Determining the Optimal Number of Core Needle Biopsy Passes for Molecular Diagnostics.

PURPOSE: The number of core biopsy passes required for adequate next-generation sequencing is impacted by needle cut, needle gauge, and the type of tissue involved. This study evaluates diagnostic adequacy of core needle lung biopsies based on number of passes and provides guidelines for other tissues based on simulated biopsies in ex vivo porcine organ tissues. METHODS: The rate of diagnostic adequacy for pathology and molecular testing from lung biopsy procedures was measured for eight operators pre-implementation (September 2012-October 2013) and post-implementation (December 2013-April 2014) of a standard protocol using 20-gauge side-cut needles for ten core biopsy passes at a single academic hospital. Biopsy pass volume was then estimated in ex vivo porcine muscle, liver, and kidney using side-cut devices at 16, 18, and 20 gauge and end-cut devices at 16 and 18 gauge to estimate minimum number of passes required for adequate molecular testing. RESULTS: Molecular diagnostic adequacy increased from 69% (pre-implementation period) to 92% (post-implementation period) (p < 0.001) for lung biopsies. In porcine models, both 16-gauge end-cut and side-cut devices require one pass to reach the validated volume threshold to ensure 99% adequacy for molecular characterization, while 18- and 20-gauge devices require 2-5 passes depending on needle cut and tissue type. CONCLUSION: Use of 20-gauge side-cut core biopsy needles requires a significant number of passes to ensure diagnostic adequacy for molecular testing across all tissue types. To ensure diagnostic adequacy for molecular testing, 16- and 18-gauge needles require markedly fewer passes.

Percutaneous Renal Cryoablation: Short-Axis Ice-Ball Margin as a Predictor of Outcome.

PURPOSE: To determine if CT characteristics of intraprocedural ice balls correlate with outcomes after cryoablation. MATERIALS AND METHODS: A retrospective review was performed on 63 consecutive patients treated with renal cryoablation. Preprocedural and intraprocedural images were used to identify the size and location of renal tumors and ice balls as well as the tumor coverage and ice-ball margins. Review of follow-up imaging (1 mo and then 3-6-mo intervals) distinguished successful ablations from cases of residual tumor. RESULTS: Patients who underwent successful ablation (n = 50; 79%) had a mean tumor diameter of 2.5 cm (range, 0.9-4.3 cm) and mean ice-ball margin of 0.4 cm (range, 0.2-1.2 cm). Patients with residual tumor (n = 13; 21%) had a mean tumor diameter of 3.8 cm (range, 1.8-4.5 cm) and mean ice-ball margin of -0.4 cm (range, -0.9 to 0.4 cm). Residual and undertreated tumors were larger and had smaller ice-ball margins than successfully treated tumors (P < .01). Ice-ball diameters were significantly smaller after image reformatting (P < .01). Ice-ball margins of 0.15 cm had 90% sensitivity, 92% specificity, and 98% positive predictive value for successful ablation. Success was independent of tumor location or number of cryoprobes. CONCLUSIONS: Ice-ball margin and real-time intraprocedural reformatting could be helpful in predicting renal cryoablation outcomes. Although a 0.5-cm margin is preferred, a well-centered ice ball with a short-axis margin greater than 0.15 cm strongly correlated with successful ablation.

Magnetic Resonance-Monitored Coaxial Electrochemical Ablation--Preliminary Evaluation of Technical Feasibility.

PURPOSE: To evaluate the technical feasibility of a coaxial electrode configuration to rapidly create a mechanically defined electrochemical ablation zone monitored by magnetic resonance (MR) imaging in real time. MATERIALS AND METHODS: A direct current generator supplied the nitinol cathode cage and central platinum anode for coaxial electrochemical ablation. Safety and efficacy were evaluated by measuring local pH, temperature, and current scatter in saline solutions. Ablation zone diameters of 3-6 cm (n = 72) were created on ex vivo bovine liver and verified by gross pathology. Feasibility of MR monitoring was evaluated using 8 swine livers to create ablations of 3 cm (n = 12), 4 cm (n = 4), and 5 cm (n = 4) verified by histology. RESULTS: Local pH was 3.2 at the anode and 13.8 at the cathode. Current scatter was negligible. Ablation progress increased relative to local ion concentration, and MR signal changes corresponded to histologic findings. In the ex vivo model, the times to achieve complete ablation were 15 minutes, 20 minutes, 35 minutes, and 40 minutes for diameters of 3 cm, 4 cm, 5 cm, and 6 cm, respectively. Ablation times for the in situ model were 15 minutes, 35 minutes, and 50 minutes for 3 cm, 4 cm, and 5 cm, respectively. CONCLUSIONS: The coaxial configuration mechanically defined the electrochemical ablation zone with times similar to comparably sized thermal ablations. MR compatibility allowed for real-time monitoring of ablation progress.

Diagnostic role of Gallium-68 DOTATOC and Gallium-68 DOTATATE PET in patients with neuroendocrine tumors: a meta-analysis.

BACKGROUND: Gallium-68 somatostatin receptor positron emission tomography (PET) has been used in the diagnosis of neuroendocrine tumors (NETs). The compounds often used in molecular imaging of NETs with PET are 68Ga-DOTATOC, 68Ga-DOTATATE, and 68Ga-DOTANOC. There is varying affinity to different somatostatin receptors. PURPOSE: To systematically review and perform a meta-analysis of published data regarding the diagnostic role of 68Ga-DOTATOC and 68Ga-DOTATATE PET in the diagnosis of NETs. MATERIAL AND METHODS: A comprehensive literature search of studies published through 30 April 2013 regarding 68Ga-DOTATOC and 68Ga-DOTATATE PET in the diagnosis of NETs was performed using the PubMed/MEDLINE, Embase, and Scopus databases. Pooled sensitivity and specificity of 68Ga-DOTATOC and 68Ga-DOTATATE PET in the diagnosis of NETs were calculated. The area under the receiver-operating characteristic (ROC) curve was calculated to measure the accuracy of 68Ga-DOTATOC and 68Ga-DOTATATE PET in the diagnosis of NETs. RESULTS: Ten studies comprising 416 patients with NETs were included in this meta-analysis. The pooled sensitivity of 68Ga-DOTATOC and 68Ga-DOTATATE PET in the diagnosis of NETs calculated on a per-patient-based analysis was 93% (95% confidence interval [CI] 89-96%) and 96% (95% CI 91-99%). The pooled specificity of 68Ga-DOTATOC and 68Ga-DOTATATE PET in diagnosing NETs was 85% (95% CI 74-93%) and 100% (95% CI 82-100%). The area under the ROC curve of 68Ga-DOTATOC and 68Ga-DOTATATE PET was 0.96 and 0.98, respectively, on a per-patient-based analysis. CONCLUSION: The molecular imaging agents 68Ga-DOTATOC and 68Ga-DOTATATE demonstrated high sensitivity and specificity in the diagnosis of NETs on PET scan. Although both are accurate tools in the diagnosis of NETs, 68Ga-DOTATATE PET may be more sensitive and specific than 68Ga-DOTATOC PET scan.