Purpose or Case Report: Caudal regression syndrome (CRS) refers to a rare disorder with varying degrees of agenesis or malformations of the lower thoracic, lumbar, and sacral spine as well as the spinal cord with varying clinico-radiological features. Estimated incidence ranges from 5-10:100,000 births. Imaging is an integral part of the diagnosis and management of this condition. An extensive review of the imaging spectrum of CRS with several case-based examples would enable a complete understanding of the condition.

We reviewed the imaging appearance of several cases of caudal regression, including in utero cases, from our tertiary care university based pediatric hospital. The various associated malformations, especially of the spinal cord, were examined in detail. We also analyzed the clinical symptomatology of these patients and correlated them with the imaging patterns. A detailed review of related literature was performed and consolidated information on the clinico-radiological spectrum of CRS was compiled.

The following aspects of CRS have been discussed in detail:
Predisposing maternal conditions and pathogenesis of CRS in the fetus.
Pang groups 1 and 2 CRS and their imaging features.
Renshaw types 1 to 4 sacral agenesis and their imaging features.
Role of radiographs, ultrasound, and MRI in CRS.
Spectrum of MRI features in the cord including shape of conus, level of termination, presence of cord tethering, associated neural tube defects and associated syrinx.
Clinical manifestations of various types and their correlation with imaging features.
Imaging features correlating with progressive versus static neurological deficits.
Imaging features that could signal potential benefit from surgical treatments.
Prenatal diagnosis of CRS on obstetric ultrasound and fetal MRI: Imaging patterns and importance of antenatal diagnosis.
Associated anomalies and syndromes and necessary additional imaging in CRS cases.
Pitfalls in imaging of CRS.

A complete understanding of CRS including clinico-radiological correlation of symptomatology and imaging appearance in CRS would enable detailed and accurate reporting of these scans. In particular, identifying imaging features that correlate with progressive neurological deficits and those that may benefit from surgical intervention can significantly improve patient management.
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