CT perfusion in stroke: Comparing conventional and RAPID automated software.

CT perfusion (CTP) imaging is increasingly used for routine evaluation of acute ischemic stroke. Knowledge about the different types of CTP software, imaging acquisition and post-processing, and interpretation is crucial for appropriate patient selection for reperfusion therapy. Conventional vendor-provided CTP software differentiates between ischemic penumbra and core infarct using the tiebreaker of critically reduced cerebral blood volume (CBV) values within brain regions showing abnormally elevated time parameters like mean transit time (MTT) or time to peak (TTP). On the other hand, RAPID automated software differentiates between ischemic penumbra and core infarct using the tiebreaker of critically reduced cerebral blood flow (CBF) values within brain regions showing abnormally elevated time to maximum (Tmax). Additionally, RAPID calculates certain indices that confer prognostic value, such as the hypoperfusion and CBV index. In this review, we aim to familiarize the reader with the technical principles of CTP imaging, compare CTP maps generated by conventional and RAPID software, and discuss important thresholds for reperfusion and prognostic indices. Lastly, we discuss common pitfalls to help with the accurate interpretation of CTP imaging.

Role of MRI-Derived Radiomics Features in Determining Degree of Tumor Differentiation of Hepatocellular Carcinoma.

Background: To investigate radiomics ability in predicting hepatocellular carcinoma histological degree of differentiation by using volumetric MR imaging parameters. Methods: Volumetric venous enhancement and apparent diffusion coefficient were calculated on baseline MRI of 171 lesions. Ninety-five radiomics features were extracted, then random forest classification identified the performance of the texture features in classifying tumor degree of differentiation based on their histopathological features. The Gini index was used for split criterion, and the random forest was optimized to have a minimum of nine participants per leaf node. Predictor importance was estimated based on the minimal depth of the maximal subtree. Results: Out of 95 radiomics features, four top performers were apparent diffusion coefficient (ADC) features. The mean ADC and venous enhancement map alone had an overall error rate of 39.8%. The error decreased to 32.8% with the addition of the radiomics features in the multi-class model. The area under the receiver-operator curve (AUC) improved from 75.2% to 83.2% with the addition of the radiomics features for distinguishing well- from moderately/poorly differentiated HCCs in the multi-class model. Conclusions: The addition of radiomics-based texture analysis improved classification over that of ADC or venous enhancement values alone. Radiomics help us move closer to non-invasive histologic tumor grading of HCC.

Can Posttransarterial Chemoembolization Volumetric Oil Deposition on Computed Tomography Predict Treatment Response on Magnetic Resonance Imaging in Leiomyosarcoma Metastases to the Liver?

OBJECTIVE: To predict early tumor response to transarterial chemoembolization (TACE) based on volumetric oil deposition on posttreatment computed tomography (CT) in patients with leiomyosarcoma liver metastases. METHODS: This retrospective lesion-by-lesion based study included 32 lesions. The volumetric percent enhancing tumor on pre-TACE and 1-month post-TACE venous phase magnetic resonance imaging (MRI), and the percent oil deposition on CT 1 day after TACE were calculated. The predicted post-TACE enhanced percentage was computed by subtracting percent oil deposition from baseline percent enhanced. RESULTS: Mean percentage of viable tumor on pre-TACE MRI was 90.6% ± 9.3%. Mean oil deposition was calculated as 51.4% ± 26.2%. Mean percentage of measured residual tumor enhancement 1 month after TACE was 58.3% ± 27%, which correlates with predicted enhancement percentage of 43.9% ± 25.1% (r = 0.72, P < 0.001). A threshold of 35.5% for enhancement reduction was determined to predict tumor response with an accuracy of 78.1%. CONCLUSION: Volumetric oil deposition on CT can predict residual enhancement on post-TACE MRI.

Integrating baseline MR imaging biomarkers into BCLC and CLIP improves overall survival prediction of patients with hepatocellular carcinoma (HCC).

OBJECTIVES: We aimed to evaluate the independent predictive role of baseline imaging biomarkers for overall survival (OS) and transplant-free survival (TFS) in patients with HCC and assess the incremental value of these biomarkers to current staging systems. METHODS: In this retrospective IRB approved study, the clinical, laboratory, and imaging parameters of 304 HCC patients were collected. Cox regression model was utilized to identify the potential predictors of survival. Recursive partitioning test was utilized to identify the optimal ADC cutoff for stratifying patients' OS. Patients were stratified based on Barcelona Clinic Liver Cancer (BCLC) and Cancer of the Liver Italian Program (CLIP). Binary ADC value (above vs. below the cutoff) and tumor margin (well- vs. ill-defined) were integrated into BCLC and CLIP. OS and TFS was compared for patients based on standard criteria with and without imaging biomarkers. RESULTS: At baseline, patients with low tumor ADC and well-defined tumor margin (favorable imaging biomarkers) had longer survival, as compared to those with high ADC and ill-defined tumor margin (unfavorable imaging biomarkers) (median OS of 43 months vs. 7 months, respectively) (p < 0.001). Tumor ADC and tumor margin remained strong independent predictors of survival after adjustment for demographics, BCLC and CLIP staging, and tumor burden. Incorporating ADC and tumor margin improved performance of OS prediction by 9% in BCLC group and 6% in CLIP group. CONCLUSION: Incorporating ADC and tumor margin to current staging systems for HCC significantly improve prediction of OS and TFS of these criteria. KEY POINTS: • ADC and tumor margin are predictors of overall survival in HCC patients, independent of clinical, laboratory, and other imaging variables. • Adding ADC and tumor margin improved the prognostic value of BCLC and CLIP criteria by 9% and 6%, respectively. • High ADC and ill-defined tumor margin at baseline predicted poor survival, regardless of patient's liver function and general health status.

Post-TACE changes in ADC histogram predict overall and transplant-free survival in patients with well-defined HCC: a retrospective cohort with up to 10 years follow-up.

OBJECTIVES: To evaluate the role of change in apparent diffusion coefficient (ADC) histogram after the first transarterial chemoembolization (TACE) in predicting overall and transplant-free survival in well-circumscribed hepatocellular carcinoma (HCC). METHODS: Institution database was searched for HCC patients who got conventional TACE during 2005-2016. One hundred four patients with well-circumscribed HCC and complete pre- and post-TACE liver MRI were included. Volumetric MRI metrics including tumor volume, mean ADC, skewness, and kurtosis of ADC histograms were measured. Univariate and multivariable Cox models were used to test the independent role of change in imaging parameters to predict survival. P values < 0.05 were considered significant. RESULTS: In total, 367 person-years follow-up data were analyzed. After adjusting for baseline liver function, tumor volume, and treatment modality, incremental percent change in ADC (ΔADC) was an independent predictor of longer overall and transplant-free survival (p = 0.009). Overall, a decrease in ADC-kurtosis (ΔkADC) showed a strong role in predicting longer survival (p = 0.021). Patients in the responder group (ΔADC ≥ 35%) had the best survival profile, compared with non-responders (ΔADC < 35%) (p < 0.001). ΔkADC, as an indicator of change in tissue homogeneity, could distinguish between poor and fair survival in non-responders (p < 0.001). It was not a measure of difference among responders (p = 0.244). Non-responders with ΔkADC ≥ 1 (homogeneous post-TACE tumor) had the worst survival outcome (HR = 5.70, p < 0.001), and non-responders with ΔkADC < 1 had a fair survival outcome (HR = 2.51, p = 0.029), compared with responders. CONCLUSIONS: Changes in mean ADC and ADC kurtosis, as a measure of change in tissue heterogeneity, can be used to predict overall and transplant-free survival in well-circumscribed HCC, in order to monitor early response to TACE and identify patients with treatment failure and poor survival outcome. KEY POINTS: • Changes in the mean and kurtosis of ADC histograms, as the measures of change in tissue heterogeneity, can be used to predict overall and transplant-free survival in patients with well-defined HCC. • A ≥ 35% increase in volumetric ADC after TACE is an independent predictor of good survival, regardless of the change in ADC histogram kurtosis. • In patients with < 35% ADC change, a decrease in ADC histogram kurtosis indicates partial response and fair survival, while ∆kurtosis ≥ 1 correlates with the worst survival outcome.

Role of volumetric multiparametric MRI in distinguishing between intraductal papillary mucinous neoplasms and serous cystadenoma.

PURPOSE: To evaluate the use of volumetric multiparametric MRI in differentiating pancreatic intraductal papillary mucinous neoplasms (IPMNs) from serous cystadenomas (SCAs) METHODS: Included patients (123 patients with pancreatic cystic neoplasms (PCNs) measuring ≥ 10 mm) were stratified into two groups based on cyst type. Axial cyst size, region of interest (ROI)-based apparent diffusion coefficient (ADC) and volumetric data, including cyst volume, volumetric apparent diffusion coefficient (vADC), and volumetric venous enhancement (vVE) were extracted and compared between the two groups. Univariate and multiple logistic regression was used to develop models for distinguishing between IPMNs and SCAs. RESULTS: Volume and size of the cysts, vVE and vADC and ROI-ADC were significantly different between the two groups. Cyst volume was significantly larger in SCAs (median = 14.1cm3, IQR 3.5-42.5) than in IPMNs (median = 2.5 cm3, IQR 1.1-6) (p < 0.001). IPMNs had a higher volumetric ADC value in comparison to SCAs (2925 ± 294 × 10-6 mm2/s vs 2521 ± 202 × 10-6 mm2/s, p < 0.001). However, IPMNs had lower vVE values compared to SCAs (37 signal intensity (SI) vs 86 SI, p < 0.001). Area under the ROC Curve (AUC) of the model that included vADC and cyst volume had 95% accuracy in distinguishing between the two groups. In comparison, the AUC of the model that included ROI-ADC and axial cyst size had 84% accuracy in distinguishing between the two groups. A threshold of 2615 × 10-6 mm2/s for volumetric ADC resulted in the identification of IPMNs from SCAs with sensitivity and specificity of 90.8% and 73.5%, respectively. CONCLUSION: IPMNs had smaller cyst volume, higher volumetric ADC and lower volumetric VE values compared to SCAs. Volumetric multiparametric MRI could be useful in differentiating between the IPMN and SCA groups.

Role of tumor margin and ADC change in defining the need for additional treatments after the first TACE in patients with unresectable HCC.

PURPOSE: To define the number of TACE sessions needed to improve patients' overall survival (OS) in different subgroups of unresectable HCC. METHODS: This retrospective cohort included 180 patients who got TACE between 2005-2016 as the initial treatment for unresectable HCC. Tumor margin (well- vs. ill-defined) was determined by two radiologists at baseline. Well-defined group was divided into two groups (ADC-responders vs. ADC-nonresponders) based on %ADC change (ΔADC-cutoff = 25 %). Accordingly, patients were categorized into three groups, ill-defined, well-defined ADC-responders, or well-defined ADC-nonresponders. Cox-analysis was used to compare the survival benefit of multiple TACE in different groups. RESULTS: Ill-defined HCC (n = 108) was associated with worse survival (HR = 1.95,p < 0.001). Multiple TACE were associated with increased OS (HR = 0.88,p = 0.033) in these patients, with significant survival improvement after ≥4TACE. ΔADC was not related to OS in ill-defined group. In well-defined group (n = 72), multiple TACE were not associated with improved OS (HR = 0.181,p = 0.090). These patients were categorized into two groups based on ΔADC-cutoff. ADC-responders (ΔADC≥25 %) had the longest survival than other groups(p = 0.015). Multiple TACE sessions were not associated with better OS in this group (HR = 1.004,p = 0.982). By contrast, incremental number of TACE were associated with significantly longer OS in ADC-nonresponders (ΔADC<25 %) (HR = 0.79,p = 0.034). These patients' OS significantly improved after ≥3TACE. CONCLUSION: The survival benefit of sequential TACE sessions varies for different HCC subgroups. There was no significant survival benefit associated with multiple TACE in well-defined lesions responding to the first TACE. The most survival benefit was for ADC-nonresponder well-defined group and it was least for ill-defined HCC group, regardless of ADC-response.

Cross-sectional imaging in patients with primary sclerosing cholangitis: Single time-point liver or spleen volume is associated with survival.

AIM: To evaluate the association between single time-point quantitative liver and spleen volumes in patients with PSC and transplant-free survival, independent of Mayo risk score. MATERIALS AND METHODS: This HIPAA-compliant retrospective study included 165 PSC patients in a hospital. Total (T), and lobar (right [R], left [L], and caudate [C]) liver volumes and spleen volume (S) were measured. Adverse outcome was identified as being on liver transplantation list, transplantation or death (outcome 1), and transplantation or death (outcome 2). Cox-regression was performed to assess the predictive value of volumetric parameters to predict transplant-free survival with and without Mayo risk score. Stratified analysis by Mayo risk score categories was performed to assess the discriminative value of volumes in the model. Prediction models were developed dependent of Mayo score, based on patients demographics, lab values and volumetric measures for both defined outcomes. Kaplan-Meier curves were depicted for different liver and spleen volumes. P value <0.05 was considered statistically significant. RESULTS: In this cohort (age 43 ±â€¯17 years; 59 % men) 51 % of patients had adverse outcome. Cox-regression analysis demonstrated statistically significant association between values of T, L, R, C, S, L/T, and C/T and outcome 1; and also statistically significant association between values C, S, and C/T and outcome 2. Prediction models included age, INR, total bilirubin, AST, variceal bleeding, S, and C for outcome 1 and age, INR, total bilirubin, AST, variceal bleeding, and S for outcome 2. CONCLUSIONS: Based on our observational study, quantitative liver and spleen volumes may be associated with transplant-free survival in patients with PSC and may have the potential for predicting the outcome but this should be validated by randomized clinical trial studies.

Therapeutic response assessment in pancreatic ductal adenocarcinoma: society of abdominal radiology review paper on the role of morphological and functional imaging techniques.

Pancreatic ductal adenocarcinoma (PDA) is the third leading cause of cancer-related death in the United States and is projected to be the second by 2030. Systemic combination chemotherapy is considered an essential first-line treatment for the majority of patients with PDA, in both the neoadjuvant and palliative settings. In addition, a number of novel therapies are being tested in clinical trials for patients with advanced PDA. In all cases, accurate and timely assessment of treatment response is critical to guide therapy, reduce drug toxicities and cost from a failing therapy, and aid adaptive clinical trials. Conventional morphological imaging has significant limitations, especially in the context of determining primary tumor response and resectability following neoadjuvant therapies. In this article, we provide an overview of current therapy options for PDA, highlight several morphological imaging findings that may be helpful to reduce over-staging following neoadjuvant therapy, and discuss a number of emerging imaging, and non-imaging, tools that have shown promise in providing a more precise quantification of disease burden and treatment response in PDA.

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.

Role of baseline volumetric functional MRI in predicting histopathologic grade and patients' survival in hepatocellular carcinoma.

OBJECTIVES: We aimed to evaluate the role of volumetric ADC (vADC) and volumetric venous enhancement (vVE) in predicting the grade of tumor differentiation in hepatocellular carcinoma (HCC). METHODS: The study population included 136 HCC patients (188 lesions) who had baseline MR imaging and histopathological report. Measurements of vVE and vADC were performed on baseline MRI. Tumors were histologically classified into low-grade and high-grade groups. The parameters between the two groups were compared using Mann-Whitney U and chi-square tests for continuous and categorical parameters, respectively. Area under receiver operating characteristic (AUROC) was calculated to investigate the accuracy of vADC and vVE. Logistic regression and multivariable Cox regression were used to unveil the potential parameters associated with high-grade HCC and patient's survival, respectively. RESULTS: Lesions with higher vADC values and a higher absolute vADC skewness were more likely to be high grade on histopathology assessment (p = 0.001 and p = 0.0291, respectively). Also, vVE showed a trend to be higher in low-grade lesions (p = 0.079). Adjusted multivariable model including vADC, vVE, and vADC skewness could strongly predict HCC degree of differentiation (AUROC = 83%). Additionally, a higher Child-Pugh score (HR = 2.39 [p = 0.02] for score 2 and HR = 3.47 [p = 0.001] for score 3), vADC skewness (HR = 1.52, p = 0.02; per increments in skewness), and tumor volume (HR = 1.1, p = 0.001; per 100 cm3 increments) showed the highest association with patients' survival. CONCLUSIONS: vADC and vVE have the potential to accurately predict HCC differentiation. Additionally, some imaging features in combination with patients' clinical characteristics can predict patient survival. KEY POINTS: • Volumetric functional MRI metrics can be considered as non-invasive measures for determining tumor histopathology in HCC. • Estimating patient survival based on clinical and imaging parameters can be used for modifying management approach and preventing unnecessary adverse events.

Comparison between ROI-based and volumetric measurements in quantifying heterogeneity of liver stiffness using MR elastography.

OBJECTIVES: This study was conducted to quantify the heterogeneity of liver stiffness (LS) on MR elastography (MRE) by comparing ROI-based and volumetric measurements. METHODS: LS was measured by ROI-based and volumetric segmentation of the liver parenchyma. Mean LS (MLS) was calculated and used to assign stages of fibrosis. Volumetric measurements of stiffness maps were used to determine the percentage of liver volume above/below MLS and presence of LS heterogeneity. Heterogeneous stiffness was defined when the first and second most predominant stages were more than one category apart. MLS values by each method were compared using the Wilcoxon signed-rank test. RESULTS: We included 128 patients with suspected liver fibrosis (mean age 54.4 ± 14.8 years). MLS was 2.7 ± 1.0 kPa for ROI measurements and 2.6 ± 0.9 kPa for the volumetric method (p = 0.001). Of 59 patients with normal stage (F0), 31 patients (52.5%) had > 20% of liver volume with abnormal LS (F1-F4). Heterogeneous LS was reported in 18 patients (14%). CONCLUSIONS: MLS measurement may not represent the entire spectrum of hepatic fibrosis. Volumetric segmentation may potentially improve the detection of heterogeneous fibrosis and the accuracy of LS measurement. KEY POINTS: • Heterogeneity of hepatic fibrosis may occur in patients with chronic liver disease. • MR elastography is used to assess hepatic fibrosis by measuring liver stiffness. • Measuring liver stiffness by the ROI method and reporting a mean value may fail to detect heterogeneity of hepatic fibrosis. Volumetric assessment of liver stiffness by MR elastography may detect heterogeneity of parenchymal involvement.

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.

Follow-up of Incidentally Detected Pancreatic Cystic Neoplasms: Do Baseline MRI and CT Features Predict Cyst Growth?

Background Incidental detection of pancreatic cystic neoplasm (PCN) has increased. Since a small percentage of PCNs possess malignant potential, management is challenging. The recently revised American College of Radiology (ACR) recommendations define PCN measurement and growth for different categories based on baseline cyst size. However, no data are available regarding PCN growth rate under the ACR-defined size categories. Purpose To assess growth of incidentally detected PCNs on long-term imaging follow-up using revised ACR recommendations and to evaluate the association between baseline imaging features and growth. Materials and Methods This retrospective study included PCNs with baseline imaging performed between January 2002 and May 2017, with two or more cross-sectional imaging studies performed at least 12 months apart. PCN assessment was based on ACR 2017 recommendations. Cyst features, including location, septations, and mural nodules and multiplicity, were noted. Time to cyst progression (growth by ACR criteria) was examined by using baseline PCN size, among other factors. Results A total of 646 cysts in 390 patients were followed up for a median of 50 months (range, 12-186 months). A total of 184 (28.5%) cysts increased in size, 52 (8.1%) decreased in size, and 410 (63.4%) remained stable. For groups in which baseline PCN size was smaller than 5 mm, 5-14 mm, 15-25 mm, and larger than 25 mm, growth was noted in seven (13.2%), 106 (28.9%), 49 (32.2%), and 22 (29.7%) cysts, respectively. ACR baseline size categories (subhazard ratio: 2.8 [5-14-mm PCN group], 3.4 [15-25-mm PCN group], and 2.7 [>25 mm group], as compared with the <5 mm PCN group; P < .05 for each) demonstrated association with growth. Presence of mural nodules, septations, or lesion multiplicity failed to demonstrate association with growth. Among PCNs smaller than 5 mm at baseline, 100% of PCNs at 3-year follow-up and 94.2% of PCNs at 5-year follow-up were likely to remain stable. Conclusion American College of Radiology baseline size category of 15-25-mm pancreatic cystic neoplasms (PCNs) demonstrated the highest (3.1 times) likelihood of growth, as compared with the category of PCNs smaller than 5 mm. PCNs smaller than 5 mm at baseline did not demonstrate growth at 3-year imaging follow-up. © RSNA, 2019 Online supplemental material is available for this article.

Semi-quantitative visual assessment of hepatic tumor burden can reliably predict survival in neuroendocrine liver metastases treated with transarterial chemoembolization.

OBJECTIVES: To evaluate the accuracy and reproducibility of semi-quantitative visual assessment of hepatic tumor burden (HTB) on MRI and to investigate its prognostic value in predicting overall survival (OS) in neuroendocrine liver metastases (NELMs) treated with transarterial chemoembolization (TACE). METHODS: Three independent readers blinded to the quantitative HTB measurement reviewed baseline MRI in 111 NELM patients treated with TACE. Readers visually assessed and semi-quantitatively categorized HTB using the European Neuroendocrine Tumor Society (ENETS) guidelines. Quantitative HTB measured by manual segmentation was used as the reference standard. Agreements between quantitative and semi-quantitative measurement of HTB, as well as intra- and inter-reader reproducibility, were evaluated using weighted kappa coefficient and intraclass correlation coefficient (ICC). Survival analysis included the Kaplan-Meier curves and Cox regression. Harrell C-index was calculated to evaluate the prognostic value of semi-quantitative HTB for predicting OS. RESULTS: According to quantitative HTB, 41, 29, 25, and 16 patients were categorized into ≤ 10%, 11-25%, 26-50%, and > 50% groups, respectively. Agreements between quantitative and semi-quantitative measurement of HTB by each reader (weighted kappa, 0.82-0.96), intra-reader agreement (weighted kappa, 0.95), and inter-reader agreements (weighted kappa, 0.84-0.91; ICC, 0.98) were at least substantial to almost perfect. Semi-quantitative HTB was an independent prognostic factor in NELMs treated with TACE (multivariate Cox regression, p < 0.001), with prognostic value comparable to that of quantitative HTB (Harrell C-index, 0.735 for both semi-quantitative and quantitative HTB in multivariate regression). CONCLUSION: Semi-quantitative visual assessment of HTB using MRI is accurate and reproducible and could reliably predict OS in NELMs treated with TACE. KEY POINTS: • Semi-quantitative visual assessment of HTB using MR imaging is considerably accurate, reproducible, and efficient. • Visually assessed semi-quantitative HTB serves as an independent predictor of OS in NELMs treated with TACE.

Prognostic value of baseline volumetric multiparametric MR imaging in neuroendocrine liver metastases treated with transarterial chemoembolization.

OBJECTIVES: To determine whether baseline multiparametric MR imaging can predict overall survival (OS) and hepatic progression-free survival (HPFS) in patients with neuroendocrine liver metastases (NELMs) treated with transarterial chemoembolization (TACE). METHODS: This retrospective study included 84 NELMs patients treated with TACE. Tumor volume and volumetric measurements of arterial enhancement (AE), venous enhancement (VE), and apparent diffusion coefficient (ADC) were performed on baseline MR imaging. A maximum of one, two, and five index lesions were selected in each patient. OS was the primary endpoint and HPFS was the secondary endpoint. Prognostic values of volumetric multiparametric MR parameters for predicting OS and HPFS considering a maximum of one, two, and five index lesions were assessed. RESULTS: Prognostic values of volumetric multiparametric MR parameters for predicting OS and HPFS were similar regardless of the maximum number of index lesions. Multivariate survival analysis showed that baseline dominant tumor volume ≥ 73 cm3, volumetric mean AE ≥ 45%, and mean VE ≥ 73% were independent prognostic factors for OS (HR 2.73; 95% CI 1.45, 5.15; HR 0.32; 95% CI 0.17, 0.63; HR 0.35; 95% CI 0.17, 0.72, respectively) and HPFS (HR 2.30, 95% CI 1.38, 3.84; HR 0.46, 95% CI 0.25, 0.84; HR 0.36, 95% CI 0.19, 0.57, respectively). OS and HPFS were similar in patients with low and high volumetric mean ADC. CONCLUSION: Volumetric enhancement values and tumor volume of the dominant lesion on baseline MR imaging may act as prognostic factors for OS and HPFS in NELMs patients treated with TACE. KEY POINTS: • High volumetric mean AE and VE, and low tumor volume of the dominant lesion on baseline MR imaging were associated with favorable OS and HPFS in NELMs patients treated with TACE. • Evaluation of multiple lesions does not provide additional information as compared to single lesion evaluation.

Correlation between quantitative liver and spleen volumes and disease severity in primary sclerosing cholangitis as determined by Mayo risk score.

OBJECTIVES: To correlate total and lobar liver and spleen volume with disease severity in primary sclerosing cholangitis (PSC) as determined by Mayo risk score. METHODS: This HIPAA-compliant single center retrospective study included 147 PSC patients with available imaging studies (MRCP/CT) and laboratory data between January 2003 and January 2018. Total and lobar (right, left and caudate) liver volume and spleen volume were measured. ANOVA test was performed to assess the differences in volumes between low, intermediate and high-risk groups (Mayo risk score <0, >0 and <2, >2, respectively). Correlations between volumes and Mayo risk score were calculated. ROC analysis was performed to assess the accuracy of the variable with the strongest correlation to PSC severity to predict Mayo risk score. P value <0.05 was considered statistically significant. RESULTS: The mean age of this cohort was 45 ± 17 years; 58% were men. Absolute volumes of left lobe, caudate and spleen and volume ratios of left lobe and caudate to total liver volume of the high-risk group were significantly higher compared to those of low and intermediate risk groups (p < 0.05). Left lobe to total liver volume ratio had the highest correlation to Mayo risk score (Pearson correlation coefficient 0.61, p < 0.05) and on ROC analysis it had 84.4% accuracy in detecting high-risk PSC. CONCLUSIONS: In this single institution large cohort study, the left lobe to total liver volume ratio was the best quantifiable volumetric biomarker to correlate with severity of PSC as identified by Mayo risk score.

Baseline Volumetric Multiparametric MRI: Can It Be Used to Predict Survival in Patients with Unresectable Intrahepatic Cholangiocarcinoma Undergoing Transcatheter Arterial Chemoembolization?

Purpose To evaluate whether baseline MRI can help predict survival in patients with unresectable intrahepatic cholangiocarcinoma (ICCA) undergoing transcatheter arterial chemoembolization (TACE). Materials and Methods This retrospective study was compliant with HIPAA and approved by the institutional review board. The requirement to obtain informed consent was waived. The study included 111 patients (mean age, 62 years ± 12; range, 29-86 years), with 44 men (mean age, 61 years ± 12; range, 29-81 years) and 67 women (mean age, 63 years ± 12; range, 34-86 years). Patients underwent TACE after baseline MRI, which included contrast-enhanced and diffusion-weighted imaging with apparent diffusion coefficient (ADC) mapping between 2003 and 2016. The single largest tumor was assessed independently by a radiologist for anatomic and functional (viable tumor volume, percentage viable tumor volume [100 × viable tumor volume/whole tumor volume], viable tumor burden [100 × viable tumor volume/whole liver volume], and ADC) parameters. Survival analysis was performed with Kaplan-Meier and Cox regression analysis. Results Overall survival (OS) was higher with a baseline ADC of 1415 × 10-6 mm2/sec or less compared with greater than 1415 × 10-6 mm2/sec (P = .005; 25th percentile of OS, 17 months vs 7 months, respectively), percentage viable tumor volume greater than 90% compared with 90% or less (P = .001; 25th percentile of OS, 20 months vs 7 months, respectively), and viable tumor burden greater than 6.6% compared with 6.6% or less (P = .09; 25th percentile of OS, 17 months vs 7 months, respectively). Baseline ADC greater than 1415 × 10-6 mm2/sec (hazard ratio [HR]: 2.176 [95% confidence interval: 1.217, 3.891]; P = .009) and percentage viable tumor volume greater than 90% (HR: 0.319 [95% confidence interval: 0.148, 0.685]; P = .003) were associated with OS independent of clinical confounders (age and sex). At multiparametric MRI risk stratification (with low ADC and high percentage viable tumor volume considered favorable for survival), differences in OS were noted (P = .002; 25th percentile of OS for low vs intermediate vs high risk, 22 months vs 10 months vs 7 months, respectively). Conclusion Baseline multiparametric MRI assessment including volumetric ADC, percentage viable tumor volume, and viable tumor burden can help predict mortality risk among patients with intrahepatic cholangiocarcinoma undergoing transcatheter arterial chemoembolization. © RSNA, 2018 Online supplemental material is available for this article.

Lidocaine as an Induction Agent for Intracranial Aneurysm Surgery: A Case Series.

INTRODUCTION: Induction of anaesthesia and its associated spikes in blood pressure can cause rupture of an aneurysm during intracranial surgery. Lidocaine can reportedly provide hemodynamic stability when applied before endotracheal intubation. Rapid injection of large doses of lidocaine can cause unconsciousness. CASE PRESENTATION: Lidocaine was applied as the sole anaesthetic for induction and maintenance during aneurysm surgery in four patients undergoing intracranial aneurysm surgery. Blood pressure alteration after induction and during surgery, bleeding, brain laxity, intracranial pressure and extubation time were acceptable. CONCLUSIONS: Although propofol remains a standard agent for such types of surgeries, lidocaine proved equally effective and coupled with its low cost, minimal side effects and omission of other hypnotic agents was a plausible induction agent and a maintenance drug in the selected cases.