Identification of ureteral stones at reduced radiation exposure: a pilot study comparing conventional versus digital low-dosage linear slot scanning (Lodox®) radiography.

PURPOSE: Digital low-dosage, linear slot scanning radiography (Lodox®) is an imaging modality that can emit down to one-tenth the radiation of conventional X-ray systems. We prospectively evaluated Lodox® as a diagnostic imaging modality in patients with ureterolithiasis. METHODS: Conventional kidney-ureter-bladder (KUB) X-ray and Lodox® were performed in 41 patients presenting with acute flank pain due to unilateral ureteral stone confirmed by computed tomography. KUB X-ray and Lodox® images were then reviewed by four blinded readers (urology expert/resident, radiology expert/resident). Identification rates were compared using Pearson's Chi square test. The impact of different parameters on stone identification by Lodox® was evaluated using logistic regression and generalized linear mixed models. Inter-reader agreement was tested using Cohen's kappa coefficient. RESULTS: Median stone size was 5 mm (range 2-12), median stone density was 800 HU (range 200-1500). The identification rates of the urology expert were 68% for KUB X-ray and 90% for Lodox® (p = 0.014), and for all four readers 61% for KUB X-ray and 62% for Lodox® (p = 0.8). Radiation exposure for KUB X-ray and Lodox® was 0.45 mSv (SD ± 0.64) and 0.027 mSv (SD ± 0.038), respectively. Multivariable analyses showed an association between stone identification by Lodox® and stone size (p < 0.001), stone density (p = 0.005), lower body mass index (p = 0.005), and reader (p < 0.001). CONCLUSIONS: The high identification rates and low radiation doses of Lodox® make it a promising imaging modality for the diagnosis of ureteral stones. Further validation in larger cohorts, including performance evaluation for renal stones, is warranted. TRIAL REGISTRATION: http://www.controlled-trails.com/ISRCTN12915426.

Comparison of PSMA-ligand PET/CT and multiparametric MRI for the detection of recurrent prostate cancer in the pelvis.

PURPOSE: So far, there have been very few studies which provide a direct comparison between MRI and PSMA-ligand PET/CT for the detection of recurrent prostate cancer (rPC). This present study therefore aims to provide further clinical data in order to resolve this urgent clinical question, and thereby strengthen clinical recommendations. METHODS: A retrospective analysis was performed for patients who were scanned at our institution with whole-body PSMA-PET/CT (tracer: 68Ga-PSMA-11) between January 2017 and September 2018 in order to detect rPC. Amongst them, 43 underwent an additional pelvic MRI within 2 months. Both modalities were compared as follows: a consensus read of the PET data was performed by two nuclear physicians. All lesions were recorded with respect to their type and localization. The same process was conducted by two radiologists for pelvic MRI. Thereafter, both modalities were directly compared for every patient and lesion. RESULTS: Overall, 30/43 patients (69.8%) presented with a pathologic MRI and 38/43 (88.4%) with a pathologic PSMA-PET/CT of the pelvis. MRI detected 53 pelvic rPC lesions (13 of them classified as "uncertain") and PSMA-PET/CT detected 75 pelvic lesions (three classified as "uncertain"). The superiority of PSMA-PET/CT was statistically significant only if uncertain lesions were classified as false-positive. CONCLUSIONS: PSMA-PET/CT detected more pelvic lesions characteristic for rPC when compared to MRI. In order to detect rPC, a potential future scenario could be conducting first a PSMA-PET/CT. Combining the advantages of both modalities in hybrid PET/MRI scanners would be an ideal future scenario.

Can 3D ultrasound identify trochlea dysplasia in newborns? Evaluation and applicability of a technique.

Femoro-patellar dysplasia is considered as a significant risk factor of patellar instability. Different studies suggest that the shape of the trochlea is already developed in early childhood. Therefore early identification of a dysplastic configuration might be relevant information for the treating physician. An easy applicable routine screening of the trochlea is yet not available. The purpose of this study was to establish and evaluate a screening method for femoro-patellar dysplasia using 3D ultrasound. From 2012 to 2013 we prospectively imaged 160 consecutive femoro-patellar joints in 80 newborns from the 36th to 61st gestational week that underwent a routine hip sonography (Graf). All ultrasounds were performed by a pediatric radiologist with only minimal additional time to the routine hip ultrasound. In 30° flexion of the knee, axial, coronal, and sagittal reformats were used to standardize a reconstructed axial plane through the femoral condyle and the mid-patella. The sulcus angle, the lateral-to-medial facet ratio of the trochlea and the shape of the patella (Wiberg Classification) were evaluated. In all examinations reconstruction of the standardized axial plane was achieved, the mean trochlea angle was 149.1° (SD 4.9°), the lateral-to-medial facet ratio of the trochlea ratio was 1.3 (SD 0.22), and a Wiberg type I patella was found in 95% of the newborn. No statistical difference was detected between boys and girls. Using standardized reconstructions of the axial plane allows measurements to be made with lower operator dependency and higher accuracy in a short time. Therefore 3D ultrasound is an easy applicable and powerful tool to identify trochlea dysplasia in newborns and might be used for screening for trochlea dysplasia.