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R J Cowan

Publications and source records attributed to R J Cowan.

At least 19 recordsLinked to original sources
PubMed1989

False-positive radionuclide hepatobiliary imaging following cystic duct stone removal.

The authors report a case in which a radionuclide hepatobiliary image was falsely indicative of cystic duct obstruction in a patient with an indwelling cholecystostomy tube and an externalized gallbladder-duodenal stent. Cystic duct patency was demonstrated radiographically shortly before and after the radionuclide study. The authors recommend that cystic duct obstruction indicated by a radionuclide hepatobiliary image be confirmed by another means if a cholecystostomy tube is present, or if the patient recently has undergone percutaneous gallbladder or cystic duct manipulations.

Aged↗
PubMed1988

Radioiodide imaging of struma cordis.

This is the first reported case in which struma cordis was demonstrated with radionuclide imaging. A 56-year-old white woman underwent surgical excision of a benign intracardiac thyroid mass (struma cordis). Subsequent radionuclide imaging with I-123 sodium iodide and Tc-99m labeled red blood cells demonstrated a normal cervical thyroid gland as well as a focus of activity in the mediastinum consistent with intracardiac thyroid.

Choristoma↗
PubMed1987

Urinoma detected by dual isotope renogram-cystogram.

A case is reported in which a urinoma developed following a renal transplant. Dual isotope renography-cystography using Tc-99m DTPA and Ga-67 citrate revealed the diagnosis after ultrasonography and radiographic cystography were nondiagnostic.

Cysts↗
PubMed1987

Thyrotoxicosis caused by functioning metastatic thyroid carcinoma. A rare and elusive cause of hyperthyroidism with low radioactive iodine uptake.

A patient with progressively worsening thyrotoxicosis, refractory to medical therapy, is described. Repeated measurements of thyroidal RAI uptake over a 13 month period were low consistently and could not be explained by iodine ingestion, thyroiditis, or administration of exogenous thyroid hormone. An I-131 scan ultimately revealed striking activity at the base of the skull, reflecting ectopic excessive production of thyroid hormone by a solitary functioning metastatic thyroid carcinoma. The thyrotoxic state resolved after large doses of therapeutic I-131. Typical features of this rare cause of hyperthyroidism are discussed.

Adenoma↗
PubMed1987

Relationship of radionuclide liquid bolus transport and esophageal manometry.

Using simultaneous esophageal manometry and radionuclide transit studies, we compared liquid bolus transport with the various parameters of esophageal contractions. Study subjects included seven normal individuals, six patients with the "nutcracker esophagus" (mean distal peristaltic amplitude greater than 180 mm Hg), and three patients with spastic motility disorders. Manometric studies were performed when the subjects were in the basal state and after intravenous administration of edrophonium and atropine. Simultaneous radionuclide studies were done with subjects in the supine position by swallows of 250 mu Ci technetium Tc 99m sulfur colloid in 10 ml water. We found that normal liquid bolus transport (less than 15 seconds) is primarily dependent on the presence of a peristaltic wave front throughout the esophagus. Above a threshold pressure of 30 mm Hg, liquid transport was not affected by amplitude (33 to 500 mm Hg) or duration (3 to 15 seconds) of esophageal contractions. Repetitive wave forms also gave normal transit times as long as the wave front was peristaltic in onset. There was a significant inverse correlation (-0.65; P less than 0.001) between liquid transit time and peristaltic velocity. Prolonged radionuclide transport (30 to less than 50 seconds) was observed only with nonperistaltic contractions and very low amplitude (15 to 30 mm Hg) peristaltic waves.

Atropine↗
PubMed1986

Conventional radionuclide brain imaging in the era of transmission and emission tomography.

The clinical applications for conventional radionuclide brain imaging have declined considerably since the introduction of newer imaging modalities (computerized cranial tomography [CCT], nuclear magnetic resonance [NMR]). Currently, conventional brain imaging primarily serves as a complementary test when CCT is negative or equivocal and strong clinical suspicion remains. Selected areas in which radionuclide imaging may be the preferred modality include evaluation of cerebral perfusion in assessment of brain death, detection of early viral encephalitis, evaluation of major venous sinus patency, external marking for localization of intracranial tumor, and in selected cases of suspected subdural hematoma, brain tumor, and cerebrovascular disease. The concept of conventional radionuclide brain imaging will likely undergo considerable change in the near future as newer radiopharmaceuticals are introduced and wider application is made of single photon emission computerized tomography (SPECT) and positron emission tomography (PET) imaging.

Brain↗
PubMed1986

Hematologic depression following therapy with strontium-89 chloride.

Initial clinical trials using strontium-89 (Sr-89) chloride for the treatment of painful skeletal metastases have observed minimal or no hematological depression secondary to the radiostrontium. A patient with marked bone marrow depression temporally related to the administration of the Sr-89 is reported, and the need for close hematological monitoring is emphasized. Bone marrow tumor replacement may predispose patients to marrow depression from radiostrontium, and such patients should be treated with caution.

Aged↗
PubMed1985

The utility of adrenal scintigraphy in Cushing's syndrome and hyperaldosteronism.

Thirty-three adrenal scintigrams in 30 patients were reviewed to determine the utility of this noninvasive imaging technique. It was found to be very accurate in distinguishing bilateral from unilateral hyperfunction in patients who have clinical and biochemical evidence of adrenal cortical hyperfunction. The technique proved correct in 12 of 12 cases of Cushing's syndrome and 14 of 19 cases of hyperaldosteronism. Specific clinical questions were also answered in three miscellaneous cases.

19-Iodocholesterol↗
PubMed1985

Gastroesophageal scintigraphy: is it a sensitive screening test for gastroesophageal reflux disease?

Dynamic radionuclide imaging potentially offers a convenient, noninvasive technique for detecting gastroesophageal (GE) reflux disease. Initial studies suggested a high degree of sensitivity, although subsequent reports have been less encouraging. We sought to clarify this controversy by assessing the sensitivity of GE scintigraphy in 15 patients with severe esophagitis at endoscopy and 15 health volunteers. After acid loading, scintigraphy was performed in the basal state and after maneuvers (Valsalva, abdominal compression) which provoke GE reflux. Computer analysis permitted calculation of a reflux index for each maneuver. An index greater than 4% was considered a positive test. We found that the mean reflux index for the patients was significantly greater (p less than 0.01) than the healthy volunteers; 4.55 +/- 1.75% versus 0.42 +/- 0.11%, means +/- S.E.M. Only 30% of the patients had a reflux greater than 4%. Using data from our healthy volunteers, we redefined an abnormal reflux index as greater than 1.7%, but that only improved the test sensitivity to 60% and the specificity to 100%. Scintigraphy for reflux is primarily limited by the short duration of imaging. We cannot recommend GE scintigraphy as a useful screening test for reflux.

Adult↗
PubMed1985

Amplification of the antitumor activity of phleomycins and bleomycins in rats and mice by caffeine.

While having no antitumor effect per se, caffeine substantially enhanced the antitumor effects of the phleomycins PLM-CHP and PLM-PEP, and the bleomycins BLM-CHP and Blenoxane in rats carrying Walker 256 carcinosarcoma and/or mice carrying Ehrlich ascites tumor, even at doses of phleomycin and bleomycin below the minimum effective level. Positive but less conclusive results were also obtained with PLM-A4A4G and PLM-G.

Animals↗
PubMed1979

Efficacy of radionuclide scanning in patients with lung cancer.

Ninety-two patients with histologically proved carcinoma of the lung were studied retrospectively to determine the usefulness of liver, brain, and bone imaging in their examination and treatment. Occult metastatic liver disease was observed in two (5.3%) of 38 asymptomatic patients, while four (6.6%) of 58 neurologically intact patients had abnormal brain scans. Eight (13.6%) of 59 asymptomatic patients had metastatic bone disease. Seven (18.4%) of 38 patients with no clinical evidence of metastatic disease to liver, brain, or bone had at least one type of abnormal radionuclide study. More than half (52.5%) of the patients studied had at least one abnormal scan exclusive of symptoms. Radionuclide imaging is a useful procedure in the initial evaluation and subsequent management of lung cancer.

Adult↗
PubMed1979

Serum alkaline phosphatase determination. Value in the staging of advanced breast cancer.

A retrospective study of 146 patients with metastatic disease was undertaken to verify the clinical impression that radionuclide scanning rarely, if ever, discloses hepatic metastases in breast cancer patients with normal serum alkaline phosphatase (AP) levels. Only two of 39 patients with abnormal liver scans had normal AP levels, and we conclude that liver scans are not necessary as a routine screening method for liver metastases when the AP level is normal. In contrast AP levels were not predictive of bone scan results. All patients with a twofold or greater elevation of the AP level had abnormal bone, liver, or bone and liver scans. Routine AP determinations provide accurate staging information, and their proper use can decrease the cost of initial and follow-up examination of patients with breast cancer.

Alkaline Phosphatase↗
PubMed1979

Plasmacytoma simulating meningioma on brain scan.

The flow study and static images of the brain scans of two patients with plasmacytoma of the skull were identical to the pattern most commonly seen with meningioma. There was a prominent blush on dynamic imaging which did not wash out combined with an intense uptake on static views adjacent to a meningeal surface. In patients with known multiple myeloma, the diagnosis of plasmacytoma of the skull or cranial cavity should be considered when this characteristic pattern is seen.

Aged↗
PubMed1979

Radionuclide sinography: diagnosis of lateral sinus thrombosis by dynamic and static brain imaging.

Four patients with lateral sinus thrombosis were studied by radionuclide (RN) dynamic studies and RN static brain scans. Findings included: (a) abrupt termination of RN activity in the midportion of a lateral sinus ("stump sign"); (b) nonvisualization on dynamic, increased visualization on static images ipsilateral to a prominent sinus groove on a plain skull radiograph; and (c) increased activity on static images with nonfilling on angiography. RN demonstration of the "stump sign" is pathognomonic of lateral sinus occlusion; the latter two patterns require radiographic demonstration of an ipsilateral sinus groove or angiography for significance.

Adult↗
PubMed1979

Radionuclide scanning in patients with advanced malignant melanoma.

The results of liver, bone, and brain scans in 84 patients with recurrent or metastatic malignant melanoma were reviewed. The liver scan was initially positive in 18% (14/78) and ultimately in 32% (25/78). Serum alkaline phosphatase and lactic dehydrogenase were elevated in 92%. These patients ultimately developed positive liver scans, while convincing hepatomegaly was noted in only 44%. Bone scans were eventually positive in 33% (16/49), all of whom had pain. Brain scans were positive in 15% (10/65), all of whom had CNS symptoms. In asymptomatic patients, bone and brain scans only rarely disclosed occult lesions.

Bone Neoplasms↗