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Slice Thickness in the Assessment of Medial and Lateral Tibial Cartilage Volume and Accuracy for the Measurement of Change in a Longitudinal Study
FLAVIA CICUTTINI, KEVIN F. MORRIS, MICHAEL GLISSON, ANITA E. WLUKA
ABSTRACT. Methods. A total of 123 subjects with osteoarthritis had baseline and followup MRI on their symptomatic knee at 2 years. Medial and lateral tibial cartilage volumes were calculated using increasing slice thickness by extracting each second, third, fourth, or fifth slice area to calculate total volume, which was compared to the "gold standard" volume calculated from the original 1.5 mm slices. Results. There was little difference in the average medial and lateral tibial cartilage volume observed as the slice thickness increased from 1.5 to 7.5 mm; medial tibial cartilage volume ranged from 1750 µl to 1787 µl and lateral tibial cartilage volume ranged from 1949 µl to 2007 µl. There was also little absolute difference in the average change in medial and lateral tibial cartilage volume measured over 2 years. However, with increasing slice thickness, there was a decreased correlation between the tibial cartilage volume change calculated from the increased slice thickness, with the lowest correlation being 0.77 (p < 0.001) when the lateral cartilage volume calculated from the 7.5 mm slice was compared to the 1.5 mm slices. Conclusion. Increasing slice thickness may provide sufficiently accurate measurement of tibial cartilage volume and change over time in some studies. This would result in reduction in MRI scanning and postimaging processing time, which has the potential of increasing the feasibility of this technique. (J Rheumatol 2004;31:2444-8) Key Indexing Terms:
KNEE CARTILAGE
From the Department of Epidemiology and Preventive Medicine, Monash University, Alfred Hospital, Prahran, Victoria; and the Centre for Clinical Neuroscience and Neurological Research, St. Vincent's Hospital, Melbourne, Australia. Supported by the Center for Clinical Research Excellence (Therapeutics) and the National Health and Medical Research Council of Australia. F. Cicuttini, FRACP, PhD, Associate Professor; M. Glisson, PhD Scholar; A.E. Wluka, FRACP, NHMRC Scholar, Department of Epidemiology and Preventive Medicine, Monash University; K.F. Morris, ME, FIEAust, Senior Researcher, Centre for Clinical Neuroscience and Neurological Research, St. Vincent's Hospital. Address reprint requests to Dr. F. Cicuttini, Department of Epidemiology and Preventive Medicine, Alfred Hospital, Prahran, Victoria 3181, Australia. E-mail: flavia.cicuttini@med.monash.edu.au Submitted November 18, 2003; revision accepted July 12, 2004. |