Biomedical subjects
Publications and source records attributed to P Demaerel.
A rare case of central pontine myelinolysis and associated extrapontine myelinolysis is presented. The MR findings confirmed the observations reported in recent papers.
A case of fatal intracranial aspergillosis, extending from the sphenoid sinus via the orbit into the subarachnoid space of the optochiasmatic cistern and the cistern of the middle cerebral artery is presented in an immunosuppressed patient with multiple myeloma. Adequate treatment was not instituted and the patient died because the condition was not recognised and interpreted as a soft tissue extension of an orbital localization of myeloma. MRI, especially after intravenous injection of Gadolinium, depicted very accurately the extension of the disease, as defined at autopsy.
Thirty-seven patients with chronic low-back pain and an atypical irradiation to one or both legs were examined by conventional tomography of the facet joints. A disc herniation was excluded by computed tomography (CT) in 31 patients. The facet joints were considered normal in 4 patients. Four grades of facet joint disease were used to classify the pathological changes. Correlation of the radiological findings with the facet joint block by injection of a local anesthetic was obtained in 12 patients. It appears that conventional tomography is a very sensitive technique as it is possible to detect even discrete abnormalities of the facet joints. However, as it is time consuming and high in radiation dose, the examinations should be reserved for patients with a normal CT examination of the lumbar spine in whom there still remains a high suspicion of facet joint disease.
The etiology of hemiplegic cerebral palsy has been elucidated by surveys of affected children using CT. MR imaging has contributed to the more exact diagnosis of the nature and extent of hypoxic ischemic damage and allows the accurate estimation of the time of the insult. Serial MR imaging and MR spectroscopy may be useful for predicting the prognosis for cerebral palsy and neurodevelopmental delay. The damage caused by intrauterine infection is best appreciated on MR imaging, though CT is important in showing calcification. Similar considerations apply to tuberous sclerosis, and new observations may facilitate MR imaging diagnosis. Gadolinium-enhanced MR imaging is the most accurate modality for detection of tumor recurrence and metastatic spread. Enhancement due to reactions to and complications of surgery can usually be distinguished. The reliability of MR imaging in showing many congenital anomalies provides evidence of the incidence of these lesions and contributes to understanding the disordered embryology. Most of the changes described in inherited metabolic disorders are nonspecific, but they may suggest a particular diagnosis, and MR imaging is the most sensitive modality for monitoring progress. Lifesaving intervention for arteriovenous malformations involving the vein of Galen requires detailed noninvasive imaging for selecting the most effective approach. Technical developments in diffusion and in flow imaging promise to further increase our diagnostic capabilities and to limit the application of invasive techniques.
Localized proton spectroscopy of the brain was performed on MS patients (n = 18) and the results are compared with those of a control group (n = 17). The experiments were performed in a 1.5-T Siemens Magnetom using the stimulated echo method and selective water suppression. Acquisition parameters were TR/TE/TM = 3000/270/30 ms, NA = 256, and Acq = 13 min. Localized volumes ranged from 8 to about 80 cc. The patients (ages 25 to 66) were at various stages of the disease. Three of the eighteen patients did not show any plaques on the MR images. VOIs were chosen to contain as much plaque volume as possible in the cerebrum white matter. In the controls and in the patients with no plaques, the VOI were localized in similar white matter regions. All spectra were characterized by the presence of Cho (3.2 ppm), PCr + Cr (3.0 ppm), and NAA (2.0 ppm). The ratios NAA/Cho and NAA/(PCr + Cr) were calculated for both the MS and the control group. The results for the three MS patients with no detectable plaques did not differ significantly from the results of the control group. The former group is, however, too limited to draw any conclusion for the moment. For the MRI positive patients, the following values were found (means +/- 1 SD); NAA/Cho = 1.98 +/- 0.33 and NAA/(PCr + Cr) = 2.16 +/- 0.14. In the normals, these values were NAA/Cho = 2.54 +/- 0.39 and NAA/(PCr + Cr) = 2.76 +/- 0.25. The results quoted are TR and TE dependent.(ABSTRACT TRUNCATED AT 250 WORDS)
MRI was performed in 41 patients with ocular lesions: 27 cases of malignant melanoma, 5 of haemorrhage, 3 of choroidal metastasis, 3 of senile disciform macular degeneration, 2 retinoblastomas and 1 hamartoma. On MRI 5 small lesions (less than 2 mm thick): 1 melanoma, the 3 metastases and the hamartoma, were not seen. All the malignant melanomas visualised were hyperintense compared to the vitreous on T1-weighted images. On T2-weighted images 24 of 26 lesions were hypointense compared to the vitreous. The remaining two lesions were almost isointense, corresponding to amelanotic lesions. These MRI features did not differ significantly from those of retinoblastomas, senile disciform macular degeneration or subacute choroidal haemorrhage. Major shortcomings of MRI in lesions of the globe lie in a lack of spatial resolution and poor specificity of the findings.
The radiologic findings in a case of an extradural diploic epidermoid tumor (ET) of the frontal bone, examined with plain X rays, CT and MRI, are reported. A head injury with traumatic inclusion of epidermis could have been the origin of the tumor. This report stresses the importance of the plain skull X ray in the diagnosis of extradural ET.
Up to 5 years ago, the radiological diagnosis of leukodystrophy was based on computed tomography (CT). More recently, magnetic resonance imaging (MRI) has been used to study pathology of the white matter with great success. The abnormalities in eight patients with different types of leukodystrophy are described, using high-field MRI. CT and MRI show comparable sensitivity in detecting the pathological changes of leukodystrophy. MRI seems to be superior in visualizing the extent of the lesions, their precise anatomical location and any involvement of the brain stem and cerebellum. Differential diagnosis among the three types of leukodystrophy by MRI is difficult but may be attempted by some features. Specific diagnosis can be achieved only by laboratory examination or histology. The role of MRI should be to suggest the proper biochemical test at an earlier stage.
Two patients with ruptured intracranial dermoids, examined with both CT and MRI are reported. Clinical presentation was transient cerebral ischemia in one patient and acute meningeal signs in the other. CT scan showed typical fat density of the tumor and the subarachnoid space. On MRI both the tumor and the subarachnoid fat, were strongly hyperintense on T1-weighted images.
A case of a congenital nasolacrimal mucocele is reported. This very uncommon finding presents usually with a diagnostic triad on CT: an intranasal cystic mass, a dilated nasolacrimal duct and lacrimal sac.
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A case of isolated unilateral extraocular muscle myositis following an acute upper respiratory tract infection is reported. Painful eye movements, restricted eye motility and exophthalmus but a normal visual acuity are the most important clinical findings. High resolution contrast enhanced CT and MRI are the imaging modalities of choice to differentiate from other orbital pathologies. The solitary enlarged muscle was clearly seen on both the contrast enhanced CT and the MR examination. Preseptal cellulitis was better seen on MRI, whereas high resolution CT was superior in the demonstration of periscleritis. Graves' ophthalmopathy and orbital cellulitis first have to be excluded. Corticosteroids are the therapy of choice in orbital myositis. A control, contrast enhanced CT after 4 weeks showed an almost normal muscle.
A case of intracavernous aneurysm in a 56-year-old woman is reported. The superiority of MRI and MRA in the diagnosis is shown.
We report the case of a 16-year-old patient with osteopetrosis major, complaining of transient sensory and motor disturbances in the left upper limb and dizziness on changing the position of his head. Selective angiography of the cerebral vessels showed severe narrowing of the internal carotid artery within the petrous carotid canal and in its supraclinoid portion. The cervical vertebral arteries showed multiple stenosis within the vertebral canal. These findings are explained by narrowing of the basal foramina by the osteopetrotic bone.
The MR findings in an adult patient with globoid cell leucodystrophy (GLD) or Krabbe's disease are presented. MRI showed a bilateral periventricular hyperintensity of the parieto-occipital white matter on the T2-weighted images. A hyperintense signal was seen bilaterally along the corticospinal tract. There was no immediate nor delayed contrast enhancement. The MR findings in this case of GLD are rather atypical.
MRI findings in 3 cases of cerebral tuberculosis are reported. MR features consisted in meningeal enhancement, enhancement of the basilar cisterns and brainstem abscesses. T1 weighted images after intravenous administration of gadolinium appeared most efficient in the demonstration of the lesions.
The MRI appearance and evolution of hemorrhage remains a difficult entity. A typical example of the MR visualization of an intracerebral bleeding in the basal ganglia and the internal capsule at 1.5 T is presented. The sequential biochemical and physical changes in an hemorrhage are described.
Computerized tomography (CT) and magnetic resonance imaging (RMI) showed cortico-subcortical atrophy as well as calcification of the basal ganglia and the cerebellar dentate nuclei in a patient presenting with cerebellar syndrome. RMI was particularly useful in imaging the demyelination of the periventricular white matter and the subcortical U fibres. A diagnosis of Cockayne's syndrome was made. This is an extremely rare hereditary disease of unknown pathogenesis. Defective recovery of DNA synthesis has been suggested.