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Depreotide Scanning in Sarcoidosis: Summary

Depreotide Scanning in Sarcoidosis: SummaryReaders should note that we are not suggesting that 99mTc-DP scintigraphy should be performed in patients with sarcoidosis. This imaging modality may add nothing to the present approach to sarcoidosis. Rather, our purpose was to demonstrate that additional trials are warranted. Beyond sarcoidosis, our findings have implications for the role for 99mTc-DP imaging in the management of suspected pulmonary malignancies. In appropriate clinical settings, nuclear radiologists and pulmonologists should consider that activity seen on 99mTc-DP imaging may represent sarcoidosis rather than cancer. Conversely, in patients with known sarcoidosis who are undergoing evaluation for a potential malignancy, 99mTc-DP imaging does not allow one to conclusively differentiate a superimposed malignant process from the underlying disease state. As such, 99mTc-DP imaging should not be considered an acceptable diagnostic alternative to biopsy. Continue reading

Depreotide Scanning in Sarcoidosis: PET

For extrapulmonary sarcoidosis, 99mTc-DP imaging might prove most useful. There are no standard, accepted approaches to the evaluation of suspected extrapulmonary sarcoidosis. Tl scintigraphy, for example, which has been studied in cardiac sarcoidosis patients, frequently demonstrates heterogeneous cardiac uptake in patients without clinical diseaseA More specifically, Kinney et al noted abnormal Tl cardiac scans in 30% of subjects with sarcoidosis but no suspected cardiac involvement. Similarly, other investigators have reported that positive Tl scintigraphy findings had no prognostic significance because the test was overly sensitive. In our study, although it was very small, 99mTc-DP imaging nonetheless correctly identified all sites of major, clinically significant visceral involvement in sarcoidosis patients. Continue reading

Depreotide Scanning in Sarcoidosis: Granulomatous activity

Depreotide Scanning in Sarcoidosis: Granulomatous activitySomatostatin analogs represent a novel alternative to Ga. In an early report focusing on In-P, this technique detected new sites of granulomatous activity in 9 of 13 patients. In a larger series of 46 individuals with sarcoidosis, Kwekkeboom and colleagues noted that In-P detected known adenopathy and parenchymal involvement in 97% of cases. In-P identified new sites of sarcoidosis activity in 50% of subjects. On repeat scanning, In-P activity diminished in each of these trials among the patients treated with corticosteroids. In-P imaging also appears to be more accurate than Ga imaging.’ Lebtahi et al compared Ga imaging to In-P imaging in 18 persons with sarcoidosis. Although Ga imaging localized to two thirds of the clinically involved sites, In-P imaging detected 83% of areas of clinical sarcoid activity. One concern with In-P imaging is its limited ability to locate extrapulmonary sarcoidosis. For example, in the trial conducted by Lebtahi et al,In-P imaging failed to reveal several known cases of neurosarcoidosis and, overall, missed approximately 40% of all extrathoracic lesions. Technical factors also limit the utility of In-P scintigraphy in that patients must return for repeat image acquisition 24 h after initial injection. Continue reading

Depreotide Scanning in Sarcoidosis: Discussion

Four subjects had known extrapulmonary sarcoidosis (cardiac, two subjects; neurologic, one subject; skin, one subject). An example of cardiac involvement is shown in Figure 3. In the three noncutane-ous cases, 99mTc-DP scanning revealed intense uptake in the involved organs. There was no evidence of extrapulmonary activity in the remaining patients, all of whom lacked clinical evidence of extrapulmo-nary sarcoidosis.
This prospective pilot study demonstrates that 99mTc-DP scans are frequently positive in patients with sarcoidosis. Sites of 99mTc-DP uptake correlate closely with the results of both CXRs and PFTs. 99mTc-DP scans also appear to identify sites of extrapulmonary involvement in patients with sarcoidosis. Continue reading

Depreotide Scanning in Sarcoidosis: ACE level

Depreotide Scanning in Sarcoidosis: ACE levelThere was a strong correlation between the stage determined by CXR and that determined by 99mTc-DP scan. Based on the stage determined by the CXR obtained when the subject initially received a diagnosis, the interstudy agreement was high (к = 0.79; p = 0.0005). There was perfect concordance in 17 subjects (77.3%) as to the stage determined by both CXR and 99mTc-DP scan. When restricted to patients who had abnormal CXR findings at the time of 99mTc-DP image acquisition, the interstudy agreement was stronger (к = 0.94; p = 0.0001). In this instance, 99mTc-DP scanning “mis-staged” only one subject and revealed activity in the lung parenchyma when the lung fields were seen as being clear on the CXR. Comparing the CXRs that had been performed contemporaneously with the nuclear scans (as opposed to ones performed at the time of the initial diagnosis) to the 99mTc-DP scan results revealed an overall agreement in 95.5% of subjects. Continue reading

Depreotide Scanning in Sarcoidosis: Statistical Analysis

We compared the correlation between stage as determined by CXR and that determined by 99mTc-DP scanning with the к statistic. A к statistic of > 0.8 is considered to represent strong agreement. Continuous data are reported as the mean ± SD. We utilized the Student t test to analyze continuous variables. The x2 test was employed to compare categoric variables except in cases in which the expected values were small. In these instances, we relied on the Fisher exact test. All tests were two-tailed, and a p value of < 0.05 was assumed to represent statistical significance. Ninety-five percent CIs are reported where appropriate. Analyses were done using a statistical software package (SPSS, version 10.0; SPSS; Chicago, IL).  Continue reading

Depreotide Scanning in Sarcoidosis: 99mTc-DP Scanning

Depreotide Scanning in Sarcoidosis: 99mTc-DP ScanningAll patients also underwent a CXR prior to 99mTc-DP scanning. The PFT results and Dlco values were interpreted in accordance with the guidelines of the American Thoracic Society. Normal values were derived from Crapo et al, and corrections for race were made. The Dlco was further corrected for hemoglobin. Values for PFTs and Dlco were considered to be abnormal if they fell outside the 95% confidence interval (CI) for the predicted values. We measured the erythrocyte sedimentation rate and the angiotensin-converting enzyme (ACE) level. We recorded current and prior therapy for sarcoidosis and the presence of extrapulmonary sarcoidosis. Extrapulmonary sarcoidosis was defined based on the classifications used by A Case Control Epidemiology Study of Sarcoidosis study group. Continue reading

Depreotide Scanning in Sarcoidosis: Materials and Methods

We hypothesized that, because of the presence of somatostatin receptors on sarcoid granulomas, 99mTc-DP findings would frequently be positive in patients with sarcoidosis. We also speculated that 99mTc-DP would identify sites of extrapulmonary sarcoidosis. Moreover, there are no systematic data to help determine whether management trials utilizing 9 mTc-DP should be performed in sarcoidosis patients. Therefore, we conducted a prospective prevalence trial of 99mTc-DP scanning in sarcoidosis. Continue reading

Depreotide Scanning in Sarcoidosis

Depreotide Scanning in SarcoidosisThe substance 99mTc-labeled depreotide (DP) is a novel radiopharmaceutical that binds to somatostatin receptors. Somatostatin-based nuclear scintigraphy was initially utilized in the evaluation of neuroendocrine tumors. Somatostatin receptors, however, also are overexpressed in other malignant and inflammatory conditions. With nuclear imaging techniques, 99mTc-DP represents a tool for evaluating pulmonary nodules in order to gauge the probability that the lesion is malignant. Currently, 99mTc-DP scanning is formally approved for use in this setting and is reported to have a sensitivity of 95% and a specificity of 85%. http://www.medicine-against-diabetes.net/ Continue reading