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Guang-Uei Hung

Publications and source records attributed to Guang-Uei Hung.

At least 19 recordsLinked to original sources
PubMed2006

Development of a new method for small bowel transit study.

BACKGROUND AND PURPOSE: Currently, most studies combine the small bowel transit examination with gastric emptying time examination. There are significant drawbacks to this method. The radiotracer does not enter the small intestine in a bolus and the starting time for transit in the duodenum is difficult to define. This makes the result unreliable. In this study, we used a commercial enteric capsule containing radioactive charcoal to solve these problems. MATERIALS AND METHODS: Activated charcoal powder was mixed with Tc-99m pertechnetate and loaded to the enteric capsule which can resist gastric acid and dissolve only in the small intestine. In-vitro stability experiment was performed by immersing these capsules in a colorless phosphate buffer of variable pH which mimicked the condition in stomach and small intestine. In addition, ten healthy Chinese volunteers were included for in-vivo experiment. Anterior and posterior views of abdomen were obtained at regular 30-minute intervals until the eighth hour after administration of the radioactive enteric capsule. Small bowel transit time was calculated. RESULTS: The enteric capsule remained intact for at least 480 minutes in the solution mimicking gastric content (pH = 3.0) and disrupted at a mean duration of 227.2 minutes at a pH of 6.8 and at a mean duration of 212.4 minutes at a pH of 7.4 in the solution mimicking pancreaticobiliary secretions. In nine of ten volunteers, the small bowel transit time was between 30 to 270 minutes with a mean transit time of 140 min. In one volunteer, we failed to detect the exact time of small bowel transit because the capsule remained in the stomach throughout the study for up to 8 hours. CONCLUSIONS: We consider activated charcoal labeled with Tc-99m pertechnetate using an enteric capsule as the carrier to be a potential radioactive marker for small bowel transit study.

Administration, Oral↗
PubMed2006

Calyceal diverticulum in FDG-PET imaging.

A 46-year-old female underwent a fluorodeoxyglucose F-18 (FDG) positron emission tomography (PET) whole-body scan for tumor screening after showing no symptoms or signs. The PET images showed a large FDG-avid lesion in the left renal pelvis, with a maximum standard uptake value (SUV) of 10.7 at 1 hour and 3.9 at 3 hours. An abdominal computed tomography (CT) scan showed a 3.7-cm cystic lesion with a slightly irregular wall in the left kidney. The immediate impression was that of a complicated cyst. A histopathologic report after surgery confirmed a calyceal diverticulum. To the best of our knowledge, this is the first report of FDG uptake in a case of calyceal diverticulum.

Diverticulum↗
PubMed2006

Effectiveness of delayed 2-day lymphoscintigraphy on sentinel lymph node detection in patients with breast cancer with negative early lymphoscintigraphy.

PURPOSE: Most centers perform lymphoscintigraphy for the detection of sentinel lymph node (SLN) in patients with breast cancer within 2 hours after radiotracer injection. However, the interval between the injection of the radiotracer and surgery may not be long enough. In this study, we evaluated the effectiveness of delayed imaging (more than 15 hours) for SLN detection in patients with negative early images. METHODS: We retrospectively analyzed a database of 401 patients with breast cancer referred for SLN detection. On the day before surgery, lymphoscintigrams were obtained at 30-minute intervals until SLN was detected or 120 minutes. In those patients who failed to localize SLN on the early images, delayed imaging was performed the next morning. RESULTS: Twenty-seven (6.7%) patients failed to show SLN on the early images. In the 27 patients, delayed imaging was available for 14 patients but not for 13 patients resulting from the tight time schedule for surgery. Of the 14 patients with delayed images, SLNs were successfully harvested in 10 patients (71.4%) at surgery. In contrast, in the 13 patients who lacked delayed images, SLN was only harvested in one case (7.7%) at surgery. The intraoperative detection rate for SLN was significantly higher in the 14 patients with delayed images than that in the 13 patients without delayed images. CONCLUSIONS: Two-day delayed imaging is significantly useful to increase the rate of localizing SLN at surgery in patients with a negative early image.

Breast Neoplasms↗
PubMed2006

A comparison of biodistribution between 111In-DTPA octreotide and 111In-DOTATOC in rats bearing pancreatic tumors.

111In-DTPA octreotide (DTPAOC) has been used for detecting somatostatin receptor positive tumor for years. In-111 DOTA-Tyr3-octreotide (DOTATOC) is newly developed for diagnostic and therapeutic purposes. In this study, we compared the biodistribution and tumor uptake ratio after injection of In-111 DTPAOC and In-111 DOTATOC in rats. Twelve rats bearing pancreatic tumors were divided into two groups: six rats were sacrificed at 4 hr after injection of 3.7 MBq of In-111 DTPAOC and another 6 rats were sacrificed at the same time after injection of 3.7 MBq of In-111 DOTATOC. Samples of various organs were obtained and counted to calculate the tissue concentration. In addition, 12 rats bearing pancreatic tumors were scanned at 4, 24, and 48 hr after injection of 37 MBq of In-111 DTPAOC or In-111 DOTATOC. The tumor uptake ratios (T/N ratio) were calculated. The biodistribution data showed that the activity in the tumor as well as in the kidney was significantly higher in the In-111 DOTATOC group than in the In-111 DTPAOC group, although both radiopharmaceuticals had the expected high affinity to the tumor. The T/N ratios in the In-111 DOTATOC group were also significantly higher than those in the In-111 DTPAOC group at 24 hr after injection. We conclude that In-111 DOTATOC showed lower clearance than In-111 DTPAOC in the rats bearing pancreatic tumors, although both of these radiopharmaceuticals showed expected high tumor uptake.

Animals↗
PubMed2005

Incremental value of ischemic stunning on the detection of severe and extensive coronary artery disease in dipyridamole Tl-201 gated myocardial perfusion imaging.

The sensitivity of nuclear myocardial perfusion imaging in detecting coronary artery disease is high. However, false-negative results may be encountered if all the myocardial territories were uniformly affected. Ischemic stunning after dipyridamole-stress on gated SPECT may be an indicator of severe and extensive coronary artery disease, and can help the interpretation of borderline perfusion images and the elimination of false-negatives secondary to relatively balanced lesions in three-vessel disease.

Aged↗
PubMed2005

Tc-99m(V)-DMSA in wound infection after closure of an ileostomy.

We present a 71-year-old man who underwent closure of an ileostomy and had a fever seven days post surgery. Both Tc-99m(V)-dimercaptosuccinic acid (DMSA) and gallium-67 citrate scans showed increased tracer accumulation in the right lower quadrant of the abdomen. Tc-99m(V)-DMSA scintigraphy can be a rapid alternative tool in the detection of wound infection in patients after ileostomy closure.

Aged↗
PubMed2005

Performance of thallium-201 electrocardiography-gated myocardial perfusion single photon emission computed tomography to assess left ventricular function.

This study evaluated the performance of gated single photon emission computed tomography (SPECT) with thallium-201 (201Tl) in assessing left ventricular ejection fraction (LVEF), end-diastolic volume (EDV), and end-systolic volume (ESV) in Taiwanese by determining repeatability and correlation with two-dimensional (2D) echocardiography. A total of 18 patients underwent two sequential gated SPECT acquisitions within 30 minutes in the resting state to assess repeatability. Another 28 patients who underwent gated SPECT and 2D echocardiography within 7 days were included for comparison. The two sequential measurements were well correlated with respect to LVEF, EDV, and ESV (r = 0.97, 0.95, and 0.97, respectively, all p < 0.0001). Bland-Altman analysis revealed that two standard deviations of the absolute difference between the two sequential measurements for LVEF, EDV, and ESV were 6.4%, 16.8 mL, and 8.6 mL, respectively. For LVEF, EDV, and ESV, correlations between redistribution 201Tl-gated SPECT and echocardiography were also excellent (all r = 0.83, p < 0.0001). LVEF was similar with 201Tl-gated SPECT and echocardiography, but EDV and ESV were significantly higher with echocardiography (p < 0.05). Our study revealed that 201Tl-gated SPECT has high repeatability and excellent correlation with echocardiography for the assessment of LVEF and volumes in Taiwanese. These results support the clinical application of gated SPECT in routine 201Tl myocardial perfusion imaging in Taiwanese.

Adult↗
PubMed2005

Value of delayed 18F-FDG-PET imaging in the detection of hepatocellular carcinoma.

BACKGROUND: 18F-Fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) is a very useful imaging technique and is the best modality for the evaluation of many kinds of tumour. However, in the evaluation of hepatocellular carcinoma (HCC), the diagnostic accuracy of routine 60 min static imaging is not satisfactory. Some authors have suggested that delayed 2 h imaging is a better 18F-FDG-PET protocol for tumour detection. However, the value of delayed 3 h imaging has not been clarified. In this study, we performed delayed 2 h and 3 h imaging on patients with HCC and compared their diagnostic accuracy with standard 60 min imaging. METHODS: Twelve patients with HCC were enrolled in this study. Of these 12 patients, four had not been treated and eight had received transcatheter arterial embolization (TAE) therapy for more than 4 months before the PET study. One hour after injection of 18F-FDG, a whole-body scan was performed. In addition, delayed imaging focusing on the liver was also performed 2 h and 3 h after the injection. The standard uptake value (SUV) was calculated for the tumours in each image. RESULTS: The twelve patients had 16 HCCs. Of the 16 HCCs, nine were detected by 18F-FDG-PET scans based on the 1 h images, whereas 10 HCCs were detected based on the 2 or 3 h images. The diagnostic sensitivity increased from 56.3% on the 1 h image to 62.5% on the 2 and 3 h images. In addition, the mean SUV increased from 3.63 at 1 h to 3.86 at 2 h and 3.99 at 3 h after the injection of 18F-FDG. On the other hand, the mean SUV in the normal liver tissue decreased slightly from 2.38 at 1 h to 2.33 at 2 h and 2.31 at 3 h. The tumour to normal liver tissue (T/N) ratio increased from 1.56 at 1 h to 1.68 at 2 h and 1.75 at 3 h. CONCLUSION: In the evaluation of HCC, delayed 2 and 3 h imaging can detect more lesions than standard 1 h imaging. Imaging at 3 h has a better T/N ratio than imaging at 2 h, but does not increase the diagnostic sensitivity.

Adult↗
PubMed2005

FDG-PET findings in barium aspiration.

A 47-year-old man had nasopharyngeal carcinoma (NPC). He received radiotherapy 10 years ago and was cancer-free after the treatment. However, diplopia occurred 1 year ago and became more progressive recently. An FDG-PET scan was performed to rule out the possibility of recurrence. No abnormal FDG uptake was demonstrated in the head and neck. However, an irregular area of increased FDG uptake was noted in the right lower lung. The plain chest x-ray showed barium retention in the same area, which might have resulted from aspiration of barium during gastrointestinal barium examination 2 years ago. A follow-up chest x-ray showed no apparent change and there was no evidence of metastases in the lung 6 months later.

Artifacts↗
PubMed2005

Extraordinarily high F-18 FDG uptake caused by radiation necrosis in a patient with nasopharyngeal carcinoma.

A false-positive F-18 FDG PET scan caused by osteoradionecrosis and inflammation in patients with nasopharyngeal carcinoma (NPC) has been reported. The standard uptake values (SUVs) in these false-positive cases are always below 6 and decrease with time. This report is concerned with a false-positive result with extraordinarily high F-18 FDG uptake, which increased on the delayed 3-hour image. A 63-year-old man with NPC underwent surgical removal and radiotherapy (7400 cGy) in July 2003. In October 2003, the CT scan showed a large soft tissue mass over the nasopharynx. Tumor recurrence was suspected. F-18 FDG PET scan showed an FDG-avid lesion over the nasopharyngeal region with a maximum SUV of 28.8 at 1 hour that increased to 30.4 at 3 hours. Biopsy was performed and the histopathologic examination showed only necrotic tissue and no evidence of tumor cells. Radiation necrosis was diagnosed. No evidence of tumor recurrence was noted during the 10-month follow-up period.

Carcinoma↗
PubMed2005

A pitfall of FDG-PET image interpretation: accumulation of FDG in the dependent area of the urinary bladder after bladder irrigation--the usefulness of the prone position.

In F-18 FDG PET studies, retrograde irrigation of the urinary bladder is usually used to reduce the interference with physiological urinary accumulation of F-18 FDG in patients with possible pelvic lesions. A 34-year-old female who had recently been diagnosed with cervical cancer had an F-18 FDG-PET scan performed for whole-body evaluation. The bladder was irrigated with physiological saline and filled with 200 mL of irrigation fluid through a 3-way balloon catheter inserted before the scan. Two areas with high FDG accumulation were noted in the posterior pelvis. Tumor invasion or metastasis could not be ruled out. Additional focal imaging of the pelvis was performed with the patient in the prone position. The lesion on the left side of the patient was still noted, whereas the lesion on the right had disappeared, which proved that it was a false-positive lesion. Great caution is required when assessing imaging results to avoid misdiagnosis in patients after bladder irrigation.

Adult↗
PubMed2005

Comparison of animal models with soft tissue infection by different bacilli.

In clinical medicine improved diagnostic methods for the detection of infection are needed. A good infectious animal model is very important for the development of a new diagnostic method or drug. The purpose of this study was to establish a good animal model with soft tissue infection. Twenty-four SD rats were divided into four groups (6 in each group). Various bacilli including Staphylococcus aureus (S. aureus), Streptococcus pneumoniae (S. pneumoniae), and Escherichia coli (E. coli) were injected intramuscularly into the left caudal thighs of three groups of rats to create soft tissue infection. In addition, normal saline was injected into the left caudal thighs of ten rats which were used as controls. Before and 48 hr after inoculation of the bacilli, a blood sample (0.5 ml) was taken from each rat and analyzed to determine the white blood cell count and differentiated cell count. In addition, 48 hr after the inoculation, 0.2 mCi of gallium-67 was injected via the tail vein. Gallium scan was performed at 24 hr and 48 hr after administration of the radiotracer. The dorsal view of both hind legs was imaged and analyzed by computers to calculate the lesion-to-normal (L/N) ratio. After imaging, all rats were sacrificed and specimens from portions of the infected thigh muscle were sent for histopathologic investigation to confirm the infection. The increase in both the WBC counts and the segmented polymorphonuclear leukocytes (PMNs) were most significant in the S. aureus group, followed by the S. pneumoniae group, E. coli group and normal control groups. The rats with S. aureus infection had significant gallium uptake at the site of infection and the highest L/N ratio of 2.14 on the 24-hr image and 2.0 on the 48-hr image. The rats with S. pneumoniae had the second highest L/N ratio (1.41 at 24 hr, and 1.48 at 48 hr). The L/N ratio for the E. coli group was 1.27 at 24 hr and 1.35 at 48 hr. No obviously abnormal gallium uptake was demonstrated in the normal controls. We conclude that all three bacilli induced a soft tissue infection in SD rats. S. aureus resulted in the most significant infectious signs.

Animals↗
PubMed2004

Comparison of the effectiveness between a single low dose and fractionated doses of radioiodine in ablation of post-operative thyroid remnants.

Due to the lack of radiation isolation wards in most hospitals in Taiwan, high-dose (exceeding 30 mCi) radioiodine therapy is usually performed in a fractionated manner (successively administering multiple low doses). This study compared the ablating efficacies of post-operative thyroid remnants using a single low dose (30 mCi) and fractionated doses (four doses of 30 mCi given at weekly intervals) in 59 patients with differentiated thyroid cancer who received total or near-total thyroidectomy. Successful ablation was obtained in 20 of 38 patients (52.6%) treated with a single low dose compared with 14 of 21 patients (66.7%) treated in a fractionated manner. There was no statistically significant difference between these two treatment protocols (P = 0.296). As the fractionated-dose protocol has the drawbacks of a much longer hypothyroid state and a higher total expense, we suggest that a single low dose is more feasible than fractionated doses for outpatient ablation therapy.

Adult↗
PubMed2003

Tc-99m MIBI parathyroid scintigraphy and intact parathyroid hormone levels in hyperparathyroidism.

Tc-99m MIBI has been widely used to evaluate hyperparathyroidism based on increased tracer uptake in hyperfunctioning parathyroid tissue. The functional status measurement of parathyroid glands with intact parathyroid hormone (iPTH) levels is also one of the most important diagnostic studies in this disorder. The aim of the current study was to assess the relation between MIBI imaging and iPTH levels. The authors retrospectively reviewed the records of patients with hyperparathyroidism who were referred to their department for Tc-99m MIBI scintigraphy. Sixty-five patients (24 primary and 41 secondary hyperparathyroidism) were included. The iPTH levels ranged from 66.06 to 2,836 pg/ml (normal, 10 to 55 pg/ml). Forty-two patients were MIBI positive and 23 were negative. The iPTH level in the MIBI-positive group was significantly greater than in the negative group in the primary (548 +/- 478 versus 124 +/- 45; = 0.002), secondary (1,155 +/- 692 versus 501 +/- 352; < 0.001), and overall (909 +/- 678 versus 386 +/- 341; < 0.001) groups. For the primary hyperparathyroidism group, 17 of the 24 patients were MIBI positive (71%). When iPTH levels exceeded 200 pg/ml (100%), the diagnostic sensitivity reached 100%. For the secondary hyperparathyroidism group, 25 of 41 patients (61%) were MIBI positive; 24 of 38 patients (63%) had an iPTH level greater than 200 pg/ml, 21 of 27 patients (78%) had an iPTH level greater than 500 pg/ml, and 11 of 12 patients (92%) had an iPTH value greater than 1,000 pg/ml. Tc-99m MIBI parathyroid scintigraphy showed a good correlation with iPTH level for both primary and secondary hyperparathyroidism. Visualization of hyperfunctioning parathyroid glands on Tc-99m MIBI parathyroid scintigraphy was more likely with a higher serum iPTH level in a dose-dependent manner.

Adult↗
PubMed2003

Scintigraphic findings of Mycobacterium avium complex tenosynovitis of the index finger in a patient with systemic lupus erythematosus.

The presented case is a 36-year-old woman with a history of systemic lupus erythematosus for 10 years. She had progressively painful swelling of the right index finger that later proved to be a rare case of tenosynovitis caused by Mycobacterium avium complex. Serial images of 3-phase bone scans, gallium scan, and magnetic resonance imaging demonstrate the area of involvement.

Adult↗