High signal in the adenohypophysis on T1-weighted images presumably due to manganese deposits in patients on long-term parenteral nutrition

Hypermanganesaemia is reported in patients on long-term parenteral nutrition. Deposition of manganese, giving high signal on T1-weighted images, may involve the basal ganglia. MRI in nine patients (mean age 51 years, range 31–75 years) on long-term parenteral nutrition (mean duration 30 months, range 6–126 months), demonstrated high signal in the anterior pituitary gland on T1-weighted sagittal and coronal images. The gland appeared normal on T2-weighted images. Signal intensity in the basal ganglia on T1-weighted images was increased in all patients. Endocrine assessment showed no significant abnormality. Neurological examination showed a mild parkinsonian movement disorder in one patient. Hypermanganaesemia was present in all nine (1.3–2.8 μmol/l, mean 1.87 μmol/l). The high signal in the anterior pituitary gland was probably related to deposition of paramagnetic substances, especially manganese. Received: 20 January 1998 Accepted: 10 April 1998     

Intra-articular elastofibroma of the shoulder joint

A 19-year-old man presented with an elastofibroma in his left shoulder joint. The patient had had limitation of motion in his left arm for 3 years, especially when rotating internally. Radiography of his left shoulder showed bone erosion in the neck of the humerus. On MR imaging, a soft tissue mass was noted in the shoulder joint eroding bone. The mass showed similar signal intensity to that of surrounding muscles on T1- and T2-weighted images. At surgery, a soft, encapsulated mass was found attached to the subscapularis muscle. It was pathologically confirmed as an elastofibroma. This unusual manifestation of an elastofibroma is discussed.     

Intramuscular ganglia arising from the superior tibiofibular joint: CT and MR evaluation

Objective To evaluate the role of magnetic resonance imaging (MRI) and computed tomography (CT) in the diagnosis of intramuscular ganglia (IMG) that arise from the superior tibiofibular joint (STFJ).Material and Methods Our series consisted of three men and three women. Four patients were studied by MRI, one by CT only, and two by both modalities. Contrast was used in one of the two patients studied by CT. MRI was obtained in at least two orthogonal planes to demonstrate the relation of the ganglia to STFJ.Results The MR and CT appearance of these ganglia was basically that of a well-defined soft tissue mass with low attenuation on CT images consistent with the presence of fluid. On MR studies, they had an isointense signal on T1-weighted images and a homogenous high-intensity signal on T2-weighted images. MRI demonstrated the attachment of these ganglia to the STFJ.Conclusion CT and MRI were effective, noninvasive modalities in the evaluation of IMG. The imaging features on both modalities were consistent with the presence of fluid-containing lesions that had close proximity and were attached to the STFJ. The combination of location and the fluid consistency of these lesions facilitated the diagnosis.     

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.     

The various MRI patterns of pituitary apoplexy

The aim of this study was to describe the various MRI features, in correlation to surgical and pathological findings, in patients who presented with pituitary apoplexy (PA). Eleven patients presenting with PA, were evaluated with various MR protocols including spin-echo (SE) T1-weighted sequences in 9 of 11 patients, post gadolinium SE T1-weighted sequences in only 8 of 11 patients, and with T2-weighted SE sequences in 2 of 11 patients. All patients had transsphenoidal pituitary surgery after MR studies. The severity of presenting symptoms ranged from headaches to coma. Ten patients had pituitary macroadenoma; one had a non-hemorrhagic metastatic lesion into a non-adenomatous pituitary gland. Of the 11 patients, one was studied at the acute stage of PA (1 day after onset), 9 at the subacute period (3–15 days after onset), and one at the late stage (5 months after onset). Images compatible with intratumoral hemorrhage were found in all macroadenomas, whereas the metastatic pituitary lesion did not show evidence of bleeding. All gadolinium-enhanced studies showed partial tumoral enhancement. The SE T2-weighted studies demonstrated areas of low and high signal intensities in keeping with the presence of blood degradation contents. Pituitary apoplexy present with different MR features, including hemorrhagic and non-hemorrhagic characteristics on T1-weighted images. Gadolinium-enhanced images do not provide complementary diagnostic information when the presence of blood is assessed on plain images. Received: 20 May 1998; Revision received: 11 September 1998; Accepted: 14 September 1998     

Germinoma originating in the basal ganglia and thalamus: MR and CT evaluation.

PURPOSETo describe MR and CT features of germinoma originating in the basal ganglia and thalamus and to discuss the roles of each modality for its diagnosis.METHODSMR and CT studies of six cases of germinomas, five of which were histologically proved, were retrospectively reviewed. T1-weighted, T2-weighted, and contrast-enhanced T1-weighted conventional spin-echo images, and unenhanced and contrast-enhanced CT images were evaluated.RESULTSTypically, the tumor consisted of an irregular solid area with contrast enhancement and various-size cysts. Cystic components were found in five cases and calcification in four. Intratumoral hemorrhage was noted in one. Ipsilateral cerebral hemiatrophy and brain stem hemiatrophy were noted in three cases each. MR was superior to CT in evaluating precise tumor extension, cystic components, and intratumoral hemorrhage, although in one case, extension of the tumor was better defined on CT in its early stage. Calcification was difficult to identify by MR alone. The solid components of the tumors generally showed slightly high density on CT, which seemed to be characteristic compared with nonspecific intensity pattern on MR.CONCLUSIONThe combination of CT and MR findings allows early detection and appropriate diagnosis of the mass in the basal ganglia and/or thalamus.     

Atypical MRI presentation of a small splenic hamartoma

Hamartomas of the spleen usually appear isointense on T1-weighted MR images and hyperintense on T2-weighted images. We describe a histologically proven case which presented as a small (2.5 cm) focal mass isointense to splenic parenchyma on T1-weighted images and hypointense on both turbo-spin-echo T2 and short T1 inversion recovery images. Dynamic MRI revealed a delayed enhancement during the arterial phase becoming isointense and prolonged on subsequent images. This prolonged enhancement has previously been described as a characteristic pattern in these tumours. The lack of oedema and necrosis and the presence of fibrous tissue in the hamartoma at histopathology likely account for the low signal intensity on all sequences. Received: 9 February 1998; Revision received: 13 July 1998; Accepted: 17 July 1998     

Granular cell tumor of the subcutis: CT and MRI findings

Three cases of granular cell tumor (GCT) of the subcutis are presented. Computed tomography showed a mass isodense with muscle with an ill-defined margin. Magnetic resonance imaging showed a mass with inhomogeneous low signal intensity on both T1- and T2-weighted images. Another characteristic feature of subcutaneous GCT is its attachment in part to muscle. Histological examination confirmed the diagnosis in all cases. Received: 20 July 1998; Revision requested: 12 October 1998; Revision received: 30 October 1998; Accepted: 16 November 1998     

Rheumatoid arthritis of the knee: value of gadopentetate dimeglumine-enhanced MR imaging

In an attempt to differentiate among joint effusion, synovitis, pannus, and subchondral sclerosis in patients with clinically proved chronic rheumatoid arthritis, we used gadopentetate dimeglumine-enhanced MR imaging to examine 23 patients with acute knee symptoms. All patients had had rheumatoid arthritis for more than 6 months and satisfied four or more of the criteria of the American Rheumatism Association for rheumatoid arthritis. MR imaging was performed on a 1.5-T machine by using unenhanced T1-weighted spin-echo imaging, unenhanced T2*-weighted gradient-echo imaging, and unenhanced and enhanced T1-weighted gradient-echo imaging. Signal intensities of the synovium and bone marrow were measured with the region-of-interest technique on unenhanced and enhanced T1-weighted gradient-echo scans. Conventional radiographs were available for each patient. Joint effusion, synovitis, intraarticular pannus, subchondral sclerosis, and subchondral pannus had the same signal intensities on unenhanced T1-weighted spin-echo, unenhanced T1-weighted gradient-echo, and unenhanced T2*-weighted gradient-echo MR images, and could not be differentiated from one another. On enhanced T1-weighted gradient-echo sequences, pannus and synovitis showed marked enhancement in 15 patients, whereas joint effusion and sclerosis did not. Synovitis was diagnosed if the synovial membrane showed high enhancement; pannus was diagnosed if enhancing masses were seen within the joint space or in the subchondral area. In eight of the 23 joints, there was no enhancement of the synovium or intraarticular or subchondral tissue. We conclude that gadopentetate dimeglumine-enhanced MR imaging allows differentiation between synovitis and joint effusion and between subchondral pannus and subchondral sclerosis. Enhancement of the synovium and pannus indicates acute inflammation of the joint.     

MR imaging and proton MR spectroscopy in A-to-G substitution at nucleotide position 3243 of leucine transfer RNA.

MR imaging of the brain in a 38-year-old woman with maternally inherited diabetes and deafness (MIDD) showed extensive subcortical and basal ganglia high signal intensity on T2-weighted studies though she was neurologically asymptomatic. High-signal-intensity changes were also seen in the basal ganglia on T1-weighted studies. Proton MR spectroscopy showed increased lactate, an increased choline/creatine ratio, and a decreased N-acetylaspartate/creatine ratio. Our observations suggest that patients with MIDD may have subclinical neurologic dysfunction identifiable by proton MR spectroscopy.     

MRI of germinomas arising from the basal ganglia and thalamus

We reviewed the MRI findings of germinomas originating from the basal ganglia, thalamus or deep white matter in 13 patients with 14 germinomas, excluding those in the suprasellar or pineal regions. Ten cases were confirmed as germinomas by stereotaxic biopsy, three by partial and one by total removal of the tumour. Analysis was focussed on the location and the signal characteristic of the tumour, haemorrhage, cysts within the tumour and any other associated findings. Thirteen of the tumours were in the basal ganglia and one in the thalamus. Haemorrhage was observed in seven patients, while twelve showed multiple cysts. Associated ipsilateral cerebral hemiatrophy was seen in three patients. The signal intensity of the parenchymal germinomas was heterogeneous on T1- and T2-weighted images due to haemorrhage, cysts and solid portions. We also report the MRI findings of germinomas in an early stage in two patients. Received: 31 July 1997 Accepted: 6 January 1998     

Slow-growing labyrinthine masses: contribution of MRI to diagnosis, follow-up and treatment

We report the use of MRI in the diagnosis, follow-up and therapeutic management of three cases of intralabyrinthine Schwannoma. The diagnosis was based on the history and initial and follow-up MRI findings. The main feature suggesting the diagnosis was a nodular intralabyrinthine mass of low signal intensity on T2-weighted images, and high or isointense signal on T1-weighted images (relative to cerebrospinal fluid), which showed contrast enhancement. Follow-up imaging showed growth of the tumour in one patient. One patient underwent surgery for severe tinnitus. To detect these lesions, MRI should be focussed on the inner ear, using thin-section T2-weighted and T1-weighted images before and after contrast medium. MRI allowed informed surgical planning. Received: 26 March 1997 Accepted: 27 January 1998     

Solid-pseudopapillary tumor of the pancreas: MR imaging findings in 21 patients

PurposeSolid-pseudopapillary tumor (SPT) of the pancreas is a rare, low-grade malignancy, which mostly occurs in adolescent and young adult females. The goal of this study was to retrospectively analyze the magnetic resonance (MR) imaging presentation of SPT of the pancreas.MethodsWe retrospectively reviewed the preoperative MR imaging examinations and the medical, surgical and histopathological records of 21 patients who underwent surgery for SPT of the pancreas. MR imaging included T1-weighted, T2-weighted, and gadolinium chelate-enhanced MR imaging. In addition, 10 patients had diffusion-weighted (DW) MR imaging. MR examinations were retrospectively reviewed for location, size, morphological features and signal intensity of the tumors.ResultsNineteen women and 2 men (median age, 23 years; range, 14–59) were included. Seven patients (7/21; 33%) presented with abdominal symptoms. The median largest tumor diameter was 53mm (range, 32–141 mm). SPTs were located in the pancreatic head, body, and tail in 9 (9/21; 43%), 5 (5/21; 24%) and 7 (7/21, 33%) patients, respectively. All patients (21/21; 100%) had a single SPT. SPTs were more frequently oval (12/21; 57%), predominantly solid (12/21; 57%), fully encapsulated (16/21; 76%), larger than 30 mm (21/21; 100%), hypointense on T1-weighted MR images (21/21, 100%), hyperintense on T2-weighted MR images (21/21; 100%) and with an enhancing capsule after gadolinium-chelate administration (21/21; 100%).ConclusionsThere is trend of appearance for SPT of the pancreas on MR imaging but that variations may be observed in a number of cases. SPT uniformly presents as a single, well-demarcated and encapsulated pancreatic mass.     

Evolution of high-intensity basal ganglia lesions on T1-weighted MR in neurofibromatosis type 1.

PURPOSETo characterize the temporal evolution of the foci of T1 shortening in basal ganglia lesions in patients with neurofibromatosis type 1 (NF-1).METHODSA retrospective review of MR images of 37 patients with NF-1 revealed 8 patients in whom regions of T1 shortening were noted in the basal ganglia. We reviewed sequential images obtained in these selected patients with special attention to chronological changes in the foci of T1 shortening and their relationship to changes on T2-weighted images.RESULTSRegions of short T1 in the globus pallidus were observed in 8 patients. In 2 of 3 patients in whom foci of T1 shortening were not identified on the initial imaging study, T1 shortening developed and T2 prolongation diminished after an initial increase. In the third patient, T1 and T2 prolongation appeared simultaneously. Sequential scans in the other 5 patients, in whom areas of increased signal intensity in the globus pallidus were present on both T1-weighted and T2-weighted images on the initial MR examination, showed a diminution in the size of the region of T2 prolongation in 2 patients, an increase in the size of the region of T2 prolongation in 1 patient, a mixed pattern of change in the size of the region of T2 prolongation in 1 patient, and no change in the region of T2 prolongation in 1 patient. During the periods of these T2 changes, the areas of T1 shortening showed no significant interval change.CONCLUSIONThe foci of prolonged T2 relaxation in the basal ganglia appear to evolve in a manner similar to the foci of T2 prolongation in the white matter of the posterior fossa. However, the corresponding foci of short T1 in the basal ganglia may evolve with a different time course. In some patients, the foci of short T1 develop at a later time than the T2 prolongation and progress; these foci of short T1 do not appear to regress over periods as long as 90 months. Possible causes of the T1 shortening are remyelination and calcification.     

Fibro-osseous lesions involving the brain: MRI

We present the MRI findings in two patients with “fibro-osseous lesions” involving the central nervous system. A left temporal lobe mass was present in one patient and an extra-axial mass at the skull base in the other. In both cases, calcification was present, with low signal intensity on T1- and T2-weighted images. Received: 30 December 1997 Accepted: 10 June 1998     

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.     

Amyloid arthropathy of the hip joint: MR demonstration of presumed amyloid lesions in 152 patients with long-term hemodialysis

The aim of this study was to determine the spectrum of MR findings of presumed amyloid arthropathy of the hip joints in patients on long-term hemodialysis. We prospectively performed T1- and T2-weighted spin-echo imaging on 152 consecutive patients on hemodialysis. The duration of hemodialysis ranged from 5 months to 24 years, 2 months (mean: 8 years, 8 months). The frequency, location, and signal intensity of bone lesions were assessed. In 12 cases with contrast-enhanced MR examination, enhancement pattern of bone lesions, synovial lesions, and intra-articular lesions were characterized. Bone lesions presumed to be amyloid deposits were identified in 60 patients (39 %). Magnetic resonance imaging revealed that amyloid lesions were more extensive than anticipated by plain radiographs. All bone lesions showed decreased signal intensity on T1-weighted images. On T2-weighted images, bone lesions showed increased signal intensity in 32 patients (54 %), decreased signal intensity in 11 patients (18 %), and both increased and decreased signal intensity in 17 patients (28 %). Following intravenous injection of gadolinium-based contrast, all bone lesions showed moderate enhancement. Synovial thickening could not be identified on T1- and T2-weighted images. However, contrast-enhanced images showed thickened synovial membrane, which could be differentiated from joint fluid. Intra-articular nodules showed decreased or intermediate signal intensity on T1-weighted images and decreased signal intensity on T2-weighted images; the intra-articular nodules were contiguous with subchondral bone lesions. Magnetic resonance imaging is useful for evaluating the distribution and extent of amyloidosis of the hip joints in patients undergoing long-term hemodialysis. Received 5 August 1997; Revision received 22 October 1997; Accepted 11 February 1998     

CT and MRI of congenital sinonasal ossifying fibroma

We report a 9-year-old boy with a sinonasal ossifying fibroma, probably congenital, with atypical findings on CT and MRI. CT revealed a soft-tissue density mass in the sphenoethmoidal sinuses, nasal cavity and right maxillary sinus with a few foci of calcification and with remodelling and destruction of the adjacent facial bones. MRI showed high signal on T2- and intermediate signal on T1-weighted images. A thin, partly enhancing outer shell and some nonenhancing septa were visible on contrast-enhanced images. MRI also showed the tumour to extend into the anterior cranial fossa. Subtotal removal was performed. We compare our findings with reports in the literature and discuss the differences from fibrous dysplasia. Received: 30 September 1998 Accepted: 18 December 1998     

周围软组织血管瘤和血管畸形MRI鉴别诊断

目的探讨血管瘤和血管畸形MRI的鉴别诊断。方法回顾性分析61例手术证实的血管瘤和血管畸形MRI表现并与病理进行对照。结果29例血管瘤中,在T1WI上,20例为等信号(等于肌肉信号),9例为高等混杂信号;在T2WI上,24例呈较高信号(接近脂肪信号),5例呈高信号(高于脂肪信号),另见25例条状低信号分隔,其中4例增强呈分块状强化。32例血管畸形中,T1WI图,16例为等信号,16例为高等混杂信号;T2WI图,3例呈较高信号,29例呈高信号。其中15例增强呈不均匀强化。结论MRI对血管瘤和血管畸形的鉴别诊断有重要价值。     

Asymptomatic cerebral involvement in Sjögren's syndrome: MRI findings of 15 cases

Fifteen patients with Sjögren's syndrome without clinical evidence of central nervous system disease were studied by MRI. Signal abnormalities were observed in 9 (60%). They were always visible on T2-weighted images as small punctate areas of high signal in the basal ganglia and the white matter of the cerebral hemispheres. Abnormalities were less frequently seen on T1-weighted images. Enlargement of cerebral sulci was observed in 6 cases. The specificity and significance of these abnormalities are discussed.