Questioning the sensitivity of magnetic resonance imaging in early septic spondylodiscitis.

Septic spondylodiscitis is an uncommon disease, but one with serious complications and potentially high morbidity and mortality. The diagnosis is sometimes delayed, particularly in those patients with an insidious mode of onset and nonspecific symptoms. Several imaging methods are available to facilitate the early diagnosis of septic spondylodiscitis, and of these methods magnetic resonance imaging (MRI) has been reported to be the most sensitive, revealing abnormalities earlier than plain x-ray, gallium scan and bone scan. We report a case of septic spondylodiscitis in which MRI did not demonstrate evidence of discitis after a symptom period of seven days. The diagnosis was later confirmed by bone scan and repeat MRI. We suggest that a negative or equivocal MRI cannot exclude infective spondylodiscitis, especially in the early stages of the disease process. In such cases, it is important to note that the addition of a short tau-inversion recovery sequence will increase the sensitivity of MRI, and, additionally, gadolinium should be administered if the magnetic resonance study is negative and a strong clinical suspicion of spondylodiscitis exists.