Andrea Hernandez

Diagnosis of Osteomyelitis in Children: Utility of Fat-Suppressed Contrast-Enhanced MRI

OBJECTIVE The purpose of this study was to determine whether the use of fat-suppressed contrast-enhanced MRI, compared with unenhanced MRI alone, increases reader confidence in the diagnosis of osteomyelitis and its complications in children. MATERIALS AND METHODS MRI studies of 78 skeletally immature children and adolescents (median age, 3.6 years) with suspected nonspinal osteomyelitis were reviewed in consensus by two readers. Unenhanced images were evaluated first and then contrast-enhanced MR images. Images were scored for the presence or absence of osteomyelitis, abscess, septic arthritis, and physeal involvement on a 5-point scale ranging from definitely absent to definitely present. Forty-two additional studies were evaluated to test interobserver agreement. RESULTS Osteomyelitis was clinically diagnosed in 40 cases (51%). There was no significant difference between the sensitivity and specificity of unenhanced MRI (p = 1.0) and those of contrast-enhanced MRI (p = 0.77) for the diagnosis of osteomyelitis. Nonetheless, there was a significant (p < 0.001) increase in confidence in the diagnosis of osteomyelitis and its complications. This increase in confidence was most pronounced for the diagnosis of abscess (46%). The addition of contrast enhancement was least useful in findings deemed definitely absent on unenhanced MR images. CONCLUSION Although it does not increase the sensitivity or specificity of the diagnosis, use of contrast-enhanced MRI does increase reader confidence in the diagnosis of osteomyelitis and its complications in cases in which bone or soft-tissue edema is found on unenhanced images. In the clear absence of edema on unenhanced images, however, contrast enhancement is not needed.

Diffusion-weighted and diffusion tensor imaging for pediatric musculoskeletal disorders

Diffusion-weighted imaging (DWI) is a powerful tool that has recently been applied to evaluate several pediatric musculoskeletal disorders. DWI probes abnormalities of tissue structure by detecting microscopic changes in water mobility that develop when disease alters the organization of normal tissue. DWI provides tissue characterization at a cellular level beyond what is available with other imaging techniques, and can sometimes identify pathology before gross anatomic alterations manifest. These features of early detection and tissue characterization make DWI particularly appealing for probing diseases that affect the musculoskeletal system. This article focuses on the current and future applications of DWI in the musculoskeletal system, with particular attention paid to pediatric disorders. Although most of the applications are experimental, we have emphasized the current state of knowledge and the main research questions that need to be investigated.

Fetal MRI of clubfoot associated with myelomeningocele

BackgroundThe sensitivity and specificity of evaluating clubfoot deformity by MR in high-risk fetuses is currently unknown.ObjectiveTo correlate fetal MRI with US in the assessment of clubfoot and to identify the MRI features most characteristic of clubfoot.Materials and methodsWith IRB approval and informed consent, the presence of fetal clubfoot was prospectively evaluated in mothers referred for MRI for a fetus with myelomeningocele. Two radiologists blind to the US results independently reviewed the MRI for the presence of clubfoot. MRI results were compared with US results obtained the same day and birth outcomes.ResultsOf 20 patients enrolled, there were 13 clubfeet. Interobserver agreement for the presence of clubfoot was 100%. The sensitivity of the MRI exam was 100% and the specificity 85.2%. A dedicated sagittal imaging plane through the ankle region allowed the most confident diagnosis; medial deviation of the foot relative to the leg was seen in all 13 fetuses with clubfoot.ConclusionThe correlation of fetal MRI with US in the evaluation of clubfoot yields a sensitivity of 100% and specificity of 85.2%. The sagittal plane provided the most useful information.