A case of fallopian tube carcinoma: successful preoperative diagnosis with MR imaging.

We report a case of fallopian tube carcinoma, successfully diagnosed preoperatively. The patient was a 64-year-old woman. Transvaginal sonography and computed tomography showed a cystic and solid tumor on the left side of the uterus, suggesting ovarian cancer. The tumor was, however, suspected to be a fallopian tube carcinoma on MR imaging. MR images showed a solid mass surrounded by a tube-shaped cystic part. At surgery, a solid and cystic tumor was found in the left fallopian tube. MR imaging may be useful to assist in the diagnosis of fallopian tube carcinoma.     

Pelvic heterotopic ossification: MR imaging characteristics.

PURPOSE: To evaluate the magnetic resonance (MR) signal intensity characteristics of pelvic heterotopic ossification (HO) in various stages of maturation. MATERIALS AND METHODS: Thirty-six patients with HO proved at computed tomography (CT) (n = 17) or radiography (n = 19) who underwent 1.5-T pelvic MR imaging within 3 months were included. HO was defined at CT or radiography as grade 1, fluid attenuation without calcification at CT; grade 2, calcification; grade 3, immature ossification; or grade 4, mature ossification. The location and MR signal intensity of all HO sites were noted. RESULTS: HO was determined to be grade 1 at 20 of 141 sites, grade 2 at 39, grade 3 at 30, and grade 4 at 52. With increasing HO grade, the following findings were observed: (a) decreasing T2 signal intensity (grade 1, 70%; grade 2, 58%; grade 3, 44%; grade 4, 4%), (b) increasing fat and cortical bone signal intensity at T1-weighted imaging (grade 1, 0%; grade 2, 3%; grade 3, 13%; grade 4, 86%), and (c) decreasing contrast enhancement (from 100% for grade 1 to 20% for grade 4). Fifteen (88%) patients with CT correlation had HO in the anatomic area of the trochanteric or iliopsoas bursa (55 [60%] of 91 sites). CONCLUSION: With progressive maturity of HO, T2 signal intensity and contrast enhancement decrease, but fat and cortical bone-equivalent signal intensity increases.     

MR imaging characteristics of hepatic tumors

There is no doubt that radiologists play an increasingly important role in the detection of focal liver lesions, and in the evaluation of persistent or recurrent malignant disease after treatment. The characterization of focal liver lesions depends on the clinical integration of the information generated by different radiologic techniques. Most often, MR imaging is quite effective in liver tumor characterization. Our purpose is to provide an overview of the MR characteristics of the most commonly encountered liver tumors and their differential diagnosis, with the most accepted reliable proof of the lesion type in a clinical environment. Radiologists must know the level of confidence they can reach in a given diagnosis, and the influence that this diagnosis has in the patient's management. With this knowledge, radiologists decide whether to leave or follow-up the lesion, perform tissue samples, or carry out therapeutic procedures. Received 28 September 1995; Revision received 22 April 1996; Accepted 26 April 1996     

MR imaging characteristics of pilomyxoid astrocytomas

BACKGROUND AND PURPOSE: Pilomyxoid astrocytoma (PMA) is a recently described tumor that typically occurs in the chiasmatic-hypothalamic region in young children and has unique histopathologic and clinical characteristics. These tumors have been previously diagnosed as pilocytic astrocytoma (PA). PMA appears to have a higher rate of recurrence and CSF dissemination than typical PA. METHODS: We analyzed MR findings in four patients with PMA and compared them with those of typical chiasmatic-hypothalamic PA. RESULTS: MR findings of PMA were chiasmatic or hypothalamic enhancing solid tumor with hydrocephalus, highly homogeneous T2 signal intensity that extended into the deep white and gray matter, and CSF dissemination. CONCLUSION: Larger series are needed before the MR imaging findings of chiasmatic or hypothalamic enhancing solid tumor with hydrocephalus, highly homogeneous T2 signal intensity extending into the deep white and gray matter, and CSF dissemination can be used in the differential diagnosis of such tumors.     

MR imaging characteristics of protoplasmic astrocytomas

Introduction  

Protoplasmic astrocytomas are a poorly recognized and uncommon subtype of astrocytoma. While usually categorized with other low-grade gliomas, there is literature to suggest that protoplasmic astrocytomas have differences in biology compared to other gliomas in this group. This paper presents the MR imaging characteristics of a series of eight protoplasmic astrocytomas.     

Lymphomas: MR imaging contrast characteristics with clinical-pathologic correlations

Mean pixel intensity ratios, contrast parameters, and T1-T2 cross products relative to fat and muscle were derived from T1-weighted and T2-weighted images obtained at 1.5 T in 32 patients with non-Hodgkin lymphomas and 20 with Hodgkin disease. Lymphomas were relatively homogeneous: Only 6% of the lesions had broad, bimodal, or skewed distributions of pixel intensities that could be attributed to intrinsic heterogeneity. On average, lymphomas were hypointense to fat and slightly hyperintense to muscle in T1-weighted images but isointense to fat and hyperintense to muscle in T2-weighted images. Low-, intermediate-, and high-grade non-Hodgkin lymphomas had identical imaging characteristics. The most striking and significant result was the greater brightness of lymphomas with dense fibrosis in T2-weighted images, which explains the trend toward greater brightness of Hodgkin disease than that of non-Hodgkin lymphomas and greater brightness of lymphomas in the mediastinum than of lymphomas in other locations. Neither a contrast parameter nor the T1-T2 cross product added information not evident with the use of simple mean pixel intensity ratios.     

Tuberous sclerosis: characteristics at CT and MR imaging

Computed tomography (CT) and magnetic resonance (MR) imaging findings were reviewed in 26 patients with tuberous sclerosis. All patients underwent CT; 16 patients underwent both. The CT features included subependymal nodules in 25 of 26 patients (96%) and calcifications in 23 of 26 (88%). Parenchymal hamartomas (cortical tubers) were seen in 23 of 26 patients (88%). These lesions had less attenuation than surrounding brain in 16 of 26 patients (62%) and were calcified in 14 of 26 patients (54%). Contrast enhancement of a lesion, indicating a subependymal giant cell astrocytoma, occurred in three of 26 patients (12%). The MR imaging characteristics included subependymal nodules (periventricular nodules) of intermediate signal intensity in ten of the 16 patients (63%). Parenchymal hamartomas, demonstrated in 15 of the 16 patients (94%), usually exhibited long T1 and T2 relaxation characteristics. The pattern was noted to be reversed in the two newborn patients (13%). One parent demonstrated a forme fruste at CT but had a normal MR image.     

Morphologic characteristics of subcortical heterotopia: MR imaging study

BACKGROUND AND PURPOSE: Gray matter heterotopia have been divided into three groups based on clinical and imaging characteristics: subependymal, subcortical, and band heterotopia. Nonetheless, subcortical heterotopia can have variable morphologic findings. The purpose of this study was to perform a morphologic analysis of a series of cases of subcortical heterotopia based on MR images, to correlate the morphologic appearance with clinical characteristics, and to speculate about the embryologic implications of our results. METHODS: The MR imaging studies and clinical records of 24 patients with subcortical heterotopia were retrospectively reviewed. The morphologic findings of the heterotopia were recorded along with presence and type of associated malformations. These results were correlated with available data on development and neurologic status. RESULTS: Analysis revealed that, in six cases, the heterotopia were composed exclusively of multiple nodules, in 13, they appeared primarily as curvilinear ribbons of cortex extending into the white matter, and in five, they had deep nodular regions with curvilinear areas more peripherally. All of the curvilinear regions were contiguous with the cerebral cortex in at least two locations. In eight cases, curvilinear heterotopia contained curvilinear areas of flow void that were thought to be blood vessels; in 10, they contained fluid resembling CSF. No difference in developmental or neurologic manifestations was noted among patients with heterotopia of different morphologic appearances. CONCLUSION: Subcortical heterotopia can have nodular or curvilinear morphologic appearances. Although no difference was found in the clinical conditions of the patients with differing morphologic appearances, additional analysis of these patients or studies of animal models of these malformations may further our understanding of normal and abnormal brain development.     

Wallstent metallic biliary endoprosthesis: MR imaging characteristics.

Image quality and safety of magnetic resonance (MR) imaging were evaluated in vitro and in eight patients with the most commonly employed metallic biliary endoprosthesis. In vitro, the stent produced no tip deflection at 0.6 or 1.5 T. Trace magnetic susceptibility artifact, similar to artifact from a column of air, paralleled the stent. In patients, image degradation was minimal with conventional pulse sequences. Middle-field-strength spin-echo images revealed minimal artifacts indistinguishable from those produced by pneumobilia.     

Liver metastases from pancreatic adenocarcinoma: MR imaging characteristics

PURPOSE: To describe the magnetic resonance imaging spectrum of appearances of liver metastases from pancreatic ductal adenocarcinoma. MATERIALS AND METHODS: We retrospectively evaluated the MRI exams performed between July 1996 and August 2001 in all patients who had liver metastases from pancreatic adenocarcinoma and histopathologic diagnosis from either the primary pancreatic tumor, liver metastases, or both. Sixteen patients were included in the study. All MR studies were performed at 1.5 T with a standard protocol including T1- and T2-weighted images and serial post-gadolinium spoiled gradient echo (SGE) images. Location, size, number, signal characteristics on T1- and T2-weighted images, and pattern of enhancement on serial gadolinium-enhanced SGE images were assessed. RESULTS: The diameter of metastases ranged from a few millimetres to 4 cm, and 12 patients (75%) had only lesions of 1.5 cm or less. Capsular-based liver metastases were found in 13 patients (81%) and three patients had only capsular-based lesions with a diameter under 1.5 cm. Hypervascular lesions were found in six patients (38%) and hypovascular lesions in 10 patients (62%). Perilesional enhancement was present in 10 patients (62%), with six patients (38%) having ring perilesional enhancement and eight patients (50%) having wedge-shaped perilesional enhancement. CONCLUSION: On MR imaging, hepatic metastases from pancreatic adenocarcinoma show a range of enhancement patterns. Hypervascular metastases are not rare. Capsular based distribution, small diameter, and perilesional enhancement are common features. This retrospective study describes the MR imaging spectrum of appearances of liver metastases from pancreatic adenocarcinoma in patients with histopathologic confirmation of the diagnosis.     

Endovaginal sonographic diagnosis of dilated fallopian tubes

Twelve cases of fallopian tube dilatation were diagnosed in 10 patient by using endovaginal sonography. The diagnosis was confirmed by surgery in seven patients and by hysterosalpingography in three. A tubular shape was present in every case. Other sonographic features included a well-defined echogenic wall, a folded configuration, and linear echoes protruding into the tube lumen. Dilated tubes were distinguished from bowel loops by a lack of peristaltic activity and from pelvic veins by a lack of moving low-level echoes on real-time sonography. We conclude that the findings of dilated fallopian tubes on endovaginal sonography are sufficiently characteristic to allow the diagnosis to be made with this technique.     

桥小脑角区髓母细胞瘤的 MRI 表现

目的：分析桥小脑角区(CPA)髓母细胞瘤的 MRI 特点,提高该病的诊断率。方法回顾性分析5例经手术病理证实的发生于 CPA 髓母细胞瘤的 MRI 表现特点及病理特征。结果5例髓母细胞瘤中4例见囊变,且均位于肿瘤的边缘,1例为完全实性肿块。肿瘤实性部分 T1 WI 呈低、稍低信号,T2 WI 呈稍高或高信号为主混杂信号。2例行 DWI 扫描呈高信号。增强后强化程度多样。5例肿瘤均引起桥脑及四脑室受压,2例邻近基底脑膜强化,2例出现瘤周水肿。结论MRI 可显示 CPA 髓母细胞瘤肿瘤的范围、继发改变及与周围组织的关系。     

三阴性乳腺癌的MRI影像学特点分析

目的：探讨三阴性乳腺癌（TNBC）的特征性MRI影像学表现,并与非三阴性乳腺癌比较。方法：分析有完整资料的90例乳腺癌,所有病例术前均行乳腺MRI检查并经手术或病理证实,其中三阴性乳腺癌23例,非三阴性乳腺癌67例。纳入分析的病灶MRI表现包括病灶形状、边界、大小、数目、内部强化、时间信号强度曲线（TIC）类型和表观扩散系数（ADC）,并将MRI表现与病理结果作对照。结果：与非三阴性乳腺癌相比,TNBC在MRI上大多表现为边缘光整、环状强化及更低的ADC值。而在患者年龄,病灶形状、大小、数目及TIC上,差异无统计学意义（P〉0.05）。结论：乳腺癌MRI表现中病灶边界光整、增强时环状强化、较低的ADC值对诊断TNBC具有一定参考价值。     

Osteomyelitis: characteristics and pitfalls of diagnosis with MR imaging

Prospective and retrospective magnetic resonance (MR) imaging (0.35-T) interpretations were compared with final diagnoses in 110 patients suspected to have osteomyelitis. Diagnostic criteria of dark marrow on T1-weighted images and bright marrow on short-tau inversion-recovery images yielded a prospective sensitivity of 98% and a prospective specificity of 75%. Sixty percent of uncomplicated septic joint effusions demonstrated abnormal marrow signal intensity that was mistaken for osteomyelitis. Retrospective review revealed that overall specificity could be improved to 82% without loss of sensitivity if increased marrow signal intensity on T2-weighted images were included as an additional criterion. Specificity may be further increased by use of knowledge of morphologic patterns that distinguish various forms of osteomyelitis. Ten patients (9%) had potential pitfall diagnoses (eg, fracture, infarction, healed infection) that mimic osteomyelitis. MR imaging can be sensitive and specific for osteomyelitis if characteristic appearances and pitfall diagnoses are incorporated into the diagnostic criteria.