Ultrasound Practice Questions

Q: Based on the given ultrasound of the ovary, which radiological pattern is observed?

String of pearls sign. ***String of pearls sign*** - This is a classic ultrasound finding in **Polycystic Ovary Syndrome (PCOS)**, representing multiple small, peripheral **follicular cysts** arranged along the ovarian cortex. - These follicles typically measure **2-9 mm** in diameter and are characteristically distributed in a circular or 'string of beads' pattern. *Chocolate cyst* - Also known as an **endometrioma**, it typically appears as a cyst with **low-level internal echoes** ('ground-glass' echogenicity). - It is associated with **endometriosis** and does not present as a peripheral arrangement of multiple small follicular cysts. *Honeycomb appearance* - This term is often used to describe the ultrasound appearance of a **gestational trophoblastic disease** (specifically **molar pregnancy**) in the uterus, not the ovary. - It represents multiple cystic spaces within the placenta due to **hydropic villi**, distinct from the follicular arrangement seen in PCOS. *Ground -glass appearance* - This sonographic texture is characteristic of an **endometrioma** (chocolate cyst), reflecting the presence of **old blood products**. - It is not associated with the follicular collection pattern seen in polycystic ovaries.

Q: Why does the needle appear as a hyperechoic structure when inserted at approximately 60 degrees to the ultrasound beam?

Maximum reflection of ultrasound waves occurs at this angle. ***Maximum reflection of ultrasound waves occurs at this angle*** - When the needle is positioned near perpendicular (optimally 90 degrees, but significantly effective at 60 degrees), **specular reflection** ensures more waves return to the transducer. - This high-intensity return of signal makes the needle appear **hyperechoic** (bright white), facilitating better visualization during ultrasound-guided procedures. *The needle produces strong acoustic shadowing* - **Acoustic shadowing** occurs when sound waves are completely blocked or absorbed by a dense structure, creating a dark area deep to the object. - While needles can cause shadowing, this phenomenon explains the lack of signal behind the needle, not the **hyperechoic** appearance of the needle itself. *Anisotropy is minimized at this angle* - **Anisotropy** is a property most commonly seen in tendons and nerves where the structure's brightness changes based on the angle of the probe. - While related to the angle of incidence, this term specifically describes the **artifact** of structural darkening rather than the mechanism of needle visibility. *The ultrasound beam refracts through the needle* - **Refraction** is the bending of waves at an interface between two different media, which can cause image distortion or misplacement (ghosting). - Refraction does not contribute to a needle appearing **hyperechoic**; in fact, it can hinder accurate localization by shifting the apparent position of the needle.

Q: What is an absolute contraindication for transvaginal sonography?

Imperforate hymen. **Explanation:** **1. Why Imperforate Hymen is the Correct Answer:** Transvaginal Sonography (TVS) requires the insertion of a high-frequency probe into the vaginal canal. An **imperforate hymen** is a physical anatomical barrier where the hymen completely encloses the vaginal orifice. Attempting TVS in this condition is an **absolute contraindication** because the probe cannot be inserted without causing significant trauma, pain, and rupture of the hymenal membrane. In such cases, Transabdominal (TAS) or Transrectal (TRS) ultrasound are the preferred alternatives. **2. Analysis of Incorrect Options:** * **Placenta Previa (A):** Contrary to common misconceptions, TVS is considered the **gold standard** for diagnosing placenta previa. It is safer and more accurate than TAS because the probe is not inserted into the cervix; it remains in the vaginal fornix, allowing for precise measurement of the distance between the internal os and the placental edge without causing hemorrhage. * **Abruptio Placenta (C):** While ultrasound has low sensitivity for detecting abruption (it is primarily a clinical diagnosis), TVS is not contraindicated. It may be used to rule out previa or assess the cervix. * **Abnormal Uterine Bleeding (D):** TVS is the **first-line investigation** for AUB to evaluate endometrial thickness, polyps, or fibroids. **3. NEET-PG High-Yield Pearls:** * **TVS vs. TAS:** TVS uses higher frequency probes (5–7.5 MHz) providing better resolution but less depth compared to TAS (3.5–5 MHz). * **Early Pregnancy:** TVS can detect a gestational sac at **4.5–5 weeks**, whereas TAS requires **5.5–6 weeks**. * **Safety:** TVS is safe in pregnancy and does not increase the risk of miscarriage or bleeding in previa when performed correctly.

Q: What are the four standard probe placements for Focused Abdominal Sonogram for Trauma (FAST) in blunt thoraco-abdominal trauma?

Epigastrium, right and left lumbar regions, hypogastrium. **Explanation:** The **Focused Assessment with Sonography for Trauma (FAST)** is a rapid bedside screening test used to identify free intraperitoneal or pericardial fluid (hemorrhage) in patients with blunt thoraco-abdominal trauma. The goal is to visualize dependent areas where fluid is most likely to accumulate. **1. Why Option C is Correct:** The four standard probe placements correspond to specific anatomical "windows": * **Epigastrium (Subxiphoid):** To visualize the pericardial sac for hemopericardium or tamponade. * **Right Lumbar (Right Upper Quadrant):** To visualize **Morison’s Pouch** (hepatorenal recess), the most sensitive area for intraperitoneal fluid in a supine patient. * **Left Lumbar (Left Upper Quadrant):** To visualize the perisplenic space and the splenorenal recess. * **Hypogastrium (Suprapubic):** To visualize the Pouch of Douglas (rectovesical pouch in males or rectouterine pouch in females) behind the bladder. **2. Analysis of Incorrect Options:** * **Options A, B, and D:** These options include regions like the "iliac fossa" or "lower chest" (which are part of the *Extended* FAST or E-FAST for pneumothorax) or use "hypochondrium" which, while close, does not accurately describe the standard sonographic windows required to visualize the deep recesses of the lumbar/flank areas where fluid collects. **3. High-Yield NEET-PG Pearls:** * **E-FAST:** Adds two more views (bilateral anterior upper chest) to look for pneumothorax (absence of "lung sliding"). * **Sensitivity:** FAST is highly specific but has limited sensitivity for hollow viscus injury or retroperitoneal bleeds. * **The "Gold Standard" for Hemodynamically Stable Patients:** If FAST is negative but suspicion is high, a Contrast-Enhanced CT (CECT) is the investigation of choice. * **First sign of fluid:** Usually appears in Morison’s Pouch.

Q: Hydrops fetalis is defined sonographically by?

Two or more fetal effusions. **Explanation:** **Hydrops Fetalis** is a serious fetal condition characterized by an abnormal accumulation of fluid in fetal soft tissues and serous cavities. **1. Why Option B is correct:** Sonographically, the diagnosis of hydrops fetalis requires the presence of **two or more** abnormal fetal fluid collections. These include: * **Ascites** (fluid in the abdomen) * **Pleural effusion** (fluid around the lungs) * **Pericardial effusion** (fluid around the heart) * **Skin edema/Anasarca** (defined as skin thickness >5 mm) **2. Why the other options are incorrect:** * **Option A:** A single effusion (e.g., isolated ascites) is insufficient for a diagnosis of hydrops; it may be due to a localized cause like a bowel perforation. * **Option C:** Anasarca (generalized skin edema) is a common feature of hydrops, but it is not diagnostic on its own. It must be accompanied by at least one other effusion to meet the criteria. * **Option D:** While this description often fits a hydropic fetus, the formal diagnostic threshold is lower. You do not *need* anasarca if two other effusions (e.g., ascites and pleural effusion) are present. **Clinical Pearls for NEET-PG:** * **Classification:** Divided into **Immune** (Rh isoimmunization) and **Non-immune** (now more common, >90% of cases). * **Most common cause of Non-immune Hydrops:** Cardiovascular arrhythmias or structural defects. * **Mirror Syndrome:** A rare complication where the mother "mirrors" the fetal hydrops, developing edema and preeclampsia-like symptoms. * **First sign:** Fetal ascites is often the earliest sonographic sign of developing hydrops.

Question 1

Based on the given ultrasound of the ovary, which radiological pattern is observed?

Accepted Answer

String of pearls sign

Answer

Chocolate cyst

Answer

Honeycomb appearance

Answer

Ground -glass appearance

Question 2

Why does the needle appear as a hyperechoic structure when inserted at approximately 60 degrees to the ultrasound beam?

Accepted Answer

Maximum reflection of ultrasound waves occurs at this angle

Answer

The needle produces strong acoustic shadowing

Answer

Anisotropy is minimized at this angle

Answer

The ultrasound beam refracts through the needle

Question 3

What is an absolute contraindication for transvaginal sonography?

Accepted Answer

Imperforate hymen

Answer

Placenta previa

Answer

Abruptio placenta

Answer

Abnormal uterine bleeding

Question 4

What are the four standard probe placements for Focused Abdominal Sonogram for Trauma (FAST) in blunt thoraco-abdominal trauma?

Accepted Answer

Epigastrium, right and left lumbar regions, hypogastrium

Answer

Epigastrium, right hypochondrium, left lower chest, hypogastrium

Answer

Epigastrium, right and left hypochondria, right iliac fossa

Answer

Hypogastrium, right and left lumbar regions, right lower chest

Question 5

Hydrops fetalis is defined sonographically by?

Accepted Answer

Two or more fetal effusions

Answer

One fetal effusion

Answer

Anasarca

Answer

Two or more fetal effusions with anasarca

Ultrasound — MCQs

Ultrasound — MCQs

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