The Correlation Between Clinical Characteristics and Radionuclide Salivagram Findings in Patients With Brain Lesions: A Preliminary Study

Abstract

Objective: To evaluate the correlation between radionuclide salivagram findings and clinical characteristics in dysphagic patients with brain lesions.

Methods: The medical records of 35 dysphagic patients with brain lesions who simultaneously underwent both a videofluoroscopic swallowing study (VFSS) and radionuclide salivagram were analyzed retrospectively. The subjects were divided into two groups according to the presence of aspiration on a salivagram (group A, patients with aspiration on the salivagram; group B, patients with no aspiration on the salivagram). The differences between clinical characteristics and VFSS findings (penetration-aspiration scale [PAS]) between the two groups were analyzed.

Results: Eleven out of 35 patients displayed salivary aspiration on the radionuclide salivagram. There were no significant differences between the two groups according to age, sex, disease duration, PAS on VFSS and feeding methods (p≥0.05). The incidence of aspiration pneumonia was significantly higher in group A. In a multivariate logistic regression analysis with forward stepwise method, the Mini-Mental State Examination (MMSE) score was the only significant parameter in predicting positive findings in salivagrams (odds ratio=0.760; 95% confidence interval [CI], 0.625-0.923; p=0.006). The area under the receiver operating characteristic curve (AUC) of the MMSE score for positive detection in salivagrams was 0.855 (95% CI, 0.689-0.953; p<0.0001). The optimal cut-off value was 7 for the MMSE score (sensitivity 72.73%, specificity 100%).

Conclusion: In patients with brain lesions who complain of dysphagia, the MMSE score was correlated with salivary aspiration. If patients present with a score of 7 or less on the MMSE, performing a radionuclide salivagram may helpful for early detection of patients at high risk of aspiration pneumonia induced from salivary aspiration.

Keywords: Aspiration pneumonia; Cognition; Deglutition; Sialorrhea; VFSS.

Fig. 1. Flow chart of inclusion and exclusion criteria of the study sample. VFSS, videofluoroscopic swallowing study; MMSE, Mini-Mental State Examination; MBI, Modified Barthel Index.

Fig. 2. Sequential images of the radionuclide salivagram throughout the 1 hour immediately following oral administration of the Tc-99m sulfur colloid solution. (A) The presence of a radiotracer in the trachea and bilateral bronchi is a positive indicator of salivary aspiration (arrows). (B) The uptake of the radiotracer noted only in the oropharynx, esophagus and stomach is a negative indicator of salivary aspiration.

Fig. 3. ROC curve of MMSE score for developing aspiration on the radionuclide salivagram in patients with brain lesions. The optimal cut-off value (dots on the curves) for the MMSE score, which was obtained from the maximal Youden index, was a value of 7 for aspiration on the radionuclide salivagram (AUC=0.855; 95% CI, 0.689–0.953; p<0.0001; sensitivity 72.73%, specificity 100%). ROC, receiver operating characteristic; MMSE, Mini-Mental State Examination; AUC, area under the ROC curve.