Central Hyperintensity Research Articles

Spinal dural arteriovenous fistula: clinical and radiological findings in 54 patients

Presentation of the clinical and radiological findings in spinal dural arteriovenous fistulas (SDAVF) based on the experience in 54 patients. Evaluation of patients' records and myelography (n = 23), MRI (n = 54) as well as conventional angiography (n = 54) with respect to history, symptoms, clinical and radiological results. Clinically, a long history (mean 20 months) with progressive ascending paresis (100 %), sensory deficits (93 %) and loss of control over bladder and bowel function (89 %) in male patients (78 %) of advanced age (mean 60 years) indicates the disease. Typical signs in MRI are central cord hyperintensity (100 %) with slight medullary distension (74 %), contrast enhancement (79 %) and distended perimedullary veins (89 %), the latter being disclosed by myelography in 78 % of cases. For diagnosis spinal angiography is necessary which most often shows a thoracic location of the fistula (69 %), more than one feeding artery (67 %) and caudal as well as rostral venous drainage (63 %). MRI is superior to myelography to detect diagnostic signs of SDAVF in patients with typical clinical presentation. For definitive diagnosis spinal angiography is still indispensable.

Clinical findings in nondemented mutation carriers predisposed to Alzheimer's disease: a model of mild cognitive impairment.

Individuals carrying a mutation associated with Alzheimer's disease (AD) may serve as a model of mild cognitive impairment (MCI). Nondemented individuals from these families can be subdivided into asymptomatic and symptomatic groups. Four families were studied. Two families are associated with APP mutations (KN670/671ML, E693G) and two with PS1 mutation (M146V, H163Y). Clinical symptoms, level of global cognitive functioning as evaluated by Mini-Mental State Examination, neuropsychological test results, neuroradiological examinations (magnetic resonance imaging (MRI) and single-photon emission tomography (SPECT)), as well as cerebrospinal fluid (CSF) measurements of tau and beta-amyloid are reported. Nondemented mutation carriers did not report any symptoms indicating cognitive decline. In addition, no clinical signs of dementia or marked cognitive impairment in neuropsychological tests were found. A reduction of temporal blood flow with SPECT was indicated in 5/13 nondemented mutation carriers. Two of these 13 individuals had moderate hyperintensities in deep white matter as observed on MRI. CSF measurements of A beta 42/43 were inconclusive because of large biological variation. A nonsignificant elevation of tau was detected in mutation carriers. In conclusion, clinical examinations of relatively young individuals carrying an AD mutation did not reveal any marked abnormalities before the clinical onset of dementia.

MR imaging of the normal appendix in children.

Our objective was to assess the ability of MR imaging in the detection of the normal appendix, and to describe the MR appearance of the normal appendix. There were 15 healthy volunteers (11 girls, 4 boys; mean age 12.3 years) who underwent MR imaging on a 1.0-T unit. The imaging protocol included axial and coronal T2-weighted ultra turbo spin-echo (UTSE)-weighted images, axial T1-weighted turbo spin-echo (TSE) and coronal short tau inversion recovery (STIR)/TSE sequences. Confidence regarding the detection was scored from 1 (high confidence) to 3 (low confidence). Thickness was measured and MR appearance described. Clinical control after 2 weeks revealed no signs or symptoms of acute appendicitis. The normal appendix was seen in 86% on T2/UTSE-weighted images and in 73% on T1/TSE-weighted images and in none on STIR/TSE images. On axial T2/UTSE-weighted images, normal appendix had a hyperintense center and a hypointense wall, and was mostly hypointense on T1/TSE-weighted images, with a mean thickness of 4.5 mm. Magnetic resonance imaging seems to be an accurate method for the assessment of the normal appendix in children; thus, MR imaging might be an alternative to CT if US examinations are inconclusive.

Aspiration biopsy of nodular sarcoidosis of the muscle No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were received in support of this study.

The nodular form of muscular sarcoidosis is rare and the condition is often confused with a soft tissue neoplasm. We present a case of nodular muscular sarcoidosis of the right calf in a 52-yr-old woman which was diagnosed by thin-needle aspiration biopsy (TNAB). In this patient, a calf mass was the initial manifestation of sarcoidosis. Contrast-enhanced computed tomographic scans of the calf showed a mass with peripheral ring-like enhancement. T2-weighted magnetic resonance images demonstrated a mass with central hypointensity and marked peripheral hyperintensity. TNAB revealed noncaseating epithelioid cell granulomas in association with multinucleated giant cells. Combined with the radiologic findings, TNAB is considered a useful modality for the diagnosis of nodular muscular sarcoidosis. Diagn. Cytopathol. 2002;26:109–112; DOI 10.1002/dc.10055 © 2002 Wiley-Liss, Inc.

Aspiration biopsy of nodular sarcoidosis of the muscle

The nodular form of muscular sarcoidosis is rare and the condition is often confused with a soft tissue neoplasm. We present a case of nodular muscular sarcoidosis of the right calf in a 52-yr-old woman which was diagnosed by thin-needle aspiration biopsy (TNAB). In this patient, a calf mass was the initial manifestation of sarcoidosis. Contrast-enhanced computed tomographic scans of the calf showed a mass with peripheral ring-like enhancement. T2-weighted magnetic resonance images demonstrated a mass with central hypointensity and marked peripheral hyperintensity. TNAB revealed noncaseating epithelioid cell granulomas in association with multinucleated giant cells. Combined with the radiologic findings, TNAB is considered a useful modality for the diagnosis of nodular muscular sarcoidosis.

Intraocular metastases: differential diagnosis from uveal melanomas with high-resolution MRI using a surface coil.

Magnetic resonance imaging with dedicated surface coils plays a pivotal role in differential diagnosis and staging of intraocular tumors. The purpose of this study was to establish MRI criteria for the differential diagnosis of uveal melanomas and intraocular metastases. In a prospective study 44 eyes in 36 patients with intraocular metastases and 200 patients with uveal melanomas were investigated with MRI using a 1.5-T scanner and a 5-cm surface coil. Both quantitative and qualitative evaluation of the resulting images was performed. The MR signal intensities typically expected for metastases (slightly hyperintense on non-contrast T1-weighted images and hypointense on T2-weighted images compared to the vitreous body) were seen in only 23.1%. The typical melanoma signal of either moderate or strong hyperintensity on T1-weighted images and hypointensity on T2-weighted images was seen in 69.4% of the proven melanomas. Contrast enhancement was observed in both metastases and melanomas. Morphological differences between metastases and melanomas were detected in tumor size, shape, position, frequency of retinal detachment, and homogeneity of the tumor. Differentiation between intraocular metastases and uveal melanoma is limited by overlap of signal intensities. Some improvement is achieved with morphologic criteria.

The role of MRI in the intestinal complications in cystic fibrosis

Fibrosing colonopathy is a complication recently detected in children with cystic fibrosis (CF), and is thought to be associated with the use of high-strength pancreatic enzymes. The goal of this study was to evaluate the effectiveness of magnetic resonance (MR) in detecting possible pathologic gut findings in patients with CF under pancreatic enzyme treatment. Twenty-five patients with CF and pancreatic insufficiency, all under treatment with high-dose pancreatic enzymes, were studied by MR. MR was performed on a 1.5-T magnet by T1-weighted, 2D-FLASH fat-suppression, breath-hold sequences before and after intravenous administration of gadolinium, and by T2-weighted Turbo Spin-Echo (TSE) and Half-Fourier Acquisition Single-Shot Turbo Spin Echo (HASTE) fat-suppression, breath-hold sequences. A superparamagnetic negative oral contrast agent was given 1.5 h before the examination. MR showed a wall thickening of the terminal ileum and the ascending colon (>4–12 mm) in 22 patients; nine of them (wall thickness >4–6 mm) showed both a moderate hyperintensity of the bowel wall on T2-weighted sequences and an enhancement after intravenous gadolinium on T1-weighted sequences; 13 patients (wall thickness >6–12 mm) showed both a great wall enhancement after intravenous gadolinium and an increased signal intensity of the bowel wall on T2-weighted sequences. Fecal impaction without bowel wall involvement was detected in three patients. MR proved to be a useful, noninvasive, diagnostic tool for the evaluation of patients with CF and fibrosing colonopathy. The signal hyperintensity on T2-weighted sequences and the great wall enhancement after intravenous gadolinium administration indicating an acute edematous condition, provide the clinicians useful information for the therapeutic adjustment.

A true aneurysm of the femoral artery in acromegaly

We report on an acromegalic patient who developed a true aneurysm in the right femoral artery. Plain computed tomography (CT) showed a soft tissue mass with low density adjacent to the right femoral artery. T1-weighted magnetic resonance (MR) images exhibited the lesion with moderate hypointensity peripherally, and hypointensity centrally. T2-weighted images showed the lesion to have areas of hypointensity, moderate hyperintensity, and marked hyperintensity. Surgery revealed an ectasia of the common femoral artery and a true aneurysm from the lateral femoral circumflex artery.

Intramedullary tuberculomas: MR findings in seven patients

To describe the MR findings in intramedullary tuberculomas and to discuss the usefulness of MR in the management of this pathology. A retrospective study of 7 patients from 21 to 60 years of age with clinical and radiological evidence of intramedullary tuberculomas was undertaken. Both T1- and T2-weighted images (WI) were obtained along with postcontrast T1WI. Signal intensities (SIs) of the granulomas were compared with SIs of the normal spinal cord. Six patients showed focus of tuberculosis elsewhere in the body. Six out of 7 showed fusiform swelling of the cord. Ill-defined iso-intensity (in 4 patients) to hyperintensity (in 3 patients) was seen at the site of granuloma on T1WI. On T2WI, 2 patients revealed a hypointense area (with disc enhancement). An iso-hypointense rim was seen surrounding a hyperintense centre in 5 patients (with rim enhancement). Adjacent oedema was seen in all patients. In 2 patients meningeal enhancement was also seen. In 2 patients the histopathology following surgical biopsy confirmed the diagnosis. In the remaining 5 patients, another known focus of tuberculosis elsewhere in the body and a marked response to antitubercular treatment was considered confirmatory for tuberculomas. Hypo- or iso-intensity on T2WI within the spinal cord with surrounding hyperintense oedema is suggestive of intramedullary tuberculomas. Central hyperintensities are also detected at times due to a variable amount of caseous necrosis with liquefaction. On T1WI, fusiform swelling of the cord is seen along with iso- to hyperintense foci, surrounded by hypointense oedema of the cord. Such findings should prompt a contrast-enhanced study, which may show single or conglomerate disc- or ring-enhancing lesions. MR thus plays an important role not only in detection and diagnosis, but also in deciding the treatment options and in the follow-up of those patients.

Abdominal tuberculous lymphadenopathy: MR imaging findings

The purpose of this study was to evaluate the utility of magnetic resonance imaging (MRI) as a diagnostic tool in abdominal tuberculous lymphadenopathy. MRI studies of 11 patients with histologically proven abdominal tuberculous lymphadenopathy were reviewed with regard to anatomic distribution, size, shape, degree, and pattern of enhancement and relation of the lesions to adjacent structures. The most common site of involvement was the periportal area (n = 6), followed by the peripancreatic (n = 5), mesenteric (n = 1), and paraaortic (n = 1) areas. Eight patients were readily diagnosed as having tuberculous lymphadenopathy on abdominal computed tomography. Three patients had a heterogeneously enhancing masslike lesion adjacent to the pancreas and were initially diagnosed as having cystic tumor of the pancreas. On MRI, 11 lesions showed T1 iso- or hypointensity and central T2 hyperintensity. Two lesions showed T1 iso- or hypointensity and central T2 hypointensity. The lesions with different T2 signal intensities showed different patterns of enhancement on contrast-enhanced dynamic studies. The relations between the enlarged lymph nodes and adjacent bile ducts or vascular structures were well depicted on MRI. MRI was useful in differentiating enlarged lymph nodes abutting the pancreas initially diagnosed as cystic neoplasms on abdominal computed tomography.

Imaging of Melorheostosis: Emphasis on MR Imaging Findings

Purpose: To evaluate the usefulness of various radiographic imaging modalities in the diagnosis and characterization of melorheostosis. Materials and Methods: We retrospectively evaluated the plain film (n=8), computed tomographic (CT) imaging (n=5) and magnetic resonance (MR) imaging (n=5) findings of eight patients with melorheostosis diagnosed by bone biopsy (n=4) and characteristic radiographic findings (n=8). MR images were obtained with a 1.5-T scanner focused on the region of maximal radiographic abnormality. Pulse sequences include T1-weighted SE, T2-weighted fast SE (n=5) and postcontrast imaging (n=4). In order to define subtle enhancement of the lesions, subtraction MR images were obtained in one case. Imaging findings were analyzed with particular emphasis on the distribution of lesions along the sclerotome, differential radiographic findings between diaphyseal and metaepiphyseal lesions of the long bones, as seen on plain radiographs, and the density and signal characteristics of hyperostotic, lesions, as seen on CT and MR images. Results: Characteristic distribution along the sclerotome was identified in five of eight cases mainly along C6 and 7 (n=2) and L3, 4 and 5 (n=3) sclerotomes. In diaphyseal melorherostosis (8/8), a characteristic finding, i.e., a wax flowing down from the candle, was identified on plain radiographs. In all three patients with metaepiphyseal melorheostosis (3/8), multiple round or oval hyperostotic lesions were seen in the epiphysis and metaphysis of the long bones. On CT, the marrow cavity was partly obliterated by hyperostotic lesions in all five patients with endosteal hyperostosis. Among these, central ground glass opacity with a sclerotic rim was seen in three patients. Periosteal hyperostosis was seen in two of five cases, being visualized as irregular excrescences in the periosteal region and surrounding soft tissue. Individual hyperostosis was visualized as hypointense on T1-weighted images and as a hyperintense center with a surrounding hypointense rim on T2-weighted images (5/5). On postcontrast images, central enhancement was noted in all four cases. In one of these, in which the degree of central enhancement was subtle, subtraction images (postcontrast SE- precontrast SE) also revealed a central signal increment. Central enhancement corresponded to the hyperintense center seen on T2-weighted images (4/4) and the ground-glass opacity seen on CT (2/2). Conclusion: Radiographic imaging plays a crucial role in the diagnosis of melorheostosis. The future role of gadolinium-enhanced MR imaging in the characterization of the lesion may be important though further evaluation and pathologic correlation is required.

Imaging and pathologic features of myelolipoma.

Myelolipoma is a benign tumor consisting of mature fat interspersed with hematopoietic elements resembling bone marrow. Imaging findings in a large series of pathologically proved cases of myelolipoma were correlated with the pathologic and histologic features of the lesions. Myelolipoma manifests in four distinct clinicopathologic patterns: isolated adrenal myelolipoma, adrenal myelolipoma with hemorrhage, extraadrenal myelolipoma, and myelolipoma associated with other adrenal disease. Myelolipoma is difficult or impossible to detect at plain radiography unless the lesion is large and predominantly fatty. At ultrasound, myelolipoma often has heterogeneous echogenicity due to its typically nonuniform architecture. Computed tomography (CT) frequently demonstrates large amounts of fat with areas of interspersed higher-attenuation tissue. At magnetic resonance imaging, predominantly fatty areas usually have increased signal intensity on T1-weighted images and moderate hyperintensity complicated by the presence of marrowlike elements in the corresponding regions on T2-weighted images. The imaging appearance of myelolipoma is altered by the presence of hemorrhage. In such cases, CT is the most accurate method for evaluation. Knowledge of the imaging characteristics of myelolipoma usually allows presumptive diagnosis, although percutaneous needle biopsy may be needed to confirm the diagnosis in cases of extraadrenal myelolipoma. Surgical excision is unnecessary unless the diagnosis is unclear or the lesion is symptomatic. Asymptomatic, nonhemorrhagic myelolipomas do not require therapy.

Late MR follow-up of hypothalamic hamartomas.

The absence of changes over time in the diagnostic features of suspected hypothalamic hamartomas is of paramount importance. Since magnetic resonance (MR) imaging is very sensitive to modifications in the brain parenchyma, a late MR follow-up study was performed in five children. In all cases, the diagnosis of hypothalamic hamartoma has been suspected on the basis of the association of central precocious puberty and the presence of a mass in the inferior aspect of the hypothalamus, demonstrated on previous MR studies. Late MR evaluation (after a mean of 39 months) demonstrated stability of the lesions in shape, size, and signal intensity. In three cases the lesions demonstrated a rim of isointense signal with a hyperintense center on T2-weighted sequences. In two cases a Chiari I malformation was found in association with the hypothalamic malformation. In one case a pineal cyst was demonstrated. These unusual findings are discussed. Late MR follow-up showed the absence of changes in the lesions over time, allowing the diagnosis to be confirmed.

Cigarette Smoking and Silent Brain Infarction in Normal Adults.

We investigated the relationship between cigarette smoking and silent brain infarction in 365 neurologically normal male Japanese subjects (smokers: 119, nonsmokers: 246). Silent brain infarction was identified in 32 (26.9%) of 119 smokers and in 54 (22.8%) of 246 nonsmokers. Mild or moderate periventricular hyperintensity was presented in 27 smokers (22.7%) and 54 nonsmokers (22.8%). There was no significant difference in the regional cerebral blood flow or the average systolic, diastolic, and mean arterial blood pressures between groups. The HDL-cholesterol level was significantly lower in smokers than in nonsmokers (p < 0.01). Cigarette smoking was not related to the incidence of silent brain infarction or leuko-araiosis in healthy adults in Japan.

Dark ring sign: Finding in patients with fungal liver lesions and transfusional hemosiderosis undergoing treatment with antifungal antibiotics

To describe the MR appearance of necrotizing fungal granulomas occurring in the liver of leukemic patients with hepatosplenic fungal disease and transfusional hemosiderosis on antifungal antibiotics. Four patients with acute myelogenous leukemia (n = 2) or acute lymphocytic leukemia (n = 2) who developed hepatosplenic fungal disease, and were treated with antifungal medication, underwent MRI examination on a 1.5 T MR imager. MR images were prospectively evaluated and correlated with liver biopsy (three patients), and clinical picture (one patient). Multiple liver lesions measuring approximately 1 cm in diameter were identified in all patients. Lesions possessed a distinctive MR appearance: central mild hyperintensity with a peripheral ring of very low signal intensity on precontrast T1- and T2-weighted images. The central region of the lesions enhanced following gadolinium administration with the peripheral ring remaining low in signal intensity. Necrotizing fungal granulomas in the liver of patients with transfusional hemosiderosis on treatment with antifungal antibiotics have a distinctive appearance of moderate high signal intensity center on T1- and T2-weighted and postgadolinium MR images with a peripheral rim of low signal intensity. This appearance reflects the presence of iron-laden macrophages in the periphery of granulomas and may be expected in processes that initiate an immune response involving aggregation of macrophages in the liver of patients with transfusional iron overload.

Visualisation of subchondral erosion in rat monoarticular arthritis by magnetic resonance imaging

High-resolution magnetic resonance imaging (MRI) was used to investigate antigen-induced monoarticular arthritis (AIMA) in the rat. In sagittal, spin-echo images of the knee, characteristic parallel bands, in the order dark-light-dark, were consistently observed 5-8 days after arthritis induction; the bands ran concentric with, and just beneath, the femoral and tibial articular surfaces. Concurrent radiology, histology and MRI (chemical shift-selective imaging and contrast enhancement with magnetisation transfer and gadolinium) established that the phenomenon reflected subchondral erosion, not artefact. The outer hypointense band corresponded to calcified cartilage underlying the articular surface. The central hyperintense band reflected inflammatory matrix displacing normal haematopoietic tissue immediately subchondrally; here, trabecular bone had mostly disappeared, but adjacent articular cartilage, although under attack and lacking proteoglycan, appeared structurally normal. The inner hypointense band reflected deeper, truncated trabeculae within inflammatory matrix, layered with pallisading osteoblast-like cells. This study exemplifies the power of MRI for revealing localised joint pathology non-invasively, and shows that rat AIMA shares many pathological features with arthritis in human beings.

Cerebral magnetic resonance imaging of liver cirrhosis patients

Thirty-two patients with liver cirrhosis underwent cerebral magnetic resonance imaging (MRI) to evaluate clinical and subclinical portal-systemic encephalopathy (PSE). Symmetrically hyperintense globus pallidi were observed on T1-weighted images in all 11 patients with PSE and in 15 of the 21 patients with PSE. This abnormality was classified as grade I (bilateral globus pallidi with mild to moderate hyperintensity relative to white matter), and grade II (marked hyperintensity bilaterally in the globus pallidi with mildly increased signal intensities in the surrounding structures). Portal-systemic collateral vessels were demonstrated in 23 of 24 patients who underwent abdominal angiography. In 18 of the 19 patients with abnormal MRI, collateral vessels were supplied by the superior mesenteric vein with or without the splenic vein, including four patients with collaterals which were less than 10 mm in diameter. We concluded that hyperintense globus pallidi on T1-weighted images are significant manifestations of clinical PSE. When portal-systemic collaterals supplied by the superior mesenteric vein are observed, even if they are of small diameter, cerebral MRI should be performed to evaluate for subclinical PSE.

Response of hepatocellular carcinoma to percutaneous ethanol injection: CT and MR evaluation.

The aim of the present study was to perform a comparative assessment of the contribution of imaging examinations to the evaluation of the response of hepatocellular carcinoma (HCC) to percutaneous ethanol injection (PEI). Twenty-five small HCCs (< 5 cm in diameter) were treated by means of PEI. The outcome of treatment, established on the basis of percutaneous biopsy and a 10 to 26 month follow-up, was complete necrosis in 23 of 25 cases and tumor persistence in 2 of 25. While ultrasound proved to be unable to distinguish posttreatment fibrosis from persisting neoplastic tissue, contrast-enhanced CT correctly identified the two cases of treatment failure, which showed the presence of enhancing areas within the lesion. The remaining 23 cases displayed a hypodense appearance, with no contrast enhancement on CT. Magnetic resonance demonstrated ethanol-induced coagulative necrosis as marked hypointensity on T2-weighted images in 21 of 25 cases. In four cases areas of high signal intensity on T2-weighted images within the nodule were observed after PEI: In two cases they were associated with tumor persistence, and in the other two with the presence of liquefactive necrosis. Our results demonstrate that different necrotic phenomena following ethanol injection therapy of HCCs may result in variable MR appearance. Although the location of hyperintense areas may suggest a differential diagnosis (central hyperintensity being more likely due to necrosis), CT remains the more reliable technique in the assessment of the response of HCC to PEI.

MRI of spinal hematoma as a result of lumbar puncture

A 59-year-old woman was suspected of having meningitis. A lumbar puncture was performed for CSF analysis; however, a traumatic tap induced hemorrhage in the subarachnoid space and formed a hematoma from the L3 to the S1 level. This resulted in a paraparesis. Myelography showed a band-like filling defect and a subsequent computed tomography (CT) myelogram showed a soft tissue mass in the intradural space. T1 weighted magnetic resonance imaging revealed a lesion with moderate hyperintensity within the dural sac, hinting that the lesion was a hematoma. Laminectomy was performed, and the hematoma was entirely removed.

Reduced brain N-acetylaspartate suggests neuronal loss in cognitively impaired human immunodeficiency virus-seropositive individuals: in vivo 1H magnetic resonance spectroscopic imaging.

We used magnetic resonance imaging (MRI) and water-suppressed proton magnetic resonance spectroscopic imaging to study the effects of human immunodeficiency virus (HIV) infection on the brains of 10 individuals with cognitive impairment due to HIV and seven normal controls. 1H spectra from nine 2.5-ml volumes in the centrum semiovale and the mesial cortex showed significantly reduced N-acetylaspartate (NAA) relative to choline and creatine in the cognitively impaired HIV-infected subjects. This reduction was due to a nonlocalized decrease of NAA in these patients, only two of whom had moderate atrophy and white matter signal hyperintensities on MRI. Since NAA is a putative neuronal marker, the findings suggest neuronal damage in early stages of HIV infection that is not evident on standard MRI and are consistent with the neuropathologically known neuronal loss.