Dynamic Liver Magnetic Resonance Imaging Research Articles

Dynamic Liver Magnetic Resonance Imaging During Free Breathing: A Feasibility Study With a Motion Compensated Variable Density Radial Acquisition and a Viewsharing High-Pass Filtering Reconstruction.

Robust dynamic contrast-enhanced T1-weighted images are crucial for accurate detection and categorization of focal liver lesions in liver/abdominal magnetic resonance imaging (MRI). As optimal dynamic imaging usually requires multiple breath-holds, its inherent susceptibility to motion artifacts frequently results in degraded image quality in incompliant patients. Because free-breathing imaging may overcome this drawback, the intention of this study was to evaluate a dynamic MRI sequence acquired during free breathing using the variable density, elliptical centric golden angle radial stack-of-stars radial sampling scheme, which so far has not been implemented in 4-dimensional applications. In a prospective pilot study, 27 patients received a routine abdominal MRI protocol including the prototype free-breathing sequence (4DFreeBreathing) for dynamic imaging. This enables more convenient and faster reconstruction through variable density, elliptical centric golden angle radial stack-of-stars without the use of additional reconstruction hardware, and even higher motion robustness through soft-gating. A standard breath-hold sequence performed subsequently served as reference standard. Of the continuous dynamic data sets, each dynamic phase was analyzed regarding image quality, motion artifacts and vessel conspicuity using 5-point Likert scales. Furthermore, correct timing of the late arterial phase was compared with the preexaminations. 4DFreeBreathing delivered motion-free dynamic images with high temporal resolution in each subject. Overall image quality scores were rated good or excellent for 4DFreeBreathing and the gold standard without significant differences (P = 0.34). There were significantly less motion artifacts in the 4DFreeBreathing sequence (P < 0.0001), whereas vessel conspicuity in each dynamic phase was comparable for both groups (P = 0.45, P > 0.99, P = 0.22, respectively). Correct timing of the late arterial phase could be achieved in 27 of 27 (100%) examinations using 4DFreeBreathing versus 35 of 53 (66%) preexaminations using gold standard (P < 0.001). The benefit of convenient and fast image reconstruction combined with the superiority in motion robustness and timing compared with standard breath hold sequences renders 4DFreeBreathing an attractive alternative to existing free-breathing techniques in dynamic liver MRI.

Intraindividual Comparison of Compressed Sensing-Accelerated Cartesian and Radial Arterial Phase Imaging of the Liver in an Experimental Tumor Model.

The aim of this study was to intraindividually compare the performance of 2 compressed sensing (CS)-accelerated magnetic resonance imaging (MRI) sequences, 1 featuring Cartesian (compressed sensing volumetric interpolated breath-hold examination [CS-VIBE]) and the other radial (golden-angle radial sparse parallel [GRASP]) k-space sampling in continuous dynamic imaging during hepatic vascular phases, using extracellular and hepatocyte-specific contrast agents. Seven New Zealand white rabbits, with induced VX2 liver tumors (median number of lesions, 2 ± 0.83; range, 1-3), received 2 continuously acquired T1-weighted prototype CS-accelerated MRI sequences (CS-VIBE and GRASP) with high spatial (0.8 × 0.8 × 1.5 mm) and temporal resolution (3.5 seconds) in randomized order on 2 separate days using a 1.5-T scanner. In all animals, imaging was performed using first gadobutrol at a dose of 0.1 mmol/kg and, then 45 minutes later, gadoxetic acid at a dose of 0.025 mmol/kg.The following qualitative parameters were assessed using 3- and 5-point Likert scales (3 and 5 being the highest scores respectively): image quality (IQ), arterial and venous vessel delineation, tumor enhancement, motion artifacts, and sequence-specific artifacts. Furthermore, the following quantitative parameters were obtained: relative peak signal enhancement, time to peak, mean transit time, and plasma flow ratios. Paired sampled t tests and Wilcoxon signed rank tests were used for intraindividual comparison. Image analysis was performed by 2 radiologists. Six of 7 animals underwent the full imaging protocol and obtained data were analyzed statistically. Overall IQ was rated moderate to excellent, not differing significantly between the 2 sequences.Gadobutrol-enhanced CS-VIBE examinations revealed the highest mean Likert scale values in terms of vessel delineation and tumor enhancement (arterial 4.4 [4-5], venous 4.3 [3-5], and tumor 2.9 [2-3]). Significantly, more sequence-specific artifacts were seen in GRASP examinations (P = 0.008-0.031). However, these artifacts did not impair IQ. Excellent Likert scale ratings were found for motion artifacts in both sequences. In both sequences, a maximum of 4 hepatic arterial dominant phases were obtained. Regarding the relative peak signal enhancement, CS-VIBE and GRASP showed similar results. The relative peak signal enhancement values did not differ significantly between the 2 sequences in the aorta, the hepatic artery, or the inferior vena cava (P = 0.063-0.536). However, significantly higher values were noted for CS-VIBE in gadoxetic acid-enhanced examinations in the portal vein (P = 0.031) and regarding the tumor enhancement (P = 0.005). Time to peak and mean transit time or plasma flow ratios did not differ significantly between the sequences. Both CS-VIBE and GRASP provide excellent results in dynamic liver MRI using extracellular and hepatocyte-specific contrast agents, in terms of IQ, peak signal intensity, and presence of artifacts.

Respiratory motion in children and young adults undergoing liver magnetic resonance imaging with intravenous gadoxetate disodium contrast material

Gadoxetate disodium, utilized in hepatobiliary magnetic resonance (MR) imaging, has been associated with transient respiratory motion during the arterial phase in adults. The purpose of this study was to determine the presence and severity of this phenomenon in children imaged awake versus under general anesthesia. This retrospective cohort study was approved by the institutional review board; informed consent was waived. One hundred thirty exams of children ≤18years old who underwent dynamic liver MR imaging with gadoxetate disodium between October 2010 and January 2018 were reviewed. Three pediatric radiologists scored respiratory motion artifacts on all imaging phases using a 5-point Likert scale. Differences in mean motion scores were assessed with analysis of variance and Tukey's multiple comparisons test, and multivariable regression was used to identify predictors of arterial phase motion in awake patients. One hundred thirty patients (50% [n=65] female; mean age: 9.8±3.7years, 48.5% [n=63] awake) were included. There were significant differences in mean motion scores between phases in the awake cohort (P<0.0001) but not in the general anesthesia cohort (P=0.051). In the awake cohort, arterial phase motion score (mean: 3.52±0.83) was significantly higher than mean motion score in all other phases (P≤0.0003). There were no significant patient-specific predictors of arterial phase motion score in the awake cohort. Significantly increased arterial phase respiratory motion artifact in awake children undergoing dynamic liver MR imaging with gadoxetate disodium suggests that transient respiratory motion occurs in children. General anesthesia may suppress this phenomenon.

Compressed Sensing and Parallel Imaging for Double Hepatic Arterial Phase Acquisition in Gadoxetate-Enhanced Dynamic Liver Magnetic Resonance Imaging.

The aim of this study was to investigate the utility of a combined compressed sensing and parallel imaging (C-SENSE) technique for single breath-hold, double arterial phase (AP) examinations in gadoxetate-enhanced magnetic resonance imaging (MRI) of the liver. We retrospectively reviewed single breath-hold, double AP images obtained by using a C-SENSE technique for gadoxetate-enhanced dynamic liver MRI in a total of 127 patients (89 men and 38 women; mean age, 62.6 ± 7.5 [range, 29-87] years). For qualitative analysis, 3 readers independently scored the timing of the AP images, degree of artifacts, and overall image quality on both the first and second AP images (AP1 and AP2, respectively). The combined scores of AP1 and AP2 (AP1 + AP2) were determined by using the better scores from the 2 sets. Focal lesion detectability was assessed for 124 lesions with arterial enhancement on AP1 and AP2, and on simultaneous review of both AP1 and AP2. Then, in 62 patients whose previous gadoxetate-enhanced single AP images were available, AP timing and overall image quality were compared between single and double AP images. Wilcoxon signed rank test was performed for each comparison. Fleiss kappa value was calculated for analysis of interreader agreement. Optimal AP timing was achieved in 86% of AP1, 65% of AP2, and 90% of AP1 + AP2 images; results were significantly better for AP1 and AP1 + AP2 images than for AP2 images (P < 0.001 for both comparisons). Respiratory motion artifacts were negligible in 73% of the AP1 + AP2 images, which was significantly better than the corresponding values for the AP1 (61%, P < 0.001) or AP2 (50%, P < 0.001) images. Overall image quality was significantly better for AP1 + AP2 (excellent in 54%) than for AP1 (49%, P < 0.001) or AP2 (39%, P < 0.001) images. Lesion detectability was comparable between AP1 and AP2 images and was significantly better on AP1 + AP2. Comparison of single and double AP imaging techniques showed better AP timing (P = 0.004) and fewer respiratory motion artifacts (P < 0.001) for AP1 + AP2 than for the single AP images. The C-SENSE technique may facilitate single breath-hold, double AP imaging with optimal timing and reduced respiratory motion artifacts in gadoxetate-enhanced dynamic MRI of the liver.

Intra-individual comparison of gadolinium-enhanced MRI using pseudo-golden-angle radial acquisition with gadoxetic acid-enhanced MRI for diagnosis of HCCs using LI-RADS.

To determine the usefulness of extracellular contrast agent (ECA)-enhanced multiphasic liver magnetic resonance imaging (MRI) using a pseudo-golden-angle radial acquisition scheme by intra-individual comparison with gadoxetic acid-MRI (EOB-MRI) with regard to image quality and the diagnosis of hepatocellular carcinoma (HCC). This prospective study enrolled 15 patients with 18 HCCs who underwent EOB-MRI using a Cartesian approach and ECA-MRI using the pseudo-golden-angle radial acquisition scheme (free-breathing continuous data acquisition for 64s following ECA injection, generating six images). Two reviewers evaluated the arterial and portal phases of each MRI for artifacts, organ sharpness, and conspicuity of intrahepatic vessels and the hepatic tumors. A Liver Imaging Reporting and Data System category was also assigned to each lesion. There were no differences in the subjective image quality analysis between the arterial phases of two MRIs (p > 0.05). However, ghosting artifact was seen only in EOB-MRI (N = 3). Six HCCs showed different signal intensities in the arterial phase or portal phase between the two MRIs; five HCCs showed arterial hyperenhancement on ECA-MRI, but not on EOB-MRI. The capsule was observed in 15 HCCs on ECA-MRI and 6 HCCs on EOB-MRI. Five and one HCC were assigned as LR-5 and LR-4 with ECA-MRI and LR-4 and LR-3 with EOB-MRI, respectively. Free-breathing ECA-enhanced multiphasic liver MRI using a pseudo-golden-angle radial acquisition was more sensitive in detecting arterial hyperenhancement of HCC than conventional EOB-MRI, and the image quality was acceptable. • The pseudo-golden-angle radial acquisition scheme can be applied to perform free-breathing multiphasic dynamic liver MRI. • Adopting the pseudo-golden-angle radial acquisition scheme can improve the detection of arterial enhancement of HCC. • The pseudo-golden-angle radial acquisition scheme enables motion-free liver MRI.

Experimental studies on artifacts and tumor enhancement on gadoxetic acid-enhanced arterial phase liver MRI in a rabbit VX2 tumor model.

Background Rapid injection of gadoxetic acid is reported to produce more frequent artifacts and lower vascular enhancement on arterial phase liver magnetic resonance imaging (MRI). However, its effect on tumor enhancement and the mechanism of the artifacts remain unclear. Purpose To evaluate the effect of rapid injection of gadoxetic acid on artifacts and tumor enhancement during arterial phase liver MRI, and on arterial blood gases (ABGs) which may explain the cause of the artifacts. Material and Methods ABG analysis was performed in 13 free-breathing rabbits after rapid injection (1 mL/s; injection time = 0.6-0.8 s) of gadoxetic acid (0.025 mmol/kg). Dynamic liver MRI was performed in six anesthetized rabbits with VX2 tumors under a ventilation stoppage after rapid and slow injection (0.25 mL/s; injection time = 2.4-3.2 s) of gadoxetic acid. Artifacts and signal enhancement on arterial phase imaging were compared with those obtained after rapid injection of gadopentetic acid (Gd-DTPA, 0.1 mmol/kg) using a Friedman test or Kruskal-Wallis test. Results ABG analysis did not find any significant changes. Artifacts were not related to injection protocols ( P = 0.95). Aortic enhancement with slow injection of gadoxetic acid was significantly higher than that with rapid injection ( P < 0.05), and was comparable to that with Gd-DTPA injection. Tumor enhancement obtained with gadoxetic acid was not significantly different between rapid and slow injection, and was significantly lower than that with Gd-DTPA injection ( P < 0.05). Conclusion Rapid injection of gadoxetic acid did not affect ABGs and may not be the cause of the artifacts. It lowered vascular enhancement but not arterial tumor enhancement.

Dynamic Liver Magnetic Resonance Imaging in Free-Breathing: Feasibility of a Cartesian T1-Weighted Acquisition Technique With Compressed Sensing and Additional Self-Navigation Signal for Hard-Gated and Motion-Resolved Reconstruction.

The aim of this study was to assess the feasibility of a free-breathing dynamic liver imaging technique using a prototype Cartesian T1-weighted volumetric interpolated breathhold examination (VIBE) sequence with compressed sensing and simultaneous acquisition of a navigation signal for hard-gated and motion state-resolved reconstruction. A total of 43 consecutive oncologic patients (mean age, 66 ± 11 years; 44% female) underwent free-breathing dynamic liver imaging for the evaluation of liver metastases from colorectal cancer using a prototype Cartesian VIBE sequence (field of view, 380 × 345 mm; image matrix, 320 × 218; echo time/repetition time, 1.8/3.76 milliseconds; flip angle, 10 degrees; slice thickness, 3.0 mm; acquisition time, 188 seconds) with continuous data sampling and additionally acquired self-navigation signal. Data were iteratively reconstructed using 2 different approaches: first, a hard-gated reconstruction only using data associated to the dominating motion state (CS VIBE, Compressed Sensing VIBE), and second, a motion-resolved reconstruction with 6 different motion states as additional image dimension (XD VIBE, eXtended dimension VIBE). Continuous acquired data were grouped in 16 subsequent time increments with 11.57 seconds each to resolve arterial and venous contrast phases. For image quality assessment, both CS VIBE and XD VIBE were compared with the patient's last staging dynamic liver magnetic resonance imaging including a breathhold (BH) VIBE as reference standard 4.5 ± 1.2 months before. Representative quality parameters including respiratory artifacts were evaluated for arterial and venous phase images independently, retrospectively and blindly by 3 experienced radiologists, with higher scores indicating better examination quality. To assess diagnostic accuracy, same readers evaluated the presence of metastatic lesions for XD VIBE and CS VIBE compared with reference BH examination in a second session. Compared with CS VIBE, XD VIBE showed significantly higher overall image quality for both arterial phase (4.2 ± 0.6 vs 3.8 ± 0.7, P = 0.008) and venous phase (4.7 ± 0.4 vs 4.3 ± 0.7, P < 0.001) imaging. There was no significant difference between XD VIBE and BH VIBE for overall image quality in the venous phase (4.7 ± 0.4 vs 4.8 ± 0.4, P = 0.834), whereas arterial phase images were scored slightly lower for XD VIBE (4.5 ± 0.6 vs 4.2 ± 0.6, P = 0.024). Both XD VIBE and BH VIBE were characterized by a very low level of respiratory artifacts with no significant difference between BH and motion-resolved free-breathing strategy (P = 0.505 for arterial phase; P = 0.496 for venous phase). Compared with CS VIBE, obvious quality improvement could be achieved for the extended XD VIBE reconstruction with significantly reduced motion artifacts for venous phase images (P = 0.007). Generally, arterial phase images were scored slightly lower compared with venous phase images when using the free-breathing protocol. Overall, 98% of all metastatic lesions were identified on XD VIBE images and 92% of all metastases were found on CS VIBE. Dynamic liver imaging using the proposed free-breathing Cartesian strategy is feasible in oncologic patients with excellent image quality, high respiratory motion robustness, and accurate lesion detection. Overall, XD VIBE was superior to CS VIBE in our study.

Imaging findings of primary hepatic angiosarcoma on gadoxetate disodium-enhanced liver MRI: comparison with hepatic haemangiomas of similar size

To describe imaging characteristics of primary hepatic angiosarcoma on gadoxetate disodium-enhanced dynamic magnetic resonance imaging (MRI) and to determine features that differentiate angiosarcomas from similar-sized haemangiomas. The study included 15 patients with hepatic angiosarcomas and 35 patients with size-matched hepatic haemangiomas who underwent gadoxetate disodium-enhanced liver MRI. The number, size, growth pattern, signal intensity (SI) characteristics, and SI changes on dynamic scans were evaluated and compared between the two entities. Overall, hepatic angiosarcomas significantly more often showed lesion multiplicity (86.7%), capsular retraction (40%), prominent intratumoural vessels (66.7%), vascular invasion (20%), heterogeneous SI on T2-weighted (100%) and hepatobiliary phase images (80%), and intralesional haemorrhage (60%, all p<0.05). On dynamic scans, angiosarcomas demonstrated enhancing foci of irregular or rim-like nodular/linear or bizarre (86.7%) shapes, with centrifugal or bizarre patterns of progressive enhancement (53.3%). Enhancement of angiosarcomas was less than that of the blood pool on visual grading, but the enhancement curves followed that of the aorta. Regardless of size, angiosarcomas showed heterogeneous T2 SI, intratumoural haemorrhage, and heterogeneity during the hepatobiliary phase, whereas these findings were more common in haemangiomas >6 cm in diameter. Gadoxetate disodium-enhanced dynamic liver MRI is capable of depicting vascular hallmarks of hepatic angiosarcomas. Heterogeneous SI on T2-weighted and hepatobiliary phase images, multiplicity, and an enhancement curve following that of the aorta are also distinctive features that differentiate angiosarcomas from haemangiomas.

Primary hepatic neuroendocrine tumor: A case report and literature review

Primary hepatic neuroendocrine tumors (PHNETs) are extremely rare and difficult to distinguish from other liver tumors, such as hepatocellular carcinoma (HCC) and cholangiocarcinoma, based on medical imaging findings. A 70-year-old man was referred for evaluation of liver mass incidentally discovered on abdominal computed tomography. The characteristic finding from dynamic liver magnetic resonance imaging led to a diagnosis of HCC. The patient underwent right hepatectomy. Histopathological and immunohistochemical examination revealed grade 2 neuroendocrine tumor. The postoperative 24-h urinary excretion of 5-hydroxy-indolacetic acid was within the normal range. Further imaging investigations were performed. No other lesions were found making probable the diagnosis of PHNET. This case shows that the diagnosis of PHNET is a medical challenge, requiring differentiation of PHNETs other hepatic masses and exclusion of occult primary neuroendocrine tumors. The diagnosis of PHNET can be ascertained after long term follow-up to exclude another primary origin.

Respiratory Motion-Resolved Compressed Sensing Reconstruction of Free-Breathing Radial Acquisition for Dynamic Liver Magnetic Resonance Imaging.

This study aimed to demonstrate feasibility of free-breathing radial acquisition with respiratory motion-resolved compressed sensing reconstruction [extra-dimensional golden-angle radial sparse parallel imaging (XD-GRASP)] for multiphase dynamic gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced liver imaging, and to compare image quality to compressed sensing reconstruction with respiratory motion-averaging (GRASP) and prior conventional breath-held Cartesian-sampled data sets [BH volume interpolated breath-hold examination (VIBE)] in same patients. In this Health Insurance Portability and Accountability Act-compliant prospective study, 16 subjects underwent free-breathing continuous radial acquisition during Gd-EOB-DTPA injection and had prior BH-VIBE available. Acquired data were reconstructed using motion-averaging GRASP approach in which consecutive 84 spokes were grouped in each contrast-enhanced phase for a temporal resolution of approximately 14 seconds. Additionally, respiratory motion-resolved reconstruction was performed from the same k-space data by sorting each contrast-enhanced phase into multiple respiratory motion states using compressed sensing algorithm named XD-GRASP, which exploits sparsity along both the contrast-enhancement and respiratory-state dimensions.Contrast-enhanced dynamic multiphase XD-GRASP, GRASP, and BH-VIBE images were anonymized, pooled together in a random order, and presented to 2 board-certified radiologists for independent evaluation of image quality, with higher score indicating more optimal examination. The XD-GRASP reconstructions had significantly (all P < 0.05) higher overall image quality scores compared to GRASP for early arterial (reader 1: 4.3 ± 0.6 vs 3.31 ± 0.6; reader 2: 3.81 ± 0.8 vs 3.38 ± 0.9) and late arterial (reader 1: 4.5 ± 0.6 vs 3.63 ± 0.6; reader 2: 3.56 ± 0.5 vs 2.88 ± 0.7) phases of enhancement for both readers. The XD-GRASP also had higher overall image quality score in portal venous phase, which was significant for reader 1 (4.44 ± 0.5 vs 3.75 ± 0.8; P = 0.002). In addition, the XD-GRASP had higher overall image quality score compared to BH-VIBE for early (reader 1: 4.3 ± 0.6 vs 3.88 ± 0.6; reader 2: 3.81 ± 0.8 vs 3.50 ± 1.0) and late (reader 1: 4.5 ± 0.6 vs 3.44 ± 0.6; reader 2: 3.56 ± 0.5 vs 2.94 ± 0.9) arterial phases. Free-breathing motion-resolved XD-GRASP reconstructions provide diagnostic high-quality multiphase images in patients undergoing Gd-EOB-DTPA-enhanced liver examination.

Hepatic Arterial Phase on Gadoxetic Acid-Enhanced Liver MR Imaging: A Randomized Comparison of 0.5 mL/s and 1 mL/s Injection Rates

ObjectiveTo compare gadoxetic acid injection rates of 0.5 mL/s and 1 mL/s for hepatic arterial-phase magnetic resonance (MR) imaging.Materials and MethodsIn this prospective study, 101 consecutive patients with suspected focal liver lesions were included and randomly divided into two groups. Each group underwent dynamic liver MR imaging using a 3.0-T scanner after an intravenous injection of gadoxetic acid at rates of either 0.5 mL/s (n = 50) or 1 mL/s (n = 51). Arterial phase images were analyzed after blinding the injection rates. The signal-to-noise ratios (SNRs) of the liver, aorta, portal vein, hepatic vein, spleen, and pancreas were measured. The contrast-to-noise ratios (CNRs) of the hepatocellular carcinomas (HCC) were calculated. Finally, two experienced radiologists were independently asked to identify, if any, HCCs in the liver on the images and score the image quality in terms of the presence of artifacts and the proper enhancement of the liver, aorta, portal vein, hepatic vein, hepatic artery, spleen, pancreas, and kidney.ResultsThe SNRs were not significantly different between the groups (p = 0.233-0.965). The CNRs of the HCCs were not significantly different (p = 0.597). The sensitivity for HCC detection and the image quality scores were not significantly different between the two injection rates (p = 0.082-1.000).ConclusionImage quality and sensitivity for hepatic HCCs of arterial-phase gadoxetic acid-enhanced MR were not significantly improved by reducing the contrast injection rate to 0.5 mL/s compared with 1 mL/s.

MRECIST and EASL responses at early time point by contrast-enhanced dynamic MRI predict survival in patients with unresectable hepatocellular carcinoma (HCC) treated by doxorubicin drug-eluting beads transarterial chemoembolization (DEB TACE)

BackgroundWe analyzed the magnetic resonance imaging (MRI) responses by world health organization (WHO), response evaluation criteria in solid tumor (RECIST), European Association for the Study of Liver (EASL), and modified RECIST (mRECIST) guidelines and correlated with survival after doxorubicin (Adriamycin; Pharmacia & Upjohn, Peapac, NJ). drug-eluting beads transarterial chemoembolization (DEB TACE) in patients with unresectable hepatocellular carcinoma (HCC). Patients and methodsThe early target and overall imaging responses were studied in 120 consecutive patients treated with DEB TACE for unresectable HCC, using RECIST, WHO, EASL, and mRECIST guidelines on contrast-enhanced dynamic liver MRI. The median period between the DEB TACE and assessment scan was 33.50 days. Survival analyses were carried out with the Kaplan–Meier method and the Cox proportional model. ResultsWHO and RECIST1.1 had poor correlation with survival. mRECIST and EASL had significant correlation with survival with target lesion response rates of 63.3% and 48.3% and with overall response rates of 52.5% and 39.2%, respectively. The responders of EASL and mRECIST had significant median survival (P ≤ 0.0001). Moreover, mRECIST was better than EASL in predicting survival, because the survival difference between responders and non-responders of overall response was statistically significant (P = 0.013) for mRECIST, but not for EASL (P = 0.064). ConclusionsEASL and mRECIST responses measured on MRI at an early time point after DEB TACE predicted survival. mRECIST response demonstrated higher survival correlation than EASL.

Functional residual capacity breath hold for subtraction image of dynamic liver MRI

Purpose In dynamic liver magnetic resonance imaging (MRI) studies, there are problems with misregistration when subtraction images are processed. For reduction of the misregistration, a functional residual capacity (FRC) phase breath-hold (FRC B-H) method was used. Material and methods Sixty patients (32 males and 28 females, aged 33–85 years, median age 69 years) were examined. The subjects were chronologically categorized into two groups: a voluntary expiratory (VE) B-H group and a FRC B-H group. The blood-flow phase images were classified as plain, arterial, portal and parenchymal phases. To evaluate the reproducibility of liver positions between VE B-H and FRC B-H in each phase (between Plain and Arterial, Arterial and Portal, Plain and Parenchymal), the misregistration areas were compared on the top of the liver. Results The misregistration area between Plain–Arterial, Arterial–Portal and Plain–Parenchymal in VE B-H was 731.0 ± 1153.6, 1134.9 ± 1357.2 and 628.4 ± 844.5 (cm 2), respectively. The misregistration area between each phase in FRC B-H was 386.4 ± 874.9, 574.5 ± 1086.1 and 279.8 ± 551.2 (cm 2), respectively. Using the Mann–Whitney U-test as quantitative analysis, the difference in misregistration areas between two groups was statistically significant ( p < 0.05). Differences in the qualitative analysis were also significant according to the χ 2 test ( p < 0.05). Conclusion The liver positions with FRC B-H were markedly more reproducible than those with VE B-H. To improve the registration accuracy of subtraction dynamic liver MRI, the FRC B-H should be used.

Comparison of Gadolinium-BOPTA and Ferucarbotran-Enhanced Three-Dimensional T1-Weighted Dynamic Liver Magnetic Resonance Imaging in the Same Patient

We sought to compare signal changes using Ferucarbotran and gadobenate dimeglumine (Gd-BOPTA) in dynamic 3D T1-weighted (T1w) GRE imaging of the liver. Thirty patients were prospectively included in the study. All patients underwent 2 high-field magnetic resonance (MR) examinations: first with Gd-BOPTA (Gd) and then after a mean interval of 4 days with ferucarbotran (Feru). Dynamic MRI was obtained with a 3D T1w GRE sequence (TR 6.33, TE 2.31, flip angle 20 degrees ). Contrast enhanced scans were assessed before intravenous injection of the contrast agent (precontrast), and postcontrast during the arterial phase (30 seconds), portal venous phase (60 seconds), and equilibrium phase (120 seconds). The signal intensities (SIs) of liver, spleen, aorta, and portal vein were defined by region of interest measurements. Signal intensity changes (SICs) and percentage signal intensity change (PSIC) were calculated using the formulas SIC=(SI pre - SI post)/SI pre and PSIC=SIC x 100%. Positive signal enhancement was observed after intravenous injection of Feru during all dynamic measurements, whereas the mean SI values were lower compared with Gd. During the portal venous phase the mean SI of Gd was up to a factor of 2.1 higher (portal vein). The widest difference of SIC was observed during the equilibrium phase for liver parenchyma (Gd, 1.03; Feru, 0.24). The dynamic signal courses were similar for liver, portal vein and aorta. Different signal courses were obtained for the spleen. Feru-enhanced T1w dynamic images demonstrated significant signal increases for liver, vessels, and spleen but overall lower signal intensities than Gd-BOPTA. The dynamic signal courses of ferucarbotran were similar to that of Gd-BOPTA during ll perfusion phases except in the spleen. Thus, it may be possible to detect typical enhancement pattern of focal liver lesions with Feru-enhanced dynamic T1w MRI.

Three‐dimensional dynamic liver MR imaging using sensitivity encoding for detection of hepatocellular carcinomas: Comparison with superparamagnetic iron oxide‐enhanced MR imaging

To assess the diagnostic performance of three-dimensional dynamic liver imaging with sensitivity encoding (SENSE), including double arterial phase images and increased resolution, by comparing it to superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging for the detection of hypervascular hepatocellular carcinoma (HCC). Twenty-seven consecutive patients with 50 HCCs underwent Gd-BOPTA-enhanced dynamic imaging using SENSE and SPIO-enhanced MR imaging with at least a 24-hour interval between examinations. Using a three-dimensional gradient-echo technique applying SENSE, dynamic imaging consisting of double arterial phase-, portal phase- and delayed phase-images, was obtained. Using T2-weighted turbo spin-echo and T2*-weighted fast imaging with steady-state precession sequence, SPIO-enhanced MR imaging was obtained. For qualitative analysis, the diagnostic accuracy of both MR examinations for detecting the 50 HCCs was evaluated using the alternative free-response receiver operating characteristic method. Sensitivity and positive predictive value were also evaluated. The mean sensitivity and positive predictive value of three-dimensional dynamic imaging with SENSE were 91.3% and 89.2%, respectively, and those of SPIO-enhanced imaging were 77.3% and 92.6 %, respectively. There was a significant difference in sensitivity between the two images (P <0.05). The mean Az value of three-dimensional dynamic imaging with SENSE (0.97 +/- 0.01) was significantly higher than that of SPIO-enhanced imaging (0.90 +/- 0.02) (P=0.00). Three-dimensional dynamic liver MR imaging using SENSE for acquiring double arterial phase images is more efficient than SPIO-enhanced MR imaging for detecting HCCs.

Double Contrast Media enhanced MRI with Ferumoxides-Gadolinium on Hepatocellular Carcinoma

Purpose: To evaluate the effects of Ferumoxides on Gadolinium (Gd) enhanced dynamic liver magnetic resonance imaging (MRI) in cirrhotic patients and also for the diagnosis of hepatocellular carcinoma (HCC). Materials and Methods: 29 patients with liver cirrhosis were examined at 1.5T. 12 patients had HCC. The imaging protocol included GE T1 in and opposed phases, and a breath-hold TSE T2 before and 30- 60 min following 0.05 ml/kg Ferumoxides. Four dynamic in-phase GE series were also acquired after an injection of 20 ml of Gd at 2 ml/sec. SNR and CNR were calculated for liver lesion relative to the muscle and background liver respectively. Statistical analysis was performed using the paired t-test. Results: The SNR of the liver decreased by 8.6±1.20 (p<0.001) after Ferumoxides injection. At the peak of the Gd effect, the liver increased by 6.09±1.15 relative to the post Ferumoxides, but it was not significantly different from the pre-Ferumoxides study (p<0.01). Although there was no significant change in post Ferumoxides SNR of HCC, CNR of HCC relative to the liver increased by 7.54±1.61 (p<0.05). After the Gd injection, CNR of HCC increased by 15.6±3.87 (p<0.05). Conclusion: The administration of Ferumoxides made HCC CNR increase, and it canceled the effect of Gd enhancement of the cirrhotic liver. The combination of Ferumoxides and Gd makes HCC CNR increase.