Imaging in pediatric urolithiasis-what's the best choice?

Zero-echo time MRI: an alternative method for the diagnosis of urinary stones in children

OBJECTIVES

To evaluate the potential of zero-echo time-magnetic resonance imaging (ZTE-MRI) in the assessment of urolithiasis and compare ZTE-MRI with computed tomography (CT) in pediatric patients.

MATERIALS AND METHODS

This was a single-center, prospective cross-sectional study conducted between April 2023 and December 2023. 23 patients (12 girls, 11 boys; mean age: 12.3, range 1-18) with urinary tract stones detected on non-enhanced abdominal CT were enrolled. The images were evaluated independently by two radiologists for the presence, and number of stones in the kidneys, ureters, and bladder. In the second session, two radiologists evaluated whether urinary tract stones could be detected by MRI compared to CT, and the maximum diameter of the stones was measured. The CT and MRI results were compared with the Wilcoxon test. The agreement between the results of the observers was examined using Spearman's rho correlation coefficient and the intraclass correlation coefficient.

RESULTS

A total of 58 urinary tract stones were detected by CT and 39 of these were detected by MRI. Most of the stones that MRI could not detect were < 5 mm and the detection sensitivity of MRI increased in correlation with stone size (p < 0.001). There was poor intermodality agreement for stones < 5 mm, substantial agreement for stones 5-10 mm, and almost perfect agreement for stones > 10 mm. Interobserver agreement for stone detection on MRI was almost perfect for stones > 10 mm and 5-10 mm and was substantial for stones < 5 mm.

CONCLUSION

ZTE-MRI is a promising modality for detecting urinary stones without radiation exposure in children.

CLINICAL RELEVANCE STATEMENT

Zero-echo time-magnetic resonance imaging is a potential method for identifying urinary stones in children and other populations who are particularly sensitive to radiation.

KEY POINTS

Urinary system stone disease in children is increasing and imaging is needed for managing urolithiasis. Zero-echo time-magnetic resonance imaging (ZTE-MRI) had an accuracy of 81.8% and 93.7% for stones larger than 5 mm and 10 mm, respectively. ZTE-MRI is a potential non-irradiating method for the diagnosis and management of urolithiasis.

Clinical Features and Surgical Outcomes of the Children With Urolithiasis at a Tertiary Care Hospital: First Report From Somalia

INTRODUCTION

There are very few studies regarding pediatric urolithiasis (PU) reported from Africa, and to date, no data have been presented from Somalia. This study evaluated the sociodemographic and radiological characteristics, treatment, and outcome data of the PU patients treated at Somalia's only tertiary care center.

METHOD

The data of all patients diagnosed with urolithiasis during a 6-year period were reviewed. Only pediatric (age <18) urolithiasis patients were included. Demographic parameters, radiological features, stone characteristics, treatment, and outcome data were collected and analyzed.

RESULTS

Overall, 227 (127 male, 100 female) patients were included. The rate of PU was 8.1%. The mean patient age was 12.7 ± 3.2. More than two-thirds of the patients (n = 161, 70.9%) were adolescents. The stones were located in the kidney in 50.7%, the ureter in 33%, and the bladder in 14.5%. Distal ureteral stones (36%) accounted for the majority of ureteral stones, followed by the ureterovesical junction (26.7%) and proximal ureteral (24%) stones. The mean stone size was 16.2 mm. Most (42.3%) stones had a 10-20 mm diameter, while 23.3% were sized between 6 and 10 mm. Renal insufficiency was present in 5.3%. Among 227 patients, 101 (44.5%) underwent minimally invasive procedures including ureterorenoscopic lithotripsy (n = 40, 18%), retrograde intrarenal surgery (n = 30, 13.2%) and percutaneous nephrolithotomy (n = 31, 14%). Open pyelolithotomy was the most common surgery performed (n = 53, 22.3%). Surgical site infection developed following 3.5% of the open surgery cases. The stone-free rate was 91.3%. It was significantly higher in open cases (98%) compared to the cases performed via a minimally invasive approach (83%) (p = 0.02).

CONCLUSION

In Somalia, PU is more common than in many other countries. Open surgery continues to be the primary treatment modality for children with urolithiasis due to the restricted endourology resources. However, minimally invasive approaches have evolved over the last years.

Use of Ultrasound in Pediatric Renal Stone Diagnosis and Surgery

Pediatric urolithiasis is on the rise globally and incidence rates have risen by 6-10% annually over the past couple of decades. Given the increasing incidence, high likelihood of recurrence, and long life expectancy of children, the use of ionizing radiation in the diagnosis, management, and follow up of pediatric urolithiasis has been scrutinized recently and many institutions and organizations have emphasized the use of non-ionizing imaging modality such as ultrasound. This review examines the use of ultrasound in the diagnosis and treatment of pediatric urolithiasis. Specifically, the role of ultrasound in shockwave lithotripsy, percutaneous nephrolithotomy, and, more recently, ureteroscopy will be examined.