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Testicular Torsion

KEY FACTS Terminology Spontaneous or traumatic twisting of testis & spermatic cord within scrotum → vascular occlusion/infarction Imaging ↓ or absent blood flow in testicle on Doppler US Transverse side-by-side comparison image of asymptomatic & symptomatic testicles very helpful Spiral twist of spermatic cord just above testis ± abnormal lie of testicle within scrotal sac Enlarged testis ± altered echotexture May see hyperemia after detorsion Top…

Epididymoorchitis

KEY FACTS Terminology Infectious inflammation of epididymis, testicle, or both Orchitis much less common than epididymoorchitis Imaging Enlargement of affected tissues (i.e., testicle, epididymis, or both) with accompanying ↑ blood flow ↑ blood flow best demonstrated on transverse side-by-side comparison view Arterial waveforms typically remain low resistance Echotexture may be ↑ or ↓, often heterogeneous Reactive hydrocele Scrotal wall also thickened Top Differential Diagnoses Torsion of…

Ovarian Torsion

KEY FACTS Terminology Definition: Twisting of vascular pedicle of ovary, fallopian tube, or both → venous obstruction → edema → arterial compromise → ischemia → hemorrhagic infarction Imaging Unilaterally enlarged ovary Ovarian volume > 100 mL highly suggestive of torsion Ovarian volume < 20 mL in postpubertal patient never torsed in 1 series Ratio of abnormal to normal ovarian volumes ≥ 5:1 strongly correlated with torsion…

Ovarian Cyst

KEY FACTS Terminology Follicle: Normal physiologic cyst < 1 cm in diameter Dominant follicle may measure up to 3 cm Functional cysts: Can measure up to 3-10 cm Corpus luteal cyst: Dominant follicle after ovulation Follicular cyst: Normal mature follicle fails to involute Hemorrhagic cyst: Hemorrhage into functional cyst Imaging US mainstay of ovarian imaging; MR in limited circumstances Well-marginated round or ovoid structure within borders…

Ovarian Teratoma

KEY FACTS Terminology Synonyms Dermoid tumor, dermoid cyst, mature cystic teratoma Definition Teratomas made up of variety of parenchymal cell types from > 1 germ cell layer, usually all 3 Imaging Best clue: Heterogeneous pelvic mass containing Ca²⁺, hair, fat, & cystic components Bilateral in up to 15% Typically well-defined margins without surrounding inflammatory changes US 1st-line modality for female pelvic pain &/or mass Multiple classic…

Neuroblastoma

KEY FACTS Terminology Malignant tumor of sympathetic chain primitive neural crest cells Increasing degrees of cellular differentiation/benignity along spectrum: Neuroblastoma (malignant) → ganglioneuroblastoma → ganglioneuroma (benign) Imaging Location Adrenal (35-48%) Extraadrenal retroperitoneum (25-35%) Posterior mediastinum (16-20%) Small round solitary mass vs. large multilobulated lesion Aggressive tumor with tendency to invade adjacent tissues Frequently engulfs & displaces adjacent vascular structures (rather than just displacing) Ca²⁺ in up…

Renal Stones

KEY FACTS Terminology Definition: Concretion in urinary system Imaging Most stones seen in kidneys & upper urinary tract Range in size from 1-2 mm to > 1 cm NECT most sensitive modality to detect stones Calcified density in urinary system Ultrasound shows hyperechoic urinary tract focus with posterior acoustic shadowing &/or twinkle artifact Signs of obstruction (US/CT/MR) Hydroureteronephrosis Nephromegaly Perinephric/periureteral edema Lack of ureteral jet in…

Pyelonephritis

KEY FACTS Terminology Acute infection of renal parenchyma; often difficult to clinically distinguish from lower UTI Imaging Imaging work-up of UTI controversial See professional society guidelines With pyelonephritis, marked inflammatory response to renal parenchymal infection causes swelling that alters normal tissue properties & effectively ↓ radiologic contrast agent delivery to site, which results in ↓ uptake on nuclear cortical scan ↓ perfusion on Doppler imaging with…

Wilms Tumor

KEY FACTS Imaging Ultrasound frequently 1st study performed; CECT & MR better characterize tumor & local extent Large, heterogeneous but predominantly solid hypoechoic (US)/hypoenhancing (CT/MR) renal mass Must carefully evaluate – Adjacent soft tissues for tumor rupture, adenopathy – Renal vein & inferior vena cava for tumor thrombus – Contralateral kidney for synchronous tumor or nephrogenic rests Chest radiograph or CT: Lung metastases in 10-20% Top…