Role of Ga-67 citrate imaging in extrapulmonary pneumocystis in HIV positive patients.
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Biomedical subjects
Publications and source records attributed to M J Blend.
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In this study, the clinical usefulness of 111In-SCN-Bz-diethylenetriaminepentaacetic acid (DTPA) monoclonal antibody (MoAb) B72.3 in patients with recurrent colorectal carcinoma was evaluated. In previous studies with radiolabelled MoAb B72.3, metastatic liver lesions in patients with colon cancer appeared as areas of either increased (hot lesions) or decreased (cold lesions) activity, and extrahepatic lesions appeared as areas of increased activity. Eleven patients were enrolled in this study, and 12 MoAb imaging study results were correlated with computed tomography/magnetic resonance imaging findings. The improved detection rates (number of hot lesions) in MoAb imaging were 48% (14/29) for hepatic metastases and 60% (6/10) for extrahepatic metastases. This represents a significant improvement in the rate of detection of metastatic disease of the liver in patients with recurrent colon cancer when compared to the rate in previous reports. Seventeen clinically unsuspected hepatic and extrahepatic areas of increased uptake were also identified on MoAb studies, and two of these areas were confirmed as metastatic disease at surgery. The rate of detection of extrahepatic metastases with 111In-SCN-Bz-DTPA MoAb B72.3 was also compared and found to be equal to the detection rates with other radiolabelled immunoconjugates. No major adverse side effects were noted during the administration of the MoAb. Four of nine patients tested had a positive anti-mouse antibody (HAMA) response 3 months after injection. These preliminary data indicate that this 111In-labelled immunoconjugate of MoAb B72.3 demonstrates an improvement in hepatic lesion detection rate than did previously reported preparations in patients with recurrent colon cancer.
The increasing use of monoclonal antibodies (MAbs) for disease diagnosis and therapy has created a class of patients at risk for systematic error in clinical testing due to interference by human anti-murine antibodies (HAMA). HAMA interference is often difficult to detect and can cause either an increase or a decrease in apparent concentrations of antigen present. We undertook a clinical study to test a HAMA-resistant enzyme immunoassay (EIA) format for carcinoembryonic antigen (CEA) determination. Using the Food and Drug Administration-approved CEA-EIA Monoclonal One-Step Assay (Abbott) with the addition of an acid/heat extraction of patients' specimens, we found that the resulting CEA values accurately reflected the patients' status. We demonstrated that the acid/heat-extracted specimens yield linear dilution curves and show analytical recoveries of added CEA in the range of 76-123% in HAMA-positive specimens and 86-103% in HAMA-negative specimens. The correlation of CEA values in extracted vs unextracted specimens from 184 patients and control subjects was 0.9963. The CEA detection limit of the assay was 1.6 micrograms/L for the extracted samples.
The usefulness of radioimmunoscintigraphy with In-111 labeled MoAb B72.3 is illustrated in this case report of a patient with an aggressive cancer of the ascending colon. When used in conjunction with CT, ultrasound examination, and MRI, radioimmunoscintigraphy improved the specificity of these other imaging modalities, although the patient's serum CEA and TAG-72 levels remained within the normal ranges. In addition, MoAb imaging demonstrated superiority over CT in identifying an additional unsuspected lesion. Detection of occult disease by imaging modalities with or without elevated serum CEA levels is discussed.
PURPOSE: A study was performed to assess the usefulness of a radiolabeled monoclonal antibody (MoAb; technetium 99m NR-ML-05 Fab) as a detecting agent, as well as to evaluate its role in the overall decision-making process in the management of cutaneous malignant melanoma. PATIENTS AND METHODS: Twelve patients with histologically confirmed primary cutaneous melanoma and palpable regional nodes were injected with MoAb NR-ML-05 Fab, radiolabeled with 20 to 30 mCi of 99mTc. Whole-body anterior and posterior images were obtained. Left and right lateral views of the head and anterior and posterior views of the chest, abdomen, pelvis, and extremities were obtained, as were selected single-photon emission computed tomographic (SPECT) views of regional lymph nodes and areas of known or suspected lesions. RESULTS: In nine of 12 patients, clinical and/or MoAb evolution identified 30 discrete sites of suspected melanoma. The remaining three patients showed no positive sites, and there was no evidence of metastatic melanoma. All 30 sites were examined microscopically, and melanoma was confirmed histologically in 23. The remaining seven were negative. MoAb imaging detected 21 (true-positive) but failed to detect two (false-negative) lesions. Sensitivity was 91% (21 of 23); positive predictive value was 95% (21 to 22). CONCLUSIONS: MoAb imaging seems to provide an excellent way to obtain information with regard to the metastatic status of melanoma patients. Immunocytochemistry showed that MoAb (NR-ML-05) is as sensitive as the S-100 antibody and probably more sensitive than the commercially available antimelanoma antibody HMB-45.
Avascular necrosis of the hip is a serious clinical problem encountered by primary care physicians. It requires early detection for proper management and treatment. The clinician should be aware of the imaging modalities available for evaluation of patients with suspected avascular necrosis. Traditional studies include plain-film radiography, computed tomography, and planar bone scintigraphy. Magnetic resonance imaging and single-photon emission computed tomography bone scanning have been developed to such an extent that they are now the most sensitive indicators of early avascular necrosis. The authors review currently available imaging modalities and provide a practical approach to the assessment of patients with suspected avascular necrosis of the hip.
A group of 16 sarcoma patients with suspected advanced disease were studied with a radiolabeled anti-sarcoma monoclonal antibody (mAb 19-24) in an attempt to localize tumor deposits. All 16 patients received 125I-mAb 19-24 and then had external-probe analysis and imaging performed. Confirmation of tumor deposits was done at surgery or by autopsy. Tissues were studied in surgical patients when possible and analyzed for radioactivity, and tumor-to-blood ratios ranged from 0.6 to 36.8. In conjunction with the patients previously studied, probe results had an overall sensitivity of 83.3% and an overall specificity of 100%; scintigraphic results showed an overall sensitivity of 78.9% and an overall specificity of 100%. Radiolabeled mAb 19-24 may be developed into a useful tool for clinical immunodetection of sarcoma deposits.
Ischemic colitis is a relatively common clinical entity. Conservative medical management is successful for most patients, but surgical intervention is required for patients with intractable disease. Noninvasive determination of the site and extent of the disease can be helpful in the preoperative decision on the surgical approach in these debilitated patients. However, current radiologic studies individually are inadequate in this respect. Based on the clinicopathologic correlation obtained after imaging with In-111 labeled leukocytes in a patient with ischemic colitis, the authors believe that this procedure may be useful; further studies in a larger patient population are warranted.
A 17-year-old girl presented with right upper quadrant pain and was found to have a subhepatic cyst by ultrasound and CT. A DISIDA scan showed prompt filling of both the gallbladder and a very dilated common bile duct consistent with a choledochal cyst. Following intravenous administration of cholecystokinin, there was immediate emptying of the gallbladder into the cyst. Quantitative cholecystokinin cholescintigraphy may be a useful adjunct in the differentiation of choledochal cyst from gallbladder activity.
Although the full potential of MoAb imaging has yet to be realized, technologic advances continue with great intensity at a number of academic and industrial research institutions. Continuous production of MoAbs will eventually yield a variety of highly specific antibodies and novel approaches for improving cancer detection. As new diagnostic and therapeutic methods continue to be developed, MoAbs will begin to play a major role as targeted carriers, provided adequate funding from industry and government can be readily obtained. At present, the future of monoclonal antibodies in diagnosis and therapy for cancer patients appears promising.
A 35-year-old man was diagnosed in 1984 as having a synovial cell sarcoma of his right wrist without evidence of metastatic spread. The patient underwent regional hyperthermic chemoperfusion, wide-field excision, post-operative radiation therapy and systemic adjuvant chemotherapy. In 1986 and in 1987, because of new lesions found on chest radiographs, the patient underwent bilateral staging thoracotomies with resection of pulmonary metastases, followed by chemotherapy and radiotherapy. Later in 1987, a chest radiograph showed a large left hilar mass and multiple bilateral pulmonary nodules. Computerized tomography of the chest demonstrated a left hilar mass and two nodules in the right lower lung, raising the possibility of recurrent pulmonary metastatic cancer. As a diagnostic procedure, In-111 labeled monoclonal antibody (Mab) 19-24, produced against a human malignant fibrous histiocytoma, was infused intravenously, and 48-hour images revealed focal areas of increased uptake corresponding to the lesions seen on CT. At surgery, the lesions were confirmed to be synovial cell sarcoma. Imaging with Mabs specific for sarcoma may be particularly useful in sarcoma patients in whom there is clinical uncertainty regarding the nature of pulmonary lesions. In this case, the Mab was useful in distinguishing tumor deposits from postsurgical scarring and helped to guide subsequent surgery and treatment.
A technetium-labeled monoclonal antibody was administered to 52 patients with non-small cell lung carcinoma, either to stage the mediastinum preoperatively or to detect distant metastases. Results from planar and tomographic imaging are compared to CT and histologic confirmation. Differences in detection rates and predictive values between imaging modalities are discussed. The authors conclude that imaging with a technetium-labeled monoclonal antibody is safe and accurate and may be useful for staging patients with either operable or inoperable non-small cell lung cancer.
In order to study localization of metastatic tumors with a radiolabeled monoclonal antibody, a pulmonary metastases model was devised in athymic mice. Metastatic pulmonary sarcoma colonies were verified by histological examination. A murine monoclonal antibody (MAb 19-24) directed against a human sarcoma antigen was labeled with indium-111 (111In) by use of the linker 1-(p-isothiocyanatobenzyl)-diethylenetriaminepentaacetic acid (SCN-Bz-DTPA). MAb P3 was similarly labeled as a negative control. In the group given MAb 19-24, the percent injected dose per gram lung tissue bearing tumor colonies (30.1%, 29.6%, and 27.7% on Days 1, 2, and 3, respectively) was significantly (p less than 0.05) higher than in those receiving MAb P3. Hepatic activities of both 111In-MAb 19-24 and 111In-MAb P3 were low. The lungs with tumor colonies demonstrated clearest images on Day 3. The specific binding of 111In-SCN-Bz-DTPA-labeled MAb 19-24 to pulmonary xenografts without appreciable liver uptake indicates that it may be useful in the clinical localization of pulmonic metastatic lesions.
Primary hyperparathyroidism, although often silent clinically, may lead to significant morbidity if it remains untreated. In more than 95% of all cases the cause is a parathyroid adenoma or glandular hyperplasia. Regression of disease follows successful surgical excision of the abnormal parathyroid gland. Recurrent or persistent hyperparathyroidism is most commonly caused by solitary adenomas, which may have an ectopic location. Preoperative localization of lesions may improve postoperative cure rates and decrease morbidity. Thallium T1 201 chloride-technetium Tc 99m pertechnetate subtraction scintigraphy was performed on 15 patients with primary hyperparathyroidism. The sensitivity and specificity for detection of abnormal glands were 90% and 95%, respectively. False-positive or false-negative results were minimize by strict adherence to a protocol and by the use of well-defined diagnostic criteria. Because of the superior sensitivity and specificity, this modality should be the primary imaging method of choice for preoperative evaluation of primary hyperparathyroidism. The relative role of other imaging modalities is also discussed.
Previous studies have indicated that the combination of single photon emission computed tomography (SPECT) and quantitative "bull's eye" analysis (QBA) TI-201 cardiac stress imaging may improve the detection of myocardial ischemia over that achieved with planar (PLN) imaging. This study will evaluate the sensitivity and specificity of SPECT and QBA in the detection of disease in the left anterior descending (LAD), left circumflex (LCX), and right coronary artery. Ninety-nine patients who underwent both TI-201 stress imaging and coronary arteriography were evaluated retrospectively. Of the 99, 62 had PLN imaging and 37 were evaluated with SPECT; 23 of these 37 had QBA. The overall sensitivity and specificity were as follows: PLN, 94% and 50%; SPECT, 90% and 67%; QBA, 100% and 20%; and SPECT with QBA, 92% and 72%, respectively. The regional sensitivity and specificity of PLN for individual coronary arteries were as follows: RCA, 78% and 74%; LAD, 89% and 60%; LCX, 50% and 89%, respectively. For SPECT, the results were: RCA, 86% and 93%; LAD, 85% and 88%; and LCX, 60% and 88%. For QBA alone, the results were: RCA, 100% and 75%; LAD, 88% and 53%; and LCX, 100% and 89%. The results for QBA with SPECT were: RCA, 100% and 94%; LAD, 88% and 80%; and LCX, 67% and 95%. Thus, SPECT interpreted on conjunction with QBA showed higher sensitivity for evaluation of ischemia in the RCA and LCX arteries and higher specificity in the detection of LAD and RCA disease than did PLN TI-201 imaging. Because of the low specificity of QBA (20%), caution is advised in the interpretation of QBA alone without reviewing SPECT images.
A 6-year-old female with an anomalous left coronary artery (ALCA) originating from the main pulmonary artery underwent a resting Tl-201 SPECT examination before and after surgical reimplantation. Preoperative Tl-201 SPECT images demonstrated decreased perfusion to the anterior wall and a dilated left ventricle. Post operative Tl-201 SPECT images showed marked improvement of perfusion to the anterior wall as well as a decreased left ventricular size. This is one of the few documented demonstrations of a perfusion defect due to an ALCA in a young child using Tl-201 SPECT imaging methods in conjunction with other tests.
A murine monoclonal antibody (MoAb 19-24) directed against a human sarcoma antigen was prepared and labeled with 111In by use of the linker 1-(p-isothiocyanatobenzyl)-diethylenetriaminepentaacetic acid (SCN-Bz-DTPA). Imaging and biodistribution of this radioimmunocomplex were evaluated. MoAb P3 was similarly labeled as a negative control. Of 24 athymic mice bearing s.c. human fibrosarcoma, 12 received 10 microCi of [111In]MoAb 19-24 and 12 received 10 microCi of [111In]MoAb P3. The mice were imaged at 24, 48, 68, or 168 hr, after i.p. injection. Region of interest and biodistribution analysis showed maximum localization of MoAb 19-24 in the tumor at 72 hr with maximum liver localization of 24 hr. Analysis of MoAb P3 showed maximum tumor and liver activity at 24 hr. Tumor specificity studies were also conducted in three nude mice bearing a sarcoma in the left flank and a Burkitt's lymphoma in the right flank. Selective uptake was seen in the sarcoma but not in the lymphoma. The excellent uptake of [111In]SCN-Bz-DTPA-MoAb 19-24 in sarcoma without appreciable liver activity indicates that it may be a useful tumor imaging agent in man.
Thallium 201 myocardial perfusion imaging is a standard method of evaluating regional myocardial blood flow. Myocardial perfusion is best evaluated at rest and during exercise, however, alternative methods have been sought to increase coronary blood flow in patients incapable of performing adequate exercise. A promising new method is the use of intravenous dipyridamole for pharmacologic stress imaging. It has distinct advantages over traditional treadmill exercise testing. The primary advantage of combining intravenous dipyridamole and thallium 201 is for testing patients in whom exercise is impractical or contraindicated. Examples include patients taking beta blockers and those who have had myocardial infarction or have severe peripheral vascular disease. To date, this agent has been available only to clinical investigators in approved protocols. With continued success, it should be approved for general use in the near future.