Biomedical subjects

A T Isitman

Publications and source records attributed to A T Isitman.

67 records · Page 4Linked to original sources

PubMed1985

Detection of femoral head avascular necrosis in adults by SPECT.

Twenty-one adult patients with the clinical diagnosis of avascular necrosis (AVN) of the femoral head were examined with radionuclide angiography, planar bone scintigraphy, and single photon emission computed tomography (SPECT). A final diagnosis of AVN was established for 15 symptomatic patients with a total of 20 involved hips. SPECT and planar bone scintigraphy were considered positive for AVN only if a photopenic bony defect could be identified. Using SPECT bone scintigraphy, 12 of 15 symptomatic patients and 17 of 20 involved hips (sensitivity of 0.85) were correctly identified, whereas with planar imaging only eight of 15 patients and 11 of 20 involved hips were detected. There were no false-positive diagnoses on SPECT or planar bone scintigraphy. In addition, hyperemia in the region of the proximal femoral metaphysis was demonstrated in six of 20 involved hips. It is concluded that by identifying a photopenic defect that is not evident on planar views, SPECT can contribute to the diagnosis of AVN of the femoral head. In addition, metaphyseal hyperemia appears to be a promising new scintigraphic sign of AVN worthy of further investigation.

Adult↗

PubMed1984

Scintigraphic skeletal "doughnut" sign due to giant cell tumor of the fibula.

Although the "doughnut" sign in brain scintigraphy is a well known phenomenon, similar findings have recently been reported in bone scintigraphy in osseous and nonosseous lesions. A skeletal doughnut sign in bone scintigraphy caused by giant cell tumor of the proximal fibula is presented with a brief review of literature.

Adult↗

PubMed1984

Scintigraphic diagnosis of stress-induced incomplete fractures of the proximal tibia.

Incomplete stress fractures of the proximal tibial diaphysis can be diagnosed by bone scintigraphy. The scintigraphic appearance of incomplete rather than complete tibial stress fractures is apparently reported for the first time in this article. With no treatment other than restricted activity, this injury heals rapidly and completely in 4 to 6 weeks. The major threat to the patient's welfare is unfounded suspicion of tumor or infection which may lead to biopsy or inappropriate therapy.

Adolescent↗

PubMed1984

Gamma camera energy windows for Tc-99m bone scintigraphy: effect of asymmetry on contrast resolution. Work in progress.

By raising the lower threshold of the Tc-99m energy window, rejection of scattered photons can be made more efficient. Unfortunately, with most gamma cameras significant nonuniformities are produced when the window is changed to an asymmetric setting. Recently introduced designs with gain stabilization of the photomultiplier tubes and improved energy correction maintain field uniformity even for an asymmetric window. To assess the impact of an asymmetric energy window on clinical images, 33 Tc-99m-MDP scintigrams of the lumbar spine were taken with symmetrical (126-154 keV) and asymmetric windows (135-154 keV). Bone:soft tissue ratios improved with the asymmetric window, and the resulting images were preferred by the physicians questioned.

Abdomen↗

PubMed1984

Concentration of In-111-oxine-labeled autologous leukocytes in noninfected and nonrejecting renal allografts: concise communication.

Autologous leukocytes labeled with In-111 oxine (ILL) concentrated in the renal allografts of eight patients for whom transplant rejection, infection, or acute tubular necrosis (ATN) could be excluded. All patients had good-to-adequate renal function at the time of ILL scintigraphy, and none developed rejection or renal transplant failure during a 1-mo follow-up period. It is concluded that normally functioning renal allografts without evidence of rejection, infection, or ATN often will concentrate ILL. When a baseline study is not available for comparison, this phenomenon limits the value of ILL scintigraphy as a diagnostic test for transplant rejection or infection.

Adult↗

PubMed1983

Internal derangement of the temporomandibular joint: detection by single-photon emission computed tomography. Work in progress.

The diagnostic accuracy of both planar and single-photon emission computed tomography (SPECT) bone scintigraphy, radionuclide angiography, arthrography, and conventional radiography was evaluated in 36 patients with temporomandibular joint (TMJ) dysfunction undergoing preoperative testing. The sensitivity of SPECT bone scintigraphy (0.94) was comparable with arthrography (0.96) and significantly better than planar bone scintigraphy (0.76), radionuclide angiography (0.35), and transcranial lateral radiographs (0.04). While data for a larger asymptomatic control population are needed, preliminary results give SPECT a diagnostic specificity of 0.70 for internal derangements of the TMJ requiring surgical correction. It is concluded that SPECT bone scintigraphy is a useful noninvasive imaging test to screen for internal derangement of the TMJ.

Adolescent↗

PubMed1975

Radionuclide bone images in hypertrophic pulmonary osteoarthropathy.

Hypertrophic Pulmonary Osteoarthropathy (HPO) can be differentiated from osseous metastasis on conventional bone images using technetium 99m radiopharmaceuticals. Periosteal new bone formation appears as symmetric circumferential deposition of radionuclide in the diaphyseal cortex of tubular bones. In contrast, asymmetrical deposits in the medullary canal are indicative of metastatic disease. The etiologies of hypertrophic osteoarthropathy are discussed.

Bone Neoplasms↗

PubMed1975

Enzymatic inhibition of diphosphonate: a proposed mechanism of tissue uptake.

Enzymes have been proposed as tissue receptors that bine 99mTc-stannous diphosphonate and its analogs. Incubation of diphosphonate with several enzymes demonstrated inhibition of acid and alkaline phosphatase activity but showed no effect on glutamic oxalacetic transaminase and lactate dehydrogenase activity. Complete reversal of the diphosphonate-induced inhibition of alkaline phosphatase activity occurred when calcium ion was added to the reaction. The specificity of calcium to induce reversal was dispelled when magnesium ion gave identical results. Diphosphonate-induced inhibition of acid phosphatase, however, was not reversed by calcium or magnesium.

Acid Phosphatase↗

PubMed1974