Anatomy:

“The celiac trunk trifurcates into the left gastric, common hepatic, and splenic arteries.”

Chronic rejection presents sonographically as cortical thinning, decreased renal size, and increased echogenicity of the renal sinus fat. Acute rejection typically causes an enlarged, edematous kidney with increased parenchymal echogenicity but preserved size early on.

According to Zwiebel’s Introduction to Vascular Ultrasound:

“In chronic rejection, the allograft becomes smaller with cortical thinning, increased echogenicity, and prominence of the central sinus fat.”

The ultrasound images show two views of the same groin region — one without compression (left image labeled “W/O COMPRESSION”) and one with graded probe compression (right image labeled “W/ COMPRESSION”).

In the non-compression image, a hypoechoic mass-like structure is visible protruding through the abdominal wall, consistent with a hernia sac. On the compression image, the herniated content is no longer visible, indicating that the contents have been pushed back into the abdominal cavity. This is the hallmark feature of a reducible hernia.

Key characteristics of a reducible hernia on ultrasound:

Herniated contents are visible without pressure.

Contents disappear or reduce back into the abdomen with graded probe compression or Valsalva release.

Typically includes omental fat or bowel, but reduction confirms lack of incarceration or strangulation.

Comparison of answer choices:

A. Fat only refers to the hernia content type, not the behavior or reducibility shown here.

B. Reducible — Correct. The change in hernia appearance between images demonstrates successful reduction with compression.

C. Incarcerated hernia would remain visible and not compressible or reducible.

D. Strangulated hernia would show signs of ischemia (bowel wall thickening, absent perfusion, hyperechoic mesentery), and would also not reduce with compression.

The ultrasound image demonstrates a dilated common bile duct (CBD), measuring approximately 7.7 mm in diameter. A normal CBD should generally measure less than 6 mm in a patient under 60 years old and may increase approximately 1 mm per decade thereafter or after cholecystectomy.

In the absence of gallstones within the CBD, one of the most concerning causes of CBD dilation is distal obstruction due to an extrinsic compressive lesion. The most common and clinically significant cause of distal CBD obstruction is a mass at the head of the pancreas.

A pancreatic head mass (e.g., adenocarcinoma) may compress the distal CBD and pancreatic duct simultaneously, resulting in the “double duct sign” — dilation of both the CBD and pancreatic duct. This is a classic finding in pancreatic cancer.

Comparison of answer choices:

A. Liver mass — unlikely to cause isolated CBD dilation unless invading the porta hepatis.

B. Cystic duct stone — may cause gallbladder hydrops but typically not CBD dilation unless Mirizzi syndrome is present.

C. Pancreatic head mass — Correct. This is the most likely cause of painless progressive CBD dilation without visible intraductal stones.

D. Gallbladder stones — These may be associated with biliary colic or cholecystitis but typically do not cause CBD dilation unless the stone has migrated and obstructed the distal duct.

Annular pancreas is a congenital anomaly in which pancreatic tissue encircles the second part of the duodenum, potentially causing partial or complete duodenal obstruction (atresia). It is due to abnormal migration of the ventral pancreatic bud.

According to Rumack’s Diagnostic Ultrasound:

“Annular pancreas results from failure of the ventral pancreatic bud to rotate properly, leading to encirclement of the duodenum.”

Lateral decubitus positioning allows shifting of internal echoes within the bladder, helping differentiate mobile debris (such as blood clots or sediment) from adherent masses like tumors. This technique is helpful in evaluating questionable bladder filling defects.

According to Rumack’s Diagnostic Ultrasound:

“Changing the patient’s position, such as turning to the lateral decubitus, can help distinguish mobile debris from attached bladder wall lesions.”

The ultrasound image demonstrates a longitudinal view of the right kidney. Within the renal pyramids, there are multiple echogenic foci, some showing posterior acoustic shadowing—findings characteristic of medullary nephrocalcinosis. This sonographic appearance is strongly associated with medullary sponge kidney (MSK).

Medullary sponge kidney is a congenital disorder of the renal tubules that results in ectatic (dilated) collecting ducts in the renal medulla. The dilated ducts frequently become calcified, leading to the "paintbrush" or "bouquet of flowers" appearance seen in the renal pyramids on ultrasound. These calcifications are most often bilateral and symmetrical, further aiding the diagnosis.

Comparison of answer choices:

A. Fungal balls (mycetomas) typically appear as mobile, non-shadowing echogenic masses within the collecting system, often in immunocompromised patients.

B. Renal cell carcinoma usually presents as a solid mass with irregular borders and variable echogenicity—this image does not show a mass.

C. Acute pyelonephritis may show renal enlargement, decreased echogenicity, or loss of corticomedullary differentiation—but not calcification of the pyramids.

D. Medullary sponge kidney is correct due to the punctate echogenic foci within the medullary pyramids, consistent with nephrocalcinosis.

The ultrasound image demonstrates a well-defined, ovoid, hypoechoic to isoechoic mass within the subcutaneous tissue of the abdominal wall. The lesion appears compressible and shows linear striations parallel to the skin surface — a classic appearance of a lipoma.

Lipomas are the most common benign soft tissue tumors and frequently arise in the subcutaneous tissue. They are composed of mature adipose tissue and are typically asymptomatic unless large or compressing adjacent structures.

Sonographic features of a lipoma:

Isoechoic to mildly hyperechoic or hypoechoic relative to subcutaneous fat

Oval or elliptical in shape with well-defined margins

Internal linear striations or “feathered” echotexture

Compressible and non-vascular on Doppler imaging

Located in subcutaneous fat plane parallel to the skin surface

Differentiation from other options:

B. Fibroma: Typically appears as a homogeneous, hypoechoic mass but is far less common in the abdominal wall.

C. Desmoid: Appears as an ill-defined or infiltrative mass within deeper soft tissues; more heterogeneous and may distort surrounding tissue planes.

D. Metastasis: Often more irregular, heterogeneous, and may show increased vascularity or invasion into adjacent structures.

Reducing slice (section) width improves spatial resolution, particularly elevational resolution, which enhances visualization of small, superficial structures. Lower slice width reduces off-axis beam artifacts and blurring. Wavelength depends on transducer frequency, not adjustable directly during scanning.

According to Zwiebel’s Introduction to Vascular Ultrasound:

“Reduction in slice thickness improves imaging of small superficial structures by minimizing volume averaging and improving elevational resolution.”

In percutaneous procedures such as biopsies or drainages, maintaining a sterile field is critical to avoid introducing infection. While the transducer is covered by a sterile cover, the gel placed inside this cover (between the probe and the cover) must also be sterile, as it contacts the sterile field. The transducer itself and machine controls are not sterile but are handled appropriately to avoid field contamination.

According to the AIUM Guidelines:

"Sterile coupling gel must be used inside the sterile probe cover during all invasive or percutaneous procedures." (AIUM Guidelines for Cleaning and Preparing Ultrasound Transducers, 2021).

The ultrasound image provided shows the liver and diaphragm imaged in a coronal plane with characteristic rib shadows and costophrenic angles. The orientation of the image and the structures visualized suggest that the transducer is placed in the right mid-axillary line, with the sound beam directed coronally — this is a classic right coronal scanning approach.

Key features supporting this:

The liver appears superiorly in the image.

Multiple echogenic lines (representing the ribs) run obliquely, casting acoustic shadows.

The diaphragm and adjacent lung base are seen clearly, which is commonly imaged through the right intercostal spaces in a coronal plane.

Comparison of answer choices:

A. Anterior: Would show a more transverse view of the liver and not typically image the diaphragm and lung this way.

B. Posterior: Not used for upper abdominal scanning due to shadowing from the spine and posterior ribs.

C. Left coronal: Would show the spleen and left kidney — not the liver as seen here.

D. Right coronal — Correct. This image was obtained using the right coronal (intercostal) approach through the right flank.

Pancreas divisum occurs when the dorsal and ventral pancreatic ducts fail to fuse during embryologic development. This results in most pancreatic secretions draining through the minor papilla via the dorsal duct (duct of Santorini).

According to Rumack’s Diagnostic Ultrasound:

“In pancreas divisum, the dorsal and ventral pancreatic ducts fail to fuse, resulting in separate drainage systems.”

The ultrasound image shows echogenic foci with dirty shadowing and reverberation artifacts within the gallbladder wall and lumen. These features are characteristic of emphysematous cholecystitis, a severe, life-threatening variant of acute cholecystitis caused by gas-forming organisms (e.g., Clostridium or E. coli) infecting the gallbladder wall.

Sonographic features of emphysematous cholecystitis:

Echogenic gas within the gallbladder wall or lumen

Reverberation or "dirty" shadowing artifacts

May show intramural gas bubbles or "ring-down" artifact

Often seen in diabetic or immunocompromised patients

No gallstones may be present ("acalculous cholecystitis")

Clinical context:

More common in elderly men and diabetics

Presents with right upper quadrant pain, fever, and leukocytosis

Surgical emergency due to risk of perforation and sepsis

Differentiation from other options:

A. Adenomyomatosis: Involves gallbladder wall thickening with “comet tail” artifacts due to Rokitansky-Aschoff sinuses, not intramural gas.

B. Porcelain gallbladder: Shows curvilinear calcification of the gallbladder wall — dense echogenic rim with posterior shadowing.

C. Gangrenous cholecystitis: May show wall irregularity, intraluminal membranes, and absence of Doppler flow but lacks intramural gas.

The hallmark feature of focal nodular hyperplasia (FNH) is a central stellate scar seen on imaging. This fibrous scar may not always be seen on ultrasound but is a classic distinguishing feature from hepatic adenomas, which usually lack a central scar.

According to Rumack’s Diagnostic Ultrasound:

“Focal nodular hyperplasia often demonstrates a central stellate scar, which may be echogenic or isoechoic.”

The Duct of Santorini is the accessory pancreatic duct that drains the superior portion of the pancreatic head into the minor duodenal papilla. The main pancreatic duct (Duct of Wirsung) drains into the major papilla, often joining the common bile duct at the Ampulla of Vater.

According to Moore’s Clinically Oriented Anatomy:

“The accessory pancreatic duct (Duct of Santorini) may be present and drains into the minor duodenal papilla.”

The technique shown in the video is compression. In ultrasound imaging—especially of soft tissue masses, the bowel, or venous structures—compression is used to evaluate the compressibility of structures. The image demonstrates a classic grayscale ultrasound view of a lesion or structure being compressed with the probe.

Compression sonography is particularly important in:

Evaluating venous patency (e.g., for deep vein thrombosis)

Differentiating cystic from solid structures

Evaluating bowel wall abnormalities or intussusception

Assessing lymph nodes and soft tissue masses (as shown here)

When a structure compresses easily under probe pressure, it suggests that the lesion is fluid-filled or soft. In contrast, incompressibility may indicate a solid mass or thrombus.

Differentiation from other options:

B. Valsalva: Involves forced expiration against a closed airway, used primarily to assess venous reflux or inguinal hernias—not what is demonstrated here.

C. Exhalation: A respiratory maneuver that passively alters thoracoabdominal pressure, not actively performed by the operator or causing focal structural change.

D. Deep inspiration: Used to improve visualization of the liver, diaphragm, or gallbladder—not to evaluate the compressibility of soft tissue.

In biliary obstruction (such as at the ampulla of Vater), dilation begins proximally and progresses peripherally. The intrahepatic peripheral bile ducts are the last to dilate because backpressure takes time to propagate. Early dilation is typically seen in the common bile duct and common hepatic duct.

According to Rumack’s Diagnostic Ultrasound:

“The intrahepatic peripheral bile ducts dilate last in the setting of progressive biliary obstruction.”

Courvoisier sign describes the clinical finding of painless jaundice combined with a palpable, distended gallbladder. This typically results from obstruction at the distal common bile duct, often due to pancreatic head carcinoma or cholangiocarcinoma, leading to bile accumulation and gallbladder distention. In contrast, Mirizzi syndrome involves compression of the common hepatic duct by an impacted stone in the cystic duct.

According to Rumack's Diagnostic Ultrasound and standard clinical references:

“Courvoisier sign refers to a palpable, enlarged gallbladder due to obstruction of the distal bile duct, often from malignancy.”

De Quervain thyroiditis (subacute granulomatous thyroiditis) is often triggered by a viral infection. Patients may present with painful thyroid enlargement, elevated inflammatory markers, and transient hyperthyroidism. Hashimoto’s and Graves' diseases are autoimmune in nature.

According to Braverman’s The Thyroid:

“Subacute (De Quervain) thyroiditis typically follows a viral upper respiratory tract infection and is characterized by thyroid pain and transient thyrotoxicosis.”

The most serious long-term complication of undescended testis (cryptorchidism) is an increased risk of testicular malignancy, especially seminoma. Although torsion and hernia may also occur, seminoma is the most concerning complication due to its life-threatening potential.

According to Rumack’s Diagnostic Ultrasound:

“Cryptorchidism is associated with a significantly increased risk of seminoma, the most common malignancy in undescended testes.”

The clinical presentation—tender, swollen breast with erythema and fever—in a lactating female strongly suggests acute mastitis. The sonographic findings support this diagnosis. In the image, the breast parenchyma shows diffuse, hypoechoic, and heterogeneous echotexture with increased vascularity, which is consistent with inflammatory changes typical of mastitis.

Mastitis is a common complication during lactation, particularly in the first few weeks postpartum. It results from milk stasis and subsequent bacterial infection, commonly due to Staphylococcus aureus. Ultrasound features of mastitis include:

Ill-defined, hypoechoic, edematous areas in the breast parenchyma

Increased Doppler flow due to hyperemia

Skin thickening

Ductal dilatation may also be present

If left untreated, mastitis may progress to abscess formation, which would appear as a localized, complex fluid collection with peripheral hyperemia and internal debris. However, the image does not show a well-formed fluid collection consistent with abscess.

Option B (Ductal carcinoma): Inappropriate here due to the acute clinical scenario and patient age. Ductal carcinoma typically presents as a hypoechoic mass with irregular margins and posterior shadowing, not diffuse edema or inflammatory changes.

Option D (Galactocele): This benign milk-filled retention cyst typically appears anechoic or with fluid–fluid levels but lacks signs of inflammation and systemic symptoms such as fever.

Option A (Abscess): This could be a differential, but abscesses usually present with a well-defined anechoic or complex mass. The absence of a discrete collection and the diffuse appearance makes mastitis more likely.

The FAST exam is primarily used to detect free intraperitoneal or pericardial fluid in trauma patients, serving as a rapid, bedside assessment tool. While organ injuries may be suspected, the FAST exam is not primarily designed to assess for solid organ lacerations.

According to AIUM and ACEP guidelines:

“The primary goal of the FAST exam is to detect the presence of free fluid suggestive of hemorrhage in trauma patients.”

Retroperitoneal fibrosis can encase and compress the ureters, leading to obstructive uropathy and hydronephrosis. It may also involve other retroperitoneal structures but hydronephrosis is the most common significant complication.

According to Rumack’s Diagnostic Ultrasound:

“Retroperitoneal fibrosis frequently results in ureteral obstruction, leading to hydronephrosis.”

Changing the patient's position allows evaluation of lesion mobility. Blood clots and hematomas are often mobile, while true bladder wall masses remain fixed. This technique helps differentiate between solid masses and non-adherent debris.

According to Rumack’s Diagnostic Ultrasound:

“Changing patient position may distinguish between mobile blood clots and fixed bladder wall masses.”

Fine needle aspiration (FNA) uses a thin needle to aspirate cells, which are then packed into the lumen of the needle for cytological evaluation. It is distinct from core biopsy, which uses cutting needles to obtain tissue cores.

According to AIUM Practice Parameters:

“Fine needle aspiration involves insertion of a thin needle into a lesion to aspirate cells for cytologic analysis. The cells are collected inside the needle lumen.”

A thyroglossal duct cyst is the most common congenital cystic anomaly in the anterior midline neck. It arises from persistent remnants of the thyroglossal duct, typically located inferior to the hyoid bone.

According to Rumack’s Diagnostic Ultrasound:

“Thyroglossal duct cysts are located in the midline anterior neck and are the most common congenital cystic neck lesions.”

A complex pleural effusion often contains internal septations or fibrin strands, distinguishing it from simple anechoic effusion. These septations suggest exudative processes such as infection, malignancy, or hemothorax.

According to Rumack’s Diagnostic Ultrasound:

“Complex pleural effusions demonstrate internal septations or loculations, often related to infection or malignancy.”

The transverse ultrasound image of the liver shows a solid, hypoechoic mass located in the posterior aspect of the right lobe of the liver. In this view:

The anterior aspect of the liver is at the top of the image (near the transducer).

The posterior aspect is at the bottom (deeper).

The right lobe occupies the majority of the screen on transverse imaging when the probe is placed in the epigastrium or right upper quadrant.

Anatomically, the right lobe of the liver is divided into anterior and posterior segments by the right hepatic vein in the coronal plane. In transverse imaging:

The right anterior segment lies closer to the anterior abdominal wall.

The right posterior segment lies deeper (posteriorly).

Given that the mass is seen deep within the liver on the right side of the image, it is best localized to the right posterior segment (Segment VI or VII depending on the exact craniocaudal level).

Comparison of answer choices:

A. Left lateral is located far to the left of the image and typically appears higher and more anterior on transverse scans.

B. Left medial lies near the midline and would appear adjacent to the ligamentum teres or falciform ligament.

C. Right anterior lies closer to the transducer (top of the image), not posteriorly.

D. Right posterior — Correct. This is the segment shown deep in the right lobe of the liver.

The ultrasound image shows a classic longitudinal view of a markedly thickened pyloric muscle with an elongated pyloric channel. This finding is consistent with hypertrophic pyloric stenosis (HPS), a condition most commonly seen in male infants between 2 and 8 weeks of age.

The most characteristic clinical finding associated with HPS is an “olive-shaped” palpable mass in the right upper quadrant or epigastric region, which represents the hypertrophied pylorus.

Clinical presentation of HPS includes:

Non-bilious projectile vomiting (due to gastric outlet obstruction)

Dehydration and weight loss

A palpable “olive” mass on physical exam

Visible peristalsis may be noted on the abdominal wall

Sonographic diagnostic criteria for HPS:

Pyloric muscle thickness ≥ 3 mm

Pyloric channel length ≥ 15–17 mm

“Cervix sign” or “target sign” (transverse view)

Failure of gastric contents to pass through the pylorus on real-time imaging

Differentiation from other options:

B. Fever of unknown origin: Not characteristic of HPS.

C. Red currant jelly stools: Classic for intussusception.

D. Bilious vomiting: Seen in distal duodenal or jejunal obstruction, not in pyloric stenosis (vomiting is non-bilious in HPS).