Minho Park MD, Abstract Co-Author: Nothing to Disclose

Sung Kyoung Moon, Presenter: Nothing to Disclose

Seong Jin Park MD, PhD, Abstract Co-Author: Nothing to Disclose

Joo Won Lim, Abstract Co-Author: Nothing to Disclose

Dong Ho Lee MD, Abstract Co-Author: Nothing to Disclose

Young Tae Ko MD, PhD, Abstract Co-Author: Nothing to Disclose

To assess the diagnostic accuracy of US for the evaluation of pediatric NS patients with urinalysis abnormality (UA) compared with MDCT as a reference standard.

This study included 66 pediatric patients with UA who underwent MDCT and US for the past 7 years. Eighteen patients with other biopsy-proven or clinically diagnosed renal diseases were excluded. MDCT and US images of 48 patients were reviewed retrospectively. By CT, AP diameters of the left renal vein (LRV) at the hilum (CDh) and aortomesenteric space (AMS, CDa) and the diameter ratio (CDh/a) were assessed. The presence of a beak sign of LRV at AMS and corticomedullary enhancement difference between both kidneys (CMD) in the portal phase were assessed. Patients were grouped as Gr 1 (high NS probability) and Gr 2 (low NS probability) according to the following CT criteria: 1) CDh/a>4; 2) presence of beak sign; and 3) presence of CMD. Patients with two or more criteria were categorized as Gr 1. By US, the AP diameters of LRV at the hilum (UDh) and AMS (UDa), diameter ratio (UDh/a), flow velocity at the hilum (Vh) and AMS (Va), and flow velocity ratio (Vh/a) were assessed. Twenty-four-hour urine proteinuria tests and US parameters were compared using an independent t-test.

Gr 1 and 2 comprised 30 and 18 patients, respectively. The mean CDh, CDa, and CDh/a in Gr 1 were 9.9±1.2 mm, 1.9±0.5 mm, and 5.9±3.2 mm, respectively. The mean CDh, CDa, and CDh/a in Gr 2 were 9.0±1.5 mm, 2.9±0.8 mm, and 3.4±1.1 mm, respectively. A significant difference existed in the 24-h urine proteinuria level between the groups (216.3±49.0 mg/d in Gr 1 vs. 133.4±58.8 mg/d in Gr 2; P<0.001). UDh, UDa, and UDh/a showed no significant difference (Gr 1 vs. Gr 2: 8.0±1.5 mm vs. 7.5±1.4 mm, 1.3±0.4 mm vs. 1.4±0.4 mm, and 6.7±2.3 mm vs. 5.7±2.0 mm, respectively; P>0.05). Vh, Va, and Vh/a showed no significant difference (Gr 1 vs. Gr 2: 22.5±7.6 cm/s vs. 22.0±6.7 cm/s, 135.0±30.4 cm/s vs. 122.1±37.7 cm/s, and 7.8±9.0 cm/s vs. 5.9±2.3 cm/s, respectively; P>0.05).

Based on MDCT, precise diagnosis of NS by US is difficult. Thus, US should be performed with care in patients who may have NS.

When NS is doubtful in US, MDCT should be considered for a more accurate diagnosis, even in pediatric patients.

Park, M, Moon, S, Park, S, Lim, J, Lee, D, Ko, Y, Diagnostic Accuracy of Ultrasonography (US) Examination for the Evaluation of Nutcracker Syndrome (NS): Comparison with Multidetector-row Computed Tomography (MDCT) as a Reference Standard.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13044351.html