MRI of perforated gall bladder

Gall bladder perforation is a dreaded complication of acute cholecystitis that, if not diagnosed early in the course, might have a poor prognosis. Both CT and ultrasonography have been used until now extensively for the diagnosis of acute cholecystitis, but diagnosis of perforation is always difficult. Magnetic resonance, by its superior soft tissue resolution and multiplanar capability, is a better modality and should fare better than ultrasonography and CT, as demonstrated in our case. Magnetic resonance imaging demonstrates the wall of the gall bladder and defects to a much better advantage and more convincingly. In addition, MR colangiopancreatography images demonstrate the biliary tree better than other modalities. We suggest that in the case of acute cholecystitis, if perforation is suspected and CT and ultrasonography are not conclusive, MR should be the modality of choice. It can be used as a first line of investigation; however, it might not be cost‐effective.     

磁共振弥散加权成像(DWI)在食管癌放疗中的应用进展

DWI作为MR功能成像的重要组成部分,可以提供定性和定量的信息以帮助肿瘤评估,更好的区分食管病灶及纵隔淋巴结转移。DWI-CT融合图像更有利于靶区勾画。在食管癌的放疗或同步放化疗中,监测ADC值变化有助于早期疗效预测和预后判断,DWI检查能弥补单纯依据造影评价食管癌近期疗效的不足。本文综述了DWI在食管癌诊断、靶区勾画、疗效评估及判断预后等在放疗中的应用进展。     

Detection of malignant bone marrow involvement with dynamic contrast-enhanced magnetic resonance imaging.

BACKGROUND: The purpose of this study was to evaluate the role of dynamic contrast-enhanced magnetic resonance imaging (dMRI) in detecting bone marrow involvement in cancer patients. PATIENTS AND METHODS: We studied 50 consecutive patients with histologically confirmed malignant dissemination to the bone marrow, using dMRI of the lumbosacral spine. Time-signal intensity curves were generated from regions of interest (ROIs) obtained from areas of obvious bone marrow disease (group B). In 16 patients from group B with focal disease, ROIs were also placed on areas with apparently normal bone marrow on static magnetic resonance images (group C). Twenty-two patients with no history of malignancy were used as a control group (group A). Wash-in (WIN) and wash-out (WOUT) rates, time to peak (TTPK), time to maximum slope (TMSP) values and WIN/TMSP ratios were calculated for each patient. Mean values for the three groups were compared statistically. Six patients from group B had follow-up dMRI after chemotherapy: four patients achieved a clinical partial response and two had resistant disease. RESULTS: A significant difference was found between groups A and B for all values. Between groups A and C, in spite of the similar static MRI appearance, all values were significantly different. Between groups B and C, a significant difference was found for WIN, WOUT rates and WIN/TMSP ratio. Follow-up dMRI data analysis correlated well with clinical staging. CONCLUSIONS: dMRI can distinguish normal from malignant bone marrow. It may identify malignant bone marrow infiltration in patients with negative static MRI and serve as both a diagnostic and prognostic tool for patients with bone marrow malignancies.     

The evaluation of human breast lesions with magnetic resonance imaging and proton magnetic resonance spectroscopy

Purpose. MR spectroscopy (MRS) assists in lesion characterization and diagnosis when combined with magnetic resonance imaging (MRI). Cancerous lesions demonstrate elevated composite choline levels arising from increased cellular proliferation. Our study investigated if MR spectroscopy of the breast would be useful for characterizing benign and malignant lesions. Materials and methods. Single voxel proton MR spectroscopy (MRS) was acquired as part of an MR imaging protocol in 38 patients referred upon surgical consultation. The MR spectra were read independently in a blinded fashion without the MR images by three spectroscopists. The MRI exam was interpreted in two settings: (a) as a clinical exam with detailed histories and results from previous imaging studies such as mammography or ultrasound included and (b) as a blinded study without prior histories or imaging results. Results. Elevated choline levels were demonstrated by MRS in 19 of the 23 confirmed cancer patients. The sensitivity and specificity for determining malignancy from benign breast disease with MRS alone were 83 and 87%, respectively, while a blinded MRI review reported 95 and 86%, respectively. Conclusions. Proton MR spectroscopy provides a noninvasive, biochemical measure of metabolism. The technique can be performed in less than 10min as part of an MRI examination. MRI in combination with MRS may improve the specificity of breast MR and thereby, influence patient treatment options. This may be particularly true with less experienced breast MRI readers. In exams where MRI and MRS agree, the additional confidence measure provided by MRS may influence the course of treatment.     

Magnetic resonance cholangiopancreatography

Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive imaging method for examining the biliary and pancreatic ducts. The technique uses heavily T2-weighted imaging, which produces high signal from bile and other static fluids by virtue of their long T2 time, while suppressing background signal. Fast scanning techniques, particularly half-Fourier fast spin-echo techniques, are continuing to improve image resolution and allow scans within short breath-holds, reducing the effects of respiratory movement. The MRCP method has reached a level of resolution and reliability where it may well largely replace diagnostic endoscopic retrograde cholangiopancreatography (ERCP) in the near future. A review of MRCP techniques and imaging findings is presented with emphasis on half-Fourier imaging, with reference to potential clinical indications and limitations. Use of MRCP shows a high sensitivity and specificity for detection of biliary dilatation, calculi, strictures and anatomical variants. Experience with MR imaging of the pancreatic duct is less extensively described in the literature, but pancreatic duct dilatation, calculi and anatomy can now be reliably detected. However, as experience with MRCP increases, some sources of errors and limitations are becoming apparent, with image artefacts, and gas, blood or sludge within ducts potentially mimicking stones or strictures.     

Accuracy of nasopharyngeal carcinoma staging by magnetic resonance imaging

To audit the accuracy of magnetic resonance (MR) staging of nasopharyngeal carcinoma (NPC) in daily reporting, the MR images of 101 adult patients with newly diagnosed NPC reported between December 1996 and February 2002 were reviewed retrospectively. Based on the American Joint Committee on Cancer/International Union Against Cancer (AJCC/UICC) TNM staging criteria (1997), the tumour staging obtained from the MR reports and the MR films was compared by two experienced head and neck radiologists. The number of patients being upstaged, downstaged or unchanged was noted. In all stages, the NPC staging obtained from the MR reports revealed 18 (17.8%) understaged, eight (7.9%) overstaged and 75 (74.2%) the same stage when compared to the staging obtained from the MR films based on the AJCC/UICC criteria. The percentage of patients being understaged or overstaged, in decreasing order of frequency, were stages II, III, IV and I. Magnetic resonance of NPC should be reported by radiologists who are not only familiar with the pathology of this condition and its pattern of spread but who should also base their reports on the AICC/UICC staging criteria. The necessity to improve our MR staging accuracy is largely because it determines the type of therapy to be given and this has to be appropriate and adequate for a successful treatment.     

磁共振成像在子宫内膜癌的诊断及分期中的作用研究

目的:探讨MRI在子宫内膜癌的诊断、分期中的作用.方法:回顾性研究273例经术后病理检查明确诊断的子宫内膜癌患者,根据其术前MRI表现,以FIG02009新分期方法结合病理分期结果进行评估.结果:273例患者中Ⅰa期136例,Ⅰb期46例,Ⅱ期51例,Ⅲa期8例,Ⅲb期7例,Ⅲcl期8例,Ⅲ2期4例,Ⅳa期6例,Ⅳb期7例,MRI对子宫内膜癌分期正确率为93.4％,与病理分期比较无显著统计学差异(P＞0.05).结论:MRI对子宫内膜癌的诊断及分期具有较高准确性,在临床治疗方式及预后评估中具有重要意义.     

Fast magnetic resonance imaging in spinal trauma

In a prospective comparison between fast magnetic resonance imaging (MRI) sequences and conventional spin-echo in a series of 20 patients, gradient-echo imaging was found to be inferior to spin-echo, especially in the visualization of spinal cord oedema, and the use of a rapid spin-echo sequence was limited by inferior visualization of haemorrhage. While the use of a combination of these two fast imaging techniques resulted in equivalent results to conventional spin-echo, the increased imaging time suggests that fast MRI cannot, as yet, replace conventional spin-echo techniques in acute spinal trauma.     

Imaging of adenomyomatosis of the gall bladder

Adenomyomatosis is a relatively common abnormality of the gall bladder, with a reported incidence of between 2.8 and 5%. Although mainly confined to the adult study group, a number of cases have been reported in the paediatric study group. It is characterized pathologically by excessive proliferation of the surface epithelium and hypertrophy of the muscularis propria of the gall bladder wall, with invagination of the mucosa into the thickened muscularis forming the so-called 'Rokitansky-Aschoff' sinuses. The condition is usually asymptomatic and is often diagnosed as an incidental finding on abdominal imaging. The radiological diagnosis is largely dependent on the visualization of the characteristic Rokitansky-Aschoff sinuses. As the condition is usually asymptomatic, the importance of making a correct diagnosis is to prevent misinterpretation of other gall bladder conditions such as gall bladder cancer, leading to incorrect treatment. In the past, oral cholecystography was the main imaging method used to make this diagnosis. In most institutions, oral cholecystography is no longer carried out, and the diagnosis is now more commonly seen on cross-sectional imaging. In this review article, we describe the manifestations of adenomyomatosis on the various imaging methods, with an emphasis on more modern techniques such as magnetic resonance cholangiopancreatography. A brief section on oral cholecystography to aid readers familiar with this technique in understanding the comparable imaging features on more modern imaging techniques is included.     

磁共振弥散加权成像对鼻咽癌靶区勾画和复发转移预测的临床价值研究

目的 探讨磁共振弥散加权成像(DWMRI)能否预测鼻咽癌调强放疗后复发和转移以及判断靶区范围的价值。方法 回顾 2008年6月起初次调强放疗的鼻咽癌病历资料,选择有复发或转移 36例和无复发转移 36例作对照。对两组病例在DWMRI上测量其疗前肿瘤表观弥散系数(ADC值),并行成组t检验推测ADC值是否能预测鼻咽癌复发和转移。回顾分析局部区域复发病例放疗前MRI,从影像学角度分析DWMRI是否有助于判断靶区范围。结果 复发或转移组、对照组疗前ADC均值分别为(0.753±0.091)×10^－3、(0.793±0.094)×10^－3 mm²/s (t=－1.79,P=0.078)。影像学回顾分析显示DWMRI在低本底上突显了肿瘤侵犯范围,局部区域复发共 16例,15例疗前常规MRI弥散序列在病变范围上一致,1例复发患者DWMRI序列较常规序列更准确地预测了病变复发部位。结论 DWMRI结合常规MRI可更准确地判断鼻咽癌靶区范围,但其疗前ADC值的高低与鼻咽癌复发或转移并无关联。     

Assessment of abdominal aortic aneurysm with magnetic resonance imaging

Pre-operative imaging of abdominal aortic aneurysms (AAA) is important in determining suitability for operation and operative approach. Ultrasound imaging is an excellent screening modality but is relatively poor at identifying renal arteries and the extent of iliac involvement. Computed tomography scanning with intravenous contrast and arteriography are invasive modalities that are associated with a small risk. Magnetic resonance imaging (MRI) offers the potential of accurate anatomical definition without use of contrast agents and passage of an intra-arterial catheter. Eight patients who had their AAA evaluated with MRI are reported. All had renal arteries accurately defined, intraaneurysmal thrombosis was well delineated, and iliac extension was correctly identified in four cases. The initial experience has been most encouraging and the authors consider that MRI may become the investigation of choice for pre-operative AAA assessment.     

肺癌DW-MRI临床应用研究进展

目的：总结国内外关于磁共振弥散加权成像在肺癌中的研究进展。方法：应用PubMed和CNKI期刊全文数据库检索系统,以“肺肿瘤、磁共振成像、DwI”为关键词,检索2007-01-2013-05的相关文献,共检索到英文文献103篇,中文文献304篇。纳入标准：1）磁共振弥散加权成像对肺癌的诊断价值;2）磁共振弥散加权成像对转移淋巴结的诊断价值;3）磁共振弥散加权成像对肺癌疗效监测的价值。根据纳入标准,符合分析文献29篇。结果：磁共振弥散加权成像能够区分肺部肿瘤的良恶性,其敏感性、特异性与18F-FDGPET相当,并能够依据表观弥散系数（apparentdiffusioncoeffi-cient,ADC）值及信号强度对肿瘤的病理类型进行初步鉴别。转移性淋巴结的ADC值较低,DwI在发现微小淋巴结转移方面,准确性和敏感性均比PET-CT高。ADC值可以早期评价肺癌放化疗及射频消融疗效,特异性和敏感性均优于PET-CT。结论：DW-MRI能明确诊断肺部肿瘤,并能早期评价肺癌疗效,可以成为新的肺癌诊疗手段。     

Ovarian vascular pedicle sign in ovarian metastasis arising from gall bladder carcinoma

A case of a large mass in the pelvis confirmed to be a rare ovarian metastasis arising from a primary adenocarcinoma of the gall bladder is presented. The value of the recently described ovarian pedicle sign in confirming the organ of origin of the pelvic mass is emphasized.     

Bilateral optic pathway glioma with intracranial calcification: Magnetic resonance imaging and magnetic resonance spectroscopy findings

Optic nerve glioma is the most common primary neoplasm of the optic nerve in childhood. It can extend intracranially along the optic pathway (optic pathway glioma). The lesion tends to present with decreased visual acuity in the affected eye, but can cause additional symptoms when it is large. Local involvement within the orbit can be characterized using CT, but MRI is superior in showing the intracranial extent of the lesion. Intracranial calcification in optic pathway glioma is rare. We present a rare case of optic pathway glioma with calcification in the intracranial component. Also, we describe MR spectroscopy (MRS) findings in this case.     

MRI在鼻咽癌临床分期中的价值

背景与目的:鼻咽癌的临床分期主要依据影像学资料.本研究探讨磁共振成像(magnetic resonance imaging,MRI)技术在鼻咽癌'92临床分期中的价值.方法:2002年5月至2005年6月,共有100例经病理组织学诊断并在治疗前能同时或短时间内(不超过15天)作计算机断层扫描(computed tomography,CT)增强扫描和MRI增强扫描的鼻咽癌初治患者.其中男性74例,女性26例,年龄21～60岁,中位年龄46岁.分别计算两种检查方法所显示的各解剖部位受侵犯的阳性率,用卡方检验比较这两种检查方法对各解剖部位的检出率.按鼻咽癌'92分期标准,分别以CT加临床体检和MRI加临床体检对100例患者进行临床分期,用卡方检验比较两种方法所划分的各期病例数的构成比.结果:CT和MRI对颅底骨质破坏的检出率分别为31.0%(31/100)和56.0%(56/100),两种检查方法比较差异有显著性(χ2=12.715,P=0.000).CT和MRI对咽后淋巴结的检出率分别为40.0%和55.0%,差异有显著性(X2=4.511,P=0.034).对于T分期,用CT和MRI划分的各期病例数构成比差异有显著性(χ2=8.339,P=0.039),而CT和MRI对于N分期(χ2=0.275,P=0.965)和临床分期(χ2=5.525,P=0.137)划分的各期病例数构成比比较则无显著性差异.结论:MRI对鼻咽癌颅底骨质破坏和咽后淋巴结的检出率高于CT.MRI使鼻咽癌的T分期升级,对临床分期有升级的趋势,而对N分期则无影响.     

Multiple pancreatic metastases from clear cell renal carcinoma: Diagnosis with chemical shift magnetic resonance imaging before surgery

We present a case in which multiple pancreatic tumours were diagnosed as metastatic clear cell renal carcinomas with chemical shift MRI (CSI) before surgery. Radiologists may be unable to recognize the loss of intensity on CSI macroscopically. We believe that it is useful to make subtraction images and calculate signal intensity on CSI, even if the lesions are multiple metastatic tumours.     

Magnetic resonance imaging features of an epidural spinal haemangioma

Isolated spinal epidural haemangioma without vertebral involvement is rare. We report a case of an epidural capillary haemangioma in the thoracic region and present the magnetic resonance findings, including contrast-enhanced features.     

A review of magnetic resonance imaging in spinal trauma

One hundred and ninety-five magnetic resonance (MR) images (1.5 Tesla) of 167 patients with neurological impairment following spinal trauma were reviewed. Acute cord injury produces central haemorrhagic necrosis that extends transversely and longitudinally with time and increased injury severity. Oedoma is more homogeneous, extensive and dominant in minimal lesions. Magnetic resonance appearances correlate with neurological status and outcome. Patients with MR evidence of cord blood had severe clinical lesions and failed to show useful clinical improvement. Patients with homogeneous ‘oedema’improved to useful function. Lesion signal inhomogeneity relates to a worse prognosis. The clinical level correlates closely with cord blood or signal in homogeneity but imprecisely with homogeneous oedema. Disc herniations require differentiation from epidural blood and venous engorgement, which are prominent with bone displacement. Magnetic resonance is recommended in incomplete cord syndromes and in cord injuries with no apparent fracture, particularly if clinically deteriorating. Chronic injury consists of cavitation, extensive gliosis, cord atrophy and leptomeningeal fibrosis. Progressive myelopathy may result from cystic or non-cystic intramedullary lesions. Cord cysts are common and cyst fluid signal should closely follow cerebrospinal fluid. Turbulent cyst fluid motion is commoner in larger cysts and may predict those cysts more prone to propagate. Progressive syrinxes show typical appearances, usually with transverse septa. Atrophy and propagating syrinxes usually take years to develop. Leptomeningeal cysts and spinal stenosis caused by bone displacement and accelerated adjacent disc disease may cause late deterioration. In progressive myelopathy following injury, surgically drainable cysts are clearly differentiable from cord gliosis and atrophy.     

Sonographic target sign and rim enhancement on magnetic resonance imaging in metastatic melanoma to the breast

We report a target sign on ultrasound and peripheral rim enhancement on gadolinium (Gd)‐enhanced MRI images in metastasis to the breast from melanoma. These classic signs, as reported in the liver (ultrasound target sign) and in primary breast cancers (Gd rim enhancement), are probably also of value in cases of metastatic lesions to the breast.     

Ultrasound and magnetic resonance imaging features in a patient with eosinophilic fasciitis

Eosinophilic fasciitis is a rare rheumatological disorder. We present a case of a young male patient who presented with this disease, and we describe how the findings on ultrasound and MRI correlated with the underlying pathology and assisted the diagnosis and the management of the patient.