Technetium-99m sulfur colloid scanning and correlative magnetic resonance imaging in patients with hairy cell leukemia and hypocellular bone marrow biopsies after 2-chlorodeoxyadenosine.

It has been observed that some patients in complete remission (CR) after 2-chlorodeoxyadenosine (2-CdA) for hairy cell leukemia (HCL) have hypocellular bone marrow biopsies despite normal peripheral blood cell counts. This discrepancy between bone marrow cellularity and peripheral blood cell counts suggests the possibility of abnormal sites of hematopoiesis. To determine sites of hematopoiesis, 11 radionuclide scans using technetium-99m (99mTc) sulfur colloid were performed in eight patients. Although no single, pattern was observed on the 99mTc sulfur colloid scans, two of the eight patients, both with virtually aplastic marrows, had multiple areas of increased uptake in the distal appendicular skeleton, suggesting abnormal sites of hematopoiesis. The same two patients had magnetic resonance imaging (MRI), which confirmed the abnormal sites of hematopoiesis.

Clinical significance of anti-At(a).

Ata is a high-frequency red blood cell (RBC) antigen. Anti-At(a) has been reported in rare At(a-) black subjects. We report two cases of anti-At(a). A clinically significant anti-At(a) was found in a 26-year-old black woman with systemic lupus erythematosus. The patient had a transfusion reaction with chills and nausea during a RBC survival study, and 95% of the radiolabeled At(a+) RBCs were destroyed within 3 h. A concurrently performed monocyte monolayer assay was strongly reactive. Anti-At(a) thus can cause rapid hemolysis of transfused RBCs, but At(a-) donor units are extremely scarce in rare donor registries. A second patient at our hospital had anti-At(a) which did not affect her newborn. She also had autoimmune disease, insulin-dependent diabetes mellitus.

The role of cutaneous lymphoscintigraphy in determining regional lymph node drainage of truncal melanomas.

In the absence of clinically positive regional nodes, any value of prophylactic dissection in malignant melanomas depends on accurate preoperative determination of the pathway of lymphatic drainage. We report on the use of noninvasive radionuclide lymphoscintigraphy in the determination of regional patterns of lymph node drainage in patients with melanomas. Ten patients were studied; treatment was altered by test results in 2. Eleven node groups were excised in 7 patients. There have been no metastatic melanomas found in any nodal basins not detected by lymphoscintigraphy 23 to 42 months after operation.

Usefulness of single-photon emission computed tomography of thallium-201 uptake after dipyridamole infusion for detection of coronary artery disease.

The diagnostic performance of single-photon emission computed tomography (SPECT) and planar imaging of thallium-201 uptake for the detection of coronary artery disease (CAD) was compared in 79 patients who underwent both dipyridamole thallium-201 scintigraphy and coronary angiography. Clinical subgroups were assigned by severity of CAD, presence of a prior myocardial infarction and the number of narrowed coronary arteries. The overall detection of CAD was 89% for SPECT and 67% for planar (p less than 0.001). For the anterior vascular territory, sensitivities for SPECT and planar imaging were 69 and 44% (p less than 0.01), respectively; for the posterior vascular territory, sensitivities were 80 and 54% (p less than 0.01). Receiver-operating characteristic analysis, using a 5-point evaluation scale, was performed for the anterior and posterior vascular territories. Receiver-operating characteristic curves generated for SPECT and planar studies demonstrated improved diagnostic performance by SPECT in the anterior vascular territory, but showed similar performance in the posterior territory because of lower SPECT specificity despite higher sensitivity at clinically relevant decision thresholds. In each clinical subgroup of patients, the detection of CAD by SPECT was significantly superior to that by planar imaging, regardless of the severity of stenosis or the number of significantly narrowed coronary arteries, or whether a myocardial infarction was present. Thus, SPECT thallium-201 scintigraphy is an important and necessary clinical tool for detecting CAD after dipyridamole infusion.

Nuclear medicine imaging workstations based on personal computer technology.

The development of personal computer technology has resulted in extremely powerful, inexpensive computers available as consumer items. With the addition of suitable hardware for gamma camera interfacing and image display, such systems can be transformed into fully functional nuclear medicine computers capable of performing all of the acquisition and processing tasks required in a modern radioisotope imaging department. Such an approach to nuclear medicine computerization offers many advantages in terms of flexibility, speed, cost, and expandability.

Radioimmune localization of occult carcinoma.

Patients with a rising serum carcinoembryonic antigen level and no clinical or roentgenographic evidence of recurrent or metastatic cancer present a treatment dilemma. Eleven such patients, 10 with a previously treated colorectal carcinoma and 1 with a previously treated breast carcinoma, received an injection of the anticarcinoembryonic antigen monoclonal antibody ZCE-025 labeled with the radioisotope indium 111. Nuclear scintigraphy was performed on days 3 and 5 through 7 to detect potential sites of tumor recurrence. The monoclonal antibody scan accurately predicted the presence or absence of occult malignancy in 7 (64%) patients. Second-look laparotomy confirmed the monoclonal antibody scan results in the patients with colorectal cancer, and magnetic resonance imaging confirmed metastatic breast cancer. This study demonstrates that In-ZCE-025 can localize occult carcinoma and may assist the surgeon in facilitating the operative exploration. In-ZCE-025 assisted in the initiation of adjuvant therapy for the patient with breast cancer.

Value of post-therapy whole-body I-131 imaging in the evaluation of patients with thyroid carcinoma having undergone high-dose I-131 therapy.

Post-therapy whole-body I-131 images were compared to 5 mCi pretherapy diagnostic studies in 39 cases of well-differentiated thyroid carcinoma treated with I-131 to evaluate the utility of this procedure for the detection of residual thyroid tissue and functioning metastases. The post-therapy studies were performed immediately before hospital discharge, when the patient's whole-body retained dose had just fallen below 30 mCi. The mean therapeutic dose given was 121 mCi, and the mean interval between administration of the therapy dose and imaging was 2.4 days. In 18 cases (46.2%), the post-therapy images demonstrated either additional findings, such as unsuspected cervical node or pulmonary uptake, or more accurate localization of abnormalities seen on the diagnostic study. In 6 additional cases (15.4%), questionable new findings were noted. Although the precise implications of these additional findings are uncertain at present, they may have a significant effect on future patient management and follow-up. Therefore, the authors recommend that post-therapy imaging be included in the post-therapy evaluation of these patients. In addition, these findings would also suggest reevaluation of the advisability of using 1-2 mCi doses of I-131 for diagnostic whole-body imaging.

Stability of radioiodinated monoclonal antibodies: in vitro storage and plasma analysis.

The in vitro stability and immunointegrity of four radioiodinated monoclonal antibodies was evaluated in various storage conditions and also in plasma samples. The monoclonal antibodies studied included T101, B72.3, Lym1, and 16.88. Stabilities of typical monoclonal antibody therapy solutions, with radioactivities ranging from 2220 to 3700 MBq (60-100 mCi) were assessed using conventional instant thin layer chromatography and size exclusion high performance liquid chromatography. Radioimmunoreactivity was assessed using a live cell attenuated cell, or mucin-linked bead assay. Results of the study demonstrated that therapy solutions were stable to degradation, if properly stored in 5 or 10% human serum albumin at 4 degrees C for the duration of the study (5 days). Minor losses in immunoreactivity were also measured in stabilized therapy solutions. When incubated in plasma samples, radioiodinated monoclonal antibodies generally remained stable for the duration of the study (3 days). However, significant decreases in immunoreactivity were measured for specific radioiodinated monoclonal antibody preparations.

A new radioisotope technique of splenic localization for radiation treatment.

A new technique of splenic localization, before initiating radiation therapy in patients with Hodgkin's disease, is described. We find this method of splenic localization economical and accurate.

Considerations for tomographic imaging of monoclonal antibodies.

Monoclonal antibodies have begun to assume a significant role in clinical research. The ability to label these agents has initiated research in the areas of radioimmunodetection and radioimmunotherapy. In the case of antibodies directed against tumor antigens, imaging has been employed to help assess location and extent of disease, and to provide information and extent of disease, and to provide information concerning biodistribution to be used in subsequent dosimetric calculations. Because of the low counting statistics characteristic of such images, the use of single photon emission computed tomography (SPECT) is suggested as a potential method of improving the diagnostic yield from image data. Careful attention to acquisition parameters and image processing options is needed if these goals are to be achieved.

Ventilation-perfusion scintigraphy in suspected pulmonary embolism: correlation with pulmonary angiography and refinement of criteria for interpretation.

Retrospective analysis of 139 ventilation-perfusion (V/Q) lung scans obtained for suspected pulmonary embolism (PE) was undertaken, using the Biello criteria for interpretation. All scans were correlated with chest radiographs obtained within 24 hours and with pulmonary angiograms obtained within 72 hours of the V/Q study. The prevalence of PE in the high-, intermediate-, and low-probability groups was 89.5%, 49.3%, and 3.6%, respectively. Using minor modifications of these criteria, V/Q scans interpreted as high or low probability had a sensitivity of 97.1%, specificity of 94.3%, and accuracy of 95.7%. Perfusion defects corresponding to radiographic abnormalities that were present for at least 10 days were less likely to be associated with PE. Separate analysis of 27 perfusion-only lung scans that met all other criteria for inclusion in the study confirmed the nonspecificity of perfusion-only lung imaging and indicated the need for ventilation imaging with Tc-99m-DTPA aerosol or Kr-81m gas for portable studies.

Radioimmunoimaging of human small cell lung carcinoma with I-131 tumor specific monoclonal antibody.

In this study, an IgM monoclonal antibody (MAb600D11) directed against human small cell lung cancer (NCI-H69) was radiolabeled with iodine-131, and the biodistribution and image quality of the radiolabeled antibody was evaluated. Radiolabeling was achieved in a solid-phase system consisting of 1,3,4,6-tetrachloro-3a,6a-diphenylglycoluril. Labeling efficiencies and protein purification were accomplished using gel exclusion chromatography while radioimmunoreactivity was determined using a solid-phase radioimmunoassay procedure. The biodistribution of I-131-labeled MAbs was determined in Sprague-Dawley rats up to 7 days after injection. Highest organ concentrations were observed in liver (3.91 +/- 0.47 (SD) and 0.17 +/- 0.04 (SD) mean percent injected dose at 1-7 days after injections) and in thyroid (5.33 +/- 0.71 (SD) and 5.32 +/- 2.01 (SD) mean percent injected dose at 1-7 days after injection). Nude mice, bearing either a small cell lung tumor (NCI-H69) or a nonspecific tumor (adenocarcinoma), were injected with 400-800 microCi of I-131 labeled monoclonal antibody. Optimum tumor visualization was observed 2-4 days after injection with tumor concentrations as high as 10.4% of the initial injected dose. The results demonstrated that radioimmunoimaging of human small cell lung carcinoma was feasible with the tumor-specific IgM I-131-labeled MAb.

Estimation of hemopoietic potential by CFU-c and bone marrow scan in cancer patients.

The concentration of granulocyte-macrophage colonies in culture (CFU-c) in bone marrow cells was estimated, and bone marrow radionuclide scans were performed in a group of 15 cancer patients prior to bone marrow harvest for autologous transplantation. Preharvest CFU-c counts on iliac-crest bone marrow aspirates correlated very well with CFU-c counts from fresh and frozen-thawed bone marrows. Technetium-99m-sulfur colloid radionuclide scans showed that the distribution of total-body bone marrow and increased peripheral radionuclide uptake correlated with higher preharvest and harvest CFU-c counts. Bone marrow scan results were available in 1 h, whereas CFU-c counts took 14 days to obtain. Bone marrow scans may facilitate the clinical estimation of hemopoietic activity in patients under consideration for autologous bone marrow transplantation.

Enlarged cerebrospinal fluid spaces in infants with subdural hematomas.

Computed tomography in 16 infants with subdural hematomas showed enlarged basal cisterns, a wide interhemispheric fissure, prominent cortical sulci, and varying degrees of ventricular enlargement. Radionuclide cisternography in eight of the 16 patients showed findings consistent with enlargement of the subarachnoid space rather than those of communicating hydrocephalus. Clinical findings and brief follow-up showed no convincing evidence for cerebral atrophy in 13 patients. These findings suggest that the enlarged subarachnoid space, which is encountered in some infants and may be a developmental variant, predisposes such infants to subdural hematomas.