MRI- Versus CT-Guided Renal Tumor Cryoablation: Is There a Difference?

PURPOSE: To compare procedure-related variables, safety, renal function, and oncologic outcomes in patients undergoing percutaneous cryoablation (CA) of renal tumors with MRI- or CT-guidance. MATERIALS AND METHODS: Patient, tumour, procedure, and follow-up data were collected and analysed. MRI and CT groups were matched using a coarsened exact approach according to patient's gender and age, tumour grade, size and location. P < 0.05 was considered statistically significant. RESULTS: Two-hundred fifty-three patients (266 tumors) were retrospectively selected. Following the coarsened exact matching 46 patients (46 tumors) in the MRI group and 42 patients (42 tumors) in the CT group were matched. There were no significant baseline differences between the two populations except for the duration of follow-up (P = 0.002) and renal function (P = 0.002). On average MRI-guided CA lasted 21 min longer than CT-guided ones (P = 0.005). Following CA, complication rates (6.5% for MRI vs 14.3% for CT; P = 0.30) and GFR decline (mean - 13.1 ± 15.8%; range - 64.5-15.0 for MRI; mean - 8.1 ± 14.8%; range - 52.5-20.4; for CT; P = 0.13) were similar in both groups. The 5-year local progression-free, cancer-specific and overall survivals in the MRI and CT groups were 94.0% (95% CI 86.3%-100.0%) and 90.8% (95% CI 81.3%-100.0%; P = 0.55), 100.0% (95% CI 100.0%-100.0%) and 100.0% (95% CI 100.0%-100.0%; P = 1), and 83.7% (95% CI 64.0%-100.0%) and 76.2% (95% CI 62.0%-93.6%; P = 0.41), respectively. CONCLUSIONS: Apart from increased procedural times associated with MRI-guided CA of renal tumors compared to CT-guidance, both modalities demonstrate similar safety, GFR decline and oncologic outcomes.

Safety and oncologic efficacy of percutaneous MRI-guided cryoablation of intraparenchymal renal cancers.

PURPOSE: The purpose of this study was to evaluate the safety and oncologic efficacy of percutaneous magnetic resonance imaging (MRI)-guided cryoablation of intraparenchymal renal cancer. MATERIALS AND METHODS: Between February 2009 and August 2019, 31 consecutives patients with 31 entirely intraparenchymal biopsy-proven renal cancers were treated with cryoablation under MRI-guidance in our institution, and were retrospectively included. There were 20 men and 11 women with a mean age of 68.5±12.5 (SD) (range: 40-91years). Patient, tumor- and procedure-related, and follow-up data were retrospectively collected and analyzed. Local recurrence free (LRFS), metastasis free (MFS), disease free (DFS), cancer specific (CSS), and overall survivals (OS) were calculated. RESULTS: Primary and secondary technical efficacy rates were 94% and 100%, respectively. Median follow-up was 27months. Seven (7/31; 23%) minor complications were noted in 7 patients. Patients showed a significant decline of the estimated glomerular filtration rate (eGFR) between baseline and nadir (mean basal eGFR 65.9±22.4 [SD] mL/min/1.73m2vs. mean nadir eGFR 52.8±26.0 [SD] mL/min/1.73m2; P<0.001), but only two showed a clinically significant renal function decline. Three-year estimates of primary and secondary LRFS, MFS, and DFS were 64% (95% confidence interval [CI]: 47-87%), 89% (95% CI: 78-99%), 83% (95% CI: 77-98%), and 45% (95% CI: 28-73%), respectively. No patients died due to renal cancer evolution (three-year CSS of 100%; 95% CI: 100-100%). One patient died 52months after the percutaneous treatment due to cryoablation-unrelated causes (three-year OS of 100%; 95% CI: 100-100%). CONCLUSION: MRI-guided percutaneous cryoablation for intraparenchymal renal cancer offers good oncologic outcomes with acceptable complication rates and renal function worsening.

Safety and Oncologic Outcomes of Magnetic Resonance Imaging-Guided Cryoablation of Renal Cell Carcinoma: A 10-Year Single-Center Experience.

OBJECTIVES: Magnetic resonance imaging guidance has been sporadically reported for renal tumor cryoablation (CA); therefore, clinical experience with this modality is still limited.The aim of this study is to retrospectively analyze our 10-year experience with renal tumor CA performed on a 1.5 T magnetic resonance imaging unit with the intent of reporting procedural safety and oncologic outcomes. MATERIALS AND METHODS: We included 143 patients (102 men; 41 women; median age, 73 years; range, 34-91 years) with 149 tumors (median size, 2.6 cm; range, 0.6-6.0 cm), treated between 2009 and 2019. Patient, tumor, procedure, and follow-up data were collected and analyzed. The Kaplan-Meier method was used to estimate local recurrence-free (LRFS), metastasis-free (MFS), disease-free (DFS), cancer-specific, and overall (OS) survival. Univariate and multivariate models were used to identify factors associated with complications, LRFS, MFS, DFS, and OS. RESULTS: The overall complication rate was 10.7% (16/149 tumors), with 1 major (1/149 [0.7%]; 95% confidence interval, 0.0%-3.7%) hemorrhagic complication. Other minor complications (15/149 [10.1%]; 95% confidence interval, 0.6%-16.1%) did not include any cases of injury to nearby organs. There were no factors associated with complications.Five-year estimates of LRFS (primary/secondary), MFS, DFS, cancer-specific survival, and OS were 82.8%/91.5%, 91.1%, 75.1%, 98.2%, and 89.6%, respectively. Increasing tumor size (hazard radio [HR], 1.8; P = 0.02) and intraparenchymal tumor location (HR, 5.6; P < 0.01) were associated with lower LRFS; increasing patient's age (HR, 0.5; P = 0.01), high tumor grade (HR, 23.3; P < 0.01) and non-clear-cell/nonpapillary histology (HR, 20.1; P < 0.01) with metastatic disease; and high tumor grade (HR, 3.2; P = 0.04) with lower DFS. CONCLUSION: Magnetic resonance imaging-guided CA of renal tumors is associated with acceptable morbidity and high survival estimates at 5-year follow-up. Given the absence of complications resulting from injuries to nearby organs, further studies are required to evaluate whether the potential reduced incidence of these adverse events justifies large-scale implementation of this interventional modality.

Diagnostic accuracy and safety of percutaneous MRI-guided biopsy of solid renal masses: single-center results after 4.5 years.

OBJECTIVES: To retrospectively evaluate diagnostic accuracy and complications of magnetic resonance imaging (MRI)-guided biopsy of radiologically indeterminate solid renal masses (RM). METHODS: Electronic records of all consecutive patients undergoing MRI-guided biopsy of solid RM (using free-breathing T2-BLADE and BEAT-IRTTT sequences) between April 2014 and October 2018 were reviewed; 101 patients (69 men, 32 women; median age 68 years; range 32-76) were included. Patient and RM characteristics, procedural details/complications, pathologic diagnosis, and clinical management were recorded. Diagnostic accuracy was calculated on an intention-to-diagnose basis. Diagnostic yield was also evaluated. Multi-variable analysis was performed for variables with p < .20, including patient age/sex; RM size/location/contact with vascular pedicle, RENAL score, number and total length of biopsy samples, and biopsy tract embolization, to determine factors associated with diagnostic samples, diagnostic accuracy, and complications. RESULTS: Median RM size was 2.4 cm (range 1-8.4 cm). There were 86 (85%; 95%CI 77-91%) diagnostic and 15 (15%; 95%CI 9-23%) non-diagnostic samples; 6/15 (40%) non-diagnostic biopsies were repeated with 50% malignancy rate. Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 96% (95%CI 89-99%), 100% (95%CI 77-100%), 100% (95%CI 95-100%), 82% (95%CI 57-96%), and 97% (95%CI 90-99%), respectively. Primary and secondary diagnostic yields were 85% (95%CI 77-91%) and 91% (95%CI 84-96%), respectively. Seven (7%; 95%CI 1-10%) complications were observed. No tested variables were associated with diagnostic samples, diagnostic accuracy, or complications. CONCLUSIONS: MRI-guided biopsy of solid RM is associated with high diagnostic accuracy and low complication rate. The technique might be helpful for inaccessible tumors. KEY POINTS: • MRI-guided biopsy of radiologically indeterminate solid renal masses (RM) appears safe, with a low rate of minor self-limiting hemorrhagic complications. • Diagnostic accuracy and primary/secondary diagnostic yield are high and appear similar to reported estimates for US- and CT-guided RM biopsy. • MRI guidance may be particularly useful for RM with poor conspicuity on US and CT, for relatively inaccessible tumors (e.g., tumors requiring double-oblique steep-angled approaches), and for young patients or those with renal failure.

Large nearly spherical ablation zones are achieved with simultaneous multi-antenna microwave ablation applied to treat liver tumours.

AIM: To investigate the shape and the volume of ablation zones obtained with microwave ablation (MWA) performed with multiple antennas in liver tumours. MATERIALS AND METHODS: Tumour volume, number of antennas, size (long diameter (Dl), along the antenna axis; short diameter (Ds), perpendicular to the antenna axis; vertical diameter (Dv), vertical to both Dl and Ds) and shape (roundness index (RI); 1 corresponds to a sphere) of the ablation zone, ablation volume, and complications were evaluated. RESULTS: Mean Dl, Ds, and Dv were 4.7 ± 1.4 cm, 3.9 ± 1.4 cm, and 3.8 ± 1.0 cm, respectively. Mean RIs (Ds/Dl, Dv/Dl, and Dv/Ds) were 0.83 ± 0.13, 0.83 ± 0.17, and 1.02 ± 0.23, respectively, without any difference between the mean RI obtained with the double (0.84 ± 0.01) and that with the triple-antenna (0.93 ± 0.13) approach (p = 0.25). Mean ablation volume was 41 ± 32 cm3 (vs. mean tumour volume 13 ± 10 cm3; range 1-40; p < 0.001). No complications were noted. CONCLUSIONS: Simultaneous multi-antenna MWA of liver tumours results in large nearly spherical ablation zones. KEY POINTS: • Simultaneous multi-antenna microwave ablation of liver tumours results in nearly spherical ablation zones. • The multi-antenna approach generates oversized ablation volumes compared with the target tumour volume. • The multi-antenna approach is safe.

The Added Diagnostic Value of 18F-Fluorodihydroxyphenylalanine PET/CT in the Preoperative Work-Up of Small Bowel Neuroendocrine Tumors.

BACKGROUND: The precise localization of the primary tumor and/or the identification of multiple primary tumors improves the preoperative work-up in patients with small bowel (SB) neuroendocrine tumor (NET). The present study assesses the diagnostic value of 18F-fluorodihydroxyphenylalanine (18F-FDOPA) positron emission tomography/computed tomography (PET/CT) during the preoperative wok-up of SB NETs. METHODS: Between January 2010 and June 2017, all consecutive patients with SB NETs undergoing preoperative 18F-FDOPA PET/CT and successive resection were analyzed. Preoperative work-up included computed tomography (CT), somatostatin receptor scintigraphy (SRS), and 18F-FDOPA PET/CT. Sensitivity and accuracy ratio for primary and multiple tumor detection were compared with data from surgery and pathology. RESULTS: There were 17 consecutive patients with SB NETs undergoing surgery. Nine patients (53%) had multiple tumors, 15 (88%) metastatic lymph nodes, 3 (18%) peritoneal carcinomatosis, and 9 patients (53%) liver metastases. A total of 70 SB NETs were found by pathology. Surgery identified the primary in 17/17 (100%) patients and recognized seven of 9 patients (78%) with multiple synchronous SB. Preoperatively, 18F-FDOPA PET/CT displayed a statistically significant higher sensitivity for primary tumor localization (100 vs. 23.5 vs. 29.5%) and multiple tumor detection (78 vs. 22 vs. 11%) over SRS and CT. Compared with pathology, 18F-FDOPA PET/CT displayed the highest accuracy ratio for number of tumor detected over CT and SRS (2.0 ± 2.2 vs. 0.4 ± 0.7 vs. 0.6 ± 1.5, p = 0.0003). CONCLUSION: 18F-FDOPA PET/CT significantly increased the sensitivity and accuracy for primary and multiple SB NET identification. 18F-FDOPA PET/CT should be included systematically in the preoperative work-up of SB NET.