technetium-tc-99m-exametazime and Coma

Topics: Brain; Brain Death; Cerebral Angiography; Cerebrovascular Circulation; Coma; Death; Humans; Intensive Care Units; Nuclear Medicine Department, Hospital; Pentetic Acid; Radiopharmaceuticals; Software Design; Spain; Technetium Tc 99m Exametazime; Tissue and Organ Harvesting; Tissue Distribution; Tissue Donors; Tomography, Emission-Computed, Single-Photon

Four hours after having taken 10 ecstasy tablets a Grand Mal seizure occurred in a 19-year-old woman followed by coma, hyperthermia, tachycardia, tachypnea, and renal failure. After awakening she was oriented but presented with helplessness, disconcertion, hallucinations, panic attacks, and amnesic syndrome. Computed tomography and magnetic resonance imaging scans of the brain were normal. [99Tc]-hexamethylpropyleneamine oxime (HMPAO)-single photon emission computed tomography (SPECT), 20 days after intoxication, showed reduced, inhomogeneous, supratentorial tracer uptake bilaterally. Electroencephalography (EEG) disclosed diffuse slowing and occasionally generalized sharp waves. Valproic acid was begun. Except for slight amnesia, neuropsychological deficits had disappeared and [99Tc]-HMPAO-SPECT normalized, 29 days later. Decreased cortical blood flow was explained by vasoconstriction following ecstasy-induced depletion of serotonin.

Topics: Adult; Brain Ischemia; Cerebral Cortex; Coma; Dominance, Cerebral; Drug Overdose; Electroencephalography; Epilepsy, Tonic-Clonic; Female; Follow-Up Studies; Humans; N-Methyl-3,4-methylenedioxyamphetamine; Neuropsychological Tests; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vasoconstriction

In this study we submitted 24 comatose patients (Glasgow Coma Score <8) to Single Photon Emission Tomography (SPECT) during the clinical course of coma to verify its utility and the relationship between SPECT and CT scan data. SPECT was recorded following i.v. injection of Xe-133 in 17 patients and of Tc-99m-HMPAO or Tc-99m-ECD in the remaining 7. SPECT data recorded during the acute phase of coma did not show a clear correlation between cerebral blood flow (CBF) and outcome. SPECT and CT scan detected abnormalities in the same areas in 6 cases (25%); 6 patients (25%) with focal CT-scan lesions showed no focal CBF alterations in the same regions; conversely, in the remaining 12 cases (50%) SPECT disclosed severe perfusion abnormalities where no lesions were detectable on CT-scan. SPECT allowed us to recognize different regional flow patterns, such as absolute or relative hyperemia or oligoemia, which could not be checked with other means, thus improving patient's management. Apart from cerebral ischemia, there was no relationship between lesions on CT-scan and flow pattern. Our preliminary results suggest that SPECT can improve both the knowledge of patient's neurological conditions and management in comparison to the use of only CT scan.

Topics: Adolescent; Adult; Aged; Brain; Cerebrovascular Circulation; Coma; Cysteine; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Persistent Vegetative State; Pilot Projects; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Treatment Outcome; Xenon Radioisotopes

Diagnosis of brain death must be certain to allow discontinuation of artificial ventilation and organ transplantation. Brain death is present when all functions of the brain stem have irreversibly ceased. Clinical and electrophysiological criteria may be misinterpreted due to drug intoxication, hypothermia or technical artefacts. Thus, if clinical assessment is suboptimal, reliable early confirmatory tests may be required for demonstrating absence of intracranial blood flow. We have easily carried out and interpreted 99mTc HM-PAO SPECT in a consecutive series of 40 comatose patients with brain damage, without discontinuing therapy. Brain death was diagnosed in 7 patients, by recognising absence of brain perfusion, as shown by no intracranial radionuclide uptake. In patients in whom perfusion was seen on brain scans, HM-PAO SPECT improved assessment of the extent of injury, which in general was larger than suggested by CT.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Brain; Brain Damage, Chronic; Brain Death; Child; Coma; Female; Humans; Life Support Care; Male; Middle Aged; Organotechnetium Compounds; Oximes; Prognosis; Regional Blood Flow; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A total of 24 patients with clinical evidence of brain death (n = 17), severe coma (n = 2; GCS approximately 3) and apallic syndrome (n = 4) underwent a comparative investigation with 99mTc-HMPAO brain scintigraphy, EEG, auditory and somatosensory evoked potentials. Accompanied by EEG and evoked potentials, brain scintigraphy enabled confirmation of cerebral death in 15/17 patients. In one case clinical examination and evoked potentials suggest brain death, but cerebral perfusion and EEG were normal ("brain stem death"). One patient with evidence of cerebral death in clinical examination, brain scintigraphy and evoked potentials, showed questionable focal EEG activity; however, autopsy revealed intravital autolysis of the entire brain. All patients with apallic syndrome and deep coma showed a distinct cerebral perfusion, but gross EEG abnormalities; evoked potentials were delayed or absent. Planar scintigraphy with 99mTc-HMPAO appears to be superior to neurophysiological techniques discriminating patients with agonal cerebral dysfunction from those with brain death.

Topics: Adolescent; Adult; Aged; Blood-Brain Barrier; Brain Death; Cerebrovascular Circulation; Coma; Diagnosis, Differential; Electroencephalography; Evaluation Studies as Topic; Evoked Potentials, Auditory, Brain Stem; Evoked Potentials, Somatosensory; Female; Humans; Male; Middle Aged; Neurologic Examination; Organotechnetium Compounds; Oximes; Radionuclide Imaging; Sensitivity and Specificity; Technetium Tc 99m Exametazime

Management of patients presenting with traumatic persistent vegetative state (PVS) calls for extensive resources. The ability to predict whether or not a patient is likely to recover is a critical issue. In 12 patients with PVS admitted consecutively for early rehabilitation after head injury, pattern of brain activity was measured by 99mTc-hexamethyl-propylenamineoxime (99mTc-HM-PAO) brain SPECT (single photon emission computer tomography). All patients were re-investigated after a mean observation period of 3 years. A global reduction of cortical blood flow was a reliable predictor of poor long-term outcome, but the demonstration of only focal deficits did not reliably indicate a favourable outcome. Brain SPECT may help to improve outcome prediction in patients with traumatic PVS.

Topics: Adolescent; Adult; Coma; Craniocerebral Trauma; Female; Follow-Up Studies; Glasgow Coma Scale; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Predictive Value of Tests; Prognosis; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Technetium-99m hexamethylpropyleneamine oxime (Tc-99m HM-PAO) was successfully used with single photon emission computed tomography (SPECT) on fourteen comatose patients who had acute head injuries. The SPECT scans were correlated with computed tomography (CT) scans obtained within 24 hours of the injury. Tc-99m HM-PAO SPECT was shown to have the following advantages: It reflected perfusion changes, was more sensitive than CT in demonstrating more lesions, and demonstrated lesions at an earlier stage than those demonstrated with CT. Different types of lesions, as evidenced by cerebral perfusion changes, have been described and categorized. The lesions that had a favorable prognosis could be separated from those with an unfavorable prognosis on the basis of the findings of Tc-99m HM-PAO SPECT.

Topics: Accidental Falls; Accidents, Traffic; Acute Disease; Adolescent; Adult; Brain; Cerebrovascular Circulation; Coma; Craniocerebral Trauma; Humans; Male; Organometallic Compounds; Oximes; Prognosis; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed; Tomography, X-Ray Computed