Validation of quantitative salivary gland scintigraphy in relation to the American-European concensus criteria for Sjögren's syndrome.

PURPOSE: The aim of this retrospective study was to evaluate the diagnostic value of semiquantitative parameters in salivary gland scintigraphy (SGS) in the diagnostic work-up of primary Sjögren's Syndrome (SS) using the American-European consensus criteria (AECC) as the gold standard. PATIENTS AND METHODS: 99mTc-pertechnetate-SGS was performed in 110 patients with suspected primary SS. Uptake ratios (URs) and excretion fractions (EFs) for all parotid and submandibular salivary glands were calculated. Patients were divided into SS-positive, SS-negative, and SS-equivocal groups on the basis of the AECC criteria. SGS semiquantitative parameters were compared per group and cut-off values were defined. RESULTS: Ninety-six (87%) women and 14 (13%) men with a mean age of 51 years (range: 18-77 years) were included. All patients underwent SGS, labial biopsy, Schirmer's test, and antibody tests (anti-SS-A and anti-SS-B). Twenty-four patients were SS positive, 56 patients were SS negative, and 30 patients were SS-equivocal.UR of the parotid glands did not differ between SS-positive and SS-negative groups [mean (range): 3.4 (1.4-6.9) and 3.9 (2.2-6.5), respectively], whereas UR of the submandibular glands were significantly lower in SS-positive patients [mean (range): 2.7 (1.1-5.6) and 3.5 (2.3-5.3), respectively]. EF in both parotid and submandibular glands was significantly lower in SS-positive patients compared with SS-negative patients: parotid 24% (range: -4 to 53%) and 36% (range: 15-58%), respectively; submandibular 16% (range: -5 to 46%) and 29% (range: 9-49%), respectively.On the basis of a cut-off value of 2.0 for UR and 20% for EF, the sensitivity, specificity, positive predictive value, and negative predictive value were 0.67, 0.86, 86, and 67%, respectively. Of 30 SS-equivocal patients, 15 had a positive SGS, whereas the other 15 were SGS negative. In both, there was no correlation with the AECC criteria IV (histopathology) and VI (antibodies). In these cases, the SGS result was decisive. CONCLUSION: Quantitative SGS is a valuable tool in the diagnostic management of patients with suspected primary SS, especially in those in whom the nonscintigraphic AECC criteria are not conclusive. The straightforward quantitative analysis of SGS used in this study can be implemented in any nuclear medicine department.

Imaging of fibrogenesis in patients with idiopathic pulmonary fibrosis with cis-4-[(18)F]-Fluoro-L: -proline PET.

PURPOSE: Idiopathic pulmonary fibrosis (IPF) is a lethal lung disease for which no single diagnostic modality is able to evaluate the activity of the disease process. Cis-4-(18)F-fluoro-L: -proline ((18)F-proline) was shown in animal studies to be a reliable marker for fibrosis formation. We tested this candidate radioligand for imaging of fibrogenesis in patients with IPF. METHODS: Five patients with IPF proven by lung biopsy and computed tomography were included. Furthermore, we also included one patient with non-specific interstitial pneumonia (NSIP) and scleroderma and one with NSIP and organising pneumonia. Positron emission tomography (PET) acquisition was performed 1, 2 and 3h after injection of 400MBq (18)F-proline. We scored (18)F-proline activity visually and quantitatively by calculating the activity in the regions of interest over lung, liver and mediastinum. RESULTS: We found low uptake of (18)F-proline in the lungs of all patients with IPF. The highest uptake was seen at 2h post-injection, with a decline at 3h past injection. The differences in lung uptake between patients were small, except for one patient with NSIP and organising pneumonia who had a slightly higher (18)F-proline uptake. No significant correlations between (18)F-proline uptake and clinical parameters were found. CONCLUSIONS: Due to the low pulmonary uptake of (18)F-proline in patients with IPF, (18)F-proline does not seem to be a suitable radioligand to evaluate the activity of fibrosis formation in patients with IPF. The low uptake in the lungs of patients with interstitial fibrosis may be explained by the slow nature of fibrogenesis or to the relatively low dose of proline that can be used.

The accuracy of 1-day dual-isotope myocardial SPECT in a population with high prevalence of coronary artery disease.

BACKGROUND: In order to evaluate the diagnostic efficacy of the 1-day separate acquisition dual-isotope single-photon emission computed tomography (SPECT) protocol, using 201Tl for the rest and 99mTc-tetrofosmin for the stress images, a consecutive series of patients with suspected or known coronary artery disease (CAD) was studied that also underwent coronary angiography. METHODS: The results of myocardial SPECT, using a semi-quantitative visual analysis, were acquired in 123 patients and compared with the results of coronary angiography. Sensitivity and specificity were calculated, using thresholds of > or = 50 and > or = 70% stenosis. As an alternative for specificity, the normalcy rate was determined in a separate group of 87 patients with a < 5% pre-test likelihood of CAD. RESULTS: The prevalence of CAD using > or =50 and > or = 70% stenosis was 88 and 78%, respectively. The sensitivity for detection of patients with > or = 50 and > or = 70% stenosis was 94 and 97%, respectively while specificity was 62 and 59%, respectively. The high rate of false positive perfusion defects resulting in a low specificity could be explained by specific clinical issues. However, the routine assessment with additional clinical and electrocardiographic data resulted in a correct interpretation of most of the false positive perfusion defects. The positive predictive value was 92 and 85% and the negative predictive value 46 and 77%, using thresholds of > or = 50 and > or = 70% stenosis, respectively. The normalcy rate was 91%. CONCLUSION: The one-day separate acquisition rest 201Tl/stress 99mTc-tetrofosmin SPECT protocol is an efficient procedure for myocardial perfusion scintigraphy with high sensitivity for detection of CAD. Specific clinical issues caused a low value for specificity. Therefore, clinical information and knowledge of the electrocardiogram is essential for a correct interpretation of SPECT images.

Incremental prognostic value of myocardial SPET with dual-isotope rest (201)Tl/stress (99m)Tc-tetrofosmin.

The incremental prognostic value of dual-isotope myocardial perfusion scintigraphy using technetium-99m tetrofosmin for the stress images was evaluated in 597 consecutive patients with known or suspected coronary artery disease. We used semi-quantitative visual analysis with a five-point scoring system and calculated the summed stress score, the summed rest score and the summed difference score. During the 2-year follow-up period, 46 "hard" cardiac events occurred: 16 cardiac deaths and 30 non-fatal myocardial infarctions. Kaplan-Meier analysis demonstrated a favourable prognosis for patients with normal scans as compared with patients with mildly to moderately or severely abnormal scans ( P<0.001). Multivariate analysis demonstrated incremental prognostic information for nuclear variables. A very low rate of hard cardiac events was observed in patients with a low summed stress score. Thus, nuclear variables provide incremental prognostic information and could be used to guide the management process with respect to whether or not to proceed with further invasive procedures.