Biomedical subjects

Guang-Uei Hung

Publications and source records attributed to Guang-Uei Hung.

22 records · Page 2Linked to original sources

PubMedDate not supplied

Worsening of left ventricular ejection fraction induced by dipyridamole on Tl-201 gated myocardial perfusion imaging predicts significant coronary artery disease.

BACKGROUND: Vasodilator stress on myocardial perfusion imaging has been found to induce ischemic stunning, which may present as transient worsening of left ventricular ejection fraction (LVEF) or regional wall motion abnormality. This study aimed to evaluate the significance of stress-induced worsening of LVEF in the diagnosis of coronary artery disease (CAD) on dipyridamole thallium 201 gated single photon emission computed tomography (SPECT). METHODS AND RESULTS: The study included 126 patients who underwent dipyridamole Tl-201 gated SPECT and coronary angiography within 3 months. Poststress and 4-hour rest images were obtained, and LVEF was calculated by use of automated software (QGS 3.0). A decrease in LVEF of 6% or greater from rest to poststress was considered significant, and this threshold was determined by the serial reproducibility assessment of Tl-201 gated SPECT. If worsening of LVEF was used as the criterion for detecting significant CAD (> or = 70% coronary stenoses in > or = 1 vessel), the sensitivity, specificity, positive predictive value, and negative predictive value were 35%, 93%, 90%, and 44%, respectively. CONCLUSION: Dipyridamole-induced worsening of LVEF, as shown by Tl-201 gated SPECT, is a valuable nonperfusion marker of significant CAD. Although the sensitivity of LVEF worsening in detecting significant CAD is only 35%, the specificity is as high as 93%.

Aged↗

PubMedDate not supplied

Relationship of transient ischemic dilation in dipyridamole myocardial perfusion imaging and stress-induced changes of functional parameters evaluated by Tl-201 gated SPECT.

BACKGROUND: This study assessed whether transient ischemic dilation (TID) of the left ventricle is related to ischemic stunning, manifested by stress-induced decrease of left ventricular ejection fraction (LVEF) and worsening of wall motion, by use of dipyridamole-stress and redistribution thallium 201 gated single photon emission computed tomography (SPECT). METHODS AND RESULTS: Ninety-two consecutive patients undergoing dipyridamole Tl-201 gated SPECT were included. Patients with a TID ratio in the highest quartile were defined as having TID. In patients with TID, end-diastolic volume (EDV) and end-systolic volume (ESV) were both significantly greater on dipyridamole-stress images than on redistribution images (P < .001). The degree of enlargement was much greater for ESV than EDV. In patients without TID, EDV and ESV were both decreased after stress (P < .001). Patients with TID had a lower mean LVEF on dipyridamole-stress images than on redistribution images (P < .001). Patients without TID had a higher mean LVEF on dipyridamole-stress images than on redistribution images (P < .001). Patients with TID had a significant worsening of global wall motion on dipyridamole-stress images than on redistribution images (P < .001), but patients without TID did not. CONCLUSION: TID was significantly correlated with ischemic stunning, and the enlargement of ESV was an important factor resulting in TID.

Aged↗

PubMedDate not supplied

The limited use of ultrasound in the detection of abdominal abscesses in patients after colorectal surgery: compared with gallium scan and computed tomography.

BACKGROUND/AIMS: Ultrasound has been suggested to be a first-line test for the detection of intra-abdominal abscess (IAA). However, according to our experience, ultrasound seemed not so effective when applied to the patients after colorectal surgery. Computed tomography (CT) and gallium scan have also been suggested as very useful for the detection of IAA. The purpose of this study was to evaluate the efficacy of sonography and gallium scan in diagnosing intra-abdominal abscess after colorectal surgery and to compare these results with CT. METHODOLOGY: Twenty-three patients with suspected IAA after colorectal surgery at our institution were eligible for the study. A positive IAA was verifed only if pus was drained or on postmortem examination. Negative reports of abscesses were verified by adequate outpatient review following hospital discharge that indicated the clinical absence of an abscess. Within 4 days of the clinical suspicion of abscess, all patients were evaluated by three techniques: sonography, CT and gallium scan. We compared the sensitivity, specificity and accuracy of these modalities. RESULTS: Fourteen of the 23 patients (60.9%) were verified as IAA. We found the sensitivity, specificity, and accuracy of CT scan for the detection of LAA in the patients with colorectal surgery to be 92.9%, 100%, and 95.7%, respectively. The sensitivity, specificity and accuracy of gallium scan were 100%, 77.8% and 91.3%, respectively. Ultrasound had a 42.9% sensitivity, 100% specificity, and 65.2% overall accuracy for diagnosing IAA. CONCLUSIONS: Sonography plays a small role in the detection of IAA in the patients after colorectal surgery. CT and gallium scan are more helpful than sonography for the detection of IAA.

Abdominal Abscess↗

PubMedDate not supplied

Comparison of Tc-99m sestamibi and F-18 FDG-PET in the assessment of multiple myeloma.

BACKGROUND: Tc-99m methoxy-isobutyl-isonitrile (MIBI) has been reported to be a useful tracer in patients with multiple myeloma (MM). Few articles have reported the potential value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in the evaluation of MM. Therefore, the purpose of this study was to compare the diagnostic abilities of the MIBI scan and the FDG-PET scan in the evaluation of MM. MATERIALS AND METHODS: Twelve patients with MM were included. All patients received a radiological skeletal survey, MIBI scan and FDG-PET scan. RESULTS: Thirty-four lesions (19 soft tissue lesions and 15 skeletal lesions) plus 5 cases of bone marrow involvement were detected. The conventional skeletal X-ray survey detected 4 soft tissue lesions (21.1%), 12 skeletal lesions (80%), but no bone marrow involvement (0%). The MIBI scan found 4 cases of bone marrow involvement (80%), 13 soft tissue lesions (68.4%) and 12 skeletal lesions (80%). The PET scan detected 5 cases of bone marrow involvement (100%), 17 soft tissue lesions (89.5%) and 14 skeletal lesions (93.3%). CONCLUSION: Both the MIBI and the FDG-PET scans are useful in the evaluation of patients with MM. However, FDG-PET can detect more lesions than the MIBI scan in patients with MM.

Adult↗