Shyh-Jen Wang

Differentiation of single solid lesions in the lungs by means of single-photon emission tomography with technetium-99m methoxyisobutylisonitrile

The value of technetium-99m methoxy-isobutylisonitrile (MIBI) single-photon emission tomography (SPET) of the chest in differentiating lung carcinomas of various histological types and benign lesions was assessed in 54 patients (47 males and 7 females aged 19–77 years) with single solid lung masses. Chest radiography had indicated that 46 of the lesions were malignant (8 small cell carcinomas, 14 epidermoid carcinomas, 18 adenocarcinomas and 6 undifferentiated large cell carcinomas) and eight, benign. Ten, volunteers who also agreed to undergo 99mTc-MIBI SPET of the chest served as a control group. The results showed that only 65% (30/46) of the lung malignancies were detected by 99mTc-MIBI SPECT, including 63% (5/8) of the small cell carcinomas, 64% (9/14) of the epidermoid carcinomas, 72% (13/18) of the adenocarcinomas and 50% (3/6) of the undifferentiated large cell carcinomas. However, 75% (6/8) of the benign lesions were also detected. The diagnostic sensitivity, specificity and accuracy in differentiating malignant and benign lesions were 65%, 57% and 70%, respectively. We conclude that 99mTc-MIBI is of limited use in the differentiation of single solid lesions in the lungs.

Increased accuracy of the carbon-14d-xylose breath test in detecting small-intestinal bacterial overgrowth by correction with the gastric emptying rate

To date, there is no general agreement as to which test is to be preferred for the diagnosis of small-intestinal bacterial overgrowth. The 1-g carbon-14d-xylose breath test has been proposed as a very sensitive and specific test for the diagnosis of bacterial overgrowth. However, in patients with severe gastrointestinal motor dysfunction, the lack of consistent delivery of14C-d-xylose to the region of bacterial contamination may result in a “negative” result. The aim of this study was to determine whether the accuracy of14C-d-xylose breath test for detecting bacterial overgrowth can be increased by correction with the gastric emptying rate of14C-d-xylose. Ten culture-positive patients and ten culture-negative controls were included in the study. Small-intestinal aspirates for bacteriological culture were obtained endoscopically. A liquid-phase gastric emptying study was performed simultaneously to assess the amount of14C-d-xylose that entered the small intestine. The results of the percentage of expired14CO2 at 30 min were corrected with the amount of14C-d-xylose that entered the small intestine. There were six patients in the culture-positive group with a14CO2 concentration above the normal limit. Three out of four patients with initially negative results using the uncorrected method proved to be positive after correction. All these three patients had prolonged gastric emptying of14C-d-xylose. When compared with cultures of small-intestine aspirates, the sensitivity and specificity of the uncorrected14C-d-xylose breath test were 60% and 90%, respectively. In contrast, the sensitivity and specificity of the corrected14C-d-xylose breath test improved to 90% and 100%, respectively. In conclusion, using the gastric emptying rate of14C-d-xylose as a correcting factor, we found a higher sensitivity and specificity for the14C-d-xylose breath test in the detection of small-intestinal bacterial overgrowth than were achieved with the conventional method.

Influence of age on gastric emptying in healthy Chinese.

Radionuclide gastric emptying studies, including solid and liquid phases, were used to evaluate the gastric motility of healthy Chinese. Forty-eight patients (18-76 years old) and 38 volunteers (27-79 years old) accepted solid or liquid food gastric emptying studies, respectively. The solid meal was two fried eggs mixed with 500 µCi Tc-99m phytate and two pieces of toast to form a sandwich. The liquid meal was 500 ml of water with 5% glucose and 500 µCi Tc-99m phytate. Studies were performed with the subjects in the supine position and a gamma camera in a left anterior oblique (LAO) position while data were collected for 90 minutes and 30 minutes after finishing the solid and liquid meal, respectively. The gastric emptying time was presented as a half-time (t½) of the food emptying from the stomach. The study results showed that the t½ is 89.0 ± 17.8 in older patients (>60 years old) and 88.0 ± 18.2 in younger patients (≤60 years old) for the solid phase studies (P>0.05), and that the t½ is 46.2 ± 11.1 in older patients (>60 years old) and 31.9 ± 11.3 in younger patients (≤60 years old) for the liquid phase studies (P<0.05). We concluded that the age effects of gastric emptying in healthy Chinese occurred only in the liquid phase.

Influence of age, gender, and ethnicity on nasal mucociliary clearance function.

Nasal mucociliary clearance functions were measured in 46 healthy Chinese adult subjects (21 women and 25 men; age range, 27 to 75 years). A single droplet of Tc-99m MAA was placed on the floor of the nasal meatus about 1 cm behind the mucocutaneous junction, and its course was followed with a gamma camera. The nasal mucociliary clearance function was presented as the velocity (mm/minute) of nasal mucociliary transport of the Tc-99m MAA droplet. The results showed the velocity to be 4.42 pm 2.12 mm/minute (4.61 pm 2.37 mm/minute in the right nostril; 4.24 pm 1.83 mm/minute in the left nostril). When the patients were grouped according to age or gender the velocity was 4.8 pm 1.9 mm/minute (right nostril), 4.4 pm 1.9 mm/minute (left nostril) in the older subjects (60 years and older), and 4.4 pm 2.7 mm/ minute (right nostril), 4.1 pm 1.8 mm/minute (left nostril). In the younger subjects (59 years old and younger) (P > 0.05) the velocity was 5.0 pm 2.7 mm/minute (right nostril), 4.3 pm 1.8 mm/minute (left nostril) in men and 4.1 pm 2.0 mm/minute (right nostril), 4.2 pm 2.0 mm/minute (left nostril), in women (P > 0.05). The authors concluded that the influence of age or gender on healthy Chinese adults is not apparent. In addition, the velocity of flow in Chinese adults is slower than those in other previously reported ethnic studies.

Tc-99m HMPAO Labeled WBC Scan for the Detection of Myocarditis in Different Phases of Kawasaki Disease

Myocardial imaging with Tc-99m HMPAO WBC was used to detect myocarditis of Kawasaki disease in 103 infants and children (66 boys and 37 girls, mean age 3 years and 4 months). The clinical course of Kawasaki disease may be divided into three phases, from the onset of illness onset until all clinical symptoms and signs have disappeared. Twenty-four hour myocardial imaging was performed in anterior, LAO, and left lateral views. The grading system was as follows: score 0 < bone uptake; 1 = bone uptake; 2 > bone uptake; and 3 ≥ liver uptake. If the score was ≥ 2, significant myocarditis was considered. The appearing ratio of myocarditis was 57% (13/23) in the first phase; 65% (15/23) in the second phase; 54% (31/57) in the third phase. No significant difference was demonstrated among the three groups of patients (P > 0.1, by Chi-square test). In conclusion, an occult myocarditis may continue in all three phases of Kawasaki disease, even if the clinical symptoms and signs had improved by the evidence of Tc-99m HMPAO labeled WBC scan to avoid advanced cardiac complication.

The relationship betweenHelicobacter pylori infection and gastric emptying in patients with non-insulin-dependent diabetes mellitus

Forty-four patients with non-insulin-dependent diabetes mellitus (NIDDM) were included in this study. Radionuclide-labelled solid meals were used to calculate gastric emptying times (GETS). The carbon-14 urea breath test (14C-UBT) was used to diagnoseHelicobacter pylori (HP) infection. The patients were separated into groups according to the following two criteria: (1) HP infection was diagnosed on the basis of a14C-UBT value of ≥1.5; (2) the GET was defined as abnormal when it was ≥117.1 min. The results showed that 61% (27/44) of the NIDDM patients had an HP infection, and 59% (26/44) had an abnormal GET. The incidence of abnormal GET in positive14C-UBT patients (62%) was higher than that in negative14C-UBT patients (56%). Similarly, the incidence of positive14C-UBT in abnormal GET cases (62%) was higher than that in normal GET cases (56%). However, according to chi-square tests the differences were not significant. In conclusion, no significant relationship between HP infection and GET was found in patients with NIDDM.

Accuracy of a rapid 10-minute carbon-14 urea breath test for the diagnosis of Helicobacter pylori-associated peptic ulcer disease

Urease in the human gastric mucosa is a marker for infection with Helicobacter pylori (HP), an organism which is associated with peptic ulcer disease. To detect gastric urease, we examined 184 patients (144 males, 40 females; mean age: 49.8±15.6 years) with suspected peptic ulcer disease. Fasting patients were given orally 5 μCi of carbon-14 labelled urea. From each patient only one breath sample was collected in hyamine at 10 min. The amount of 14C collected at 10 min was expressed as follows: [(DPM/mmol CO2 collected)/(DPM administered)] × 100 × body weight (kg). The presence of HP colonization was determined by examination of multiple endoscopic prepyloric antral biopsy specimens subjected to culture or a rapid urease test. For the purpose of this study, HP-positive patients were defined as those with characteristic bacteria as indicated by a positive result of either the culture or the rapid urease test; HP-negative patients were defined as those with negative findings on both the culture and the rapid urease test. Of the 184 cases, 99 (53.8%) were positive for HP infection, and 85 (46.2%), negative. The sensitivity and specificity of the rapid 10 min 14C-urea breath test for the diagnosis of HP-associated peptic ulcer disease were evaluated by a receiver operating characteristic (ROC) curve with a variable cut-off value from 1.5 to 4.5. When a cut-off value of 1.5 was selected, the sensitivity was 100% and the specificity, 83.5%; when a cut-off value of 4.5 was selected, the sensitivity was 54.5% and the specificity, 97.6%.

Tc-99m sestamibi myocardial SPECT in syndrome X.

The authors reviewed the stress Tc-99m MIBI SPECT results and clinical data of 15 patients with syndrome X. The results of exercise EKG and resting left ventricular ejection fraction (LVEF) were compared with the results of Tc-99m MIBI SPECT. Of the 15 patients, 9 (60%) had a normal Tc-99m MIBI SPECT study and 6 (40%) had an abnormal Tc-99m MIBI SPECT. The authors found that 1) an abnormal Tc-99m MIBI SPECT was common in syndrome X, 2) the results of the exercise EKG were not related to perfusion defects on Tc-99m MIBI SPECT, and 3) for patients with an abnormal Tc-99m MIBI SPECT, the incidence of an abnormal resting LVEF and cardiac abnormalities were not higher than in patients with normal Tc-99m MIBI SPECT studies.

Detection of esophageal carcinoma using Tc-99m MIBI SPECT imaging.

&NA; Thirty male patients, ranging in age from 41‐78 years, with esophageal carcinomas underwent Tc‐99m MIBI SPECT of the chest to evaluate the value of Tc‐99m MIBI in the detection of esophageal carcinoma. In addition, Tc‐99m MIBI SPECT of the chest was performed, for comparative purposes, in 10 normal patients who were referred because of suspected ischemic heart disease. Of the 30 patients with esophageal carcinoma, 22 epidermoid carcinomas (73%) were detected using Tc‐99m MIBI chest SPECT, while eight carcinomas (27%) were not detected. In comparison, 10 of the control patients (100%) were not detected on the Tc‐99m MIBI chest SPECT. In addition, the diagnostic sensitivity was not related to cell differentiation, the location, or the size of the carcinomas. These results suggest that the Tc‐99m MIBI chest SPECT could be a helpful test to detect esophageal carcinoma.

The role of Tc-99m MDP and Ga-67 imaging in the clinical evaluation of malignant fibrous histiocytoma

The purpose of this study was to evaluate the value of bone and Ga-67 imaging in patients with malignant fibrous histiocytoma (MFH). Thirty-four patients with biopsy-proven MFH were studied. Of these patients, 15 underwent Ga-67 imaging, 26 underwent Tc-99m MDP imaging, and 7 underwent both imaging procedures. In evaluation of the primary tumors, intense Ga-67 uptake was observed in 14 of 15 patients with a diagnostic sensitivity of 93.3%. However, positive bone imaging results were observed in only 10 of 26 patients with a diagnostic sensitivity of 38.5%. Most of these were secondary to Tc-99m MDP uptake in adjacent bone invaded by the primary tumor. Only two patients, of the 18 patients without direct bone invasion, had increased radioactivity in the tumors (11.1%). In evaluation of the metastatic lesions, increased Ga-67 uptake was observed in 8 of 8 metastatic sites (100%). However, Tc-99m MDP could only detect 5 of 12 metastatic sites (41.7%), which were all diagnosed to be bone metastases. None of the extraskeletal metastasis could be detected by Tc-99m MDP imaging. Ga-67 scintigraphy appears to be a very useful tool in the evaluation of both primary and metastatic lesions of MFH and is assumed to be useful in the follow-up. However, it is emphasized that bone scintigraphy is useful only when the tumor invades the skeletal system and is of limited value in the evaluation of extraskeletal lesions.