The Study Of SPECT Cerebral Blood Flow Perfusion Imaging Methods And Its Application In The Assessments Of Brain Dysfunctions In Hyperthyroidism Patients

Objectives:To study the normal distribution patterns of ⁹⁹Tc^m-ECD in adult brain, analyze the SPECT image interpretaiton methods and the value of dipyridamole stress test in cerebrovascular diseases.The changes of regional cerebral blood flow(rCBF) in hyperthyroidism patients and its relations with mood disorders,cognition deficits and other hyperthyroidism related factors were intensely studied.Methods:1.SPECT cerebral blood flow perfusion imaging methodsTotal 169 SPECT scans were performed for 130 individuals.The images were acquired with Elscint Apex Sp-6 or Marconi Irix triple head SPECT 30mins after ⁹⁹Tc^m-ECD injection intravenously.The normal brain distribution patters of ⁹⁹Tc^m-ECD in 34 healthy volunteers(males2,females 14;mean age 35.03±11.81ys) were analyzed visually and semiquantitatively.Another 28 healthy volunteers(males 8,females 20;mean age 35.8±9.41ys) performed rest cerebral blood flow perfusion iamging.Brain anatomic and functional areas were extracted automatically with Brain search 1.10 software.Its accuracy was compared with ROI semiquantitive analysis.The method of SPM analysis for SPECT perfusion images was introduced.Eighteen systemic lupus erythematosus(SLE) patients(males 1,females 17;mean age 34±10.5ys) and 11 healthy controls (males 3,females 8;mean age 28.0±9.7ys) performed rest cerebral blood flow perfusion imaging,the results were analyzed and compared with CT scans.Twenty-four patients with cerebrovascutar diseases(males 13,females 11:mean age 60.0±13.2ys)and 8 male healthy controls(mean age 32.0±12.9ys) performed both rest cerebral blood flow perfusion imaging and dipyridamole stress test.The results were analyzed visually and semiquantitatively.2.SPECT rCBF imaging for brain dysfunctions in hypertyroidism patients SPECT cerebral blood flow perfusion imaging Thirty-seven hyperthyroidism patients(males 10,females 27;mean age 39.27±10.58 ys) were enrolled.The patients were divided into two subgroups:short duration group with duration equal or less than 6 months(n=15),long duration group with duration more than 6 months(n=22).Twenty-eight healthy volunteers matched for age,gender,education and marital with patients were included as controls.SPECT cerebral blood flow perfusion imaging was performed at rest after ⁹⁹Tc^m-ECD injection for all patients and controls.Statistical parametric mapping(SPM2)2.0 was used to investigate the differences of regional cerebral blood flow(rCBF) between different groups.The functional areas were extracted automatically with Brain search 1.10 software.The correlations between rCBF and age,gender,education,marrital state,thyroid hormones, autoimmune antibodies,disease duration were done for patients to explore the relationship of these factors.In 7 patients,rCBF changes were followed up 5month to lyear after euthyroid.Personality traits analysis The personality traits of 35 patients and 28 controls were assessed with EPQ questionnaire.The personality traits were assessed again for 7 patients 5month to lyear after euthyroid.The correlation analyses were done between EPQ scores,rCBF,thyroid hormones and autoimmune antibodies.Mood disorders assessment The mood disorders of.37 patients and 28 controls were assessed with SDS rating scales for depression,SAS rating scales for anxiety.Mood changes were followed up for 7 patients 5month to lyear after euthyroid.The factors related to depression and anxiety were analyzed by one-way variance analysis and mutiple stepwise regression analysis.Cognition functions assessment Number cancellation test(NCT) Was performed for attention,Wechsler Memory Scales(WMS) was performed for memory assessment for all 37 patients and 28 healthy controls.Cognition changes were followed up for 7 patients 5month to lyear after euthyroid. The factors related to attention and memory were analyzed by one-way variance analysis and mutiple stepwise regression analysis.Results:1.SPECT cerebral blood flow perfusion imaging methods⁹⁹Tc^m-ECD distributed unevenly at different site of normal brain.The results of semiquantitive and visual analysis had high correlation (r=0.756,P＜0.05).The brain functional areas extractd automatically was as the same as those analyzed visual]y.The uptake of ⁹⁹Tc^m-ECD in the same regions were similar to those by semiquantitatively before.The sensitivity of rest rCBF imaging for detecting SLE brain involvement was 67.7%by visual analysis,and 70%by semiquantitative analysis.The sensitivity of SPECT imaging was 80%for patients with obvious headache or vomit,however it was only 20%for CT scan.Cingulate gyrus and temporal-parietal region were the most involved regions.The sensitivity was improved from 58.3%to 83.3%after dipyridamole stress test for cerebrovascular diseases.Four different patterns of cerebrovascular reaction could be found with dipyridamole stress test.2.SPECT rCBF imaging for brain dysfunctions in hypertyroidism patients SPECT rCBF imaging for hyperthyroidism patients rCBF in limb system and frontal lobe,including hippocampus,parahippocampal gyrus,anterior cingulate,entorhinal cortex,subgenual,amygadala,caudate and superior frontal gyrus,middle frontal gyrus,inferior frontal gyrus,medial frontal gyrus were decreased significantly in SPM analysis.Culmen region of cerebellum and brain stem were also involved(FWE correction,P＜0.05).There was no significant difference between rCBF of short duration group and long duration group,but the involved areas of long duration group were slightly larger than those of short duration group when compared to control group,rCBF was improved significantly for 7 patients after euthyroid(FWE correction,p＜0.05).rCBF in left superior frontal gyrus were correlated negatively with age,positively with right rectal gyrus and parahippocampal gyrus(p＜0.05).rCBF in uncus,left lingual gyrus,post cingulate,left occipital gyrus,left vision associated cortex and subcallosal gyrus were correlated negatively with FT3(p＜0.05) and which in left uncus,left lingual gyrus,left occipital gyrus,left vision associated cortex,posterior cingulate,caudate nucleus and subgenual were correlated negatively with FT4(p＜0.05).rCBF in middle occiptal gyrus was correlated negatively with sTSH(p＜0.05).There were no significant correlations between rCBF and TgAb,TRAb,TPOAb.Personality traits analysis Hyperthyroidism patients had much more neuroticism and psychoticism characteristics compared with controls,which had not changed significantly after euthyroid.There were no correlations between personality traits and thyroid hormones, autoimmune antibodies.The scores of neuroticism were correlated negatively with rCBF in thalamus,parahippocampal gyrus,posterior entorhinal cortex,globus pallidus and mammilary body(p＜0.05).Mood disorders assessment Compared to healthy controls,patients had slight to moderate depression and anxiety(p＜0.05).There were no significant difference between short and long duraton group(p＞0.05).The depression mood was improved significantly after euthyroid (p＜0.05).However,the improvement was less significant for anxiety after euthyroid(p＞0.05).There were no significant correlations between depression,anxiety and age,gender,marrital,education,duration,thyroid hormones,autoimmune antibodies for both patients and controls(p＞0.05).rCBF in limb system,thalamus,basal ganglia were correlated negatively with depression,and which in right talamus was correlated negatively with anxiety(p＜0.05).The personality traits of introversion and unstable mood,also decreased rCBF in subcallosal gyrus were independent factors for depression and the unstable mood was independent factor for anxiety in hyperthyroidism patients(p＜0.05). Cognition functions assessment Patients with long duration had significant memory deficits(p＜0.05),no memory deficits were found for short duration patients.No attention deficits were found in both patients and controls(p＞0.05).rCBF in right temporal,right caudate,right auditory associated cortex,age and duration were independent factors for attention of patients(p＜0.05).rCBF in right halamus,right amygdala,age and attention,FT4 were independent factors for memory of patients(p＜0.05).There were no significant correlations between attention,memory and depression,anxiety,FT3,sTSH and autoimmune antibodies(p＞0.05).Conclusion:SPECT rCBF imaging is sensitive in detecting ischemic cerebrovascular diseases,dipyridamole stress test can improve the sensitivity further and can reflect the cerebraovascular reaction.Brain functional areas extraction is an accurate and convient method,and SPM analysis is a sensitive and objective method for image interpretation. SPECT rCBF imaging is valuable for hyperthyroidism brain function assessment.Hypoperfusion in limb system,frontal lobe,cerebellar and brain stemare shown for hyperthyroidism patients,which might be related to elevated concentrations of thyroid hormones.Impaired rCBF might be decreased after euthyroid.Hyperthyroidism patients have obvious depression and anxiety,which might be associated with special personality traits and rCBF impariment.Memory deficits are significant for longer duration patients,which might be accompanied by rCBF in thalamus and amygdala.No attention deficits are found for hyperthyroidism patients.