Radiological Evaluation of Spinal Dysraphism using CT and MRI

Kanaka Rameswara Kumaran, S (2007) Radiological Evaluation of Spinal Dysraphism using CT and MRI. Masters thesis, Madras Medical College, Chennai.


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Spinal Dysraphism Is The Most Common Neural Tube Defect In Developing Countries Like India. The Incidence Varies From 0.5 To 11 Per 1000 Live Births In Different Parts Of Our Country, Largely Affecting The Lower Socioeconomic Strata Of The Population. The Etiology Of Neural Tube Defects Is Multifactorial. The Interaction Of Diverse Factors Related To Genetics, Nutrition And Environment Play An Important Role In The Etiopathogenesis. Some Of The Environmental Factors That May Contribute To Open Neural Tube Defects Are Uncontrolled Maternal Diabetes, And Certain Prescription Medications. It Has Been Proved That Deficiency Of Essential Vitamins Especially Folic Acid During Pregnancy Results In Higher Incidence Of Neural Tube Defects Which Led To Prophylactic Supplementation Of Folic Acid In The Antenatal Period. Spinal Dysraphism Is A Broad Term Encompassing A Heterogeneous Group Of Congenital Spinal Anomalies, Which Results From Defective Closure Of The Neural Tube During Early Fetal Life. Spinal Dysraphism Can Be Classified As Spina Bifida Aperta And Spina Bifida Occulta. Spina Bifida Aperta Is Most Common Type Of Spinal Dysraphism Representing A Serious Congenital Anomaly With Severe Neurologic, Musculoskeletal, Genitourinary, And Bowel Anomalies. It Encompasses Three Forms Namely Myelomeningocele, Myelocele And Rarely Meningocele. Females Show A Higher Incidence Than Males And Most Of Them Present At Birth And Are Immediately Taken For Surgical Repair And Hence Are Rarely Imaged In Unoperated Cases. Spina Bifida Occulta Is Characterized By Minor Neurological Manifestations And Presents At A Later Age. Most Distinct Clinical Findings Are Cutaneous Stigmata Like Dermal Dimple, Hemangioma, Cutis Aplasia, Dermal Sinus, Or Hairy Patch, Rudimentary Tail (Caudal Appendage). Segmentation Anomalies Of Spine Are A Common Feature Of Spinal Dysraphism And Along With Muscle Imbalances Due To Motor Deficits Result In Spinal Curvature Anomalies Like Scoliosis, Kyphosis And Lordosis. Scoliosis Is The Most Common Type Of Spinal Curvature Anomaly. Associated Anomalies Include Chiari Malformations, Hydromyelia And Hydrocephalus. Imaging Plays A Pivotal Role In The Diagnosis And Management Of Spinal Dysraphism. The Various Imaging Modalities Available Are PLAIN RADIOGRAPH ULTRASONOGRAM CT MRI PLAIN RADIOGRAPH Plain Radiograph Is The Base Line Investigation For Diagnosing Various Vertebral Anomalies Like Spina Bifida, Segmentation Defects,Spinal Curvature Anomalies, Bony Septum Of Diastematomyelia , Spinal Canal Widening And Lumbosacral Soft Tissue Swelling. How Ever Further Characterization Of The Lesions Require CT And MRI Imaging. ULTRASONOGRAM Spinal USG Is A Useful Imaging Modality For Diagnosis Of Spinal Dysraphism In Infancy Before Maturation Of The Vertebral Column. Neurosonogram Of The Brain Plays An Important Role In The Diagnosis Of Associated Anomalies Of Spinal Dysraphism Like Hydrocephalus And Chiari Malformations. COMPUTED TOMOGRAPHY Computed Tomography With Multiplanar Reformation Is An Excellent Modality For Identification And Characterization Of Vertebral Segmentation Defects, Spinal Curvature Anomalies And Bony Septum In Diastematomyelia. Various Forms Of Spinal Dysraphism Are Diagnosed By CT Based On The Attenuation Characteristics Of Their Contents. Thus Meningocele Shows Fluid Atteunation, Myelomeningoceles Shows Fluid And Soft Tissue Attenuation And Spinal Lipomas Show Fat Attenuation.CT Is Superceded By MRI In The Detection Of Soft Tissue And Associated Anomalies Of Spinal Dysraphism Like Hydromyelia, Hydrocephalus And Chiari Malformations. MAGNETIC RESONANCE IMAGING MRI Is The Imaging Modality Of Choice For Characterizing The Soft Tissue Spinal Anomalies Of Spinal Dysraphism Especially Spinal Cord. Meningomyelocele, Myelocele And Meningocele Are Evaluated According To The Signal Characteristics Of Their Contents. Spinal Lipomas Are Best Characterized Using Fat Suppression Sequences. Both CT And MRI Evaluates Dorsal Dermal Sinus Effectively. However MRI Supercedes CT In Further Characterization Of The Tract. MRI Best Depicts Fibrous Septum In Diastematomyelia While Bony Septum Is Best Demonstrated By CT. Further Characterization Into Split Cord Malformation I And II, Location, Extent Of The Hemicords, Site Of Rejoining And Associated Anomalies Are Best Demonstrated By MRI. MRI Best Characterizes Tethering Of Cord, Spinal Curvature Anomalies, Chiari Malformations, Hydromelia And Hydrocephalus. Thus CT And MRI Are Complementary To Each Other In Diagnosis And Characterization Of Spinal Dysraphism. Imaging Also Plays An Important Role In The Postoperative Follow-Ups.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Radiological Evaluation ; Spinal Dysraphism ; CT ; MRI.
Subjects: MEDICAL > Radio Diagnosis
Depositing User: Subramani R
Date Deposited: 29 Jun 2017 12:03
Last Modified: 14 Dec 2018 06:02

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