Assessing liver function in patients with HBV-related HCC: a comparison of T1 mapping on Gd-EOB-DTPA-enhanced MR imaging with DWI.

OBJECTIVES: To compare the potential of T1 mapping on gadoxetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) for assessing liver function in patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). METHODS: One hundred consecutive patients with known HBV-related HCCs were included. T1 relaxation time and apparent diffusion coefficient (ADC) of the liver were measured, and the reduction rate of T1 relaxation time (∆%) was calculated. T1 relaxation time measurements were compared with ADC values according to the Model for End-Stage Liver Disease (MELD) score. RESULTS: Hepatobiliary phase (HBP) and ∆% of T1 relaxation time measurements showed significant correlations with MELD score (rho = 0.571, p < 0.0001; rho = -0.573, p < 0.0001, respectively). HBP and ∆% of T1 relaxation time were significantly different between good (MELD ≤8) and poor liver function (MELD ≥9) (p < 0.0001 for both). Areas under the receiver operating characteristic curves (AUCs) of T1 relaxation time for HBP (AUC 0.84) and ∆% (AUC 0.82) were significantly better than for ADC (AUC 0.53; p < 0.0001). CONCLUSIONS: T1 mapping on Gd-EOB-DTPA-enhanced MRI showed promise for evaluating liver function in patients with HBV-related HCC, while DWI was not reliable. HBP T1 relaxation time measurement was equally accurate as ∆% measurement. KEY POINTS: • T 1 mapping on Gd-EOB-DTPA MRI was accurate for assessing liver function. • HBP T 1 relaxation time measurement was as accurate as ∆% T 1 • T 1 mapping on Gd-EOB-DTPA MRI was more accurate than DWI-ADC measurement.

Usefulness of T1 mapping on Gd-EOB-DTPA-enhanced MR imaging in assessment of non-alcoholic fatty liver disease.

OBJECTIVES: This study evaluates the value of Gd-EOB-DTPA-enhanced MRI for diagnosis and staging of non-alcoholic fatty liver disease (NAFLD) in an animal model by T1 relaxation time measurement. METHODS: Thirty-four rabbits were divided into the control group (n = 10) and NAFLD group, which was split into four groups (n = 6) with a high-fat diet for an interval of 3 weeks. A dual flip angle was performed before and at the hepatobiliary phase (HBP). T1 relaxation times of the liver parenchyma and the decrease rate (∆%) were calculated. Histological findings according to semi-quantitative scoring of steatosis, activity and fibrosis were the standard of reference. RESULTS: HBP and ∆% T1 relaxation time measurement showed significant differences between normal and NAFLD groups, between non-alcoholic steatohepatitis (NASH) and NAFLD without NASH (p = 0.000-0.049), between fibrosis groups (p = 0.000-0.019), but no difference between F1 and F2 (p = 0.834). The areas under the receiver operating characteristic curves (AUCs) of T1 relaxation time for HBP and ∆% were 0.86-0.93 for the selection of NASH and activity score ≥2, and 0.86-0.95 for the selection of F ≥ 1, 2, 3. No significant difference was found for diagnostic performance between HBP and ∆% T1 relaxation time. CONCLUSIONS: HBP T1 relaxation time measurement of Gd-EOB-DTPA-enhanced MRI was useful to evaluate NAFLD according to the SAF score. HBP T1 relaxation time measurement was as accurate as ∆% T1 relaxation time. KEY POINTS: • Gd-EOB-DTPA-enhanced MRI could give useful information on NAFLD. •HBP T 1 relaxation time measurement was useful for the evaluation of NAFLD. • HBP T 1 relaxation time measurement was as accurate as ∆%.

Influence of applying nitroglycerin in whole-heart free-breathing 3D coronary MR angiography.

OBJECTIVE: The purpose of our study was to assess the impact of sublingual nitroglycerin (NTG) spray on free-breathing 3D whole-heart coronary MR angiography (MRA). SUBJECTS AND METHODS: We compared the timing parameters; measured the lumen diameter of the major coronary arteries; calculated coronary vasodilation, apparent signal-to-noise ratio (SNR), and apparent contrast-to-noise ratio (CNR); and evaluated the image quality on pre- and post-NTG coronary MRA in 15 volunteers. Statistical analysis was performed with p value less than 0.05 considered significant. RESULTS: The mean trigger delay and optimal acquisition window were shortened significantly and the mean scanning time was prolonged statistically after NTG administration. There was no significant alteration in terms of apparent SNR and apparent CNR. The lumen diameters were significantly larger in coronary MRA post-NTG than in that of pre-NTG, with an average 25.35% +/- 6.51% (SD) increase, and the left circumflex coronary artery (LCX) had slightly lower vasodilation in comparison with the right coronary artery. Image quality scores of 53 (39.3%, 53/135) segments were increased and 15 segments (11.1%, 15/135) decreased after NTG administration, and the remaining 67 segments (49.6%, 67/135) were unchanged. CONCLUSION: In general, sublingual NTG is useful for improving visualization of the coronary artery lumen and alleviating the impact of artifact. However, several alterations and disadvantages should be taken into consideration in view of the disturbed assessment of vasodilatory response in the LCX and the impaired quality in a minority of segments after NTG administration. Further studies are needed to evaluate the effect of beta-blockade on eliminating the disadvantages of sublingual NTG.

Gd-EOB-DTPA-enhanced MR findings in chemotherapy-induced sinusoidal obstruction syndrome in colorectal liver metastases.

BACKGROUND: We assessed the clinical presentations, biomarkers, and Gd-EOB-DTPA-enhanced MRI features that were associated with oxaliplatin-induced sinusoidal obstruction syndrome (SOS) to detect chemotherapy-associated SOS in a timely manner. METHODS: Fifty-seven patients who underwent oxaliplatin-based chemotherapy and Gd-EOB-DTPA-enhanced MRI were included. Post-oxaliplatin heterogeneity in liver parenchyma was scored on a grading scale of 0 to 3. Abnormal clinical findings, including splenomegaly, hepatomegaly, gall bladder wall thickening, and hepatic vein narrowing, were also assessed. Additionally, alanine transaminase (ALT) levels, aspartate aminotransferase (AST) levels, and platelet counts were measured. RESULTS: For SOS, 21 patients were scored grade 0, 24 were grade 1, seven were grade 2, and five were grade 3. Hepatomegaly, splenomegaly, gall bladder wall thickening, and hepatic vein narrowing were significantly correlated with the grade for non-tumorous hepatic parenchymal heterogeneity. For laboratory findings, ALT and AST levels, the AST-to-platelet ratio index score, and platelet counts were significantly associated with a high grade (≥2) of non-tumorous hepatic parenchymal heterogeneity. CONCLUSIONS: We assessed the clinical presentations, biomarkers, and Gd-EOB-DTPA-enhanced MRI features that were associated with oxaliplatin-induced sinusoidal obstruction syndrome (SOS) to detect chemotherapy-associated SOS in a timely manner. Additionally, specific laboratory findings were significantly associated with a high grade (≥2).

[The value of breath-hold diffusion-weighted imaging in small hepatocellular carcinoma lesion (

OBJECTIVE: To evaluate the added value of single breath-hold diffusion-weighted imaging (DWI) in detection of small HCC lesions (

[Comparative study on clinical and pathological changes of liver fibrosis with diffusion-weighted imaging].

OBJECTIVE: To evaluate the clinical practical value of apparent diffusion coefficient (ADC) measurements based on diffusion-weighted MR imaging (DWI) for quantification of liver fibrosis and inflammation for hepatitis viral infection. METHODS: Diffusion-weighted MRI with parallel imaging was prospectively performed on 85 patients with chronic hepatitis and on 22 healthy volunteers within a single breath-hold using a single-shot spin-echo echo-planar sequence at b values of 100, 300, 500, 800 and 1000 s/mm2 respectively. ADC values of liver were measured with five different b values. The inflammation grades and fibrosis stages were evaluated histologically by biopsy. One-way analysis of variance and Spearman' s rank correlation test were used for statistical analysis. Receiver operating characteristics analysis was used to assess the performance of ADC in predicting the presence of stage > or = 2 and stage > or = 3 hepatic fibrosis, and grade > or = 1 hepatic inflammation. RESULTS: There was moderate negative correlation between hepatic ADC values and fibrosis stage. And the best correlation was obtained for a b value of 800 s/mm2 (r = -0.697, P = 0. 000). At all b values there was a significant decrease in hepatic ADC in patients with stage < or = 1 versus stage > or = 2 fibrosis and stage < or = 2 versus stage > or = 3 fibrosis (P < 0.05). Hepatic ADC was a significant predictor of stage > or = 2 and > or = 3 fibrosis. The areas under the curve were 0.909 vs 0.917, sensitivity 76.6% vs 80.0% and specificity 88.3% vs 91.5% (ADC with a b value of 800 s/mm2, 1.26 x 10(-3) mm2/s or less and 1.19 x 10(-3) mm2/s or less). There was weak to moderate negative correlation between ADCs and inflammation grade. Hepatic ADC was a significant predictor of grade > 1 inflammation with an area under the curve of 0.781, sensitivity of 60.0% and specificity of 86.4% (ADC with a b value of 500 s/mm2, 1.54 x 10(-3) mm2/s or less). CONCLUSION: The DWI measurement of hepatic ADC can be used to quantify liver fibrosis and inflammation. It will be a new approach for early diagnosis and therapeutic follow-up of hepatic fibrosis.

The value of diffusion-weighted imaging in combination with T2-weighted imaging for rectal cancer detection.

OBJECTIVE: To evaluate the clinical value of diffusion-weighted imaging (DWI) in combination with T(2)-weighted imaging (T(2)WI) for the detection of rectal cancer as compared with T(2)WI alone. MATERIALS AND METHODS: Forty-five patients with rectal cancer and 20 without rectal cancer underwent DWI with parallel imaging and T(2)WI on a 1.5 T scanner. Images were independently reviewed by two readers blinded to the results to determine the detectability of rectal cancer. The detectability of T(2)W imaging without and with DW imaging was assessed by means of receiver operating characteristic analysis. The interobserver agreement between the two readers was calculated with kappa statistics. RESULTS: The ROC analysis showed that each of two readers achieved more accurate results with T(2)W imaging combined with DW imaging than with T(2)W imaging alone significantly. The A(z) values for the two readers for each T(2)WI and T(2)WI combined with DWI were 0.918 versus 0.991 (p=0.0494), 0.934 versus 0.997 (p=0.0475), respectively. The values of kappa were 0.934 for T(2)WI and 0.948 for T(2)WI combined with DWI between the two readers. CONCLUSION: The addition of DW imaging to conventional T(2)W imaging provides better detection of rectal cancer.

[Comparison of MRI manifestations and histopathologic findings in pancreatic head carcinoma in vivo ex vivo].

OBJECTIVE: To prospectively analyze the correlation of MRI image characteristics with histopathological findings in pancreatic head carcinoma in vivo and ex vivo. METHODS: Sixteen patients with pancreatic head carcinoma were examined by 1.5T MRI. MR sequences included pre-and post-contrast dynamic 2D FLASH T1WI, TSE T2WI + fat suppressed (FS). All fresh specimens were scanned again within an hour after resection during the Whipple procedure, and were then cut into slices along the direction of MRI scan. The MRI image characteristics were compared with gross and histopathologic findings of the specimens. RESULTS: The tumor size ranged from 1.5 cm x 2.0 cm to 4.8 cm x 4.2 cm with a mean value of 3.6 cm x 3.1 cm. The MRI findings in vivo showed hypointensity in 14 lesions and isointensity in 2, and on 2D FLASH T1WI and TSE T2WI, all lesions displayed mixed intensity except 3 lesions with iso-intensity. During post-contrast dynamic pancreatic parenchymal phase, 15 lesions showed mild enhancement and 11 lesions had ring enhancement sign. Nine lesions displayed progressive irregular moderate enhancement during post-contrast dynamic hepatic phase. Four lesions showed enhancement with iso- and hyperintensity in post-contrast dynamic delayed phase. The MRI findings demonstrated that all lesions ex vivo had hypointensity on 2D FLASH T1 WI and mixed intensity on TSE T2WI + FS. Tumor tissues mainly displayed hypointensity, and the area containing tumor and inflammatory tissue showed iso-intensity on 2D FLASH T1WI. On T2WI + FS, the fibrosis proportion displayed hypo or isointensity, while the tumor and chronic inflammatory tissue demonstrated slight hyperintensity, and the zones of mucous degeneration or pancreatic ductal dilatation displayed hyper-intensity. The ring enhancement of tumor was caused by multiple factors and no obvious enhancement within tumor and fibrosis area were observed during post-contrast dynamic pancreatic parenchymal phase. Progressive irregular enhancement originated from desmoplastic reaction within the tumor during post-contrast dynamic hepatic phase and delayed phase, respectively. CONCLUSION: Pancreatic head carcinomas contain various kinds of tissues. MRI can reveal these pathologic characteristics. No obvious hemorrhage and necrosis within the tumor were observed in this series.

Comparison of gadoxetic acid versus gadopentetate dimeglumine for the detection of hepatocellular carcinoma at 1.5 T using the liver imaging reporting and data system (LI-RADS v.2017).

PURPOSE: The goal of this study was to investigate the Liver Imaging Reporting and Data System (LI-RADS) v.2017 for the categorization of hepatocellular carcinomas (HCCs) with gadoxetic acid compared with gadopentetate dimeglumine-enhanced 1.5-T magnetic resonance imaging (MRI). MATERIAL AND METHODS: We included 141 high-risk patients with 145 pathologically-confirmed HCCs who first underwent gadopentetate dimeglumine-enhanced 1.5-T followed by gadoxetic acid-enhanced 1.5-T MRI. Two independent radiologists evaluated the presence or absence of major HCC features and assigned LI-RADS categories after considering ancillary features on both MRIs. Finally, the sensitivity of LI-RADS category 5 (LR-5) and the frequencies of major HCC features were compared between gadoxetic acid- and gadopentetate dimeglumine-enhanced 1.5-T MRI using the Wilcoxon test. RESULTS: The sensitivity of LR-5 for diagnosing HCCs was significantly different between gadoxetic acid- and gadopentetate dimeglumine-enhanced MRI (73.8% [107/145] vs 26.2% [38/145], P < 0.001; 71% [103/145] vs 29% [42/145], P < 0.001 for reviewers 1 and 2, respectively). Among the major HCC LI-RADS features, capsule appearance was less frequently demonstrated on gadoxetic acid-enhanced MRI than on gadopentetate dimeglumine-enhanced MRI (3.4% [5/145] vs 5.5% [8/145], P = 0.793; 4.1% [6/145] vs 5.5% [8/145], P = 0.87 for reviewers 1 and 2, respectively), and the frequency of arterial hyperenhancement was not significantly different between gadoxetic acid and gadopentetate dimeglumine (89% [129/145] vs 89% [129/145], P = 1.000). In addition, the frequency of a washout appearance was less in the transitional phase (TP) than in the portal venous phase (PVP) on gadoxetic acid-enhanced MRI (43% [46/107] vs 57% [61/107], P = 0.367). CONCLUSION: Gadoxetic acid-enhanced MRI showed a comparable sensitivity to gadopentetate dimeglumine-enhanced MRI for the diagnosis of HCCs, and LI-RADS category 4 (LR-4) hepatic nodules were upgraded to LR-5 when taking into account the major features according to LI-RADS v.2017.

Assessment of T staging and mesorectal fascia status using high-resolution MRI in rectal cancer with rectal distention.

AIM: To determine the accuracy of high-resolution magnetic resonance imaging (MRI) using phased-array coil for preoperative assessment of T staging and mesorectal fascia infiltration in rectal cancer with rectal distention. METHODS: In a prospective study of 67 patients with primary rectal cancer, high-resolution magnetic resonance imaging (in-plane resolution, 0.66 multiply 0.56) with phased-array coil were performed for T-staging and measurement of distance between the tumor and the mesorectal fascia. The assessment of MRI was compared with postoperative histopathologic findings. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were evaluated. RESULTS: The overall magnetic resonance accuracy was 85.1% for T staging and 88% for predicting mesorectal fascia involvement. Magnetic resonance sensitivity, specificity, accuracy, positive predictive value, and negative predictive value was 70%, 97.9%, 89.6%, 93.3% and 88.5% for

[Evaluation of 2D and 3D MRI imaging in the diagnosis of pancreatic carcinoma].

OBJECTIVE: To evaluate various kinds of sequences and modified dynamic contrast-enhanced MRI methods in the diagnosis of pancreatic carcinoma. METHODS: Forty-nine pancreatic carcinoma patients proved by histopathology or clinical examination and follow-up underwent MR examination. Plain MR sequences included: T1-weighted 2D FLASH, T1 WI 3D VIBE, TSE T2 WI and HASTE with FS. Modified dynamic contrast-enhanced scanning procedures were coronal scaning with 3D FLASH and axial scaning using T1 WI 3D VIBE sequences in turn for the upper abdominal area and pancreatic area. The coronal imaging were used to obtain 3D peripancreatic vessels during arterial phase and portal vein phase scanning, respectively. The axial imaging were used to detect the tumor in pancreatic parenchymal phase and delayed phase scanning, respectively. Final scanning for the whole upper abdomen was performed using T1 WI 2D FLASH axial sequence. RESULTS: (1) Of 49 lesions in these patients, 45 showed hypo-intensity and 4 iso-intensity on 3D VIBE. Forty-six lesions showed hypo-intensity and 3 isointensity on 2D FLASH. On TSE T2 + FS, lesion contour was not clear enough; 3 of them displayed isointensity, the other showed iso- or hyper-intensity. (2) During pancreatic parenchymal phase, 48 lesions showed hypo-intensity and 39 ring enhancement. Twenty-four lesions displayed marginal tubercle and inner compartment enhancement during portal vein and delayed phase. Six lesions showed iso- or hyper-intensity in delayed phase. (3) Thirty-seven patients underwent surgical exploration. MRI and MRA had a good correlation with surgical findings for peripancreatic vessels which were diagnosed as being invasive or noninvasive by tumors except three superior mesenteric arteries and four superior mesenteric veins being misdiagnosed. CONCLUSION: As"one-stop-shop" MRI examination, modified MRI sequences consisting of dynamic coronal and axial contrast-enhanced scanning is feasible and helpful in diagnosing, staging and assessing the resectability for pancreatic carcinoma.

[MRI in the evaluation of peripancreatic vessel invasion and resectability of pancreatic carcinoma].

OBJECTIVE: To investigate the role of MRI in evaluating the peripancreatic vessel invasion and resectability of pancreatic carcinoma based on the comparison of MRI image with surgical exploration, and try to establish the criteria for assessment of the sensitivity, specificity and accuracy of resectability. METHODS: Forty-one pancreatic carcinoma patients confirmed by pathology received preoperative plain and contrast enhanced MRI scan, and 37 of them had additional coronal MRA scan. Peripancreatic vessel invasion was preoperatively assessed based on MRI features, and the vessel invasion degree from the uninvolved to the severely involved was divided into 6 grades represented by 1, 2a, 2b, 3a, 3b and 4, respectively. Compared with the findings during the surgery, the sensitivity and specificity of each vessel invasion grade were studied and the receiver operator characteristic curve (ROC) was drawn. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of resectability evaluation based on 2 and 2a degree were calculated respectively. The resectability of involved arteries and veins of grade 2 were also analyzed. RESULTS: Of the 41 patients, 22 had resectable tumor, with 20 curative resection and 2 palliative. Compared with the findings during surgery, seven vessels including three arteries and four veins were not correctly interpreted by MRI. If grade 1,2a,2b,3a and 3b was used as the resectable standard,respectively, the sensitivity to predict the unresectbility was 78.3%, 84.8%, 67.4%, 56.5% and 47.8%, respectively. Receiver operator characteristic curve demonstrated that grade 2a was the optimal critical point. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of grade 2a in predicting the unresectbility were 84.8%, 98.5%, 92.9%, 96.6% and 95.9%. CONCLUSION: Our data showed that grade 2a (tumor involvement < 2 cm long and < 1/2 circumference of the vessel) may be more sensitive and accurate in predicting the resectability, which may be considered as the line of demarcation between the respectable and unresectable cases in clinical practice.

Usefulness of two-point Dixon fat-water separation technique in gadoxetic acid-enhanced liver magnetic resonance imaging.

AIM: To compare differences between volumetric interpolated breath-hold examination (VIBE) using two-point Dixon fat-water separation (Dixon-VIBE) and chemically selective fat saturation (FS-VIBE) with magnetic resonance imaging examination. METHODS: Forty-nine patients were included, who were scanned with two VIBE sequences (Dixon-VIBE and FS-VIBE) in hepatobiliary phase after gadoxetic acid administration. Subjective evaluations including sharpness of tumor, sharpness of vessels, strength and homogeneity of fat suppression, and artifacts that were scored using a 4-point scale. The liver-to-lesion contrast was also calculated and compared. RESULTS: Dixon-VIBE with water reconstruction had significantly higher subjective scores than FS-VIBE in strength and homogeneity of fat suppression (< 0.0001) but lower scores in sharpness of tumor (P < 0.0001), sharpness of vessels (P = 0.0001), and artifacts (P = 0.034). The liver-to-lesion contrast on Dixon-VIBE images was significantly lower than that on FS-VIBE (16.6% ± 9.4% vs 23.9% ± 12.1%, P = 0.0001). CONCLUSION: Dixon-VIBE provides stronger and more homogenous fat suppression than FS-VIBE, while has lower clarity of focal liver lesions in hepatobiliary phase after gadoxetic acid administration.

Potential of Gd-EOB-DTPA-enhanced MR imaging for evaluation of bile duct ligation-induced liver injury in rabbits.

OBJECTIVES: The aim of this study was to evaluate the potential of gadoxetic acid (Gd-EOB-DTPA)-enhanced MRI for assessment of bile duct ligation (BDL)-induced chelostatic liver injury in an animal model by T1 relaxation time measurements and first-pass perfusion analyses. MATERIALS AND METHODS: Twenty-four rabbits were classified into three groups as follows: control group (N group), n = 8; BDL group studied on the 5th postoperative day (BDL-5d group), n = 8; BDL group studied on the 14th postoperative day (BDL-14d group), n = 8. A dual flip angle three-dimensional gradient echo sequence with volumetric interpolated breath-hold examination was performed before and at 20 min [hepatobiliary phase (HBP)] after Gd-EOB-DTPA administration. Besides, early dynamic contrast-enhanced MRI was performed for 4.32 min with a temporal resolution of 2.2 s. T1 relaxation times of liver parenchyma were measured and perfusion parameters were calculated. RESULTS: Dilatation of intra-hepatic bile duct was found only in the BDL-14d group. HBP T1 relaxation times of the BDL-5d and BDL-14d groups were significantly prolonged (p < 0.001) and the enhancement slope percentage of BDL-5d and BDL-14d groups were significantly lowered in comparison with that of the N group (p < 0.001). There were no differences between the BDL-5d group and the BDL-14d group for HBP T1 relaxation times and the enhancement slope percentage (p > 0.05). Area under the receiver operating characteristic curve of HBP T1 relaxation time and the enhancement slope percentage for the selection of chelostatic liver were 0.98 and 0.92 for the BDL-5d group, and 0.96 and 0.98 for the BDL-14d group, respectively. CONCLUSIONS: HBP T1 relaxation time measurement in combination with first-pass enhancement slope percentage withhold promise to assess extrahepatic chelostatic liver injury.

Enhancement patterns of small hepatocellular carcinoma shown by dynamic MRI and CT.

OBJECTIVES: To study prospectively the enhancement features of small hepatocellular carcinoma (SHCC) with multi-phase scanning of dynamic MRI and spiral CT, and discuss the superiority of dynamic MRI to spiral CT. METHODS: Multi-phase dynamic contrast scanning of high field MRI and spiral CT were performed in 53 patients with SHCC. The arterial phase, portal venous phase and delayed phase scanning of spiral CT was done after the pre-contrast scanning of the entire liver. MRI was performed with SE sequence and fast multiplanar spoiled gradient-recalled sequence dynamic multi-phase contrast scanning. RESULTS: Seventy-six lesions were found in all 53 patients. Sixty-nine and 54 of the 76 lesions enhanced obviously in MRI and spiral CT arterial phase scanning respectively. The typical enhancement patterns of SHCC in the arterial phase, portal venous phase and delayed phase scanning of MRI and spiral CT were hyper-hypo-hypointense (dense) and hyper-iso-hypointense (dense). Atypical enhancement patterns were hyper-hyper-hyperintense (dense), hyper-iso-isointense (dense) and hypo-hypo-hypointense (dense). CONCLUSIONS: Both MRI and spiral CT multi-phase dynamic contrast-enhanced scanning could demonstrate the enhancement features of SHCC, and arterial phase scan of MRI was superior to spiral CT in reflecting the hypervascular characterization of SHCC. In addition, MRI was better than spiral CT in characterization of hepatic lesions combined with SE sequence.

Preoperative evaluation of colorectal liver metastases: comparison of gadopentetate dimeglumine and gadoxetic-acid-enhanced 1.5-T MRI.

PURPOSE: The aim of this study was to compare the diagnostic performance of gadopentetate dimeglumine and gadoxetic-acid-enhanced MRI in patients with colorectal liver metastases. METHODS: Thirty patients were included and divided into three sets, as follows: gadopentetate dimeglumine set-hepatic arterial phase, portal venous phase, and delay phase; gadoxetic acid set-hepatic arterial phase, portal venous phase, and delay phase; combined set-gadoxetic acid set and hepatobiliary phase. The accuracy was assessed by the area under the alternative-free response receiver operating characteristic curve; the sensitivity and positive predictive value were calculated. RESULTS: There were 81 colorectal liver metastases in all. Both readers noted higher diagnostic accuracies of the combined set than the other two sets. In the group of small lesions, both readers detected significantly higher sensitivities and positive predictive value on the combined set than the other two sets. CONCLUSIONS: The combined set showed higher accuracy and sensitivity, especially significantly higher accuracy and sensitivity on small lesions.

A study of in vitro and in vivo MR of free-breathing whole-heart 3D coronary angiography using parallel imaging.

To evaluate parallel-imaging methods in free-breathing whole-heart 3D coronary magnetic resonance angiography and assess the navigator techniques and visualization rates of the major coronary arteries. We compared key parameters of the generalized autocalibrating partially parallel acquisition and modified sensitive encoding images in vitro phantom MRI; performed the MRA with GRAPPA parallel imaging in healthy volunteers; compared 1D- and 2D-prospective acquisition correction and analyzed the differences; and evaluated the visualization of major coronary arterial branches. GRAPPA images had higher signal-to-noise ratio and contrast-to-noise ratio and fewer aliasing artifacts. The coronary arteries were adequately visualized in 38 volunteers. 2D-PACE had a higher navigator efficiency, shorter scan time, and gave clearer reconstructed images in comparison with 1D-PACE. GRAPPA images were superior to mSENSE images. Whole-heart 3D coronary MRA along with parallel-imaging technique is a potential clinical method, and 2D-PACE is a better navigation technique than 1D-PACE.