Effect of isoflurane anesthesia and hypothermia on the hepatic kinetics of Gd-EOB-DTPA: evaluation using MRI of conscious mice

Purpose:

To develop a method for body magnetic resonance imaging (MRI) of conscious mice and investigate the effect of isoflurane anesthesia and hypothermia on the hepatic kinetics of gadoxetate disodium (Gd‐EOB‐DTPA).

Materials and Methods:

Conscious or anesthetized mice were restrained on a holder and the rectal temperature was measured serially. Serial MRI of the liver was performed after intravenous injection of Gd‐EOB‐DTPA with or without temperature control. Three mice were studied for each condition.

Results:

The temperature dropped rapidly in anesthetized mice beside the MR unit. The decline was less prominent in conscious mice. The temperature decreased less in anesthetized mice and remained constant in conscious mice in the radiofrequency (RF) coil. The washout of Gd‐EOB‐DTPA was slower in anesthetized hypothermic mice than in conscious normothermic mice. Warmed anesthetized mice showed faster washout, and cooled conscious mice showed delayed washout. Severer hypothermia in anesthetized mice resulted in weaker initial enhancement and slower washout.

Conclusion:

By separately manipulating the presence or absence of anesthesia and hypothermia, we demonstrated that washout of Gd‐EOB‐DTPA was delayed under hypothermia, regardless of anesthesia. Serial body MRI of conscious mice was feasible and allowed the evaluation of kinetics of a contrast agent, while excluding the possible effects of anesthesia. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Gadoxetic acid disodium-enhanced magnetic resonance imaging for biliary and vascular evaluations in preoperative living liver donors: comparison with gadobenate dimeglumine-enhanced MRI

Purpose

To compare gadoxetic acid disodium (Gd‐EOB‐DTPA)‐enhanced magnetic resonance imaging (MRI) with gadobenate dimeglumine (Gd‐BOPTA)‐enhanced MRI in preoperative living liver donors for the evaluation of vascular and biliary variations.

Materials and Methods

Sixty‐two living liver donors who underwent preoperative MRI were included in this study. Thirty‐one patients underwent MRI with Gd‐EOB‐DTPA enhancement, and the other 31 underwent MRI with Gd‐BOPTA enhancement. Two abdominal radiologists retrospectively reviewed dynamic T1‐weighted and T1‐weighted MR cholangiography images and ranked overall image qualities for the depiction of the hepatic artery, portal vein, hepatic vein, and bile duct on a 5‐point scale and determined the presence and types of normal variations in each dynamic phase. Semiquantitative analysis for bile duct visualization was also conducted by calculating bile duct‐to‐liver contrast ratios.

Results

No statistical differences were found between the two contrast media in terms of hepatic artery or bile duct image quality by the two reviewers, or in terms of portal vein image quality by one reviewer (P > 0.05). Gd‐BOPTA provided better image qualities than Gd‐EOB‐DTPA for the depiction of hepatic veins by both reviewers, and for the depiction of portal veins by one reviewer (P < 0.01). The two contrast media‐enhanced images had similar bile duct‐to‐liver contrast ratios (P > 0.05). Regarding diagnostic accuracies with hepatic vascular/biliary branching types, no significant differences were observed between the two contrast media (P > 0.05).

Conclusion

Gd‐EOB‐DTPA could be as useful as Gd‐BOPTA for the preoperative evaluation of living liver donors, and has the advantage of early hepatobiliary phase image acquisition. J. Magn. Reson. Imaging 2011;33:149–159. © 2010 Wiley‐Liss, Inc.     

Dilution method of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd‐EOB‐DTPA)‐enhanced magnetic resonance imaging (MRI)

Purpose

To elucidate whether a contrast agent dilution method (dilution method), in which gadoxetate disodium (Gd‐EOB‐DTPA) is diluted with saline, is useful for good‐quality arterial‐phase images.

Materials and Methods

In this study we observed 494 hypervascular hepatocellular carcinomas (HCCs) in 327 patients with chronic liver disease. Three Gd‐EOB‐DTPA injection methods were adopted for comparison: 1) test injection method (undiluted Gd‐EOB‐DTPA and modified scan delay), in which a test dose of 0.5 mL of Gd‐EOB‐DTPA was injected to determine scan delay; 2) conventional method (undiluted Gd‐EOB‐DTPA and fixed scan delay); and ( 3 ) dilution method (diluted Gd‐EOB‐DTPA and fixed scan delay), in which Gd‐EOB‐DTPA was diluted to 20 mL with saline. Lesion‐liver contrast was calculated. Image quality and lesion detectability were evaluated by two radiologists blinded to the injection methods.

Results

The lesion‐liver contrast of the dilution method was significantly higher than that of the other two methods. Lesion detectability of the conventional method (64%) was significantly lower than that of the other two methods (contrast agent dilution method, 95%; test injection method, 93%). The image quality of the contrast agent dilution method was significantly better than that of the other two methods.

Conclusion

The dilution method contributed to improved image quality, high lesion‐liver contrast, and high lesion detectability in the arterial‐phase images of GD‐EOB‐DTPA‐enhanced MRI. J. Magn. Reson. Imaging 2009;30:849–854. © 2009 Wiley‐Liss, Inc.     

Dynamic contrast‐enhanced magnetic resonance imaging of abdominal solid organ and major vessel: Comparison of enhancement effect between Gd‐EOB‐DTPA and Gd‐DTPA

Purpose

To evaluate the differences in enhancement of the abdominal solid organ and the major vessel on dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) obtained with gadolinium ethoxybenzyldiethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA: EOB) and gadolinium diethylenetriamine pentaacetic acid (Gd‐DTPA) in the same patients.

Materials and Methods

A total of 13 healthy volunteers underwent repeat assessments of abdominal MR examinations with DCE‐MRI using either Gd‐DTPA at a dose of 0.1 mmol/kg body weight or EOB at a dose of 0.025 mmol/kg body weight. DCE images were obtained at precontrast injection and in the arterial phase (AP: 25 seconds), portal phase (PP: 70 seconds), and equilibrium phase (EP: 3 minutes). The signal intensities (SIs) of liver at AP, PP, and EP; the SIs of spleen, renal cortex, renal medulla, pancreas, adrenal gland, aorta at AP; and the SIs of portal vein and inferior vena cava (IVC) at PP were defined using region‐of‐interest measurements, and were used for calculation of signal intensity ratio (SIR).

Results

The mean SIRs of liver (0.195 ± 0.140), spleen (1.35 ± 0.353), renal cortex (1.58 ± 0.517), renal medulla (0.548 ± 0.259), pancreas (0.540 ± 0.183), adrenal gland (1.04 ± 0.405), and aorta (2.44 ± 0.648) at AP as well as the mean SIRs of portal vein (1.85 ± 0.477) and IVC (1.16 ± 0.187) at PP in the EOB images were significantly lower than those (0.337 ± 0.200, 1.99 ± 0.443, 2.01 ± 0.474, 0.742 ± 0.336, 0.771 ± 0.227, 1.26 ± 0.442, 3.22 ± 1.20, 2.73 ± 0.429, and 1.68 ± 0.366, respectively) in the Gd‐DTPA images (P < 0.05 each). There was no significant difference in mean SIR of liver at PP between EOB (0.529 ± 0.124) and Gd‐DTPA (0.564 ± 0.139). Conversely, the mean SIR of liver at EP was significantly higher with EOB (0.576 ± 0.167) than with Gd‐DTPA (0.396 ± 0.093) (P < 0.001).

Conclusion

Lower arterial vascular and parenchymal enhancement with Gd‐EOB, as compared with Gd‐DTPA, may require reassessment of its dose, despite the higher late venous phase liver parenchymal enhancement. J. Magn. Reson. Imaging 2009;29:636–640. © 2009 Wiley‐Liss, Inc.     

Different signal intensity at Gd-EOB-DTPA compared with Gd-DTPA-enhanced MRI in hepatocellular carcinoma transgenic mouse model in delayed phase hepatobiliary imaging

Purpose:

To evaluate hyperintense Gd‐DTPA‐ compared with hyper‐ and hypointense Gd‐EOB‐DTPA‐enhanced magnet resonance imaging (MRI) in c‐myc/TGFα transgenic mice for detecting hepatocellular carcinoma (HCC).

Materials And Methods:

Twenty HCC‐bearing transgenic mice with overexpression of the protooncogene c‐myc and transforming growth factor‐alpha (TGF‐α) were analyzed. MRI was performed using a 3‐T MRI scanner and an MRI coil. The imaging protocol included Gd‐DTPA‐ and Gd‐EOB‐DTPA‐enhanced T1‐weighted images. The statistically evaluated parameters are signal intensity (SI), signal intensity ratio (SIR), contrast‐to‐noise ratio (CNR), percentage enhancement (PE), and signal‐to‐noise ratio (SNR).

Results:

On Gd‐DTPA‐enhanced MRI compared with Gd‐EOB‐DTPA‐enhanced MRI, the SI of liver was 265.02 to 573.02 and of HCC 350.84 to either hyperintense with 757.1 or hypointense with 372.55 enhancement. Evaluated parameters were SNR of HCC 50.1 to 56.5/111.5 and SNR of liver parenchyma 37.8 to 85.8, SIR 1.32 to 1.31/0.64, CNR 12.2 to 26.1/?30.08 and PE 42.08% to 80.5/?98.2%, (P < 0.05).

Conclusion:

Gd‐EOB‐DTPA is superior to Gd‐DTPA for detecting HCC in contrast agent‐enhanced MRI in the c‐myc/TGFα transgenic mouse model and there was no difference between the hyperintense or hypointense appearance of HCC. Either way, HCCs can easily be distinguished from liver parenchyma in mice. J. Magn. Reson. Imaging 2012;35:1397–1402. © 2012 Wiley Periodicals, Inc.

     

Liver parenchymal enhancement of hepatocyte‐phase images in Gd‐EOB‐DTPA‐enhanced MR imaging: Which biological markers of the liver function affect the enhancement?

Purpose:

To clarify the factors that predict enhancement of the liver parenchyma in hepatocyte‐phase of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd‐EOB‐DTPA)‐enhanced MR imaging.

Materials and Methods:

Gd‐EOB‐DTPA–enhanced hepatocyte‐phase MR images of 198 patients with chronic liver diseases (Child‐Pugh class A in 112 patients, class B in 74 patients, and class C in 12 patients) were retrospectively analyzed. The hepatocyte‐phase images were obtained using fat‐suppressed T1‐weighted gradient‐echo images with a 3D acquisition sequence 10 min and 20 min after IV administration of Gd‐EOB‐DTPA (0.025 mmol/kg body weight). The quantitative liver–spleen contrast ratio (Q‐LSC) was calculated using the signal intensities of the liver and spleen. Serum albumin levels, total bilirubin levels, prothrombin activity, and the results of indocyanine green clearance tests (ICGs) were recorded and correlated with the Q‐LSC. Logistic regression analysis was performed to analyze which factors predict sufficient liver enhancement using a Q‐LSC of 1.5 as a cutoff value.

Results:

Only ICGs and Child‐Pugh classifications showed a statistically significant correlation with the Q‐LSC. Logistic regression analysis showed that ICGs were the only factors that accurately predicted liver enhancement on hepatocyte‐phase images.

Conclusion:

ICGs were found to be predictors of sufficient liver enhancement on hepatocyte‐phase images. J. Magn. Reson. Imaging 2009;30:1042–1046. © 2009 Wiley‐Liss, Inc.     

Can MR fluoroscopic triggering technique and slow rate injection provide appropriate arterial phase images with reducing artifacts on gadoxetic acid‐DTPA (Gd‐EOB‐DTPA)‐enhanced hepatic MR imaging?

Purpose:

To evaluate whether using MR fluoroscopic triggering technique and slow rate injection improves the quality of arterial phase images in gadoxetic acid‐DTPA‐enhanced (Gd‐EOB‐DTPA) MR imaging because of proper acquisition timing and reduction of artifacts.

Materials and Methods:

Two hundred sixteen patients undergoing examination for liver diseases were retrospectively reviewed. All MR images were obtained with two Gd‐EOB‐DTPA injection protocols: (i) a combination protocol, in which the MR fluoroscopic triggering technique and slow rate injection (1 mL/s) were used; and for comparison, (ii) a conventional protocol, in which adjusted fixed scan delay and ordinary rate injection (2 mL/s) were adopted. Signal‐to‐noise ratio (SNR) of aorta, portal vein, and liver parenchyma on arterial phase images were calculated. Two blinded readers independently evaluated the obtained arterial phase images in terms of acquisition timing and degree of artifacts.

Results:

The SNRs of aorta and portal vein on arterial phase images were significantly higher in the combination protocol group (aorta/portal: 221.9 ± 91.9/197.1 ± 89.8) than that in the conventional protocol group (aorta/portal: 169.8 ± 97.4/92.7 ± 48.5) (P < 0.05). The acquisition timing for arterial phase images with the combination protocol was significantly better than that with the conventional protocol (P < 0.01). The image quality of the combination protocol was significantly higher than that of the conventional protocol (P < 0.01). The occurrence rate of moderate or severe degree of artifacts in the conventional protocol (38.0%) was more prominent than that in the combination protocol (18.5%).

Conclusion:

The combination of the MR fluoroscopic triggering technique and slow rate injection provides proper arterial phase images and reduces the artifacts in Gd‐EOB‐DTPA MR imaging. J. Magn. Reson. Imaging 2010;32:334–340. © 2010 Wiley‐Liss, Inc.     

Gd‐EOB‐DTPA‐enhanced MR imaging: Prediction of hepatic fibrosis stages using liver contrast enhancement index and liver‐to‐spleen volumetric ratio

Purpose:

To develop and evaluate a quantitative parameter for staging hepatic fibrosis by contrast enhancement signal intensity and morphological measurements from gadoxetic acid (Gd‐EOB‐DTPA)‐enhanced MR imaging.

Materials and Methods:

MR images were obtained in 93 patients; 75 patients had histopathologically proven hepatic fibrosis and 18 patients who had healthy livers were evaluated. The liver‐to‐muscle signal intensity ratio (SI_post = SIliver/SImuscle), contrast enhancement index (CEI = SIpost/SIpre), and liver‐to‐spleen volumetric ratio (VR = Vliver/Vspleen) were evaluated for staging hepatic fibrosis.

Results:

VR was most strongly correlated with fibrosis stage (7.21; r = ?0.83; P < 0.001). Sensitivity, specificity, and area under the ROC curve demonstrated by linear regression formula generated by VR and CEI in predicting fibrous scores were 100%, 73%, and 0.91, respectively, for the detection of hepatic fibrosis F1 or greater (≥ F1),100%, 87%, and 0.96 for ≥ F2, 74%, 98%, and 0.93 for ≥ F3 and 91%, 100%, and 0.97 for F4.

Conclusion:

The liver‐to‐spleen volumetric ratio and contrast enhancement index were reliable biomarkers for the staging of hepatic fibrosis on Gd‐EOB‐DTPA‐enhanced MR imaging. J. Magn. Reson. Imaging 2012;36:1148–1153. © 2012 Wiley Periodicals, Inc.

     

梗阻性淋巴水肿淋巴动力学异常的实验观察

目的探讨间质MR淋巴造影对评价淋巴动力学的价值. 材料与方法用改良的Danese手术方法在13只新西兰大白兔后肢一侧形成淋巴水肿模型,另一侧作为对照.在每只大白兔双侧后肢足背部趾蹼处注射0.2 ml欧乃影,按摩注射部位30 s.分别于对比剂注射前后进行三维MR淋巴造影及延迟淋巴造影成像.测量不同延迟时间引流区域淋巴结的信号强度,绘制时间-信号强度曲线. 结果对照侧窝淋巴结、腹股沟淋巴结、髂淋巴结/后腹膜淋巴结分别于注射对比剂10、20、30 min后信号强度达到峰值.实验侧在淋巴水肿的不同时期出现不同程度的引流远端腹股沟及髂窝淋巴结信号强度峰值高度及峰值时间下降和延迟. 结论间质MR淋巴造影可以定量地评价引流区域淋巴动力学的状况.     

Gadoxetic acid-enhanced MRI findings of early hepatocellular carcinoma as defined by new histologic criteria

Purpose:

To describe the imaging features of early hepatocellular carcinoma (HCC) on gadoxetic acid‐enhanced MRI (Gd‐EOB‐MRI) in comparison with multidetector computed tomography (MDCT) examinations.

Materials and Methods:

We analyzed imaging findings of 19 pathologically proven early HCC lesions in 15 patients who underwent both MDCT and Gd‐EOB‐MRI at 3.0 Tesla (T) units before surgery. MRI included in‐phase and out‐of‐phase T1‐weighted dual‐echo gradient‐recalled‐echo sequences, dynamic T1‐weighted images before and after bolus injection of gadoxetic acid disodium, fat‐saturated T2‐weighted fast spin‐echo sequences, and T1‐weighted hepatobiliary phase images 20 min after contrast injection. Two radiologists retrospectively evaluated the signal intensities and enhancement features on MRI and MDCT.

Results:

None of the lesions displayed arterial enhancement and washout on MDCT. On Gd‐EOB‐MRI, six (32%) lesions showed T2‐hyperintensity, five (26%) lesions showed signal drop on opposed‐phase. Three lesions (16%) showed arterial enhancement and washout. Twelve (63%), 13 (68%), and 15 (79%) lesions were hypointense on hepatic venous, equilibrium, and hepatobiliary phase, respectively.

Conclusion:

Most early HCCs did not show arterial enhancement and washout pattern on both MDCT and Gd‐EOB‐MRI. Gd‐EOB‐MRI may provide several ancillary findings for diagnosis of early HCC such as decreased hepatobiliary uptake, T2 hyperintensity and signal drop in opposed phase. J. Magn. Reson. Imaging 2012;393‐398. © 2011 Wiley Periodicals, Inc.     

Hepatocellular carcinoma in a North American population: Does hepatobiliary MR imaging with Gd‐EOB‐DTPA improve sensitivity and confidence for diagnosis?

Purpose:

To evaluate the value of hepatobiliary phase imaging for detection and characterization of hepatocellular carcinoma (HCC) in liver MRI with Gd‐EOB‐DTPA, in a North American population.

Materials and Methods:

One hundred MRI examinations performed with the intravenous injection of Gd‐EOB‐DTPA in patients with cirrhosis were reviewed retrospectively. Nodules were classified as HCC (n = 70), indeterminate (n = 33), or benign (n = 22). Five readers independently reviewed each examination with and without hepatobiliary phase images (HBP). Lesion conspicuity scores were compared between the two readings. Lesion detection, confidence scores, and receiver operating characteristic (ROC) analysis were compared.

Results:

Lesion detection was slightly improved for all lesion types with the inclusion of the HBP, and was substantially higher for small HCCs (96.0% versus 85.3%). Mean confidence scores for the diagnosis of HCC increased for HCCs overall and each size category (P < 0.001). Diagnostic performance improved with the addition of the HBP (aggregate AROC 87.7% versus 80.0%, P < 0.01), and sensitivity for characterization improved (90.9% versus 78.3%, P < 0.01) while specificity was unchanged.

Conclusion:

Hepatobiliary phase imaging may improve small lesion detection (<1 cm) and characterization of lesions in general, in MRI of the cirrhotic liver with Gd‐EOB‐DTPA. J. Magn. Reson. Imaging 2013;37:398–406. © 2012 Wiley Periodicals, Inc.     

Usefulness of Gd‐EOB‐DTPA‐enhanced MR imaging in the evaluation of simple steatosis and nonalcoholic steatohepatitis

Purpose:

To evaluate the usefulness of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd‐EOB‐DTPA)‐enhanced MR imaging (EOB‐MRI) in differentiating between simple steatosis and nonalcoholic steatohepatitis (NASH), as compared with MR in‐phase/out‐of‐phase imaging. The correlations between the MR features and histological characteristics were preliminarily investigated.

Materials and Methods:

From April 2008 to October 2011, 25 patients (13 simple steatosis and 12 NASH) who underwent both EOB‐MRI and in‐phase/out‐of‐phase imaging were analyzed. The hepatobiliary‐phase enhancement ratio and signal intensity loss on opposed‐phase T1‐weighted images (fat fraction) were compared between the simple steatosis and NASH groups. In the simple steatosis and NASH groups, the correlations between enhancement ratio and histological grade/stage were explored. In the NASH group, fat fraction was correlated with the steatosis score.

Results:

The enhancement ratio in NASH was significantly lower than that in simple steatosis (P = 0.03). In the simple steatosis and NASH groups, the enhancement ratio was significantly correlated with the fibrosis stage (r = ?0.469, P = 0.018). Fat fraction in NASH was strongly correlated with the steatosis score (r = 0.728, P = 0.007).

Conclusion:

In simple steatosis and NASH, the hepatobiliary‐phase enhancement ratio of EOB‐MRI showed significant association with fibrosis stage, and may be a useful discriminating parameter compared with the fat fraction measured by in‐phase/out‐of‐phase imaging. J. Magn. Reson. Imaging 2012;37:1137–1143. © 2012 Wiley Periodicals, Inc.

     

Optimal scanning protocol of arterial dominant phase for hypervascular hepatocellular carcinoma with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced MR

Purpose:

To investigate optimal delay time of hepatic arterial phase in Gadoxetate‐enhanced MR for detecting hypervascular hepatocellular carcinoma (HCC).

Materials and Methods:

Forty‐five patients with 85 hypervascular HCCs and 9 patients with 16 hypervascular HCCs underwent Gadoxetate‐ and Gd‐DTPA‐enhanced MR at 1.5 Tesla (T) system, respectively. All HCCs were analyzed 10–38 s after injection using a time‐resolved dynamic MR sequence with keyhole data sampling. Seven sequential phase images (1 phase = 4 s) were obtained during a single breath hold of 28 s. Time–intensity curves of the abdominal aorta, liver parenchyma, and HCC were obtained, then aortic contrast arrival time, time of peak HCC enhancement, duration time of HCC and aortic enhancement, and time delay from aortic contrast arrival to peak enhancement of HCC were measured.

Results:

Aortic contrast arrival time was 15.1 ± 2.9 s, time of peak HCC enhancement 29.9 ± 4.6 s, duration time of HCC enhancement 17.4 ± 6.4 s postinjection of Gadoxetate. Duration of aortic enhancement (23.6 ± 3.5 s) of Gadoxetate‐enhanced MR was significantly less than that of Gd‐DTPA‐enhanced MR (26.3 ± 2.8 s) (P < 0.0059).

Conclusion:

Peak enhancement time of HCC on Gadoxetate‐enhanced MR imaging occurred at 14.6 ± 4.6 s after aortic contrast arrival. J. Magn. Reson. Imaging 2011;33:864–872. © 2011 Wiley‐Liss, Inc.     

Effect of Gd-DTPA-BMA on choline signals of HT29 tumors detected by in vivo 1H MRS

Purpose

To study the impact of Gd‐DTPA‐BMA on choline signals of HT29 colon carcinomas determined by localized ¹H MRS in vivo at 4.7T.

Materials and Methods

PRESS ¹H MR spectra (2‐second repetition time and echo times of 20–272 msec) were acquired from HT29 xenografts prior to and following intravenous administration of 0.1 or 0.2 mmol/kg Gd‐DTPA‐BMA. The magnetic resonance spectroscopy (MRS) data were analyzed by 1) normalizing choline and water peak areas to their precontrast values; and 2) estimating absolute choline concentration relative to tissue water.

Results

Changes in the T₁ and T₂ of choline and water were apparent following administration of Gd‐DTPA‐BMA. Administration of 0.1 mmol/kg Gd‐DTPA‐BMA induced significant increases in the choline peak area, concomitant with enhancements of the water peak area, whereas 0.2 mmol/kg Gd‐DTPA‐BMA induced no enhancement of choline peak area but significant increases in water peak area at short echo times.

Conclusion

The effect of Gd‐DTPA‐BMA on estimation of tumor choline concentration varied with the dose of contrast agent, the echo time, and the time after contrast agent administration. These data highlight the potential pitfalls associated with the modulation of choline and water signals post‐Gd‐DTPA‐BMA and may account for the apparently contradictory results previously reported. J. Magn. Reson. Imaging 2008;28:1201–1208. © 2008 Wiley‐Liss, Inc.     

Comparison of high spatial resolution respiratory triggered inversion recovery‐prepared spoiled gradient echo sequence with standard breathhold T1 sequence MRI of the liver using gadoxetic acid

Purpose:

To assess if a high resolution respiratory triggered inversion recovery prepared GRE sequence (RT) improved image quality and detection of lesions compared with breathhold GRE T1 weighted MR sequence (BH) in the hepatobiliary uptake phase of MR of the liver using gadoxetic acid (Gd‐EOB‐DTPA).

Materials and Methods:

Thirty‐eight consecutive patients from July 2009 to September 2010 who had undergone Gd‐EOB‐DTPA enhanced liver exams were retrospectively identified. Qualitative assessment performed on reference lesions and background liver by two independent readers. Quantitative assessment performed by one reader.

Results:

Liver parenchyma signal‐to‐noise ratio for BH was 90.3 ± 23.9 (mean ± SD) and RT, 106.1 ± 40.4 (P = 0.119). For BH, 320 lesions were detected compared with 257 for RT. Lesion to liver contrast was significantly better on RT sequences (0.26 ± 0.24; mean ± SD) compared with BH sequence (0.21 ± 0.20; P = 0.044). Fifty‐seven reference lesions assessed. Both reviewers rated BH better for lesion margin and hepatic vessel sharpness. BH was rated with less artifact (P < 0.05). Lesion to liver contrast on BH was significantly better for one reviewer.

Conclusion:

BH sequence had better overall image quality than RT in several quantitative and qualitative factors including number of lesions detected and level of artifact. J. Magn. Reson. Imaging 2013;37:700—706. © 2013 Wiley Periodicals, Inc.     

Effect of Gd‐EOB‐DTPA on T2‐weighted and diffusion‐weighted images for the diagnosis of hepatocellular carcinoma

Purpose:

To evaluate the effect of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA) on T2‐weighted imaging (T2WI) and diffusion‐weighted imaging (DWI) for the diagnosis of hepatocellular carcinoma (HCC).

Materials and Methods:

The phantom signal intensity was measured. We also evaluated 72 patients including 30 patients with HCC. T2WI and DWI were obtained before and then 4 and 20 min after injecting the contrast medium. The signal to noise ratio (SNR), contrast to noise ratio (CNR), and apparent diffusion coefficient (ADC) were calculated in the tumor and liver parenchyma.

Results:

The phantom signal intensity increased on T2WI at a concentration of contrast medium less than 0.2 mmol/L but decreased when the concentration exceeded 0.4 mmol/L. SNR of the liver parenchyma on T2WI was significantly different between before and 4 min after injecting the contrast medium, while there were no significant differences between before and 4 and 20 min after injection. On T2WI, SNR, and CNR of HCC showed no significant differences at any time. SNR, CNR, and ADC of the liver parenchyma and tumor on DWI also showed no significant differences at any time.

Conclusion:

It is acceptable to perform T2WI and DWI after injection of Gd‐EOB‐DTPA for the diagnosis of HCC. J. Magn. Reson. Imaging 2010;32:229–234. © 2010 Wiley‐Liss, Inc.     

Comparison of Gd [DTPA-bis (2-aminoethoxy) ethane] polymeric contrast agent with gadodiamide injection for interstitial MR lymphography: experimental study with rabbits

PURPOSE: To compare the differences between macromolecular and small molecular contrast agents in interstitial magnetic resonance (MR) lymphography. MATERIALS AND METHODS: In two groups of rabbits (N = 12 each), 0.5-mL volumes of 0.5 M and 0.1 M gadodiamide, respectively, were injected subcutaneously into the dorsal feet of both hind legs. After a 24-hour interval, 0.5 mL of Gd [DTPA-bis (2-aminoethoxy) ethane] polymeric contrast agent (Gd-poly-DTPA-EOEA) injection (0.1 M) was injected into the same sites in each rabbit. T1-weighted three-dimensional gradient-echo and maximum intensity projection (MIP) images were obtained before and after the administration of each agent. The nodal maximum short-axis diameter (MSAD) and signal-to-noise ratio (SNR) at each time point were measured. Postmortem measurements of nodal MSADs were also performed. The nodal MSAD measurements obtained by MR lymphography were compared with the postmortem measurements. As an additional control experiment, six rabbits received a subcutaneous injection of 0.5 mL of 0.1 M gadodiamide at the same sites as those described above. This procedure was repeated after a 24-hour interval to determine whether the first injected gadodiamide had any effect on the performance of the subsequently injected agent, by comparing the differences in nodal MSADs obtained by MR lymphography after each injection. RESULTS: Gd-poly-DTPA-EOEA showed a significantly longer enhancement plateau compared to gadodiamide. In comparison with postmortem measurements, nodal measurements by MR lymphography with Gd-poly-DTPA-EOEA at the peak-enhancement phase revealed no significantly different MSADs (P > 0.05), whereas nodal measurements by MR lymphography with gadodiamide showed significantly smaller MSADs (P < 0.05). A comparison of the nodal MSADs measured in two gadodiamide-enhanced MR examinations after the 24-hour interval showed no significant difference (P > 0.05). CONCLUSION: Interstitial MR lymphography with polymeric Gd-poly-DTPA-EOEA enhancer enables more sufficient and reliable visualization of lymph nodes compared to small molecular gadodiamide.     

Hypointense hepatocellular nodules on hepatobiliary phase of Gd‐EOB‐DTPA‐enhanced MRI: Can increasing the flip angle improve conspicuity of lesions?

Purpose:

To compare the conspicuity of hypointense hepatocellular nodules in patients with chronic liver disease on hepatobiliary phase (HP) of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA)‐enhanced magnetic resonance imaging (MRI) acquired with low to high flip angles (FAs).

Materials and Methods:

A total of 95 patients with chronic liver disease who underwent Gd‐EOB‐DTPA‐enhanced MRI were included. HP images were obtained at 20 minutes, with 15°, 20°, and 30° FAs. For the detected hepatocellular nodule, liver‐to‐lesion contrast‐to‐phantom ratios (CPR) and lesion conspicuity (LCS) were assessed.

Results:

In all examinations, 96 hepatocellular nodules showing hypointensity on HP were identified. These lesions included 39 hypovascular nodules and 57 hypervascular nodules. Mean CPR and LCS showed the highest value on the 30° FA, followed by 20° and 15° FAs. CPR and LCS of 15° FA were significantly lower than those of 20° and 30° FAs (P < 0.001 to P = 0.007). CPR of 30° FA for hypervascular nodules was significantly greater than that of 20° FA (P < 0.001).

Conclusion:

In the evaluation of hypointense hepatocellular nodules on HP of Gd‐EOB‐DTPA‐enhanced MRI, higher FA such as 30° should be used rather than low FA such as 15°. J. Magn. Reson. Imaging 2013;37:1093–1099. © 2012 Wiley Periodicals, Inc.     

Detectability of hepatocellular carcinoma by gadoxetate disodium‐enhanced hepatic MRI: Tumor‐by‐tumor analysis in explant livers

Purpose:

To investigate the detectability of hepatocellular carcinoma (HCC) on Gd‐EOB‐enhanced MR images (Gd‐EOB‐MRI), we performed tumor‐by‐tumor analysis of pathologically confirmed tumors using explants from cirrhotic patients who had undergone liver transplantation.

Materials and Methods:

We studied 11 explanted livers and classified the tumor intensity during the arterial phase (AP) and the hepatobiliary phase (HBP) as low in HBP with early enhancement (EE) in AP (A), as high in HBP with EE in AP (B), as low in HBP without EE in AP (C), as high in HBP without EE in AP (D), and as iso‐intense in HBP with EE in AP (E). The diagnostic criteria for HCC were (i) pattern A and C, (ii) pattern A and E, (iii) pattern C and E, and (iv) patterns A, C, and E.

Results:

Of the 71 HCCs, 22 were not detected at MRI; of these, 9 were moderately differentiated and 13 were well‐differentiated HCCs. The sensitivity of Gd‐EOB‐MRI for diagnostic criteria 1, 2, 3, and 4 was 63.4%, 52.1%, 22.5%, and 69.0%.

Conclusion:

The maximum sensitivity of Gd‐EOB‐MRI for HCC was only 69.0% even when diagnostic criteria that included all previously reported HCC patterns were adopted. J. Magn. Reson. Imaging 2013;37:684—691. © 2012 Wiley Perioidicals, Inc.     

Interstitial MR lymphography with a conventional extracellular gadolinium-based agent: assessment in rabbits

PURPOSE: To evaluate gadoterate meglumine as a contrast agent for interstitial magnetic resonance (MR) lymphography in combination with an adapted fast three-dimensional (3D) MR sequence. MATERIALS AND METHODS: In 12 New Zealand White rabbits, 0.5 mL of undiluted gadoterate meglumine was injected subcutaneously into the dorsal foot pad (n = 9) or the foreleg (n = 3) bilaterally. Immediately after administration, a slight massage was performed at the injection site. Imaging was performed with a 3D spoiled gradient-recalled echo sequence (6.7/1.6 [repetition time msec/echo time msec]; field of view, 28.0 x 19.6; two signals acquired) similar to that used for 3D MR angiography. Thus, 3D maximum intensity projection images could be obtained. Images were obtained before injection and 5, 15, 30, 60, and 120 minutes after injection. RESULTS: In the hind legs, as many as four successive lymph node groups were depicted with maximum enhancement after 5-15 minutes for the popliteal lymph node group, 15-30 minutes for the inguinal lymph group, and 30-60 minutes for the iliac-paraaortal lymph node group; the iliac-paraaortal lymph node group was not consistently enhanced. In the forelegs, four successive lymph node groups, including axillary and mediastinal lymph node groups, showed marked gadolinium uptake, with maximum enhancement 5-15 minutes after injection. CONCLUSION: As a widely tested positive-enhancing T1 contrast agent with favorable safety features, gadoterate meglumine allows the depiction of three to four successive lymph node groups early after subcutaneous injection. With the sequence used, 3D MR lymphangiograms can be obtained.