The purpose of this study was to validate the usefulness of SPECT/CT as an evaluation method for determining treatment and prognosis for patellofemoral cartilage lesions, based on MRI and arthroscopic findings. From August 2009 to February 2010, SPECT/CT was performed on 80 patients (24 male and 56 female, average 53.3 years old) with chronic anterior knee pain who had no degenerative changes or patellar malalignment on plain radiographs. Radioisotope uptake findings on patellofemoral joint from SPECT/CT were classified into three grades by one nuclear medicine specialist. In the patients who demonstrated poor improvements after conservative treatments, MRI and arthroscopy were performed. Patellofemoral cartilage conditions under arthroscopic finding (ICRS grades) were compared with SPECT/CT grading. In all cases, there were increased uptakes on patellofemoral joints. Eighteen cases showed low uptake (Group 1), 22 cases showed medium uptake (Group 2) and 40 cases high uptake (Group 3). At the follow-up examination after mean 1.7 months, 16 cases of Group 1 (89%), 14 cases of Group 2 (64%) and 28 cases of Groups3 (70%) responded positively to the conservative treatments. For those 22 cases showing poor improvement, MRI and arthroscopy were done. Damage or thinning of patellofemoral cartilage, subchondral cyst, edema and fissuring were observed in every case that underwent MRI. Every arthroscopic case was found that there was patellofemoral cartilage damage. Each of ICRS grade I and grade II was found in 2 cases from Group 1. Two cases of grade II, 4 cases of grade III, and 2 cases of grade IV were found in Group 2. Two cases of grade II, 4 cases of grade III, and 6 cases of grade IV were found in Group 3. There was significant difference in the success rate of conservative treatment between SPECT/CT grade 1 and 2 or 3. And there was significant association between SPECT/CT grade and ICRS grade (P=0.034). SPECT/CT could be a useful modality in determining the treatment and prognosis for patellofemoral cartilage lesions compared with MRI and arthroscopic findings.
