PEDIATRIC RADIOLOGY: Genitourinary Radiology
Case Author: Krista L. Birkemeier, MD, Cincinnati Children’s Hospital Medical Center
History
15-year-old boy with hematuria, polyuria, and abdominal pain radiating to the right side of the scrotum.
Imaging Findings
Longitudinal gray-scale and color Doppler ultrasound images of the left (A and B) and right (C and D) kidneys show diffuse increased echogenicity of the medullary pyramids (arrows, A and C) and bilateral punctate focal areas of increased echogenicity with twinkle artifact (arrows, B and D).
The renal cortex is normal. Longitudinal gray-scale ultrasound image (E) inferior to the right kidney shows a large, round echogenic structure (arrow) in the proximal right ureter that exhibits posterior acoustic shadowing.
Diagnosis
Medullary nephrocalcinosis with urolithiasis
Teaching Points
The waveforms in the common femoral veins should be evaluated bilaterally to assess for indirect signs of more proximal obstruction, which can be intrinsic or extrinsic.
A monophasic waveform is abnormal and must be assessed further with imaging of the iliac veins up to and including the inferior vena cava if possible with ultrasound. If ultrasound is not adequate, CT or MRI should be performed. A monophasic waveform indicates more central disease at least 60% of the time.
Acute deep venous thrombosis typically enlarges the vein, though it can also cause a monophasic waveform if there is a long nonocclusive thrombus that severely narrows the lumen.
Causes of a monophasic waveform include intrinsic thrombosis, extrinsic compression from adenopathy or other pelvic mass (including pregnancy), or chronic obstruction, including a small scarred vessel.
Heart failure typically distends the vein and causes an abnormally pulsatile biphasic waveform with increased and reversed blood flow toward the feet during each heartbeat because of the increased right-sided pressure.
Suggested Readings
Hoppe B, Kemper MK. Diagnostic evaluation of the child with urolithiasis or nephrocalcinosis. Pediatr Nephrol 2010; 25:403–413
Slovis TL, Adler BH, Bloom DA, et al. Caffey’s pediatric diagnostic imaging, 11th ed. Philadelphia, PA: Mosby, 2008
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