Magnetic Resonance Imaging (MRI) of the Left Knee without Intravenous Contrast TECHNIQUE: Multi-planar, multi-sequence MR imaging of the left knee was performed on a high-field scanner without the administration of intravenous contrast. Sequences include Coronal (T1, PD fat-sat), Sagittal (T1, T2, PD fat-sat), and Axial (PD fat-sat). FINDINGS: Patellofemoral Joint and Extensor Mechanism: A well-defined focal osseous lesion is identified within the subchondral region of the medial articular facet of the patella, measuring approximately 13 x 10 x 9 mm (AP x TR x CC). The lesion demonstrates low signal intensity on T1-weighted images and predominantly low signal on T2-weighted images, with faint central and punctate foci of high T2 signal, characteristic of a chondroid matrix. On PD-weighted sequences, the lesion remains predominantly low signal with a subtle high-signal rim/margin likely representing subtle reactive subchondral bone marrow edema. The distal quadriceps tendon, patellar tendon, and medial/lateral patellar retinacula are intact. Menisci: • Medial Meniscus: There is linear, horizontal intrasubstance signal alteration within the posterior horn that does not unequivocally intersect the superior or inferior articular surfaces, consistent with mucinoid/myxoid degeneration (Grade II signal). No definite tear. • Lateral Meniscus: Mild thinning and stretching of the anterior horn is noted. No abnormal signal reaching the articular surface to suggest a meniscal tear. Ligaments: • Cruciate Ligaments: The anterior cruciate ligament (ACL) demonstrates mild intrasubstance signal alteration with preserved fiber continuity and normal orientation, suggestive of a low-grade sprain or mucoid degeneration. • The posterior cruciate ligament (PCL) is intact and maintains a normal dark signal and contour. • Collateral Ligaments: The medial collateral ligament (MCL) and lateral collateral ligament (LCL) complexes are intact and unremarkable. Joint Space and Soft Tissues: There is a mild knee joint effusion extending into the posteromedial capsular recess. No evidence of a popliteal (Baker's) cyst. Hoffa's fat pad is unremarkable. Bones and Articular Cartilage: Aside from the previously described patellar lesion, the remainder of the visualized regional bone marrow signal is preserved. No acute fracture or other focal osseous lesions are identified. The tibiofemoral articular cartilage is grossly maintained. IMPRESSION: 1. Focal Patellar Lesion: A 13 x 10 x 9 mm well-defined subchondral osseous lesion at the medial articular facet of the patella demonstrating features of a chondroid matrix with subtle surrounding reactive bone marrow edema. 2. Cruciate Ligaments: Mild intrasubstance signal within an intact ACL, representing a low-grade sprain or mucoid degeneration. 3. Menisci: Intrasubstance mucinoid degeneration (Grade II signal) of the posterior horn of the medial meniscus. No definite meniscal tear. 4. Joint: Mild left knee joint effusion. DIFFERENTIAL DIAGNOSIS: � Enchondroma with mechanical stress � Chondroblastoma � Osteochondral Lesion. Give a Treatment therapy briefly according to this report

IMPRESSION: 1. Focal Patellar Lesion: A 13 x 10 x 9 mm well-defined subchondral osseous lesion at the medial articular facet of the patella demonstrating features of a chondroid matrix with subtle surrounding reactive bone marrow edema. 2. Cruciate Ligaments: Mild intrasubstance signal within an intact ACL, representing a low-grade sprain or mucoid degeneration. 3. Menisci: Intrasubstance mucinoid degeneration (Grade II signal) of the posterior horn of the medial meniscus. No definite meniscal tear. 4. Joint: Mild left knee joint effusion. DIFFERENTIAL DIAGNOSIS: � Enchondroma with mechanical stress � Chondroblastoma � Osteochondral Lesion. This report is 30 years old male left knee MRI without contrast