Biomedical subjects

Chien-Fang Yang

Publications and source records attributed to Chien-Fang Yang.

26 records · Page 2Linked to original sources

PubMed2002

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.

Adult↗

PubMed2002

Restoration of thrombosed Brescia-Cimino dialysis fistulas by using percutaneous transluminal angioplasty.

PURPOSE: To evaluate the authors' experience with a technique for management of thrombosed Brescia-Cimino arteriovenous fistula. MATERIALS AND METHODS: Forty patients with 42 thrombosed arteriovenous fistulas were percutaneously treated. Thrombosis occurred within 24 hours of attempted angioplasty in five fistulas, between 24 and 72 hours in 27, and longer than 72 hours in 10. Thrombosed fistulas were approached in a retrograde fashion followed by direct balloon dilation with 5-8-mm balloon catheters. If retrograde catheterization failed to cross the arterial anastomosis, an antegrade puncture directly into the thrombosed drainage vein close to the anastomosis was performed with ultrasonographic guidance, as an aid to catheterize the arterial inflow. Thrombolytic therapy with infusion of urokinase directly into the thrombus was performed in selected patients with visible thrombus that had compromised blood flow in the partially restored vascular access. Postintervention primary and secondary patency was calculated by using Kaplan-Meier analysis. Patency rates between patients without and with urokinase infusion were examined by using the log-rank test. RESULTS: Anatomic success was achieved in 39 (93%) of 42 fistulas; and clinical patency, in 38 (90%) of 42 fistulas. Postintervention primary and secondary patencies (including initial technical failure) at 6, 12, and 18 months were 81% and 84%, 70% and 80%, and 63% and 80%, respectively. No significance of patency rate between patients without and with urokinase infusion was found (P =.912). Three patients died of unrelated causes at 1, 2, and 5 months after the procedures. No major complications were encountered. CONCLUSION: High anatomic success and excellent clinical patency can be achieved in the salvage of thrombosed arteriovenous fistulas. Percutaneous restoration of arteriovenous fistulas should be attempted before surgical recreation to optimize outcome in patients undergoing hemodialysis.

Adult↗

PubMed2002

Prediction of postoperative lung function in patients with lung cancer: comparison of quantitative CT with perfusion scintigraphy.

OBJECTIVE: Prediction of postoperative lung function is important in preoperative evaluation of patients with lung cancer. Perfusion scintigraphy is the current method to assess the fractional contribution of lung function of the remaining lung. We developed a quantitative CT method and compared it with perfusion scintigraphy for predictions of postoperative forced expiratory volume in 1 sec (FEV1) in patients with lung cancer. SUBJECTS AND METHODS: Forty-four patients with lung cancer undergoing lung resection with preoperative CT and perfusion scintigraphy were enrolled. Quantitative CT used a dual threshold (-500 and -910 H) on standard preoperative CT to semiautomatically extract lung volume without emphysema or tumor and atelectasis, which we defined as "functional lung volume." Prediction was calculated from preoperative FEV1 multiplied by the fractional contribution of functional lung volume of the remaining lung by quantitative CT. Perfusion scintigraphy was the standard method. Predictions were correlated with postoperatively measured FEV1. RESULTS: Both quantitative CT and perfusion scintigraphy predicted postoperative FEV1 well in patients who underwent pneumonectomy (n = 28, r = 0.88 vs r = 0.86) and in lobectomy (n = 16, r = 0.90 vs r = 0.80) (both, p < 0.001). There was good agreement between the two methods by the Bland-Altman method. In the four patients with low measured postoperative FEV1 (<40% predicted normal), quantitative CT had true-positive prediction in four and perfusion scintigraphy, in only two. CONCLUSION: Given its simplicity, we proposed that quantitative CT be widely used in predicting postoperative FEV1.

Carcinoma, Non-Small-Cell Lung↗

PubMed2002

Aberrant course of Swan-Ganz catheter revealing persistent left superior vena cava.

The presence of a persistent left superior vena cava (PLSVC) is the most common congenital disorder of thoracic venous anomaly. Failure of the left anterior cardinal vein to degenerate results in persistent left superior vena cava. It is usually discovered during central venous catheterization or surgical repair of congenital heart disorder. Although most patients with isolated PLSVC or double SVC are asymptomatic, there are some important clinical implications in certain situations, such as central venous catheterization or cardioplegia, which may result in serious complications. In this article, we present a case with PLSVC revealed by chest roentgenogram after pulmonary artery catheterization via left internal jugular vein. We also discuss the role of computed tomography in the diagnosis of PLSVC.

Aged↗

PubMedDate not supplied

Percutaneous stent-graft repair of a mycotic pulmonary artery pseudoaneurysm.

Ruptured mycotic pulmonary pseudoaneurysm is a lethal complication. Emergent surgical repair is usually recommended, but still associated with a high mortality rate. We present a patient in whom mycotic pulmonary pseudoaneurysm was a complication after surgical lobectomy 2 weeks earlier. This patient had suffered from repeated massive hemoptysis. After emergent surgical repair of the ruptured pulmonary artery stump, another episode of massive hemorrhage occurred. The pulmonary arteriogram revealed a segmental stenosis and a large, wide-necked, lobulated pseudoaneurysm at the left proximal pulmonary artery. We deployed a balloon-expandable stent-graft (48 mm in length mounted on a 12 mm x 40 mm angioplasty balloon) across the stenotic segment and the neck of the pulmonary pseudoaneurysm. Hemostasis was achieved immediately and, under a 4-week antibiotic treatment, patient was transferred to a local hospital for medical care. This case report demonstrates the benefit of minimally invasive endovascular therapy in a critically ill patient. A literature review of the etiology and management of mycotic pulmonary pseudoaneurysm is included.

Aneurysm, False↗

PubMedDate not supplied

Magnetic resonance imaging and diffusion-weighted images of cystic meningioma: correlating with histopathology.

BACKGROUND AND PURPOSE: Cystic meningiomas are quite rare, accounting for between 2% and 4% of all intracranial meningiomas. To better understand all the types of cystic meningiomas with magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI) and histopathology, we attempted to correlate the MRI and DWI features of cystic meningiomas with the histopathological findings. METHODS: We collected 15 cases of cystic meningiomas diagnosed between 1993 and 2000 (5 men and 10 women, 41-80 years old). Fifteen patients had conventional MRI and 14 patients had CT scan. DWI was also performed in three patients. Apparent diffusion coefficient (ADC) images were also done. In the classification of cystic meningiomas, we adopted Worthington's classification, which divides cystic meningiomas into five groups. RESULTS: Tumor resection was performed in all patients. Tumor locations were as follows: convexity (10), falx (2), pterion (2) and lateral ventricle (1). Regarding the types of cystic lesion, type I (3), type II (3), type III (3), type IV (1) and type V (5) were found. Histopathologically, there were six atypical, four meningothelial, two malignant, one fibroblastic, one angiomatous and one transitional. Intratumoral cystic meningiomas were more common in atypical types. Peritumoral cystic meningiomas were more common in meningothelial and atypical types. The cystic portion of the three cystic meningiomas was hypointense or mildly hyperintense on DWI. ADC ratio (ADCR) of DWI for cyst part of two type I cystic meningiomas was 1.25 and 0.82; for cyst part of one type III was 4.04. CONCLUSIONS: It is important to recognize the neuroimaging features of the cystic meningiomas. Conventional MRI and DWI may play an important role in the preoperative radiological evaluation and the recognition of these types of cysts for proper surgical treatment.

Adult↗

PubMedDate not supplied

The feasibility of low-dose CT for pulmonary metastasis in patients with primary gynecologic malignancy.

PURPOSE: To assess the feasibility of low-dose CT (LDCT) in the detection of pulmonary metastases in patients with primary gynecologic malignancies and also to compare the performance of chest digital radiography (DR) and LDCT for their delectability of pulmonary metastases, with use of standard-dose CT (SDCT) as the reference standard. MATERIALS AND METHODS: Thirty female patients with primary gynecologic malignancies (age range, 20-76 years; mean age, 50 years) underwent DR, noncontrast LDCT and contrast-enhanced SDCT, which were performed within an interval of 2 weeks. We used lung nodule, mediastinal lymphadenopathy (>10 mm in the short axis) and pleural changes (including effusion, irregular thickening, or nodularity) as the cardinal imaging findings of lung metastases. A five-point scoring system was designed to indicate the probability of lung metastasis from primary gynecologic malignancies. The five-point scores of DR, LDCT, and SDCT were analyzed by receiver operating characteristic (ROC) curve. RESULTS: SDCT probability scores of +2 and -2 were set to indicate true positive and true negative for pulmonary nodule, mediastinal lymphadenopathy, and pleural effusion, respectively. All the areas under the ROC curve of LDCT appeared to be larger than those of DR[pulmonary nodule: 0.96 [95% confidence interval (CI): 0.92-1.01] vs. 0.74 [95% CI: 0.57-0.91], 0.82 [95% CI: 0.70-0.95] vs. 0.61 [95% CI: 0.50-0.77]; mediastinal lymphadenopathy: 0.98 [95% CI: 0.93-1.03] vs. 0.90 [95% CI: 0.79-1.01], 0.94 [95% CI: 0.82-1.06] vs. 0.66 [95% CI: 0.44-0.88]; and pleural effusion: 0.98 [95% CI: 0.93-1.03] vs. 0.56 [95% CI: 0.29-0.82], 0.90 [95% CI: 0.74-1.05] vs. 0.46 [95% CI: 0.23-0.68]]. CONCLUSION: The performance of LDCT were comparable to those of SDCT and superior to those of DR for detection of pulmonary nodule, mediastinal lymphadenopathy, and pleural effusion. By using LDCT, there was no need of intravenous contrast injection and less radiation exposure. We propose a protocol including standard-dose abdominal CT and low-dose chest CT for the initial and follow-up stagings of primary gynecologic malignancy. The use of chest DR is unnecessary.

Adult↗

PubMedDate not supplied

Metallic stent placement in hemodialysis graft patients after insufficient balloon dilation.

OBJECTIVE: We wanted to report our experience of metallic stent placement after insufficient balloon dilation in graft hemodialysis patients. MATERIALS AND METHODS: Twenty-three patients (13 loop grafts in the forearm and 10 straight grafts in the upper arm) underwent metallic stent placement due to insufficient flow after urokinase thrombolysis and balloon dilation. The indications for metallic stent deployment included 1) recoil and/or kinked venous stenosis in 21 patients (venous anastomosis: 17 patients, peripheral outflow vein: four patients); and 2) major vascular rupture in two patients. Metallic stents 8-10 mm in diameter and 40-80 mm in length were used. Of them, eight stents were deployed across the elbow crease. Access patency was determined by clinical follow-up and the overall rates were calculated by Kaplan-Meier survival analysis. RESULTS: No procedure-related complications (stent fracture or central migration) were encountered except for a delayed Wallstent shortening/migration at the venous anastomosis, which resulted in early access failure. The overall primary and secondary patency rates (+/-standard error) of all the vascular accesses in our 23 patients at 3, 6, 12 and 24 months were 69%+/-9 and 88%+/-6, 41%+/-10 and 88%+/-6, 30%+/-10 and 77%+/-10, and 12%+/-8 and 61%+/-13, respectively. For the forearm and upper-arm grafts, the primary and secondary patency rates were 51%+/-16 and 86%+/-13 vs 45%+/-15 and 73%+/-13 at 6 months, and 25%+/-15 and 71%+/-17 vs 23%+/-17 and 73%+/-13 at 12 months (p = .346 and .224), respectively. CONCLUSION: Metallic stent placement is a safe and effective means for treating peripheral venous lesions in dialysis graft patients after insufficient balloon dilation. No statistically difference in the patency rates between the forearm and upper-arm patient groups was seen.

Aged↗