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SpineInfection & Inflammation
Mohamed Zaitoun
Assistant Lecturer-Diagnostic Radiology Department , Zagazig University Hospitals
EgyptFINR (Fellowship of Interventional
Neuroradiology)[email protected]
Knowing as much as possible about your enemy precedes successful battle
and learning about the disease process precedes successful management
Infection & Inflammation 1-Spondylodiskitis2-Spinal T.B. (Pott’s Disease)3-Epidural Abscess 4-Arachnoiditis5-Guillain-Barre Syndrome6-Chronic Inflammatory Demyelinating Polyneuropathy7-Sarcoidosis8-Multiple Sclerosis9-Neuromyelitis Optica10-Acute Transverse Myelitis11-Vitamin B12 Deficiency12-Paget Disease
1-Spondylodiskitis :a) Incidenceb) Etiologyc) Locationd) Radiographic Features
a) Incidence :-Spine infections may progress from spondylitis → diskitis
→ epidural abscess → cord abscess-In the pediatric age group infection often starts in the
intervertebral disc itself (direct blood supply still present) whereas in adults infection is thought to begin at the vertebral body endplate extending into the intervertebral disc space and then into the adjacent vertebral body endplate
-Infective spondylitis usually involves extradural components of the spine such as posterior elements , disks (diskitis) , vertebral body (osteomyelitis) & paraspinous soft tissues
b) Etiology :1-Pyogenic : Staphylococcus aureus >
Enterococcus > E. coli , Salmonella2-T.B.3-Fungal4-Parasitic
c) Location :-Can occur anywhere in the vertebral
column but more commonly involves lumbar spine
d) Radiographic Features :1-Plain Radiography2-CT3-MRI4-Nuclear Medicine
1-Plain Radiography :-Insensitive to the early changes of
diskitis/osteomyelitis with normal appearances being maintained for up to 2-4 weeks
-Thereafter disc space narrowing and irregularity or ill-definition of the vertebral endplates can be seen
-In untreated cases , bony sclerosis may begin to appear in 10-12 weeks
Lateral x-ray of discitis , L1-L2 disc height loss , endplate sclerosis & Indistinct endplates
Spondylodiskitis L2-3
Old Spondylodiskitis
2-CT :-CT findings are similar to plain film but
more sensitive to earlier changes-Additionally surrounding soft tissue swelling
, collections and even epidural abscesses may be evident
3-MRI :*T1 :-Low signal in disc space (fluid)-Low signal in adjacent endplates (bone marrow edema)*T2 (Fat sat or STIR especially useful) :-High signal in disc space (fluid)-High signal in adjacent endplates (bone marrow edema)-Loss of low signal cortex at endplates-High signal in paravertebral soft tissues
*T1+C :-Peripheral enhancement around fluid collection(s)-Enhancement of vertebral endplates-Enhancement of perivertebral soft tissues-Enhancement around low density center indicates
abscess formation (hard to distinguish inflammatory phlegmon from abscess without contrast)
*Diffusion :-Hyperintense in acute stage-Hypointense in chronic stage
T1 T2
T1+C
T1+C shows L1-L2 spondylodiskitis with epidural abscess
Diffusion
A: T2 sagittal showing high signal intensity of the intervertebral disc and vertebral body at the L4-L5 level , the prevertebral and epidural abscesses become hyperintense
B: T1 sagittal showing low signal intensity of the intervertebral disc and vertebral bodyC: T1+C sagittal showing heterogenous enhancement was seen and epidural and prevertebral
abscesses are better delineatedD: T1+C axial showing the diffuse enhancement in the L4 body and paravertebral soft tissue ,
epidural abscess is also seen
4-Nuclear Medicine :-A bone scan may be used to demonstrate
increased uptake at the site of infection and are more sensitive than plain film and CT , however lack specificity
-The classic appearance on multiphase bone scans is increased blood flow and pool activity and associated increased uptake on the standard delayed static images
2-Spinal T.B. (Pott’s Disease) :1-Incidence2-Pathology3-Radiographic Features4-Differential Diagnosis
1-Incidence :-Also known as tuberculous spondylitis-Refers to vertebral body and intervertebral
disc involvement with tuberculosis-N.B. :Brucellosis can present as granulomatous
osteomyelitis of the spine that can be difficult to distinguish from TB
2-Pathology :-There is usually a slow collapse of one or usually
more vertebral bodies which spreads underneath the longitudinal ligaments , this results in an acute kyphotic or gibbus deformity
-This angulation , coupled with epidural granulation tissue and bony fragments can lead to cord compression , unlike pyogenic infections , the discs can be preserved
-In late-stage spinal TB , large paraspinal abscesses without severe pain or frank pus are common leading to the expression cold abscess
Gibbus deformity (short-segment structural thoracolumbar kyphosis resulting in sharp angulation)
(A) T1 , (B) T2 show severe destruction of T11/T12 resulting in a significant kyphosis
*N.B. Differential Diagnosis of Gibbus deformity :a) Congenital :1-Achondroplasia2-Cretinism (hypothyroidism)3-Apert syndrome4-Coffin-Lowry syndrome5-Mucopolysaccharidoses :Hurler syndromeHunter syndromeMaroteaux-Lamy syndrome
b) Acquired :1-Compression fracture/vertebra plana :OsteoporosisLangerhans cell histiocytosisVertebral metastases2-Osteomyelitis/discitis :Pyogenic spinal osteomyelitisTuberculosis (Pott’s disease)3-Scheuermann disease
3-Radiographic Features :a) Plain Radiographyb) CT & MRI
a) Plain Radiography :1-Bone destruction is prominent , more prolonged onset
than with pyogenic bone destruction2-Loss of disk height , 80% (affects intervertebral discs ,
but mets no)3-Gibbus deformity : anterior involvement with normal
posterior vertebral bodies (Kyphosis)4-Vertebra plana or pancake vertebra (vertebral body has
lost almost its entire height anteriorly and posteriorly)5-Involvement of several adjacent vertebral bodies with
disk destruction6-Large paraspinous abscess7-Extension into psoas muscles (psoas abscess)
Destructive processes involving T11 associated with kyphosis
Cervical Pott’s disease presenting as a retropharyngeal abscess
AP (A) and lateral (B) X-ray of the lumbar spine showing spondylitis of the second lumbar vertebral body (L2) and lateral X-ray of the thoracic spine (C) of another patient showing a severe kyphosis as a consequence of T5-T6 spondylitis
b) CT & MRI :-Cross-sectional imaging is required to better assess
the extent of involvement and particularly for the presence of an epidural component and cord compression , MRI is the modality of choice for this, with CT with contrast being a distant second
-Features include irregularity of both the endplate and anterior aspect of the vertebral bodies with bone marrow edema and enhancement seen on MRI
-The collections are typically well circumscribed with fluid centers and well defined enhancing margins
(A) T1 shows destruction of the intervertebral disc space and endplates of the adjacent vertebral bodies is marked , vertebral body alignment is normal , (B) T2 shows diskitis and destruction of the endplates of the adjacent vertebral bodies
(A,C) T2 , (B,D) T1+C show destruction of L3 vertebral body (A , white arrow) with gibbus formation and retropulsion of bony fragments with compromise of the central canal at that level (A, black arrow) , there is fluid signal within the disc space that communicates with bilateral psoas abscesses (B, C, D, white asterisks) and pathologic enhancement is noted following contrast administration (B, D)
(A) T2 , (B) T1 show destruction of T8/T9 with some preservation of the disc
T1+C show destruction of L2 and L3 vertebral bodies with intraosseous and epidural abscess resulting in spinal canal stenosis
T1+C shows heterogeneous enhancement (arrows) of T8-T9 vertebral bodies , intraosseous abscess (asterisk)
T1+C
Edema of the bone marrow of L2 and L3 with intra-discal (blue star) and epidural abscess (red arrows)
Epidural abscess with cord displacement and compression (red arrows) and paraspinal phlegmon within the left psoas muscle (yellow arrows)
With paravertebral abscess
With paravertebral abscess
T2 shows collapse of L1 vertebral body with irregularity of superior end plate of L2 along with bilateral psoas abscesses
T1+C shows bilateral psoas abscesses
T1+C with fat sat shows peripheral enhancement of psoas collections consistent with the "cold" abscesses of spinal TB
3-Differential Diagnosis : -From non-specific infections :a) Site :-Lumbar vertebrae are more affected in non-specific
infections-T.B. : Dorsal & cervical then lumbarb) Course :-Acute with non-specific and prolonged in T.B.c) Soft tissue mass , collapsed vertebrae :-More with T.B.d) Sclerosis :-More with non-specific infections
e) MRI :1-T1+C : Rim enhancement of abscess on MRI is
suggestive of tuberculous spondylitis , however , rim enhancement can be observed in both tuberculous and pyogenic spondylitis :
-TB Spondylitis :Thin and smooth enhancement of the abscess wall
and well-defined paraspinal abnormal signal-Pyogenic Infections :Thick and irregular enhancement of abscess wall
and ill-defined paraspinal abnormal signal
(A) T1+C in TB shows smooth enhancement of intraosseous abscess (asterisk) , (B) T1+C in pyogenic abscess shows irregular enhancement of abscess (asterisk) presents in L4-5 disk space extending to L5 vertebral body
2-Hyperintense signal on T2 is more common in tuberculous spondylitis
3-Subligamentous spread to three or more vertebral levels was frequent in tuberculous spondylitis
4-Involvement of the posterior element has been reported in tuberculous spondylitis and very uncommonly in pyogenic spondylitis
(A) T2 in TB shows T8 and T9 vertebral bodies are heterogeneously hyperintense (arrows) , (B) T2 in pyogenic infection shows L4 and L5 vertebral bodies are isointense (arrows) to adjacent normal vertebrae
T.B. spondylitis, T1 shows heterogeneously hypointense signal (arrows) in T8-T9 vertebral bodies with epidural mass and subligamentous spread (arrowheads) from T7 to T10
Normal spinal posterior elements
Normal spinal posterior elements
(A) T1 , (B) T1+C show the extension of the abnormal signal intensity and enhancement of the vertebral body to both pedicle , anterior paraspinal and epidural soft tissues abnormal signal intensity and enhancement
(A) T1 , (B) T1+C shows the extension of the abnormal signal intensity and enhancement of the vertebral body to the right pedicle , right transverse process and adjacent right rib with marginal enhancing right paraspinal abscess
3-Epidural Abscess :a) Etiologyb) Radiographic Features
a) Etiology :-Rare but important emergency-Peak incidence in the fifth to seventh
decades of life with a male predominance -Usually secondary to disc or vertebral
sepsis
b) Radiographic Features :-Gadolinium-enhanced MRI is the imaging choice
for diagnosis of SEA, there are two basic patterns :
1-Phlegmonous stage of infection results in homogeneous enhancement of the abnormal area which correlate to granulomatous-thickened tissue with embedded micro-abscess without a significant pus collection
2-Liquid abscess surrounded by inflammatory tissue which shows varying degree of peripheral enhancement with gadolinium (long segment extradural mass with marginal enhancement)
T1+C shows epidural phlegmon
T2 (A) , T1 fat-saturated image after intravenous gadolinium (B) showing spondylodiscitis (arrow) complicated by an SEA at the C6-7 level (arrowheads)
T1+C fat-saturated revealing a posterior SEA from the vertebral level C5 to T5 (arrowheads)
T1+C
T1+C Fat saturation
4-Arachnoiditis :a) Definitionb) Etiologyc) Radiographic Features
a) Definition :-inflammation of the meninges and
subarachnoid space
b) Etiology :1-Infectious :-Meningitis2-Inflammatory :-Surgery-Intrathecal hemorrhage-Intrathecal compounds : myelographic contrast media ,
anesthetics3-Neoplastic :-Hematogenous spread of systemic tumors-Direct seeding of the CSF from primary central nervous
system tumors (GMB , medulloblastoma , ependymoma & choroid plexus carcinoma)
c) Radiographic Features :-The nerve roots are irregularly thickened and
clumped together (asymmetric distribution of nerve roots) , often stuck to the dura resulting in an empty thecal sac sign (is when the thecal sac appears empty on MRI of the lumbar spine , best seen on T2 , if the empty thecal sac sign is present , a diagnosis of adhesive arachnoiditis can be made)
-Intradural scarring / loculation (limited enhancement)-Intradural cysts (may be bright on T1)-Irregular margins of thecal sac
Normal nerve roots , (A) T2 shows normal lumbar roots are individually visible and because they float freely in the spinal fluid they follow the rules of gravity by positioning more towards the back , (B) T1 , hardly shows the nerve roots situated posteriorly in the spinal canal
Normal appearance of nerve roots in thecal sac on a T2 axial , note the slender caliber of the well-spaced nerve roots
Patient with mild arachnoiditis , suggested by thickened nerve roots (arrows) on T2 axial , which do not appear as spatially separated in the sac as is typical
T2 shows normal nerve roots T2 shows clumping of roots on the right side
Normal "fanning" of nerve roots within the thecal sac (arrows) is apparent on this T2 sagittal view of the lumbar region
In a patient with mild arachnoiditis, a T2 fails to demonstrate the usually fanning of nerve roots (arrow) on off-center sagittal views
T2 axial image reveals moderately thickened nerve roots with abnormal distribution in the thecal sac (arrows) , compatible with clumping
Post-operative , T2 axial image reveals moderately thickened nerve roots with abnormal distribution in the thecal sac (arrows) , compatible with clumping
The empty sac sign is present due to peripheral adherence of nerve roots (arrows) to the arachnoid
T2 shows the (empty sac) with clumping of the nerve roots to both sides
T2 sagittal reveals central clumping of nerve roots and pseudotethering (arrows)
T1+C shows no significant enhancement in association with the thickened nerve roots (arrows)
T2 sagittal image reveals thickened nerve roots (arrows) , intradural cysts (arrowheads) and pseudotethering
5-Guillain-Barre Syndrome :a) Incidenceb) Radiographic Featuresc) Differential Diagnosis
a) Incidence :-Defined as heterogeneous group of autoimmune
polyradiculopathy involving sensory , motor and autonomic nerves and is the most common cause of rapidly progressive flaccid paralysis
-Most cases preceded by upper respiratory tract infections or diarrhea 1-3 weeks before its onset
-Classical presentation of GBS includes symmetrical ascending muscle paresis or palsy , areflexia or hyporeflexia along with variable degree of sensory or autonomic involvement
b) Radiographic Features :-Diagnosed by combination of clinical presentation ,
CSF study and electrophysiological criteria-Radiologic studies are ordered to exclude other
causes and in cases where nerve conduction studies and CSF examination are equivocal
-MRI of the spine is most useful helps excluding other etiologies such as transverse myelitis and compressive causes of polyradiculopathy
-It is essential that contrast be administered if the diagnosis is suspected as non-contrast sequences are essentially normal
-Typical findings are :1-Nerve root thickening2-Enhancement surrounding the conus and
extending along the cauda equina , resulting from break down in the blood brain barrier which usually prevents enhancement
3-The most common site of enhancement is considered to be anterior nerve roots , although enhancement of the posterior nerve roots is also seen
-In the brain, the facial nerve is the most commonly affected
(A) T1 shows no abnormality , (B,C) T1+C show marked enhancement of the cauda equina (white arrows) & dorsal and ventral nerve roots (black arrows)
T1+C shows abnormal enhancement along nerve roots of cauda equina
T1+C show that the area of enhancement grew smaller during the clinical course
c) Differential Diagnosis :-The differential is essentially that of nerve root / cauda equina
enhancement :1-AIDS-related polyradiculopathy2-Arachnoiditis from any cause (e.g. post operative or post
intrathecal injection)3-Neurosarcoidosis4-Leptomeningeal carcinomatosis and lymphoma5-Chronic Inflammatory Demyelinating Polyneuropathy (CIPD) :-Acute presentation of CIPD can be similar to GBS-Difficult to differentiate in the first 6 weeks-After 6-8 weeks GBS should be improving whereas CIDP will
demonstrate chronic inflammation
6-Chronic Inflammatory Demyelinating Polyneuropathy (CIPD) :
a) Incidenceb) Radiographic Features
a) Incidence :-An acquired demyelinating disease involving
peripheral nerves and is generally considered the chronic counterpart to Guillain-Barre syndrome (GBS)
-Uncommon demyelinating disease-Patients typically present with a gradual and
protracted (> 2month) weakness of both proximal and distal musculature associated with areflexia and sensory change
b) Radiographic Features :-Thickening and enhancement of peripheral
nerves , brachial and lumbosacral plexus and nerve roots
-In many cases the nerves become so thickened that they resemble onion bulbs (The nerve roots appear bulbous tapering as they extend along the nerve)
T2 shows extensive hyperintense nodular masses along the cervical ventral rami (white arrows) and brachial plexus bilaterally (black arrows)
(A) T1 , (B) T2 , (C) T1+C show thickening of nerve roots of cauda equina
T2 of the right C7 and C8 nerve roots (arrowheads) and brachial plexus (arrow) demonstrated marked swelling and hyperintensity
(A,B,C) T1+C show massive hypertrophy of cervical nerve roots causing cervical spinal cord compression (A,B) dotted arrow : spinal cord , white arrows : nerve roots) and major hypertrophy of brachial plexi (C, white arrows)
(A) T1 , (B) T2 show root hypertrophy
T2 shows enlargement of spinal roots in the lower spinal canal , the lumbar and sacral ventral rami are massively enlarged (arrows)
T1+C shows enlarged enhancing roots of the brachial plexus passing between the scalene muscles (arrows)
7-Sarcoidosis :a) Incidenceb) Radiographic Features
a) Incidence :-Noncaseating granulomatous disease of
unknown etiology treated with corticosteroids
b) Radiographic Features :-Fusiform cord enlargement with abnormal
high signal intensity on T2-Patchy enhancement
(A) T2 , (B) T1 , (C) T1+C show high T2 signal within the spinal cord (arrowheads) , a portion of the lesion show intense enhancement (arrowhead) , the cord is mildly expanded
Sagittal T2 of the thoracic cord of a 45-year-old woman with sarcoidosis who presented with a subacute myelopathy
8-Multiple Sclerosis :a) Incidenceb) Radiographic Features
a) Incidence :-Presentation is usually between adolescence and
the sixth decade with a peak at approximately 35 years of age
-More in females-The spinal cord is known to be frequently involved
in MS or in combination with lesions in the brain-As many as 25% of cases have been found to
involve only the spinal cord-Most spinal cord lesions occur in the cervical cord
b) Radiographic Features :-T2 hyperintense-Typical spinal cord lesions in MS are relatively
small , peripherally located and multiple-They are most often found in the cervical cord and
are usually less than 2 vertebral segments in length
-A spinal cord lesion together with a lesion in the cerebellum or brainstem is very suggestive of MS
-Active lesions show enhancement-Active plaques may demonstrate restricted
diffusion
(A,B) T2 , (C) T1+C show multiple hyperintense lesions are visible in (A) & (B) which suggest multifocal disease , in (C) one of these lesions (arrow) is contrast enhancing
(A) T2 , (B) T1+C show a large lesion posteriorly within the cord, best seen on the T2 (on which it is hyperintense) with subtle abnormal contrast enhancement
(A) T2 , (B) T1+C
9-Neuromyelitis Optica :a) Incidenceb) Radiographic Features
a) Incidence :-Known as Devic disease-Typically found in patients that are somewhat
older than those with MS and there is an even stronger female predilection
-Characterized by :Optic neuritis (unilateral or bilateral) & myelitis with
lesions in both the optic nerve & the spinal cord with blindness and paraplegia
-Although NMO was initially thought of as a monophasic illness it is now evident that , like many patients with multiple sclerosis , it is usually a relapsing disease with symptomatic events separated by many years
b) Radiographic Features :-High T2 signal extend over long distances (over
three or more vertebral segments , often much more) , this is known as a longitudinally extensive spinal cord lesion (LESCL)
-Also helpful in distinguishing it from multiple sclerosis demyelination is the involvement of the central part of the cord (MS lesions tend to involve individual peripheral white matter tracts)
- May displace abnormal contrast enhancement
NMO , T2
NMO , (A) T1+C shows extensive multiple levels of cervical spinal cord involvement with edema and blood-brain barrier breakdown , (B) T2 indicates the extent of signal abnormality
10-Acute Transverse Myelitis :a) Incidenceb) Radiographic Featuresc) Differential Diagnosis
a) Incidence :-Affects individuals of all ages with peaks between
ages 10-19 years and 30-39 years -Acute transverse myelitis may occur as :1-An isolated idiopathic entity (with possible viral
or autoimmune etiology)2-Or in association with systemic diseases (lupus
or sarcoidosis)-The clinical presentation :Acute or subacute motor , sensory & autonomic
dysfunction related to a focal cord lesion
Sagittal T2 in a 43-year-old man who developed herpes zoster in the upper limbs and simultaneously a longitudinally extensive cervical myelitis
Sagittal T2 of the thoracic cord of a 45-year-old woman with sarcoidosis who presented with a subacute myelopathy
Sjogren syndrome , T2
b) Radiographic Features :-Up to 40% of cases have no findings on MRI-Centrally located abnormal cord high signal
intensity on T2 (involving the majority of the cord in cross-section)
-Extending over multiple segments (3-4 spinal segments)
-Fusiform enlargement of the cord-More commonly found within the thoracic cord -Variable enhancement patterns (none , diffuse ,
patchy & peripheral)
(A) Sagittal & axial T2 , (B) Sagittal & axial T1+C show the T2 signal abnormality extends to 3 or more cord segments and the lesion is centrally located (A) , also note the patchy enhancement (B)
(A) T2 sagittal , (B) T2 axial show an ill-defined area of hyperintensity within the thoracic spinal cord at the T-10 vertebral level , there is mild cord swelling at this level , the corresponding axial T2 shows an area of increased signal within the thoracic spinal cord
Axial T2 of cervical spine shows normal cord signal (A , circle) and increased T2 signal in the central cord (B , circle)
c) Differential Diagnosis :1-Multiple Sclerosis2-ADEM3-Neuromyelitis Optica4-Spinal Cord Infarction5-Spinal AVFs6-Intramedullary Spinal Tumors7-Radiation Associated Myelopathy
1-Multiple Sclerosis :-With multiplicity of cord lesions combined
with characteristic brain lesions consistent with M.S.
-Plaques are generally shorter than two vertebral body segments in length and involve less than half the cross-sectional area of the cord
-Plaques are characteristically peripherally located in the dorsal and lateral columns
M.S. , (A) Sagittal T2 shows discrete lesions without cord swelling , (B) Axial T2 shows that the lesion is peripherally located within the cord
M.S. , T2
2-ADEM :-Monophasic disorder that affects the brain
and occasionally the spinal cord-Typically following a recent (1-2 weeks
prior) viral infection or vaccination -Similar appearance to spinal MS plaques ,
more often associated with thalamic lesions
ADEM , T2
3-Neuromyelitis Optica :-Lesions are centrally located-The lesions in the cord are typically long (>
3 vertebral segments)-A history of severe optic neuritis should
raise suspicion of NMO
NMO , T2 show longitudinally extensive T2 signal abnormality in >3 vertebral segments (A) , the lesion is centrally located within the cord (B) with cord swelling (A)
4-Spinal Cord Infarction :-Arterial occlusions are rare and develop
acutely over minutes-Acute vascular occlusion can lead to spinal
cord infarction mimicking myelitis
Spinal cord infarction , sagittal T2 , arrow points to the linear lesion in the anterior cord-presumed anterior spinal artery occlusion
5-Spinal AVFs :-Arteriovenous fistulas (AVFs) usually
progress slowly due to gradual ischemia resulting from venous congestion
-Sudden decompensation of myelopathy caused by AVFs or bleeding into vascular malformations may also mimic myelitis
AVF , (A) T1 shows no definite abnormality , (B) T2 shows hyperintense longitudinally extensive lesion , (C) T1+C reveals dilated blood vessels on the surface of the cord
6-Intramedullary Spinal Tumors :-Present over weeks-This is not a difficult diagnosis when there is
an enhancing heterogenous lesion on MRI-Hemorrhage or infarction of tumors resulting
in acute swelling can mimic myelitis-Commonly associated with cysts and
syringohydromyelia
(A) T2 shows intramedullary tumor formation at C6-7 accompanying moderate syrinx , (B) T1+C shows the enhanced tumor within the spinal cord
7-Radiation Associated Myelopathy :-Usually slowly progressive but may occur
up to 15 years after the end of radiation treatment which may obscure the role of radiation therapy in causing the myelopathy
-Early in the course , cord swelling or enhancement may be seen but later atrophy may be the only finding
Sagittal T2 in a 34-year-old man with Hodgkin’s lymphoma who received radiotherapy and presented 2 years later with subacute myelopathy and thoracic sensory level. Long arrow points to the longitudinally extensive T2 hyperintense intramedullary lesion , the short arrow points to the vertebral changes in the field of radiation , the vertebra immediately below seems normal
11-Vitamin B12 Deficiency :a) Incidenceb) Etiologyc) Radiographic Featuresd) Differential Diagnosis
a) Incidence :-known as Subacute Combined
Degeneration-Most common in patients older than 40 and
especially older than 60 -The vitamin deficiency leads to
accumulation of methylmalonic acid which is myelinotoxic
b) Etiology :1-Malabsorption (most common) , e.g.
Crohn’s disease & other causes of terminal ileitis
2-Inadequate vitamin B12 intake (rare)3-Nitrous oxide toxicity (inactivates B12)-Treatment by intramuscular injection of B12
, the potential for reversal of clinical symptoms is inversely proportional to their duration & severity
c) Radiographic Features :-Most commonly there is symmetric bilateral
high signal within the dorsal columns , occasionally lateral columns extending over several vertebral body segments
-This appearance has been described as the (inverted V sign)
-Predominately in the lower cervical and upper thoracic region
-May enhance
-Often there is cerebral white matter change also
Inverted V sign
T2 shows hyperintensity (arrows) in the dorsal aspect of the cord spinal extending from the level of C2 to the level of C5
Axial T2 obtained through the cervical spinal cord at three separate levels from C3 to C4 show bilateral symmetric signal intensity abnormality within the dorsal columns (arrows)
T2
T1+C
d) Differential Diagnosis :1-Demyelination :-M.S. : also affects dorsal columns but usually over a
shorter length-T.M. : although longer length , usually not restricted to
dorsal columns2-Infectious causes :-HIV vacuolar myelopathy : may appear very similar-Herpes viruses myelitis-Syphilis (tabes dorsalis)3-Inflammatory :-Sarcoidosis4-Ischemia5-Neoplasm :-Astrocytoma : not particularly of dorsal columns , usually
more cord expansion , often enhance-Ependymoma : not particularly of dorsal columns , usually
more cord expansion , often enhance
12-Paget Disease :-Picture frame vertebral body : enlarged
square vertebral body with peripheral thick trabeculae and inner lucency (increased opacity of the cortex on all sides of the vertebral body whereas the characteristic sclerosis of the rugger jersey spine is seen only at the superior and inferior endplates)
-Ivory vertebra
Picture-frame and the increase in size compared to the vertebras above and below (arrow)
(A) Lateral radiograph shows uniformly increased opacity of entire T7 vertebra (arrow) , (B) CT shows increased opacity involving nearly the entire vertebral body
(A) T2 , (B) T1 shows mild increase in the AP diameter of L3 vertebral body with thick coarses trabeculations , irregular T1hypointensity noted in the posterior body and posterior elements of L3
Irregular thickening of the cortex in the body with preservation of marrow and spinal canal , few thick coarse trabeculae are seen with osteolysis of the rest , diffuse sclerosis with few lytic areas seen in the posterior elements
Mild expansion of the L3 vertebral body in the transverse and AP directions with few thickened trabeculae and lysis of the rest , mild expansion with sclerosis of the spinous process
