Chondrosarcoma: MR imaging with pathologic correlation.

Magnetic resonance (MR) images of 21 surgically confirmed chondrosarcomas were retrospectively reviewed in conjunction with plain radiographs and computed tomographic scans and correlated with pathologic findings. The tumors appeared lobulated, and signal intensity, as analyzed visually (intermediate on T1-weighted, high on T2-weighted images), was similar for all lesions, regardless of pathologic type. Size of lesion was not an indicator of grade. The appearances of mesenchymal and dedifferentiated chondrosarcomas mimicked that of conventional chondrosarcoma. Extraskeletal chondrosarcoma was visualized as a lobulated soft-tissue mass. In all cases, MR imaging accurately depicted intraosseous and soft-tissue extent of tumor noted at surgery and pathologic examination. Histologic type or grade of chondrosarcoma generally cannot be characterized on the basis of visual analysis of signal intensity noted on routine MR images. However, MR imaging is excellent for exact delineation of tumor extent.     

Meniscal tears: pathologic correlation with MR imaging

Menisci from 12 autopsies and above-knee amputations were imaged with magnetic resonance (MR) at 1.5 T and then sectioned for gross and histologic examination. A histologic staging system was developed and showed a one-to-one correlation with corresponding grades of MR signal intensities. Histologic stages 1 and 2 represented a continuum of degeneration culminating in stage 3 fibrocartilaginous tears, seen most frequently in posterior-horn segments of the medial meniscus. Correlation of histologic stages with MR signal intensity allows for an improved diagnostic reading of MR images.     

MR imaging of intrahepatic cholangiocarcinoma with pathologic correlation

OBJECTIVE: The objective of this study was to determine the MR imaging features of intrahepatic cholangiocarcinoma. MATERIALS AND METHODS: MR images of 50 patients with pathologically proven intrahepatic cholangiocarcinoma were reviewed retrospectively. T1- and T2-weighted spin-echo images were obtained in all patients. Contrast-enhanced T1-weighted imaging was performed in 25 patients. Signal intensity and enhancement pattern of the tumors were correlated with pathology findings. The frequency of central hypointense regions on T2-weighted images and the intrahepatic bile duct dilatation of several other hepatic tumor types were investigated. Results were compared with imaging results of cholangiocarcinoma. RESULTS: On T2-weighted images, central hypo- and hyperintense regions were detected in tumors in 27 and 17 patients, respectively. Contrast-enhanced T1-weighted imaging revealed central hypointense areas exhibiting homogeneous, heterogeneous, and no enhancement in six, three, and five, respectively, of 14 patients. Regions of fibrosis displayed enhancement, whereas those of coagulative necrosis showed no enhancement. The signal intensity difference on T2-weighted images between the center and the edge of the tumor correlated well with the fibrotic ratio difference between those two areas corresponding to the MR image (Spearman's rank correlation test, r = 0.72, 95% confidence interval = 0.48-0.86). T2-weighted images revealed central hypointense regions in 16 of 34 instances of hepatic colorectal metastases. However, hypointensity was observed in only 26 of 234 other hepatic tumors. Intrahepatic bile duct dilatation was evident in 27 of 50 cases of cholangiocarcinoma but occurred in only a single case of 34 instances of hepatic colorectal metastases. CONCLUSION: The combination of the signal intensity on T2-weighted images and the enhancement pattern on contrast-enhanced T1-weighted images showed good correlation with the pathologic findings of cholangiocarcinoma. The occurrence of a central hypointense area on T2-weighted images is not pathognomonic; however, this finding, which reflects severe fibrosis, appears to be a characteristic marker of intrahepatic cholangiocarcinoma. The presence of intrahepatic bile duct dilatation may indicate cholangiocarcinoma, although it is difficult to differentiate cholangiocarcinoma from hepatic colorectal metastasis.     

MR imaging of soft-tissue hemangiomas: correlation with pathologic findings

Soft-tissue hemangiomas have been described in MR imaging, but a histopathologic correlation to better understand the MR appearance has not been reported. Five patients with intramuscular soft-tissue hemangiomas were imaged in orthogonal planes on a 1.5-T system with spin-echo (SE) short-TR/TE sequences (600/20) and long-TR/TE sequences (2500/20-80). Complete intact surgical specimens were obtained, and gross and histopathologic findings were compared with MR findings. A striated-septated configuration with a high signal intensity on long-SE sequences (TE greater than 75 msec) correlated with endothelial-lined vascular channels separated by fibrous and/or fatty linear strands. An awareness of the morphologic MR pattern of soft-tissue hemangiomas may aid in recognition of these lesions.     

子宫腺肌症的MRI表现及其病理学对照研究

目的：研究MRI在子宫腺肌症诊断中的应用价值。方法：对30例子宫腺肌症患者行矢状面快速自旋回波（Turbo SE)T1WI,T2TI,T1和T2频谱预饱和翻转恢复序列（T1SPIR和T2SPIR）扫描，必要时辅以横断面或冠状面扫描。所有病例均经手术病理证实。结果：弥漫型子宫腺肌症12例，在T2WI上表现为子宫结合带弥漫性增厚，厚度10－35mm，平均18mm，6例病变呈均匀低信号；6例病变内有散在的点高信号区，其中5例在T1WI仍表现为高信号。局限型子宫腺肌症（腺肌瘤）18例共23个病灶，在T2WI上表现为肌层内卵圆形，不规则形或类圆形肿块，呈与结合带信号相近的低信号，直径2．0－7.5cm，平均3.9cm，除1个病灶与周围肌组织有较清楚的界限外，其余病灶均与周围肌组织分界不清，15个病灶内有散在点状高信号区，其中12个在T1WI上也呈高信号，MRI上弥漫增厚的结合带和局限性低信号肿块，病理学上为异位内膜岛周围增生肥大的平滑肌，其内散在的点状信号区异异位内膜岛。仅在T2WI表现高信号的为示出血的内膜岛，在T1WI和T2WI均为高信号的为出血的内膜岛。结论：MRI是诊断子宫腺肌症的优越的无创性检查方法，T2WI最佳扫描序列，T2WI与T1WI，T1SPIR，T2SPIR4种序列相结合可大大提高断诊准确率。     

Hypointense renal cell carcinoma: MR imaging with pathologic correlation

In two pathologically documented cases of renal cell carcinoma, the appearance of the tumors at magnetic resonance (MR) imaging was markedly hypointense relative to normal renal parenchyma on both T1- and T2-weighted spin-echo images. Pathologic examination of both tumors revealed diffuse iron scattered throughout the tumors. The paramagnetic effect of the iron may account for this unusual hypointense appearance at spin-echo imaging, independent of pulse sequence.     

Thyroid masses: MR imaging and pathologic correlation

The authors explored the capability of high-field-strength surface coil magnetic resonance (MR) imaging in disclosing the gross pathologic characteristics of thyroid masses (especially pseudocapsular and hemorrhagic degeneration). Twenty-four patients were examined, including 12 with papillary carcinoma, eight with adenoma, and four with adenomatous goiter. All patients underwent surgery within 2 days after MR imaging. Specimens were cut and correlated directly with MR images. The appearance of the pseudocapsule was classified into four types: A, intact and even thickness around the tumor; B, only partially present or even absent; C, intact but with uneven thickness; D, partially destroyed by tumor. MR imaging findings corresponded precisely with those of gross pathologic examination in all cases but four of adenoma. Type A pseudocapsules were found only in adenoma and type D only in papillary carcinoma. Although the number of cases in the series was limited, the authors conclude that MR images reflect gross pathologic findings well and that some characteristic findings are suggestive of benign or malignant disease.     

Prostate cancer: correlation of MR imaging and MR spectroscopy with pathologic findings after radiation therapy-initial experience

PURPOSE: To prospectively evaluate magnetic resonance (MR) imaging and MR spectroscopy for depiction of local prostate cancer recurrence after external-beam radiation therapy, with step-section pathologic findings as the standard of reference. MATERIALS AND METHODS: Study received institutional approval, and written informed consent was obtained. Study was compliant with Health Insurance Portability and Accountability Act. Sextant biopsy, digital rectal examination, MR imaging, MR spectroscopy, and salvage radical prostatectomy with step-section pathologic examination were performed in nine patients with increasing prostate-specific antigen levels after external-beam radiation therapy. MR imaging criterion for tumor was a focal nodular region of reduced signal intensity at T2-weighted imaging. MR spectroscopic criteria for tumor were voxels with choline (Cho) plus creatine (Cr) to citrate (Cit) ratio ([Cho + Cr]/Cit) of at least 0.5 or voxels with detectable Cho and no Cit in the peripheral zone. Sensitivity and specificity of sextant biopsy, digital rectal examination, MR imaging, and MR spectroscopy were determined by using a prostate sextant as the unit of analysis. For feature analysis, MR imaging and MR spectroscopic findings were correlated with step-section pathologic findings. RESULTS: MR imaging and MR spectroscopy showed estimated sensitivities of 68% and 77%, respectively, while sensitivities of biopsy and digital rectal examination were 48% and 16%, respectively. MR spectroscopy appears to be less specific (78%) than the other three tests, each of which had a specificity higher than 90%. MR spectroscopic feature analysis showed that a metabolically altered benign gland could be falsely identified as tumor by using MR spectroscopic criteria; further analysis of MR spectroscopic features did not lead to improved MR spectroscopic criteria for recurrent tumor. CONCLUSION: In summary, MR imaging and MR spectroscopy may be more sensitive than sextant biopsy and digital rectal examination for sextant localization of cancer recurrence after external-beam radiation therapy.     

白血病骨髓移植的MRI研究

目的 研究ＭＲＩ对白血病骨髓移植（ＢＭＴ）患者骨髓变化的评估作用和价值。方法 共２０例白血病ＢＭＴ患者,分别在ＢＭＴ前后行ＳＥ序列Ｔ１ＷＩ和脂肪抑制成像;并测量腰椎骨髓Ｔ１弛豫时间。结果 １７例ＢＭＴ后骨髓在Ｔ１ＷＩ上信号强度升高复发率５．８８％;３例信号无变化者,复发率６６．７０％;两组间复发率差异具有显著性意义（Ｐ〈０．０５）;ＢＭＴ后腰椎骨髓Ｔ１值低于正常值（Ｐ〈０．０５）;与ＢＭＴ前相比,     

Regenerating nodules of liver cirrhosis: MR imaging with pathologic correlation

To determine the pathologic basis for low-intensity nodules seen on MR images of the liver in patients with cirrhosis, we obtained spin-echo and gradient-echo MR images in 20 cirrhotic patients in whom partial hepatectomies were subsequently performed for hepatocellular carcinoma. Low-intensity liver nodules were shown on gradient-echo and spin-echo images in eight patients. Pathologic study of the liver in these patients showed that these nodules were regenerating nodules containing hemosiderin. Low-intensity nodules were seen only on T2-weighted spin-echo images in four other patients. Microscopic examination of the liver in these patients showed regenerating nodules without hemosiderin deposits. Broad fibrous septa containing vascular spaces were present in two of these four patients. These results suggest that regenerating nodules containing hemosiderin or those that are surrounded by vascular fibrous septa are visible on MR images as low-intensity nodules and that gradient-echo images are useful in demonstrating nodules with hemosiderin.     

Primary sclerosing cholangitis: MR imaging findings with pathologic correlation.

OBJECTIVE: The purpose of this study was to evaluate MR imaging findings of primary sclerosing cholangitis, to compare them with histopathologic findings, and to determine if these findings help differentiate primary sclerosing cholangitis from other disorders that result in end-stage liver disease. MATERIALS AND METHODS: MR imaging was performed in 40 patients (27 men, 13 women; age range, 13-72 years; mean, 47 years) with primary sclerosing cholangitis over a 9-year period. In 16 patients who underwent orthotopic hepatic transplantation and in seven patients who underwent needle biopsy, correlation was made between MR imaging and pathologic findings. RESULTS: Focal signal changes in the liver parenchyma were seen on T2-weighted images as peripheral wedge-shaped zones of increased signal intensity in 29 patients (72%), as a reticular pattern in 15 patients (38%), and as periportal edema in 16 patients (40%). Lobar atrophy involved the right lobe in three patients (8%) and the left lobe in 11 patients (28%); hypertrophy of the caudate lobe was seen in nine patients (23%). Features of portal hypertension were seen in 14 patients (35%). Histologic assessment showed zones of segmental atrophy and scarring on the periphery of the liver. CONCLUSION: Peripheral wedge-shaped areas of high T2 signal intensity and dilatation of bile ducts are characteristic MR features of primary sclerosing cholangitis. Pathologic correlation suggests that these features may be related to underlying perfusion changes and bile duct inflammation in patients with primary sclerosing cholangitis.     

肝腺瘤:MRI影像学表现与病理亚型的相关性研究

目的研究肝腺瘤的MRI影像学表现与病理亚型的相关性。材料与方法本回顾性研究获得伦理委员会批准。免除受试者知情同意。由2名放射学专家对61个病灶(48例病人,中位年龄36岁)分别独立进行MRI分析。2名观察者就病变的形态和信号特点的影像特征达成共识。所     

MR imaging of endometrial stromal sarcoma: correlation with pathologic findings.

OBJECTIVE: This study describes MR imaging of eight patients with endometrial stromal sarcoma and correlates the imaging findings with histopathologic findings. To our knowledge, the radiologic findings of this entity have not been reported in the literature. CONCLUSION: Endometrial stromal sarcoma typically presents with extensive myometrial involvement, which is either sharply demarcated or diffusely infiltrative. Bands of low signal intensity are observed within the areas of myometrial involvement on T2-weighted images. These bands correspond to the preserved bundles of myometrium on pathologic examination. Tumor extension along the vessels or ligaments is another characteristic of MR imaging of endometrial stromal sarcoma.     

Brachial plexus: correlation of MR imaging with CT and pathologic findings

Thirty-two patients with symptoms referable to the brachial plexus were evaluated with magnetic resonance (MR) imaging. Sixteen patients had undergone concurrent computed tomography (CT). MR imaging demonstrated normal findings in 16, 12 neoplasms, three cases of trauma, and one case of possible neural edema. Of the 16 patients with normal findings on MR images, eight had CT scans that were also normal. In one patient, MR images showed that the "mass" seen on CT was actually a tortuous blood vessel. In six of the 12 cases of neoplasm in which CT scans were available, MR imaging revealed more extensive disease. In the other six cases of tumor, MR imaging provided sufficient clinical information to obviate the need for CT or any other imaging modality. MR imaging provided definitive diagnoses in the three cases of trauma without further imaging. In one patient with paresthesia, MR imaging showed high signal intensity of the nerves on T2-weighted images, which was compatible with neural edema. A concurrent CT scan was normal.     

MR imaging of uterine carcinoma: correlation with clinical and pathologic findings

Thirteen patients with clinical stages I and II endometrial carcinoma were examined with magnetic resonance (MR) imaging before surgery. Depth of invasion and stage of disease were assessed, and the results were compared with those from MR images of the surgical specimens and pathologic findings. Staging with MR imaging was accurate in 11 of 13 patients (85%). Our results agree with previous reports that MR imaging is an accurate, noninvasive method of assessing depth of myometrial invasion and cervical involvement. We anticipate that MR imaging will have an increasing role in treatment of patients with endometrial carcinoma.     

MR imaging in fibromatosis: results in 26 patients with pathologic correlation

Fibromatoses are a diverse group of soft-tissue lesions that have been inconsistently categorized and treated. The purpose of our study was to establish the range of appearances of fibromatoses on MR images and perform a pathologic correlation to explain the variable signal-intensity patterns. During a 3-year period, 26 patients with deep fibromatoses were examined with MR. The MR images were evaluated for signal-intensity characteristics, and findings were correlated retrospectively with the pathologic diagnoses. The results showed that the MR appearance of fibromatoses is similar to that of other soft-tissue lesions, and the signal intensities vary greatly from lesion to lesion and within lesions themselves. The fibromatoses were either hyperintense, isointense, hypointense, or of mixed signal intensity relative to adjacent skeletal muscle. The hypointense areas appear to be zones of hypocellularity and dense collagen deposition. Microscopically all of the lesions invaded adjacent structures, but the MR appearances of the margins varied and were judged to be well demarcated (n = 14), intermediate (n = 5), or poorly demarcated (n = 6). Our experience shows that fibromatoses have a variable MR appearance no different from that of other soft-tissue lesions, and this variability reflects the composition and cellularity of the lesions.