technetium-tc-99m-exametazime and Brain-Edema

Hypoperfusion on single-photon emission computed tomography (SPECT) of the stroke-like lesion (SLL) at the hyperacute stage of mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) is considered to be a supportive evidence of the mitochondrial angiopathy theory. Our objectives were to examine whether other neuroimages, especially transcranial color-coded sonography (TCCS), done at the hyperacute stage of stroke-like episode (SLE) is consistent with hypoperfusion of the SLL. We reviewed the magnetic resonance imaging (MRI), SPECT, cerebral angiography, and TCCS of a patient with MELAS syndrome, all of which were performed at the hyperacute stage of one SLE. MRI on the 1st day post SLE showed right temporoparietal lesion with vasogenic edema. SPECT on the 2nd day showed focal decreased uptake of technetium-99m hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) in the same region, but cerebral angiography and TCCS on the 3rd day showed increased regional cerebral blood flow (rCBF) and distal arteriole dilation in the same region. TCCS can delineate increased rCBF of the SLL at the hyperacute stage of SLE. We propose that the discrepancy between the decreased (99m)Tc-HMPAO uptake and increased rCBF might be caused by mitochondrial dysfunction. The phenomenon of "hypoperfusion" on SPECT might be caused by cell dysfunction but not decreased rCBF. We suggest that SPECT can be complemented by angiography and TCCS in future studies to delineate the perfusion status of SLLs.

Topics: Adult; Brain Edema; Cerebral Angiography; Cerebrovascular Circulation; Humans; Hyperemia; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; MELAS Syndrome; Middle Cerebral Artery; Perfusion; Radiopharmaceuticals; Stroke; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Ultrasonography, Doppler, Transcranial

Ancillary testing is frequently required in the determination of death by brain criteria, particularly in cases in which the clinical examination is drawn into question. Newer tests, such as computed tomographic angiography (CTA), have garnered enthusiasm for their ease of performance, but have not been validated as acceptable tests compared with a gold standard.. We present a case of a 31-year-old patient who was felt to have cerebral circulatory arrest on CTA, but was subsequently found to have evidence of preserved cerebral blood flow on transcranial Doppler, thus precluding the diagnosis death by brain criteria.. CTA is not a validated confirmatory test for cerebral circulatory arrest in brain death, and may be falsely positive.. CTA should be studied further in comparison to validated tests, such as conventional angiography or single photon emission computed tomography (SPECT), before being accepted as a standard ancillary test in determining death by brain criteria.

Topics: Adult; Brain Death; Brain Edema; Cerebral Angiography; Cerebrovascular Circulation; Circle of Willis; Diagnosis, Differential; Electroencephalography; False Positive Reactions; Female; Heart Arrest; Humans; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Ultrasonography, Doppler, Transcranial

Carbon monoxide (CO) is a common cause of poisoning, and its sequelae include a progressive (25%) and a delayed relapsing form (75%). We report the diffusion-weighted MRI (DWI) findings in the delayed relapsing form of CO poisoning and characterize the types of edema.. From November 1, 2000 to June 1, 2003, 5 consecutive patients (2 men, 3 women, range of age: 54-67 years), who had the delayed relapsing type of CO poisoning, underwent DWI, conventional MRI, MR angiography and SPECT. CO poisoning was diagnosed by the presence of a typical clinical history, an abnormally increased level of serum carboxyhemoglobin and MRI findings. Apparent diffusion coefficient (ADC) values were measured in all of the abnormal lesions with visual inspection of DWI and T(2)-weighted echo-planar imaging.. DWI showed high signal intensities in bilateral periventricular white matter, in the splenium of the corpus callosum, in internal capsules, and brainstem showing moderately decreased ADC values. In the globus pallidus, the ADC values were rather increased with low signal intensities on DWI. Brain SPECT showed decreased perfusion in bilateral white matter and some parts of the cerebral cortex, which correlated well with the DWI findings.. We suggest that prominent, symmetric restricted diffusion can occur in periventricular white matter, brainstem, and corpus callosum after the delayed relapsing type of CO poisoning. Delayed cytotoxic edema can occur in this setting, which provides a new guidance for the pathogenesis of CO poisoning and the differential diagnosis of white matter diseases.

Topics: Aged; Brain Edema; Brain Mapping; Carbon Monoxide; Carbon Monoxide Poisoning; Diffusion Magnetic Resonance Imaging; Female; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Lack of an effective treatment for spontaneous intracerebral haemorrhage (ICH) is partly because the mechanism of neuronal damage in ICH is not fully understood. Animal experiments have shown that there is a zone of ischaemia and oedema around the haematoma which can be reduced by early evacuation of the mass lesion. We set out to study Cerebral Blood Flow (CBF) changes in patients with ICH. We present data on 13 patients (mean age 60). SPECT scans were performed within 48 hours of ictus and 4-7 days later. Four patients had surgical evacuation of the clot; 9 were managed conservatively. The ratio of uptake of the isotope in the cerebral hemisphere containing the haematoma to the isotope uptake in the contra-lateral (un-affected) cerebral hemisphere was taken as an index of perfusion of the affected cerebral hemisphere. The perfusion index of the affected hemisphere improved between the first and the second scans in all the surgically treated patients; in the conservatively managed group, it was worse in 6 patients, the same in 1 and very slightly better in 2. There was an overall mean improvement of 3.87% in the surgical group, and an overall mean deterioration of 3.61% in the medical group. This data suggests that surgical evacuation of the clot may improve perfusion in the ipsilateral cerebral hemisphere in ICH. It underlines the importance of a prospective randomised trial to assess the value of surgery in patients with ICH. The Surgical Trial in Intracerebral Haemorrhage (STICH) is currently underway worldwide. We also describe the application of Difference Based Region Growing (DBRG) to SPECT image analysis. This method overcomes the difficulties posed by 1) the presence of a mass lesion and 2) surgical evacuation of haematoma.

Topics: Brain; Brain Edema; Cerebral Hemorrhage; Female; Humans; Male; Middle Aged; Postoperative Complications; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

The effects of peritumoural oedema on cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were studied in 18 patients with alert consciousness. Hemispheric mean CBF was measured by performing first-pass radionuclide angiography using technetium-99m hexamethylpropylene amine oxime. CVR was measured as the percentage change from the baseline mean CBF value after acetazolamide administration. Patients were classified into three groups according to the severity of peritumoural oedema. The mean CBF of both hemispheres in each group was not significantly different from that of age-matched controls. CVR was preserved in patients with mild peritumoural oedema (n=6), but was significantly (P<0.01) reduced in patients with moderate (n=7) and severe peritumoural oedema (n=5). No significant correlation was found between the degree of midline shift and the mean CVR of both hemispheres (P=0.09). Surgical removal of the tumour significantly (P<0.05) improved the impaired CVR, although the mean CBF did not change. Administration of glucocorticoid improved the impaired CVR, without a change in the mean CBF, in a patient with a metastatic brain tumour. We conclude that CVR is impaired by the development of peritumoural oedema prior to changes in mean CBF.

Topics: Acetazolamide; Brain; Brain Edema; Brain Neoplasms; Cerebrovascular Circulation; Consciousness; Diuretics; Female; Humans; Male; Middle Aged; Radionuclide Imaging; Radiopharmaceuticals; Technetium Tc 99m Exametazime

A heart transplant patient treated with OKT3 developed a severe headache which worsened and was accompanied by a sudden decrease in the patient's consciousness level and aphasia when the treatment course was completed. CT was performed and was normal. SPET imaging with 99mTc-HMPAO of cerebral blood flow done 16 hours later revealed multiple and clear focal defects in the blood flow. Analysis of cerebral spinal fluid revealed aseptic pleocytosis. Five days after the completion of treatment, the symptoms remitted and a new control SPET 3 weeks later was completely normal. A diagnosis of neurotoxicity secondary to OKT3 administration was established.

Topics: Adult; Aphasia; Brain Abscess; Brain Edema; Cardiomyopathy, Dilated; Cerebral Hemorrhage; Cerebrospinal Fluid; Cerebrovascular Circulation; Confusion; Diagnosis, Differential; Headache; Heart Transplantation; Humans; Immunosuppressive Agents; Leukocytosis; Lymphocyte Activation; Male; Meningoencephalitis; Muromonab-CD3; Postoperative Complications; Radiopharmaceuticals; T-Lymphocytes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Serial brain SPECT imaging was performed on patients after subarachnoid hemorrhage and surgical clipping of intracranial aneurysms. A total of 20 HMPAO scans were performed on 9 patients in whom clinical vasospasm did not develop. Areas of diminished regional cerebral blood flow (rCBF) were found near the operative site in 17 of 20 studies, which did not correlate with the patients' neurologic condition and were suggestive of postoperative edema. Brain SPECT imaging has a potentially valuable role to play in the evaluation of postoperative patients susceptible to vasospasm; however, it is important to be aware of postoperative changes in rCBF that are not related to vasospasm.

Topics: Brain; Brain Edema; Cerebrovascular Circulation; Female; Humans; Intracranial Aneurysm; Ischemic Attack, Transient; Male; Middle Aged; Organotechnetium Compounds; Oximes; Postoperative Complications; Subarachnoid Hemorrhage; Technetium Tc 99m Exametazime; Time Factors; Tomography, Emission-Computed, Single-Photon

Topics: Acute Disease; Adult; Blood Flow Velocity; Brain Edema; Cerebral Arteries; Cerebral Infarction; Cerebrovascular Circulation; Cysteine; Humans; Ischemic Attack, Transient; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Xenon

Two cases of organophosphate poisoning are presented along with Tc-99m HMPAO brain SPECT findings in the acute and delayed phases. Perfusion defects were more prominent at the onset of poisoning in both cases.

Topics: Adult; Brain; Brain Edema; Female; Humans; Insecticides; Male; Organophosphorus Compounds; Organotechnetium Compounds; Oximes; Psychoses, Substance-Induced; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Traumatic intracerebral haematomas are a common neurosurgical emergency. Their management, particularly the role of surgical removal, is controversial. Deterioration often occurs late, and is unpredictable. Eight patients with traumatic intracerebral haematomas were admitted to the neurosurgical unit to monitor their clinical state. All were studied within 48 hours of admission with single photon emission computerised tomography (SPECT), using the recently introduced radionuclide 99Technetiumm-Hexamethyl propylene amine oxime (99Tcm-HMPAO). At the time of the SPECT study, all the patients had been clinically stable. Three patients remained so; in the other five, the conscious level deteriorated, necessitating craniotomy and evacuation of the haematoma. In all the patients, the SPECT studies demonstrated perfusion defects that corresponded to the location of the haematoma, as demonstrated by computerised tomography (CT). However, in the five patients who subsequently deteriorated, the perfusion defects seen on the SPECT scan appeared larger than the haematoma, as seen on the CT scan. In addition, there was widespread poor retention of 99Tcm-HMPAO in the ipsilateral hemisphere. These differences were quantifiable. Interestingly, these differences were present at a time when the patients were clinically stable, before their deterioration. It is concluded that SPECT studies with 99Tcm-HMPAO are of possible use as predictors of late deterioration in the management of traumatic intracerebral haematomas.

Topics: Adolescent; Adult; Aged; Brain Edema; Brain Injuries; Cerebral Hemorrhage; Craniotomy; Follow-Up Studies; Frontal Lobe; Hematoma; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Postoperative Complications; Radionuclide Imaging; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, X-Ray Computed