Perfusion Brain Scintigraphy in Central Nervous System Disorders // Перфузионна мозъчна сцинтиграфия при някои заболявания на централната нервна система

Abstract

Настоящата работа въвежда в клиничната практика у нас и разглежда приложението на един от най-съвременните методи - томографската мозъчна сцинтиграфия с Тс-99Мm-НМРАО SРЕСТ при мозъчно-съдовата болест, болестта на Алцхаймер, съдовата деменция и епилепсията. Използван е нов метод с физическо натоварване за оценка на вазодилаторния резерв на мозъчните съдове при хипертоници като рисков фактор за развитие на мозъчно-съдова болест и деменция. Установят се взаимните връзки между перфузионните индекси и нарушенията на мозъчната електрична активност при болни с мозъчен инфаркт. Доказва се диагностичната стойност на невроактивиращите тестове и перфузионната мозъчна сцинтиграфия за ранната диагноза на болестта на Алцхаймер и за диференциалната диагноза между болестта на Алцхаймер и съдовата деменция. Оценяват се възможностите на метода за проследяване ефекта от лечението на пациенти с епилепсия.

The present study is aimed at exploring the application of Tc-99m-HMPAO SPECT perfusion brain scintigraphy for the early diagnosis, differential diagnosis, prognosis and follow-up of cerebral vascular disease Alzheimer’s disease, vascular dementia, and epilepsy. For a period of seven years (1996-2003) the Department of nuclear medicine at St. Marina University Hospital - Varna used Tc-99m-HMPAO SPECT to investigate a total of 187 patients of whom 105 male, 82 female, mean age 48.82 ± 11.65 years. Their distribution according to the clinical diagnosis was as follows: 42 patients with hypertension, 83 patients with brain infarction, 32 with Alzheimer’s disease, 10 with vascular dementia and 20 with epilepsy. Tc-99m-HMPAO SPECT was performed on a gama-camera DIACAM after injecting 20 mCi Tc-99m-HMPAO SPECT at rest or under stress. The stress studies included stimulation with physical exercise, stimulation with acetazolamide (Diamox), a combination of stimulation with physical exercise and acetazolamide, neuroactivation tests, finger - thumb opposition test, labyrinth test. The 64 scintigraphic images were processed by means of a standard SPECT programme and visual assessment of the distribution and radionuclide uptake on the transversals, the sagittal and coronal slides. In the different groups of patients we introduced various semi-quantitative indicators. Tc-99m-HMPAO SPECT performed under conditions of physical exercise is a reliable method for assessment of the autoregulatory mechanisms of the brain vessels in patients with uncomplicated hypertension and detects the structural and functional haemodynamic changes in the resistant brain vessels. The correlation between the regional blood flow and the changes in the thrombocyte aggregation in patients with hypertension of Ilnd degree (r= + 47, p< 0.05) showed a possible connection between the changes in the perfusion indices from the SPECT and the hemorheological changes under conditions of physical exercise. The established positive correlation in the perfusion indices differences obtained by the method of physical exercise and after drug vasodilatation with acetazolamide suggests that the two methods reflect the state and disorders of the autoregulatory capacity of the brain vessels in a similar way. After the introduction of the acetazolamide, Tc-99m-HMPAO SPECT allows for the assessment of the vasodilatory capacity of the cerebellar hemispheres in patients with cross cerebellar diaschisis. Seven and two hours after the beginning of the acute cerebrovascular episodes hypo- and aperfusional changes in the scintigraphic imaging with focal and diffuse character correlated to a large extent with the moderate focal diffusion disorders of the electrical brain activity (r = 0.86) and differed significantly from those in the control group. The presence of a neurovascular connection in the affected hemisphere can be suggestive of a good prognosis after ischaemic stroke. Tc-99m-HMPAO SPECT and the neuroactivation test (finger - thumb opposition test) can be a useful tool for the prognosis of the motor function recovery in these patients. The combination of Tc-99m-HMPAO SPECT and neuroactivation resulted in increased method sensitivity by 6.4% and increased specificity by 17% for the differential diagnosis of patients with Alzheimer’s disease and vascular dementia of the same degree of dementia severity. A very good correlation was established (r= 0.72) in patients with increased perfusion (7 - 10%) in the epileptic focus and a moderate correlation (r= 0.48) was established in patients with a less prominent and unaltered perfusion in the epileptic focus which suggests that Tc-99m-HMPAO SPECT is a reliable method for the assessment of the treatment and prognosis of the frequency and intensity of the seizures in patients with epilepsy.