Spinal MR findings in continuous epidural analgesia without infection

BACKGROUND AND PURPOSE: Spinal epidural abscesses are major complications of epidural anesthesia, and their MR features have been reported. In patients receiving continuous infusion via an epidural catheter, MR findings may mimic those of spinal epidural abscess in the absence of infection. The purpose of this study was to assess the spinal MR findings associated with continuous epidural anesthesia. METHODS: Spinal MR findings in five consecutive patients receiving continuous epidural anesthesia were retrospectively evaluated. Axial and sagittal T1- and T2-weighted spin-echo and contrast-enhanced fat-suppressed T1-weighted spin-echo images were obtained. Infection was ruled out on microbiologic analysis three patients and on follow-up in two. Each lesion was evaluated for its MR signal intensity, location, extent, delineation, and enhancement pattern. In three patients, follow-up MR imaging was performed within 5-150 days, and the images were compared. RESULTS: Posterior epidural lesions were identified in all five patients. The lesions were isointense to hypointense relative to the spinal cord on T1-weighted images, isointense relative to CSF on T2-weighted images, and well enhanced on enhanced T1-weighted images. The anomalous enhancement involved two to seven vertebral bodies. In one patient, the enhanced lesion slightly compressed the spinal cord. On follow-up MR imaging, the epidural lesions decreased in two patients and did not change in one. CONCLUSION: Continuous epidural anesthesia can result in MR findings similar to those of epidural abscess, even in the absence of infection.     

Intradural schwannomas of the spine: MR findings with emphasis on contrast-enhancement characteristics.

Intradural extramedullary schwannomas are nerve sheath neoplasms that consist of focal proliferations of Schwann cells involving a spinal nerve. We reviewed the MR findings in seven patients with pathologically proved intradural schwannomas. The contrast-enhancement characteristics on MR images were determined and compared with the histologic features of the tumor. Six lesions were variably hyperintense on T2-weighted images and one was uniformly hypointense compared with the signal intensity of the spinal cord. Signal on T1-weighted images ranged from hypointense to isointense. All seven tumors showed heterogeneous enhancement; in five, the enhancement involved only the periphery of the lesion. The pattern of enhancement did not correlate with the signal characteristics noted on unenhanced T1- and T2-weighted images. Pathologically, hyaline thickening of vessel walls and cyst formation were prevalent in the peripherally enhancing lesions. However, enhancement did not correlate with the relative proportion of Antoni type A and type B tissue. Recognition of the MR characteristics of intradural extramedullary schwannomas may be helpful in the differential diagnosis of spinal tumors. In particular, peripheral contrast enhancement of an intradural extramedullary tumor on MR images should suggest the diagnosis of schwannoma.     

脊髓血管母细胞瘤的MRI表现

目的评估脊髓血管母细胞瘤的MRI表现。资料与方法回顾性分析7例经手术病理证实的脊髓血管母细胞瘤的MR／表现。7例均行常规MR扫描,应用T1、T2加权序列作轴面、矢状面扫描,且均应用T1WISE作轴面、矢状面、冠状面增强扫描。结果7例肿瘤在T1WI上呈等信号、低信号或等、低混杂信号,在T2WI上呈高信号或混杂信号,增强后均一或不均一强化。其中5例伴有脊髓空洞,4例可见血管流空效应,2例伴有瘤周水肿。结论脊髓血管母细胞瘤的MRI表现具有特征性。MRI还有利于明确肿瘤的位置和范围,以及外科治疗计划的制定。     

MRI of hemangioblastoma in the conus medullaris.

Hemangioblastoma of the conus medullaris with MRI has not been reported before. A 75-year-old man had a history of falling due to weakness of his left lower limb. MRI revealed a well-defined oval mass in the conus medullaris. The tumor had an isointense signal relative to spinal cord on T1-weighted images, hyperintense signal areas intermixed with punctate spots of hypointensity on T2-weighted images, and heterogeneous obvious enhancement on gadolinium-enhanced T1-weighted images. Associated abnormally tortuous vessels were noted in the dura proximal to the tumor. Histological findings were compatible with the diagnosis of hemangioblastoma. Hemangioblastoma should be included in the differential diagnosis in patients with an enhancing tumor and adjacent engorged vessels of the spinal cord.     

MR findings in eosinophilic infiltration of the liver

OBJECTIVE: This study describes the findings of magnetic resonance imaging (MRI) of focal eosinophilic infiltration of the liver. METHODS: Contrast-enhanced MR images of 8 patients with focal hepatic eosinophilic infiltration were reviewed retrospectively. We evaluated the signal intensity of focal lesions in T1-weighted and T2-weighted images and the pattern of enhancement in a dynamic contrast study. RESULTS: A total 22 focal hepatic lesions were observed; the lesions were isointense (55%) or hypointense (45%) on T1-weighted images and isointense (14%) or hyperintense (86%) on T2-weighted images. The arterial phase of the contrast study revealed 11 hyperintense lesions (50%). During the portal and delayed phases, 18 (82%) and 17 lesions (77%) were hyperintense, respectively. CONCLUSION: The focal eosinophilic infiltrations showed homogeneous enhancement in the portal and delayed phases in the dynamic contrast MR study. These findings should help to distinguish focal eosinophilic infiltration, especially from metastasis in patients with malignancy.     

Solitary fibrous tumor in the buccal space: MR findings with pathologic correlation.

We report MR findings in a case of a solitary fibrous tumor involving the buccal space in a middle-aged man. On MR images, most of the mass was isointense and hyperintense to the muscle on T1- and T2-weighted images, respectively, and showed homogeneously strong enhancement on contrast-enhanced T1-weighted images. The medial peripheral portion, which was isointense on T2-weighted images and showed less enhancement on contrast-enhanced T1-weighted images, corresponded to the hypocellular and collagenous sclerotic area on pathologic correlation.     

MR imaging findings of neurosarcoidosis of the gasserian ganglion: an unusual presentation

We report the MR imaging findings of an unusual case of neurosarcoidosis of the gasserian ganglion associated with trigeminal neuralgia. No other neurological or extraneurological localization was found. Magnetic resonance imaging demonstrated a mass in the Meckel's diverticulum that was isointense on T1-weighted images and hypointense on T2-weighted images. Gadolinium-enhanced MR imaging showed heterogeneous enhancement. Although rare, sarcoid infiltration of the gasserian ganglion must be considered in the differential diagnosis of an isolated mass in this localization in patients with trigeminal neuralgia. Electronic Publication     

Spinal intradural capillary hemangioma: MR findings

We report a case of a spinal intradural capillary hemangioma. On MR images, a well-circumscribed intradural mass was detected at the T8-T9 level. The signal intensity of the mass relative to the spinal cord was isointense on T1-weighted images, hyperintense on T2-weighted images, and showed homogeneous, strong enhancement on contrast-enhanced T1-weighted images. The mass had both extramedullary and intramedullary components.     

MRI findings in spinal subdural and epidural hematomas

BACKGROUND: Spinal hematomas are rare entities that can be the cause of an acute spinal cord compression syndrome. Therefore, an early diagnosis is of great importance. PATIENTS AND METHODS: From 2001 to 2005 seven patients with intense back pain and/or acute progressive neurological deficit were studied via 1.5 T MRI (in axial and sagittal T1- and T2-weighted sequences). Follow-up MRI was obtained in six patients. RESULTS: Four patients showed the MRI features of a hyperacute spinal hematoma (two spinal subdural hematoma [SSH] and two spinal epidural hematoma [SEH]), isointense to the spinal cord on T1- and hyperintense on T2-weighted sequences. One patient had an early subacute SEH manifest as heterogeneous signal intensity with areas of high signal intensity on T1- and T2-weighted images. Another patient had a late subacute SSH with high signal intensity on T1- and T2-weighted sequences. The final patient had a SEH in the late chronic phase being hypointense on T1- and T2-weighted sequences. DISCUSSION: MRI is valuable in diagnosing the presence, location and extent of spinal hematomas. Hyperacute spinal hematoma and the differentiation between SSH and SEH are particular diagnostic challenges. In addition, MRI is an important tool in the follow-up in patients with conservative treatment.     

Liver adenomatosis: classification of MR imaging features and comparison with pathologic findings

PURPOSE: To retrospectively compare the clinical manifestation and magnetic resonance (MR) imaging features of liver adenomatosis with pathologic findings. MATERIALS AND METHODS: This study had institutional review board approval, and informed consent was waived. Twenty patients were classified on the basis of pathologic findings into three groups: those with a steatotic, those with a peliotic, and those with a mixed (steatotic and peliotic) form of liver adenomatosis. MR images were reviewed in consensus by two abdominal radiologists, and findings were compared with the pathologic classification. Statistical evaluation was performed with the Student t test. RESULTS: All patients were women (mean age, 39 years +/- 10 [standard deviation]). Lesions of the steatotic form (n = 7) showed (a) a mean diameter of 6.3 cm +/- 1.7, (b) slightly hyperintense signal on T2-weighted images, (c) hyper- or isointense signal on T1-weighted images with a signal dropout with fat suppression sequences, and (d) moderate enhancement at the arterial phase with no delayed enhancement. Lesions of the peliotic form (n = 7) showed (a) a somewhat larger size (8.3 cm +/- 3.6), (b) markedly hyperintense signal on T2-weighted images, (c) iso- or hyperintensity on T1-weighted images with no signal dropout with fat suppression sequences, and (d) strong arterial enhancement and persistent enhancement at the portal and delayed phase. Lesions of the mixed form (n = 6) included a combination of imaging features of the steatotic and peliotic forms. Lesions, however, were significantly larger in the mixed form than in the steatotic form (10.3 cm +/- 4, P < .05). CONCLUSION: There are three patterns of MR imaging features of liver adenomatosis that are associated with three pathologic forms (steatotic, peliotic, and mixed).     

Rhabdomyolysis: magnetic resonance imaging and computed tomography findings

OBJECTIVE: Our purpose was to describe the magnetic resonance (MR) imaging and computed tomography (CT) findings in patients with rhabdomyolysis. METHODS: The medical records and imaging studies of 10 patients (5 males, 5 females; age range, 14-60 years; mean age, 28.3 years) with rhabdomyolysis were retrospectively reviewed. Magnetic resonance imaging was available in 9 patients and CT in 2 patients. RESULTS: Two distinct imaging types of rhabdomyolysis were observed. For type 1 rhabdomyolysis (n = 2), the affected muscles revealed homogeneously isointense to hyperintense on T1-weighted, homogeneously hyperintense on T2-weighted and short-tau inversion recovery (STIR) images, and homogeneously enhanced on contrast-enhanced MR images. For type 2 rhabdomyolysis (n = 8), the affected muscles revealed homogeneously or heterogeneously isointense to hyperintense on T1-weighted images, heterogeneously hyperintense on T2-weighted and STIR images, heterogeneously hypodense on CT images, and rim enhanced on contrast-enhanced MR and CT images with the presence of a specific presentation, named as the "stipple sign." CONCLUSIONS: Rhabdomyolysis is a clinical and biochemical syndrome comprising 2 distinct imaging types. Homogeneous signal changes and enhancement in the affected muscles advocate type 1 rhabdomyolysis. The stipple sign is helpful in demonstrating the areas of myonecrosis in type 2 rhabdomyolysis and, together with clinical and laboratory presentations, in reaching the correct diagnosis.     

Carcinoid tumor of the ampulla of Vater. Magnetic resonance imaging findings

Carcinoid tumors arising from the ampulla of Vater are rare, and their magnetic resonance (MR) imaging findings have not been reported in the literature to date. We report a case of carcinoid tumor of the ampulla of Vater and discuss the characteristic MR imaging findings. The tumor was isointense relative to the muscle on both the T1- and T2-weighted images with heterogeneous enhancement after gadolinium administration. Both the common bile and the pancreatic ducts were dilated on the MR cholangiopancreatography.     

Imaging study of ossifying fibroma with associated aneurysmal bone cyst in the paranasal sinus

Objective

To determine the CT and MR imaging features of ossifying fibroma with aneurysmal bone cyst of the paranasal sinus.

Materials and methods

We retrospectively reviewed 15 patients with histopathology-proven ossifying fibromas with aneurysmal bone cysts in the paranasal sinus. All 15 patients underwent CT and MR imaging. The following imaging features were reviewed: location, shape, margin, CT findings, and MR imaging appearances and time-intensity curve of dynamic contrast-enhanced MR imaging.

Results

Ossifying fibromas occurred in the maxillary sinus in one patient, sphenoid sinus in 2, frontal sinus in 3, frontoethmoid sinuses in 3, and ethmoid sinus in 6 patients. Ossifying fibromas showed an elliptic-shape and aneurysmal bone cysts revealed a multicystic appearance, with well-demarcated margins. On unenhanced CT, ossifying fibromas appeared isodense to gray matter with scattered calcifications in nine, ground-glass appearance in 6 patients and aneurysmal bone cysts showed mixed density. Ossifying fibromas appeared isointense to gray matter in 12 and slightly hypointense in three patients on T1-weighted images, and isointense in 4 and hypointense in eleven patients on T2-weighted images, with moderate or marked enhancement after administration of contrast material. The time-intensity curves of eight ossifying fibromas exhibited a rapidly enhancing and rapid washout pattern. The intracystic components of aneurysmal bone cysts showed heterogeneous signal intensity on MR images, with fluid–fluid levels identified clearly by T2-weighted images, without enhancement. The periphery and septa of aneurysmal bone cysts appeared isointense on MR images, with marked enhancement.

Conclusions

Fluid–fluid levels within an elliptic-shape mass with scattered calcifications or ground-glass appearance is highly suggestive of this complicated entity in the paranasal sinus.     

Acute spontaneous spinal epidural hematomas.

BACKGROUND AND PURPOSE: Although previous reports have characterized MR imaging features of spinal epidural hematomas (EDH), few cases have been reported during the acute or hyperacute phase within the first 48 hours. Our goal in this investigation was to correlate the MR imaging features of acute (< or =48 hours) spontaneous EDH with clinical management and outcome. METHODS: Eight patients with acute spontaneous EDH (five men and three women; age range, 31-81 years) underwent MR imaging at 1.5 T (T1-weighted, n = 8; T1-weighted after the administration of 0.1 mmol/kg contrast material, n = 6; T2-weighted, n = 8; and T2-weighted, n = 4). The interval from symptom onset to hospital admission ranged from immediate to 5 days. Two neuroradiologists reviewed the MR images for signal characteristics, contrast enhancement, and cord compression. Treatment and clinical outcome were correlated with the imaging findings. RESULTS: The EDH were located in the cervical (n = 3), cervicothoracic (n = 2), thoracolumbar (n = 2), and lumbar (n = 1) regions. On T1-weighted images, the signal intensity of the EDH was isointense to spinal cord in five cases, hyperintense in two cases, and hypointense in one case and did not correlate with time to imaging. Isointensity on T1-weighted images persisted for 5 days in one case. On T2-weighted images, all EDHs were hyperintense with focal, heterogeneous hypointensity. Cord compression was severe in six patients, moderate in one patient, and minimal in one patient. Four cases were treated conservatively with complete resolution or improvement of symptoms within 1 to 3 weeks. CONCLUSION: MR imaging findings were useful in establishing the diagnosis of EDH but did not influence management or predict outcome in this series. Heterogeneous hyperintensity to cord with focal hypointensity on T2-weighted images should suggest the diagnosis of acute spinal EDH. Severity of neurologic impairment had the greatest impact on management and outcome. Nonoperative treatment may be successful in cases with minimal neurologic deficits, despite cord compression revealed by MR imaging.     

Spinal epidural extraskeletal Ewing sarcoma: MR findings in two cases

SUMMARY: We report the CT myelography and MR findings of two cases of extraskeletal Ewing sarcoma involving the spinal epidural and paravertebral spaces in a middle-aged man (case 1) and a young woman (case 2). In both cases CT myelography showed epidural and paravertebral masses on one side, with widening of the ipsilateral neural foramina at the C5-C6 level in case 1 and at the C7-T1 level in case 2. On MR images, the masses were isointense to muscle on T1-weighted images, hyperintense on T2-weighted images, and showed moderate enhancement on contrast-enhanced T1-weighted images. In one case, all pulse sequences showed linear signal voids, representing the vertebral artery encasement within the mass. The intradural component connected with the main mass was detected in the other case.     

脊髓血管母细胞瘤的MR影像研究

目的　分析脊髓血管母细胞瘤的MR影像表现。方法　经手术病理证实的脊髓血管母细胞瘤 29例,男 20例,女 9例,所有病例均行MR检查,回顾分析其MR影像表现。结果　12例单发(41. 4% ), 17例多发(58. 6% ),合并颅内血管母细胞瘤 7例。MR平扫时肿瘤表现为等T1 等T2 信号 36个,等和低混杂T1 信号、等和高混杂T2 信号 16个,长T1 长T2 信号 1个。小的肿瘤倾向于等T1 等T2 信号。增强扫描后肿瘤显著强化,边界清楚。17例患者中的 21个肿瘤在T2 加权像上可见血管流空信号。27例患者中的 40个肿瘤合并有较长的脊髓空洞或囊肿。结论　脊髓血管母细胞瘤常多发或合并颅内血管母细胞瘤,肿瘤结节边界清楚,强化显著以及肿瘤相关的血管流空信号对该肿瘤的诊断最有意义。     

Epidural abscess of the cervical spine: MR findings in five cases.

Cervical epidural abscess is an uncommon infectious process of the spinal epidural space. Although this disorder is often unsuspected clinically, the patient's signs and symptoms may suggest other diagnoses that frequently lead to an MR examination. We retrospectively reviewed the MR examinations of five patients with surgically proved cervical epidural abscess in order to assist in the diagnosis of this clinically elusive disorder. Each epidural abscess was evaluated for MR signal intensity, location, extent, delineation, and enhancement pattern. We assessed the spinal cord for compression and signal intensity and analyzed the vertebrae, intervertebral disks, and paraspinal soft tissue. Compared with the spinal cord, the abscess was isointense or hypointense on T1-weighted spin-echo images and hyperintense on T2-weighted images. The abscess was hyperintense or isointense relative to the cord on T2* gradient-echo images. Enhancement of the abscess occurred in the two patients given an IV injection of gadopentetate dimeglumine. The epidural abscess was located anteriorly in three patients, posteriorly in one, and was circumferential in one. The abscess extended from two to nine vertebral bodies in length. In each case, the abscess caused some degree of spinal cord compression, and one patient had bright signal intensity within the cord on T2-weighted images. Three patients had MR changes of accompanying osteomyelitis and paravertebral abscess. MR imaging is useful in diagnosing cervical epidural abscess and in evaluating associated abnormality of the spinal cord, vertebral bodies, intervertebral disks, and paraspinal soft tissue.     

Radiological findings of spinal schwannomas and meningiomas: focus on discrimination of two disease entities

This study evaluates the effectiveness of CT and MR imaging in differentiating intradural extramedullary spinal schwannomas and meningiomas in a large group of patients. In addition, the study correlates tumour location, morphologic characteristics and enhancement pattern. From January 2000 to June 2007, we retrospectively reviewed 128 consecutive patients (51 male, 77 female; mean age at admission 53.8 years; range 17–83 years) with spinal intradural extramedullary tumours (92 schwannomas, 36 meningiomas) at our institution. Fifty-one of ninety-two schwannomas (55.4%) showed fluid signal intensity on T2-weighted MR images. Twenty-two of thirty-six meningiomas (61.1%) showed hyperintense signal intensity and thirteen of thirty-six meningiomas (36.1%) showed isointense signal on T2-weighted MR images. Fifty-four schwannomas (58.7%) showed rim enhancement and thirty-three meningiomas (91.7%) showed diffuse enhancement on contrast-enhanced T1-weighted MR imaging. Twenty-one meningiomas (58.3%) showed dural tail sign in contrast-enhanced T1-weighted MR imaging. Twenty-one meningiomas (58.3%) showed calcification on CT images. MR and CT imaging results are therefore useful for the differentiation of schwannomas from meningiomas of the spine.     

Visceral metastases from melanoma: findings on MR imaging.

Typical ocular and CNS melanomas are hyperintense on T1-weighted MR images and hypointense on T2-weighted MR images. We performed MR imaging in 48 patients with melanoma metastatic to visceral organs. Images were reviewed retrospectively in order to determine whether there were predominant MR features specific for visceral melanoma and to see if visceral metastases have MR characteristics similar to metastases in the CNS. Eleven patients also were examined after injection of gadopentetate dimeglumine to evaluate the enhancement characteristics of these tumors. Two hundred sixty-one lesions were found. Lesions were classified according to their signal intensities relative to uninvolved liver on T1-weighted, T2-weighted, and short TI inversion recovery (STIR) pulse sequences. Most commonly, lesions were either hypointense or isointense on T1-weighted sequences and hyperintense on T2-weighted and STIR sequences (185 lesions). Less frequently, lesions were hyperintense on T1-weighted sequences and hypointense or isointense on T2-weighted and STIR sequences (59 lesions). A mixed pattern was seen on T1- and T2-weighted sequences in 17 lesions. The patterns did not correlate with lesion size. Of the three sequences studied by subjective comparison, the STIR sequence in our series had the highest sensitivity for lesion detection and yielded the highest lesion conspicuity. Injection of gadopentetate dimeglumine in 11 patients did not increase either the number or the conspicuity of lesions seen. Our results show that visceral metastases from melanoma have a wide variety of appearances on MR images. The STIR sequence appears to be optimal, and the metastases do not enhance with gadopentetate dimeglumine.     

Irradiated carcinoma of the tongue: correlation of MR imaging findings with pathology

OBJECTIVE: MR imaging was prospectively correlated with pathologic findings to study whether MR imaging can differentiate viable from nonviable tumor tissue in the irradiated carcinoma of the tongue. SUBJECTS AND METHODS: MR examinations were performed after radiation therapy in 21 patients with carcinoma of the tongue. All patients underwent either a total glossectomy or hemiglossectomy after radiation therapy. Specimens were examined microscopically. Radiation changes were histologically graded into four groups (I, minimal cellular changes; II, presence of cellular changes and partial destruction of the tumor; III, only nonviable tumor cells; IV, no tumor cells). MR examinations included T2-weighted imaging, unenhanced T1-weighted imaging, dynamic contrast-enhanced imaging, and contrast-enhanced T1-weighted imaging. RESULTS: On unenhanced T1-weighted images, the lesion was hypointense, except for two patients with histologic grade III. On T2-weighted images, the lesion appeared hyperintense in 12 of 14 patients with viable tumor cells (grades I and II); however, the lesion was hypointense in four, and isointense in two of seven patients with nonviable tumor cells (grades III or IV). Contrast-enhanced T1-weighted images showed that the degree of contrast enhancement of the lesion was equal to or lower than that of a normal salivary gland in 18 of 21 patients. For the time of maximal enhancement of the lesion on dynamic imaging, there was no substantial difference between viable (grades I and II) and nonviable (grades III and IV) tumor tissue. CONCLUSION: The present study shows that T2-weighted imaging is feasible for differentiating viable from nonviable tumor tissue in irradiated carcinoma of the tongue.