Effect of a dedicated PI-QUAL curriculum on the assessment of prostate MRI quality.

PURPOSE: The Prostate Imaging Quality (PI-QUAL) score is a metric to evaluate the diagnostic quality of multiparametric magnetic resonance imaging (MRI) of the prostate. This study evaluated the impact of a prostate MRI quality training lecture on the participant's ability to assess prostate MRI image quality. METHODS: Eighteen in-training-radiologists of varying experience in reviewing diagnostic prostate MRI assessed the image quality of ten examinations. Then, they attended a dedicated lecture on MRI quality assessment using the PI-QUAL score. After the lecture, the same participants evaluated the image quality of a new set of ten scans applying the PI-QUAL score. Results were assessed using receiver operating characteristic (ROC) analysis. The reference standard was the PI-QUAL score assessed by a fellowship trained abdominal radiologist with experience in reading prostate MRI. RESULTS: There was a significant improvement in the average area under the curve (AUC) for assessment of prostate MRI image quality from baseline (0.82; [0.576 - 0.888]) to post teaching (1.0; [0.954-1]), with an improvement of 0.18 (p < 0.03). When ROC curves were computed for different cohorts stratified based on year of training, difference ranged from 0.48 for second year residents to 0.32 for fourth year residents (p < 0.001-0.01). For abdominal imaging fellows, the pre-teaching AUC was 0.9 [0.557-1] and post teaching AUC was 1 [0.957-1], a difference of 0.1 (p = 0.20). CONCLUSIONS: A dedicated lecture on PI-QUAL improved the ability of radiologists-in-training to assess prostate MRI image quality, with variable impact depending on year of training.

Liquid Nitrogen-Based Cryoablation in In Vivo Porcine Tissue: A Pilot Study.

INTRODUCTION: Liquid nitrogen-based cryoablation induces freezing evenly throughout the probe tip surface, resulting in larger ablation volumes and faster treatment times. The purpose of this preliminary investigation is to determine the efficacy of the liquid nitrogen-based Visica2 Cryoablation System (Sanarus Technologies, Pleasanton, CA) in in vivo porcine kidney, liver, and fibro-fatty tissue. METHODS: Ablations were performed under ultrasound guidance in 4 Yorkshire pigs. The target lesion cross-section width (W) and depth (D) were 1 cm for liver (n=8), kidney (n=4), and head-neck (n=5) and 2 cm for kidney (n=4).  Expected axial length (L) of the resulting lesion is approximately 4 cm.  After three-day survival, the ablated tissue was harvested and histologically analysed. The mean width and depth were compared with the target diameter using a one-sample t-test. RESULTS: All animals survived the procedure. For the 1 cm target, mean dimensions (L x W x D) were 3.8±1.5 x 1.7±0.3 x 1.7±0.7 for liver, 3.0±0.5 x 2.0±0.4 x 1.7±0.6 for kidney, and 3.3±0.8 x 1.8±0.4 x 1.8±0.4 for head-neck.  Mean width and depth were significantly greater than desired dimension.  For the 2 cm target, mean dimensions were 3.2±0.5 x 3.1±0.8 x 1.9±0.7.  Mean width and depth were not significantly different to desired target. CONCLUSION: Our preliminary results show that the Visica2 liquid nitrogen-based cryoablation system can efficiently and reproducibly create ablation volumes in liver, kidney, and fibro-fatty tissue within 4 minutes and 12 minutes for 1cm and 2cm targeted diameters, respectively. Further investigation is necessary to determine the optimal freeze-thaw-freeze protocol for larger ablation volumes.
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A Venous Malformation in the Vastus Lateralis: Our Experience with Cryotherapy.

The present report describes a case of cryotherapy ablation in a 35-year-old woman with a 1.5 cm painful venous malformation (VM) in the right vastus lateralis muscle. After the patient had failed sclerotherapy, a single session of cryotherapy was performed that resulted in both technical and clinical success. At 8-month follow-up, there was no residual pain. The use of cryotherapy ablation for the treatment of an intramuscular VM has only been previously described on 1 occasion. Based on our results, cryotherapy is a promising therapy for fast and safe treatment for patients with venous vascular malformations.