Early diagnosis of an isthmic spondylolysis by MRI

Introduction: Early diagnosis of isthmic lumbar spondylolysis cannot always be established on plain radiographs and CT scans, only. In the case presen ted here, magnetic resonance imaging(MRI) showed typical bone marrow change s in T-1- and T-2-weighted images, even at an early stage. Case: A 11-year old female judoka complained of deep lumbar pain with local tenderness to p ressure at L3 to S1. Clinically, there was no neurologic deficit. Conventio nal x-ray showed no abnormalities. In contrast, MRI revealed a locally ill- defined bone marrow oedema in both pars interarticularis of the 5th lumbar verterbra. This was interpreted as the typical MR-tomographic feature of oc cult: stress fracture, which has to be seen as early evidence of isthmic sp ondylolysis. Complete restitution was achieved after conservative treatment . Conclusion: In early spondylolysis - presented here in form of a case rep ort-changes of MR signal intensity in the pars interarticularis may be dete cted, even before fracture lines are to be seen on plain radiographs. Furth er studies are necessary to confirm MRI to be the method of choice for earl y diagnosis.