A modified Lund-Mackay system for radiological evaluation of chronic rhinosinusitis

The Lund-Mackay system (L-M system) is widely used for computed tomography (CT) evaluation of chronic rhinosinusitis (CRS). However, a major drawback of the L-M system is its insufficiency of gradation. To avoid this deficiency, a new staging system proposed by American societies and the Zinreich system were reported as modifications of the L-M system. The aim of this study was to investigate the efficiency of gradation and the accuracy of the visual quantification of these modified staging systems.

Preoperative CT scanning was performed on 20 adult patients with CRS. A computer workstation was used to measure the volume of each sinus and the volume of inflammatory disease in each sinus. Then the soft tissue density rate (STDR) and objective scores, which were adapted to each system, were calculated. Visual evaluation of the CT images was performed using these systems. The visual score with each staging system and STDR value were evaluated for a correlation, and the rate of agreement was determined between the visual and objective scores obtained with each staging system.

The correlation between the visual scores and the STDR values was shown with all staging system including L-M system. The coefficients of correlation between the visual scores and the STDR values with these modified systems were higher than with the L-M system. While the agreement rates with these modified systems were significantly lower than with the L-M system, differences of 2 or greater between the subjective and objective scores were rare.

We cannot conclude that one of these three staging systems is superior to the other. With this study, the simple grading system such L-M staging score was considered easy and accurate method to use the clinical level. The modified staging systems showed more efficient ability to gradate in evaluating rhinosinusitis inflammation compared with the L-M system and also showed acceptable accuracy.