Gd-EOB-DTPA-enhanced magnetic resonance imaging for bile duct intraductal papillary mucinous neoplasms

AIM: To investigate gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) of intraductal papillary mucinous neoplasms of the bile duct (IPMN-B).METHODS: The imaging findings of five cases of IPMN-B which were pathologically confirmed at our hospital between March 2012 and May 2013 were retrospectively analyzed. Three of these cases were diagnosed by duodenal endoscopy and biopsy pathology, and two cases were diagnosed by surgical pathology. All five patients underwent enhanced and non-enhanced computed tomography (CT), magnetic resonance cholangiopancreatography, and Gd-EOB-DTPA-enhanced MRI; one case underwent both Gd-EOB-DTPA-enhanced MRI and positron emission tomography-CT. The clinical data and imaging results for these cases were compared and are presented.RESULTS: Conventional imaging showed diffuse dilatation of bile ducts and multiple intraductal polypoid and papillary neoplasms or serrated changes along the bile ducts. In two cases, Gd-EOB-DTPA-enhanced MRI revealed dilated biliary ducts and intraductal tumors, as well as filling defects caused by mucin in the dilated bile ducts in the hepatobiliary phase. Gd-EOB-DTPA-enhanced MRI in one case clearly showed a low-signal tumor in the hepatobiliary phase, similar to what was seen by positron emission tomography-CT. In two patients, routine inspection was unable to discern whether the lesions were inflammation or tumors. However, Gd-EOB-DTPA-enhanced MRI revealed a pattern of gradual enhancement during the hepatobiliary phase, and the signal intensity of the lesions was lower than the surrounding liver parenchyma, suggesting tissue inflammation in both cases, which were confirmed by surgical pathology.CONCLUSION: Gd-EOB-DTPA-enhanced MRI reveals the intraductal mucin component of IPMN-B in some cases and the extent of tumor infiltration beyond the bile ducts in invasive cases.     

A case of multiple intra-abdominal splenosis with computed tomography and magnetic resonance imaging correlative findings

Hepatic splenosis refers to heterotopic auto- transplantation and implantation of splenic tissue resulting from the spillage of cells from the spleen after splenic trauma or splenectomy. The true incidence of splenosis is unknown, because this entity is usually an incidental finding at surgery. Splenic implants are usually multiple, and can be localized anywhere in the peritoneal cavity. Splenic implants in the peritoneal cavity may be confused with renal tumors, abdominal lymphomas and endometriosis. We describe computed tomography （CT） and magnetic resonance imaging （MRI） findings in a rare case of multiple intra-abdominal splenosis located along the hepatic surface and adjacent to the upper pole of the right kidney, mimicking a renal neoplasm.     

肝血管肉瘤的MRI表现

目的探讨原发性肝血管肉瘤（HAS）的MRI表现。方法回顾性分析第二军医大学东方肝胆医院2009至2011年经手术病理证实的3例HAS患者的临床、病理和术前MRI表现。结果3例HAS患者包括男性1例和女性2例,年龄35—71岁。所有病灶在MRI的TIWI和T2WI均表现为混合信号强度。所有病灶均存在肿瘤内出血、坏死。GD-DTPA增强扫描后动脉期病灶均为不均匀轻度强化,延迟期病灶表现为持续渐进增强而瘤中心无强化。结论当肝内肿瘤MRI表现为坏死、出血,增强后延迟期病灶渐进强化应考虑到HAS的可能。     

Volvulus of the gall bladder diagnosed by ultrasonography, computed tomography, coronal magnetic resonance imaging and magnetic resonance cholangio-pancreatography

A 54-year-old woman was admitted to our hospital with the complaint of right upper quadrant pain. Upon physical examination the vital signs of the patient were within normal ranges. Ultrasonography and computed tomography (CT) examination of the abdomen was obtained, which demonstrated a large dilatated cystic structure, measuring approximately 68.6 mm x 48.6 mm, with marked distension and inflammation. Additionally, the enhanced CT was characterized by the non-enhanced wall of the gallbladder. As the third examination in this study, magnetic resonance imaging (MRI), namely coronal MRI and magnetic resonance cholangio-pancreatography (MRCP), were performed. The MRCP demonstrated a dilatation of the gallbladder but detected no neck of the gallbladder. Simple cholecystectomy was performed. Macroscopic findings included a distended and gangrenous gallbladder, and closer examination revealed a counterclockwise torsion of 360 degrees on the gallbladder mesentery. Coronal MRI and MRCP showing characteristic radiography may be useful in making a definitive diagnosis.     

Reactive lymphoid hyperplasia of the liver: Perinodular enhancement on contrast-enhanced computed tomography and magnetic resonance imaging

We report the case of a 69-year-old woman with reactive lymphoid hyperplasia (RLH) of the liver. She underwent partial hepatectomy under a preoperative diagnosis of hepatocellular carcinoma; however, histopathological analysis revealed RLH. The liver nodule showed the imaging feature of perinodular enhancement in the arterial dominant phase on contrast-enhanced computed tomography and magnetic resonance imaging, which could be a useful clue for identifying RLH in the liver. Histologically, the perinodular enhancement was compatible with prominent sinusoidal dilatation surrounding the liver nodule.     

Advances in computed tomography and magnetic resonance imaging of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver cancer. Imaging is important for establishing a diagnosis of HCC and early diagnosis is imperative as several potentially curative treatments are available when HCC is small. Hepatocarcinogenesis occurs in a stepwise manner on a background of chronic liver disease or cirrhosis wherein multiple genes are altered resulting in a range of cirrhosis-associated nodules. This progression is related to increased cellularity, neovascularity and size of the nodule. An understanding of the stepwise progression may aid in early diagnosis. Dynamic and multiphase contrast-enhanced computed tomography and magnetic resonance imaging still form the cornerstone in the diagnosis of HCC. An overview of the current diagnostic standards of HCC in accordance to the more common practicing guidelines and their differences will be reviewed. Ancillary features contribute to diagnostic confidence and has been incorporated into the more recent Liver Imaging Reporting and Data System. The use of hepatocyte-specific contrast agents is increasing and gradually changing the standard of diagnosis of HCC; the most significant benefit being the lack of uptake in the hepatocyte phase in the earlier stages of HCC progression. An outline of supplementary techniques in the imaging of HCC will also be reviewed.     

Magnetic resonance imaging vs. ultrafast computed tomography for cardiac diagnosis

Ultrafast computed tomography (CT) and magnetic resonance imaging (MRI) generate high resolution tomographic cardiac images. Ultrafast CT requires intravenous injection of x-ray contrast combined with an image acquisition time of 50 msec. MRI requires no contrast injection, but has relatively long acquisition times due to gating. Both technologies can be used to evaluate cardiac chamber and great vessel dimensions, intracardiac and extracardiac masses, ventricular hypertrophy, left ventricular mass, congenital heart disease, regional and global left ventricular function, right ventricular function and pericardium. MRI is highly useful for detection and semi-quantitation of valvular regurgitation while ultrafast CT is not. Aortic and mitral valve stenosis can be detected by both, but MRI is the preferred study. Though both techniques can be used to assess coronary artery bypass graft status, ultrafast CT is the preferred method. It is concluded that ultrafast CT and MRI have broad applications for cardiac diagnosis.     

Imaging of liver disease: comparison between quadruple-phase multidetector computed tomography and magnetic resonance imaging

Background and Aim: To compare quadruple‐phase multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) for the assessment of focal and diffuse liver disease. Methods: Quadruple‐phase contrast‐enhanced MDCT and MRI of 37 consecutive patients were retrospectively reviewed by two readers (R1 and R2). In patients with focal liver lesions, the gold standard was histopathology (n = 17) and/or long‐term (>6 months) follow‐up imaging (n = 27) or transarterial chemoembolization (n = 1). Diffuse liver disease was confirmed by histopathology in all patients, when present. Results: Both readers identified 60 focal liver lesions on MDCT and 56 focal liver lesions on MRI. Gold standard diagnoses revealed 48 focal liver lesions in 25 patients. Diagnosis of malignant liver lesions revealed a sensitivity of 88% (R1) and 91% (R2) for MRI; 63% (R1) and 66% (R2) for MDCT; and a specificity of 75% (R1) and 79% (R2) for MRI; 50% (R1) and 64% (R2) for MDCT. MRI was superior to MDCT for the diagnosis of malignant focal liver lesions, when the mean areas under the alternative free‐response receiver operating characteristic curves (A_Z) were compared (MRI = 0.93 vs CT = 0.69), (P < 0.00001). Thirty‐three patients had histopathologically confirmed diffuse liver disease. Overall diagnosis of diffuse liver disease revealed a sensitivity of 88% (R1) and 92% (R2) for MRI; 75% (R1) and 74% (R2) for MDCT; and a specificity of 100% for both modalities by both readers. Conclusions: MRI is superior for the assessment of malignant focal liver lesions and diffuse liver disease compared to quadruple‐phase MDCT, and can be considered as primary diagnostic imaging modality for liver imaging.     

Diagnostic value of diffusion-weighted magnetic resonance imaging compared with fluorodeoxyglucose positron emission tomography/computed tomography for pancreatic malignancy: a meta-analysis using a hierarchical regression model

Background and Aim: To obtain diagnostic performance of diffusion‐weighted magnetic resonance imaging (DWI) and fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the detection of pancreatic malignancy. Methods: We performed a meta‐analysis of all available studies of the diagnostic performance of DWI and PET/CT for pancreatic malignancy. MEDLINE, EMBASE, Cochrane library and some other databases were searched for initial studies. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR?), and constructed summary receiver operating characteristic curves (SROC) using hierarchical regression models. Results: Across 16 studies with 804 patients, PET/CT sensitivity was 0.87 (95% confidence interval [CI], 0.82, 0.81) and specificity was 0.83 (95% CI, 0.71, 0.91). Overall, LR+ was 5.84 (95% CI, 4.59, 7.42) and LR? was 0.24 (95% CI, 0.17, 0.33). DWI sensitivity was 0.85 (95% CI, 0.74, 0.92) and specificity was 0.91 (95% CI, 0.71, 0.98). LR+ was 9.53 (95% CI, 2.41, 37.65) and LR? was 0.17 (95% CI, 0.09, 0.32). In subgroup analysis, the sensitivity of enhanced versus unenhanced PET/CT in the detection of pancreatic cancer was 0.91 (95% CI, 0.86, 0.96) versus 0.84 (95% CI, 0.78, 0.90) (P > 0.05), the specificity 0.88 (95% CI, 0.73, 1.00) versus 0.81 (95% CI, 0.69, 0.94) (P > 0.05). Conclusion: Positron emission tomography/computed tomography (PET/CT) was highly sensitive and DWI was a highly specific modality in diagnosing patients with pancreatic malignancy. PET/CT and DWI could play different roles in diagnosing pancreatic carcinoma. Enhanced PET/CT seems to be superior to unenhanced PET/CT. Further larger prospective studies are needed to establish its value for diagnosis in pancreatic cancer.     

Quantitative assessment of hepatic fibrosis in chronic hepatitis B and C: T1 mapping on Gd-EOB-DTPA-enhanced liver magnetic resonance imaging

AIM To assess the accuracy of Look-Locker on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid(GdEOB-DTPA)-enhanced magnetic resonance imaging(MRI) for staging liver fibrosis in chronic hepatitis B/C(CHB/C).METHODS We prospectively included 109 patients with CHB or CHC who underwent a 3.0-Tesla MRI examination, including T1-weighted and Look-Locker sequences for T1 mapping. Hepatocyte fractions(He F) and relaxation time reduction rate(RE) were measured for staging liver fibrosis. A receiver operating characteristic analysis using the area under the receiver operating characteristic curve(AUC) was used to compare thediagnostic performance in predicting liver fibrosis between He F and RE.RESULTS A total of 73 patients had both pathological results and MRI information. The number of patients in each fibrosis stage was evaluated semiquantitatively according to the METAVIR scoring system: F0, n = 23(31.5%); F1, n = 19(26.0%); F2, n = 13(17.8%); F3, n = 6(8.2%), and F4, n = 12(16.4%). He F by EOB enhancement imaging was significantly correlated with fibrosis stage(r =-0.808, P 0.05). AUC values for diagnosis of any(≥ F1), significant(≥ F2) or advanced(≥ F3) fibrosis, and cirrhosis(F4) using He F were 0.837(0.733-0.913), 0.890(0.795-0.951), 0.957(0.881-0.990), and 0.957(0.882-0.991), respectively. He F measurement was more accurate than use of RE in establishing liver fibrosis staging, suggesting that calculation of He F is a superior noninvasive liver fibrosis staging method.CONCLUSION A T1 mapping-based He F method is an efficient diagnostic tool for the staging of liver fibrosis.     

Direct comparison of computed tomography and magnetic resonance imaging for characterization of posterior left atrial morphology

Objective Accumulating evidence points to the central importance of the posterior left atrium (PLA) for atrial fibrillation (AF). Catheter ablation intended to cure AF is increasingly practiced; performance and assessment of this procedure is enhanced by accurate imaging of PLA anatomy. Prior reports have suggested that both computed tomographic (CT) and magnetic resonance (MR) imaging techniques provide accurate PLA images. These techniques have never been compared directly.Materials and methods Twenty patients referred for catheter ablation underwent preoperative imaging using both CT and MR. Each technique was used to create a multidimensional image of the PLA.Results Within patients, morphologic and dimensional PLA indices, including number of individual pulmonary venoatrial junctions, presence of ostial branches, circumference of each venoatrial junction, venoatrial junction “non-circularity”, and distance between ipsilateral superior and inferior venoatrial junctions, were well correlated.Conclusions CT and MR-based images of the PLA appear comparable. Technique selection should involve considerations of toxicity, tolerance, and local resources.Supported in part by an unrestricted grant from General Electric Healthcare.     

Imaging features of ciliated hepatic foregut cyst

Ciliated hepatic foregut cyst (CHFC) is a very rare cystic lesion of the liver that is histologically similar to bronchogenic cyst. We report one case of CHFC that was hard to distinguish from solid-cystic neoplasm in imaging features. Magnetic resonance imaging was helpful in differentiating these cysts from other lesions.     

Liver metastases:Contrast-enhanced ultrasound compared with computed tomography and magnetic resonance

The development of ultrasound contrast agents with excellent tolerance and safety profiles has notably improved liver evaluation with ultrasound(US)for several applications,especially for the detection of metastases.In particular,contrast enhanced ultrasonography(CEUS)allows the display of the parenchymal microvasculature,enabling the study and visualization of the enhancement patterns of liver lesions in real time and in a continuous manner in all vascular phases,which is similar to contrast-enhanced computed tomography(CT)and contrast-enhanced magnetic resonance imaging.Clinical studies have reported that the use of a contrast agent enables the visualization of more metastases with significantly improved sensitivity and specificity compared to baseline-US.Furthermore,studies have shown that CEUS yields sensitivities comparable to CT.In this review,we describe the state of the art of CEUS for detecting colorectal liver metastases,the imaging features,the literature reports of metastases in CEUS as well as its technique,its clinical role and its potential applications.Additionally,the updated international consensus panel guidelines are reported in this review with the inherent limitations of this technique and best practice experiences.     

Liver magnetic resonance imaging: State of the art

Magnetic resonance imaging (MRI) has now been used for about three decades to characterize the human liver in a non-invasive way, that is without the need of using ionizing radiation or removing tissue samples. During the past few years, technical progress has been considerable and novel applications of MRI have been implemented in the clinic. The beginning of a new decade offers an excellent opportunity for having fi ve experts to present their view on the current status of MRI (and magnetic resonance spec...     

Three-Tesla magnetic resonance elastography for hepatic fibrosis: Comparison with diffusion-weighted imaging and gadoxetic acid-enhanced magnetic resonance imaging

AIM: To evaluate the feasibility of 3-Tesla magnetic resonance elastography (MRE) for hepatic fibrosis and to compare that with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced magnetic resonance (MR) imaging.METHODS: Forty-two patients were included in the study. On MRE, mean stiffness values were measured on the elastograms in kilopascals. The apparent diffusion coefficient (ADC) of the liver was measured using DWI. On gadoxetic acid enhanced MR, the contrast enhancement index (CEI) was calculated as signal intensity (SI)_post/SI_pre, where SI_post is liver-to-muscle SI ratio on hepatobiliary phase images and SI_pre is that on nonenhanced images. Correlation between aspartate aminotransferase to the platelet ratio index (APRI) and three MR parameters was assessed. Each MR parameter was compared between a hepatic fibrosis (HF) group and non-hepatic fibrosis (nHF) group.RESULTS: Liver stiffness showed strong positive correlation with APRI [Spearman correlation coeffiecient (r) = 0.773, P < 0.0001], while ADC and CEI showed weak or prominent negative correlation (r = -0.28 and -0.321, respectively). In the HF group, only liver stiffness showed strong correlation with APRI (r = 0.731, P < 0.0001). Liver stiffness, ADC, and APRI were significantly different between the HF group and nHF group.CONCLUSION: MRE at 3-Tesla could be a feasible method for the assessment of hepatic fibrosis.     

Assessment of cancer cell differentiation in small hepatocellular carcinoma by computed tomography and magnetic resonance imaging

AIM: To study whether cancer cell differentiation in small hepatocellular carcinoma (HCC) can be assessed by computed tomography (CT) and magnetic resonance (MR) imaging. METHODS: We retrospectively evaluated the relationship between cancer cell differentiation in 127 HCC 3 cm or less in diameter (113 patients) and CT and MR images. Images were reviewed in a consensus conference by three authors (SA, TY, and ME). Histopathological diagnosis of HCC was made from liver specimens obtained by sonographically guided biopsy. RESULTS: The degree of histological differentiation of cancer cells was significantly different between HCC that were isodense with liver parenchyma in both artery-dominant and equilibrium phases in contrast-enhanced CT and tumors that were hyperdense in the artery-dominant phase and iso- or hypodense in the equilibrium phase (P = 0.0054), as well as tumors that were iso- or hypodense artery-dominant and hypodense equilibrium (P = 0.0002). Histological differentiation of lesions that were hyperintense in T1-weighted images and hypointense in T2-weighted images differed significantly from those with the opposite MR characteristics (P = 0.0122). In T1-weighted fat-suppression images and T2-weighted images, respectively, the degree of histological differentiation was significant between the hypointense/hyperintense and the hyperintense/hypointense patterns (P < 0.0001), as well as the hyperintense/isointense (P = 0.0296), the hyperintense/hyperintense (P = 0.0434), and the isointense/hyperintense (P = 0.0171). Using these differences an equation was developed that could determine with 76% accuracy whether the tumors were well or less-well differentiated. CONCLUSION: CT and MR imaging patterns were useful in predicting the degree of histological differentiation of cancer cells in HCC.     

Contrast-enhanced multiple-phase imaging features in hepatic epithelioid hemangioendothelioma

AIM:To investigate and review the contrast-enhanced multiple-phase computed tomography(CEMP CT)and magnetic resonance imaging(MRI)findings in patients with pathologically confirmed hepatic epithelioid hemangioendothelioma(HEHE).METHODS:Findings from imaging examinations in 8 patients(5 women and 3 men)with pathologically confirmed HEHE were retrospectively reviewed(CT images obtained from 7 patients and MR images obtained from 6 patients).The age of presentation varied from 27 years to 60 years(average age ...