Diagnosis of the nutcracker phenomenon using two-dimensional ultrasonography

Area of Science:

• Pediatric Nephrology
• Diagnostic Imaging
• Vascular Ultrasound

Background:

• The nutcracker phenomenon (N phenomenon) is a condition affecting the left renal vein (LRV).
• Accurate diagnosis is crucial for managing pediatric hematuria.
• Current diagnostic criteria may lead to misdiagnosis.

Purpose of the Study:

• To establish novel ultrasonography (US) criteria for diagnosing the N phenomenon in children.
• To evaluate the utility of specific US-derived parameters in identifying the N phenomenon.
• To reduce misdiagnosis rates in children presenting with hematuria.

Main Methods:

• Ultrasonography (US) of the LRV was performed in 125 children (hematuria and control groups).
• Key parameters measured included D/N ratio, D/A ratio, and RVD difference.
• Diagnostic cutoff levels were established based on normal control group values (mean + 2 SD).

Main Results:

• The D/A ratio and RVD difference showed significant correlation with the D/N ratio.
• Proposed cutoff levels: D/N ratio 3.7, D/A ratio 0.75, RVD difference 1.7 mm.
• Using two or more parameters above cutoff diagnosed N phenomenon, identifying it in most macrohematuria and one-third of microhematuria cases.

Conclusions:

• The D/A ratio and RVD difference are valuable for diagnosing the N phenomenon.
• The newly established US criteria improve diagnostic accuracy for the N phenomenon.
• These criteria can effectively minimize misdiagnosis in pediatric patients.