Intraoperative MRI-derived volumetric ablation margins and initial correlation with local outcome after MRI-guided cryoablation of renal tumors.

PURPOSE: To assess volumetric ablation margins derived from intraoperative pre- and post-ablation MRI after magnetic resonance imaging (MRI)-guided percutaneous cryoablation of renal tumors and explore its correlation with local treatment success. METHODS: Retrospective analysis was performed on 30 patients (mean age 69y) who underwent percutaneous MRI-guided cryoablation between May 2014 and May 2020 for 32 renal tumors (size: 1.6-5.1 cm). Tumor and ice-ball volumes were segmented on intraprocedural pre- and post-ablation MR images using Software Assistant for Interventional Radiology (SAFIR) software. After MRI-MRI co-registration, the software automatically quantified the minimal treatment margin (MTM),defined as the smallest 3D distance between the tumor and ice-ball surface. Local tumor progression (LTP) after cryoablation was assessed on follow-up imaging. RESULTS: Median follow-up was 16 months (range: 1-58). Local control after cryoablation was achieved in 26 cases (81%) while LTP occurred in 6 (19%). The intended MTM of ≥5 mm was achieved in 3/32 (9%) cases. Median MTM was significantly smaller for cases with (- 7 mm; IQR:-10 to - 5) vs. without LTP (3 mm; IQR:2 to 4) (P < .001). All cases of LTP had a negative MTM. All negative treatment margins occurred in tumors > 3 cm. CONCLUSIONS: Determination of volumetric ablation margins from intraoperative MRI was feasible and may be useful in predicting local outcome after MRI-guided renal cryoablation. In our preliminary data, an intraoperative MRI-derived minimal margin extending at least 1 mm beyond the MRI-visible tumor led to local control and this was more difficult to achieve in tumors > 3 cm. Ultimately, online margin analysis may be a valuable tool to intraoperatively assess therapy success, but larger prospective studies are needed to establish a reliable threshold for clinical use.

[Pilonidal sinus of the penis]. / Een sinus pilonidalis aan de penis.

A 43-year-old man presented with a painful itching penile lesion. Examination revealed multiple fistulas with protruding hairs and surrounding induration. The urologist identified them as pilonidal sinuses and surgically performed debridement. Penile pilonidal sinus is a very rare differential diagnosis of balanoposthitis, epidermal cyst and penile carcinoma.

Kidney tumor diffusion-weighted magnetic resonance imaging derived ADC histogram parameters combined with patient characteristics and tumor volume to discriminate oncocytoma from renal cell carcinoma.

PURPOSE: To assess the ability to discriminate oncocytoma from RCC based on a model using whole tumor ADC histogram parameters with additional use of tumor volume and patient characteristics. METHOD: In this prospective study, 39 patients (mean age 65 years, range 28-79; 9/39 (23%) female) with 39 renal tumors (32/39 (82%) RCC and 7/39 (18%) oncocytoma) underwent multiparametric MRI between November 2014 and June 2018. Two regions of interest (ROIs) were drawn to cover both the entire tumor volume and a part of healthy renal cortex. ROI ADC maps were calculated using a mono-exponential model and ADC histogram distribution parameters were calculated. A logistic regression model was created using ADC histogram parameters, radiographic and patient characteristics that were significantly different between oncocytoma and RCC. A ROC curve of the model was constructed and the AUC, sensitivity and specificity were calculated. Furthermore, differences in intra-patient ADC histogram parameters between renal tumor and healthy cortex were calculated. A separate ROC curve was constructed to differentiate oncocytoma from RCC using statistically significant intra-patient parameter differences. RESULTS: ADC standard deviation (p = 0.008), entropy (p = 0.010), tumor volume (p = 0.012), and patient sex (p = 0.018) were significantly different between RCC and oncocytoma. The regression model of these parameters combined had an ROC-AUC of 0.91 with a sensitivity of 86% and specificity of 84%. Intra-patient difference in ADC 25th percentile (p < 0.01) and entropy (p = 0.030) combined had a ROC-AUC of 0.86 with a sensitivity and specificity of 86%, and 81%, respectively. CONCLUSION: A model combining ADC standard deviation and entropy with tumor volume and patient sex has the highest diagnostic value for discrimination of oncocytoma. Although less accurate, intra-patient difference in ADC 25th percentile and entropy between renal tumor and healthy cortex can also be used. Although the results of this preliminary study do not yet justify clinical use of the model, it does stimulate further research using whole tumor ADC histogram parameters.

Validation of a Web-Based Planning Tool for Percutaneous Cryoablation of Renal Tumors.

PURPOSE: To validate a simulation environment for virtual planning of percutaneous cryoablation of renal tumors. MATERIALS AND METHODS: Prospectively collected data from 19 MR-guided procedures were used for validation of the simulation model. Volumetric overlap of the simulated ablation zone volume (Σ) and the segmented ablation zone volume (S; assessed on 1-month follow-up scan) was quantified. Validation metrics were DICE Similarity Coefficient (DSC; the ratio between twice the overlapping volume of both ablation zones divided by the sum of both ablation zone volumes), target overlap (the ratio between the overlapping volume of both ablation zones to the volume of S; low ratio means S is underestimated), and positive predictive value (the ratio between the overlapping volume of both ablation zones to the volume of Σ; low ratio means S is overestimated). Values were between 0 (no alignment) and 1 (perfect alignment), a value > 0.7 is considered good. RESULTS: Mean volumes of S and Σ were 14.8 cm3 (± 9.9) and 26.7 cm3 (± 15.0), respectively. Mean DSC value was 0.63 (± 0.2), and ≥ 0.7 in 9 cases (47%). Mean target overlap and positive predictive value were 0.88 (± 0.11) and 0.53 (± 0.24), respectively. In 17 cases (89%), target overlap was ≥ 0.7; positive predictive value was ≥ 0.7 in 4 cases (21%) and < 0.6 in 13 cases (68%). This indicates S is overestimated in the majority of cases. CONCLUSION: The validation results showed a tendency of the simulation model to overestimate the ablation effect. Model adjustments are necessary to make it suitable for clinical use.

Follow-up imaging after cryoablation of clear cell renal cell carcinoma is feasible using single photon emission computed tomography with 111In-girentuximab.

PURPOSE: Detection of residual or recurrent vital renal tumor on follow-up (FU) cross-sectional imaging after ablative therapy is challenging. The specific and high expression levels of carbonic anhydrase IX (CAIX) in clear cell renal cell carcinoma (ccRCC) makes it a suitable target for imaging using radiolabeled anti-CAIX antibody girentuximab. The objective of this study was to evaluate the feasibility of targeted FU imaging 1 month after cryoablation of ccRCC using single photon emission computed tomography (SPECT) after 111In-labeled girentuximab administration. METHODS: In this prospective study 16 patients underwent 111In-girentuximab-SPECT before MR-guided renal cryoablation between February 2015 and September 2018. In case of tumor targeting 111In-girentuximab-SPECT was repeated 1 month following MR-guided cryoablation. Presence of residual or recurrent vital tumor was assessed on contrast-enhanced cross-sectional imaging during further FU. The standard FU imaging protocol consisted of MRI/CT scans at 1, 3, 6, 12, and 18 months and annually thereafter. RESULTS: A total of 10 (63%) patients showed positive tumor targeting on 111In-girentuximab-SPECT before cryoablation and 9 ( 56%) were eligible to undergo FU SPECT. Of the 9 111In-girentuximab-SPECT FU scans, 8 (89%) were considered negative. One (11%) scan showed uptake suggestive for residual vital tumor. Six months after treatment, FU CT showed contrast enhancement suggestive for residual/recurrent disease in the ablated zone at the site of the 111In-girentuximab uptake after treatment. During a mean FU of 21 months (range 1-33) no other cases with residual/recurrent disease were detected. CONCLUSION: FU imaging with 111In-girentuximab-SPECT is feasible after ccRCC cryoablation and may contribute to early detection of residual or recurrent disease.

MRI as a tool to assess surgical margins and pseudocapsule features directly following partial nephrectomy for small renal masses.

PURPOSE: To evaluate the feasibility of ex vivo 7T MRI to assess surgical margins (SMs) and pseudocapsule (PC) features after partial nephrectomy (PN). MATERIALS AND METHODS: In this prospective, IRB-approved study, seven patients undergoing a PN for nine tumours between November 2014 and July 2015 were included for analysis after obtaining informed consent. MRI of the specimen was acquired using a 7T small bore scanner. The imaging protocol consisted of anatomical T1-, T2- and diffusion-weighted imaging. After formalin fixation, specimens were cut for pathology work-up in the same orientation as the MR images were obtained. The entire specimen was processed into H&E slides that were digitally scanned, annotated and correlated with radiological findings for negative SMs, PC presence, PC continuity and extra-PC-extension (EPCE). Sensitivity and specificity of MRI for assessment of these endpoints were calculated. RESULTS: The sensitivity and specificity for assessment of the SM were 100% and 75%, respectively. Two false-positive outcomes were reported, both in case of EPCE and a SM ≤0.5 mm. For the presence of a PC, sensitivity and specificity were 100% and 33%, respectively. Two false-positive scans with anatomical structures mimicking the presence of a PC occurred. If a PC was present, continuity and EPCE were assessed with a sensitivity and specificity of 75% and 100% and 67% and 100%, respectively. CONCLUSION: Ex vivo 7T MRI is a feasible tool for perioperative evaluation of SMs, and if present, PC features after PN. This may facilitate maximal sparing of renal parenchyma without compromising oncological outcomes. KEY POINTS: • Ex vivo MRI may contribute to improvement of negative surgical margins during partial nephrectomy. • Due to the assessment of surgical margins within a limited time span from obtaining the partial nephrectomy specimen, surgery for more complex tumours is possible with maximum sparing of healthy renal parenchyma without compromising oncological outcomes. • The intra operative assessment of pseudocapsule continuity along the resection margin enables maximal sparing of healthy renal parenchyma without delayed diagnosis of incomplete resection.

Diagnostic Imaging for Solid Renal Tumors: A Pictorial Review.

The prognosis of renal tumors depends on histologic subtype. The increased use of abdominal imaging has resulted in an increase in the number of small renal incidentaloma in recent decades. Of these incidentally discovered tumors, 20% are benign lesions warranting conservative management, but most are renal cell carcinomas that warrant a more aggressive therapeutic approach due to their malignant potential. Dedicated diagnostic renal imaging is important for characterization of renal tumors to facilitate treatment planning. This review discusses the ability to detect and differentiate renal cell carcinoma subtypes, angiomyolipoma and oncocytoma based on ultrasound imaging, computed tomography, multiparametric magnetic resonance, and nuclear imaging.

Percutaneous MR Imaging-Guided Cryoablation of Small Renal Masses in a 3-T Closed-Bore MR Imaging Environment: Initial Experience.

PURPOSE: To assess the feasibility of percutaneous magnetic resonance (MR) imaging-guided cryoablation of small renal masses (SRMs) in a 3-T environment and to evaluate intraprocedural imaging, procedural safety, and initial outcomes. MATERIALS AND METHODS: The analysis included 9 patients (4 men; median age, 72 y; range, 70-82 y) with 9 SRMs (diameter, 12-30 mm). Lesions underwent biopsy, and cryoneedles were inserted under ultrasound guidance. Verification of needle positions and ice-ball monitoring were performed by T1-weighted volumetric interpolated breath-hold examination and T2-weighted half-Fourier acquired single-shot turbo spin-echo sequences. On image analysis, needle positioning was considered appropriate if the target lesion border was visible, the needle tip was inside the target lesion, and the ice ball was expected to cover the target lesion with a 5-mm margin. If these criteria could not be assessed, imaging was considered inadequate. Technical success was defined as tumor coverage with a 5-mm margin and no residual disease on 1-mo follow-up MR imaging. RESULTS: Median total procedure time was 170 min (range, 135-193 min). Intraoperative imaging allowed adequate needle visualization in 67% of acquired scans (4 of 7 T1-weighted and 6 of 8 T2-weighted). Appropriate positioning of two or three needles used for each procedure was confirmed in all cases on T1- or T2-weighted imaging. Ice-ball formation was adequately visualized in all patients. Technical success rate was 100%. No local recurrences were detected on follow-up imaging at a median of 12 mo (range, 3-22 mo). CONCLUSIONS: Percutaneous MR-guided cryoablation of SRMs in a 3-T MR imaging environment is safe and feasible, showing adequate intraoperative imaging capabilities with promising short-term clinical outcomes.

Phase 2 Study of Lutetium 177-Labeled Anti-Carbonic Anhydrase IX Monoclonal Antibody Girentuximab in Patients with Advanced Renal Cell Carcinoma.

UNLABELLED: Despite advances in the treatment of metastatic clear cell renal cell carcinoma (ccRCC), there is still an unmet need in the treatment of this disease. A phase 2 radioimmunotherapy (RIT) trial with lutetium 177 ((177)Lu)-girentuximab was initiated to evaluate the efficacy of this approach. In this nonrandomized single-arm trial, patients with progressive metastatic ccRCC who met the inclusion criteria received 2405 MBq/m(2) of (177)Lu-girentuximab intravenously. In the absence of persistent toxicity and progressive disease, patients were eligible for retreatment after 3 mo with 75% of the previous activity dose. A total of 14 patients were included. After the first therapeutic infusion, eight patients (57%) had stable disease (SD) and one (7%) had a partial regression. The treatment was generally well tolerated but resulted in grade 3-4 myelotoxicity in most patients. After the second cycle, continued SD was observed in five of six patients, but none were eligible for retreatment due to prolonged thrombocytopenia. In conclusion, RIT with (177)Lu-girentuximab resulted in disease stabilization in 9 of 14 patients with progressive metastatic ccRCC, but myelotoxicity prevented retreatment in some patients. PATIENT SUMMARY: We investigated the efficacy of lutetium 177-girentuximab radioimmunotherapy in patients with metastatic kidney cancer. The treatment resulted in disease stabilization in 9 of 14 patients. The main toxicity was prolonged low blood cell counts. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02002312 (https://clinicaltrials.gov/ct2/show/NCT02002312).

The blind spots in follow-up after nephrectomy or nephron-sparing surgery for localized renal cell carcinoma.

PURPOSE: This study was conducted to identify time to and type of recurrence in relation to scheduled follow-up (FU) imaging after nephrectomy or nephron-sparing surgery for localized renal cell carcinoma (RCC). Using this information, future guidelines could improve the early detection of metastases. METHODS: Measured from moment of treatment, all recurrences after (partial) nephrectomy performed between 2000 and 2010 were categorized as being detected early (<6 months), late (>5 year for T1/T2 and >10 year for T3/T4), or intermediate (time within those two) based on European Association of Urology (EAU) guidelines. Also symptomatic presentation was screened. RESULTS: Recurrent disease developed in 80 of 396 patients after (partial) tumor nephrectomy. Mean time to recurrence in months was 56 (n = 21) for T1, 24 (n = 18) for T2, 21 (n = 38) for T3, and 11 (n = 2) for T4 tumors. Detection of early recurrence occurred in 22 patients (28%), of which 20 (91%) were T2-T4 tumors. In 10 (48%) of T1 tumors, late recurrence was found. Of the patients with symptoms due to recurrence, 65% (17/26) were detected outside the FU surveillance protocol (P = 0.01). CONCLUSION: A more intensive FU the first 6 months after nephrectomy for T2-T4 and FU imaging ≥5 years after surgery for T1 tumors might improve early and asymptomatic detection of recurrent disease after nephrectomy for RCC.

Outcome of endovascular reintervention for significant stenosis at infrainguinal bypass anastomoses.

OBJECTIVE: The durability of an infrainguinal bypass may be hampered by development of stenosis at the anastomoses. We describe the patency of percutaneous transluminal angioplasty (PTA) of these anastomotic stenoses. METHODS: Any venous or prosthetic infrainguinal bypass with a hemodynamically significant anastomotic stenosis, symptomatic or asymptomatic, was considered a bypass at risk (BAR) for occlusion. All BARs undergoing PTA in two large vascular referral centers between January 2005 and December 2010 were retrospectively reviewed. Procedural success was defined as <30% residual stenosis. Primary end points were primary, assisted primary, and secondary patency rates. RESULTS: Included were 43 patients with 43 BARs (31 venous, 11 prosthetic, and 1 unknown conduit; 19 supragenicular and 24 infragenicular). Mean follow-up was 17 months (range, 0-57 months). Procedures constituted 48 interventions for proximal (n = 13), distal (n = 25), or combined (n = 5) anastomotic stenoses. Procedural success was 96%. The primary, assisted primary, and secondary patency rates were 58%, 85%, and 88%, respectively, at 2 years. CONCLUSIONS: PTA for infrainguinal BAR due to anastomotic stenosis is technically feasible with acceptable durability. PTA for these anastomotic stenoses may be considered a safe option as the first-line treatment.