Biomedical subjects
Publications and source records attributed to A Gaston.
A 53-year-old patient with Wilsons's disease and without autonomic dysfunction presented on T2-weighted MR study an atypical decreased signal intensity of the putamina and the caudate nuclei. Possible explanations of such a signal abnormalities are discussed.
A new device, modified from the Nucleotome (Surgical Dynamics, Alameda, CA), was used for stereotactic aspiration of deep brain hematomas. Real-time monitoring by computed tomography allows a very safe procedure, and the risk of aspirating the surrounding brain is avoided. The technique was applied in 13 cases of deep brain hematomas. The intraoperative computed tomographic scan demonstrated that the mass effect was always immediately improved. Aspiration was stopped when the midline shift disappeared or was dramatically reduced. For most of the cases, a total aspiration of the hematoma was not needed (mean value of the aspiration rate of 71, 5%). No rebleeding and no complication related to the technique was observed. This technique was easily performed in emergency conditions.
A case of multiple vertebral hemangiomas with progressive neurological deficit is presented. Successful treatment was accomplished using preoperative embolization, palliative surgical decompression, and postoperative radiation therapy. The patient has remained asymptomatic for 6 years. The authors review the role of current imaging modalities and options for therapeutic intervention. Preoperative embolization, palliative surgical decompression, and postoperative radiotherapy appear to provide a satisfactory outcome in patients with multiple hemangiomas and may represent an effective alternative to more aggressive surgical intervention.
The authors report their preliminary experience concerning the endovascular treatment of ruptured subarachnoid aneurysms during the acute phase in 9 patients. The endovascular approach was only used in Hunt and Hess grade IV or V patients, as an alternative to surgical clipping and in cases considered technically difficult for surgery (extremity of the basilar artery). No particular technical difficulties were encountered, except for a case with vasospasm. Further experience is needed to evaluate the benefit of this method during the acute phase.
The case of a female patient with two traumatic aneurysms diagnosed by serial angiography is reported. The first aneurysms, located on the orbito-frontal branch of the left anterior cerebral artery, was removed. The second aneurysm involving the right middle meningeal artery was treated by endovascular embolization. The causes and physiopathology of such lesions are reviewed. The frequency of traumatic cerebral aneurysms has been reduced by the routine use of computed tomography. Aggressive treatment of these aneurysms is advocated because of their natural history.
A 25-year-old homosexual AIDS patient presented with progressive cognitive, motor and behavioral disturbances consistent with HIV encephalopathy. CT scans demonstrated progressive diffuse brain atrophy. Neuropathology showed predominant cortical changes including severe neuronal loss corroborated by morphometry. Only minimal changes were found in the white matter and basal ganglia. Immunocytochemistry for HIV stained occasional microglial cells more markedly in the cerebral cortex. This suggests that HIV infection of the brain may cause predominant cortical nerve cell loss, and that HIV encephalopathy is not necessarily due to white matter lesions.
Among 121 intracerebral aneurysms presenting at one institution between 1984 and 1989, 16 were treated by endovascular means. All 16 lesions were intradural and intracranial, and had failed either surgical or endovascular attempts at selective exclusion with parent vessel preservation. The lesions included four giant middle cerebral artery (MCA) aneurysms, one giant anterior communicating artery aneurysm, six giant posterior cerebral artery aneurysms, one posterior inferior cerebellar artery aneurysm, one giant mid-basilar artery aneurysm, two giant fusiform basilar artery aneurysms, and one dissecting vertebral artery aneurysm. One of the 16 patients failed an MCA test occlusion and was approached surgically after attempted endovascular selective occlusion. Treatment involved pretreatment evaluation of cerebral blood flow followed by a preliminary parent vessel test occlusion under neuroleptic analgesia with vigilant neurological monitoring. If the test occlusion was tolerated, it was immediately followed by permanent occlusion of the parent vessel with either detachable or nondetachable balloon or coils. The follow-up period ranged from 1 to 8 years. Excellent outcomes were obtained in 12 cases with complete angiographic obliteration of the aneurysm and no new neurological deficits and/or improvement of the preembolization symptoms. Four patients died: two related to the procedure, one secondary to rupture of another untreated aneurysm, and the fourth from a postoperative MCA thrombosis after having failed endovascular test occlusion. The angiographic, clinical, and cerebral blood flow criteria for occlusion tolerance are discussed.
In this retrospective study twelve histologically confirmed cases of spinal chordoma have been reviewed. Plain radiographs were performed in all cases, and CT scans in 11 patients. Four patients had post-myelography CT. Five patients were explored by MRI, and two had a post-DOTA-gadolinium MR study. Ten patients underwent spinal arteriography. Cervical spine chordomas (3 cases) were osteolytic, developed laterally to the vertebral body and involved one of more adjacent vertebrae. Thoracic and lumbar chordomas (9 cases) were usually centrally located in the vertebral body with no adjacent involvement and presented as osteo-sclerotic or mixed osteolytic-osteosclerotic lesions. CT scans provide a good view of the extravertebral component of the tumour, but MRI is the best imaging method to evaluate tumoral extension. Intravenous gadolinium injection seems to produce a better delineation of the epidural extent of the tumour at cervical level. Angiography remains useful for presurgical evaluation.
The authors report the results of 89 vertebral biopsies performed under CT guidance, classified according to the type of pathology and the site of the lesion. A correct diagnosis was obtained in 89 cases. No complication was observed. The value of CT guidance in vertebral biopsy is emphasized.
A case of tuberculosis of the vertebral arch, with CT and MR studies is presented. A large necrotic paravertebral extension better shown on gadolinium enhanced MR study, may be helpful to suggest the diagnosis which must be confirmed by vertebral biopsy.
15 cases of supratentorial intracerebral hematomas (12 cases of primary hematomas and 3 post-traumatic cases) were operated under C.T. scan control, using the screw and suction technique (Backlund's needle). 10 cases of primary hematomas were operated early, before the 24th hour. The patients were selected for intervention on the following criteria: 1) Patients aged less than 70 years old; 2) initial Glasgow coma scale between 6 and 10; 3) cases with involvement of the mesencephalon by the hematoma were excluded. In the 3 cases of post-traumatic hematomas, intervention was decided in reference to the clinical course. The volume of the hematomas ranged from 40 to 160 cc. Putaminal or thalamic hematomas were observed in 9 cases. The percentage of aspirated hematoma volume ranged from 50 to 91%, the average being 70.5%. Dramatic improvement of the consciousness was observed in all cases. Improvement of the motor deficit was incomplete, for the most part. 1 patient rebled and 1 patient died (6.6% mortality). In 26% of the cases (4 patients) the development of a brain oedema, in the surrounding of the residual hematoma site, was observed during the post operative follow up. There was no post operative infection. Intervention under direct C.T. control allows an accurate guidance of the needle. Efficacity of the evacuation is attested by an immediate improvement of the mass effect on C.T. scan. Under C.T. control the risk to aspirate the adjacent brain is avoided. The technique proposed here has been easily performed in emergency condition.
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A case of an anterior cervical spinal artery originating from a right vertebral artery with a bifid origin is presented. Such an origin may have important surgical consequences, and must be evokated when the vertebral artery enters the cervical canal at an unusual level.
Analysis of a series of 14 cases of obliterative radiation arteriopathy was carried out in order to study the clinical features, symptomatology and the results of appropriate therapy. This demonstrated that the diagnosis is often missed due to the time interval since radiation and that on the contrary the diagnosis should only be considered in precise circumstances in terms of the delay and localisation superimposed on the irradiated zone with respect of other non-irradiated zones. Diagnosis requires double investigation both in terms of the arterial disease and associated post-radiation lesions and also in terms of the malignant disease, its progression and treatment. Arterial surgery is fraught with difficulty due to sclerosis and other specific problems: skin closure problems, and in the case of a prosthesis, anastomotic breakdown and superinfection. These dangers should not be underestimated even if in the series presented there were no serious postoperative complications. The indication for surgery should therefore be carefully considered: best avoided in asymptomatic forms, dilatation for short lesions and revascularisation for widespread and symptomatic lesions, while choosing the most appropriate revascularisation procedure. Radiation arteritis should be better understood by radiotherapists who should pay attention to preventive measures and advise systematic screening after three years.
Four patients with AIDS presented with a rapidly fatal global neurological illness. CT did not show any focal lesion and gross post mortem examination of the brain was normal in three of the four cases. Microscopic examination revealed numerous widespread microglial nodules in the brain parenchyma, most containing central toxoplama cysts or free tachyzoites. Such diffuse, non-necrotic, "encephalitic" forms of cerebral toxoplasmosis appear unique to AIDS and, to our knowledge, have not been documented previously. They represent a treatable, often misdiagnosed cause of diffuse neurological involvement in AIDS patients.
In vivo dual wavelength differential spectrography was performed on the hand of an adult male, using a collimated transillumination device. A pulsed laser with sufficiently high peak power and sufficiently low energy was employed so that transillumination could be realized without thermal damage. Spectrochemical analysis based on the absorbance of oxygen transporting molecules (OTM), i.e. haemoglobin in blood vessels and myoglobin in muscles, was performed along a 70 mm scanning line within the near-red infrared range. The two wavelengths used (675 and 800 nm) were chosen on the basis of the absorption spectrum of haemoglobin. The profiles computed with differential spectrography data related to the oxygen saturation of OTM are closely correlated with X-ray densitometry of the most vascularized tissues in the hand along the scanning line. In addition, at 675 nm, the profiles are rapidly modified as a function of the oxygen supply to the hand. Considering the accuracy obtained for the spatial localization of the OTM redox state, it is expected that these results could be applied to imaging.
From a serie of ten cases of compressive vertebral hemangiomas (H.V.C.), the interest of different imaging methods was evaluated. CT scan and M.R.I. were the best imaging modalities in most cases. A CT guided biopsy was necessary in three cases to differentiate from metastasis. Angiography permitted to establish the vascular patterns and to evaluate the usefulness of embolization performed in six cases.
CT scan and M.R.I. features have been evaluated in case of compressive (H.V.C.) and asymptomatic (H.V.A.) vertebral hemangiomas. The main datas observed in H.V.C. are: 1) thoracic localization; 2) whole vertebral body involvement; 3) extension to the pedicles; 4) irregular trabeculation; 5) swelling of bone contours with 6) epidural and perivertebral extension. H.V.C. always exhibit at least three of these six datas while H.V.A. are associated with 2 or less. Also H.V.C. frequently present intravertebral contrast enhancement on CT and low signal intensity on T1 weighted and high signal intensity on T2 weighted M.R.I.