Perfusion Of Liver Parenchyma Research Articles

Feasibility of 4D perfusion CT imaging for the assessment of liver treatment response following SBRT and sorafenib

ObjectivesTo evaluate the feasibility of 4-dimensional perfusion computed tomography (CT) as an imaging biomarker for patients with hepatocellular carcinoma and metastatic liver disease. Methods and materialsPatients underwent volumetric dynamic contrast-enhanced CT on a 320-slice scanner before and during stereotactic body radiation therapy and sorafenib, and at 1 and 3 months after treatment. Quiet free breathing was used in the CT acquisition and multiple techniques (rigid or deformable registration as well as outlier removal) were applied to account for residual liver motion. Kinetic modeling was performed on a voxel-by-voxel basis in the gross tumor volume and normal liver resulting in 3-dimensional parameter maps of blood perfusion, capillary permeability, blood volume, and mean transit time. Perfusion characteristics in the tumor and adjacent liver were correlated with radiation dose distributions to evaluate dose-response. Paired t tests assessed change in spatial and histogram parameters from baseline to different time points during and after treatment. Technique reproducibility as well as the impact of arterial and portal vein input functions was also investigated using intra- and inter-subject variance and Bland-Altman analysis. ResultsQuantitative perfusion parameters were reproducible (±5.7%; range, 2%-10%) depending on tumor/normal liver type and kinetic parameter. Statistically significant reductions in tumor perfusion were measurable over the course of treatment and as early as 1 week after sorafenib administration (P < .05). Marked liver parenchyma perfusion reduction was seen with a strong dose-response effect (R2 = 0.95) that increased significantly over the course treatment. ConclusionsThe proposed methodology demonstrated feasibility of evaluating spatiotemporal changes in liver tumor perfusion and normal liver function following antiangiogenic therapy and radiation treatment warranting further evaluation of biomarker prognostication.

3:09 PMAbstract No. 140 - Predicting HCC treatment response to Y-90 radioembolization by quantitative perfusion using contrast-enhanced magnetic resonance angiography

PurposeTo predict hepatocellular carcinoma (HCC) treatment response to Y-90 radioembolization (RAE) by quantitatively evaluating target lesion perfusion using contrast-enhanced MR angiography (MRA).MaterialsQuantitative MR perfusion was performed to evaluate 13 HCC target lesions in 10 patients (avg 67 yrs, 6 men), before and immediately (1hr) after Y-90 RAE. The peak slopes of the signal intensity curves were recorded to determine perfusion of target lesions and were normalized to the arterial input function. Target lesion perfusion was further adjusted by subtracting remote liver parenchyma perfusion. Target lesion response to therapy was assessed using WHO and EASL criteria on routine MR imaging; responses were defined as complete response (CR), partial response (PR), stable disease (SD), or progressive disease (PD). Two-sample t-tests were performed to compare perfusion between lesions.ResultsFollow-up was available for an average of 6.9 (1-17) months. Target lesions averaged 3.1±1.2 cm, treated with an average dose of 191±118 Gy. Target lesions showing response (CR/PR) at 1 and 3 months were: 6/13 (46%) and 6/10 (60%) using EASL, and 0/13 (0%) and 2/10 (20%) using WHO criteria. EASL was used for subsequent analysis as it provided earlier and granular response detail. Average pre-RAE target lesion perfusion was 0.161, increasing post-RAE to 0.211. When the lesions were stratified into responders (CR/PR) and non-responders (SD/PD), responders had significantly lower pre-RAE perfusion compared to non-responders, both at 1 and 3 months (P<0.05, see table). No significant differences were seen for post-RAE perfusion.ConclusionsTabled 1*P<0.051 Month3 MonthsResponderNon-responderResponderNon-responderPre-RAE0.049*0.258*0.041*0.369*Post-RAE0.0570.3390.0580.453 Open table in a new tab PurposeTo predict hepatocellular carcinoma (HCC) treatment response to Y-90 radioembolization (RAE) by quantitatively evaluating target lesion perfusion using contrast-enhanced MR angiography (MRA). To predict hepatocellular carcinoma (HCC) treatment response to Y-90 radioembolization (RAE) by quantitatively evaluating target lesion perfusion using contrast-enhanced MR angiography (MRA). MaterialsQuantitative MR perfusion was performed to evaluate 13 HCC target lesions in 10 patients (avg 67 yrs, 6 men), before and immediately (1hr) after Y-90 RAE. The peak slopes of the signal intensity curves were recorded to determine perfusion of target lesions and were normalized to the arterial input function. Target lesion perfusion was further adjusted by subtracting remote liver parenchyma perfusion. Target lesion response to therapy was assessed using WHO and EASL criteria on routine MR imaging; responses were defined as complete response (CR), partial response (PR), stable disease (SD), or progressive disease (PD). Two-sample t-tests were performed to compare perfusion between lesions. Quantitative MR perfusion was performed to evaluate 13 HCC target lesions in 10 patients (avg 67 yrs, 6 men), before and immediately (1hr) after Y-90 RAE. The peak slopes of the signal intensity curves were recorded to determine perfusion of target lesions and were normalized to the arterial input function. Target lesion perfusion was further adjusted by subtracting remote liver parenchyma perfusion. Target lesion response to therapy was assessed using WHO and EASL criteria on routine MR imaging; responses were defined as complete response (CR), partial response (PR), stable disease (SD), or progressive disease (PD). Two-sample t-tests were performed to compare perfusion between lesions. ResultsFollow-up was available for an average of 6.9 (1-17) months. Target lesions averaged 3.1±1.2 cm, treated with an average dose of 191±118 Gy. Target lesions showing response (CR/PR) at 1 and 3 months were: 6/13 (46%) and 6/10 (60%) using EASL, and 0/13 (0%) and 2/10 (20%) using WHO criteria. EASL was used for subsequent analysis as it provided earlier and granular response detail. Average pre-RAE target lesion perfusion was 0.161, increasing post-RAE to 0.211. When the lesions were stratified into responders (CR/PR) and non-responders (SD/PD), responders had significantly lower pre-RAE perfusion compared to non-responders, both at 1 and 3 months (P<0.05, see table). No significant differences were seen for post-RAE perfusion. Follow-up was available for an average of 6.9 (1-17) months. Target lesions averaged 3.1±1.2 cm, treated with an average dose of 191±118 Gy. Target lesions showing response (CR/PR) at 1 and 3 months were: 6/13 (46%) and 6/10 (60%) using EASL, and 0/13 (0%) and 2/10 (20%) using WHO criteria. EASL was used for subsequent analysis as it provided earlier and granular response detail. Average pre-RAE target lesion perfusion was 0.161, increasing post-RAE to 0.211. When the lesions were stratified into responders (CR/PR) and non-responders (SD/PD), responders had significantly lower pre-RAE perfusion compared to non-responders, both at 1 and 3 months (P<0.05, see table). No significant differences were seen for post-RAE perfusion. ConclusionsTabled 1*P<0.051 Month3 MonthsResponderNon-responderResponderNon-responderPre-RAE0.049*0.258*0.041*0.369*Post-RAE0.0570.3390.0580.453 Open table in a new tab

Hepatic Perfusion Parameters of Contrast-Enhanced Ultrasonography Correlate With the Severity of Chronic Liver Disease

In the study described here, we introduced a new ratio acquired with contrast-enhanced ultrasonography (CEUS): a liver parenchyma blood supply ratio that differentiates arterial and portal phases. Our purpose was to determine whether this ratio and other liver parenchyma perfusion parameters acquired with CEUS can be correlated with the severity of chronic liver disease. Twelve patients with non-cirrhotic chronic liver disease, 35 patients with cirrhosis (child class A: n = 10; child class B: n = 13; child class C: n = 12) and 21 healthy volunteers were examined by CEUS. Time–intensity curves were drawn for regions of interest located in liver parenchyma and right kidney cortex using QLAB quantification software. The arterial and portal phases were differentiated by the time to the maximum enhancement of right kidney and liver parenchyma perfusion data acquired from the time–intensity curves: the intensity of liver parenchyma perfused by hepatic arterial flow (Iap), the intensity of total perfusion of liver parenchyma (Ipeak), the intensity of liver parenchyma perfused by portal venous flow (Ipp) and the ratio of portal perfusion to total perfusion of liver parenchyma expressed by the parameters Ipp/Ipeak, Ipeak, Ipp and Ipp/Ipeak significantly decreased in patients with cirrhosis and in patients with non-cirrhotic chronic liver disease, whereas Iap increased. The parameters Ipp, Ipeak, Ipp/Ipeak and Iap correlated with the severity of chronic liver disease (r = −0.938, p < 0.001; r = −0.790, p < 0.001; r = −0.931 p < 0.001; r = 0.31, p < 0.05). The diagnostic accuracy rates for cirrhosis expressed as areas under receiver operating characteristic curves were 0.93 for Ipeak, 0.98 for Ipp, 0.98 for Ipp/Ipeak, and 0.69 for Iap. Liver parenchyma perfusion parameters obtained by CEUS were correlated with the severity of chronic liver disease and have the potential to assess cirrhosis non-invasively.

Prediction and Reduction of Motion Artifacts in Free-Breathing Dynamic Contrast Enhanced CT Perfusion Imaging of Primary and Metastatic Intrahepatic Tumors

To develop and evaluate a method for predicting and reducing motion artifacts in free-breathing liver perfusion computed tomography (CT) scanning with couch shuttling and to compare tumor and liver parenchyma perfusion values. Thirty patients (23 males, 7 females, median age of 74 years) with primary or metastatic intrahepatic tumors underwent dynamic contrast enhanced CT scans with axial shuttling. A semiautomatic respiratory motion correction algorithm was applied to align the acquired images along the z-axis. Perfusion maps were generated using the dual-input Johnson-Wilson model. Root mean squared deviation (RMSD) maps of the model fit to the pixel time-density curves were calculated. Precorrection RMSD correlated positively with magnitude of change in functional values resulting from motion. Blood flow, arterial blood flow, and permeability surface product were significantly increased in tumor compared to normal tissue (P < .05), blood volume was significantly reduced in tumor compared to normal tissue (P < .05). In a subgroup of patients with high-amplitude motion significant difference was observed between uncorrected and motion correction blood flow maps. Patients can breathe freely during hepatic perfusion imaging if retrospective motion correction is applied to reduce motion artifacts. RMSD provides a regional assessment of motion induced artifacts in liver perfusion maps.

Performance assessment of an opto-fluidic phantom mimicking porcine liver parenchyma

An implantable, optical oxygenation and perfusion sensor to monitor liver transplants during the two-week period following the transplant procedure is currently being developed. In order to minimize the number of animal experiments required for this research, a phantom that mimics the optical, anatomical, and physiologic flow properties of liver parenchyma is being developed as well. In this work, the suitability of this phantom for liver parenchyma perfusion research was evaluated by direct comparison of phantom perfusion data with data collected from in vivo porcine studies, both using the same prototype perfusion sensor. In vitro perfusion and occlusion experiments were performed on a single-layer and on a three-layer phantom perfused with a dye solution possessing the absorption properties of oxygenated hemoglobin. While both phantoms exhibited response patterns similar to the liver parenchyma, the signal measured from the multilayer phantom was three times higher than the single layer phantom and approximately 21 percent more sensitive to in vitro changes in perfusion. Although the multilayer phantom replicated the in vivo flow patterns more closely, the data suggests that both phantoms can be used in vitro to facilitate sensor design.

Evaluation of hepatic perfusion of cirrhosis by contrast-enhanced ultrasonography

Objective To evaluate hepatic perfusion assessed by contrast-enhanced ultrasonography (CEUS) for predicting cirrhosis accurately and non-invasively.Methods Forty patients with cirrhosis and twenty-five healthy controls were given CEUS examination,and time-intensity curves were drawn as the regions of interest located in liver parenchyma by using QLAB analyzing soft.The parameters of the two groups as follows:intensity of arterial perfusion (Iap),intensity of total perfusion of liver parenchyma (Ipeak),intensity of portal venous perfusion (Ipp),the ratio of portal venous perfusion and total perfusion (Ipp/Ipeak) were compared by independent-samples t test,and the diagnostic value of parameters were analyzed by receiver operating characteristic (ROC) curve.Resnlts Iap was bigger,while Ipp,Ipp/Ipeak were smaller in patients than that in controls( P ＜0.001 ).But there was no significant difference on Ipeak between the two groups.When Iap,Ipp,Ipp/Ipeak were used for the diagnosis of cirrhosis,the sensitivity were 67.3 ％,92.7％,96.4％ and the specificity were 80.0％,96.0％,92.3％,respectively.Conclusions CEUS can reflect the changes of the blood perfusion of cirrhotic liver.CEUS parameters Iap,Ipp,Ipp/Ipeak are significant different between the two groups and can be the non-invasive diagosis parameters of cirrhosis. Key words: Ultrasonography; Microbubbles; Liver cirrhosis

Noninvasive evaluation of hepatic fibrosis stages by contrast enhanced ultrasonography parameters

Objective To discuss the feasibility of non-invasive quantitative evaluation of hepatic fibrosis by contrast-enhanced ultrasonography (CEUS) parameters. Methods CEUS of liver and liver biopsy were performed in 86 patients. CEUS parameters including area under curve of portal vein/hepatic artery(Qp/Qa) ,perfusion intensity of portal vein/hepatic artery(Ip/Ia), decreasing rate of liver parenchyma perfusion (β) and perfusion time of portal vein (Tp) were calculated based on CEUS images. Differences of the four parameters among stages of hepatic fibrosis were analyzed by ANOVA and Spearman rank correlation test was applied to analyze correlation between parameters and hepatic fibrosis stages. Areas under receiver operating characteristic (ROC) curves were calculated to evaluate the diagnostic accuracy of parameters. Results Tp and β had increasing tend while Ip/Ia and Qp/Qa had declining tend from S0 to S4.They were significantly correlated with fibrosis stage( P ＜0.05＝. The areas under ROC curves of Ip/Ia were 0.931 (≥S1) ,0.884(≥S2 ) ,0.820(≥S3 ) and 0.846(S4 ) respectively. The areas under ROC curves of Qp/Qa were 0.914(≥S1),0.813(≥S2),0.845(≥S3) and0.869 (S4) respectively. Conclusions CEUS parameters of liver parenchyma Ip/la, Qp/Qa, Tp and β are related to fibrosis stages. Ip/Ia and Qp/Qa provide a reliable,non-invasive method for evaluating fibrosis stages. Key words: Ultrasonography; Microbubbles; Liver cirrhosis

Perfusion CT in cirrhotic patients with early stage hepatocellular carcinoma: Assessment of tumor-related vascularization

Purpose To assess the value of CT-perfusion in determining the quantitative vascularization features of early hepatocellular carcinoma (HCC) in cirrhotic patients. Materials and methods A total of 35 cirrhotic patients with single histologically proven HCC not exceeding 3 cm in diameter underwent conventional triple-phase multidetector computed tomography (MDCT) examination. All patients were also examined with CT-perfusion (CTp) technique after i.v. injection of 50 mL of iodinated contrast. Data were analyzed using a dedicated software which generated a quantitative map of liver parenchyma perfusion. The following parameters were assessed: hepatic perfusion (HP); blood volume (BV); arterial perfusion (AP); time to peak (TTP) and hepatic perfusion index (HPI). Univariate Wilcoxon signed rank test was used for statistical analysis. Results In the 35 HCCs evaluated, the following quantitative data were obtained: HP (mL/s/100 g): median = 47.0 (1 stqt = 35.5; 3 stqt = 61.2); BV (mL/100 mg): median = 22.5 (1 stqt = 18.4; 3 stqt = 27.7); AP (mL/min): median = 42.9 (1 stqt = 35.8; 3 stqt = 55.6); HPI(%): median = 75.3 (1 stqt = 63.1; 3 stqt = 100); TTP(s): median = 18.7 (1 stqt = 16.8; 3 stqt = 24.5). Perfusion values calculated in cirrhotic liver parenchyma were HP: median = 10.3 (1 stqt = 9.1; 3 stqt = 13.2); BV: median = 11.7 (1 stqt = 9.6; 3 stqt = 15.5); AP: median = 10.4 (1 stqt = 8.6; 3 stqt = 11.3); HPI: median = 17.5 (1 stqt = 14.3; 3 stqt = 19.7); TTP: median = 44.6 (1 stqt = 40.3; 3 stqt = 50.1). HP, BV, HPI and AP were found to be significantly higher in HCC lesion than in liver parenchyma ( p < 0.001), while TTP was significantly lower ( p < 0.001). Conclusion CT-perfusion technique allows obtaining quantitative information about tumor-related vascularization of early HCC, in patients with liver cirrhosis.

Diffuse Leberparenchymerkrankungen: Wertigkeit der KST im Vergleich mit Sonographie und CT

29 patients with diffuse liver disease were examined by ultrasound, CT and MRI. MRI imaging was performed using T1-and t2-weighted spin-echo-sequences and fast gradient-echo-sequences. The paramagnetic contrast agent Gd-DTPA was applied intravenously (0.1 mmol/kg). In all patients with hepatitis MRI enabled exact liver biopsy by delineation of inflammatory changes in cases of chronic or focal hepatitis. CT and ultrasound were superior to MRI in the detection of focal or diffuse fatty degeneration. However, MRI enabled an exact differentiation of fatty changes from neoplasm. In cases of fibrotic changes the most accurate findings could be shown by MRI. In patients suffering from hemochromatosis MRI supplied additional information compared to CT and ultrasound revealing significant reduction of signal intensity due to reinforced enhancement of iron. Concerning Wilson's disease MRI showed a characteristic pattern of parenchymal changes. The application of Gd-DTPA in cases of diffuse liver disease adds supplementary information about perfusion of liver parenchyma, but its value for diagnostic accuracy is only secondary.