Showed Rim Enhancement Research Articles

Melanoptysis: findings on CT and MRI

The purpose of this study was to demonstrate the CT and MRI features of liquefied progressive massive fibrosis (PMF) in coal worker's pneumoconiosis (CWP). A retrospective analysis was made of the CT and MRI features in five patients suffering from severe CWP with the initial clinical finding of melanoptysis ("black phtisis"). CT showed either an air-fluid level or a fluid-precipitate level with high density in the dependent layer. On pre-contrast T(1) weighted images, liquefied PMF showed a fluid level with isointensity relative to soft tissue in the upper layer and a signal loss in the dependent layer of the lesion. The wall of the PMF showed rim enhancement after administration of iv gadolinium. On T(2) weighted images there was a high signal intensity in the upper layer of the lesion. In conclusion, liquefied PMF results in characteristic features on CT and MRI owing to precipitation of silica in the mucous fluid.

Imaging of Primary Non-Hodgkin's Lymphoma of the Liver

AIM: To describe the radiological findings in primary liver lymphoma, which is a rare entity, presenting usually as a localized liver mass. MATERIALS AND METHODS: We reviewed retrospectively the imaging findings at presentation, of patients in whom a diagnosis of primary liver lymphoma was finally made histologically. The study period covered a 10-year period between January 1990 and December 1999. There were seven patients, all men, with a mean age of 49.6 years. Each patient presented with hepatobiliary disease without peripheral adenopathy. Imaging prior to diagnosis included ultrasonography (seven patients), computed tomography (seven patients) and magnetic resonance imaging (MRI) (two patients). Appearances during and after aggressive chemotherapy were reviewed. RESULTS: Imaging appearances were of either single or multiple liver lesions simulating liver metastases. On ultrasound all foci of primary hepatic lymphoma (PHL) were hypoechoic relative to normal liver. Computed tomography (CT) showed hypoattenuating lesions in all cases, and two cases showed rim enhancement following contrast administration. The MRI appearances were variable, and no pathognomonic feature of PHL was identified, so that histology was required in all patients to establish the diagnosis. CONCLUSIONS: This paper demonstrates the spectrum of findings encountered on various imaging modalities in PHL. We conclude that although PHL is a rare condition, it should always be considered in the differential diagnosis of liver metastases when no primary tumour is apparent. Maher, M. M.et al. (2001). Clinical Radiology56, 295–301.

Posterior epidural migration of an extruded free fragment from a lumbar disc herniation

The majority of symptomatic lumbar disc herniations are located in a posterolateral position with resultant nerve root compression. Although caudal, rostral and lateral migrations of disc fragments are common, posterior epidural migration of an extruded free fragment from a lumbar disc herniation is a rare occurrence and sometimes may cause a dural sac compression with cauda equina syndrome. This retrospective case report describes a 63-year-old man with intractable lower back pain and cauda equina syndrome. Emergency magnetic resonance imaging (MRI) revealed a posterior epidural soft tissue compressing the dural sac. The lesion was hypointense on T1-weighted images, hyperintense on T2-weighted images and showed rim enhancement after intravenous injection of gadolinium. A laminectomy at L3 was performed and the extruded disc fragment was removed with dural sac decompression. Postoperatively the patient's radicular symptoms completely resolved. At the 2-year follow-up visit, the patient had recovered full motor, sensory and urinary functions. MRI is the modality of choice in the evaluation of an extruded free disc fragment and a cauda equina compression. In such cases a wide decompressive laminectomy is recommended.

Computed tomography and magnetic resonance tomography in tuberculous spondylitis. A review of the literature and the authors' own observations

The findings of tuberculous spondylitis in MRT have been described extensively. Nevertheless the diagnostic value of both methods in the diagnosis of this severe manifestation of the tuberculous disease was not yet defined definitely. We performed a review of the recent literature and a retrospective analysis of the findings in ten patients with proven tuberculous spondylitis. Here we evaluated 10 CT and 6 MRT. Major findings in computed tomography (n = 10) were osseous sequestration (8/10), subperiosteal bone apposition (6/10), abscess of the surrounding tissue. (8/10) and calcification of the masses (3/10). In all cases which were examined by MRT (n = 6) marrow edema was seen. Affection of the soft tissue was described by means of MRT in 5/6 patients. All patients showed rim enhancement. MRT shows signs of infection (bone marrow edema) which is an early but rather unspecific finding. The commonness of osseous lesions in advanced tuberculous spondylitis suggests a benefit of computed tomography in the later stages. Both methods are complementary in the differential diagnosis of tuberculous and non-specific spondylitis.

Ｂａｒｒ´ｅ‐Ｌｉ´ｅｏｕ徴候を伴った頚椎カリエスの１例

Tuberculosis of the cervical spine is uncommon to arise in the whole apine. We report a case of tuberculous cervical spondylitis with Barre-Lieou syndrome.The case was a 61 year old female, who complained of mild muscle weakness and strong dizziness at motion, headache, nausea, so called Barre-Lieou syndrome. MRI showed rim enhancement of the retropharyngeal soft tissue and peridural abscess. We therefore performed the operation of curretage and anterior spinal body fusion by use of autogenous fibula bone, adding the chemotherapy of INH, RFP and SM. She gradually recovered from Barre-Lieou syndrome.The origin of Barre-Lieou syndrome in this case was unsidered the source of the irritation of the vertebral nerve by tuberculous abscess.

Metastases to the pancreas.

Disparity in prognosis and management between primary and secondary pancreatic tumours makes recognition of metastases to the pancreas on CT and MRI an important goal. Three different patterns of secondary pancreatic tumours may be seen: localized, multifocal, or diffuse enlargement. CT findings include hypodense lesions, which show rim enhancement following intravenous contrast medium. On MR examination, the lesions are usually hypointense on T1 weighted and hyperintense on T2 weighted images.

Double phase CT arteriography of the whole liver in the evaluation of hepatic tumors.

Our goal was to evaluate the contribution of double phase CT arteriography (CTA) of the whole liver to differentiate hepatic tumors from false-positive areas on CT during arterial portography (CTAP). In 38 candidates for surgical resection of hepatic tumors, both CTAP and double phase CTA were performed. A total of 68 perfusion defects were identified at CTAP. Of 68 perfusion defects, 47 were found to represent hepatic tumors [hepatocellular carcinoma (HCC), n = 31; hepatic metastasis, n = 13; cholangiocarcinoma n = 2; focal nodular hyperplasia, n = 1]. The other 21 perfusion defects were defined as perfusion abnormalities in which focal hepatic masses had not been identified at surgery or pathologic analysis. The phase one CTA scanning started 12 s after the beginning of the injection of contrast material, and the phase two CTA scanning started 20 s after the end of the phase one CTA, with 60 ml of contrast agent (150 mg I/ml) injected at a rate of 2 ml/s. On phase one CTA, only 1 lesion in 31 HCCs showed rim enhancement and 26 HCCs (84%) had rim enhancement on phase two CTA. Twelve lesions (80%) of the hepatic metastases and cholangiocarcinomas had rim enhancement on phase one CTA and 11 lesions (73%) showed rim enhancement on phase two CTA. Twenty-one perfusion abnormalities on CTAP did not show rim enhancement on either phase one or phase two CTA. Double phase CT arteriography of the whole liver was useful to differentiate hepatic tumors from perfusion abnormalities on CTAP.

Typical and atypical MR imaging features of intracranial epidermoid tumors.

We categorized the MR imaging characteristics of intracranial epidermoid tumors. MR images from 23 cases of intracranial epidermoid tumors were reviewed retrospectively. Signal intensities of tumor relative to surrounding structures were noted, as were the internal architecture of the tumors and the presence and degree of hydrocephalus. Seventeen (74%) of 23 cases of intracranial epidermoid tumors were revealed as slightly hyperintense relative to CSF on T1-weighted MR images. Nineteen (95%) of 20 cases were hyperintense relative to CSF on proton density-weighted MR images. Fifteen (65%) of 23 cases were isointense to CSF on T2-weighted MR images, whereas the remaining eight cases (35%) were hyperintense to CSF on T2-weighted MR images. One (4%) of 23 cases showed signal intensity that was isointense to CSF on all pulse sequences. Fifteen (65%) of 23 cases showed heterogeneous signal characteristics on either T1-weighted or proton density-weighted MR images, or both. Eight (35%) of 23 cases showed a rim of hyperintensity on proton density-weighted MR images. Five (33%) of the 15 cases that received gadolinium showed rim enhancement. Five (22%) of 23 cases were multilocular, with different regions of tumors showing highly variable imaging characteristics. Two (9%) of 23 cases showed high signal intensity on T2-weighted MR images in the adjacent brain parenchyma. Two (9%) of 23 cases showed mild hydrocephalus. Six (43%) of 14 tumors that either originated in or secondarily involved the cerebellopontine angle also extended into the ipsilateral Meckel's cave. On T1-, proton density-, and T2-weighted MR images intracranial epidermoid tumors usually showed heterogeneous signal intensity that was hyperintense to CSF. On all spin-echo pulse sequences epidermoid tumors with signal characteristics isointense to CSF were unusual. Hydrocephalus, even in the setting of marked displacement and compression of the brainstem, was not usually seen on MR imaging. Meckel's cave was often involved secondarily with epidermoid tumors that involved the cerebellopontine angle.

Hepatic abscesses: MR imaging findings.

To determine magnetic resonance (MR) imaging features that characterize hepatic abscesses. Clinical records and MR studies of 18 patients with proved hepatic abscesses were evaluated. The abscesses were pyogenic in 15 patients, fungal in two patients, and amebic in one patient. A total of 122 lesions were identified. Most were round (n = 114) with sharp borders (n = 99), hypointense on T1-weighted images (n = 73), and very hyperintense on T2-weighted images (n = 88). After injection of gadopentetate dimeglumine in 43 lesions, all 43 enhanced with sharp margins and 37 showed rim enhancement. All abscesses followed up diminished in size (50 of 50), and perilesional edema resolved before the central cavity did. MR imaging findings seen in hepatic abscesses include high signal intensity on T2-weighted images (72%) and perilesional edema (43 of 122 [35%]). Rim enhancement (86%) and increased conspicuity (35 of 43 [81%]) were found after injection of gadopentetate dimeglumine.

Case report: Multiple intracranial hydatid cysts with post-operative dissemination

A case of primary multiple intracranial hydatid cysts is reported. The cysts were both supratentorial and infratentorial. One showed rim enhancement and perifocal oedema. Post-operatively, the number and size of cysts increased, possibly because of intraoperative rupture.