| ObjectiveWith the development of living standard, internet has incredibly expanded across the world over the last few years. However, maladaptive use of the internet has leaded to internet addiction disorder (IAD).There is still no widely accepted standard for diagnose of IAD. The medical imaging study focused on IAD is rare. In this study, we investigated the changes of regional cerebral blood flow (rCBF) in patients with IAD using99Tcm-ethylcysteinate dimer (ECD) SPECT. The imagings were analyzed using three methods, including visual analysis, region of interest (ROD and statistical parametric mapping (SPM). The purpose of the study is to get objective diagnostic evidence for patients with IAD and to help the proper treatment selection.MethodsThe cerebral blood perfusion SPECT imaging of12healthy volunteers and35patients with IAD were retrospectively analyzed. Each person underwent rest and adenosine stress SPECT CBF perfusion imaging with two-day protocol using a three-detector SPECT with low-energy collimator. The rCBF change of patients with IAD was analyzed using visual analysis and two semi-quantitative analyses, such as ROI with cerebral template and SPM. In each study a weight-appropriate dose of99Tcm-ECD was administered intravenously. Adenosine (0.8mg/kg) was given intravenously at3minutes before the injection of99Tcm-ECD, which should be finished within6minutes.According to cerebral structure and SPECT imaging,22encephalic regions were observed, which consisted of bilateral superior frontal gyrus, middle frontal gyms, inferior frontal gyrus, postcentral gyrus, superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus, cingulate gyrus, precuneus, occipital lobe and thalamus. Based on our criterion, encephalic region with no abnormal distribution of radioactivity was considered normal, while others that expressed sparse or defect in continuous two or more transects were treated as abnormal. Three transects were selected on the basis of ROI method. And the symmetrical ROIs of bilateral cerebellum in the first transect were drawn, which were close to the bottom of whole brain. Temporal lobe, basal ganglia and thalamus could be clearly showed in the second transect, which were near the middle part of brain. The third transect, which approached the top part of brain, could display the frontal and parietal lobes unequivocally. The bilateral superior frontal gyrus, middle frontal gyrus, inferior frontal gyrus, postcentral gyrus, superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus, cingulate gyrus, precuneus, occipital lobe and thalamus were automatically drawn through the standard template in the second and third transects. Following that, we appropriately adjusted ROIs to make more accurate results. We defined ROI with radioactive counts from0.9to1.1as normal, and radioactive counts <0.9or>1.1as abnormal. We took average radioactive counts of bilateral cerebellum as reference, and regarded the ratio of each ROI and the reference as final evaluating indicator. SPM method was operated in MATLAB R2009b. SPM8was chosen to analyze rCBF of patient with IAD after imaging conversion, normalization, smooth, statistics and result display.Firstly,12healthy volunteers and35patients with IAD underwent SPECT CBF perfusion imaging at rest state to distinguish the difference between the two groups. Visual analysis, ROI and SPM were applied to judge whether rCBF of patients with IAD increased or decreased. Data were analyzed by two-sample t-test,P<0.01.Secondly, the two groups underwent SPECT CBF perfusion imaging at both the rest state and adenosine stress state, respectively. Visual analysis, ROI and SPM were utilized to assess the rCBF of healthy donors and patients with IAD. Data were analyzed by paired t-test,P<0.01.Finally, SPECT CBF perfusion imaging was performed in volunteers and patients with IAD at the adenosine stress state. The visual analysis, ROI method and SPM method were applied to evaluate change of rCBF in patients with IAD. Data were analyzed by two-sample t-test,P<0.01.ResultsPart one1. Visual analysisIn the healthy group, there were total132pairs of normal encephalic regions. Three hundred and eighty five pairs of encephalic regions were obtained in patients with IAD, which consisted of287pairs of normal regions and98pairs of abnormal regions. Abnormal encephalic regions consisted of1pair of superior frontal gyrus,9pairs of middle frontal gyrus,8pairs of inferior frontal gyrus,6pairs of cingulate gyrus,15pairs of superior temporal gyrus,8pairs of middle temporal gyrus,12pairs of inferior temporal gyrus,8pairs of postcentral,7pairs of precuneus,8pairs of occipital lobe and16pairs of thalamus.2. ROI methodIn patients with IAD, rCBF increased in right middle frontal gyrus. Other encephalic regions, such as left middle frontal gyrus and bilateral superior frontal gyrus, inferior frontal gyrus, postcentral gyrus, superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus, cingulate gyrus, precuneus, thalamus and occipital lobe, didn’t show increasing rCBF. Moreover, no decreasing rCBF in encephalic regions was shown by ROI method.3. SPM methodIn patients with IAD, rCBF was found higher in these encephalic regions, including right middle frontal gyrus and left angular gyrus. Relative to rCBF increasing, rCBF was found lower in left paracentral lobule. Furthermore, there was no difference observed in other encephalic regions between healthy donors and patients with IAD.Part two1. rCBF difference in volunteers between the rest and adenosine stress state1.1Visual analysisThere were132pairs of normal encephalic regions separately at the rest and adenosine stress state.1.2ROI methodCompared with the rest state, rCBF increased in bilateral middle temporal gyrus, left inferior temporal gyrus, left precuneus, right occipital and right thalamus at adenosine stress state. However, decreasing rCBF wasn’t recognized by this method.1.3SPM methodrCBF at the adenosine stress state were higher in bilateral inferior frontal gyrus, right precentral gyrus, right superior temporal gyrus, left middle temporal gyrus, right inferior temporal gyrus, right cingulate, left cuneate lobe and left lingual gyrus than at the resting state. And rCBF were lower in bilateral superior frontal gyrus, bilateral middle frontal gyrus, right inferior frontal gyrus, right precentral gyrus, bilateral postcentral gyrus, right inferior parietal lobule, left uncus of limbic lobe and right middle occipital gyrus at adenosine stress state.2. rCBF difference in patients with IAD between the rest and adenosine stress state2.1Visual analysis For patients with IAD, there were385pairs of encephalic regions obtained at both state, respectively, which included287pairs of normal ones and98pairs of abnormal ones at rest state, and299pairs of normal ones and86pairs of abnormal ones at adenosine stress state. At rest state,1pair of superior frontal gyrus,9pairs of middle frontal gyrus,8pairs of inferior frontal gyrus,6pairs of cingulate gyrus,15pairs of superior temporal gyrus,8pairs of middle temporal gyrus,12pairs of inferior temporal gyrus,8pairs of postcentral,7pairs of precuneus,8pairs of occipital lobe and16pairs of thalamus were included in the abnormal encephalic regions. Meanwhile at adenosine stress state,8pairs of superior frontal gyrus,8pairs of middle frontal gyrus,6pairs of inferior frontal gyrus,7pairs of cingulate gyrus,6pairs of postcentral,8pairs of precuneus,7pairs of superior temporal gyrus,8pairs of middle temporal gyrus,10pairs of inferior temporal gyrus,10pairs of occipital lobe and8pairs of thalamus were contained in the abnormal encephalic regions.2.2ROI methodrCBF increased in bilateral superior temporal gyrus, left middle temporal gyrus and right occipital lobe at adenosine stress state comparing with rest state. But decreasing rCBF wasn’t recognized by this method.2.3SPM methodrCBF were higer in bilateral middle frontal gyrus, bilateral inferior frontal gyrus, right paracentral lobule, left superior temporal gyrus, right middle temporal gyrus, left inferior temporal gyrus, left uncus of limbic lobe, right parahippocampal gyrus, left cingulate gyrus, right lingual gyrus, right putamen and left insula with patients with IAD at adenosine stress state. And at adenosine stress state, rCBF were lower in left superior frontal gyrus, bilateral middle frontal gyrus, left inferior frontal gyrus, left precentral gyrus, left superior temporal gyrus, right inferior temporal gyrus, right transverse temporal gyrus, left inferior parietal lobule, left postcentral gyrus, left precuneus and right inferior occipital gyrus.Part three1. Visual analysisFor the volunteers, there were total132pairs of normal encephalic regions. We obtained385pairs of encephalic regions from patients with IAD, which consisted of299pairs of normal ones and86pairs of abnormal ones at adenosine stress state. Abnormal encephalic regions included8pairs of superior frontal gyrus,8pairs of middle frontal gyrus,6pairs of inferior frontal gyrus,7pairs of cingulate gyrus,6 pairs of postcentral,8pairs of precuneus,7pairs of superior temporal gyrus,8pairs of middle temporal gyrus,10pairs of inferior temporal gyrus,10pairs of occipital lobe and8pairs of thalamus.2. ROI methodThere was no contradistinction detected by rCBF between patients with IAD and volunteers in this method.3. SPM methodCompared with volunteers, rCBF increased in right middle frontal gyrus, right inferior frontal gyrus, right postcentral gyrus, left superior temporal gyrus and left cingulate gyrus in patients with IAD at adenosine stress state. In addition, rCBF deceased in left inferior parietal lobule and left precuneus at adenosine stress state. There was no significant difference displayed between two groups in any other encephalic regions by SPM method.ConclusionsThe SPECT CBF perfusion imaging rCBF in patient with IAD showed abnormal in frontal gyrus, limbic lobe and temporal gyrus. It is an effective imaging evidence for the brain reward system.By using adenosine stress CBF imaging, some of abnormal encephalic regions were found which couldn’t be shown in the rest brain imaging. However, there had some false-negative cases between the volunteers and the patients with IAD by comparing their adenosine stress CBF imaging individuallySPM method is a useful tool for analyzing the changes in encephalic regions. Compared with traditional ROI method, SPM method is more accurate in finding potential abnormal encephalic regions, and it could more informatively locate abnormal encephalic regions. However, ROI method could analyze image of single patient while SPM method could not. The two methods would effectively supplement each other. |
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