Lack of protective effect of thromboxane synthetase inhibitor (CGS-13080) on single dose radiated canine intestine.

The effect of a thromboxane A2 synthetase inhibitor (CGS-13080) on canine intestine was studied using a single dose of radiation, and radioactive microspheres were used to determine resultant blood flow. Thromboxane A2 causes vasospasm and platelet aggregation and may play a dominant role in radiation injury. However, there was no effect on the intestinal blood flow diminution occurring after radiation in this laboratory model using this thromboxane A2 synthetase inhibitor.

Scintigraphic evidence for relief of airways obstruction in cystic fibrosis.

A simple scheme for quantifying lung perfusion scintigrams was developed to evaluate the efficacy of a therapeutic regimen for the relief of airways obstruction in cystic fibrosis patients. Ten hospitalized patients were given conventional therapy including administration of intravenous antibiotics, mucolytic aerosols, chest physical therapy, and adequate nutrition and hydration as adjuncts to a single bronchoscopic bronchial washing procedure. Quantitative scoring of the lung scintigram was based upon the severity of the perfusion defects in equivalent upper and lower lung fields, as viewed from right and left posterior oblique projections. Seven to ten days following bronchoscopic washing, scintigraphic scores were found to correlate with changes in both the forced vital capacity and the one-second, time forced expiratory volume (r = 0.78, 0.70, respectively; P <.05). The severity of defective lung perfusion indicated the loss of lung volume and perfusion due to airways obstruction and secondary hypoxic vasoconstriction. Chest radiography was less reflective of improvement than lung scintigraphy. It was concluded that serial pulmonary perfusion scintigrams provide a sensitive tool for evaluating the relief of airways obstruction in cystic fibrosis.

Hypertrophied thyroid tissue in a thyroglossal duct remnant.

A 37-year-old woman was evaluated for a neck mass. This was located in the midline below the hyoid bone. Thirty-three years had elapsed since she had undergone subtotal thyroidectomy for hyperthyroidism. Eight years prior to examination, the patient had discontinued her thyroid maintenance medications. She had discovered the mass eight months prior to examination. Thyroid scan (Fig. 1) showed intense uptake in the mass. At operation the mass was attached to the midportion of the hyoid bone by a small fibrous band, as is usual in a thyroglossal duct remnant. Biopsy results showed diffuse thyroid hyperplasia. Thyroglossal duct remnants are known to harbor cysts or thyroid carcinoma, but growths of compensatory hyperplastic tissue are unusual.

Small calvarial bone scan foci--normal variations.

In a series of 3,000 bone scans reviewed retrospectively 21 (0.7%) small calvarial foci were observed. Seventeen of these lesions were found along skull suture lines. No evidence for metastatic disease could be found. Skull radiographs were normal and follow-up bone scans demonstrated no change in the size or location of the lesion. These intense calvarial foci are thought to represent normal variations; among the possibilities are subradiographic cartilaginous rests, sutural foramina, or enlarged Pacchionian granulations.

Measurement of blood flow through surgical anastomosis using the radioactive microsphere technique.

Two different radioactive microspheres (141Ce and 46Sc) were used to measure blood flow to an area of the large intestine in dogs before and after a surgical resection was performed with surgical staples. The healing of an anastomosis is theoretically related to the blood flow to the anastomotic site. Blood flow studies were conducted in three dogs using this technique. The average blood flow preoperatively was 0.558 mL/minute per gram and 1.04 mL/minute per gram postoperatively. The standard deviation was +/- 0.16. These results indicate a statistically significant (P less than .05) increase in blood flow at the anastomotic site six days after anastomosis when compared with the blood flow to the same area before any surgical procedures.

Calyceal pertechnetate as a false-positive focus of ectopic gastric mucosa.

This case report describes a patient in whom concentration of Tc-99m pertechnetate in a renal calyx created a false diagnostic impression of ectopic gastric mucosa. The administration of furosemide demonstrated the benign cause of the focus.

Monoclonal antibodies in nuclear medicine.

Monoclonal antibodies have been a part of biomedical research for nearly a decade, yet a comparable period of time may be required before radiolabeled monoclonal antibodies come into standard practice in the diagnosis and therapy of human disease. Difficulties in identifying appropriate antigens, developing the optimal antibody species, attaching the most effective radiolabel and choosing the best method of administration all confound present investigations. The problems confronting therapeutic applications are, for the most part, an extension of those associated with diagnostic techniques. Still, there is much well-deserved optimism, and progress in all areas of investigation will ultimately come together to resolve most if not all of these problems. It is inevitable that monoclonal antibodies will have significant impact on the practice of nuclear medicine, and presented here is a review of the basic knowledge as well as an update on the current status of radiolabeled monoclonal antibodies in medicine.

Vocal cord paralysis following I-131 ablation of a postthyroidectomy remnant.

Vocal cord paralysis has been reported following I-131 therapy of thyrotoxicosis and following ablation of the whole thyroid. However, this rare complication has not previously been described following I-131 ablation of a postthyroidectomy remnant. We report a patient who required tracheostomy for bilateral vocal cord paralysis following I-131 ablation after near-total thyroidectomy for papillary thyroid carcinoma.

Efficacy of bone and liver scanning in breast cancer patients treated with adjuvant chemotherapy.

One hundred nineteen patients who underwent mastectomy and received adjuvant chemotherapy for breast carcinoma were studied retrospectively. Of these, 102 patients had serial bone scans and 101 patients serial liver scans during a mean follow-up of 59 months. All had negative scans prior to chemotherapy. Twenty-three of 102 patients converted to positive bone scans during follow-up. These 23 patients converted a mean of 29.5 months after surgery. At conversion, 5 of 21 patients had bone pain, and none had elevated alkaline phosphatase. Thirteen of 101 patients developed positive liver scans a mean of 31.5 months after surgery. The liver scan was the first indicator of liver involvement in only 3 of 13 converters. In no case was the liver scan the first indication of metastatic disease. The incidence of bone scan conversion (22%) did not differ significantly from previously reported series of patients not receiving adjuvant therapy, but the mean time to conversion was prolonged (29.5 versus 18.0 months). In addition, none (0/21) of the bone scan converters had elevated alkaline phosphatase at the time of conversion. It is concluded that the interval from initial evaluation to bone scan conversion may be prolonged by adjuvant chemotherapy of breast cancer. It is recommended that patients have bone scans twice yearly for at least 3 to 4 years after surgery. This study emphasizes the singular importance of bone scanning in breast cancer patients who have adjuvant chemotherapy, as the scan may be the only indicator of bone involvement. Liver scans do not appear useful for screening patients without other evidence for metastatic liver involvement.

Efficacy of liver scanning in malignant diseases.

The use of radiocolloid liver scanning as a routine diagnostic procedure to detect liver metastases has been declining as the most effective uses of this test have become better appreciated. Liver scanning to detect hepatic metastases appears to have the greatest efficacy in two circumstances. The first is as a staging procedure in malignancies that metastasize to the liver early, before being suspected clinically or liver function parameters alter. Such malignancies include gastric carcinoma, Wilms' tumor, small cell carcinoma of the lung, and rhabdomyosarcoma. The second effective use of liver scanning is as a confirmatory test in patients with known malignancy who develop abnormal levels of serum liver enzymes, carcinoembryonic antigen titer, hepatomegaly, ascites, or jaundice.

Splenic simulation by left hepatic lobe following splenectomy.

Remodeling of the liver following splenectomy may simulate hypertrophy of an accessory spleen on sulfur colloid scans. Two patients are reported. In one case splenic simulation is attributed to unusual hepatic scarring confirmed at autopsy. In the second the unusual configuration appears to have been caused by molding of the liver. The clinician should be aware of possible splenic simulation in postsplenectomy patients suspected of hypersplenism.

Radionuclide demonstration of ventriculoatrial shunt-cutaneous fistula with cerebrospinal fluid leak.

Radionuclide techniques have commonly been used to assess ventriculovenous shunt function, cerebrospinal fluid dynamics, and for the diagnosis of cerebrospinal fluid leaks. All of these techniques were utilized in this unusual case of retrograde migration of a ventriculoatrial catheter into the neck, with cutaneous fistulization and CSF leak.

Preparation of sterile xenon-133 in saline for tissue perfusion studies.

A simple, inexpensive method of obtaining Xe-133 in sterile saline is presented. The method uses commercial xenon ampules supplied for pulmonary ventilation studies. As much as 10% of the gas activity can be recovered per aliquot by cooling the saline to 4 degrees C. The specific activities obtained are adequate for most tissue perfusion studies.

Measure of blood flow by the multiple radioactive microsphere technique in radiated gastrointestinal tissue.

In this study, two different radioactive microspheres were used to measure blood flow of an irradiated segment of small intestine in four dogs before, and 12 days after, irradiation with 2000 rad. The technique and implications are discussed. Using multiple radioactive microspheres, the study demonstrated an increased blood flow in irradiated tissues twelve days after a single dose of 2000 rad. There was also an increase in blood flow to adjoining nonradiated segments of intestine in the same animal. These observations may be of significance in clinical applications of radiation therapy and surgery. A major surgical concern is the impaired healing of irradiated tissue in the immediate postradiation period. The mechanism of this has generally implicated decreases in the perfusion of irradiated tissue. No decrease in blood flow was shown in this study, suggesting that other mechanisms, e.g., stem cell depletion, should be considered. Further studies of this type are recommended to increase understanding of the blood flow in irradiated tissue.

The efficacy of radionuclide liver and bone scans in the evaluation of gynecologic cancers.

Between 1978 and 1980, 33 patients with cervical cancer, 40 patients with ovarian cancer, and 28 patients with uterine cancer underwent clinical diagnostic staging. Fifty-four patients had bone scans, and 101 patients received liver scans as a part of their staging work-up. No positive bone scan results were found. Eight of 33 patients with Stage IV disease had positive liver scan results consistent with hepatic metastases. Only 1 of 69 patients with Stage I-III disease had a positive test for metastases. While these numbers are small, the authors conclude that bone and liver scanning in asymptomatic patients with early stage gynecologic cancers may not be warranted as staging procedures.

Differentiation of rib fractures from metastases by bone scanning.

The bone scans of 471 cancer patients revealed 103 (22%) with one or more rib lesions. Of 69 patients who had serial studies, five (7%) had proven rib fractures, 13 (19%) had probable fractures, 25 (36%) had proven metastases, and 26 (38%) had probable metastases. By analyzing the intensity and appearance of rib lesions in serial bone scans, it was concluded that there is a high probability that rib lesions detected by bone scanning are fractures if 1) they are focal as opposed to linear, and 2) they decrease in intensity within three to six months or they are aligned so as to involve two or more ribs in the same location.

Tc-99m pyrophosphate myocardial scanning in Chagas' disease.

Chagas' disease is a serious protozoan infection affecting up to 20% of populations in some endemic areas. Myocarditis and cardiomyopathy occur in 50% of patients who go on to develop chronic Chagas' disease. We have studied a patient with no overt cardiac symptoms who revealed intense myocardial uptake of Tc-99m pyrophosphate. The significance of this finding in relation to early detection and progress of therapy is explored.

Spinal cerebrospinal fluid leak demonstrated by retrograde myeloscintigraphy.

Cerebrospinal fluid (CSF) leaks may occur following spinal surgery and are commonly associated with infection. These leaks can be successfully evaluated with retrograde myeloscintigraphy using the same techniques applied in diagnosing CSF otorrhea and rhinorrhea. This report describes the utility of this procedure in differentiating a process due solely to postoperative infection from one that involves both an inflammatory site and a fistulous tract with the subarachnoid space.