Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.
Improved Assessment of Parotid Gland Dysfunction with Scintigraphy in Sjgren's Syndrome.
Keyes, Anthony L., Manno, Rebecca L., Mills, Margaret, Petronis, John, Baer, Alan N.
The optimal method for assessing parotid gland function by scintigraphy has been debated. We chose to compare the initial slope of radiotracer uptake by the parotid glands with more conventional measures of net uptake ratio and maximal count time as a means to differentiate patients with Sjogren's syndrome (SS) from sicca control patients.
Parotid scintigraphy was performed on 20 patients as part of their evaluation for suspected or established SS. A diagnosis of SS was assigned to 10 of these patients, based on the 2002 AECC criteria. The results of the parotid scintigraphy were not utilized in this classification. For each patient, the time-activity curve of radiotracer uptake by the parotid glands was assessed by the net uptake ratio (ratio of maximum count and the count at 60 seconds) and the maximal count time (time at which the maximum count was reached). These results were referenced to a prior study which defined the range of values in a group of healthy controls (J Nuc Med 1998; 39:1260). The slopes of the time-activity curves to the point of maximal counts were assessed by linear regression.
The mean slopes of radiotracer uptake were 1.03 ± 0.7 counts/sec and 0.97 ± 0.7 counts/sec respectively for the left and right parotid glands of the SS patients and 3.36 ± 2.7 counts/sec and 3.17 ± 0.98 counts/sec respectively for the left and right parotid glands of the sicca control patients. These differences were statistically significant for the left parotid gland (p=0.023, Student t-test) and trended to significance for the right parotid gland (p=0.0548). A slope value of 1.6 counts/sec best differentiated the two groups. Thus, the initial slope for radiotracer uptake was less than 1.6 counts/sec for 8/10 left parotid and 9/10 right parotid scans of the SS patients and more than 1.6 counts/sec for 8/10 left parotid and 8/10 right parotid scans of the sicca controls. Using a published range of values for normal individuals, the net uptake ratios were more than 2 standard deviations from the norm for 8/10 left parotid and 6/10 right parotid scans in the sicca controls and 10/10 left parotid and 9/10 right parotid scans for the SS patients.
Measurement of the initial slope of radiotracer uptake by the parotid glands provided better differentiation of SS from sicca control patients than assessment of net uptake ratios. This observation suggests that the same slope calculation in a group of healthy controls would yield a more narrow range of normal values for radiotracer uptake in parotid scintigraphy and increase the clinical utility of the test.
To cite this abstract, please use the following information:
Keyes, Anthony L., Manno, Rebecca L., Mills, Margaret, Petronis, John, Baer, Alan N.; Improved Assessment of Parotid Gland Dysfunction with Scintigraphy in Sjgren's Syndrome. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :473