Transarterial chemoembolization with miriplatin-lipiodol emulsion for neuroendocrine metastases of the liver

Miriplatin, a cisplatin derivative with a high affinity for iodized oil, is a novel chemotherapeutic agent designed for use in the transarterial treatment of hepatocellular carcinoma. This case report describes our experience with transarterial chemoembolization (TACE) using miriplatin in 2 patients with neuroendocrine liver metastases. A 38-year-old man with multiple neuroendocrine liver metastases was treated by whole liver chemoembolization, and a 35-year-old woman with a single hepatic lesion was treated by superselective chemoembolization. No serious adverse events were noted during the interventional procedures, or during the observation period of 3 mo in either patient. Sufficient iodized oil uptake was observed in the hypervascular lesions on the unenhanced computed tomography (CT) at 7 d after the procedure. Contrast-enhanced CT obtained at 3 mo after chemoembolization revealed that all hepatic lesions were substantially reduced in size irrespective of tumor vascularity or degree of cystic degeneration, although iodized oil accumulation was only marginal for lesions with cystic degeneration. Thus, TACE with miriplatin can be a safe and effective therapeutic option for the treatment of neuroendocrine metastases of the liver.     

肝转移瘤高场MRI诊断

目的:探讨高场MRI在肝转移瘤(HMs)中的检出、诊断与鉴别诊断价值。方法:收集经临床、影像证实的HMs 43例,所有病例均进行高场MRI平扫和动脉期、门脉期、延迟期扫描,其中23例尚做螺旋CT平扫、动脉期、门脉期扫描,分析记录HMs螺旋CT、高场MRI平扫及多期增强扫描特征。结果:共计174枚瘤灶在MRI平扫上呈长T2长T1信号,动脉期122枚瘤灶不强化,门脉期174枚瘤灶均呈环状强化,延迟期108枚瘤灶呈向心性充填;23例79枚瘤灶螺旋CT平扫均呈低密度,动脉期49枚瘤灶不强化,30枚呈环状强化,门脉期73枚呈环状强化,4枚呈向心性充填;43例HMs高场MRI均准确诊断,螺旋CT漏检2例,误诊7例。结论:高场MRI对HMs的检出、诊断与鉴别诊断具重要价值,可作为HMs的首选检查方法。     

Fluid-fluid level in hepatic metastases: a characteristic sign of metastases of neuroendocrine origin

Objectives

The aim of this study is to determine MRI characteristics which indicate liver metastases of neuroendocrine tumors (NET) rather than metastases of other origin (non-NET).

Methods

Sixty-nine patients with histopathologically proven liver metastases from NET and 69 patients with known liver metastases of other origin underwent MRI of the liver using a 1.5 T MR-scanner. Two board certified radiologists assessed presence of fluid–fluid-levels, number and distribution pattern, signal intensity (SI) characteristics, lesion homogeneity, presence of central necrosis and intratumoral hemorrhage in T2w and T1w non-contrast imaging. A multivariate logistic regression analysis was performed to determine the independent association of image findings and occurrence of NET.

Results

Fluid–fluid-levels were identified in 19/69 of patients with NET-metastases, and in none of the patients in the control group (p < 0.0001). Hyperintense SI in T1w imaging, markedly hyperintense SI in T2w imaging, a disseminated distribution pattern and intratumoral hemorrhage were indicative of NET metastases (p < 0.05). After statistical adjustment for all significant MRI findings, fluid–fluid-levels (OR: 17.6, 95% CI: 1.9–166.5), strongly hyperintense SI in T2w (OR: 4.7, 95% CI: 1.8–12.7) and a disseminated distribution pattern (OR: 2.9, 95% CI: 1.1–7.4) were independent predictors for NET metastases.

Conclusions

The presence of fluid–fluid-levels is highly indicative of NET liver metastases and can be used as an independent predictor to distinguish them from metastases of other origin.     

Therapy monitoring of skeletal metastases with whole‐body diffusion MRI

Current methods of assessing tumor response at skeletal sites with metastatic disease use a combination of imaging tests, serum and urine biochemical markers, and symptoms assessment. These methods do not always enable the positive assessment of therapeutic benefit to be made but instead provide an evaluation of progression, which then guides therapy decisions in the clinic. Functional imaging techniques such as whole‐body diffusion magnetic resonance imaging (MRI) when combined with anatomic imaging and other emerging “wet” biomarkers can improve the classification of therapy response in patients with metastatic bone disease. A range of imaging findings can be seen in the clinic depending on the type of therapy and duration of treatment. Successful response to systemic therapy is usually depicted by reductions in signal intensity accompanied by apparent diffusion coefficient (ADC) increases. Rarer patterns of successful treatment include no changes in signal intensity accompanying increases in ADC values (T2 shine‐through pattern) or reductions in signal intensity without ADC value changes. Progressive disease results in increases in extent/intensity of disease on high b‐value images with variable ADC changes. Diffusion MRI therapy response criteria need to be developed and tested in prospective studies in order to address current, unmet clinical and pharmaceutical needs for reliable measures of tumor response in metastatic bone disease. J. Magn. Reson. Imaging 2014;39:1049–1078 . © 2014 Wiley Periodicals, Inc .     

Evaluation of radiological prognostic factors of hepatic metastases in patients with non-functional pancreatic neuroendocrine tumors

Purpose

There are different therapeutic options in non-functional well to moderately differentiated (G1 and G2) pancreatic neuroendocrine tumors (pNET) with unresectable hepatic metastases including systemic chemotherapy and novel molecular targeted therapies. Treatment with somatostatin analogs (SSA) as antiproliferative agents is optional. At initial diagnosis watchful waiting until tumor progression is a well-established approach. Goal of this study was to evaluate imaging features as potential prognostic factors predicting early tumor progression in order to select patients that might benefit from an earlier initiation of medical treatment.

Patients and methods

In 44 patients we correlated tumor grade, chromogranin A (CgA) levels, treatment with SSA and imaging features of hepatic metastases on contrast-enhanced multiphase CT and MR imaging with time to tumor progression (TTP) according to RECIST 1.0.

Results

In the total patient cohort none of the tested imaging features was found to be a statistically significant prognostic factor for TTP. Since treatment with SSA was associated with an increased TTP we also analyzed a subgroup of 30 patients not treated with SSA. In this subgroup of patients hypoenhancement of hepatic metastases during early contrast phases was found to be a negative prognostic factor for early tumor progression within 12 months (p = 0.039). The other evaluated parameters including hepatic tumor load, number of metastases, and presence of regressive morphological changes did not reveal significant results.

Conclusion

Hypovascularization of liver metastases from G1 and G2 pNET reflected by hypoenhancement during the early contrast phases seems to be associated with early tumor progression. In patients with hypoenhancing metastases repeated biopsy for reassessment of grading of these metastases, and early initiation of therapy should be considered.     

Small colorectal liver metastases: Detection with SPIO-enhanced MRI in comparison with gadobenate dimeglumine-enhanced MRI and CT imaging

The aim of this prospective study was to compare the diagnostic role of superparamagnetic iron oxide (SPIO)-enhanced liver magnetic resonance imaging (MRI) versus gadobenate dimeglumine (GbD)-enhanced MRI and computed tomography (CT) investigations for detection of small (less than 1 cm) colorectal liver metastases (LMs) of colorectal cancer. Seventy-eight LMs in 16 patients were evaluated with dynamic CT imaging, GbD-enhanced dynamic MR imaging and SPIO-enhanced MR imaging. Two radiologists were reviewed the LMs seperately. Agreement between the readers and three algorithms was analyzed. Differences between the lesion detection ratios of the methods were analyzed by two proportion z test. Sensitivity values of each modality were also calculated. Interobserver agreement values with kappa analysis were found to be the best for three modalities and kappa values were 0.866, 0.843, and 1.0 respectively. For all 78 LMs, SPIO-enhanced MRI detected all lesions (100% sensitivity). This sensitivity value was higher than GbD-enhanced MRI, and there was a significant difference (p < 0.05). GbD-enhanced MRI depicted 71 lesions and this modality could not detected 7 lesions (91% sensitivity). This modality had moderate sensitivity, and this value is greater than CT imaging, so there was a significant difference also (p < 0.05). Dynamic triphasic CT imaging detected 64 (R1) and 65 (R2) LMs. This modality had the lowest sensitivity (R1: 0.82, R2: 0.83 respectively). Only SPIO-enhanced MRI was able to detect all LMs less than 1 cm. LMs were the best detected with SPIO-enhanced MRI. We recommend SPIO-enhanced MRI to be the primary alternative modality especially for diagnosis of small colorectal LMs.     

Radio-frequency ablation of colorectal liver metastases in 167 patients

The objective of this paper is to report our results from a prospective study of 167 patients with colorectal liver metastases treated with radio-frequency ablation (RFA). Three hundred fifty-four treatments were performed in 167 patients, 99 males, mean age 57 years (34–87). The mean number of metastases was 4.1 (1–27). The mean maximum diameter was 3.9 cm (1–12). Fifty-one (31%) had stable/treated extra-hepatic disease. Treatments were performed under general anaesthesia using US and CT guidance and single or cluster water-cooled electrodes (Valleylab, Boulder, CO). All patients had been rejected for or had refused surgical resection. Eighty percent received chemotherapy. Survival data were stratified by tumour burden at the time of first RFA. The mean number of RFA treatments was 2.1 (1–7). During a mean follow-up of 17 months (0–89), 72 developed new liver metastases and 71 developed progressive extra-hepatic disease. There were 14/354 (4%) major local complications and 22/354 (6%) minor local complications. For patients with 5 metastases, maximum diameter 5 cm and no extra-hepatic disease, the 5-year survival from the time of diagnosis was 30% and from the time of first thermal ablation was 26%. Given that the 5-year survival for operable patients is a median of 32%, our 5-year survival of 30% is promising.     

Invited MRI of the liver

MRI of the liver is a powerful imaging modality for detection and characterization of liver pathology. MRI technology continues to evolve with developments in scanner hardware performance and refinements in imaging sequences, particularly in respect to fast imaging techniques, improving the quality of images that can be routinely achieved. Fast imaging techniques allow dynamic contrast-enhanced scanning to assist in lesion detection and characterization. An array of tissue-specific contrast agents are also becoming available; the clinical utility of some of these agents is yet to be fully established. An overview of scanning technique, contrast media, and the role of MRI in liver lesion detection and characterization is presented, with a review of the typical imaging characteristics of common focal and diffuse hepatic diseases. Where possible, emphasis has been placed on features that allow distinction between the various pathologic entities described.     

Intra-individual comparison of CAIPIRINHA VIBE technique with conventional VIBE sequences in contrast-enhanced MRI of focal liver lesions

PurposeTo evaluate the impact of controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) volume interpolated breath-hold examination (VIBE) magnetic resonance imaging (MRI) technique on image quality, reader confidence, and inter-observer agreement for the assessment of focal liver lesions in comparison with the standard VIBE approach.Material and methodsIn this IRB-approved intra-individual comparison study, abdominal arterial and portal-venous contrast-enhanced MRI studies were retrospectively analyzed in 38 patients with malignant liver lesions. Each patient underwent both CAIPIRINHA and conventional VIBE 3 T MRI within 3 months, showing stable disease. Images were evaluated using 5-point rating scales by two blinded radiologists with more than 20 and 5 years of experience in MRI, respectively. Readers scored dignity of liver lesions and assessed which liver segments were affected by malignancy (ranging from 1 = definitely benign/not affected to 5 = definitely malignant/affected by malignancy). Readers also rated overall image quality, sharpness of intrahepatic veins, and diagnostic confidence (ranging from 1 = poor to 5 = excellent).ResultsReviewers achieved a higher inter-observer reliability using CAIPIRINHA when they reported which liver segments were affected by malignancy compared to traditional VIBE series (κ = 0.62 and 0.54, respectively, p < 0.05). Similarly, CAIPIRINHA showed a slightly higher inter-rater agreement for the dignity of focal liver lesions versus the standard VIBE images (κ = 0.50 and 0.49, respectively, p < 0.05). CAIPIRINHA series also scored higher in comparison to standard VIBE sequences (mean scores: image quality, 4.2 and 3.5; sharpness of intrahepatic vessels, 3.8 and 3.2, respectively, p < 0.05) for both reviewers and allowed for higher subjective diagnostic confidence (ratings, 3.8 and 3.2, respectively, p < 0.05).ConclusionCompared to the standard VIBE approach, CAIPIRINHA VIBE technique provides improved image quality and sharpness of intrahepatic veins, as well as higher diagnostic confidence. Additionally, this technique allows for higher inter-observer agreement when reporting focal liver lesions for both dignity and allocation.     

Liver metastases of neuroendocrine carcinomas: interventional treatment via transarterial embolization, chemoembolization and thermal ablation

The aim of this review article is to provide a practical clinical guideline for indication, technical aspects, protocol guideline and strategies for the interventional treatment of liver metastases from neuroendocrine tumors and focusing on the results of various protocols of management. The response to therapy, in the published articles, is calculated on the basis of the following clinical parameters; including symptomatic response (SR), biologic response (BR), morphological response (MR), progress free survival (PFS), and survival periods (SP). Transarterial chemoembolization (TACE) has been associated with SR rates of 60-95%, BR of 50-90%, MR of 33-80%, SR of 20-80 months, and a 5-year survival of between 50% and 65%. PFS was also between 18 and 24 months. In the transarterial embolization (TAE) group, SR was similar to the TACE group, MR was 32% and 82%, survival was between 18 and 88 months with a survival rate of 40-67%, and BR was between 50% and 69%. Radiofrequency ablation (RFA), either percutaneous or during surgery, has been associated with SR of 71-95% for a mean duration of 8-10 months, BR of 65%, and mean SP of 1.6 years after ablation. The mean survival following surgical resection for operable cases is 4.26 years ± S.D.: 1.1.

Conclusion

The interventional protocols for the management of liver metastases from neuroendocrine tumors: for oligonodular liver metastatic deposits, local resection or RFA and/or LITT is recommended, while in multinodular diseases with higher tumor load, TACE or TAE is recommended.     

超声造影对肝脏转移癌的诊断应用价值

目的:探讨超声造影对肝脏转移癌的诊断应用价值.方法:对49例恶性肿瘤患者肝脏行常规超声检查及低机械指数超声造影检查,对肝内转移性病灶超声造影表现进行分析.结果:经超声造影新发现47个病灶,其中小于1.0cm的病灶占55.3%(26/47).肝转移病灶的增强模式可分为4种:A.病灶周边快速环状强化60/131(45.8%),病灶内部呈低或无增强,之后周边增强部分造影剂迅速退出呈低增强;B.病灶于动脉期呈快速整体强化并迅速廓清51/131(38.9%);C.病灶于动脉期和门脉期基本与肝脏实质同步强化,延迟晚期呈低增强12/131(9.2%);D.病灶于造影三期均低于肝实质呈低增强表现8/119(6.1%).结论:肝脏转移病灶来源和大小不同其增强模式表现亦不相同;实时超声造影可提高对肝脏转移病灶尤其可提高直径小于1.0cm的微小转移灶的检出率.     

Multiphase contrast-enhanced helical CT of liver metastases from renal cell carcinoma

The aim of this study was to evaluate whether in patients with metastatic renal cell carcinoma (RCC) multiphase liver studies would improve detection of metastatic liver disease. Forty-six consecutive patients with known metastatic RCC underwent standardized non-contrast and triphasic contrast enhanced hepatic CT examinations as part of their routine imaging studies. Once a liver abnormality was detected, it was characterized as metastatic by a panel of three radiologists who followed pre-set criteria. These criteria included change in size, biopsy results and lack of benign features. Presence and conspicuity of liver metastases were graded using a five-point scale by consensus of a panel of three radiologists. The highest number of lesions evaluated per patient was limited to ten. Seventy-two liver metastases were detected in 16 patients. Of these, 54 were seen on unenhanced scans; 47 in the hepatic arterial (HA) phase, at 25 s; 65 in the portal-venous (PV) phase, at 60 s; and 49 in delayed images, at 90 s. Scanning only during the PV phase would have missed seven lesions (10%), six of which were seen on unenhanced images and six were seen in HA phase. All patients with metastatic liver disease would have been identified by combination of unenhanced and PV phase or by HA and PV phase scanning. Forty-two lesions were graded more conspicuous on the PV phase, whereas 18 (25%) were more conspicuous on the HA phase. The combination of unenhanced, HA and PV scanning should be considered in the initial evaluation of patients with metastatic RCC for improved lesion detection and characterization. Subsequently, the combination of unenhanced and PV phase imaging is preferred.     

Diagnosis of colorectal hepatic metastases: comparison of contrast-enhanced CT, contrast-enhanced US, superparamagnetic iron oxide-enhanced MRI, and gadoxetic acid-enhanced MRI

Purpose:

To compare the diagnostic accuracy of contrast‐enhanced computed tomography (CE‐CT), contrast‐enhanced ultrasonography (CE‐US), superparamagnetic iron oxide‐enhanced magnetic resonance imaging (SPIO‐MRI), and gadoxetic acid‐enhanced MRI (Gd‐EOB‐MRI) in the evaluation of colorectal hepatic metastases.

Materials and Methods:

In all, 111 patients with colorectal cancers were enrolled in this study. Of the 112 metastases identified in 46 patients, 31 in 18 patients were confirmed histologically and the remaining 81 in 28 patients were confirmed by follow‐up imaging. CE‐CT, CE‐US, SPIO‐MRI, and Gd‐EOB‐MRI were evaluated. Mean (of three readers, except for CE‐US) area under the receiver operating characteristic curve (A_z), sensitivities, and positive predictive values (PPV) were calculated. Each value was compared to the others by variance z‐test or chi‐square test with Bonferroni correction.

Results:

For all lesions, mean A_z and sensitivity of Gd‐EOB‐MRI (0.992, 95% [56/59]) were significantly greater than those of CE‐CT (0.847, 63% [71/112]) and CE‐US (0.844, 73% [77/106]). For lesions ≤1 cm, mean A_z and sensitivity of Gd‐EOB‐MRI (0.999, 92% [22/24]) were significantly greater than those of CE‐CT (0.685, 26% [13/50]) and CE‐US (0.7, 41% [18/44]). Mean A_z (95% CI) of SPIO‐MRI for all lesions (0.966 [0.929–0.987]) and lesions ≤ 1 cm (0.961 [0.911–0.988]) were significantly greater than those of CE‐CT and CE‐US. Mean sensitivity of SPIO‐MRI for lesions ≤1 cm (63%, 26/41) was significantly greater than that of CE‐CT.

Conclusion:

Gd‐EOB‐MRI and SPIO‐MRI were more accurate than CE‐CT and CE‐US for evaluation of liver metastasis in patients with colorectal carcinoma. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Therapy monitoring using dynamic MRI: Analysis of lung motion and intrathoracic tumor mobility before and after radiotherapy

A frequent side effect after radiotherapy of lung tumors is a decrease of pulmonary function accompanied by dyspnea due to developing lung fibrosis. The aim of this study was to monitor lung motion as a correlate of pulmonary function and intrathoracic tumor mobility before and after radiotherapy (RT) using dynamic MRI (dMRI). Thirty-five patients with stage I non-small-cell lung carcinoma were examined using dMRI (trueFISP; three images/s). Tumors were divided into T1 and T2 tumors of the upper, middle and lower lung region (LR). Maximum craniocaudal (CC) lung dimensions and tumor mobility in three dimensions were monitored. Vital capacity (VC) was measured and correlated using spirometry. Before RT, the maximum CC motion of the tumor-bearing hemithorax was 5.2±0.9 cm if the tumor was located in the lower LR (middle LR: 5.5±0.8 cm; upper LR: 6.0±0.6 cm). After RT, lung motion was significantly reduced in the lower LR (P<0.05). Before RT, the maximum CC tumor mobility was significantly higher in tumors of the lower LR 2.5±0.6 vs. 2.0±0.3 cm (middle LR; P<0.05) vs. 0.7±0.2 cm (upper LR; P<0.01). After RT, tumor mobility was significantly reduced in the lower LR (P<0.01) and in T2 tumor patients (P<0.05). VC showed no significant changes. dMRI is capable of monitoring changes in lung motion that were not suspected from spirometry. This might make the treatment of side effects possible at a very early stage. Changes of lung motion and tumor mobility are highly dependent on the tumor localization and tumor diameter.     

MRI of bone metastases

Some knowledge of MR theory is required to be able to achieve high contrast between bone metastases and normal marrow. Three factors are used in MR to diagnose bone metastases: fat–water distribution, artifacts induced by bone trabeculae, and uptake of contrast medium. Using MR-histological correlations based on specimens of the lumbar spine, and studies of patients, we explain the advantages and limitations of sequences studying fat and water (spin-echo T1, STIR, in- and out-of-phase gradient echo, fat presaturation), bone trabeculae (gradient echo with long TE), and the injection of contrast medium. Received 27 October 1997; Revision received 16 February 1998; Accepted 18 February 1998     

Assessment of colorectal liver metastases using MRI and CT: Impact of observer experience on diagnostic performance and inter-observer reproducibility with histopathological correlation

Introduction

To compare the diagnostic performance and inter-observer reproducibility of CT and MRI in detecting colorectal liver metastases (CRLM) of observers with different levels of experience.

Materials and methods

Data from 51 CT and 54 MRI examinations of 105 patients with CRLM were analysed. Intraoperative and histopathological findings served as the reference standard. Analyses were performed by four observers with varying levels of experience regarding imaging of CRLM (reviewers A, B, C and D with respectively >20, >5, <1 and 0 years of experience). Per-segment sensitivity, specificity, Cohen's kappa (κ) for diagnosed segments and Intra-class Correlation Coefficients (ICC) for reported number of lesions were calculated.

Results

CT sensitivity and specificity was for reviewer A 89.71%/94.41%, B 78.50%/88.37%, C 63.55%/85.58%, D 84.11%/78.60% and regarding MRI A 90.40%/95.43%, B 74.40%/90.04%, C 60.00%/85.89% and D 65.60%/75.90%. The overall inter-observer agreement was higher for CT (κ = 0.43, p < 0.001; ICC = 0.75, p < 0.001) than MRI (κ = 0.38, p < 0.001; ICC = 0.65, p < 0.001). The experienced reviewers A and B achieved better agreement for MRI (κ = 0.54, p < 0.001; ICC = 0.77, p < 0.001) than CT (κ = 0.52, p < 0.00; ICC = 0.76, p < 0.001) unlike the less experienced C and D (MRI κ = 0.38, ICC = 0.63 and CT κ = 0.41, ICC = 0.74, respectively, p < 0.001).

Conclusions

The proficiency in detection of CRLM is significantly influenced by observer experience, although CT interpretation is less affected than MRI analysis.     

Diffusion-weighted and dynamic contrast-enhanced MRI in evaluation of early treatment effects during neoadjuvant chemotherapy in breast cancer patients

Purpose:

To use dynamic contrast‐enhanced (DCE) and diffusion‐weighted (DW) MRI at 3 Tesla (T) for early evaluation of treatment effects in breast cancer patients undergoing neoadjuvant chemotherapy (NAC), and assess the reliability of DW‐MRI.

Materials and Methods:

DW‐ and DCE‐MRI acquisitions of 15 breast cancer patients were performed before and after one cycle of NAC. MRI tumor diameter and volume, apparent diffusion coefficient (ADC) and kinetic parameters (K^trans, v_e) were derived. The reliability of ADC before NAC was assessed. Changes in MRI parameters after NAC were analyzed, and logistic regression analysis was used to find the best predictors for pathologic response.

Results:

The reliability for ADC values was high, with intraclass correlation coefficient of 0.84 (P = 0.001). After one cycle of NAC, MRI tumor diameter (8%, P = 0.005) and tumor volume (30%, P = 0.008) was reduced for all patients, while ADC mean values increased (0.12 mm²/s, P = 0.008). The best predictor for treatment response was a change in MRI tumor diameter with mean error rate of 0.167 (13% for responders, 5% for nonresponders, P = 0.291).

Conclusion:

Changes in MRI derived tumor diameter and ADC after only one cycle of NAC could provide a valuable tool for early evaluation of treatment effects in breast cancer patients. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.     

Diagnostic value of apparent diffusion coefficient calculated with diffusion-weighted MRI for quantification of liver fibrosis

Aim of the work

To evaluate the diagnostic values of the hepatic ADC calculated with diffusion-weighted MRI for quantification of the hepatic fibrosis in patients with chronic viral hepatitis.

Subjects and methods

Thirty-eight chronic viral hepatitis C patients with similar control group were examined by 1.5 Tesla MR scanner with diffusion gradient encoding in three orthogonal directions at b values of (300, 500, 700, and 1000 s/mm²). They were correlated to biopsy finding and graded according to Ishak scoring system. Hepatic ADC values were measured for both patients and control groups.

Results

The best correlation between ADC values and biopsy were seen at b values 300, 700, and 1000 s/mm², which showed high sensitivity, specificity, positive, and negative predictive values, with lesser correlation were obtained at b values of 500 s/mm². Cut off values between different grades of fibrosis were calculated and presented in the text.

Conclusion

ADC measured with DWI is a reliable non-invasive technique for quantification of liver fibrosis, and could replace liver biopsy in certain cases.     

Hepatobiliary contrast agents for contrast-enhanced MRI of the liver: properties,clinical development and applications

Hepatobiliary contrast agents with uptake into hepatocytes followed by variable biliary excretion represent a unique class of cell-specific MR contrast agents. Two hepatobiliary contrast agents, mangafodipir trisodium and gadobenate dimeglumine, are already clinically approved. A third hepatobiliary contrast agent, Gd-EOB-DTPA, is under consideration. The purpose of this review is to provide an overview on the properties, clinical development and application of these three hepatobiliary contrast agents. Bolus injectable paramagnetic hepatobiliary contrast agents combine established features of extracellular agents with the advantages of hepatocyte specificity. The detection and characterisation of focal liver disease appears to be improved compared to unenhanced MRI, MRI with unspecific contrast agents and contrast-enhanced CT. To decrease the total time spent by a patient in the MR scanner, it is advisable to administer the agent immediately after acquisition of unenhanced T1-w MRI. After infusion or bolus injection (with dynamic FS-T1-w 2D or 3D GRE) of the contrast agent, moderately and heavily T2w images are acquired. Post-contrast T1-w MRI is started upon completion of T2-w MRI for mangafodipir trisodium and Gd-EOB-DTPA as early as 20 min following injection, while gadobenate dimeglumine scans are obtained >60 min following injection. Post-contrast acquisition techniques with near isotropic 3D pulse sequences with fat saturation parallel the technical progress made by MSCT combined with an unparalleled improvement in tumour-liver contrast. The individual decision that hepatobiliary contrast agent one uses is partly based on personal preferences. No comparative studies have been conducted comparing the advantages or disadvantages of all three agents directly against each other.     

Delineation of liver necrosis using double contrast-enhanced MRI

The purpose of this study was to demonstrate the potential usefulness of the combination of gadolinium and dysprosium to enhance the difference between normal and necrotic liver tissue. Small regions of acute necrosis were induced by injecting 200–300 μl of 95% alcohol into the liver of 26 rats. MRI was performed 24 hours after necrosis induction, before and immediately after injection of one or both contrast agents. Using a mixed T1/T2-weighted sequence, the signal intensity (SI) of the normal liver was reduced by 70%, whereas the necrotic regions had more than a 50% increase in SI after double contrast. The region that was enhanced corresponded largely with the region of necrosis as observed postmortem. The lesion size, when identified, was largely underestimated using either of the agents alone, albeit using the common pulse sequences. The double contrast effect of simultaneous administration of gadolinium and dysprosium allows accurate delineation of liver necrosis.