Management of Pancreatico-duodenal arterio-venous malformation.

PURPOSE: To describe the interventional management and clinical outcome of pancreatico-duodenal arterio-venous malformations (PDAVMs). MATERIAL AND METHODS: Seven patients presenting a PDAVM (6 women, 1 male; mean age: 61) were retrospectively reviewed. Technical, clinical success and complications of embolization and surgical management of symptomatic PDAVMs were assessed. Technical success was defined as a complete occlusion of the PDAVM and clinical success as no clinical symptom or recurrence during follow-up. Patients with asymptomatic PDAVMs were followed clinically, by Doppler ultrasound and CT-angiography. RESULTS: Mean follow-up time was 69 months (15-180). Five symptomatic patients presented with upper gastrointestinal bleeding (n=3), ascites (n=1), and abdominal pain (n=1). Two patients were asymptomatic. The PDAVMs were classified as follow: Yakes I (1), IIIa (2), IIIb (3) and IV (1). Five symptomatic patients were treated with 9 embolization sessions with arterial approach (onyx®, glue, coils) in 7 and venous approach in 2 (plugs, coils, covered stents, STS foam and onyx®). Technical success of embolization was 60% (3/5). Devascularization was incomplete for 2 Yakes IIIB patients. Clinical success of embolization was estimated at 80% (4/5) as one patient required additional surgery (Whipple) because of persistent bleeding. One splenic vein thrombosis was treated successfully by mechanical thrombectomy and heparin. No recurrence occurred during follow-up. No progression was documented in asymptomatic patients. CONCLUSION: Embolization of symptomatic PDAVMs is effective and surgery should be performed in second intention. Complete devascularization is more difficult to obtain in Yakes III PDAVM.

Assessment of hepatocellular carcinoma treatment response with LI-RADS: a pictorial review.

Computed tomography (CT) and magnetic resonance imaging (MRI) play critical roles for assessing treatment response of hepatocellular carcinoma (HCC) after locoregional therapy. Interpretation is challenging because posttreatment imaging findings depend on the type of treatment, magnitude of treatment response, time interval after treatment, and other factors. To help radiologists interpret and report treatment response in a clear, simple, and standardized manner, the Liver Imaging Reporting and Data System (LI-RADS) has developed a Treatment Response (LR-TR) algorithm. Introduced in 2017, the system provides criteria to categorize response of HCC to locoregional treatment (e.g., chemical ablation, energy-based ablation, transcatheter therapy, and radiation therapy). LR-TR categories include Nonevaluable, Nonviable, Equivocal, and Viable. LR-TR does not apply to patients on systemic therapies. This article reviews the LR-TR algorithm; discusses locoregional therapies for HCC, treatment concepts, and expected posttreatment findings; and illustrates LI-RADS treatment response assessment with CT and MRI.

Dynamic contrast-enhanced MRI to assess hepatocellular carcinoma response to Transarterial chemoembolization using LI-RADS criteria: A pilot study.

PURPOSE: To identify quantitative dynamic contrast-enhanced (DCE)-MRI perfusion parameters indicating tumor response of hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE). MATERIALS AND METHODS: This prospective pilot study was approved by our institutional review board; written and informed consent was obtained for each participant. Patients underwent DCE-MRI examinations before and after TACE. A variable flip-angle unenhanced 3D mDixon sequence was performed for T1 mapping. A dynamic 4D mDixon sequence was performed after contrast injection for assessing dynamic signal enhancement. Nonparametric analysis was conducted on the time-intensity curves. Parametric analysis was performed on the time-concentration curves using a dual-input single-compartment model. Treatment response according to Liver Reporting and Data System (LI-RADS) v2018 was used as the reference standard. The comparisons within groups (before vs. after treatment) and between groups (nonviable vs. equivocal or viable tumor) were performed using nonparametric bootstrap taking into account the clustering effect of lesions in patients. RESULTS: Twenty-eight patients with 52 HCCs (size: 10-104 mm) were evaluated. For nonviable tumors (n = 27), time to peak increased from 62.5 ±â€¯18.2 s before to 83.3 ±â€¯12.8 s after treatment (P< 0.01). For equivocal or viable tumors (n = 25), time to peak and mean transit time significantly increased (from 54.4 ±â€¯24.1 s to 69.5 ±â€¯18.9 s, P < 0.01 and from 14.2 ±â€¯11.8 s to 33.9 ±â€¯36.8 s, P= 0.01, respectively) and the transfer constant from the extracellular and extravascular space to the central vein significantly decreased from 14.8 ±â€¯14.1 to 8.1 ±â€¯9.1 s-1 after treatment (P= 0.01). CONCLUSION: This prospective pilot DCE-MRI study showed that time to peak significantly changed after TACE treatment for both groups (nonviable tumors and equivocal or viable tumors). In our cohort, several perfusion parameters may provide an objective marker for differentiation of treatment response after TACE in HCC patients.

LI-RADS for CT diagnosis of hepatocellular carcinoma: performance of major and ancillary features.

PURPOSE: To evaluate the diagnostic performance of Liver Imaging Reporting and Data System (LI-RADS) v2017 major features, the impact of ancillary features, and categories on contrast-enhanced computed tomography (CECT) for the diagnosis of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: This retrospective study included 59 patients (104 observations including 72 HCCs) with clinical suspicion of HCC undergoing CECT between 2013 and 2016. Two radiologists independently assessed major and ancillary imaging features for each liver observation and assigned a LI-RADS category based on major features only and in combination with ancillary features. The composite reference standard included pathology or imaging. Per-lesion estimates of diagnostic performance of major features, ancillary features, and LI-RADS categories were assessed by generalized estimating equation models. RESULTS: Major features (arterial phase hyperenhancement, washout, capsule, and threshold growth) respectively had a sensitivity of 86.1%, 81.6%, 20.7%, and 26.1% and specificity of 39.3%, 67.9%, 89.9%, and 85.0% for HCC. Ancillary features (ultrasound visibility as discrete nodule, subthreshold growth, and fat in mass more than adjacent liver) respectively had a sensitivity of 42.6%, 50.8%, and 15.1% and a specificity of 79.2%, 66.9%, and 96.4% for HCC. Ancillary features modified the final category in 4 of 104 observations. For HCC diagnosis, categories LR-3, LR-4, LR-5, and LR-TIV (tumor in vein) had a sensitivity of 5.3%, 29.0%, 53.7%, and 10.7%; and a specificity of 49.1%, 84.4%, 97.3%, and 96.4%, respectively. CONCLUSION: On CT, LR-5 category has near-perfect specificity for the diagnosis of HCC and ancillary features modifies the final category in few observations.

Selective embolization with magnetized microbeads using magnetic resonance navigation in a controlled-flow liver model.

PURPOSE: The purpose of this study was to demonstrate the feasibility of using a custom gradient sequence on an unmodified 3T magnetic resonance imaging (MRI) scanner to perform magnetic resonance navigation (MRN) by investigating the blood flow control method in vivo, reproducing the obtained rheology in a phantom mimicking porcine hepatic arterial anatomy, injecting magnetized microbead aggregates through an implantable catheter, and steering the aggregates across arterial bifurcations for selective tumor embolization. MATERIALS AND METHODS: In the first phase, arterial hepatic velocity was measured using cine phase-contrast imaging in seven pigs under free-flow conditions and controlled-flow conditions, whereby a balloon catheter is used to occlude arterial flow and saline is injected at different rates. Three of the seven pigs previously underwent selective lobe embolization to simulate a chemoembolization procedure. In the second phase, the measured in vivo controlled-flow velocities were approximately reproduced in a Y-shaped vascular bifurcation phantom by injecting saline at an average rate of 0.6 mL/s with a pulsatile component. Aggregates of 200-µm magnetized particles were steered toward the right or left hepatic branch using a 20-mT/m MRN gradient. The phantom was oriented at 0°, 45°, and 90° with respect to the B0 magnetic field. The steering differences between left-right gradient and baseline were calculated using Fisher's exact test. A theoretical model of the trajectory of the aggregate within the main phantom branch taking into account gravity, magnetic force, and hydrodynamic drag was also designed, solved, and validated against the experimental results to characterize the physical limitations of the method. RESULTS: At an injection rate of 0.5 mL/s, the average flow velocity decreased from 20 ± 15 to 8.4 ± 5.0 cm/s after occlusion in nonembolized pigs and from 13.6 ± 2.0 to 5.4 ± 3.0 cm/s in previously embolized pigs. The pulsatility index measured to be 1.7 ± 1.8 and 1.1 ± 0.1 for nonembolized and embolized pigs, respectively, decreased to 0.6 ± 0.4 and 0.7 ± 0.3 after occlusion. For MRN performed at each orientation, the left-right distribution of aggregates was 55%, 25%, and 75% on baseline and 100%, 100%, and 100% (P < 0.001, P = 0.003, P = 0.003) after the application of MRN, respectively. According to the theoretical model, the aggregate reaches a stable transverse position located toward the direction of the gradient at a distance equal to 5.8% of the radius away from the centerline within 0.11 s, at which point the aggregate will have transited through a longitudinal distance of 1.0 mm from its release position. CONCLUSION: In this study, we showed that the use of a balloon catheter reduces arterial hepatic flow magnitude and variation with the aim to reduce steering failures caused by fast blood flow rates and low magnetic steering forces. A mathematical model confirmed that the reduced flow rate is low enough to maximize steering ratio. After reproducing the flow rate in a vascular bifurcation phantom, we demonstrated the feasibility of MRN after injection of microparticle aggregates through a dedicated injector. This work is an important step leading to MRN-based selective embolization techniques in humans.

LI-RADS for MR Imaging Diagnosis of Hepatocellular Carcinoma: Performance of Major and Ancillary Features.

Purpose To evaluate the performance of major features, ancillary features, and categories of Liver Imaging Reporting and Data System (LI-RADS) version 2014 at magnetic resonance (MR) imaging for the diagnosis of hepatocellular carcinoma (HCC). Materials and Methods This retrospective institutional review board-approved study included patients with liver MR imaging and at least one pathologically proved lesion. Between 2004 and 2016, 102 patients (275 observations including 113 HCCs) met inclusion criteria. Two radiologists independently assessed major and ancillary imaging features for each liver observation and assigned a LI-RADS category. Per-lesion estimates of diagnostic performance of major features, ancillary features, and LI-RADS categories were assessed by using generalized estimating equation models. Results Major features (arterial phase hyperenhancement, washout, capsule, and threshold growth) had a sensitivity of 88.5%, 60.6%, 32.9%, and 41.6%, and a specificity of 18.6%, 84.8%, 98.8%, and 83.2% for HCC, respectively. Ancillary features (mild-moderate T2 hyperintensity, restricted diffusion, mosaic architecture, intralesional fat, lesional fat sparing, blood products, and subthreshold growth) had a sensitivity of 62.2%, 54.8%, 9.9%, 30.9%, 23.1%, 2.8%, and 48.3%, and a specificity of 79.4%, 90.6%, 99.4%, 94.2%, 83.1%, 99.3%, and 91.4% for HCC, respectively. The LR-5 or LR-5 V categories had a per-lesion sensitivity of 50.8% and a specificity of 95.8% for HCC, respectively. The LR-4, LR-5, or LR-5 V categories (determined by using major features only vs combination of major and ancillary features) had a per-lesion sensitivity of 75.9% and 87.9% and a per-lesion specificity of 87.5% and 86.2%, respectively. Conclusion The use of ancillary features in combination with major features increases the sensitivity while preserving a high specificity for the diagnosis of HCC.

Results of a randomized clinical trial of external beam radiation to prevent restenosis after superficial femoral artery stenting.

OBJECTIVE: The objective of this study was to evaluate the safety and efficacy of external beam radiation (EBR) in preventing restenosis after superficial femoral artery (SFA) stenting in comparison with a control group treated with SFA stenting only. METHODS: In this Institutional Review Board-approved study, patients who provided written informed consent were randomly assigned to 0 Gy or 14 Gy of EBR to the stent site 24 hours after SFA stenting. The primary end point was the angiographic binary restenosis rate 2 years after stenting. Categorical and continuous end points were respectively analyzed using logistic regression models and Wilcoxon tests. End points expressed as time to event were analyzed using a log-rank test. RESULTS: The study included 155 patients, 46 women and 109 men (mean age, 66 years; range, 45-85 years). In the 0 and 14 Gy groups, binary restenosis was present, respectively, in 44% (34/77) and 68% (52/76; P = .003) 2 years after stenting. Stent thrombosis occurred in 13% (10/78) of the 0 Gy group and in 33% (25/77) of the 14 Gy group (P = .003). Target lesion revascularization at 2 years was 26% (25/78) in the 0 Gy group and 30% (23/77) in the 14 Gy group (P = .56). There were no significant differences in total walking distances change from baseline to 2 years (46 ± 100 and 26 ± 79 m, respectively, in the 0 Gy and 14 Gy group; P = .25). There were no procedure-related deaths and no major amputations. CONCLUSIONS: A single 14 Gy dose of EBR to the SFA stenting site did not prevent in-stent restenosis.

Role of the transjugular intrahepatic portosystemic shunt in the management of severe complications of portal hypertension in idiopathic noncirrhotic portal hypertension.

UNLABELLED: Idiopathic noncirrhotic portal hypertension is a heterogeneous group of diseases characterized by portal hypertension in the absence of cirrhosis. The efficacy and safety of transjugular intrahepatic portosystemic shunt (TIPS) in this population are unknown. The charts of patients with idiopathic noncirrhotic portal hypertension undergoing TIPS in seven centers between 2000 and 2014 were retrospectively reviewed. Forty-one patients were included. Indications for TIPS were recurrent variceal bleeding (n = 25) and refractory ascites (n = 16). Patients were categorized according to the presence (n = 27) or absence (n = 14) of significant extrahepatic comorbidities. Associated conditions were hematologic, prothrombotic, neoplastic, immune, and exposure to toxins. During follow-up (mean 27 ± 29 months), variceal rebleeding occurred in 7/25 (28%), including three with early thrombosis of the stent. Post-TIPS overt hepatic encephalopathy was present in 14 patients (34%). Eleven patients died, five due the liver disease or complications of the procedure and six because of the associated comorbidities. The procedure was complicated by hemoperitoneum in four patients (10%), which was fatal in one case. Serum creatinine (P = 0.005), ascites as indication for TIPS (P = 0.04), and the presence of significant comorbidities (P = 0.01) at the time of the procedure were associated with death. Mortality was higher in patients with significant comorbidities and creatinine ≥100 µmol/L (P < 0.001). CONCLUSION: In patients with idiopathic noncirrhotic portal hypertension who have normal kidney function or do not have severe extrahepatic conditions, TIPS is an excellent option to treat severe complications of portal hypertension. (Hepatology 2016;64:224-231).

Hepatic hemodynamics in 24 patients with nodular regenerative hyperplasia and symptomatic portal hypertension.

BACKGROUND AND AIM: To evaluate hepatic hemodynamics in patients with nodular regenerative hyperplasia of the liver (NRH) with portal hypertension (PHT). METHODS: We retrospectively reviewed the charts of 24 patients referred for PHT related to biopsy-proven NRH. Hemodynamic measurements included wedged hepatic vein (WHVP) and inferior vena cava (IVCP), and, in 12 patients, portal vein pressure (PVP). Hepatic vein pressure gradient (HVPG: WHVP-IVCP) and portal vein pressure gradient (PVPG: PVP-IVCP) were calculated. RESULTS: Nodular regenerative hyperplasia was associated in 24 patients with various diseases (oxaliplatin chemotherapy, treatment with purine antagonists, post liver transplantation, hematologic and rheumatologic conditions and HIV infection). Liver function parameters were either completely normal or slightly impaired. Patients were referred for gastroesophageal varices (n = 18), and/or ascites (n = 11), and/or splenomegaly (n = 20). In patients with varices or ascites, HVPG was lower than 10 mmHg (a cut-off point for the presence of varices and/or ascites) in 15/21, suggesting a pre-sinusoidal component to their PHT confirmed by a PVP higher than 12 mmHg in 12/12 patients. The mean difference between HVPG and PVPG was 8.7 mmHg in these patients. Ten patients were treated by transjugular intrahepatic portosystemic shunt. None of them re-bled, and one presented transient hepatic encephalopathy. CONCLUSIONS: Presinusoidal PHT associated with NRH is probably related to compression of portal venules by the regenerative nodules. In patients with HTP and a HVPG < 10 mmHg, the diagnosis of NRH must be suspected and PVP measured, which is important in the management of these patients.

Transcatheter arterial chemoembolization of hepatocellular carcinoma as a bridge to liver transplantation: a retrospective study.

Background. Transcatheter arterial lipiodol chemoembolization (TACE) can be used in cirrhotic patients with hepatocellular carcinoma to avoid tumor progression before transplantation. Objective. To evaluate the efficacy and safety of TACE used as a bridge to liver transplantation. Methods. TACE was performed in 30 cirrhotic patients with hepatocellular carcinoma. Milan criteria were used to select patients for transplant. Patients had a good or moderately impaired liver function, no arterioportal fistulae, and a good portal perfusion. Results. 48 TACE were performed in 30 patients. Before transplantation, 4 patients were dropped off the list due to tumor extension or liver failure. Complete necrosis of the tumor was observed in 11 patients and partial necrosis in 15 patients. After transplantation, 6 patients died and tumor recurrence was observed in 5 patients with a tumor beyond Milan criteria or no response to TACE. Conclusion. TACE is useful as a bridge to liver transplantation in a selected group of cirrhotic patients with hepatocellular carcinoma. A combined therapeutic approach before surgery might improve the prognosis in these patients.

Transjugular intrahepatic portosystemic shunt before abdominal surgery in cirrhotic patients: a retrospective, comparative study.

Surgery in cirrhotic patients is associated with high morbidity and mortality related to portal hypertension and liver insufficiency. Therefore, preoperative portal decompression is a logical approach to facilitate abdominal surgery and hopefully to improve postoperative survival. The present study evaluated the clinical outcomes of 18 patients (mean age 58 years) with cirrhosis (seven alcoholics and 11 nonalcoholics) who underwent transjugular intrahepatic portosystemic shunt (TIPS) placement before antrectomy (n=5), colectomy (n=10), small-bowel resection (n=1), pancreatectomy (n=1) and nephrectomy (n=1). TIPS was performed a mean (+/-SD) of 72+/-21 days before surgery and induced a marked mean decrease in portohepatic gradient from 21.4+/-3.9 mmHg to 8.4+/-3.4 mmHg. Cirrhotic patients (n=17) who underwent elective abdominal surgery without preoperative TIPS placement were used as the control group. Both groups were matched for age, etiology of cirrhosis, indications for surgery, type of surgery and coagulation parameters. The mean Pugh score was significantly higher in the TIPS group (7.7 versus 6.2). No significant differences were observed for operative blood loss, postoperative complications, duration of hospitalization and one-month (83% versus 88%) or one-year (54% versus 63%) cumulative survival rate. Analysis using the Cox proportional hazards model showed that neither TIPS placement nor preoperative Pugh score were independent predictors for survival. The present study suggests that preoperative TIPS placement does not improve postoperative evolution after abdominal surgery in cirrhotic patients with good or moderately impaired liver function.

Stent-graft placement for the treatment of thoracic aortic diseases.

The recent development of aortic stent-grafts has brought the management of thoracic aortic diseases into the realm of interventional radiology. Stent-graft placement is now an alternative to surgery for the treatment of descending thoracic aortic aneurysms, ulcers, and fistulas and is sometimes indicated in cases of mycotic aneurysm, posttraumatic aortic rupture, or thoracic descending aortic dissection. Pretreatment imaging is crucial for evaluating patient eligibility, selecting the appropriate stent-graft, and planning the intervention. Stent-graft treatment of long atherosclerotic aneurysms, lesions close to aortic branch vessels, and aortic dissections is subject to technical pitfalls, and adverse events such as endoleaks, stent migration or misplacement, aortic perforation, and vascular trauma will require specific interventions, although they occur in only a minority of patients. Thoracic stent-graft placement in good surgical candidates remains controversial because long-term results are unknown. However, short-term morbidity and mortality rates from endovascular treatment compare favorably with those from surgery, and stent-graft placement is proving to be a safe, minimally invasive, and effective treatment for thoracic aortic diseases and is already the best option in many affected patients who are poor surgical candidates.

Balloon dilation and stent placement for esophageal lesions: indications, methods, and results.

Esophageal balloon dilation and expandable stent placement are safe, minimally invasive, effective treatments for esophageal strictures and fistulas. These procedures have brought the management of dysphagia due to esophageal strictures into the field of interventional radiology. Esophageal dilation is usually indicated for benign stenoses and is technically successful in more than 90% of cases. Most patients with esophageal carcinoma are not candidates for resection; thus, the main focus of treatment is palliation of malignant dysphagia and esophagorespiratory fistulas. Esophageal stent placement, which is approved only for malignant strictures, is one of the main therapeutic options in affected patients and relieves dysphagia in approximately 90% of cases. Dedicated commercially available devices continue to evolve, each with its own advantages and limitations. Stent placement is subject to technical pitfalls, and adverse events occur following esophageal procedures in a minority of cases. Although chest pain is common and self-limited, reflux esophagitis, stent migration, tracheal compression, and esophageal perforation and obstruction require specific interventions. In many cases, these complications can be recognized and treated by the interventional radiologist with minimally invasive techniques.

Helical CT with CT angiography in assessing periampullary neoplasms: identification of vascular invasion.

PURPOSE: To determine the accuracy of helical computed tomography (CT) with CT angiography in identifying vascular invasion by periampullary neoplasms and to assess the added value of CT angiography. MATERIALS AND METHODS: Sixty-nine patients suspected of having periampullary neoplasms were examined. Images from dual phase helical CT with CT angiography were compared with surgical findings in 36 patients. Arterial and venous invasion were assessed separately. Accuracy, positive predictive value (PPV), and negative predictive value (NPV) were determined for CT alone and for CT supplemented with CT angiography. RESULTS: The accuracy, PPV, and NPV of helical CT with CT angiography in identifying venous invasion was 92% (33 of 36 patients), 86% (12 of 14 patients), and 95% (21 of 22 patients), respectively. When transverse CT images alone were analyzed, accuracy decreased to 69% (25 of 36 patients) (P =.005); PPV and NPV were 63% (five of eight patients) and 71% (20 of 28 patients), respectively. When identifying arterial invasion, the accuracy of CT with CT angiography and of CT alone was 86% (31 of 36 patients). PPV and NPV also were identical at 71% (five of seven patients) and 90% (26 of 29 patients), respectively. CONCLUSION: CT angiography significantly increases the ability to identify venous invasion when compared with CT alone but does not improve detection of arterial invasion.