Deep Learning Based on MRI for Differentiation of Low- and High-Grade in Low-Stage Renal Cell Carcinoma.

Pretreatment determination of renal cell carcinoma aggressiveness may help to guide clinical decision-making. PURPOSE: To evaluate the efficacy of residual convolutional neural network using routine MRI in differentiating low-grade (grade I-II) from high-grade (grade III-IV) in stage I and II renal cell carcinoma. STUDY TYPE: Retrospective. POPULATION: In all, 376 patients with 430 renal cell carcinoma lesions from 2008-2019 in a multicenter cohort were acquired. The 353 Fuhrman-graded renal cell carcinomas were divided into a training, validation, and test set with a 7:2:1 split. The 77 WHO/ISUP graded renal cell carcinomas were used as a separate WHO/ISUP test set. FIELD STRENGTH/SEQUENCE: 1.5T and 3.0T/T2 -weighted and T1 contrast-enhanced sequences. ASSESSMENT: The accuracy, sensitivity, and specificity of the final model were assessed. The receiver operating characteristic (ROC) curve and precision-recall curve were plotted to measure the performance of the binary classifier. A confusion matrix was drawn to show the true positive, true negative, false positive, and false negative of the model. STATISTICAL TESTS: Mann-Whitney U-test for continuous data and the chi-square test or Fisher's exact test for categorical data were used to compare the difference of clinicopathologic characteristics between the low- and high-grade groups. The adjusted Wald method was used to calculate the 95% confidence interval (CI) of accuracy, sensitivity, and specificity. RESULTS: The final deep-learning model achieved a test accuracy of 0.88 (95% CI: 0.73-0.96), sensitivity of 0.89 (95% CI: 0.74-0.96), and specificity of 0.88 (95% CI: 0.73-0.96) in the Fuhrman test set and a test accuracy of 0.83 (95% CI: 0.73-0.90), sensitivity of 0.92 (95% CI: 0.84-0.97), and specificity of 0.78 (95% CI: 0.68-0.86) in the WHO/ISUP test set. DATA CONCLUSION: Deep learning can noninvasively predict the histological grade of stage I and II renal cell carcinoma using conventional MRI in a multiinstitutional dataset with high accuracy. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2.

Long-term outcomes of a benign biliary stricture protocol.

PURPOSE: To evaluate long-term outcomes of a structured protocol for percutaneous treatment of benign biliary stricture. MATERIALS AND METHODS: Seventy-one patients (37 men, 34 women; mean age, 54 y; age range, 23-84 y) entered the protocol, which consisted of staged upsizing of internal/external biliary catheters, balloon dilation (nominally 8 mm), and prolonged stent treatment (6 mo) at maximal catheter size (nominally 18 F). It concluded with a capping trial and catheter removal if the stricture remained patent. Fifty-three patients completed the protocol and 18 did not (6 died, 6 underwent alternative treatment, 4 were lost to follow-up, and 2 underwent repeat transplantation). Stricture features, treatment parameters, complications, and outcomes were reviewed, and Kaplan-Meier analysis was conducted. RESULTS: Strictures were anastomotic in 45 patients (64%), intrahepatic in 14 (20%), extrahepatic in 7 (10%), and multiple (intra- and extrahepatic) in 5 (7%). A right-sided approach was used in 47 patients (66%) patients, a left-sided approach in 18 (25%), and a bilateral approach in 6 (9%). Forty-six patients who entered the protocol (65%) and 46 patients who completed the protocol (87%) showed stricture patency. Four of 7 patients in whom a capping trial failed underwent surgical revision, 2 required chronic biliary drainage, and 1 received a metal stent. Follow-up (range, 0-12 y; mean, 4.7 y) was obtained for 42 of 53 patients who completed the protocol (79%). Kaplan-Meier analysis showed stricture patency probabilities of 84% at 1 year after treatment, 78% at 2 years, 74% at 5 years, and 67% at 10 years. CONCLUSIONS: Use of a structured protocol for the percutaneous treatment of benign biliary strictures yields durable long-term results, suggesting that percutaneous treatment is an effective therapy.

Effect of central venous angioplasty on hemodialysis access circuit flow: prospective study of 25 symptomatic patients.

PURPOSE: To quantify the effect of central venous percutaneous transluminal angioplasty (PTA) on blood flow within hemodialysis access circuits in patients with symptomatic central venous stenosis (CVS). MATERIALS AND METHODS: This prospective study enrolled 30 adults with symptoms attributable to CVS ipsilateral to their access. Five subjects were deregistered because of a lack of CVS (n = 1), untreatable lesion (n = 1), or improper flow measurement timing (n = 3); 25 completed the study (15 men and 10 women; mean age, 62 y; age range, 33-87 y). There were 7 fistulae, 15 grafts, and 3 hybrid access circuits. Mean access age was 675 days (range, 16-3,039 d). Mean CVS symptom duration was 37 days (range, 3-120 d). Peripheral stenoses, if present, were treated first. Intraaccess flow was measured immediately before and immediately after CVS treatment (PTA, stent). RESULTS: Eleven patients had only CVS, whereas 14 had at least 1 peripheral lesion in addition to CVS. All stenoses underwent PTA. Mean flow rates were 1,424 mL/min (range, 565-2,765 mL/min) before PTA and 1,535 mL/min (range, 598-2,545 mL/min) afterward, yielding a mean increase of 111 mL/min ± 456 or 15% ± 34 (range, -70% to +100%; 95% confidence interval, 1%-29%). Flow was decreased in 9 patients (36%). CVS symptoms were reduced in 24 patients (96%) and recurred in 14 (58%) within a mean of 110 days (range, 7-459 d) after initial PTA. Mean follow-up was 371 days (range, 17-592 d). CONCLUSIONS: CVS symptoms were observed to occur over a wide range of blood flow rates. On average, central venous PTA only mildly increased flow yet reduced symptoms regardless of flow change.

Initial Clinical Experience: Symmetric-Tip Dialysis Catheter with Helical Flow Characteristics Improves Patient Outcomes.

PURPOSE: To report preliminary clinical experience with a new symmetric-tip dialysis catheter compared with a conventional split-tip catheter. MATERIALS AND METHODS: Over a 5-month period, patients requiring a tunneled catheter for hemodialysis or undergoing exchange of a dysfunctional dialysis catheter at a tertiary academic medical center were retrospectively analyzed. Patients underwent placement of a VectorFlow or Ash Split Cath catheter at the discretion of the inserting interventional radiologist. Patient demographics, catheter patency, mean blood flow rate, and arterial and venous pressures were compared according to catheter type. Catheter failure was analyzed based on clinical and anatomic variables by using a multivariate Cox proportional-hazards model. RESULTS: A total of 33 VectorFlow and 46 Ash Split Cath catheters were placed. Patients in the VectorFlow group had significantly higher body mass index (P = .013) and Charlson Comorbidity Index (P = .049), as well as more non-internal jugular vein placements. At 120 days, 89% of VectorFlow catheters remained functional, compared with 45% of Ash Split Cath catheters (P = .046). The VectorFlow catheter was associated with 16% lower arterial pressures during dialysis (P = .009); mean blood flow rate was equivalent. On multivariate analysis, the risk of catheter failure was 13.3 times higher in the Ash Split Cath group compared with the VectorFlow group (P = .004). Left-sided catheters were also predictive of catheter failure (relative risk = 5.5; P = .02). CONCLUSIONS: The VectorFlow catheter was associated with a significant increase in intervention-free catheter patency compared with the Ash Split Cath catheter, with equivalent flow at lower arterial pressures during dialysis.

Catheter-based intraaccess blood flow measurement as a problem-solving tool in hemodialysis access intervention.

PURPOSE: To investigate retrospectively the use of catheter-based intraaccess blood flow measurements as an adjunct to physical examination and fistulography in hemodialysis access interventions. MATERIALS AND METHODS: Among 1,540 dialysis interventions performed at a single institution in a 2.5-year period, 104 qualifying catheter-based flow measurements were made in 70 mature native fistula interventions in 55 patients and 34 graft interventions in 31 patients. The flow rate threshold prompting intervention was generally 600 mL/min, but some variation existed depending on the clinical setting. RESULTS: The most common indication for measurement of blood flow was to determine the hemodynamic significance of a fistula inflow stenosis (n = 25), of which only four had subsequent intervention. Other common indications included decision-making resulting in further angioplasty or stent implantation of noninflow lesions (fistulas, n = 10; grafts, n = 23) versus termination of the procedure (n = 23), problem-solving in cases in which there was no visible lesion to explain the clinical indicator of access failure (n = 17), evaluation for high-flow-related cardiac risk in aneurysmal fistulas (n = 13), suboptimal evaluation of the inflow (n = 8), and suboptimal physical examination (n = 6). Overall, flow measurements supported a decision to perform angioplasty (n = 11) or stent placement (n = 3) in 17% of fistula interventions and 35% of graft interventions. CONCLUSIONS: The major benefit of flow measurement was to support a decision to withhold further angioplasty or stent placement.

Outcomes of percutaneous interventions in transposed hemodialysis fistulas compared with nontransposed fistulas and grafts.

PURPOSE: To compare postpercutaneous intervention outcomes of autogenous venous-transposition arteriovenous fistulas (AVFs) versus those of autogenous nontransposed AVFs (nAVFs) and prosthetic arteriovenous grafts (AVGs). MATERIALS AND METHODS: A total of 591 hemodialysis accesses (195 transposed AVFs [tAVFs], 205 nAVFs, 191 AVGs) in 522 patients (278 male; mean age, 57 y; range, 15­91 y) underwent percutaneous transluminal angioplasty (PTA) and/or mechanical thrombectomy (ie, declotting). Access characteristics, surgical history, percutaneous interventions, postinterventional primary and secondary access patency, and follow-up data were collected. Cox proportional-hazards regression analyses, Fisher exact tests, and χ2 tests were performed. RESULTS: Mean follow-up period was 32 months. Mean access ages at initial percutaneous intervention were 260 days (tAVF), 206 days (nAVF), and 176 days (AVG; P < .01). One-year postinterventional primary patency (PIPP) rates were 25% (tAVF), 24% (nAVF), and 14% (AVG). One-year postinterventional secondary patency (PISP) rates were 77% (tAVF), 61% (nAVF), and 63% (AVG). Median PIPP durations were 138 days (tAVF), 121 days (nAVF), and 79 days (AVG; P = .0001). Median PISP durations were 1,076 days (tAVF), 783 days (nAVF), and 750 days (AVG; P = .019). Total interventions needed to maintain PISP were 2.4 (tAVF), 1.3 (nAVF), and 3.2 (AVG) per patient-year (P < .001), which included 1.9, 1.2, and 1.4 PTAs (P < .01) and 0.45, 0.15, and 1.8 declotting procedures, respectively (P < .001). CONCLUSIONS: Based on the number of percutaneous interventions needed to maintain PISP, these results confirm the current Dialysis Outcomes Quality Initiative access preference of nAVFs before tAVFs before AVGs. tAVFs offered superior postinterventional outcomes than AVGs. With additional interventions, tAVFs could even outperform nAVFs in terms of PISP.

Percutaneous Fluoroscopic-Guided Creation of Neoanastomosis for the Treatment of Biliary Occlusions.

PURPOSE: Complete biliary occlusions at different anatomic locations that are not amenable to surgical, endoscopic, or routine percutaneous methods pose a challenge to physicians. Biliary ductal neoanastomosis technique can play a very important role in solving such clinical problems. MATERIALS: Between October 2004 and January 2018, six patients were treated in our institution for biliary drainage using biliary ductal neoanastomosis technique via sharp recanalization and a staged approach to achieve internal/external biliary drainage. All procedures were performed in an angiography suite by an interventional radiologist after multidisciplinary discussion. RESULTS: The mean patient age of the cohort was 54 years and 50% of the patients were female (three/six patients). The cause of obstruction was complications or disease progression after  Whipple procedure in four patients, partial hepatectomy in one patient and benign biliary stricture after radioembolization in one patient. All patients were treated with percutaneous biliary neoanastomosis. All procedures were successfully performed in all six patients (100% technical success) without any major complications. All patients were successfully managed by capped drainage catheters for the duration of the follow up (one patient was transitioned to endoscopically inserted biliary stent, and in one patient the tube was eventually removed after establishment of patent neoanastomosis). CONCLUSIONS: Biliary ductal neoanastomosis is an effective treatment option when the anatomy has been significantly altered in the post-surgical setting and wire cannot be safely passed into target draining organ or the remainder of biliary system. When performed by an experienced operator, this technique is safe and effective with a high technical success rate.

Impact of a Monthly Compliance Review on Interventional Radiology Adverse Event Reporting.

PURPOSE: Our aims were to analyze the change in interventional radiology physician major adverse event (AE) reporting after initiation of a monthly morbidity and mortality (M&M) conference compliance review and to describe the association of procedure class and potentially preventable errors with major AE occurrence. METHODS: In late 2010, to motivate timely reporting, we instituted a structured monthly M&M conference review confirming whether each complication warranted institutional AE reporting and whether timely reporting had occurred. In this study, we retrospectively analyzed the M&M conference minutes over the subsequent 5 years. Logistic regression was used to model the change of AE reporting over time as well as the association of procedure class with the risk of an AE. Each AE was classified as to whether it seemed potentially preventable. RESULTS: There were 46,660 patient encounters, 1,160 (2.5%) major and minor complications, and 462 (1.0%) reportable AEs. From 2011 to 2015, the percentage of reportable AEs reported increased from 67% to 98%. The number of months from initiation of the M&M conference review was a significant predictor of the likelihood of AE reporting (odds ratio 1.06, 95% confidence interval 1.04, 1.08, P < .0001). Procedure class was strongly associated with the risk of a reportable AE (P < .0001). At least 111 (24%) reportable AEs were potentially preventable. CONCLUSIONS: Increasing AE reporting occurred after initiation of a monthly M&M conference compliance review. The incidence of reportable AEs was strongly associated with procedure class, and a significant percentage of these events were potentially preventable.

The Impact of Bridging LRT on Survival in Patients Listed for Liver Transplantation.

PURPOSE: Locoregional therapy (LRT) is recommended for certain groups of patients with hepatocellular carcinoma (HCC) listed for orthotopic liver transplantation (OLT) with expected wait times greater than 6 months. A retrospective single-center study was performed to evaluate the effect of LRT on the outcomes of patients with HCC listed for OLT. METHODS: Institutional database was reviewed to identify the patients listed for OLT with HCC (March 1998-December 2010). Patient and tumor characteristics were recorded with a follow-up period of 6.5 years from diagnosis. RESULTS: Out of 359 listed patients, 72 patients were delisted (delisted group) and 287 underwent orthotopic liver transplantation (OLT group). One hundred fifty-five and 45 patients from the OLT and delisted groups underwent locoregional therapy (LRT), respectively. Median wait time and sum of largest tumor diameter were significantly higher for patients receiving LRT. LRT was associated with significantly better survival among delisted patients at the end of follow-up (1249.6 ± 137.4 vs. 742.1 ± 155.4 days, p = 0.028). In the OLT group, survival was similar between LRT and no LRT group, but survival was significantly better in patients with largest tumor diameter ≥30 mm (1949.4 ± 95.1 vs. 1694.8 ± 135.5, p = 0.02). CONCLUSION: Patients with HCC and the largest tumor greater than 30 mm treated with LRT prior to OLT have improved survival compared to patients not receiving LRT. Additionally, for patients who did not undergo transplant survival is significantly longer for those receiving LRT.

Metastatic breast carcinoma presenting as a large pulmonary embolus: case report and review of the literature.

Involvement of the pulmonary vasculature by carcinoma of the breast typically occurs in the form of microscopic tumor emboli involving the small arteries, arterioles, or capillaries. Obstruction of a large pulmonary artery by a tumor embolus has not been reported. We describe a patient with a history of breast carcinoma diagnosed 5 years previously who sought treatment for dyspnea and a large mass in the right pulmonary artery suggestive of a pulmonary embolus. After failure of both systemic and intraarterial thrombolytic therapy, a biopsy of the mass was obtained, which revealed adenocarcinoma of the breast. Systemic chemotherapy with doxorubicin and cyclophosphamide was initiated and resulted in the complete resolution of her symptoms.

Diagnostic yield of transjugular liver biopsy samples to evaluate for infectious etiology of liver dysfunction in bone marrow transplant recipients.

PURPOSE: To determine the diagnostic yield of transjugular liver biopsy (TJLBx) samples to evaluate for infectious etiology (immunosuppressed protocol [ISP] of TJLBx) in bone marrow transplant (BMT) recipients. METHODS: A retrospective review of 78 TJLBx in 61 patients who had undergone BMT was undertaken. Biopsy was performed with an automated 19-gauge needle set. The primary indication was suspected graft-versus-host disease in all; a subset also sought to detect infectious liver pathology. In these (n = 31 biopsy samples, 22 patients), an ISP was used with tissue sent for bacterial, viral, fungal, and mycobacterial analysis in addition to histology. In the remainder (n = 47 biopsy samples, 41 patients), tissue was sent for histology only (H). Sample adequacy, histological diagnosis, microorganism assay results (ISP), and complications were reviewed. To assess sample adequacy in BMT compared to non-BMT patients, random control sample of 77 biopsy samples in 75 inpatients during the same period was reviewed (C). RESULTS: All but 1 TJLBx (C group) were technically successful (99%). One major (ISP) and 5 minor complications occurred (H = 3, ISP = 1, C = 1). There were 3 inadequate specimens (6.4%) in the H group, 4 in the ISP group (12.9%), and 4 in the C group (5.2%) (p = NS). No organisms were isolated in any ISP biopsy samples (yield 0%). CONCLUSION: When ISP is requested in BMT recipients, biopsy yields were lower, for unclear reasons possibly relating to degree of liver injury. ISP adds no useful positive information over histology alone. The value of negative cultures in this population is unclear.

Thrombolytic therapy in the setting of arterial line-induced ischemia.

PURPOSE: To evaluate the use of percutaneous transcatheter thrombolysis in the treatment of thrombosis due to radial artery cannulation. METHODS AND RESULTS: Seven patients (4 women; age range 41-62 years) with symptomatic cannulation-induced thrombosis and failure to improve after systemic anticoagulation underwent 8 catheter-directed thrombolytic infusions at our institution over a 3-year period. Access was either antegrade through the brachial artery or retrograde through the femoral artery. Thrombolytic infusions with urokinase began 2 to 12 days (average 6) after removal of the radial artery catheter. The thrombolytic infusion was successful in 5 of 7 patients based on angiographic flow restoration with <20% residual thrombus and significant clinical improvement in the ischemia. CONCLUSIONS: When systemic anticoagulation has failed, percutaneous catheter-directed thrombolytic infusion appears to be effective in the treatment of most patients with severe ischemic hand symptoms due to thrombosis after radial artery cannulation.

Percutaneous removal of a fractured endostent remnant from the portal vein.

We report the case of a liver transplant patient who developed a biliary stricture 3 years postoperatively which was treated with an endostent. During endoscopic removal, the stent fractured and a portion of it lodged itself within the intrahepatic portion of a portal vein branch. The endostent fragment was retrieved percutaneously using interventional radiology techniques. Risk factors for endostent fracture and migration as well as various percutaneous retrieval methods are reviewed in this article.