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Biomedical subjects

W J Shih

Publications and source records attributed to W J Shih.

At least 127 records · Page 7Linked to original sources
PubMed1993

[123I]HIPDM pulmonary imaging demonstrates elastase-induced pulmonary emphysema.

Because more than 90 percent of [123I]hydroxyiodobenzyl-propanediamine (HIPDM) is localized in the lung after intravenous injection, the radiopharmaceutical has been proposed as a lung imaging agent. Its potential usefulness for the detection of pulmonary emphysema was evaluated in an animal model of elastase-induced emphysema along with [99mTc]MAA lung perfusion imaging. To induce lung emphysema, Long-Evans rats (200-250 g) were given 400 IU/Kg elastase intratracheally under ether anesthesia. Four weeks after elastase treatment, 15 treated and 15 nontreated rats were paired and simultaneously imaged under a scintillation camera immediately following intravenous injection of 0.25-0.3 mCi[99mTc]MAA. The procedure was repeated 48 hr later using 0.25-0.3 mCi[123I]HIPDM. Activity in the region of interest (ROI) over the lungs was recorded after the injections. Total counts per ROI from each rat were measured and normalized by lung volume. The normalized lung activity ratio of treated/nontreated rats was computed. The mean ratios of HIPDM and MAA were 0.847 and 0.802, respectively. The significant decrease in uptake of both HIPDM (p < 0.021) and of MAA (p < 0.025) in the elastase-treated lungs indicates decrease in functioning vascular endothelium and decrease in number of pulmonary capillary vessels, respectively, reflecting damage in capillaries and small arterioles. The decrease in treated/nontreated ratios lung is consistent with a significant alteration in pulmonary function and a significant increase in mean linear intercept (p < 0.005) in treated lung. Since the imaging reflects pulmonary endothelial receptor function, [123I]HIPDM lung imaging may serve as an alternative diagnostic modality for pulmonary emphysema.

Animals↗
PubMed1993

Diagnostic imagings for primary cardiac fibrosarcoma.

Primary tumors of the heart are rare; primary cardiac fibrosarcoma is even rarer. We report a patient with primary cardiac fibrosarcoma widespread metastases presenting with pulmonary metastases initially. The cardiac lesion was identified by bone-imaging localization on bone scan, by hypodense areas in the cardiac chambers of contrast computed tomography of the chest, and by protruding masses in ventricular cavities causing aortic valve outflow-tract obstruction by echocardiogram. At autopsy, a large tumor invaded the interventricular septum and both ventricular cavities of the heart (880 g in weight), and accounted for these imaging findings. While bone-agent localization in the heart does not differentiate malignant from benign conditions, computed tomography and echocardiography of the interatrial and interventricular septal, and right atrial and biventricular cavitary involvement may differentiate fibrosarcoma from myxoma.

Aged↗
PubMed1993

Lung uptake of Tc-99m HMPAO in cigarette smokers expressed by lung/liver activity ratio.

Tc-99m HMPAO, a lipophilic radiopharmaceutical used for brain imaging, has been reported to localize in smokers' lungs. To quantitate this uptake in the lung, 55 patients, who were referred for brain imaging for dementias or strokes, also underwent lung imaging (anterior lung imaging includes a large part of the liver) after IV injection of the radiopharmaceutical. Regions of interest over the liver and the lung were calculated. Of the 55 patients (ages 13-79), 30 were smokers and 25 were nonsmokers. The smokers had been smoking from 6-59 years, and daily cigarette consumption ranged from 8-50 cigarettes. The mean lung/liver ratio for smoking patients were 0.792 +/- 0.042 (SE); the mean lung/liver ratio for nonsmoking patients was 0.408 +/- 0.019 (SE). Lung/liver ratio uptake was significantly higher in the smoking patients (P < 0.01) than in the nonsmokers. Thus, lung/liver uptake of Tc-99m HMPAO may be used as an indicator of cigarette smoking.

Adolescent↗
PubMed1993

Volume and surface three-dimensional displays of Tc-99m HMPAO brain SPECT imaging in a chronic hypnosedative abuser.

An alcohol- and diazepam-abusing patient underwent brain CT and SPECT imaging studies. The CT scan showed mild brain atrophy, whereas SPECT imaging using Tc-99m HMPAO showed a large lesion in the left cerebral hemisphere. The extent of lesion involvement was appreciated by three-dimensional displays. This finding was associated with a clinical presentation of hypnosedative withdrawal delirium (disorientation, impaired memory, rambling speech with loose associations, paranoia, ideation, restlessness, poor judgment). Tc-99m HMPAO SPECT may provide objective documentation of regional cerebral neurochemical alteration associated with hypnosedative abuse or hypnosedative withdrawal states, whereas surface and volume three-dimensional displays simplify and enhance brain SPECT image interpretation.

Alcohol Withdrawal Delirium↗
PubMed1993

Bilateral photon deficient area along lateral abdominal wall in a Tc-99m DTPA renogram. A sign of massive ascites.

A patient with congestive heart failure and hepatic and renal dysfunction underwent Tc-99m DTPA renal scintigraphic studies in which persistent cardiac blood pool activity, hepatic arterialization, and a longitudinal photon deficient area in each side of the abdominal wall were observed. The increase in hepatic artery inflow was believed to be due to a decrease in portal inflow of the liver. The elevation of portal pressure secondary to heart failure is attributable to the decrease in portal inflow of the liver; this phenomenon could account for the hepatic arterialization. Progressive renal dysfunction with high body background resulted in demonstrable ascites as photon deficient areas. Scintigraphic findings of hepatic arterialization plus an abdominal photon deficient area reflect severe heart failure and renal dysfunction.

Abdominal Muscles↗
PubMed1993

Tc-99m sestamibi uptake by cerebellar metastasis from bronchogenic carcinoma.

Tc-99m sestamibi has been used to detect primary brain and lung tumors. The authors report a patient who underwent brain imaging to differentiate tumor from abscess in the cerebellum because of a ring-like enhancement lesion on a brain CT scan. An abnormal area of increased sestamibi uptake in the right cerebellum was demonstrated planar and on a SPECT imaging. The removed tumor was confirmed to be poorly differentiated metastatic carcinoma.

Aged↗
PubMed1993

Surface and volume three-dimensional displays of Tc-99m HMPAO brain SPECT images in stroke patients by a three-headed gamma camera.

Twenty patients with strokes were studied to evaluate volume and surface three-dimensional (3D) displays in Tc-99m HMPAO brain SPECT imaging using a triple-head gamma camera interfaced with a 64-bit super computer. In each patient, after an intravenous injection of 20 to 30 mCi of Tc-99m HMPAO, a first-pass cerebral flow study and brain SPECT images at 30 to 60 minutes were obtained. Although the cerebral lesion was more clearly delineated with surface 3D and volume 3D, crossed cerebellar diaschisis in seven patients was more clearly exhibited by volume 3D rather than surface 3D imaging. Volume and surface 3D displays enhance continuity of structures and understanding of spatial relationships; these displays view the brain from all angles, and thus the location and extension of lesion(s) in the brain are much easier to appreciate. It is concluded that 1) both surface and volume 3D displays equally enhance SPECT interpretation; and 2) volume 3D display enhances demonstration of crossed cerebellar diaschisis, but surface 3D display does not.

Brain↗
PubMed1993

Enlarged photon-deficient area in expected site of renal allograft on Tc-99m DTPA study. A sign of renal vein thrombosis.

Tc-99m DTPA renal imaging has been routinely used in postrenal transplant evaluation. A patient's Tc-99m DTPA studies after transplantation are presented, showing a large photon-deficient area in the region of the allograft on the third postoperative day. The photon-deficient area is two to three times larger than that seen in the original, functioning allograft on the first postoperative day. Enlarged to a weight of 530 g, the allograft on gross and microscopic examination confirmed renal vein thrombosis. Enlargement of the photon-deficient area at the anatomic site of the allograft indicates a scintigraphic pattern of renal vein occlusion incompatible with a viable allograft.

Adult↗
PubMed1993

Extracardiac 'hot' and 'cold' areas on thallium-201 myocardial SPECT imaging.

A 72-year-old man underwent Persantine 201Tl myocardial SPECT imaging that showed a transient area of extracardiac radiotracer accumulation inferior to the inferior wall of the left cardiac ventricle, and a persistent, rounded, cold area in the liver. CT of the abdomen confirmed a cystic lesion in the liver corresponding to the cold area, and the transient extracardiac tracer accumulation area corresponded to a large aneurysm of the distal descending thoracic aorta. An extracardiac abnormal area of 201Tl localization, 'hot' or 'cold', should be included for scan interpretation to depict thoracic and/or upper abdominal lesions(s).

Aged↗
PubMed1993

Communication between peritoneal cavity and mediastinal lymph nodes demonstrated by Tc-99m albumin nanocolloid intraperitoneal injection.

Lymphatic drainage from the peritoneal cavity to mediastinal lymph nodes has been reported, indicating that abdominal fluid is not immobile. We studied this movement in rats receiving Tc-99m albumin nanocolloid which has smaller particle sizes than does Tc-99m microaggregated albumin colloid used for liver/spleen imaging. The Tc-99m albumin nanocolloid had a radiochemical purity of 99.33%-99.77% with free pertechnetate of 0.23%-0.67%. During pentobarbital anesthesia, thoracoabdominal images were obtained 4-6 hr after intraperitoneal injection of 350 mCi Tc-99m albumin nanocolloid with 5 ml of normal saline. The images showed symmetrical radiotracer localization in the mediastinal lymph nodes. Scintigraphic demonstration of drainage to the mediastinal region from the peritoneal cavity may be explained by flow directly into mediastinum through the lymphatic system, indicating lymphatic patency between the peritoneal cavity and mediastinum. Absence of visualization may indicate lymphatic block. This type of information concerning lymphatic drainage may have clinical impact for a patient with malignant or intractable ascites. The radionuclide technique is easily performed for this assessment.

Animals↗
PubMed1993

Bile leak from gallbladder perforation mimicking bowel activity and a false-negative result in a morphine-augmented cholescintigraphy.

Cholescintigraphy of a patient with bile leak demonstrated intra-abdominal activity that mimicked normal bowel activity. Because the gallbladder was not visualized, morphine was injected intravenously. Gallbladder activity after morphine injection was misleading in the finding of chronic cholecystitis. Concurrent abdominal sonography and computerized tomography revealed a thickened gallbladder wall with a gallstone and pericholecystic fluid collection. Exploratory laparotomy confirmed acute and chronic cholecystitis, cholelithiasis, choledocholithiasis, and a pericholecystic abscess. The false-negative conclusion for acute cholecystitis in the patient's morphine-augmented cholescintigraphy resulted from an acceleration of bile leakage due to pre-existing gallbladder perforation.

Aged↗
PubMed1993

An abnormal gallbladder presenting as a huge, rounded photon-deficient area in radionuclide hepatobiliary imaging.

Tc-99m DISIDA hepatobiliary imaging was used to evaluate a hemophiliac patient presenting with symptoms of acute cholecystitis and gastrointestinal bleeding. There was nonvisualization of this abnormal gallbladder even on 6 1/2-hour delayed DISIDA images. Instead, a huge photon-deficient area was seen in the gallbladder fossa. Ultrasound and computed tomography findings were consistent with an enlarged gallbladder filled with blood.

Adult↗
PubMed1992

The role of nuclear medicine in oncology.

Nuclear Medicine offers screening methods for oncology such as bone and bone marrow scintigraphy. During the last two decades, special procedures have gained widespread application. This paper is centered around the "tumor-specific" radiopharmaceuticals. In patients with thyroid cancer, I-131 still plays a significant role. Ga-67 still has its indications in lymphoma, while in other diseases Tl-201 chloride is now the agent of choice. Especially in thyroid cancer, Tl-201 has proved to be a reliable tumor imaging radiopharmaceutical. More recently, Tc-99m MIBI was introduced for tumor imaging. Tc-99m HMPAO may also be used for tumor scintigraphy, especially in brain lesions. In addition, I-123 IMP has successfully been used for imaging malignant melanoma. Another promising field of tumor diagnosis is receptor imaging. In neuroblastoma and malignant pheochromocytoma, I-131/123 mIBG is the radiopharmaceutical of choice and may be considered as a receptor imaging agent also. First clinical results with In-111 octreotide show potentials as somatostatin-receptor radiopharmaceutical in insulinoma, islet cell carcinoma, medullary and lung cancer, while I-123 estradiol needs some improvement until it may be recommended as diagnostic tool in breast cancer. Since 1978, radiolabeled poly- or monoclonal tumor antibodies and their fragments have gained widespread application. Especially the Tc-99m 225.28S melanoma antibody, I-131 or Tc-99m CEA and In-111/I-131 labeled OC-125 antibodies have proven to be of clinical significance in melanoma, colorectal and ovarian cancer.

Gallium Radioisotopes↗