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Biomedical subjects

A G Bledin

Publications and source records attributed to A G Bledin.

15 recordsLinked to original sources
PubMed1984

Technetium-99m-labeled macroaggregated albumin arteriography for detection of abnormally positioned arterial catheters during infusion chemotherapy.

The arterial catheter position of 500 courses of intra-arterial chemotherapy were monitored by intraarterially introduced Technetium-99m macroaggregated albumin (MAA) particles. Seventeen instances of abnormally positioned catheters (3.4%) were detected by MAA arterial perfusion (MAAAP). All these abnormally positioned catheters were subsequently repositioned resulting in improved tumor perfusion. Plain radiographs obtained in eight instances failed to reveal the abnormally positioned catheter in four, while all eight of these abnormally positioned catheters were detected by MAAAP. Abnormally positioned catheters detected by MAAAP were either immediately after arterial catheter placement (nine instances) or during the course of chemotherapy (eight instances). Of the right instances of displaced catheters during intra-arterial chemotherapy, six instances were accompanied by clinical signs and symptoms suggestive of displaced catheter. Arteriovenous shunting was documented in 5 of 12 hepatic MAAAP studies as evidenced by increased lung activity. When the catheters were displaced in these cases, the lung activity changed: completely disappearing in two instances; decreasing in two instances and remaining unchanged in one.

Antineoplastic Agents↗
PubMed1984

Chemotherapy of cervical carcinoma: use of Tc-99m-MAA infusion to predict drug distribution.

Nineteen patients with cervical cancer had infusion of Tc-99m-macroaggregated albumin particles (MAA) via bilateral internal iliac artery catheters to aid in dividing chemotherapeutic dose appropriately between the two catheters. Unequal drug distribution was used to minimize extrapelvic complications (local gluteal burns) by reducing the dose to the side with the greatest gluteal perfusion, or to increase the dose to the tumor regions that showed heightened perfusion. Pulmonary uptake, due primarily to arteriovenous shunting in the tumor bed, was seen in all patients. The authors suggest that bulk reduction of locally advanced cervical carcinoma in patients without prior irradiation may be achieved by intra-arterial chemotherapy with tolerable toxicity.

Antineoplastic Agents↗
PubMed1984

Changes of arterial blood flow patterns during infusion chemotherapy, as monitored by intra-arterially injected technetium 99m macroaggregated albumin.

Arterial catheter tip position and arterial flow was monitored by intra-arterial infusion of 99Tcm macroaggregated albumin in patients treated by intra-arterial chemotherapy. Variations in arterial flow pattern as monitored by macroaggregated albumin perfusion studies were encountered in 16 patients without apparent change in the catheter position as monitored by arteriographic and/or radiographic examinations. Possible mechanisms causing changes in arterial flow pattern include: (a) development of collateral circulation, (b) arterial spasm, (c) progressive arteritis causing thrombi with or without associated spasm, and (d) laminar flow. It is important to recognise that changes in perfusion patterns are not always accompanied by change in the position of the arterial catheter.

Angiography↗
PubMed1983

Monitoring hepatic artery spasm for chemotherapeutic infusion by using Tc-99m labeled macroaggregated albumin.

During angiographic placement of an intra-arterial hepatic catheter, a spasm was encountered in the proper hepatic artery. Subsequent angiography, however, revealed normal arteries. Tc-99m MAA intra-arterial infusion was then performed which showed a hepatic artery spasm. Twenty-four hours after the initial hepatic arterial spasm, a repeat injection of Tc-99m MAA revealed that the spasm was no longer present and, therefore, that intra-arterial chemotherapy could be administered.

Adult↗
PubMed1983

Demonstration of portosystemic shunts by radionuclide venogram.

In two patients with inferior vena caval obstruction, radionuclide venography using 99mTc-macroaggregated albumin demonstrated diffuse radioactivity in the liver, indicating portosystemic shunts. Follow-up venography after anticoagulation therapy showed disappearance of the hepatic activity in one patient.

Adult↗
PubMed1983

Comparison of radionuclide images and radiographs for skeletal metastases from renal cell carcinoma.

68 metastatic bone lesions proven by biopsy, follow-up radionuclide bone imaging, or radiographs in 18 patients with surgically confirmed renal cell carcinoma were retrospectively analyzed. Bone imaging demonstrated 62 lesions (91%): 48 definite, 7 questionable 'hot' lesions, and, 2 definite, 5 questionable 'cold' lesions. The spine was the most common site. 15 patients had more than one metastasis. 27 lesions were undiscovered by radiographs. Serum alkaline phosphatase was elevated in 12 of 18 patients. It is concluded that radionuclide bone imaging is more sensitive than radiographic examination for bony metastasis from renal cell carcinoma, and that it is important to recognize 'cold' metastatic lesions on the bone imaging in patients with renal cell carcinoma.

Adenocarcinoma↗
PubMed1983

Arterial perfusion with Tc-99m macroaggregated albumin (MAAAP) in monitoring intra-arterial chemotherapy of sarcomas.

Thirty infusion studies with Tc-99m-labeled macroaggregated albumin were carried out in 21 patients who had histologically proven peripheral tumors. Three patterns of tumor perfusion were noted: increased central radioactivity in 13 patients, decreased central radioactivity with or without increased peripheral radioactivity in four, and absence of radioactivity in four. In the last category, all four patients had no evidence of tumor neovascularity by contrast angiography. In all 21 patients the intraneoplastic patterns showed very good correlation between contrast angiography and radionuclide angiography. Pulmonary tracer uptake was documented in all 14 patients who had counts performed over the lungs; one had no evidence of tumor neovascularity by either angiographic study, and only 8 of the 13 remaining (61%) showed evidence of appreciable tumor arteriovenous shunting by contrast angiography. Decreased tumor perfusion, presumably due to vessel spasm, was found in one patient.

Adolescent↗
PubMed1982

99mTc-labeled macroaggregated albumin in intrahepatic arterial chemotherapy.

One hundred eighty-four 99mTc-labeled macroaggregated albumin (99mTc-MAA) perfusion studies were carried out in 39 patients with histologically proven primary (four) and metastatic (35) hepatic neoplasms. Three different patterns of tumor perfusion were observed: (1) increased central radioactivity (33%); (2) decreased central radioactivity (33%); and (3) mixed and/or diffuse radioactivity (33%). Extrahepatic perfusion as evidenced by radioactive localization in the region of the stomach, pancreas, and small bowel was noted in 51%. Its presence was associated with a higher incidence of gastrointestinal complications (45% vs. 16%). Tumor arteriovenous shunting was demonstrated in 38%, showing localization of radiotracer activity in the lungs, and decreased as tumors decreased in size. The use of 99mTc-MAA infusion studies in intrahepatic arterial chemotherapy offers an excellent evaluation of catheter placement and tumor perfusion, in addition to helping to avoid gastrointestinal complications.

Adult↗
PubMed1978

Pneumatosis coli secondary to colonic obstruction. A case report.

A case of pneumatosis coli of the caecum and ascending colon with a closed loop obstruction secondary to carcinoma of the descending colon is presented. The caecum was grossly distended and impending rupture was diagnosed. It is postulated that complete transmural rupture of the caecum was prevented by partial decompression of caecal air into the bowel wall.

Aged↗