Pinchen Yang

Neuronal Specificity of Acupuncture Response: A fMRI Study with Electroacupuncture

Recently, neuronal correlates of acupuncture stimulation in human brain have been investigated by functional neuroimaging. The preliminary findings suggest that acupuncture at analgesic points involves the pain-related neuromatrix and may have acupoint-brain correlation. Although multiple models of control stimulations have been applied to address the specificity of the needling effect clinically, their impacts have not been evaluated by functional neuroimaging. With the advantage of objective parameter setting, electroacupuncture (EA) was used in this study to devise three distinct controls for real EA, i.e., mock EA (no stimulation), minimal EA (superficial and light stimulation), and sham EA (same stimulation as real EA) applied at nonmeridian points. Fifteen healthy volunteers received real EA at analgesic point Gallbladder 34 (Yanglinquan), sham EA, and one of either mock EA or minimal EA over the left leg in counter-balanced orders. Multisubject analysis showed that sham EA and real EA both activated the reported distributed pain neuromatrix. However, real EA elicited significantly higher activation than sham EA over the hypothalamus and primary somatosensory-motor cortex and deactivation over the rostral segment of anterior cingulate cortex. In the comparison of minimal EA versus mock EA, minimal EA elicited significantly higher activation over the medial occipital cortex. Single-subject analysis showed that superior temporal gyrus (encompassing the auditory cortex) and medial occipital cortex (encompassing the visual cortex) frequently respond to minimal EA, sham EA, or real EA. We concluded that the hypothalamus-limbic system was significantly modulated by EA at acupoints rather than at nonmeridian points, while visual and auditory cortical activation was not a specific effect of treatment-relevant acupoints and required further investigation of the underlying neurophysiological mechanisms.

Sequential Changes of Myocardial Microstructure in Patients Postmyocardial Infarction by Diffusion-Tensor Cardiac Mr Correlation with Left Ventricular Structure and Function

Background—We used diffusion-tensor cardiac MR to investigate myocardial microstructure changes, including tissue integrity (mean diffusivity [MD], fractional anisotropy) and fiber architecture (helix angles) in patients with recent myocardial infarction (MI). This study aimed to investigate the sequential changes of myocardial microstructure and its relationships with changes of macrostructure and function of the left ventricle post-MI. Methods and Results—Seventeen patients (age, 55.1±11.5 years; all men) participated in the follow-up study. Diffusion-tensor cardiac MR, cine gradient echo for left ventricle function, and late gadolinium enhancement for viability were measured from recent to chronic MI (median interval, 191 days). When compared with the remote zone, the infarct-adjacent zone showed overall increase of MD (2-way MANOVA, F1,16=36.3; P<0.001), decrease of fractional anisotropy (F1,16=5.8; P=0.029), and decrease of mean helix angles (F1,16=62.0; P<0.001). From recent to chronic MI, there was overall sequential decrease of MD (F1,16=22.6; P<0.001) and increase of fractional anisotropy (F1,16=7.8; P=0.013). Multiple linear regression showed that the improvement of wall thickening in the infarct-adjacent zone correlated with sequential decrease of MD in the infarct-adjacent zone (r=−0.70; P=0.002) and increase of mean helix angles (ie, more right-handed helical myofiber reorientation, predominantly subendocardial location) in the remote zone (r=0.60; P=0.011). Likewise, wall thickening in the remote zone correlated with MD in the remote zone (r=−0.72; P=0.001) and mean helix angles in the infarct-adjacent zone (r=0.72; P=0.001). Conclusion—Diffusion-tensor cardiac MR suggests that sequential zonal improvement of tissue integrity and fiber architecture remodeling both associate with sequential recovery of zonal wall thickening of the left ventricle from recent to chronic MI.

Coronary arterial calcification on low-dose ungated MDCT for lung cancer screening: concordance study with dedicated cardiac CT.

OBJECTIVE Coronary artery calcification (CAC) is frequently detected on low-dose ungated MDCT performed for lung cancer screening. We aimed to determine the concordance of CAC scores on low-dose ungated and regular-dose ECG-gated MDCT. SUBJECTS AND METHODS The subjects were 513 patients consecutively registered for health screening and undergoing both low-dose ungated (120 kVp, 20 mAs) and regular-dose ECG-gated MDCT (120 kVp, 150 mAs, retrospective ECG gating). The first 30 cases were used for protocol optimization and a training session. Agatston score on regular-dose ECG-gated and low-dose ungated MDCT in the other 483 cases (320 men; mean age, 62.2 +/- 13.2 [SD] years) was calculated by two observers in a blinded manner. Interobserver and intertechnique scoring variability and concordance were calculated. RESULTS The mean of interobserver scoring variability for regular-dose ECG-gated MDCT was 3.6% and for low-dose ungated MDCT was 9.6%. Regular-dose ECG-gated MDCT depicted CAC in 221 (46%) of the subjects. With low-dose ungated MDCT, observers 1 and 2, respectively, had five and seven false-positive and five and four false-negative predictions. All the miscategorized scores were 12 or less. The negative predictive values of CAC on low-dose ungated MDCT were 98% and 99% for observers 1 and 2, respectively. For patients with CAC, the mean intertechnique scoring variability was 40-43%. For all 483 subjects, the intertechnique concordance of the four major score ranks (0, 1-100, 101-400, > 400) was high (kappa = 0.89 for the two observers). CONCLUSION Low-dose ungated MDCT with an optimized protocol is reliable for prediction of the presence of CAC and categorization of the four major Agatston score ranks. This technique may be useful for coronary artery disease risk stratification of persons undergoing low-dose ungated MDCT for lung cancer screening.

Intramural Blood Pools Accompanying Aortic Intramural Hematoma: CT Appearance and Natural Course

PURPOSE To evaluate multidetector computed tomographic (CT) images to investigate the prevalence, morphology, natural course, and prognostic effect of intramural blood pools (IBPs) in patients with acute intramural hematoma (IMH). MATERIALS AND METHODS Institutional review board approval and written informed consent were obtained. Sixty-five patients (41 men; mean age, 65.9 years ± 11.3 [standard deviation]) with acute IMH undergoing three or more multidetector CT examinations during follow-up for 12 months or longer (median = 18 months), except for those undergoing surgery (n = 16), were enrolled. Associated factors of developing and resorption of IBP in IMH were analyzed by using logistic regression. RESULTS There were 40 IBPs in 10 patients at initial multidetector CT, and 15 new IBPs developed in 11 patients during follow-up. IBPs occurred most in the descending thoracic (55% [31 of 56]) and abdominal (41% [23 of 56]) aorta in 28% (18 of 65) of patients. During 33.8 months (range, 2.8-50 months) of follow-up in these 18 patients, 57% (32 of 56) of IBPs showed complete resorption in 15 patients, 29% (16 of 56) of IBPs showed incomplete resorption in eight patients, and 14% (eight of 56) of IBPs had interrupted follow-up because of surgery or death in three patients. Logistic regression showed that age younger than 70 years (odds ratio [OR], 8.74; 95% confidence interval [CI]: 1.03, 76.9) and IMH wall thickness greater than 10 mm (OR, 4.93; 95% CI: 1.04, 23.0) were associated with developing IBP at initial multidetector CT, while IBP with larger transmural diameter (OR, 1.16; 95% CI: 1.02, 1.31) and multidetector CT-demonstrated connection with intercostal or lumbar artery (63% [35 of 56]) (OR, 5.44; 95% CI: 1.43, 20.9) were associated with incomplete resorption. CONCLUSION IBPs are frequently observed at multidetector CT in patients with IMH. They may resolve over time or appear during follow-up. These findings are not associated with a poor prognosis, and IBPs should be distinguished from ulcerlike projections.

Effects of interpolation methods in spatial normalization of diffusion tensor imaging data on group comparison of fractional anisotropy

This study investigated the effects on the measurement of fractional anisotropy (FA) during interpolation of diffusion tensor images in spatial normalization, which is required for voxel-based statistics. Diffusion tensor imaging data were obtained from nine male patients with attention deficit/hyperactivity disorder and nine age-matched control subjects. Regions of interest were selected from the genu of corpus callosum (GCC) and the right anterior corona radiata (RACR), with FA values measured before and after spatial normalization using two interpolation algorithms: linear and rotationally linear. Computer simulations were performed to verify the experimental findings. Between-group difference in FA was observed in the GCC and RACR before spatial normalization (P<.00001). Interpolation reduced the measured FA values significantly (P<.00001 for both algorithms) but did not affect the group difference in the GCC. For the RACR, the between-group difference vanished (P=.968) after linear interpolation but was relatively unaffected by using rotationally linear interpolation (P=.00001). FA histogram analysis and computer simulations confirmed these findings. This work suggests that caution should be exercised in voxel-based group comparisons as spatial normalization may affect the FA value in nonnegligible degrees, particularly in brain areas with predominantly crossing fibers.

Absence of gender effect on children with attention-deficit/hyperactivity disorder as assessed by optimized voxel-based morphometry

Brain abnormalities, as determined by structural magnetic resonance imaging (MRI), have been reported in patients with attention-deficit hyperactivity disorder (ADHD); however, female subjects have been underrepresented in previous reports. In this study, we used optimized voxel-based morphometry to compare the total and regional gray matter volumes between groups of 7- to 17-year-old ADHD and healthy children (total 114 subjects). Fifty-seven children with ADHD (n=57, 35 males and 22 females) and healthy children (n=57) received MRI scans. Segmented brain MRI images were normalized into standardized stereotactic space, modulated to allow volumetric analysis, smoothed and compared at the voxel level with statistical parametric mapping. Global volumetric comparisons between groups revealed that the total brain volumes of ADHD children were smaller than those of the control children. As for the regional brain analysis, the brain volumes of ADHD children were found to be bilaterally smaller in the following regions as compared with normal control values: the caudate nucleus and the cerebellum. There were two clusters of regional decrease in the female brain, left posterior cingulum and right precuneus, as compared with the male brain. Brain regions showing the interaction effect of diagnosis and gender were negligible. These results were consistent with the hypothesized dysfunctional systems in ADHD, and they also suggested that neuroanatomical abnormalities in ADHD were not influenced by gender.

Diffusion tensor imaging study of white matter fiber tracts in adolescent attention-deficit/hyperactivity disorder

A diffusion tensor imaging (DTI) study was conducted in 12 adolescents with attention deficit/hyperactivity disorder and 14 age- and IQ-matched healthy controls. Inter-subject comparison of fractional anisotropy (FA) of the whole brain between the groups was obtained using the tract-based spatial statistics method. Results revealed significantly lower FA in widespread white matter tracts in cases relative to controls. Also, the FA measure of identified regions was associated with cognitive performance.

Short-TE proton magnetic resonance spectroscopy investigation in adolescents with attention-deficit hyperactivity disorder

In this study, short echo time (1)H-magnetic resonance spectroscopy (MRS) was applied for quantification of neurometabolites using the LC Model algorithm in Taiwanese adolescents with attention-deficit hyperactivity disorder (ADHD). Proton magnetic resonance spectra were acquired bilaterally on the prefrontal area (part of the anterior cingulate gyrus and part of the medial frontal gyrus) in 15 adolescents with ADHD (average age of 13.88years) and 22 controls (average age of 14.85years). Absolute metabolite levels and ratios relative to creatine plus phosphocreatine (Cr+PCr) were obtained to be compared between groups. Results showed that adolescents with ADHD had significantly lower mean right prefrontal levels of Cr+PCr as compared with the controls. No significant differences between groups were noted in the remainder of the prefrontal metabolites. As for the group comparison of relative ratios, the N-acetylaspartate/Cr+PCr ratio was significantly higher in the right prefrontal regions of ADHD adolescents. This finding provides evidence of a right prefrontal neurochemical alteration in ADHD adolescents, which is consistent with current ADHD theory of prefrontal neuropathology with developmental mechanism. In addition, it highlights the importance of the method in interpretation of MRS findings in the context of ADHD.

Sequential Changes of Myocardial Microstructure in Patients Postmyocardial Infarction by Diffusion-Tensor Cardiac MRCLINICAL PERSPECTIVE

Background—We used diffusion-tensor cardiac MR to investigate myocardial microstructure changes, including tissue integrity (mean diffusivity [MD], fractional anisotropy) and fiber architecture (helix angles) in patients with recent myocardial infarction (MI). This study aimed to investigate the sequential changes of myocardial microstructure and its relationships with changes of macrostructure and function of the left ventricle post-MI. Methods and Results—Seventeen patients (age, 55.1±11.5 years; all men) participated in the follow-up study. Diffusion-tensor cardiac MR, cine gradient echo for left ventricle function, and late gadolinium enhancement for viability were measured from recent to chronic MI (median interval, 191 days). When compared with the remote zone, the infarct-adjacent zone showed overall increase of MD (2-way MANOVA, F1,16=36.3; P<0.001), decrease of fractional anisotropy (F1,16=5.8; P=0.029), and decrease of mean helix angles (F1,16=62.0; P<0.001). From recent to chronic MI, there was overall sequential decrease of MD (F1,16=22.6; P<0.001) and increase of fractional anisotropy (F1,16=7.8; P=0.013). Multiple linear regression showed that the improvement of wall thickening in the infarct-adjacent zone correlated with sequential decrease of MD in the infarct-adjacent zone (r=−0.70; P=0.002) and increase of mean helix angles (ie, more right-handed helical myofiber reorientation, predominantly subendocardial location) in the remote zone (r=0.60; P=0.011). Likewise, wall thickening in the remote zone correlated with MD in the remote zone (r=−0.72; P=0.001) and mean helix angles in the infarct-adjacent zone (r=0.72; P=0.001). Conclusion—Diffusion-tensor cardiac MR suggests that sequential zonal improvement of tissue integrity and fiber architecture remodeling both associate with sequential recovery of zonal wall thickening of the left ventricle from recent to chronic MI.

Sequential Changes of Myocardial Microstructure in Patients Postmyocardial Infarction by Diffusion-Tensor Cardiac MRCLINICAL PERSPECTIVE: Correlation With Left Ventricular Structure and Function

Background—We used diffusion-tensor cardiac MR to investigate myocardial microstructure changes, including tissue integrity (mean diffusivity [MD], fractional anisotropy) and fiber architecture (helix angles) in patients with recent myocardial infarction (MI). This study aimed to investigate the sequential changes of myocardial microstructure and its relationships with changes of macrostructure and function of the left ventricle post-MI. Methods and Results—Seventeen patients (age, 55.1±11.5 years; all men) participated in the follow-up study. Diffusion-tensor cardiac MR, cine gradient echo for left ventricle function, and late gadolinium enhancement for viability were measured from recent to chronic MI (median interval, 191 days). When compared with the remote zone, the infarct-adjacent zone showed overall increase of MD (2-way MANOVA, F1,16=36.3; P<0.001), decrease of fractional anisotropy (F1,16=5.8; P=0.029), and decrease of mean helix angles (F1,16=62.0; P<0.001). From recent to chronic MI, there was overall sequential decrease of MD (F1,16=22.6; P<0.001) and increase of fractional anisotropy (F1,16=7.8; P=0.013). Multiple linear regression showed that the improvement of wall thickening in the infarct-adjacent zone correlated with sequential decrease of MD in the infarct-adjacent zone (r=−0.70; P=0.002) and increase of mean helix angles (ie, more right-handed helical myofiber reorientation, predominantly subendocardial location) in the remote zone (r=0.60; P=0.011). Likewise, wall thickening in the remote zone correlated with MD in the remote zone (r=−0.72; P=0.001) and mean helix angles in the infarct-adjacent zone (r=0.72; P=0.001). Conclusion—Diffusion-tensor cardiac MR suggests that sequential zonal improvement of tissue integrity and fiber architecture remodeling both associate with sequential recovery of zonal wall thickening of the left ventricle from recent to chronic MI.