Long-term renal function outcomes after renal cryoablation complicated by major hemorrhage requiring selective transarterial embolization.

PURPOSE: To determine long-term renal function outcomes after renal cryoablation complicated by major hemorrhage requiring transarterial embolization compared to patients who underwent uncomplicated renal cryoablation without major hemorrhage. METHODS: Utilizing a matched cohort study design, retrospective review identified 23 patients who underwent percutaneous image-guided renal cryoablation complicated by major hemorrhage requiring ipsilateral transarterial embolization (TAE group) and a control group of 23 patients who underwent uncomplicated renal cryoablation matched 1:1 by age, gender and RENAL Nephrometry score at a single institution from 1/1/2005 to 12/31/2019. Primary outcome parameters included change in creatinine (mg/dl) and estimated glomerular filtration rate (ml/min/1.73 m2; eGFR) from baseline and were compared between TAE and control group using a paired t-test. RESULTS: There was a significantly higher proportion of patients on pre-ablation anticoagulation in the TAE v. control group (30% v. 4%; p = 0.047), but all patients were off anticoagulation and with normal coagulation parameters at the time of cryoablation. Otherwise there were no significant differences in clinical, renal tumor, Charlson co-morbidity index, baseline renal function or cryoablation parameters between the TAE and control group. In the post-ablation period, there was trend toward greater increase in creatinine from baseline to worst post-ablation creatinine in the TAE v. the control group (+ 0.5 ± 0.7 mg/dl v. 0.2 ± 0.1 mg/dl; p = 0.056). However, at a mean follow-up of 42.7 ± 35.7 months, there was no significant difference between the TAE and control group in creatinine (p = 0.68), eGFR (p = 0.60) or change from baseline in creatinine (p = 0.28), eGFR (p = 0.80) or CKD stage (p = 0.74). No patient required initiation of hemodialysis. CONCLUSION: Selective transarterial embolization for post-renal cryoablation hemorrhage does not significantly affect long-term renal function compared to cryoablation alone. Pre-ablation anticoagulation despite normal coagulation at time of ablation may be a risk factor for post-ablation hemorrhage, and warrants further evaluation when considering pre-ablation embolization.

Transjugular Renal Biopsy Bleeding Risk and Diagnostic Yield: A Systematic Review.

This study aimed to better define the safety and efficacy of transjugular renal biopsy (TJRB) based on published studies. Seventeen published articles were included (1,321 biopsies). Complications were classified as major if they resulted in blood transfusion or additional invasive procedures. All other bleeding complications were considered minor. Diagnostic tissue was obtained in 1,193 procedures (90.3%). The total incidence of bleeding complications among 15 articles with complete data was 202 of 892 procedures (22.6%): 162 (18.2%) minor and 40 (4.5 %) major. These results show that TJRB is a feasible procedure for obtaining renal tissue for diagnosis and that most complications are self-limiting.

Facial nerve venous malformation: A radiologic and histopathologic review of 11 cases.

OBJECTIVE: The purpose of this article was to provide a combined pathologic and radiologic review of previous pathologically diagnosed facial nerve "hemangiomas" to confirm that these lesions are most characteristic of venous malformations rather than neoplasms. STUDY DESIGN: Retrospective radiologic, clinical, and histopathologic review of all patients with a previous pathologically diagnosed facial nerve hemangioma of the temporal bone who underwent computed tomography or magnetic resonance imaging (MRI) were included. A consensus radiologic review for characteristic features and pathologic analysis was performed. MATERIALS AND METHODS: A panel of 4 neuroradiologists retrospectively analyzed CT and MRI exams for 11 facial nerve hemangiomas and provided a consensus agreement on the characteristic imaging features. Concurrently, two neuropathologists reevaluated archived tissue specimens from these lesions and applied additional immunohistochemical and histochemical stains including D240, CD31, smooth muscle actin (SMA), Verhoeff Van Gieson (VVG) and glucose transporter 1 (GLUT1). RESULTS: Lesions were composed of dilated vascular spaces with a simple, CD31-positive endothelial lining and a smooth muscle component. All lesions were negative for markers found in arterial and lymphatic malformations and infantile hemangiomas. They had characteristic radiologic features previously ascribed to facial nerve hemangiomas. Namely, these lesions are typically T1 isointense or hypointense and T2 hyperintense relative to cerebral cortex and heterogeneously enhance on MRI. Bony canal expansion and erosion, intralesional calcification, and intracranial extension are common. CONCLUSIONS: On the basis of this radiologic and pathologic review, these lesions are best characterized as venous malformations. LEVEL OF EVIDENCE: 4.

Future Liver Remnant Hypertrophy after Portal Vein Embolization Is Inversely Correlated with Intrahepatic Tumor Burden.

PURPOSE: To determine if there is a correlation between intrahepatic tumor volume and future liver remnant (FLR) hypertrophy after portal vein embolization (PVE). MATERIALS AND METHODS: Forty-four consecutive patients with hepatocellular carcinoma or metastatic colorectal cancer who underwent PVE from 2009 to 2017 and who had complete imaging follow-up were retrospectively reviewed. To maximize the accuracy of tumor volume measurements, 11 patients were excluded for having more than 5 intrahepatic tumors. Volumetric analyses of the patient livers before and after PVE, as well as pre-embolization intrahepatic tumor burden, were performed. RESULTS: A significant inverse correlation was observed between tumor volume and FLR hypertrophy after PVE (Spearman ρ = -0.53, P = .002). Initial FLR volume was also inversely correlated with subsequent hypertrophy (P = .01). Fourteen patients received neoadjuvant chemotherapy 1 month prior to intervention. The number of chemotherapy cycles did not affect hypertrophy (P = .57). Patients with cirrhosis experienced less FLR hypertrophy than patients without cirrhosis (P = .02). CONCLUSIONS: Patients with large intrahepatic tumor burden may experience limited FLR hypertrophy.

Percutaneous extrahepatic splenomeso-caval shunt creation in a patient with portal vein thrombosis after Whipple procedure.

A 72-year-old male presented with refractory ascites secondary to portal vein occlusion with cavernomatous transformation following pancreaticoduodenectomy (Whipple procedure). Due to the unfavorable anatomy, transjugular intrahepatic portosystemic shunt was not an option. However, given patency of the spleno-mesenteric confluence and absence of the pancreatic head after the Whipple procedure, a splenomeso-caval shunt was successfully created using a transjugular-transsplenic rendezvous technique.

Can MRI contribute to pulmonary nodule analysis?

BACKGROUND: There is no accurate method distinguishing different types of pulmonary nodules. PURPOSE: To investigate whether multiparametric 3T MRI biomarkers can distinguish malignant from benign pulmonary nodules, differentiate different types of neoplasms, and compare MRI-derived measurements with values from commonly used noninvasive imaging modalities. STUDY TYPE: Prospective. SUBJECTS: Sixty-eight adults with pulmonary nodules undergoing resection. SEQUENCES: Respiratory triggered diffusion-weighted imaging (DWI), periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) fat saturated T2 -weighted imaging, T1 -weighted 3D volumetric interpolated breath-hold examination (VIBE) using CAIPIRINHA (controlled aliasing in parallel imaging results in a higher acceleration). ASSESSMENT/STATISTICS: Apparent diffusion coefficient (ADC), T1 , T2 , T1 and T2 normalized to muscle (T1 /M and T2 /M), and dynamic contrast enhancement (DCE) values were compared with histology to determine whether they could distinguish malignant from benign nodules and discern primary from secondary malignancies using logistic regression. Predictability of primary neoplasm types was assessed using two-sample t-tests. MRI values were compared with positron emission tomography / computed tomography (PET/CT) to examine if they correlated with standardized uptake value (SUV) or CT Hounsfield unit (HU). Intra- and interreader agreements were assessed using intraclass correlations. RESULTS: Forty-nine of 74 nodules were malignant. There was a significant association between ADC and malignancy (odds ratio 4.47, P < 0.05). ADC ≥1.3 µm2 /ms predicted malignancy. ADC, T1 , and T2 together predicted malignancy (P = 0.003). No MRI parameter distinguished primary from metastatic neoplasms. T2 predicted PET positivity (P = 0.016). T2 and T1 /M correlated with SUV (P < 0.05). Of 18 PET-negative malignant nodules, 12 (67%) had an ADC ≥1.3 µm2 /ms. With the exception of T2 , all noncontrast MRI parameters distinguished adenocarcinomas from carcinoid tumors (P < 0.05). T1 , T2 , T1 /M, and T2 /M correlated with HU and therefore can predict nodule density. Combined with ADC, washout enhancement, arrival time (AT), peak enhancement intensity (PEI), Ktrans , Kep , Ve collectively were predictive of malignancy (P = 0.012). Combined washin, washout, time to peak (TTP), AT, and PEI values predicted malignancy (P = 0.043). There was good observer agreement for most noncontrast MRI biomarkers. DATA CONCLUSION: MRI can contribute to pulmonary nodule analysis. Multiparametric MRI might be better than individual MRI biomarkers in pulmonary nodule risk stratification. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.

Prospective Pilot Evaluation of Radiologists and Computer-aided Pulmonary Nodule Detection on Ultra-low-Dose CT With Tin Filtration.

PURPOSE: The aim of this study was to evaluate the ability of computer-aided detection (CAD) and human readers to detect pulmonary nodules ≥5 mm using 100 kV ultra-low-dose computed tomography (ULDCT) utilizing a tin filter. MATERIALS AND METHODS: After informed consent, 55 patients prospectively underwent standard-dose chest CT (SDCT) using 120 kV followed by ULDCT using 100 kV/tin. Reference nodules ≥5 mm were identified by a thoracic radiologist using SDCT. Four thoracic radiologists marked detected nodules on SDCT and ULDCT examinations using a dedicated computer workstation. After a 6-month memory extinction, readers were shown the same ULDCT cases with all CAD markings as well as their original detections, and characterized CAD detections as true positive or false positive. RESULTS: Volume CT Dose index (CTDIvol) for SDCT and ULDCT were 5.3±2 and 0.4±0.2 mGy (P<0.0001), respectively. Forty-five reference nodules were detected in 30 patients. Reader sensitivity varied widely but similarly for SDCT (ranging from 45% to 87%) and ULDCT (45% to 83%). CAD sensitivity was 76% (34/45) for SDCT and 71% (32/45) for ULDCT. After CAD, reader sensitivity substantially improved by 19% and 18% for 2 readers, and remained nearly unchanged for the other 2 readers (0% and 2%), despite reader perception that many more nodules were identified with CAD. There was a mean of 2 false-positive CAD detections/case. CONCLUSIONS: ULDCT with 100 kV/tin reduced patient dose by over 90% without compromising pulmonary nodule detection sensitivity. CAD can substantially improve nodule detection sensitivity at ULDCT for some readers, maintaining interobserver performance.

Thermal ablation of intrahepatic cholangiocarcinoma: Safety, efficacy, and factors affecting local tumor progression.

PURPOSE: To evaluate the safety and oncologic efficacy of percutaneous thermal ablation of intrahepatic cholangiocarcinoma (ICC) and identify risk factors for local tumor progression (LTP). MATERIALS AND METHODS: Retrospective review of an institutional tumor ablation registry demonstrated that 20 patients (9 males, 11 females; mean age 62.5 ± 15.8 years) with 50 ICCs (mean size 1.8 ± 1.3 cm) were treated with percutaneous radiofrequency ablation (RFA) or microwave ablation (MWA) between 2006 and 2015. Thirty-eight of the treated ICCs (76%) were metastases that developed after surgical resection of the primary tumor. Patient demographics, procedure technical parameters, and clinical outcomes were reviewed. A Cox proportional hazards model was used to examine the risk of LTP by ablation modality. Survival analyses were performed using the Kaplan-Meier method. RESULTS: Mean imaging follow-up time was 41.5 ± 42.7 months. Forty-four (88%) ICCs were treated with RFA, and 6 (12%) with MWA. Eleven (22%) cases of LTP developed in 5 (25%) patients. The median time to LTP among these 11 tumors was 7.1 months (range, 2.3-22.9 months). Risk of LTP was not significantly different for ICCs treated with MWA compared to RFA (HR 2.72; 95% CI 0.58-12.84; p = 03.21). Median disease-free survival was 8.2 months (1.1-70.4 months), and median overall survival was 23.6 months (7.4-122.5 months). No major complication occurred. CONCLUSIONS: Percutaneous thermal ablation is a safe and effective treatment for patients with ICCs and may be particularly valuable in unresectable patients, or those who have already undergone hepatic surgery. Tumor size and ablation modality were not associated with LTP, whereas primary tumors and superficially located tumors were more likely to subsequently recur.

A virtual clinical trial using projection-based nodule insertion to determine radiologist reader performance in lung cancer screening CT.

Task-based image quality assessment using model observers is promising to provide an efficient, quantitative, and objective approach to CT dose optimization. Before this approach can be reliably used in practice, its correlation with radiologist performance for the same clinical task needs to be established. Determining human observer performance for a well-defined clinical task, however, has always been a challenge due to the tremendous amount of efforts needed to collect a large number of positive cases. To overcome this challenge, we developed an accurate projection-based insertion technique. In this study, we present a virtual clinical trial using this tool and a low-dose simulation tool to determine radiologist performance on lung-nodule detection as a function of radiation dose, nodule type, nodule size, and reconstruction methods. The lesion insertion and low-dose simulation tools together were demonstrated to provide flexibility to generate realistically-appearing clinical cases under well-defined conditions. The reader performance data obtained in this virtual clinical trial can be used as the basis to develop model observers for lung nodule detection, as well as for dose and protocol optimization in lung cancer screening CT.

Treatment of In-Stent Restenosis in Patients with Renal Artery Stenosis.

PURPOSE: To determine clinical outcomes of patients treated for renal artery in-stent restenosis (ISR) with atherosclerotic renal artery stenosis. MATERIALS AND METHODS: A retrospective review was performed of the clinical data of all patients who underwent renal artery stent placement for atherosclerotic renal artery stenosis from 1996 to 2009. Medical records of patients were reviewed for relevant clinical history, including blood pressure, antihypertensive medications, and renal function data before and after an intervention. In 1,052 patients, 1,090 renal artery stent placements were performed. Of these, 101 stents in 79 patients developed ISR, which was treated with either percutaneous transluminal angioplasty (PTA) or repeat stent placement. Procedural details, including modality of intervention, stent diameter, and time to restenosis, were recorded. Hypertensive agent and use of statins were recorded. Univariate analysis was performed to identify risk factors associated with restenosis after treatment of ISR. RESULTS: Patients treated with repeat stent placement were 6.89 times more likely to lose patency after treatment than patients treated with PTA (P < .01). No additional clinical or procedural factor, including smoking history; presence of cardiac, renal, or metabolic disease; use of statin at time of ISR treatment; or diameter of treatment (stent or PTA), had a significant association with duration of stent or angioplasty patency. CONCLUSIONS: Treatment of renal artery ISR with PTA among patients with atherosclerotic renal artery stenosis has a lower rate of subsequent ISR compared with repeat stent placement.

A Practice Quality Improvement Project: Reducing Dose of Routine Chest CT Imaging in a Busy Clinical Practice.

The purpose of this report is to describe our experience with the implementation of a practice quality improvement (PQI) project in thoracic imaging as part of the American Board of Radiology Maintenance of Certification process. The goal of this PQI project was to reduce the effective radiation dose of routine chest CT imaging in a busy clinical practice by employing the iDose(4) (Philips Healthcare) iterative reconstruction technique. The dose reduction strategy was implemented in a stepwise process on a single 64-slice CT scanner with a volume of 1141 chest CT scans during the year. In the first annual quarter, a baseline effective dose was established using the standard filtered back projection (FBP) algorithm protocol and standard parameters such as kVp and mAs. The iDose(4) technique was then applied in the second and third annual quarters while keeping all other parameters unchanged. In the fourth quarter, a reduction in kVp was also implemented. Throughout the process, the images were continually evaluated to assure that the image quality was comparable to the standard protocol from multiple other scanners. Utilizing a stepwise approach, the effective radiation dose was reduced by 23.62 and 43.63 % in quarters two and four, respectively, compared to our initial standard protocol with no perceived difference in diagnostic quality. This practice quality improvement project demonstrated a significant reduction in the effective radiation dose of thoracic CT scans in a busy clinical practice.

Brain-type natriuretic peptide and right ventricular end-diastolic volume index measurements are imprecise estimates of circulating blood volume in critically ill subjects.

BACKGROUND: Surrogate indicators have often been used to estimate intravascular volume to guide fluid management. Brain-type natriuretic peptide (BNP) has been used as a noninvasive adjunct in the diagnosis of fluid overload and as a marker of response to therapy, especially in individuals with congestive heart failure. Similarly, right ventricular end-diastolic volume index (RVEDVI) measurements represent another parameter used to guide fluid resuscitation. The aim of this study was to evaluate whether BNP and RVEDVI are clinically valuable parameters that can distinguish among hypovolemia, euvolemia, and hypervolemia, as measured by blood volume (BV) analysis in critically ill surgical subjects. METHODS: This observational study was part of a prospective, randomized controlled trial. Subjects with pulmonary artery catheters for the treatment of traumatic injuries, severe sepsis/septic shock, cardiovascular collapse, adult respiratory distress syndrome, and postsurgical care were studied. Circulating BV was measured by a radioisotope dilution technique using the BVA-100 Analyzer (Daxor Corporation, New York, NY) within the first 24 hours of acute resuscitation. BV results were reported as percent deviation from the patient's ideal BV based on height and percent deviation from optimum weight. Hypovolemia was defined as less than 0%, euvolemia was defined as 0% to +16%, and hypervolemia was defined as greater than +16% deviation from ideal BV. RVEDVI was measured by continuous cardiac output pulmonary artery catheters (Edwards Lifesciences, Irvine, CA). BNP and RVEDVI measurements obtained with BV analysis were evaluated with Fisher's exact test and regression analysis. RESULTS: In 81 subjects, there was no difference in BV status between those with BNP of 500 pg/mL or greater and BNP of less than 500 pg/mL (p = 0.82) or in those with RVEDVI of 140 mL/m or greater and RVEDVI of less than 140 mL/m (p = 0.43). No linear relationship existed between BV and these parameters. CONCLUSION: In critically ill surgical patients, BNP and RVEDVI were not associated with intravascular volume status, although they may be useful as indices that reflect increased cardiac preload. LEVEL OF EVIDENCE: Diagnostic study, level III.

Four-year cumulative radiation exposure in patients undergoing computed tomography angiography for suspected pulmonary embolism.

Purpose. The objective of this study was to determine the estimated effective radiation dose of pulmonary CT angiography (CTA) for suspected pulmonary embolism (PE) contributing to total medical radiation exposure over a 4-year period. Materials and Methods. This investigation retrospectively reviewed 300 patients who presented to the emergency department and received a pulmonary CTA scan for suspected PE. We evaluated these patients' electronic medical record to determine their estimated radiation exposure to CT scans during the following four years. Using DLP to E conversion coefficients, we calculated the cumulative effective radiation dose each subject received. Results. A total of 900 CT scans were reviewed in this study. Pulmonary CTA delivered an average effective radiation dose of 10.7 ± 2.5 mSv and accounted for approximately 65% of subjects' 4-year cumulative medical radiation dose. Only 6.3% of subjects had a positive acute PE according to their radiology report. Conclusion. Pulmonary CTA accounted for the majority of subjects' medically related effective radiation dose over a 4-year period. With only a minority of subjects having positive findings for acute PE, increased efforts should be made to clinically assess pretest probability before the consideration of imaging.