Comparison of the Length of Styloid Process in Panoramic Radiographs to Computed Tomography as the Gold Standard

To compare the length of styloid process assessed using computed tomography (CT) and panoramic radiographs (PAN).

PAN were taken for 15 patients requiring CT reporting to PMS Dental College or metro scans, after obtaining informed consent and fulfilling all the inclusion and exclusion criteria. CT images were taken in metro scans. The apparent lengths of styloid process were measured in both CT and PAN using software provided with the respective machines. Ethical committee approval was obtained from PMS Dental College, Trivandrum.

The length of left styloid process in CT was observed 20-30 mm in 4 (27%) patients and same in PAN was observed in 5 (33%) patients. Out of 15 patients, abnormal styloid process (length >30 mm) was observed in 11 (73%) patients when measured with CT and 10 (67%) patients in PAN. In CT, the length of the styloid process on the right side was observed between 20 and 30 mm, in 3 (20%) patients. PAN of 2 (13%) patients were found between 20 and 30 mm. On the right side, abnormal styloid process (length >30 mm) was noted in 12 (80%) patients using CT and 13 (87%) patients in PAN. The length of styloid process in the combined sample (both right and left side) was found to be between 20 and 30 mm in 3 (10%) patients and styloid process >30 mm long (in both CT and PAN) was observed in 12 (40%) patients.

This study demonstrated positive correlation between CT and panoramic measurements. "P" values were statistically significant on both sides with values of right side (P = 0.01) and left side (P = 0.002), respectively. Hence, PAN, which are routinely taken, cost-effective and involving relatively low radiation dose, may be used as substitute for CT for the purpose of diagnosis of elongated styloid process. However, for precise measurement of the length of styloid process, CT is still the imaging modality of choice.