Is cryoablation a valid option for renal cell carcinomas in direct contact with critical organs?

PURPOSE: This study aimed to assess the outcomes of percutaneous cryoablation (PCA) for renal cell carcinomas (RCCs) contacting critical organs without intervening fat tissue. MATERIAL AND METHODS: Twenty-three patients with 24 RCCs (mean size, 28.8 mm) contacting critical organs on preprocedural images were included. The organ displacement techniques, technical success, efficacy, and adverse events per Clavien-Dindo classification were retrospectively reviewed. RESULTS: The organs contacting the RCCs included the colon (n = 16), pancreas (n = 3), duodenum (n = 3), small intestine (n = 1), and stomach (n = 1). In all procedures, hydrodissection was conducted, and probe traction was additionally utilized in one to displace organs. Two procedures were terminated with an insufficient ice-ball margin (<6 mm) due to recurring proximity of the colon or thermal sink effect by renal hilar vessels, yielding a technical success rate of 91.6% (22/24). No severe adverse events were noted. All patients were alive without any metastases during a median follow-up of 34.4 months. The primary and secondary technical efficacy rates were 91.6% (22/24) and 95.8% (23/24) of tumors, respectively. CONCLUSION: PCA can be a valid option for RCCs contacting critical organs with a good safety profile and sufficient technical efficacy.

Automated Feeder-Detection Software for Renal Cell Carcinoma Embolization: A Retrospective Evaluation of Detection Rate Using Transarterial Time-Resolved Computed Tomography Angiography.

PURPOSE: To evaluate the detection rate of feeding arteries in renal cell carcinoma with automated feeder-detection software and determine the optimal imaging phase for accurate feeder detection with transarterial time-resolved computed tomography angiography. MATERIALS AND METHODS: The performance of automated feeder-detection software was retrospectively evaluated using transarterial renal time-resolved computed tomography angiography images of 15 renal cell carcinomas (mean size, 22.1 mm); the images were obtained via the renal artery using a hybrid angio-CT system with 320-row computed tomography, across nine phases with 0.5-s intervals over a contrast delay time of 1.0-5.0 s. Automated feeder-detection software was applied to each phase in all tumors (135 image series in total). The feeder-detection rate (i.e., sensitivity) in each phase was evaluated, and the number of false feeders demonstrated by the software was counted for each tumor. RESULTS: A total of 22 feeders were identified. The feeder-detection rate was the highest (95.5% [21/22]) at delay times of 1.5 s and 2.0 s and lower in later phases. At delay times of 1.0 s and 1.5 s, the software demonstrated no or only a few (≤ 3) false feeders in 93.3% (14/15) of the tumors. In later phases, however, many (≥ 4) false feeders were observed in > 50% of tumors. CONCLUSION: The automated feeder-detection software showed a favorable feeder-detection rate and may be useful in transarterial embolization for renal cell carcinoma. The optimal delay time to avoid the demonstration of false feeders and achieve a high detection accuracy was 1.5 s. LEVEL OF EVIDENCE IV: Case Series.

[A Case of Refractory Lymphatic Leakage after Robot-Assisted Radical Cystectomy].

A 78-year-old male visited the referring hospital because of asymptomatic gross hematuria. The patient was diagnosed with bladder cancer, clinical stage T3aN2M0, after multiple tumors were found in the bladder by cystoscopy and bilateral obturator lymph node metastases were found by contrast-enhanced thoracoabdominal-pelvic computed tomography. After neoadjuvant chemotherapy, the patient underwent robot-assisted radical cystectomy and pelvic lymph node dissection, followed by bilateral ureterocutaneostomy for urinary diversion. Postoperatively, the drainage volume from the pelvic drain ranged from 1,000 to 3,000 ml/day. We suspected lymphatic leakage based on the results of biochemical tests of the drainage fluid. Lymphangiography was conducted to confirm the diagnosis of lymphatic leakage, and lymphatic embolization was performed simultaneously. The patient underwent lymphangiography four times, but the lymphatic leakage persisted. Surgical treatment was considered, and lymphangioscintigraphy was conducted to search for areas of lymphatic leakage that could not be delineated by lymphangiography. Ascites decreased significantly after lymphangioscintigraphy.

Comparison of image quality, arterial depiction, and radiation dose between two rapid kVp-switching dual-energy CT scanners in CT angiography at 40-keV.

PURPOSE: To compare the quantitative parameters and qualitative image quality of dual-energy CT angiography (CTA) between two rapid kVp-switching dual-energy CT scanners. MATERIALS AND METHODS: Between May 2021 and March 2022, 79 participants underwent whole-body CTA using either Discovery CT750 HD (Group A, n = 38) or Revolution CT Apex (Group B, n = 41). All data were reconstructed at 40-keV and with adaptive statistical iterative reconstruction-Veo of 40%. The two groups were compared in terms of CT numbers of the thoracic and abdominal aorta, and the iliac artery, background noise, signal-to-noise ratio (SNR) of the artery, CT dose-index volume (CTDIvol), and qualitative scores for image noise, sharpness, diagnostic acceptability, and arterial depictions. RESULTS: The median CT number of the abdominal aorta (p = 0.04) and SNR of the thoracic aorta (p = 0.02) were higher in Group B than in Group A, while no difference was observed in the other CT numbers and SNRs of the artery (p = 0.09-0.23). The background noises at the thoracic (p = 0.11), abdominal (p = 0.85), and pelvic (p = 0.85) regions were comparable between the two groups. CTDIvol was lower in Group B than in Group A (p = 0.006). All qualitative scores were higher in Group B than in Group A (p < 0.001-0.04). The arterial depictions were nearly identical in both two groups (p = 0.005-1.0). CONCLUSION: In dual-energy CTA at 40-keV, Revolution CT Apex improved qualitative image quality and reduced radiation dose.

Complications of Percutaneous Cryoablation for Renal Tumors and Methods for Avoiding Them.

Percutaneous cryoablation of renal tumors is widely used because of its high efficacy and safety. This high safety can be attributed, at least in part, to the visibility of the ablated area as an "ice ball". This therapy has fewer complications (incidence, 0-7.2%) and is less invasive than surgery. Minor bleeding is inevitable in most kidney-related procedures, and indeed the most common complication of this therapy is bleeding (hematoma and hematuria). However, patients require treatment such as transfusion or transarterial embolization in only 0-4% of bleeding cases. Various other complications such as ureteral or collecting system injury, bowel injury, nerve injury, skin injury, infection, pneumothorax, and tract seeding also occur, but they are usually minor and asymptomatic. However, operators should know and avoid the various complications associated with this therapy. This study aimed to summarize the complications of percutaneous cryoablation for renal tumors and provide some techniques for achieving safe procedures.

Renal cryoablation combined with prior transcatheter arterial embolization in non-dialysis patients with stage 4 or 5 chronic kidney disease: a retrospective study.

PURPOSE: To retrospectively evaluate cryoablation combined with prior transcatheter arterial embolization (TAE) for renal cell carcinoma (RCC) in non-dialysis patients with stage 4 or 5 chronic kidney disease (CKD). MATERIALS AND METHODS: Patients with stage 4 or 5 CKD undergoing TAE and cryoablation for RCC between May 2012 and October 2021 were included. TAE was selectively performed using iodized oil with absolute ethanol or gelatin sponge 1-14 days before cryoablation. Local efficacy, safety, and changes in renal function were evaluated. RESULTS: Nine patients (seven men and two women; median age, 64 years; range 52-88 years) with nine RCCs (mean diameter, 3.0 ± 1.0 cm; range 1.7-4.7 cm) were included. The mean pre-treatment estimated glomerular filtration rate (eGFR) was 24.2 ± 5.6 ml/min/1.73 m2 (range 10.4-29.2 ml/min/1.73 m2). The mean amount of contrast medium used in TAE was 58 ± 29 ml (range 40-128 ml). Except in one patient (grade 3 pyelonephritis), no grade ≥ 3 complications occurred. During the follow-up period (median, 18 months; range 7-54 months), no local tumor progression occurred. In two patients with pre-treatment eGFR of < 20 ml/min/1.73 m2, hemodialysis was initiated at 3 and 19 months after cryoablation. At their last follow-up, the remaining seven patients showed a decrease of 6.2 ± 5.3 ml/min/1.73 m2 (range 0.7-17.2 ml/min/1.73 m2) in their eGFR. CONCLUSION: Cryoablation combined with TAE for RCC in non-dialysis patients with stage 4 or 5 CKD was effective and safe, with an acceptable impact on renal function.

Determination of arterial invasion in pancreatic ductal adenocarcinoma: what is the best diagnostic criterion on CT?

OBJECTIVES: To investigate the diagnostic performance and interobserver variability in the determination of arterial invasion in pancreatic ductal adenocarcinoma (PDAC) and determine the best CT imaging criterion. METHODS: We retrospectively evaluated 128 patients with PDAC (73 men and 55 women) who underwent preoperative contrast-enhanced CT. Five board-certified radiologists (expert) and four fellows (non-expert]) independently assessed the arterial invasion (celiac, superior mesenteric, splenic, and common hepatic arteries) using a 6-point score: 1, no tumor contact; 2, hazy attenuation ≤ 180°; 3, hazy attenuation > 180°; 4, solid soft tissue contact ≤ 180°; 5, solid soft tissue contact > 180°; and 6, contour irregularity. ROC analysis was performed to evaluate the diagnostic performance and determine the best diagnostic criterion for arterial invasion, with pathological or surgical findings as references. Interobserver variability was assessed using Fleiss's ĸ statistics. RESULTS: Among the 128 patients, 35.2% (n = 45/128) received neoadjuvant treatment (NTx). Solid soft tissue contact ≤ 180° was the best diagnostic criterion for arterial invasion as defined by the Youden Index both in patients who did and did not receive NTx (sensitivity, 100% vs. 100%; specificity, 90% vs. 93%; and AUC, 0.96 vs. 0.98, respectively). Interobserver variability among the non-expert was not inferior to that among the expert (ĸ = 0.61 vs 0.61; p = .39 and ĸ = 0.59 vs 0.51; p < .001 in patients treated with and without NTx, respectively). CONCLUSIONS: Solid soft tissue contact ≤ 180° was the best diagnostic criterion for the determination of arterial invasion in PDAC. Considerable interobserver variability was seen among the radiologists. KEY POINTS: • Solid soft tissue contact ≤ 180° was the best diagnostic criterion for the determination of arterial invasion in pancreatic ductal adenocarcinoma. • Interobserver agreement among non-expert radiologists was almost comparable to that among expert radiologists.

Intranodal dynamic contrast-enhanced CT lymphangiography and dynamic contrast-enhanced MR lymphangiography in microminipig.

OBJECTIVES: To evaluate the feasibility and image quality of intranodal dynamic contrast-enhanced CT lymphangiography (DCCTL) and dynamic contrast-enhanced MR lymphangiography (DCMRL) in microminipigs. METHODS: Our institution's committee for animal research and welfare provided approval. Three microminipigs underwent DCCTL and DCMRL after inguinal lymph node injection of 0.1 mL/kg contrast media. Mean CT values on DCCTL and signal intensity (SI) on DCMRL were measured at the venous angle and thoracic duct (TD). The contrast enhancement index (CEI; increase in CT values pre- to post-contrast) and signal intensity ratio (SIR; SI of lymph divided by SI of muscle) were evaluated. The morphologic legibility, visibility, and continuity of lymphatics were qualitatively evaluated using a 4-point scale. Two microminipigs underwent DCCTL and DCMRL after lymphatic disruption and the detectability of lymphatic leakage was evaluated. RESULTS: The CEI peaked at 5-10 min in all microminipigs. The SIR peaked at 2-4 min in two microminipigs and at 4-10 min in one microminipig. The peak CEI and SIR values were 235.6 HU and 4.8 for venous angle, 239.4 HU and 2.1 for upper TD, and 387.3 HU and 2.1 for middle TD. The visibility and continuity of upper-middle TD scores were 4.0 and 3.3-3.7 for DCCTL, and 4.0 and 4.0 for DCMRL. In the injured lymphatic model, both DCCTL and DCMRL demonstrated lymphatic leakage. CONCLUSIONS: DCCTL and DCMRL in a microminipig model enabled excellent visualization of central lymphatic ducts and lymphatic leakage, indicating the research and clinical potential of both modalities. KEY POINTS: • Intranodal dynamic contrast-enhanced computed tomography lymphangiography showed a contrast enhancement peak at 5-10 min in all microminipigs. • Intranodal dynamic contrast-enhanced magnetic resonance lymphangiography showed a contrast enhancement peak at 2-4 min in two microminipigs and at 4-10 min in one microminipig. • Both intranodal dynamic contrast-enhanced computed tomography lymphangiography and dynamic contrast-enhanced magnetic resonance lymphangiography demonstrated the central lymphatic ducts and lymphatic leakage.

Evidence on percutaneous radiofrequency and microwave ablation for liver metastases over the last decade.

PURPOSE: This review aimed to summarize the treatment outcomes of percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) for metastatic liver tumors based on the findings of published studies over the last decade. MATERIALS AND METHODS: Literature describing the survival outcomes of ablation therapy for liver metastases was explored using the PubMed database on April 26, 2022, and articles published in 2012 or later were selected. The included studies met the following criteria: (i) English literature, (ii) original clinical studies, and (iii) literature describing overall survival (OS) of thermal ablation for metastatic liver tumors. All case reports and cohort studies with fewer than 20 patients and those that evaluated ablation for palliative purposes were excluded. RESULTS: RFA was the most commonly used method for ablation, while MWA was used in several recent studies. RFA and MWA for liver metastases from various primary tumors have been reported; however, majority of the studies focused on colorectal cancer. The local control rate by RFA and MWA varied widely among the studies, ranging approximately 50-90%. Five-year survival rates of 20-60% have been reported following ablation for colorectal liver metastases by a number of studies, and several reports of 10-year survival rates were also noted. CONCLUSION: Comparative studies of local therapies for colorectal liver metastases demonstrated that RFA provides comparable survival outcomes to surgical metastasectomy and stereotactic body radiation therapy.

Up-to-date evidence on image-guided thermal ablation for metastatic lung tumors: a review.

The aim of this review was to summarize the latest evidence on image-guided thermal ablation therapies for lung metastases. PubMed was used to search for relevant articles that reported the oncological outcomes of thermal ablation for metastatic lung tumors, and those published in 2010 or later were selected for review. Ablative therapies were applied for lung metastases from various types of primary tumors, but most commonly colorectal ones. Radiofrequency ablation (RFA) was the most evaluated technique, followed by microwave ablation (MWA). The local control rates of ablative therapies were generally favorable, approximately 80-90% in many studies. Representative studies demonstrated promising overall survival rates of approximately 50% or higher 5 years after ablation for lung metastases from colorectal cancer or mixed types of primary tumors. Nevertheless, the survival outcomes varied depending on the type of primary tumor and background factors of patients such as other metastases and comorbidities. Several studies had aimed to compare the outcomes of various ablative therapies such as RFA, MWA, and cryoablation; however, conclusive data are not yet available to determine the most appropriate ablation modality for lung metastases. Further data accumulation is needed, especially for long-term outcomes and comparisons with other therapies.

Radiological Arterial Anatomy in Mature Microminipigs as a Pre-clinical Research Model in Interventional Radiology.

PURPOSE: To define the radiological arterial anatomy in mature microminipigs as a pre-clinical research animal model in interventional radiology. MATERIALS AND METHODS: Five female microminipigs (weighing 20.9 ± 2.9 kg) were used in this study. Under general anesthesia, computed tomography (CT) angiography was performed using a 16-slice CT scanner. CT was performed 12 s after initiation of an intravenous injection of 40 ml of nonionic contrast media at 3.0 ml/second using a power injector. The transverse CT angiography images were evaluated using a digital imaging and communication in medicine viewer, and the diameters of the following 41 arteries were measured.: ascending aorta, descending aorta, thoracoabdominal aorta, abdominal aorta, pulmonary artery trunk, both pulmonary, brachiocephalic artery, short common bicarotid, both common carotid artery, subclavian, bronchial, internal mammary, celiac, common hepatic, left lateral hepatic, middle hepatic, left hepatic, gastroduodenal, cranial duodenopancreatic, splenic, left gastric, cranial mesenteric, ileocolic , bilateral colic artery, caudal mesenteric, cranial rectal, renal, both external iliac arteries, internal iliac common trunk, and both internal iliac and femoral arteries. RESULTS: The microminipigs' vascular anatomy was the same as domestic pig anatomy and similar to human anatomy. The diameter of the aorta (ascending to abdominal) was 17.1-7.0 mm, iliac and femoral arteries (internal iliac common trunk to femoral artery): 5.5-3.8 mm, pulmonary arteries: 9.3-14.7 mm, and major first aortic branches (e.g., celiac or brachiocephalic artery): 2.2-9.2 mm. CONCLUSION: This study defined the microminipig arterial anatomy in the trunk.

Deep learning image reconstruction algorithm for pancreatic protocol dual-energy computed tomography: image quality and quantification of iodine concentration.

OBJECTIVES: To evaluate the image quality and iodine concentration (IC) measurements in pancreatic protocol dual-energy computed tomography (DECT) reconstructed using deep learning image reconstruction (DLIR) and compare them with those of images reconstructed using hybrid iterative reconstruction (IR). METHODS: The local institutional review board approved this prospective study. Written informed consent was obtained from all participants. Thirty consecutive participants with pancreatic cancer (PC) underwent pancreatic protocol DECT for initial evaluation. DECT data were reconstructed at 70 keV using 40% adaptive statistical iterative reconstruction-Veo (hybrid-IR) and DLIR at medium and high levels (DLIR-M and DLIR-H, respectively). The diagnostic acceptability and conspicuity of PC were qualitatively assessed using a 5-point scale. IC values of the abdominal aorta, pancreas, PC, liver, and portal vein; standard deviation (SD); and coefficient of variation (CV) were calculated. Qualitative and quantitative parameters were compared between the hybrid-IR, DLIR-M, and DLIR-H groups. RESULTS: The diagnostic acceptability and conspicuity of PC were significantly better in the DLIR-M group compared with those in the other groups (p < .001-.001). The IC values of the anatomical structures were almost comparable between the three groups (p = .001-.9). The SD of IC values was significantly lower in the DLIR-H group (p < .001) and resulted in the lowest CV (p < .001-.002) compared with those in the hybrid-IR and DLIR-M groups. CONCLUSIONS: DLIR could significantly improve image quality and reduce the variability of IC values than could hybrid-IR. KEY POINTS: Image quality and conspicuity of pancreatic cancer were the best in DLIR-M. DLIR significantly reduced background noise and improved SNR and CNR. The variability of iodine concentration was reduced in DLIR.

Magnetic resonance cholangiopancreatography using optimized integrated combination with parallel imaging and compressed sensing technique.

PURPOSE: To assess the combined parallel imaging (PI) and optimized integrated compressed sensing technique (prototype Compressed SENSE) for magnetic resonance cholangiopancreatography (MRCP) compared with conventional MRCP. METHODS: This prospective study was approved by our Institutional Review Board, and all patients provided written informed consent. A total of 56 consecutive patients (27 men and 29 women; mean age 67.2 years) underwent breath-hold three-dimensional (3D) MRCP with PI alone (BH-MRCP; acquisition time, 23 s), respiratory-triggered 3D MRCP with PI alone (RT-MRCP; 201 s) and respiratory-triggered 3D MRCP with Compressed SENSE (RT-MRCPcs; 45 s). Relative duct-to-periductal contrast ratios (RCs) of the pancreaticobiliary ducts were calculated for quantitative image analyses. Two radiologists graded the visibility of the pancreaticobiliary ducts, pancreatic cystic lesion, motion artifact, and overall image quality using a five-point rating scale for qualitative image analyses. Theses qualitative and quantitative measurements were then compared among the three sequences. RESULTS: RCs of the common bile duct, right hepatic duct (RHD), left hepatic duct (LHD), and main pancreatic duct at the pancreatic head, body, and tail segments, were significantly higher RT-MRCP, followed by RT-MRCPcs and BH-MRCP (P < 0.001). The visibility of the peripheral RHD and LHD was slightly better in RT-MRCP than in RT-MRCPcs and BH-MRCP (P < 0.001). The visibility of other pancreaticobiliary ducts, pancreatic cystic lesion, motion artifact, and overall image quality were almost comparable among three sequences. CONCLUSION: The acquisition time was markedly reduced in RT-MRCPcs compared with conventional RT-MRCP while there were significant differences in both quantitative and qualitative analyses, the differences were small enough that the reduced acquisition time makes up for it.