Detection of distal ureteral stones in pregnancy using transvaginal ultrasound

Michael S Bold,Douglas L Brown,Aaron M Potretzke,Erik B Sviggum,Carl H Rose,Thomas D Atwell,Brian C Goss,James H Boyum

doi:10.1007/s40477-020-00504-4

Michael S Bold, Douglas L Brown + Show 6 more

Open Access

https://doi.org/10.1007/s40477-020-00504-4

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Abstract

AimsTo determine the performance of transvaginal ultrasound for the visualization of distal ureteral stones in pregnant patients with renal colic and to evaluate the diagnostic value of secondary findings suggestive of obstructing ureteral stone disease.MethodsWe retrospectively identified 129 pregnant patients with a total of 142 encounters with both abdominal and transvaginal ultrasound. Ultrasound images for each patient were reviewed recording the presence of stone with location, hydronephrosis, resistive indices (RI), and status of the ureteral jets. Patients were subcategorized into two groups based on the visualization of distal ureteral stone.ResultsThe transvaginal technique identified 94% (N = 16/17) of sonographically detected stones in the distal ureter/urethra, while the transabdominal technique identified 29% (N = 5/17). The combined imaging for initial assessment of renal colic in pregnancy demonstrated a sensitivity of 89%, specificity 100%, and negative predictive value (NPV) of 98%. The frequency of hydronephrosis was statistically greater in the visualized stone group (94% vs 51%). Mean RI was identical in both groups however the delta RI was significantly elevated in those patients with distal ureteral stones with a mean delta RI value of 0.05. The rate of absence of ureteral jets was not statistically significant.ConclusionThe present data would suggest a utility of transvaginal ultrasound for the evaluation of the pregnant patient with 94% of distal stones being detected transvaginal versus 29% transabdominally. Additionally, there was significantly increased hydronephrosis and elevated RIs in patients with distal ureteral stones.

Highlights

Urolithiasis affects approximately 1 in 11 people in the United States and is diagnosed with high sensitivity and specificity using non-contrast computed tomography (NCCT) [1]
The first group included 115 patients with a total of 125 negative encounters which are defined as no identifiable distal ureteral stone but included stones in the kidney and ureteropelvic junction (UPJ) (110 patients with a single encounter, 3 patients with 2 encounters, 1 patient with 4 encounters and 1 patient with 5 encounters)
Two patients had UPJ stones missed by ultrasound, one confirmed by MRI and another by ureteroscopy

Summary

Introduction

Urolithiasis affects approximately 1 in 11 people in the United States and is diagnosed with high sensitivity and specificity using non-contrast computed tomography (NCCT) [1]. Rochester, MN, USA 4 Present Address: High Desert Radiology, Kingman, AZ, USA non-obstetric cause of hospital admission, but the definitive diagnosis of urolithiasis in pregnancy is more difficult, complicated by the desire to avoid exposing the fetus to radiation from computed tomography (CT) [2,3,4]. The performance of ultrasound in terms of sensitivity for ureteral stone detection has been suboptimal most previous studies were often performed exclusively with transabdominal techniques. Sensitivity is even lower for direct stone detection of ureteral calculi; reported rates are as low as 15% when compared to NCCT [6]

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