Dynamic gadopentetate dimeglumine-enhanced MR imaging of hepatocellular carcinoma

Nineteen patients with 28 histologically proven hepatocellular carcinomas (HCCs) were examined using T1- and T2-weighted spin-echo sequences and dynamic gadopentetate dimeglumine-enhanced magnetic resonance imaging (MRI) performed by fast T1-weighted gradient-echo sequence (100/5/80°) which was performed before and repeatedly (12 sets of images) after intravenous bolus injection of gadopentetate dimeglumine (Gd-DTPA) over a period of 10 min. Enhancement of HCC was heterogeneous in 24 lesions (85.7%). Intra-lesional non-enhancing areas were seen in 18 cases (64%). A late-enhancing pseudocapsule was seen in 12 lesions (42.9%). In addition, two groups were distinguished in the examined HCCs: 16 lesions (57.1%) showed stronger enhancement compared to liver parenchyma with maximum positive lesion-to-liver contrast on the 15-s images, while 12 lesions (42.9%) had an enhancement less than normal liver with a maximum negative contrast on the 15-s images. We conclude that the morphologic features most frequently encountered in HCC on dynamic Gd-DTPA-enhanced MRI are inhomogeneity of enhancement, intra-lesional non-enhancing areas, and relatively late enhancement of a pseudocapsule. Taking the degree of enhancement to be representative of the degree of vascularity, we also conclude that HCC can appear either hypervascular or hypovascular in the early phase of the dynamic study. Correspondence to: B. Hamm     

Spin-echo and dynamic gadoliniumenhanced flash MR imaging of hepatocellular carcinoma: Correlation with histopathologic findings

Evaluation of histologic subtype and degree of differentiation in hepatocellular carcinoma (HCC) is essential because it affects patient prognosis and treatment planning. To evaluate the histologic subtype of HCC with magnetic resonance (MR) imaging, conventional spin-echo and dynamic studies were correlated with histopathologic and angiographic findings in 72 HCCs. Dynamic MR imaging was performed with the fast low-angle shot (FLASH) technique after administration of gadopentetate dimeglumine. There was considerable overlap in signal intensity between various tumor grades on both T1- and T2-weighted images. On dynamic MR images, the peak contrast enhancement ratio correlated with tumor grade (well-differentiated, 29.5 ± 24.7; moderately differentiated, 63.5 ± 24.1; poorly differentiated, 86.9 ± 26.4) or degree of dilatation of the sinusoidlike vascular space between tumor cells. The maximum contrast-to-noise ratio in tumor (relative to surrounding liver) was achieved within 60 seconds in 45 HCCs (mostly of the trabecular or pseudoglandular type). Enhancement was slight or minimal in 17 tumors (mostly small, well-differentiated tumors). In 10 tumors, the degree of enhancement increased with time, with maximum enhancement in the delayed phase (most frequently in scirrhous HCC). These dynamic patterns correlated with angiographic findings. These data indicate that the degree and pattern of enhancement on dynamic MR images reflect tumor differentiation and architecture of HCC.     

Detection of hepatocellular carcinoma: comparison of Gd-DTPA- and ferumoxides-enhanced MR imaging

The aim was to compare the diagnostic performance of dynamic Gd-DTPA- and ferumoxides-enhanced MRI for hepatocellular carcinoma (HCC). Twenty-five patients with chronic hepatitis or liver cirrhosis underwent both dynamic gadopentetate- and ferumoxides-enhanced MRI studies of the liver for HCC detection on the same day. MR data of both studies were retrospectively and independently analyzed. Two observers determined in consensus the grade of diffuse fibrotic liver changes (mild, moderate or severe) and the number of focal lesions. HCCs were confirmed by histology (n=22) and/or follow-up studies for at least six months (n=64). Differences in results obtained from both MR data sets were tested for significance with the McNemars test (p<0.05). Ferumoxides-enhanced MR images detected 84 of 99 hepatic lesions, including 82 of 86 HCCs and 2 false positive, nonmalignant lesions, while Gd-DTPA-enhanced MR images detected 92 of 99 hepatic lesions, including 81 of 86 HCCs and 11 false positive, nonmalignant lesions. Sensitivity of MRI for detection of HCCs was not significantly different between ferumoxides-enhanced (95.3%; p>0.05) and Gd-DTPA-enhanced scans (94.2%). Gd-DTPA- and ferumoxides-enhanced MRI perform equally well for HCC detection. The majority of small hypervascular hepatic lesions, detected on dynamic Gd-DTPA-enhanced MRI but not on ferumoxides-enhanced MRI, represent no HCCs.     

The dynamic magnetic resonance study of focal liver lesions by FLASH sequences with bolus intravenous gadolinium-DTPA]

Thirty-five patients with hepatic hemangioma (n = 12), metastasis (n = 10), hepatocellular carcinoma (HCC) (n = 10) and focal nodular hyperplasia (n = 3) were examined with the fast low-angle shot (FLASH) technique and an intravenous bolus injection of Gd-DTPA. In order to differentiate the lesions, the following criteria were used: a) pre Gd-DTPA intensity of lesions; b) post Gd-DTPA patterns of contrast enhancement. On the basis of these criteria, an unquestionable differential diagnosis could be made. Hemangiomas were characterized by an hypointense mass before Gd-DTPA, by peripheral contrast enhancement and by subsequent continuous hyperintense fill-in; thus, hemangiomas were visualized as hyperintense lesion during the late phase. Before contrast administration hypovascular metastases appeared as hypointense; they were characterized by delayed uptake of contrast agent. HCCs were hyperintense lesions before contrast administrations; then, quick contrast enhancement and rapid decrease in signal intensity were observed with visualization of a hyperintense ring due to the capsule. Finally, focal nodular hyperplasia appeared isointense or hypointense relative to normal liver on precontrast scans; the lesions were enhanced transiently with subsequent quick dismission of contrast agent. This initial experience suggests dynamic contrast-enhanced MR imaging as an effective method to improve the differential diagnosis among hepatic tumors when precontrast T2-weighted images are equivocal.     

Gadobenate dimeglumine-enhanced liver MR imaging: value of dynamic and delayed imaging for the characterization and detection of focal liver lesions

The aim of this study was to determine the value of delayed-phase imaging (DPI) of gadobenate dimeglumine (Gd-BOPTA)-enhanced MR imaging for the evaluation of focal hepatic tumors compared with precontrast imaging and early dynamic phase imaging. The MR images were obtained in 48 patients with 98 focal hepatic tumors. Three-dimensional gradient-echo (GRE) imaging obtained before and 30, 60, and 1 h after administration of 0.1 mmol/kg of gadobenate dimeglumine. Each image set was analyzed qualitatively (lesion detection, conspicuity, delineation, and enhancement pattern on DPI) and quantitatively [signal-to-noise ratio (SNR), tumor–liver contrast-to-noise ratio (CNR)]. Improved lesion-to-liver contrast during the dynamic phase imaging was observed compared with precontrast images. The DPI showed a homogeneous enhancement of liver parenchyma and distinctive enhancement features of focal liver lesions: metastases (85%) showed a target shaped enhancement, and hepatocellular carcinomas (HCCs) showed an inhomogeneous (58%) or homogeneous enhancement (21%). The DPI showed better performance for the detection of metastases than other images by increasing lesion delineation (p<0.05). The absolute CNR of metastasis measured from periphery of the tumors on DPI was greater than precontrast and arterial phase imaging (p<0.05). The Gd-BOPTA during both dynamic and delayed phases provides valuable information for the characterization of focal liver lesions, and furthermore, Gd-BOPTA-enhanced DPI contributed to the improved detection of liver metastasis compared to precontrast and early dynamic imaging.     

Small hepatocellular carcinoma and cavernous hemangioma: differentiation with dynamic FLASH MR imaging with Gd-DTPA

Forty patients with hepatocellular carcinoma (HCC) (n = 22) or cavernous hemangioma (diameter, 3 cm or less) (n = 18) were examined with serial magnetic resonance (MR) imaging at 1.5 T with the fast low-angle shot (FLASH) technique and an intravenously administered bolus injection of 0.05 mmol/kg Gd-DTPA. Two images per minute were obtained for 5 minutes, and one per minute thereafter until about 10 minutes. Dynamic MR studies revealed five criteria for differentiating these tumors. With HCC there was a hyperintense mass before contrast material enhancement (32%), peak contrast enhancement at about 10 seconds after injection (55%), slight to moderate peak contrast enhancement (73%), absent or minimal delayed enhancement (100%), and, at morphologic study, a capsule or nodules-in-nodule appearance (59%). With hemangioma there was a hypointense mass before contrast enhancement (72%), peak contrast enhancement more than 2 minutes after injection (72%), marked peak contrast enhancement (83%), moderate to marked delayed enhancement (100%), and, at morphologic study, spreading phenomenon (39%). Seventy-seven percent of HCCs and 83% of hemangiomas satisfied three or more criteria and thus could be differentiated from each other with certainty.     

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.     

Prolonged positive contrast enhancement with Gd-EOB-DTPA in experimental liver tumors: Potential value in tissue characterization

To evaluate the potential of the hepatobiliary magnetic resonance (MR) imaging contrast agent gadolinium EOB-DTPA (ethoxybenzyl diethylenetria-minepentaacetic acid) for the characterization of hepatic tumors, 79 primary and six implanted hepatomas in 38 rats were studied. MR imaging findings after administration of Gd-DTPA (0.3 mmol/kg) and Gd-EOB-DTPA (30 μmol/kg) were correlated with microangiographic and histologic findings. Gd-EOB-DTPA produced a strong liver enhancement, which caused prompt negative contrast enhancement (CE) in all implanted hepatomas and in 77 of 79 primary hepatomas. A positive CE that lasted up to 2 hours was found in two of 79 primary hepatomas, both of which were highly differentiated (grade I) hepatocellular carcinomas (HCCs). The rest were moderately differentiated to undifferentiated HCCs (grades II-IV). Rim enhancement, which corresponded histologically to peritumoral malignant infiltration sequestering normal hepatocytes, was seen around all implanted and some primary hepatomas. Positive tumor CE after administration of Gd-EOB-DTPA in this study is much less frequent but much more specific in comparison with the results of previous studies with manganese-DPDP (N, N′-dipyridoxylethylenediamine-N,N′-diacetate 5,5′-bis[phosphate]). These findings may help further discriminate hepatic tumors.     

Delayed MR imaging of hepatocellular carcinoma enhanced by gadobenate dimeglumine (Gd-BOPTA).

The purpose of this study was to determine the efficacy of gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance (MR) imaging for evaluation of hepatocellular carcinoma HCC. MR images were obtained in 14 patients with 31 HCC nodules as a part of a phase III clinical trial. T1- and T2-weighted images were obtained before and after iv administration of 0.1 mmol/kg of Gd-BOPTA. Two blinded readers evaluated pre- and delayed postcontrast images separately for detection of tumor nodules. Quantitative measurements of signal-to-noise (SNR) and tumor/liver contrast-to-noise (CNR) ratios were also performed. A signal/intensity ratio was calculated. Tumor enhancement was correlated with histologic findings. Consensus agreement of precontrast T1- and T2-weighted images revealed 23/31 HCC nodules in 14 patients; postcontrast T1-weighted images demonstrated 24/31 HCC nodules in the same number of patients. Combining both pre- and postcontrast images, 27/31 lesions were detected. Four patients had four well-differentiated HCC nodules detected only on postcontrast images, while three well-differentiated lesions in two patients were only seen on precontrast images. Quantitative evaluation showed an SNR ratio increase in both liver parenchyma and HCC nodules, as well as a significant increase in the absolute CNR ratio on postcontrast T1-weighted gradient-recalled images (P < 0.05). Well-differentiated HCC lesions showed a greater enhancement than poorly differentiated HCC lesions.     

MR characterisation of dysplastic nodules and hepatocarcinoma in the cirrhotic liver with hepatospecific superparamagnetic contrast agents: pathological correlation in explanted livers

Purpose

The authors sought to evaluate the potential of magnetic resonance (MR) imaging with superparamagnetic iron oxide (SPIO) contrast material for identifying, characterising and differentiating dysplastic nodules (DN) and hepatocellular carcinoma (HCC) in the cirrhotic liver by correlating the results with pathological findings on the explanted liver.

Material and methods

MR imaging was used to study the liver of 400 cirrhotic patients awaiting liver transplantation, 31 of whom were selected to receive a liver. Of these 31 patients, we included in the study 22 patients (mean age 53 years; range 46–57 years) who underwent liver transplantation within 12–24 h after MR examination. Patients were studied with a 1.5-T device, and scans were acquired before and after the administration of paramagnetic contrast material. For every lesion, we recorded signal intensity on unenhanced baseline T1- and T2-weighted images and enhancement pattern after SPIO administration. Histological examination of the entire liver provided the definitive diagnosis of the lesions.

Results

Histological examination identified 59 lesions: 14 HCC, 4 HCC-DN, 39 DN, and 2 cystoadenomas. Among the 14 HCC, three were well differentiated, eight were moderately differentiated and three were poorly differentiated. Of the 39 DN, 28 were low-grade and 11 high-grade lesions. Unenhanced baseline MR imaging correctly identified and characterised 20 lesions, equal to 33.90% of all lesions: 6 HCC, 12 DN and 2 DN with a subfocus of HCC. SPIO-enhanced MR imaging showed greater sensitivity detecting and characterising 45 lesions, equal to 76.27% of all lesions identified at histology: 14 HCC, 27 DN and 4 DN with subfocus of HCC. SPIO administration improved the sensitivity of MR imaging in lesion detection and characterisation by 42.37%. False negative results with SPIO-enhanced MR imaging occurred in 12 DN (31%), which histological examination revealed to be low-grade DN with a diameter <1 cm.

Conclusions

SPIO-enhanced MR imaging proved to be of value in detecting and characterising lesions in the cirrhotic liver, allowing differentiation of DN from HCC and providing an early diagnosis of neoplastic degeneration of DN.     

The value of gadobenate dimeglumine-enhanced delayed phase MR imaging for characterization of hepatocellular nodules in the cirrhotic liver

OBJECTIVES: To evaluate the value of 1-hour delayed phase imaging (DPI) of gadobenate dimeglumine (Gd-BOPTA)-enhanced MR imaging for the characterization of hepatocellular carcinoma (HCC) and dysplastic nodule (DN) in patients with cirrhosis. MATERIALS AND METHODS: A total of 37 patients with 42 HCCs and 13 DNs were included in this study and all lesions were histopathologically confirmed except for 15 HCCs. T1-weighted 3-dimensional gradient-echo images were acquired before, immediately after (30, 60, 180 s), and 1 hour after bolus injection of gadobenate dimeglumine at a dose of 0.1 mmol/kg. The lesions were classified as isointense, hypointense, or hyperintense compared with the surrounding liver parenchyma on DPI for qualitative assessment. We performed quantitative analyses of the contrast-to-noise ratio (CNR) and of the relative contrast enhancement of the lesion on the DPI. RESULTS: In the qualitative analysis, among 42 HCCs, 30 (71.4%) were hypointense on DPI, and 10 (23.8%) and 2 (4.8%) were isointense and hyperintense, respectively; only 1 of 13 DNs (7.7%) was hypointense and 10 (76.9%) and 2 (15.4%) were isointense and hyperintense, respectively. In contrast, 25 HCCs (71.4%) of 35 hypervascular HCCs were hypointense on DPI, and no hypervascular DN (0/7) was hypointense with statistical significance (P = 0.0007). When we considered the hypointensity of the hepatic lesions on delayed phase as a sign of HCC in cirrhotic liver, our results gave a sensitivity of 71.4% and a specificity of 91.7%. In the quantitative analysis, the mean CNR of the HCCs and the DNs on the 1-hour DPI was -6.32 +/- 6.27 and -0.07 +/- 3.28, respectively; the difference between the HCCs and the DNs was significant (P < 0.05). CONCLUSIONS: Delayed gadobenate dimeglumine-enhanced MR imaging allows improved characterization of HCC in cirrhotic liver. The relative hypointensity to adjacent normal liver parenchyma is a reliable predictor that this lesion favors HCC rather than DN in cirrhotic liver.     

Evaluation of hepatocellular carcinoma using SonoVue,a second generation ultrasound contrast agent: correlation with cellular differentiation

The appearance of hepatocellular carcinoma (HCC) with contrast-enhanced ultrasound (CEUS) in the vascular phase is described and evaluated as to whether the enhancement pattern correlates with the degree of cellular differentiation. One hundred four HCCs were prospectively evaluated with CEUS using coherent-contrast imaging (CCI) and SonoVue with a low mechanical index (<0.2). The enhancement of HCCs in the vascular phase was analyzed according to the degree of pathological differentiation obtained by fine-needle biopsy. In the arterial phase, all HCCs except for four well differentiated ones (96.2%) showed enhancement (P<0.05). Histological differentiation of hypoechoic lesions in the early portal phase (7 HCCs; 16%) significantly differed from hyperechoic (1 HCC; 1%) or isoechoic lesions (87 HCCs; 83.6%) (P<0.05), with a significant probability of a worse differentiation in hypoechoic lesions. Histological differentiation of isoechoic lesions in the late phase (30 HCCs; 28.8%) significantly differed from hypoechoic lesions (74 HCCs; 71.2%) (P<0.05), with a significant probability of a better differentiation in isoechoic lesions. CEUS using CCI and SonoVue revealed enhancement in the arterial phase in >95% of HCCs, with a few well-differentiated cases not being diagnosed due to the absence of enhancement. Echogenicity in the portal and late phases correlated with cellular differentiation.     

Evaluation of [Gd(Bz-TTDA)]2- as a potential contrast agent in MR imaging of the hepatobiliary system: an animal study

PURPOSE: To evaluate the potential of a new lipophilic paramagnetic complex [Gd(Bz-TTDA)]2- [(4s)-4-benzyl-3,6,10-tri(carboxymethyl)-3,6,10-triazadodecandioic acid]2- designed for use as a hepatobiliary MR contrast agent. MATERIALS AND METHODS: MR imaging studies for normal and hepatocellular carcinoma (HCC) rat models were performed using a 1.5-T scanner. Sequential multislice T1-weighted turbo field echo (TFE) (TR/TE/flip angle: 15 msec/6.1 msec/25 degrees) coronal images of normal rats were obtained before and after intravenous injections of 0.1 mmol/kg [Gd(Bz-TTDA)]2- in study groups (N = 12) or 0.1 mmol/kg gadopentate dimeglumine (Gd-DTPA)2- in control groups (N = 12). Similar protocols of MR imaging with additional T2-weighted images were used for the rats with implanted HCC in both study and control groups (N = 12, in each group). MR images were analyzed to evaluate the time-enhancement change (% increase of signal-to-noise ratio [SI/N]) in normal liver, renal cortex, renal medulla, and tumors. The liver-lesion contrast-to-noise ratios (CNR) were also evaluated in study and control groups. The rats were killed immediately after the last MR scan to undergo autopsy and histopathologic observation. The acute toxicity test (medial lethal dose, LD50) in mice was also done. RESULTS: The liver enhancement in normal rats reached a plateau 5-50 minutes after injection of [Gd(Bz-TTDA)]2-, maintained for three hours, then gradually declined. Intensity of enhancement in liver, renal cortex, and medulla after injection of [Gd(Bz-TTDA)]2- was significantly higher than with Gd-DTPA. The efficacy of tumor characterization with injection of [Gd(Bz-TTDA)]2- was similar to that of Gd-DTPA at the early dynamic phase of the contrast study. However, the liver-lesion CNRs were significantly higher in the study group in the later phase, when tumor enhancement decreased and liver enhancement persisted. The dose of LD50 in acute toxicity test of [Gd(Bz-TTDA)]2- in mice was 7.5 mmol/kg. CONCLUSION: The preliminary results in this animal study indicated that [Gd(Bz-TTDA)]2- has the potential of becoming a reliable liver MR contrast agent.     

Characterization of Focal Liver Lesions with Superparamagnetic Iron Oxide-Enhanced MR Imaging: Value of Distributional Phase T1-Weighted Imaging

Objective

To determine the potential value of distributional-phase T1-weighted ferumoxides-enhanced magnetic resonance (MR) imaging for tissue characterization of focal liver lesions.

Materials and Methods

Ferumoxides-enhanced MR imaging was performed using a 1.5-T system in 46 patients referred for evaluation of known or suspected hepatic malignancies. Seventy-three focal liver lesions (30 hepatocellular carcinomas [HCC], 12 metastases, 15 cysts, 13 hemangiomas, and three cholangiocarcinomas) were evaluated. MR imaging included T1-weighted double-echo gradient-echo (TR/TE: 150/4.2 and 2.1 msec), T2*-weighted gradient-echo (TR/TE: 180/12 msec), and T2-weighted turbo spin-echo MR imaging at 1.5 T before and after intravenous administration of ferumoxides (15 mmol/kg body weight). Postcontrast T1-weighted imaging was performed within eight minutes of infusion of the contrast medium (distributional phase). Both qualitative and quantitative analysis was performed.

Results

During the distributional phase after infusion of ferumoxides, unique enhancement patterns of focal liver lesions were observed for hemangiomas, metastases, and hepatocellular carcinomas. On T1-weighted GRE images obtained during the distributional phase, hemangiomas showed a typical positive enhancement pattern of increased signal; metastases showed ring enhancement; and hepatocellar carcinomas showed slight enhancement. Quantitatively, the signal-to-noise ratio of hemangiomas was much higher than that of other tumors (p < .05) and was similar to that of intrahepatic vessels. This finding permitted more effective differentiation between hemangiomas and other malignant tumors.

Conclusion

T1-weighted double-echo FLASH images obtained soon after the infusion of ferumoxides, show characteristic enhancement patterns and improved the differentiation of focal liver lesions.     

Gadobenate dimeglumine-enhanced liver MR imaging in cirrhotic patients: quantitative and qualitative comparison of 1-hour and 3-hour delayed images

Purpose:

To compare the image quality and diagnostic performance of 1‐ and 3‐h delayed‐phase MR images (DPIs) after gadobenate dimeglumine injection in detecting small hepatocellular carcinomas (HCCs) in cirrhotic patients.

Materials and Methods:

Relative enhancement of the liver (RE_liver) and HCC (RE_HCC) and liver‐to‐lesion contrast‐to‐noise ratio (CNR) of HCC were measured quantitatively on 1‐ and 3‐h DPIs in 65 patients with 88 HCCs. For qualitative analysis, two radiologists independently evaluated three image sets in 19 patients with 25 HCCs ≤2 cm and in 16 controls without HCCs: conventional liver MR without DPI (set A), adding 1‐h DPI (set B), and adding 3‐h DPI (set C), using a 5‐point scale for diagnosing small HCCs. Diagnostic performance for small HCCs was analyzed using the alternative free‐response receiver operating characteristic method.

Results:

Mean RE_liver (P = 0.013) and RE_HCC (P < 0.001) were significantly higher on 1‐h than on 3‐h DPI, whereas CNR was significantly higher on 3‐h than on 1‐h DPI (P = 0.001). Observer‐averaged figure of merit (FOM) was significantly higher for set C than for set A (0.942 versus 0.883; P = 0.013).

Conclusion:

In cirrhotic patients, 3‐h DPI provides a higher liver‐to‐lesion contrast and a better diagnostic performance for small HCCs than 1‐h DPI. J. Magn. Reson. Imaging 2011;33:889–897. © 2011 Wiley‐Liss, Inc.     

Gadoxetic acid-enhanced magnetic resonance imaging characteristics of hepatocellular carcinoma occurring in liver transplants

Objectives

Characteristics of hepatocellular carcinoma (HCC) on magnetic resonance (MR) images were compared in patients who did or did not undergo liver transplantation (LT), and we evaluated the relationship of these findings with overall survival (OS) and time-to-tumour recurrence (TTR) after transplantation.

Methods

The enhancement pattern of gadoxetic acid-enhanced MR images of 25 patients with recurrent HCCs (LT group) and 25 surgically confirmed HCC patients in the non-transplanted (control) group were compared. Typical enhancement was defined as 1) arterial enhancement and delayed wash-out and 2) absence of typical features of cholangiocarcinoma consisting of arterial rim enhancement and target appearance on hepatobiliary phase images. OS and TTR were analyzed in the LT group according to these patterns using the log-rank test.

Results

HCCs in the LT group significantly more often had an atypical enhancement pattern (16/25, 64.0%) than those in the control group (5/25, 20.0%; p = 0.004). However, OS and TTR did not differ significantly according to these enhancement patterns of recurrent HCC (p > 0.05).

Conclusion

Although enhancement patterns of recurrent HCC in transplanted liver did not affect OS and TTR, these HCCs that arise after LT frequently revealed atypical enhancement on gadoxetic acid-enhanced MR imaging.

Key Points

? Recurrent HCCs after LT showed atypical enhancement on gadoxetic acid-enhanced MRI.?They showed absence of delayed wash-out or cholangiocarinoma-like features.? Enhancement patterns of recurrent HCCs did not affect OS and TTR.

     

Magnetic resonance imaging (MRI) of primary liver cancer--MRI-pathologic correlation

In seven primary liver cancers (HCC 5, CCC 1, mixed 1), MR images (0.35 Tesla super-conducting) were compared with macroscopic appearances, and relaxation times (T1 and T2) with microscopic characteristics. MRI was able to reveal the gross appearance of five nodular lesions, but did not reveal one diffuse HCC and one nodular HCC with marked extracapsular extension. T2-weighted SE images could not demonstrate fibrous capsules around the tumor in four nodular HCCs. The T1 and T2 values of the tumors were longer than those of the surrounding liver parenchyma, and the T1 elongation corresponded roughly to the degree of necrosis and fibrosis within the tumors.     

Marginal erosive discovertebral ”Romanus” lesions in ankylosing spondylitis demonstrated by contrast enhanced Gd-DTPA magnetic resonance imaging

Objective. To assess the value of Gd-DTPA magnetic resonance (MR) imaging in the demonstration of marginal destructive discovertebral Romanus lesions in ankylosing spondylitis. Design and patients. A prospective study of Gd-DTPA MR imaging was performed in 39 patients with a clinical diagnosis of ankylosing spondylitis and typical Romanus lesions seen on radiographs of the thoracolumbar spine. MR morphological appearances and signal intensity changes at the discovertebral junctions were analysed and compared with the radiographic findings. Results. Ninety-nine discovertebral junctions with Romanus lesions showed low signal intensity on T1-weighted and high signal on T2-weighted and T1-weighted postcontrast images at the vertebral corners consistent with oedematous hyperaemic inflammatory tissue. There were nine discovertebral junctions with similar MR findings but normal radiographs. Fifty-three discovertebral junctions showed syndesmophyte formation with increased signal intensity on both T1- and T2-weighted images with no contrast enhancement. Sixty-five discovertebral junctions showed a mixture of radiographic features and varied high and low signal changes at the vertebral rim on MR imaging with rims of enhancement in the vertebral body following contrast administration. Conclusion. Gd-DTPA MR imaging demonstrates a variable signal pattern and degree of contrast enhancement which may reflect the evolutionary stages of discovertebral enthesitis in ankylosing spondylitis. MR imaging may identify early erosive changes in radiographically normal vertebra. The role of MR imaging needs further investigation. Received: 6 April 1998 Revision requested: 7 May 1998 Revision received: 26 October 1999 Accepted: 27 October 1999     

Diagnosis of small hepatocellular carcinoma: correlation of MR imaging and tumor histologic studies

Magnetic resonance (MR) images of the liver were used to study 43 patients with relatively small hepatocellular carcinomas (HCCs) and 36 with other hepatic mass lesions. In 27 HCC patients, histologic findings were available. All focal lesions detectable by CT without contrast media were delineated with greater contrast by MR imaging. The rate of detection depended on tumor size, being 97.5% for HCCs greater than 2 cm in the longest axis and 33.3% for those less than 2 cm. MR imaging demonstrated the ring sign characteristic of encapsulated HCC twice as frequently as CT scans. Inversion recovery (IR) images depicted the internal structure of the HCC better than T2-weighted spin-echo images. Lesions were classified into four patterns of intensity: low, iso, high, and mixed. The latter three were relatively characteristic of HCC and related closely with steatosis of cancer tissue. HCCs with fibrosis tended to have long T1 values; those with steatosis had short T1 values. T1 and T2 relaxation times were useful in the differential diagnosis.     

Preoperative detection of hepatocellular carcinoma: comparison of combined contrast-enhanced MR imaging and combined CT during arterial portography and CT hepatic arteriography

The aim of this study was to compare Gd-DTPA-enhanced dynamic MR images, superparamagnetic iron oxide (SPIO)-enhanced MR images, combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images, vs combined CT arterial portography (CTAP) and CT hepatic arteriography (CTHA), in the detection of hepatocellular carcinoma (HCC) using receiver operating characteristic (ROC) analysis. Twenty-four patients with 38 nodular HCCs (5–60 mm, mean 23.0 mm) were retrospectively analyzed. Image reviews were conducted on a liver segment-by-segment basis. A total of 192 segments, including 36 segments with 38 HCC, were reviewed independently by three radiologists. Each radiologist read four sets of images (set 1, unenhanced and Gd-DTPA-enhanced dynamic MR images; set 2, unenhanced and SPIO-enhanced MR images; set 3, combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images; set 4, combined CTAP and CTHA). To minimize any possible learning bias, the reviewing order was randomized and the reviewing procedure was performed in four sessions at 2-week intervals. The diagnostic accuracy (A_z values) for HCCs of combined CTAP and CTHA, combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images, Gd-DTPA-enhanced dynamic MR images, and SPIO-enhanced MR images for all observers were 0.934, 0.963, 0.878, and 0.869, respectively. The diagnostic accuracy of combined CTAP and CTHA and combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images was significantly higher than Gd-DTPA-enhanced dynamic MR images or SPIO-enhanced MR images (p<0.005). The mean specificity of combined CTAP and CTHA (93%) and combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images (95%) was significantly higher than Gd-DTPA-enhanced dynamic MR images (87%) or SPIO-enhanced MR images (88%; p<0.05). Combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images may obviate the need for more invasive combined CTAP and CTHA for the preoperative evaluation of patients with HCC.