Comparison between Gradient-Echo and Spin-Echo EPI MR Elastography at 3 T in quantifying liver stiffness of patients with and without iron overload; a prospective study.

OBJECTIVES: To compare the maximum axial area of the confidence mask and the calculated liver stiffness (LS) on gradient-echo (GRE) and spin-echo echo planar imaging (SE-EPI) MR elastography (MRE) in patients with and without iron deposition. METHODS: 104 patients underwent MRE by GRE and SE-EPI sequences at 3 T. R2* values >88 Hz in the liver were categorized in the iron overload group. The maximum axial area and the corresponding LS values were measured by manually contouring the whole area on one slice with the largest confidence mask at both GRE and SE-EPI sequences. RESULTS: In patients with iron overload, SE-EPI provided larger maximum axial confidence area in unfailed images (57.6 ± 41.7 cm2) compared to GRE (45.7 ± 29.1 cm2) (p-value = 0.007). In five patients with iron overload, imaging failed at GRE sequence, whereas at the SE-EPI sequence the maximum area of the confidence mask had a mean value of 33.5 ± 54.9 cm2. In livers without iron overload (R2*: 50.7 ± 13.1 Hz), the maximum area on the confidence mask was larger at SE-EPI (118.3 ± 41.2 cm2) than on GRE (105.1 ± 31.7 cm2) (P-value = 0.003). There was no significant difference in mean LS between SE-EPI (2.0 ± 0.3 kPa) and GRE (2.1 ± 0.5 kPa) in livers with iron overload (P value = 0.24). Similarly, in the group without iron overload, mean LS was 2.3 ± 0.7 kPa at SE-EPI and 2.4 ± 0.8 kPa at GRE sequences (P-value = 0.11). CONCLUSIONS: SE-EPI MRE can successfully provide similar LS measurements as GRE MRE. Furthermore, it provides a larger measurable area on the confidence mask in both groups with and without iron overload.

One-year survival and prognostic factors for survival among stroke patients: The PROVE-stroke study.

Background: Survival and prognostic factors following stroke occurrence differ between world regions. Studies investigating stroke features in the Middle-east region are scarce. We aimed to investigate 1-year survival and related prognostic factors of stroke patients in Central Iran. Materials and Methods: It is an observational analytical study conducted on patients registered in the Persian Registry of Cardiovascular Disease-Stroke (PROVE-Stroke) database. Records of 1703 patients admitted during 2015-2016 with the primary diagnosis of stroke in all hospitals of Isfahan, Iran were reviewed. Information regarding sociodemographic characteristics, clinical presentations, medications, and comorbidities were recorded. The living status of patients after 1 year from stroke was considered as 1-year survival. Results: Among 1345 patients with the final diagnosis of stroke, 970 (72.1%) were alive at the 1 year follow-up and the mean survival time based on Kaplan-Meier procedure was estimated 277.33 days. The hemorrhagic and ischemic types of stroke were reported in 201 (15.0%) and 1141 (84.8%) patients, respectively. Age (hazard ratio [HR] = 1.07, 95% confidence interval [CI] = 1.05-1.09), diabetes (HR = 1.49, 95% CI = 1.07-2.06), history of stroke or transient ischemic attack (HR = 1.81, 95% CI = 1.30-2.52), history of warfarin usage (HR = 1.73, 95% CI = 1.11-2.71), hospital complications of hemorrhage (HR = 3.89, 95% CI = 2.07-7.31), sepsis (HR = 1.78, 95% CI = 1.18-2.68), and hydrocephalus (HR = 3.43, 95% CI = 1.34-8.79), and modified Rankin Scale (mRS) ≥3 at the time of hospital dicharge (HR = 1.98, 95% CI = 1.27-3.07), were predictors of 1-year survival. Conclusion: Predictors of 1-year survival can be categorized into unchangeable ones, such as age, diabetes, previous stroke, and mRS. The changeable factors, such as hospital complications of infection and hemorrhage, guide physicians to pay greater attention to reduce the risk of mortality following stroke.

Does the change in volumetric functional MR metrics post-TACE predict histopathologic grading of hepatocellular carcinoma?

OBJECTIVES: To evaluate whether the change in volumetric ADC (vADC) and volumetric venous enhancement (vVE) after transarterial chemoembolization (TACE) can predict the histologic grading of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: This HIPPA-compliant retrospective study was approved by our institutional review board. The study population included 106 HCC patients (147 index lesions) who had MR imaging within 3 months before and after TACE and pathologic report of the HCC either by biopsy or liver transplantation/resection between 2001 and 2017. Volumetric measurements of venous enhancement (VE) and apparent diffusion coefficient (ADC) were performed on baseline and post-TACE MRI. The tumors were histologically classified into two low-grade and high-grade groups. The parameters between two groups were compared using bivariate and multivariate analyses. RESULTS: Median change in vADC, vVE, and absolute vADC skewness after TACE was higher in low-grade HCCs as compared with high-grade HCCs (p < 0.001, p = 0.005, p = 0.04, respectively). Combining ΔvADC, ΔvVE, and the etiology for background liver disease in multivariate analysis had the highest accuracy in distinguishing high-grade tumors (AUC = 91%). CONCLUSION: ΔvADC and ΔvVE after TACE are potential predictors of HCC histopathological grading. Combining functional MRI biomarkers with the etiology of liver disease can enhance the accuracy in assessing degree of differentiation. KEY POINTS: • Change in volumetric functional MRI biomarkers after TACE can be a non-invasive method to evaluate tumor histopathology in HCC. • The etiology of background liver disease might be a predictor of tumor degree of differentiation.

Advances in Imaging of Diffuse Parenchymal Liver Disease.

There are >1.5 billion people with chronic liver disease worldwide, causing liver diseases to be a significant global health issue. Diffuse parenchymal liver diseases, including hepatic steatosis, fibrosis, metabolic diseases, and hepatitis cause chronic liver injury and may progress to fibrosis and eventually hepatocellular carcinoma. As early diagnosis and treatment of these diseases impact the progression and outcome, the need for assessment of the liver parenchyma has increased. While the current gold standard for evaluation of the hepatic parenchymal tissue, biopsy has disadvantages and limitations. Consequently, noninvasive methods have been developed based on serum biomarkers and imaging techniques. Conventional imaging modalities such as ultrasound, computed tomography scan, and magnetic resonance imaging provide noninvasive options for assessment of liver tissue. However, several recent advances in liver imaging techniques have been introduced. This review article focuses on the current status of imaging methods for diffuse parenchymal liver diseases assessment including their diagnostic accuracy, advantages and disadvantages, and comparison between different techniques.

Imaging Features of Primary Sclerosing Cholangitis: From Diagnosis to Liver Transplant Follow-up.

Primary sclerosing cholangitis (PSC) is a chronic progressive inflammatory disease of the bile ducts that leads to multifocal bile duct fibrosis, strictures, cholestasis, liver parenchymal changes, and ultimately cirrhosis. It more commonly occurs in young adults, with a variety of clinical and imaging manifestations. The cause of the disease is not known, but it has a strong association with inflammatory bowel disease and can overlap with other autoimmune diseases, including autoimmune hepatitis and immunoglobulin G4-related disease. Patients are predisposed to various hepatic and extrahepatic deteriorating complications, such as bile duct and gallbladder calculi, acute bacterial cholangitis, liver abscess, and portal hypertension, as well as malignancies including cholangiocarcinoma (CCA), gallbladder cancer, and colorectal carcinoma. Imaging has an essential role in diagnosis, surveillance, and detection of complications. MR cholangiopancreatography and endoscopic retrograde cholangiopancreatography have high specificity and sensitivity for detection of primary disease and assessment of disease progression. However, many patients with PSC are still diagnosed incidentally at US or CT. Novel imaging techniques such as transient elastography and MR elastography are used to survey the grade of liver fibrosis. Annual cancer surveillance is necessary in all PSC patients to screen for CCA and gallbladder cancer. Familiarity with PSC pathogenesis and imaging features across various classic imaging modalities and novel imaging techniques can aid in correct imaging diagnosis and guide appropriate management. The imaging features of the biliary system and liver parenchyma in PSC across various imaging modalities are reviewed. Imaging characteristics of the differential diagnosis of PSC, clinical associations, and complications are described. Finally, the role of imaging in evaluation of PSC progression, pre-liver transplant assessment, and post-liver transplant disease recurrence are discussed.©RSNA, 2019.