AHCP AB/SS Midterm Review

Torsion is the most common cause of acute scrotal pain among adolescents, with the peak incidence at age 14, and is the only scrotal pain as a primary cause.

Each testis has a fine echo texture, smooth and homogeneous, medium gray. The head of the epididymis is seen, along with the rete testis, mediastinum(most echogenic structure), transmediastinal(or transtesticular) artery(50% of the time), capsular artery, recurrent ramiand area of the spermatic cord.

Epididymis head, rete testis, mediastinum, transmediastinal artery, and area of the spermatic cord are usually seen with u/s. In addition, the testis is surrounded by the tunica albuginea, visceral and parietal tunica vaginalis, bare area on posterior wall and spermatic cord. The epididymis body and tail are present but not seen on u/s unless infection is present.

Occurs through the veins of the pampiniform plexus, which exits from the mediastinum testis and courses in the spermatic cord. Converges into 3 anastomotic veins: the testicular, deferential and cremasteric. The right testicular vein drains into the inferior vena cava and the left testicular vein drains into the left renal vein. The deferential vein drains into the pelvis veins and the cremasteric vein drains into tributaries of the epigastric and deep pudenal veins.

• Symmetric, oval-shaped glands residing in the scrotum. Adult size:
• 3-5 cm Length
• 2-4 cm Width
• 3 cm Height
• Epididymis is 6-7 cm tubular structure beginning superiorly and coursing posterolateral to the testis. Divided into head, body and tail.
• Head: 6-15 mm Width

• Adult thyroid:
• 40-60 mm Length (4-6 cm)
• 20-30 mm AP (2-3 cm)
• 15-20 mm Width (1.5-2 cm)
• 2-6 mm Isthmus AP

Mediastinum

Begins superiorly of the testis and courses posterolateral. The body follows the posterolateral aspect of the testis from the upper to lower pole. The tail is positioned posterior to the lower pole. At the upper pole of the testis, the appendix testis is attached. It is located between the testis and epididymis.

Four

Adenoma

High-resolution, 7.5-15 MHz linear transducers, commonly in adjunct with 3-D and harmonics. Color Doppler may show a hypervascular pattern or a peripheral vascular arc that may aid in the differentiation from hyperplastic regional lymph nodes, which have hilar flow.

Fine, homogeneous echotexture that is more echogenic than the surrounding muscle structures, with echogenicity similar to that of the liver and testis. The vascular structures may be seen as tubular anechoic structures within the gland. Color Doppler with a low PRF will distinguish these structures as blood-filled. The muscles surrounding the gland (infrahyoid, sternocleidomastoid, and longus colli) are hypoechoic compared with the thyroid tissue. The esophagus may be seen to the left of the midline, next to the trachea, with a hypoechoic rim surrounding an echogenic center.

Thyroglossal duct cyst, anterior to the trachea.

• Anterior structures:
• Strap muscles-thin, hypoechoic bands anterior of the gland
• 1. sternohyoid
• 2. omohyoid
• 3. sternothyroid
• Sternocleidomastoid-large, oval band anterior and lateral to the gland. Palpable along the side of the neck.

• Posterior structures:
• Longus colli-posterior and lateral to each thyroid lobe, appears as a hypoechoic triangular structure adjacent to the cervical vertebrae

• ***All secretions are regulated by the hypothalamus, located in the brain, and stored elsewhere.
• Hormones are released in a 2-pronged stimulation effect.
• 1. Iodine metabolism
• 2. (TSH) Thyroid-stimulating hormone, produced by the pituitary gland and regulated by the hypothalamus.
• The three hormones released by the thyroid are:
• 1. (T3) Triiodothyronine
• 2. (T4) Thyroxine
• 3. Calcitonin

Thyroid enlargement, often visible on the anterior neck.

A solitary nodule may be present, but the risk of malignancies decreases with the presence of multiple nodules. A solitary thyroid nodule in the presence of cervical adenopathy suggests malignancy. The neoplasm can be of any size, single or multiple, and can appear as a solid, partially cystic, or largely cystic mass, occasionally presenting as a small, solid nodule. Thyroid cancer is usually hypoechoic realtive to normal thyroid. Calcifications are present in 50%-80% of all types of thyroid carcinoma. Increased vascularity may be present.

Adenoma

Compression of adjacent tissue and fibrous encapsulation. They range from anechoic to completely hyperechoic and commonly have a periperal, sonolucent halo.

Bone, kidneys and intestines

• There are two types of thryoiditis:
• 1. Hashimoto's-most common form of thyroiditis. Caused by an autoimmune disorder
• 2. de Quervain's-caused by a viral infection
• ***Differential considerations for any type of thyroiditis is neoplasm.

Isthmus

Both testicular cancer and torsion are much more likely to occur with cryptorchidism(undescended testicle).

Fluid collection, made up by proteinaceous fluid and spermatazoa, located in the head of the epididymis. May contain internal echoes and/or septations. Usually has smooth walls with posterior acoustic enhancement.

germ-cell tumors, specifically seminomas

• Most tumors appear as focal, hypoechoic masses.
• Seminomas tend to be homogeneous with smooth borders that do not often contain calcifications or cystic components.
• Embryonal cell carcinomas are heterogeneous and less well circumscribed that may contain areas of increased echogenicity due to calcification, hemorrhage or fibrosis. They may also invade the tunica albuginea and distort the testicular contour.
• Teratomas may show dense foci that produce acoustic shadowing. They are normally heterogeneous but have well-defined borders. They are usually benign in children but malignant in adults.
• Choriocarcinoma has a varied sonographic appearance because of mixed cell types. Its appearance is determined by the dominant cell type, but it typically has irregular borders.
• ***U/S imaging cannot differentiate malignant from benign masses. Neither color Doppler nor Doppler waveforms can reliably distinguish between flow patterns of benign and malignant tumors.

• Gray scale findings depend on how much time has passed since the torsion occurred. In the early stages, the scrotal contents may have a normal sonographic appearance.
• After 4-6 hours, the testis becomes swollen and hypoechoic. The lobes within the testis are usually well identified during this time as a result of interstitial and septal edema.
• After 24 hours, the testis becomes heterogeneous as a result of hemorrhage, infarction, necrosis and vascular congestion. The epididymal head appears enlarged and may have decreased echogenicity or become heterogeneous.
• In some cases, the twisted spermatic cord knot may be seen as a round or oval extratesticular mass that can be traced back to normal spermatic cord.
• Other findings may include scrotal skin thickening and reactive hydrocele.
• Color Doppler imaging can be used to demonstrate an absence of flow within the testis.

Enlarged thyroid gland

• An abnormal dilation of the veins of the pampiniform plexus (located within the spermatic cord).
• Usually caused by incompetent venous valves within the spermatic vein (primary varicoceles.)
• More common on the left, due to the mechanics pertaining to the left spermatic vein and left renal vein.
• Secondary varicoceles are caused by increased pressure on the spermatic vein, usually due to renal hydronephrosis, abdominal mass or liver cirrhosis.
• Any noncompressible varicocele in a man over 40 should prompt a search for a retroperitoneal mass.

• The breast is a modified sweat gland located in the superficial fascia of the anterior chest wall.
• The major portion of the breast tissue is situated between the 2nd or 3rd rib superiorly, the 6th or 7th costal cartilage inferiorly, the anterior axillary line laterally, and the sternal border medially.
• In many women, the breast extends deep toward the lateral upper margin of the chest and into the axilla. This extension is referred to as the tail of spence.

• New or growing dominant, discrete breast lump with:
• hard, gritty, or irregular surface
• usually (not always) painless
• does not fluctuate with hormonal cycle
• distinguish from "lumpy" breast tissue
• up to 5% can occur outside the reach of mammography
• fixed or poorly movable mass
• Unilateral single duct nipple discharge
• spontaneous, persistent; serous or bloody
• Surface nipple lesions
• non-healing ulcer
• focal irritation
• New nipple retraction
• New focal skin dimpling or retraction
• Unilateral new or growing axillary lump
• Hot, red breast

• Breast malignancies usually have the following 3 characteristics:
• noncompressible
• hypervascular
• immobile and fixed to deeper structures
• They are also hyperemic with a resistive index <0.4.
• Sonographically, they usually are/have:
• heterogeneous
• ill-defined, irregular, spiculated margins with sharp, angular microlobulations
• calcifications
• taller than wide
• strong attenuators
• hypoechoic, weak internal echoes

• Lymphatic drainage form all parts of the breast generally flows to the axillary lymph nodes.
• The flow of lymph moves from the intramammary nodes and deep nodes centrifugally toward the axillary and internal lymph node chains.
• It is estimated that only 3% of lymph is eliminated by the internal chain, whereas 97% is removed by the axillary chain.

• Upper outer quadrant
• near the tail of spence
• contains the most lobes
• usually contains more pathology
• Upper inner quadrant
• Lower outer quadrant
• Lower inner quadrant

• The boundaries of the breast--the skin line, nipple, and retromammary layer--generally give strong, bright echo reflections
• The areolar area has a slightly lower echo reflection
• The internal nipple may show low to bright reflections with posterior shadowing, and it has a variable appearance
• Subcutaneous fat is hypoechoic, whereas Cooper's ligaments and other connective tissue appear echogenic and are dispersed in a linear pattern.
• The fatty tissue interspersed throughout the mammary/glandular layer dictates the amount of intensity reflected from the breast parynchema. If little fat is present, there is a uniform architecture with a strong echogenic pattern (because of collagen and fibrotic tissue).
• When fatty tissue is present, areas of low-level echoes become intertwined with areas of strong echoes from the active breast tissue.