Korean J Oral Maxillofac Radiol.  2005 Sep;35(3):157-165.

Evaluation of compression ratios using JPEG 2000 on diagnostic images in dentistry

Affiliations
  • 1Department of Oral and Maxillofacial Radiology, School of Dentistry, Dankook University Hospital. ekkim@dku.edu
  • 2Department of Diagnostic Radiology, Dankook University Hospital.
  • 3Department of Oral and Maxillofacial Radiology, School of Dentistry, Seoul National University.

Abstract

PURPOSE
To find out the proper compression ratios without degrading image quality and affecting lesion detectability on diagnostic images used in dentistry compressed with JPEG 2000 algorithm. MATERIALS AND METHODS: Sixty Digora periapical images, sixty panoramic computed radiographic (CR) images, sixty computed tomographic (CT) images, and sixty magnetic resonance (MR) images were compressed into JPEG 2000 with ratios of 10 levels from 5 : 1 to 50 : 1. To evaluate the lesion detectability, the images were graded with 5 levels (1: definitely absent; 2: probably absent; 3: equivocal; 4: probably present; 5: definitely present), and then receiver operating characteristic analysis was performed using the original image as a gold standard. Also to evaluate subjectively the image quality, the images were graded with 5 levels (1: definitely unacceptable; 2: probably unacceptable; 3: equivocal; 4: probably acceptable; 5: definitely acceptable), and then paired t-test was performed. RESULTS: In Digora, CR panoramic and CT images, compressed images up to ratios of 15 : 1 showed nearly the same lesion detectability as original images, and in MR images, compressed images did up to ratios of 25 : 1. In Digora and CR panoramic images, compressed images up to ratios of 5 : 1 showed little difference between the original and reconstructed images in subjective assessment of image quality. In CT images, compressed images did up to ratios of 10 : 1 and in MR images up to ratios of 15 : 1. CONCLUSION: We considered compression ratios up to 5 : 1 in Digora and CR panoramic images, up to 10 : 1 in CT images, up to 15 : 1 in MR images as clinically applicable compression ratios.

Keyword

Image Compression; Radiography, Dental, Digital; Tomography, X-ray Computed; Magnetic; Resonance Imaging

MeSH Terms

Data Compression
Dentistry*
Radiography, Dental, Digital
ROC Curve
Tomography, X-Ray Computed
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