Intravoxel incoherent motion diffusion-weighted imaging in the liver: comparison of mono-, bi- and tri-exponential modelling at 3.0-T.

PURPOSE: To determine whether a mono-, bi- or tri-exponential model best fits the intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) signal of normal livers. MATERIALS AND METHODS: The pilot and validation studies were conducted in 38 and 36 patients with normal livers, respectively. The DWI sequence was performed using single-shot echoplanar imaging with 11 (pilot study) and 16 (validation study) b values. In each study, data from all patients were used to model the IVIM signal of normal liver. Diffusion coefficients (Di ± standard deviations) and their fractions (fi ± standard deviations) were determined from each model. The models were compared using the extra sum-of-squares test and information criteria. RESULTS: The tri-exponential model provided a better fit than both the bi- and mono-exponential models. The tri-exponential IVIM model determined three diffusion compartments: a slow (D1 = 1.35 ± 0.03 × 10(-3) mm(2)/s; f1 = 72.7 ± 0.9 %), a fast (D2 = 26.50 ± 2.49 × 10(-3) mm(2)/s; f2 = 13.7 ± 0.6 %) and a very fast (D3 = 404.00 ± 43.7 × 10(-3) mm(2)/s; f3 = 13.5 ± 0.8 %) diffusion compartment [results from the validation study]. The very fast compartment contributed to the IVIM signal only for b values ≤15 s/mm(2) CONCLUSION: The tri-exponential model provided the best fit for IVIM signal decay in the liver over the 0-800 s/mm(2) range. In IVIM analysis of normal liver, a third very fast (pseudo)diffusion component might be relevant. KEY POINTS: • For normal liver, tri-exponential IVIM model might be superior to bi-exponential • A very fast compartment (D = 404.00 ± 43.7 × 10 (-3) mm (2) /s; f = 13.5 ± 0.8 %) is determined from the tri-exponential model • The compartment contributes to the IVIM signal only for b ≤ 15 s/mm(2).

Non-transplantable recurrence after percutaneous thermal ablation of ≤3-cm HCC: Predictors and implications for treatment allocation.

Percutaneous thermal ablation (PTA), resection, and liver transplantation are the standard curative options for hepatocellular carcinoma (HCC). Liver transplantation yields the best long-term outcomes but is limited by graft shortage. Thus, patients with ≤3-cm HCC are primarily treated by PTA even though recurrence is frequent and may occur outside transplant criteria. Data on non-transplantable recurrence (NTR) following PTA are lacking, however. We therefore investigated the incidence and predictors of NTR among 213 potentially transplantable patients (cirrhosis, 93%; Child-Pugh A, 98.6%; alcohol-related disease, 62%) with ≤3-cm HCC(s) treated by PTA, to stratify them according to their NTR risk and to improve treatment allocation. During follow-up (median: 41.2 months), NTR occurred in 18.3% (alpha-fetoprotein [AFP] model) and 23% (Milan) patients. NTR prediction with competing-risk analysis and internal validation revealed AFP > 100 ng/ml (subdistribution hazard ratio: 7.28; p < 0.001) and prior HCC (subdistribution hazard ratio: 3.77; p = 0.002) as independent predictors (Harrell's C: 0.76). Based on this model using the AFP score (equally predictive within Milan criteria), patients were stratified into three NTR risk categories: HCC-naïve with AFP < 100 ng/ml (low risk, n = 108 of 213), non-HCC naïve with AFP < 100 ng/ml (intermediate risk, n = 92 of 213), AFP ≥ 100 ng/ml (high risk, n = 13 of 213), among whom 9.3% (3.7% [Milan]), 22.8% (25% [Milan]), and 61.5% (38/5% [Milan]) presented NTR (p < 0.001). Median recurrence-free survival was 4.6, 14.5, and 43.4 months, respectively, in high-risk, intermediate-risk, and low-risk categories (p < 0.001). Median overall survival, which was 19.1 months in high-risk patients, was not reached otherwise (p < 0.001). Conclusion: Overall, PTA of ≤3-cm HCC incurs a low NTR risk. Simple and noninvasive predictors (HCC naivety, AFP) accurately stratified patients' risk of NTR, and should help to improve treatment allocation. Patients with AFP ≥ 100 ng/ml have a high risk of NTR, poor recurrence-free survival, and overall survival. Further studies evaluating preemptive transplantation or adjuvant/neoadjuvant strategies are highly needed in this small patient subset.

Inferior mesenteric arteriovenous fistula with colonic ischemia: a case report and review of the literature.

Inferior mesenteric arteriovenous fistula is a rare abnormal high flow communication with only 40 primary and secondary cases reported in literature. Shunting of arterial flow through the inferior mesenteric vein to the portal system can cause a variety of nonspecific clinical signs and symptoms usually associated with the diagnosis of arteriovenous malformation. Symptom intensities are flow-dependent and can range from minimal abdominal symptoms to severe heart failure due to left to right shunt. We report the case of a 72-year-old man without past history of abdominal surgery or trauma who was referred to our department for a 2-month history of intermittent diarrhea and abdominal pain caused by an arteriovenous fistula involving the left colic artery and the inferior mesenteric vein. A progressive and spontaneous improvement of symptoms and a control CT scan that confirmed the reduction of venous vascular engorgement and regression of parietal thickening of the left and sigmoid colon permitted a non-operative management.Inferior mesenteric arteriovenous fistula can be a rare cause of ischemic colitis and, if necessary, an appropriate treatment based on high clinical suspicion can reduce the risk of complications related to a missed diagnosis.

Multimodal Percutaneous Thermal Ablation of Small Hepatocellular Carcinoma: Predictive Factors of Recurrence and Survival in Western Patients.

BACKGROUND: To identify the predictive factors of recurrence and survival in an unselected population of Western patients who underwent multimodal percutaneous thermal ablation (PTA) for small Hepatocellular Carcinomas (HCCs). METHODS: January 2015-June 2019: data on multimodal PTA for <3 cm HCC were extracted from a prospective database. Local tumor progression (LTP), intrahepatic distant recurrence (IDR), time-to-LTP, time-to-IDR, recurrence-free (RFS) and overall (OS) survival were evaluated. RESULTS: 238 patients underwent 317 PTA sessions to treat 412 HCCs. During follow-up (median: 27.1 months), 47.1% patients had IDR and 18.5% died. LTP occurred after 13.3% of PTA. Tumor size (OR = 1.108, p < 0.001; hazard ratio (HR) = 1.075, p = 0.002) and ultrasound guidance (OR = 0.294, p = 0.017; HR = 0.429, p = 0.009) independently predicted LTP and time-to-LTP, respectively. Alpha fetoprotein (AFP) > 100 ng/mL (OR = 3.027, p = 0.037) and tumor size (OR = 1.06, p = 0.001) independently predicted IDR. Multinodular HCC (HR = 2.67, p < 0.001), treatment-naïve patient (HR = 0.507, p = 0.002) and AFP > 100 ng/mL (HR = 2.767, p = 0.014) independently predicted time-to-IDR. RFS was independently predicted by multinodular HCC (HR = 2.144, p = 0.001), treatment naivety (HR = 0.546, p = 0.004) and AFP > 100 ng/mL (HR = 2.437, p = 0.013). The American Society of Anesthesiologists (ASA) score > 2 (HR = 4.273, p = 0.011), AFP (HR = 1.002, p < 0.001), multinodular HCC (HR = 3.939, p = 0.003) and steatotic HCC (HR = 1.81 × 10-16, p < 0.001) independently predicted OS. CONCLUSIONS: IDR was associated with tumor aggressiveness, suggesting a metastatic mechanism. Besides AFP association with LTP, IDR, RFS and OS, treatment-naïve patients had longer RFS, and multi-nodularity was associated with shorter RFS and OS. Steatotic HCC, identified on pre-treatment MRI, independently predicted longer OS, and needs to be further explored.

Airway malacia in chronic obstructive pulmonary disease: prevalence, morphology and relationship with emphysema, bronchiectasis and bronchial wall thickening.

The aim of this study was to determine the prevalence of airway malacia and its relationship with ancillary morphologic features in patients with chronic obstructive pulmonary disease (COPD). A retrospective review was performed of a consecutive series of patients with COPD who were imaged with inspiratory and dynamic expiratory multidetector computed tomography (MDCT). Airway malacia was defined as > or =50% expiratory reduction of the airway lumen. Both distribution and morphology of airway malacia were assessed. The extent of emphysema, extent of bronchiectasis and severity of bronchial wall thickness were quantified. The final study cohort was comprised of 71 patients. Airway malacia was seen in 38 of 71 patients (53%), and such proportion was roughly maintained in each stage of COPD severity. Almost all tracheomalacia cases (23/25, 92%) were characterised by an expiratory anterior bowing of the posterior membranous wall. Both emphysema and bronchiectasis extent did not differ between patients with and without airway malacia (p > 0.05). Bronchial wall thickness severity was significantly higher in patients with airway malacia and correlated with the degree of maximal bronchial collapse (p < 0.05). In conclusion, we demonstrated a strong association between airway malacia and COPD, disclosing a significant relationship with bronchial wall thickening.

Challenging TIPS in Liver Transplant Recipients: The Pull-Through Technique to Address Piggyback Anastomosis.

PURPOSE: The hepatic vein access during transjugular intrahepatic portosystemic shunt (TIPS) can be challenging in liver transplant recipient patients, especially when piggyback anastomosis was performed. We described a modified technique and reviewed the clinical outcomes of TIPS in transplanted patients. MATERIALS AND METHODS: From 2015 to 2016, 8 patients with history of liver transplantation using a three-hepatic vein piggyback technique for venous anastomosis underwent a TIPS in our institution. Indications were refractory ascites (n = 7) or variceal bleeding (n = 1). When the hepatic vein access failed via the standard jugular route, a pull-through technique was used: After puncturing the right hepatic vein under ultrasound guidance, a guidewire and a vascular sheath were advanced, then the guidewire was snared in the inferior vena cava and retrieved though the jugular access, and the hepatic vein was catheterized along the guidewire. The safety and technical success rates of this technique and the clinical outcomes of the study population were retrospectively assessed. RESULTS: Seven of 8 patients (87.5%) required the pull-through technique to access a hepatic vein. No complications of the percutaneous access of the hepatic vein were found at the one-day and one-month ultrasound Doppler examinations. Among 7 patients who had refractory ascites, 3 had complete resolution of ascites (43%), and one had moderate improvement. One patient with refractory infected ascites on severe graft failure and one with massive bleeding died soon after the procedure. CONCLUSION: A pull-through technique following percutaneous puncture of a hepatic vein is a safe technique for performing a TIPS in liver transplant recipients with piggyback anastomosis complicated by acute hepatic vein angulation.

Interventional oncology for hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and is increasing in incidence. The overall prognosis of patients with liver cancer is poor. The Barcelona Clinic Liver Cancer (BCLC) classification in 5 stages is endorsed by European Association for the Study of the Liver (EASL) and American Association for the Study of Liver Disease (AASLD). This classification is recommended for treatment allocation. Because a small proportion of patients are suitable for curative surgical treatment, various locoregional therapies are widely used to manage patients with HCC. The image-guided therapies, also called interventional radiology or interventional oncology (IO) techniques consisted in percutaneous or endovascular approach. This article reviews the different IO treatments available in HCC patients and the strength of the data.