A Study of Normal Variants on CT and MR Imaging Central Nervous System

Kajal Mitra, Chetna Ratnaparkhi, Glossy Sabharwal


Aims, Objectives and Background: No two human bodies develop in exactly the same way. Variations among
them are common and are considered normal. Nevertheless in certain pathological conditions these normal
variants, which would otherwise be considered normal incidental findings, can assume clinical significance
because of their resemblance to genuine true to life irregularities and pathologies.
The aim of this study is to help clinicians and academicians, whenever possible, to rule out the possibility of a
normal variant on CT and MRI. The study addresses for the most part, the issue of how to distinguish what is
normal from the anomalous and how to describe these normal findings.
Materials and Method: The study was done at NKP Salve Institute of Medical Sciences and Lata Mangeshkar
Hospital in the region of Hingna and Nagpur where a retrospective and prospective study was performed to
describe the normal variations on CT and MRI. Out of the randomly selected 2000 routine scans that were
performed from June 2009 to June 2010, there were 50 patients who showcased normal variants in the scan.
Out of these, 30 showed anatomical variant in the Brain scans, 10 involving the Musculoskeletal system, 3
involving the PNS, 2 involving the Skull and 5 showed normal variations in the Abdomen cross sectional
imaging. These cases were compared to earlier such variations which became a premise to distinguish normal
variants from the anomalous. Furthermore these cases were compared with renowned previous studies done
at an earlier date. The cases were then classified according to their region and anatomy and results were
Results and Conclusion: The normal variant cases were classified according to their anatomy and percentage
of normal variants to the number of total scans performed was calculated according to the classification.
Detailed result and conclusions to be illustrated in subsequent discussions.
Key Words: Normal variants, CT, MRI, Dandy Walker, calcification.

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