Hui- Cheng

Activation of the hypothalamus characterizes the acupuncture stimulation at the analgesic point in human: a positron emission tomography study.

We performed a positron emission tomography study, using regional cerebral blood flow as the index of brain activity, to address the specificity of brain activation pattern by acupuncture stimulation of short duration at the classical analgesic point. Needling manipulation at 2 Hz was performed at a classical point of prominent analgesic efficacy (Li 4, Heku) and a near-by non-classical/non-analgesic point, respectively, in normal subjects. Regions activated by acupuncture stimulation at Li 4 included the hypothalamus with an extension to midbrain, the insula, the anterior cingulate cortex, and the cerebellum. Of note, it was only the stimulation at Li 4 that activated the hypothalamus under the similar psychophysical ratings of acupuncture sensation (deqi) as elicited by the stimulation at the two points, respectively. The data suggested that the hypothalamus might characterize the central expression of acupuncture stimulation at the classical analgesic point and serve as one key element in mediating analgesic efficacy of acupuncture stimulation.

Hemodynamic segmentation of MR brain perfusion images using independent component analysis, thresholding, and Bayesian estimation

Dynamic‐susceptibility‐contrast MR perfusion imaging is a widely used imaging tool for in vivo study of cerebral blood perfusion. However, visualization of different hemodynamic compartments is less investigated. In this work, independent component analysis, thresholding, and Bayesian estimation were used to concurrently segment different tissues, i.e., artery, gray matter, white matter, vein and sinus, choroid plexus, and cerebral spinal fluid, with corresponding signal–time curves on perfusion images of five normal volunteers. Based on the spatiotemporal hemodynamics, sequential passages and microcirculation of contrast‐agent particles in these tissues were decomposed and analyzed. Late and multiphasic perfusion, indicating the presence of contrast agents, was observed in the choroid plexus and the cerebral spinal fluid. An arterial input function was modeled using the concentration–time curve of the arterial area on the same slice, rather than remote slices, for the deconvolution calculation of relative cerebral blood flow. Magn Reson Med 49:885–894, 2003.

MR perfusion studies of brain for patients with unilateral carotid stenosis or occlusion: evaluation of maps of "time to peak" and "percentage of baseline at peak".

Maps of “time to peak” (TTP) and “percentage of baseline at peak” (PBP) were compared with maps of conventional brain perfusion parameters, namely, mean transit time (MTT) and relative cerebral blood volume (rCBV). We performed MR perfusion studies in 11 patients. All of them had occlusion or high-grade stenosis of the unilateral carotid artery. Three areas of old infarct, 4 areas of new infarct, and 10 areas of brain without infarct were evaluated specifically. In all these cases, the TTP maps appeared similar to the MTT maps. They showed increases, normal values, or decreases at the same time in all areas evaluated. Most areas of abnormally decreased CBV had increased signal in PBP maps. In conclusion, the TTP map provided the same qualitative information as MTT. PBP seemed correlated inversely to CBV and was less sensitive in demonstrating abnormality.

CT of Globe Rupture: Analysis and Frequency of Findings

OBJECTIVE The objective of our study was to evaluate the CT characteristics of globe rupture. MATERIALS AND METHODS The medical records of patients seen in the emergency department with blunt, penetrating, or explosive orbit injury were retrospectively reviewed. A total of 75 patients (76 injured globes) were included (56 males and 19 females; average age, 45.1 years; age range, 5-95 years). CT examinations were reviewed by two experienced radiologists without knowledge of ophthalmologic findings, original orbital CT images, or surgical outcomes. RESULTS Of the 76 globe injuries, 33 (43%) were ruptured and 43 (57%) were nonruptured. There were significant differences between the ruptured and nonruptured globes with respect to intraocular hemorrhage, lens dislocation and destruction, an intraocular foreign body, intraocular gas, anterior chamber depth (ACD), and globe deformity and wall irregularity (p < 0.05). There was good interrater agreement between the two radiologists (kappa value range, 0.63-0.96). The average sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of CT for the detection of globe rupture based on readings by two radiologists were 76%, 85%, 80%, 82%, and 81%, respectively. CONCLUSION Although CT is extremely useful in the evaluation of ocular trauma, it should not be solely relied on for the diagnosis of globe rupture because of the potentially catastrophic consequences of an undiagnosed injury. A difference in ACD can be diagnostic of globe rupture.

Breast Cancers Detected by Breast MRI Screening and Ultrasound in Asymptomatic Asian Women: 8 Years of Experience in Taiwan

Background: This study investigated one-stop breast screening combining magnetic resonance imaging (MRI) and ultrasound (US) in asymptomatic Asian women. Methods: 3,586 asymptomatic women (mean age, 45.3 years) were retrospectively analyzed by breast MRI followed by US. US-guided biopsy was performed when the MRI-detected lesion was confirmed by US. When the lesion was not detected on the initial US, a second-look US guided by MRI findings was performed. Then biopsy was done. MRI-positive and US-negative patients were followed up according to MRI lesion size, MRI lesion morphology, and mammographic diagnosis. Results: In total, 115 subjects had suspicious malignant lesions and received US-guided biopsy, and 47 malignant lesions, including 35 invasive cancers and 12 carcinoma in situ (CIS) lesions, were diagnosed. More than half (22/35, 63%) of the women with invasive cancer were <50 years of age, and 27 (57.4%) of the 47 cancer cases had early breast cancers. Two invasive cancers (5.7%) and 7 CIS lesions (58.3%) were found at the second-look US. The overall cancer incidence was 1.31% (47/3,586) and increased to 2.2% (78/3,586) if precancerous lesions were included. Subjects aged 41-50 years had the highest incidence of cancer detection (1.97%). Five MRI and US-negative cases had cancers found 1 year after the screening. Conclusions: The results from the one-stop breast screening in this study showed that combining MRI and US is an efficient multimodality tool for screening asymptomatic Asian women in a metropolitan area of Taiwan who had concerns about the diagnosis and radiation of mammography.