Langerhans' cell histiocytosis of the spine: use of MRI in guiding biopsy

The MRI features of two cases of spinal Langerhans' cell histiocytosis with multilevel involvement are presented in which MRI was of help in differentiating active from inactive healing lesions by the demonstration of signal changes in the vertebral body marrow of the active lesion, manifest as low signal intensity on T1-weighted sequences and high signal intensity on T2-weighted sequences. This distinction could not be made by plain radiography or bone scintigraphy. In cases where biopsy is required for diagnosis, MRI is recommended to guide the biopsy towards levels suggestive of active involvement.     

Contrast media-enhanced magnetic resonance imaging visualizes myocardial changes in the course of viral myocarditis

BACKGROUND: The course of tissue changes in acute myocarditis in humans is not well understood. Diagnostic tools currently available are unsatisfactory. We tested the hypothesis that inflammation is reflected by signal changes in contrast-enhanced magnetic resonance imaging (MRI). METHODS AND RESULTS: We assessed 44 consecutive patients with symptoms of acute myocarditis. Nineteen patients met the inclusion criteria revealing ECG changes, reduced myocardial function, elevated creatine kinase, positive troponin T, serological evidence for acute viral infection, exclusion of coronary heart disease, and positive antimyosin scintigraphy. We studied these patients on days 2, 7, 14, 28, and 84 after the onset of symptoms. We obtained ECG-triggered, T1-weighted images before and after application of 0.1 mmol/kg gadolinium. We measured the global relative signal enhancement of the left ventricular myocardium related to skeletal muscle and compared it with measurements in 18 volunteers. The global relative enhancement was higher in patients on days 2 (4.8+/-0.3 [mean+/-SE] versus 2.5+/-0.2; P<.0001); 7 (4.7+/-0.5, P<.0001); 14 (4.6+/-0.5, P<.0002); and 28 (3.9+/-0.4, P=.009) but not on day 84 (3.1+/-0.3; P=NS). On day 2, the enhancement was focal, whereas at later time points, the enhancement was diffuse. In patients with evidence of ongoing disease, the values remained elevated. CONCLUSIONS: Acute myocarditis evolves from a focal to a disseminated process during the first 2 weeks after onset of symptoms. Contrast media-enhanced MRI visualizes the localization, activity, and extent of inflammation and may serve as a powerful noninvasive diagnostic tool in acute myocarditis.     

High signal intensity of globus pallidus on T1-weighted MRI in liver cirrhosis patients: clinical and pathological study

In some patients with liver cirrhosis, the globus pallidus shows high signal intensity on T1-weighted MRI. The relationship was examined between high signal intensity on T1-weighted images and pathological conditions such as liver function, portal venous pressure and metal concentrations in brain. The signal of the globus pallidus on T1-weighted imaging became highly enhanced in accordance with prolongation of prothrombin time, deterioration of ICG R15, or decrease in choline esterase and the Fisher ratio. Furthermore, the high signal intensity was also seen in patients with high portal pressure and large varices. In histopathological study, remarkable atrophy and loss of nerve cells were observed in globus pallidus with high signal intensity on T1-weighted imaging, changes that were similar to those in with patients with manganese poisoning. The manganese concentration in autopsied globus pallidus with high signal intensity on T1-weighted imaging showed a 9.5-fold increase compared with that with normal intensity. In conclusion, the deposition of manganese in the globus pallidus, which is accompanied with the nerve cell deciduation, brings about the high signal intensity of the globus pallidus on T1-weighted MRI in patients with liver cirrhosis.     

Effectiveness of slow-release lanreotide, a long-acting somatostatin analogue, in the treatment of acromegaly

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.     

MRI and clinical features in amyotrophic lateral sclerosis

MRI of the brain and spinal cord was performed in 21 patients with amyotrophic lateral sclerosis (ALS), 8 normal volunteers and 16 neurological disease controls. High signal was seen in the intracranial corticospinal tract in 16 of the 21 patients on T2-weighted and in 10 on proton density (PD)-weighted images. In one patient, the high signal on T2-weighted images became less marked with progression of the disease. Low signal intensity was seen in the motor cortex in 12 of the 21 patients. High signal in the anterolateral column of the spinal cord on T1 weighted images was seen in 14, and high signal in the lateral corticospinal tract on T2 weighted images was seen in 7 of the 21 patients. The relationship between the abnormal images and upper motor neurone signs remained unclear. High signal intensity was seen in the corticospinal tract in the brain on T2-weighted images in two normal volunteers and four disease controls, and on PD weighted images in three disease controls. Low signal intensity in the motor cortex on T2 weighted images was seen in three normal volunteers and four disease controls. However, high signal intensity was seen in the intracranial corticospinal tract on T1 weighted images in five patients with ALS who showed pronounced upper motor neurone signs including spastic paraparesis, but not in controls. Thus, abnormalities on MRI in the brain and spinal cord should be considered in the diagnosis of ALS, and high signal intensity of the intracranial corticospinal tract on T1-weighted images may reflect the severe pathological changes of the upper motor neurones in ALS.     

Transient osteoporosis of the knee

The MR findings in transient osteoporosis of the knee have been described as showing a diffuse area of decreased signal intensity (relative to normal bone marrow) on T1-weighted images and increased signal intensity on T2-weighted images. We report a case of transient osteoporosis, in which MRI showed a crescentic area of abnormal signal intensity in the posterior portion of the lateral femoral condyle, which was bordered by a rim of low signal intensity, best seen on the T2-weighted images. This abnormality was shown to resolve on follow-up MR scans.     

Severe right ventricular dysfunction in a neonate with aortic origin of the RPA

A 77-year-old man had rapidly increased intramuscular tuberculous abscess in his left buttock. Radiographs showed a bone defect in the left ischium. Postcontrast CT scanning revealed marginal enhancement. MR imaging showed low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. T1-weighted MR images with Gd-DTPA enhancement showed enhancement of the wall. Bone defect and marginal enhancement on postcontrast MR images and on postcontrast CT images are image character of the intramuscular tuberculous abscess.     

Mutators and long-term molecular evolution of pathogenic Escherichia coli O157:H7

We report the MRI features and correlative pathologic findings of a lung cancer in a patient with progressive massive fibrosis (PMF). In this case, MRI was able to distinguish the lung cancer as a high signal intensity area, and the fibrotic mass as a low signal intensity area, on both T1-weighted and T2-weighted images when compared with muscle. MRI is potentially useful in distinguishing cancer tissue from PMF in patients with pneumoconiosis.     

MR imaging of intramuscular hemangiomas

Magnetic resonance images of eight surgically confirmed intramuscular hemangiomas were correlated with the pathologic findings. T1- and T2-weighted images were obtained in all cases; STIR images were also obtained in six cases, and fat-suppressed enhanced images in seven cases. All eight hemangiomas showed markedly high signal intensity on T2-weighted images. Linear and round low-signal-intensity components within hemangiomas corresponded to fibrous tissues, high flow vessels and phleboliths. Fat-suppressed enhanced images were superior to images without fat suppression in defining the extent of lesions. STIR images were useful in defining the extent of hemangiomas with infiltration into surrounding tissues. MRI is useful for distinguishing intramuscular hemangiomas from other soft tissue tumors and also supplies valuable information about the extent of the lesions.     

Detection of hepatic tumors: arterial-phase MR imaging versus spiral CT arteriography

BACKGROUND: Distinction between uncomplicated infective fasciitis and early necrotizing fasciitis can be extremely difficult without operation, yet the management and prognosis of both conditions depend greatly on early recognition and assessment of the extent of involvement. STUDY DESIGN: This was a prospective review of the utility of magnetic resonance imaging (MRI) in nine patients with suspected infective or necrotizing fasciitis treated at an academic medical center or a Veterans Administration hospital. RESULTS: Magnetic resonance imaging documented fascial inflammation, characterized by low intensity on T1-weighted images and high intensity on T2-weighted images, in all nine patients. Absence of gadolinium contrast enhancement on T1-weighted images reliably detected fascial necrosis in all six patients who required operative debridement. Magnetic resonance imaging was extremely useful in defining the extent of fasciitis and was more accurate in predicting necrosis or pyomyositis than was myoglobinuria or elevation of serum creatine kinase or lactate dehydrogenase. Operation was avoided in two patients without evidence of necrosis on MRI. One patient without evidence of necrosis, explored because of contradictory clinical findings, was confirmed at operation to have cellulitis without necrosis. CONCLUSIONS: Magnetic resonance imaging with gadolinium contrast accurately determines the presence of necrosis and the need for operation in patients with fasciitis of the lower extremity. Preoperative determination of the extent of involvement facilitates operative planning.     

Increased gene transfer into human CD34+ progenitor cells using retroviral vectors produced by a canine packaging cell line

Magnetic resonance imaging (MRI) was used in 13 patients with peripheral lymphedema and 2 patients with extensive cavernous lymphangioma of the limb for the purpose of evaluating its role in diagnosis of lymphatic disorders. In chronic lymphedema, MRI showed deformity of lymphatics at different tissue levels. In the subcutis, MRI characteristically displayed diffuse edema or a honeycombed pattern consistent with reticular lymphangiectasis and "lakes" with a marked increase in signal intensity with T2-weighted imaging. In lymphedema hyperplasia and chylous reflux, MRI depicted dilated retroperitoneal lymphatic collectors and lumbar trunks. In cavernous lymphangiomatosis, MRI demonstrated a prominent lattice-like pattern which had lower signal intensity on T1-weighted imaging and higher intensity on T2-weighted imaging. The findings of MRI are valuable not only for accurate assessment of lymphatic dysplasia syndromes but also provide a blueprint for treatment options.     

Radiation myelopathy: a clinicopathological study with special reference to correlation between MRI findings and neuropathology

We describe magnetic resonance imaging (MRI) and neuropathological findings in a patient with chronic progressive radiation myelopathy (CPRM). An 81-year-old man with esophageal cancer underwent radiotherapy. Four years later he developed a progressive neurological deficit below the irradiated level of the spinal cord. Neurological examination revealed spastic paraplegia. MRI findings showed an area of high signal intensity on T2-weighted images of the thoracic spinal cord. On the basis of clinical and MRI findings, we diagnosed his condition as CPRM. MRI performed thirteen months after onset of neurological signs revealed mild atrophy of the spinal cord detected on T1-weighted images and an area of high signal intensity within the spinal cord detected on T2-weighted images. Neuropathological examination revealed findings consistent with radiation myelopathy. We speculate that the area of high signal intensity within the spinal cord detected on T2-weighted images might be a result of proliferation of small vessels, which was discovered upon autopsy.     

Detection of glomus tumor of the finger by dedicated MRI at 0.1 T

Three glomus tumors of the fingers were detected using a dedicated hand and wrist low field (0.1 T) MR imager equipped with solenoidal coils allowing a FOV of 2 cm. Three-dimensional T1-, T*2-, or T2-weighted images were used (8 contiguous slices of 2 mm thickness). Glomus tumors had low or intermediate signal intensity (2 cases) or no signal (1 case) on T1-weighted images. On T*2- or T2-weighted images they had high signal intensity. MRI findings correlate well with surgery and biopsy.     

Post radiation hemorrhagic cystitis: MR findings

We report on the magnetic resonance findings in two patients with hemorrhagic cystitis secondary to radiation therapy. One patient's bladder wall was high in signal intensity on T1-weighted fat-suppressed spoiled gradient echo and low in signal intensity on T2-weighted fat-suppressed spin echo images, findings consistent with intracellular methemoglobin in the setting of subacute intramural hemorrhage. The second patient's bladder wall had regions that were low in signal intensity on T1-weighted fat-suppressed spin echo and high in signal intensity on T2-weighted fat-suppressed spin echo, and other regions that were high in signal intensity on T1-weighted fat suppressed spin echo and on T2-weighted fat-suppressed spin echo images, findings that were consistent with active bleeding and late subacute hemorrhage, respectively. Imaging findings correlated with the patients' clinical picture. Our two cases illustrate that magnetic resonance images may demonstrate changes of hemorrhagic cystitis and may permit determination of disease acuity.     

Survival of Vibrio spp. including inoculated V. cholerae 0139 during heat-treatment of cockles (Anadara granosa)

Six healthy adult male mongrel dogs underwent cranial cruciate ligament transection in the left stifle. Survey radiography of both stifles and low-field (0.064 T) MRI of the left stifle were performed preoperatively and at 2, 6, and 12 weeks postoperatively. Focal changes in signal intensity were seen with MRI in the subchondral bone of the medial tibial condyle at 2 and 6 weeks postoperatively. At 12 weeks postoperative, a cyst-like lesion was detected using MRI in the subchondral bone of the medial tibial condyle in 4 of 6 dogs and a less defined lesion at this site in the remaining 2 dogs. The cyst-like lesion was spherical in shape and showed typical characteristics of fluid with low signal intensity on T1-weighted images, high signal intensity on T2-weighted images and high signal intensity on inversion recovery images. The lesion was seen in the subchondral bone of the caudal medial and/or middle region of the tibial plateau slightly cranial to the insertion of the caudal cruciate ligament. No subchondral cysts were seen in the tibia on radiographs. Histopathologically, the tibia was characterized by a loose myxomatous phase of early subchondral cyst formation.     

Magnetic resonance imaging of lower extremity muscles and isokinetic strength in foot dorsiflexors in patients with prior polio

The thigh and lower leg of six patients with prior polio were examined using magnetic resonance imaging (MRI), and the strength of their weak foot dorsiflexors was measured isokinetically. Spinecho images of the lower extremities were visually evaluated on a semi-quantitative four-point scale, and T1 and T2 relaxation times of the lower leg anterior compartment were analysed. There were prominent MRI signs of randomly distributed muscle degeneration. The high signal intensity changes in the affected muscles on T1-weighted images and T1 and T2 values indicated replacement of muscle fibres with fat and the accumulation of tissue water, respectively. MRI findings were compared with isokinetic strength in foot dorsiflexor muscles. Foot dorsiflexor peak torque values at 30 deg/s ranged from 6 to 29 Nm. There was no significant correlation between MRI visual scoring, T1 and T2 relaxation times and peak torque values at 30 deg/s. However, the most severe MRI changes with visual scoring and T2 relaxation times were observed in the patients with the most pronounced muscle weakness.     

Fetal intracranial hemorrhage. Imaging by ultrasound and magnetic resonance imaging

OBJECTIVE: To describe the magnetic resonance imaging (MRI) findings associated with fetal intracranial hemorrhage and to compare them with ultrasound findings. STUDY DESIGN: In four pregnancies complicated by fetal intracranial hemorrhage, fetal imaging was carried out using T2-weighted fast spin echo sequences and T1-weighted fast low angle shot imaging sequences and by transabdominal ultrasonography. RESULTS: An antepartum diagnosis of hemorrhage was made by ultrasound in one case and by MRI in two. Retrospectively, the hemorrhagic area could be identified from the MRI images in an additional two cases and from the ultrasound images in one case. In the cases of intraventricular hemorrhage, the MRI signal intensity in the T1-weighted images was increased in the hemorrhagic area as compared to the contralateral ventricle and brain parenchyma. In a case with subdural hemorrhage, T2-weighted MRI signals from the hemorrhagic area changed from low-to high-intensity signals during four weeks of follow-up. Better imaging of the intracranial anatomy was possible by MRI than by transabdominal ultrasonography. CONCLUSION: MRI can be used for imaging and dating fetal intracranial hemorrhages. Variable ultrasound and MRI findings are associated with this complication, depending on the age and location of the hemorrhage.     

MRI of the pituitary adenomas with reference to the hormonal activity

Many studies in Magnetic Resonance Imaging (MRI) of pituitary adenomas are already performed. However, few reports exist about MRI findings of pituitary adenomas with reference to the hormonal activity, therefore, we evaluated this problem on the viewpoint of the signal intensity in MRI and pathological features. Fifteen patients with growth hormone producing adenoma (GH-group), 6 patients with prolactin producing adenoma (PRL-group), 15 patients with endocrinologically non-functioning adenoma (Null-group) and 9 cases with normal pituitary gland (normal control group) were examined. Signal intensity values in adenoma (or anterior lobe in normal control group) and in pons as standard value were measured in each cases, then their rates were calculated as signal intensity ratio (SIR). In 24 cases (14 in GH-group, 3 in PRL-group, 7 in Null-group), cellular density were examined with surgically resected specimens. In the T1-weighted images (T1 WIs), PRL-group and Null-group presented more hypointense tendency than normal control group. In the T2-weighted images (T2 WIs), only Null-group presented more hyperintense tendency than other groups. But significant correlation was not observed between SIR and cellular density.     

Pigmented Bowen''s disease

PURPOSE: The purpose of this study was to evaluate the temporal changes of MR imaging in the denervated tongue after a radical neck dissection. METHODS: One hundred seventy-four consecutive MR studies in 116 patients with radical neck dissections for malignant tumors of the head and neck were evaluated retrospectively. Patients with tumors involving the tongue or hypoglossal nerve were not included in this study. RESULTS: Abnormal signal intensity and/or hemiatrophy on the side of the tongue operated on was seen in 22 patients who had hypoglossal paralysis after radical neck dissection. The denervated side of the tongue appeared hypointense to hyperintense relative to the normal side on T1-weighted images and hyperintense on T2-weighted images. Signal intensity ratios of the abnormal to normal muscles were 0.9-1.6 on T1-weighted images and 1.3-2.8 on T2-weighted images. High signal intensity on T1-weighted images appeared 5 months or more after the dissection, whereas on T2-weighted images, the most prominent increases in signal intensity appeared in the first several months after denervation. Hemiatrophy of the tongue was observed on MR images obtained more than 6 months after surgery. CONCLUSION: MR findings in the denervated tongue are compatible with histologic changes and are characterized by an enlarged extracellular fluid space or fatty infiltration. The pattern of signal intensity and the degree of hemiatrophy suggest the duration of denervation.     

Calbindin-D28k is regulated by adrenal steroids in hypothalamic tissue during prenatal development

We report the case of a 42 year-old woman with amyotrophic lateral sclerosis (ALS). Neurological examination showed spastic paraparesis and muscular atrophy of the upper extremities. Increased signal intensity areas were present in the lateral corticospinal tract of the brain and cervical spinal cord on a T2-weighted image. Decreased signal intensity of the motor cortex on the T2-weighted image appeared during the course of the illness. SPECT showed hypoperfusion confined to the motor cortex. The area of increased signal intensity in the cervical spinal cord on the T2-weighted MR images extended to the anterolateral columns of the spinal cord. The area of hypoperfusion in SPECT extended to the fronto-parietal area with the progression of the disease. These changes in the MRI and SPECT findings may reflect progressive degeneration of the upper motor neurons in ALS.