3 AbstractPurpose:Spinal dysraphisms consist of a very wide range of pathologies and imaging appearances, some of which can be particularly challenging for radiologists and clinicians who primarily deal with adult patients. To simplify these potentially confusing congenital anomalies, spinal dysraphisms can be generally divided into two major categories - open and closed types.This electronic educational presentation will provide an overview of the imaging appearance of both open and closed type spinal dysraphisms. Imaging examples of each type will be provided to reinforce the spectrum of congenital abnormality that can be diagnosed, particularly on MRI. Also, image examples of spinal dysraphisms on fetal MRI will also be provided, which has become an increasing indispensable imaging modality to make early diagnosis of congenital anomalies in utero.Approach/Methods:Imaging studies from patients with congenital abnormalities of the spine and spinal cord are identified from a large tertiary referral center by retrospective case review. Of these, a wide range of cases is selected that represent the appearance of a majority of spinal dysraphisms, including multiple examples of fetal MRIs. From these cases, a PowerPoint presentation is generated focusing on the imaging appearance of each type of congenital abnormality and providing an organized approach to various open, closed and segmentation anomalies.Findings/Discussion:After viewing this presentation, the viewer will have greater familiarity with the appearance of spinal dysraphisms and be better equipped to diagnose these congenital abnormalities based on the organized approach provided.Summary/Conclusion:Congenital spinal cord and spinal abnormalities can be a complex topic for many radiologists. By reviewing this exhibit, the viewer will become more familiar with the appearance of spine dysraphisms, leading to a more organized approach to this spectrum of abnormalities.
4 Overview of Classification Open spinal dysraphismsClosed spinal dysraphismsWith subcutaneous massWithout subcutaneous massSimple dysraphic statesComplex dysraphic states (including segmentation anomalies)
5 Open Spinal Dysraphisms Types:MyelomenigoceleMyeloceleDefect in overlying skin causing exposure of neural tissueNeural placode protrudes through a midline skin defectCaused by incomplete closure of the neural tube
6 Open Spinal Dysraphisms MyelomeningoceleNeural placode protrudes above the skin surfaceNeural tissue, CSF and meninges are displacedFailure of neural tube closureT1 shows wide spinal dysraphism98% of open dysraphismsFrequently associated with other CNS abnormalitiesLumbosacral most commonMyeloceleAxial T2Sagittal T24-day-old boy with a low lying cord and herniation of the spinal cord, nerve roots and CSF sac dorsally through a spinal dysraphism
7 Cervicothoracic myelomeningocele Axial T2Sagittal STIRSagittal T2Spinal cord and cerebellar tonsils protruding through a wide posterior spinal dysraphism
8 Open Spinal Dysraphisms MyelomenigoceleMyeloceleNeural placode flush with skinCompared to protrusion above the skin as seen in myelomeningocelesCaused by defective closure of the primary neural tubeVery rareLess than 2% of open spinal dysraphisms
9 Closed Spinal Dysraphisms Neural tissue covered by skinWith subcutaneous mass:Lipomas with dural defectMeningoceleMyelocystoceleWithout subcutaneous mass:Simple dysraphic statesComplex dysraphic statesDisorders of midline notochord integration: dorsal fistula and neurenteric cystDiastatematomyeliaDisorders of notochord formation: caudal agenesisSegmental spinal dysgenesis
10 Closed Spinal Dysraphisms Neural tissue covered by skinWith subcutaneous mass:Lipomas with dural defectMeningoceleMyelocystoceleWithout subcutaneous mass:Simple dysraphic statesComplex dysraphic statesDisorders of midline notochord integration: dorsal fistula and neurenteric cystDiastatematomyeliaDisorders of notochord formation: caudal agenesisSegmental spinal dysgenesis
11 Closed Spinal Dysraphisms with subcutaneous mass Lipoma with dural defectDisorder of primary neurulation where mesenchymal tissue enters the neural tube and forms fatty tissue (lipoma)Clinically seen as a subcutaneous fatty mass above the intergluteal creaseTypes:LipomyeloceleLipomyelomeningoceleMeningoceleMyelocystocele
12 Closed Spinal Dysraphisms with subcutaneous mass Lipoma with dural defectLipomyeloceleLow lying spinal cord adheres to a large lipoma that extends through a posterior spinal dysraphismPlacode-lipoma complex is contiguous with subcutaneous fatLipomyelomeningoceleMeningoceleMyelocystoceleIntraspinal lipoma associated with the distal spinal cord (noted to be low lying, extending to the L4 level) and continuous with the subcutaneous fat through a posterior sacral bony defect at the S3 level.
13 LipomyeloceleAxial T1 images showing an intraspinal lipoma associated with the distal spinal cord that is continuous with the subcutaneous fat through a posterior sacral bony defect at the S3 level.
14 Closed Spinal Dysraphisms with subcutaneous mass Lipomas with dural defectLipomyeloceleLipomyelomeningoceleLipomyelocele + myelomeningoceleLipoma associated with the spinal cord and contiguous with subcutaneous fatProtrusion of thecal sac, nerve roots and spinal cord through dysraphic posterior elementsSpinal cord is always tetheredMeningoceleMyelocystoceleSagittal T1
15 Lipomyelomeningocele Sagittal T1Axial T1Axial T172-day-old boy with low-lying conus (tethered cord), spinal cord mass with predominately fat signal (lipoma) contiguous with the subcutaneous fat. The mass also has associated CSF and soft tissue signal.
16 Closed Spinal Dysraphisms with subcutaneous mass Lipomas with dural defectMeningoceleHerniation of CSF-filled sac lined by dura and arachnoid through an osseous defect of the posterior spinal elements (spina bifida)Does NOT contain spinal cordCompared to myelomeningoceleLumbar and sacral most commonMyelocystoceleSagittal SSFSEAxial SSFSEFetal MRI showing L5-S1 spinal dysraphism with likely associated meningocele
17 Fetal MRI: Thoracic Meningocele Sagittal TruFispAxial HasteProtrusion of a CSF filled sac through a thoracic dysraphism on fetal MRI completed at weeks.
18 Same patient at 1 day old: Thoracic Meningocele Sagittal T2Axial T2Protrusion of a CSF filled sac through a thoracic dysraphism, similar in appearance compared to the fetal MRI.
19 Closed Spinal Dysraphisms with subcutaneous mass Lipomas with dural defectMeningoceleMyelocystoceleDilated central spinal canal (inner cyst) protruding through posterior dysraphic spine into dilated subarachnoid space (outer cyst) in subcutaneous locationCaused by incomplete fusion of dorsal neural foldsTerminal myelocystocele: herniation of terminal syrinx into posterior meningoceleSagittal T28-month-old girl with a tethered spinal cord and myelocystocele.
20 Closed Spinal Dysraphisms Without subcutaneous mass:Simple dysraphic statesComplex dysraphic states
21 Closed Spinal Dysraphisms without subcutaneous mass Simple dysraphic statesIntradural lipomafilar lipomatight filum terminalepersistent terminal ventricledermal sinus
22 Closed Spinal Dysraphisms without subcutaneous mass Simple dysraphic statesIntradural lipomaLipoma within the dural sac at the dorsal midlineLumbosacral most commonTypically present with tethered-cord syndrome: progressive neurologic abnormalities in the setting of traction on low-lying conusfilar lipomatight filum terminalepersistent terminal ventricledermal sinus
23 Intradural LipomaSagittal T1Sagittal T23-month-old boy with a fat signal lesion in the posterior spinal canal compatible with intradural lipoma. The conus is tethered to the lipoma and low-lying.
24 Closed Spinal Dysraphisms without subcutaneous mass Simple dysraphic statesIntradural lipomafilar lipomaFibrolipomatous thickening of the filum terminaleHyperintense strip of signal on T1 with thickening of filumNormal variant if no tethered-cord syndrometight filum terminalepersistent terminal ventricledermal sinusCoronal T1
25 Filar LipomaSagittal T1Sagittal T1 FS +C32-month-old girl with hyperintense signal along the filum terminale on T1WI that shows signal drop out on post-contrast fat-saturated T1WI.
26 Closed Spinal Dysraphisms without subcutaneous mass Simple dysraphic statesIntradural lipomafilar lipomatight filum terminaleHypertrophy of the filum terminaleCan cause tethering and low lying conus (normal above L2-L3)persistent terminal ventricledermal sinusSagittal T25-year-old girl with thickened filum terminale conus at L2-L3.
27 Closed Spinal Dysraphisms without subcutaneous mass Simple dysraphic statesIntradural lipomafilar lipomatight filum terminalepersistent terminal ventricleSmall ependymal lined cavity in conus located immediately above filum terminaleNonenhancing dilation of the central spinal canal in the conusdermal sinusAxial T2
28 Closed Spinal Dysraphisms without subcutaneous mass Simple dysraphic statesIntradural lipomafilar lipomatight filum terminalepersistent terminal ventricledermal sinusEpithelial lined fistula connecting the neural tissue or meninges to the skinCan lead to infectionLumbosacral most commonOften associated with a spinal dermoidSagittal T2Dorsal dermal dermal sinus extending into the thecal sac at the S1-S2 level
29 T1T1 C+T2T210-year-old with a dorsal dermal sinus and associated intramedullary dermoid (characteristic well circumscribed appearance with partial diffusion restriction).DWIADCT1 C+
30 Dorsal Dermal SinusDorsal dermal sinus tract communicating with an intradural lipoma through a defect in the posterior spine in a 3-month-old boy with a sacral dimple
31 Closed Spinal Dysraphisms without subcutaneous mass Complex dysraphic statesDisorders of midline notochord integrationneurenteric cystdiastatematomyeliaDisorders of notochord formationcaudal agenesisSegmental spinal dysgenesis
32 Closed Spinal Dysraphisms without subcutaneous mass Complex dysraphic statesDisorders of midline notochord integrationneurenteric cystIntraspinal cyst lined by mucin-secreting enteric mucosaCaused by failure of separation of dorsal ectoderm (spinal cord) and ventral endoderm (foregut)Iso- to hyperintense to CSF on T1 depending on mucin contentdiastatematomyeliaDisorders of notochord formationcaudal agenesisSegmental spinal dysgenesisSagittal T1
33 Neurenteric Cyst: Craniovertebral Junction Sagittal T2Axial T2Intradural neurenteric cyst at the craniovertebral junction with a sinus tract extending ventrally
34 Closed Spinal Dysraphisms without subcutaneous mass Complex dysraphic statesDisorders of midline notochord integrationneurenteric cystDiastatematomyeliaSeparation of spinal cord into two hemicordsUsually symmetric with variable length of separationType 1- individual dural tubes separated by osseous or cartilaginous septumType 2- single dural tube with two hemicords, sometimes intervening fibrous septumDisorders of notochord formation / secondary neurulationcaudal agenesisSegmental spinal dysgenesisSoft Tissue WindowBone window17-month-old boy with splitting of the thoracic spinal cord by an intervening bony septum (type 1).
35 Diastatematomyelia: type 2 Axial T1Axial T2Axial T1T7T7L319-month-old boy with splitting of the spinal cord at the T7 level. The spinal cord rejoins into a single structure at the L3 level and is contained within a single dural sac.
36 Closed Spinal Dysraphisms without subcutaneous mass Complex dysraphic statesDisorders of midline notochord integrationneurenteric cystdiastatematomyeliaDisorders of notochord formation / secondary neurulationCaudal agenesisTotal or partial agenesis of the spinal columnCan be associated with anal imperforation, renal and genital anomalies, pulmonary hypoplasia and limb abnormalitiesSegmental spinal dysgenesisNewborn boy with multiple anomalies including absence of the spine from the mid-thoracic level caudally.
37 Caudal AgenesisSagittal T2Coronal CT21-year-old woman with abnormal termination of the spinal cord at T10-11 and associated complete absence of the sacrum.
38 Closed Spinal Dysraphisms without subcutaneous mass Complex dysraphic statesDisorders of midline notochord integrationneurenteric cystdiastatematomyeliaDisorders of notochord formationcaudal agenesisVertebral segmentation anomaliesVarious appearancesCT helpful17-year-old woman with a fusion anomaly at the lumbosacral junction
39 Vertebral Segmentation Anomalies 8-year-old girl with scoliosis and a partial sagittal partition segmentation anomaly at T7.
40 Vertebral Segmentation Anomalies 75-day-old boy with vertebral anomalies including multiple hemivertebrae.
42 Summary of Classification Open spinal dysraphisms: defect in skin exposing neural tissueClosed spinal dysraphisms: neural tissue covered by skinWith subcutaneous massWithout subcutaneous massSimple dysraphic statesComplex dysraphic states (including segmentation anomalies)
43 SourcesAdzick NS: Fetal myelomeningocele: natural history, pathophysiology, and in-utero intervention. Semin Fetal Neonatal Med. 2010; 15(1): 9-14.Aydin AL et al: Prenatal diagnosis of a large, cervical, intraspinal, neurenteric cyst and postnatal outcome. J Pediatr Surg. 2009; 44(9):Muthukumar N: Terminal and nonterminal myelocystoceles. J Neurosurg. 2007; 107(2 Suppl):87-97.Rufener, SL, Ibrahim M, Raybaud, CA, Parmar, HA. Congenital spine and spinal cord malformations- pictoral review. American Journal of Roentgenology. 2010; 194: S25-S37.Tortori-Donati P et al: Spinal dysraphism: a review of neuroradiological features with embryological correlations and proposal for a new classification. Neuroradiology. 2000; 42(7):