Sports Health Orthopaedic Magnetic Resonance Challenge

In this case, the diagnosis is admittedly challenging when based on coronal and sagittal images only. Indeed, the os acromiale, an un-united acromial ossification center in adults, is one of the most frequently missed abnormalities by physicians who interpret MR. The reason is twofold. For one, the os acromiale, when viewed in the coronal or sagittal planes, bears a strong resemblance to a normal acromioclavicular (AC) joint (Figures 3 and 4). Second, the os acromiale is fairly common, being seen in approximately 8% of shoulder examinations. This combination of a not-uncommon yet challenging finding leads to the high frequency of missed diagnoses of the os acromiale. It is essential in routine MR imaging of the shoulder to obtain axials that extend superior to a point above the level of the acromion. The key to the simple and reliable diagnosis of the os acromiale lies in these upper axial images. On such images, the acromion is completely visualized, and the diagnosis of an os acromiale becomes much simpler. Only in the axial plane is one able to reliably visualize both the AC joint and the os acromiale on a single slice (Figure 5). Sports Health Orthopaedic Magnetic Resonance Challenge