Comparing CT-like bone images based on FRACTURE MR with CT in pediatric congenital vertebral anomalies

BACKGROUND AND PURPOSE: Congenital vertebral anomalies are commonly associated with underlying spinal cord anomaly which necessitates imaging both the spinal cord and the bony vertebral column to understand the extent of the deformity better. While MRI is the gold standard for spinal cord imaging, it does not provide CT-like bone details. Many MR bone imaging techniques have been tested in various adult spine conditions in the past decade but not much has been described on their reliability in pediatric spine. We elaborate on our experience with Fast field echo resembling a CT using restricted echo spacing (FRACTURE) MR bone imaging in congenital vertebral anomalies in children.

MATERIALS AND METHODS: 11 pediatric patients referred to the imaging department for CT and MR study of congenital vertebral anomaly were prospectively included. After receiving informed consent from these patient's guardians, both studies were performed in a single setting and under a single sedation. FRACTURE MR was accelerated using the compressed SENSE technique to reduce the imaging time. We then compared FRACTURE MR and CT images for image quality and studied parameters like formation or segmentation anomalies, anomalous shape of vertebrae, and alignment deformities.

RESULTS: FRACTURE MR showed acceptable image quality with diagnostically limiting artifacts in only 1 patient. The inter-reader agreement was perfect in the assessment of vertebral body segmentation or formation anomaly and alignment abnormalities, and it was substantial for posterior element anomalies. The bone signal was lower in children under the age of 3 years of age due to a more immature and cartilaginous skeleton.

CONCLUSIONS: FRACTURE MR provides images of acceptable quality in pediatric spinal anomalies. The addition of this novel sequence can be complementary to conventional MR in providing osseous details and CT can be reserved for certain specific indications like post operative cases. This can help in reducing the radiation dose to this group of pediatric patients who will be serially followed up with imaging during their management.

ABBREVIATIONS: FRACTURE – Fats field echo resembling a CT using restricted echo spacing, CS – Compressed SENSE, KF – Klippel Feil, GRE – Gradient echo, UTE – Ultrashort Time to echo, ZTE – Zero Time to echo, CNR – Contrast-to-noise ratio, SNR – Signal-tonoise ratio, MSK -Musculoskeletal