Parvinian, Ahmad

Objective: The purpose of this study was to evaluate the potential clinical value of spectral CT for image guidance during percutaneous thermal ablation, particularly investigating high monoenergetic (MonoE) for metal artifact reduction. Materials and Methods: A phantom experiment was performed in which an ablation probe was scanned in “continuous CT” (CCT) mode on a spectral CT scanner. ROI measurements quantified metal artifacts for conventional and MonoE CCT images. Subsequently, a retrospective reader study was conducted with 10 patient cases. Three radiologists reviewed cases to select the optimal MonoE setting and perform a Likert score rating (+2: MonoE preferred, −2: conventional preferred). Results: Phantom measurements indicated a reduction in metal artifact for high MonoE (150 keV: −46 HU) relative to conventional CCT (−122 HU). The MonoE setting preference was 151±21 keV. The mean Likert score was 1.2±0.7. Radiologists indicated a perceived benefit of high MonoE CCT when probe placement was near a critical structure. Conclusions: This study indicates a clinical preference for high MonoE CCT compared with conventional CCT. Insofar as spectral CCT can be offered at a clinically feasible time frame, our results support the assessment of 150 keV image to reduce metal artifact while maintaining satisfactory soft tissue contrast.

Abstract Background Percutaneous ablation of parathyroid adenomas provides a minimally invasive treatment option for primary hyperparathyroidism. However, the overall performance of this technique remains underexplored. This meta-analysis evaluates the effectiveness and safety of various ablation techniques for parathyroid adenomas. Methods Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, multiple databases, including Ovid MEDLINE and Cochrane, were systematically searched. Studies that provided separate data for radiofrequency (RF), microwave ablation (MWA), and ethanol ablation technique were included. Outcomes of interest were changes in serum calcium, PTH, and phosphorus levels, along with normocalcemia rates at 6 to 12 months after ablation. Safety outcomes included transient hoarseness, permanent hoarseness, severe hemorrhage, major complications, and severe hypocalcemia. Data were pooled using a random-effects model, with pooled prevalence and 95% CIs calculated. Also, the publication bias was assessed with Egger's test for each outcome measure. Results Twenty studies (815 patients) were included. The posttreatment normocalcemia rate at 6 to 12 months was 85.6% (95% CI, 80.48-90.72). Serum PTH and calcium levels significantly decreased, with mean differences of 101.49 pg/mL (95% CI, 73.50-129.48) and 0.39 mmol/L (95% CI, 0.34-.45), respectively. Permanent hoarseness and major complications were rare, with incidences of 0.28% (95% CI, 0.00-1.05) and 0.31% (95% CI, 0.00-1.09). The safety and efficacy outcomes of RF, MWA, and ethanol ablation were comparable. Conclusion Our findings indicate that percutaneous ablation of parathyroid adenomas is safe and effective within the first year of the treatment. Additionally, they suggest that RF, MWA, and ethanol ablation techniques can each be employed depending on patients' needs without particular limitations.

Abstract Appendiceal intussusception is a rare condition characterized by the telescoping or invagination of a portion or the entire appendix into the caecum or within the appendix itself. Diagnosing appendiceal intussusception can be challenging due to its rarity, non-specific symptoms, and lack of awareness among physicians. We present a case report of appendiceal intussusception caused by endometriosis presenting with recurrent abdominal pain in a young female that was initially missed on CT scan and laparoscopy and eventually diagnosed on CT enterography.

AbstractBackgroundComputed tomography (CT) is routinely used to guide cryoablation procedures. Notably, CT‐guidance provides 3D localization of cryoprobes and can be used to delineate frozen tissue during ablation. However, metal‐induced artifacts from ablation probes can make accurate probe placement challenging and degrade the ice ball conspicuity, which in combination could lead to undertreatment of potentially curable lesions.PurposeIn this work, we propose an image‐based neural network (CNN) model for metal artifact reduction for CT‐guided interventional procedures.MethodsAn image domain metal artifact simulation framework was developed and validated for deep‐learning‐based metal artifact reduction for interventional oncology (MARIO). CT scans were acquired for 19 different cryoablation probe configurations. The probe configurations varied in the number of probes and the relative orientations. A combination of intensity thresholding and masking based on maximum intensity projections (MIPs) was used to segment both the probes only and probes + artifact in each phantom image. Each of the probe and probe + artifact images were then inserted into 19 unique patient exams, in the image domain, to simulate metal artifact appearance for CT‐guided interventional oncology procedures. The resulting 361 pairs of simulated image volumes were partitioned into disjoint training and test datasets of 304 and 57 volumes, respectively. From the training partition, 116 600 image patches with a shape of 128 × 128 × 5 pixels were randomly extracted to be used for training data. The input images consisted of a superposition of the patient and probe + artifact images. The target images consisted of a superposition of the patient and probe only images. This dataset was used to optimize a U‐Net type model. The trained model was then applied to 50 independent, previously unseen CT images obtained during renal cryoablations. Three board‐certified radiologists with experience in CT‐guided ablations performed a blinded review of the MARIO images. A total of 100 images (50 original, 50 MARIO processed) were assessed across different aspects of image quality on a 4‐point likert‐type item. Statistical analyses were performed using Wilcoxon signed‐rank test for paired samples.ResultsReader scores were significantly higher for MARIO processed images compared to the original images across all metrics (all p < 0.001). The average scores of the overall image quality, iceball conspicuity, overall metal artifact, needle tip visualization, target region confidence, and worst metal artifact, needle tip visualization, iceball conspicuity, and target region confidence improved by 34.91%, 36.29%, 39.94%, 34.17%, 35.13%, and 45.70%, respectively.ConclusionsThe proposed method of image‐based metal artifact simulation can be used to train a MARIO algorithm to effectively reduce probe‐related metal artifacts in CT‐guided cryoablation procedures.