SPECT BONE-SCINTIGRAPHY OF ANTERIOR CRUCIATE LIGAMENT INJURY

This retrospective analysis of SPECT bone scans of the knee was undert aken to define typical bone scan appearances and to assess the sensiti vity of this method, We looked at 14 patients, mostly with chronic kne e pain, who had anterior cruciate ligament (ACL) tears detected by MRI , Method: Of the 14 patients, 10 were referred for bone scanning follo wing injury and 4 complained of chronic knee pain without injury, Plan ar scans were performed 4 hr after the injection of 750 MBq of (TC)-T- 99m-MDP, Tomographic images were obtained by a 64 x 20-sec acquisition over 360 degrees using a high-resolution collimator, MRI imaging incl uded axial and sagittal, T1 weighted and coronal fast field echo (FFE) sequences, Ten patients also had arthroscopy performed, Results: MRI scans showed 6 lone ACL tears and 8 combined with other ligamentous in juries. SPECT scans showed abnormalities in 10 patients in the region of ACL insertions but only 4 planar studies were abnormal, SPECT ident ified focal activity at the upper(n = 8) or lower(n = 2) insertion of the ACL, Six of 10 arthroscopies confirmed ACL tears, 2 complete and 4 partial, Overall, agreement was found with MRI in 10 of 14 cases and in 8 of 10 with arthroscopy, Abnormalities were identified in 10 of 11 regions of other ligament or bone injury identified by MRI, Conclusio n: SPECT bone scanning of the knee is superior to planar imaging in de tecting ACL injury and is a sensitive technique, Focal activity may be seen at either end of ACL attachment but more commonly at the upper f emoral insertion, Knee SPECT may be a valuable examination in suspecte d ACL injury, particularly if MRI is not available, is equivocal or wh ere clinical signs are absent.