MR case: Cervical Koch’s

case of cervical infective spondylodiskitis with concurrent intramedullary cord tuberculoma

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MR Imaging in Multiple Sclerosis: Overview and role of MR imaging: Article by Dr H.S.Das:

Multiple sclerosis (MS) is an idiopathic inflammatory and most common demyelinating disease of the CNS. Most people with this disease are affected in their prime of their lives, usually between 20 and 40 years of age though exceptions have been documented. Cause of this disease remains unknown. Genetic, viral, autoimmune and environmental factors have been implicated in the disease.

 Pathologic hallmark of MS is multicentric and multiphasic CNS inflammation and remyelination scattered over space and time. In MS, cells of the immune system invade the CNS and destroys the myelin cover leading to demyelination of the axon and damage to the axon itself. In response, other cells of the CNS produce a hard sclerotic lesion (“ the MS plaque”) around the multiple demyelinated sites. Areas of axonal damage can be measured by magnetic resonance spectroscopy (MRS) and is found to correlate with clinical disability. Few lesions in non eloquent areas do not produce clinical symptoms or nerological dysfunction. Such lesions are referred to as “silent lesions”. Approximately 1 per 1000,000 people acquire MS internationally. Throughout adulthood , the female to male ratio is 2:1.

Clinical features:

Sensory problems occur in 20%-50% of patients and are often the earliest symptoms. These manifest as tingling, tight band feeling, crawling sensations etc are found in the extremities and in the trunk and are referred to as paresthesias. Few patients may experience an electric like sensation that goes down the back and legs with head or neck motion (Lhermitte’s sign).

Optic neuritis is the presenting symptom in 15%-20% of patients with MS and usually starts with blurring of vision followed by loss of vision. May appear on one side followed by a later appearance in the other. It rarely involves both eyes simultaneously.

Spasticity occurs due to cortico-spinal tract involvement . Occurs with the initial attack of MS in 30%-40% of patients. It is present in 60% of patients with progressive disease. Usually legs are involved more than the arms.

Other clinical features of MS includes gait and balance incoordination, bladder & bowel dysfunction, fatigue (the single most complaint of people with MS), heat sensitivity, cognitive and emotional dysfunctions etc.

Diagnosis of MS is based on a classic presentation (optic neuritis, transverse myelitis, paresthesias etc) and on the identification of other neurological abnormalities, which is indicated by the patients history and clinical examination. Typical findings in MRI greatly help to establish diagnosis of MS. Patients with atypical presentations and /or a normal or atypical MRI may require evoked potential studies to know about subclinical neurological abnormality. CSF analysis is done to exclude treatable conditions and to document immunological activity in the CNS. Oligoclonal bands are present in over 90% of definite MS, though these can be seen in other inflammatory diseases and in 7% of normal controls. An IgG index of >0.7 is seen in 86%-94% of MS patients and is usually the first CSF abnormality in early MS. 25% patients show elevated protein levels. Presence of myelin basic protein in CSF indicates demyelination though these also can be seen in other neurological conditions like infections, infarct etc. However this protein can be found in the first 2 weeks after a substantial exacerbation in 50%-90% of patients.

Course of disease: The natural course of MS is highly variable and it is impossible to predict the nature, severity or timing of progression in a given patient. Patients with sensory problems tends to have a better prognosis than those with spasticity or paralysis. Another factor that influences prognosis is age of onset. Disease progression tends to be more rapid in patients who experience their first symptoms after age 40. Other factors predictive of rapid progression include male gender, frequent attacks and burden of disease as detected by MRI scans.

Classifications of MS :

Clinically definite MS is further categorized according to disease course. Relapsing-remitting MS (RR-MS) is characterized by symptoms that develop over a period of a few hours to a few days, followed by recovery and a stable course between relapses. Approximately 80% of patients are initially dignosed with relapsing-remitting MS. Almost 50% of patients with relapsing- remitting MS eventually develop secondary-progressive MS (SP-MS) characterized by gradual neurological deterioration with or without superimposed acute relapses. If there is continual disease progression from onset with only minor fluctuation the classification becomes primary-progressive MS (PP-MS). PP-MS occurs in approximately 10 % of patients and mostly who are > 40 years of age. Progressive-relapsing MS (PR-MS), a rare from of the disease, is characterized by gradual neurological deterioration from the onset of symptoms to subsequent relapses.

MR IMAGING IN MS :

MR imaging is the modality of choice in patients with MS . Use of MRI in MS was first described by Young et al in 1981. Previously spin echo ( SE ) sequences like T1, T2 and PD weighted images are commonly used to screen patients with MS. Recently fast or turbo spin echo ( FSE & TSE ) techniques with similar PD and T2 weighted lesion contrast has become popular because this sequences utilize ¼ to 1/3rd of acquisition time. Very small lesions can be missed on FSE sequences because of edge blurring, but taking thinner slices compensates it.

Recent MR developments in imaging of white matter disease :

Nowadays FLAIR ( fluid attenuated inversion recovery ) sequences are widely used because heavily T2 weighted images can be obtained with CSF suppression and enables greater lesion conspicuity in the gray white interface areas. Another technique is EPI ( echo planar imaging ). Use of EPI FLAIR is very useful in detecting early lesions that do not enhance such as Demyelinating disease, acute infarcts and infection.

Diffusion weighted imaging (DWI) :

Normal white matter exhibit anisotropic diffusion with increased diffusion parallel to white matter fibers and restricted diffusion present perpendicular to these fibers. Demylination results in increase in extracellular space which in turn results in increase in water diffusion and diffusion coefficient as compared to normal white matter. Hence in MS, both in acute and chronic plaques there will be increase in diffusion coefficient. Acute plaques has higher diffusion coefficient than chronic plaques probably due to gliosis in chronic plaques. Currently modalities like DTI ( diffusion tensor imaging ) and FA ( fractional anisotropy ) are being utilized for more research in MS.

Quantative magnetisation transfer ( MT ) technique :

Useful in MS patients on drug therapies to know the disease activity. In active plaques there is little demyelination and their MT ratio is slightly reduced which indicates that lesions are most likely to respond to methylprednisolone and more likely to disappear. In contrast chronic plaques have more demyelination and very low MT ratio. These are unlikely to respond to any drug therapy. This technique is now applied to other white matter disease also.

Magnetic resonance spectroscopy (MRS) :

This technique does not produce images but graphs that display levels of metabolites as zones of different colors or shades of gray known as spectroscopic images. In MS tissue metabolite like NAA ( N – acetyl aspartate ) is decreased in chronic plaques and remains normal in active plaques.

MR appearance of MS lesions:

Lesions are typically nodular or ovoid in appearance. Size varies from few mm to more than 1cm. Lesions have propensity to involve the large white matter tracts particularly corpus callosum, medial longitudinal fasciculus and middle cerebellar peduncle. Lesions can also be found in juxtacortical location involving the “U” fibres, along the perimedullary veins at the calloso-septal interface and also in periventricular location giving rise to the classical “Dawson’s fingers appearance”. MS lesions however can involve any portion of the white matter. Recently presence of “ Subcallosal Striations”has been described using sagittal FLAIR sequence. These are thin white lines radiating from the calloso-septal interface and represents the earliest manifestation of MS in this location. Occasionally, MS lesions present as large lesions with mass effect and vasogenic edema indistinguishable from brain tumor by MR imaging ( tumefactive MS plaque). Other nonspecific findings include thinning of the corpus callosum, dirty white matter on T2 weighted images and deposition of non haem iron in the basal ganglia with progression of the disease

Spinal MS :

Spinal MS has a predilection for the cervical spinal cord ( 67 % of cases), with preferential eccentric involvement of the dorsal and lateral areas of the spinal cord abutting the subarachnoid space around the cord. About 55 to 75 % of patients with MS have spinal lesions at some point of time during the course of the disease. As many as 20% of spinal MS lesions are isolated. Spinal lesions enhance after contrast administration. Enhancement may last for 2 to 8 weeks. Steroids do not suppress enhancement of active plaques. Chronic plaques do not enhance and often demonstrate focal cord atrophy. Lesions of other etiologies ( eg, viral myelitis, ADEM ) may resemble MS plaques and must be considered along with the clinical history and the patients sign and symptoms.


 

 


Legends for photos:

Fig1: T2 sagittal image showing Cord change in MS

Fig2. FLAIR coronal image showing plaques (bright lesions) in the supra & infratentorial compartments of brain. Notice the upper cervical cord lesion.

Fig3:. T2 weighted axial image showing multiple Demyelinating plaques (bright lesions) in bilateral periventricular areas.

Typical MR morphology of MS lesion:

Initially MS lesions are isointense to mildly hypointense (black) on T1 weighted images. With time, the hypointensity progresses to develop the so called “T1 black hole”. Some lesions show slight peripheral hyperintensity surrounding the lesion due to presence of free radicles in the surrounding inflammatory tissues. On T2 and PD weighted images the lesions are usually hyperintense (bright).

Role of contrast administration in MS :

In MS contrast enhanced MRI plays an important role depending on the clinical context. Contrast enhancement in general indicates the presence of active inflammatory process. Non enhancing lesions are thought to be chronic lesions. Presence of enhancing and non enhancing lesions is strong evidence to indicate that these multiple lesions are separated in time supporting diagnosis of MS. Presence of ring enhancement suggest reactivation of an old lesion, the central nonenhancing portion representing the “burnt out” portion of the lesion. An incomplete or open ring enhancement is more indicative of an MS lesion.

MR imaging criteria for clinical progression to MS in patients with clinically isolated syndromes ( CIS). MS typically presents as an acute reversible episode of neurologic dysfunction.

Paty et al ( 1988 ) : 4 lesions ( Paty A)

  • : 3 or more lesions, including 1 periventricular lesion ( Paty B)

  • Sensitivity 86 %, Specificity 54 %

Fazekas et al (1988) : 3 lesions with 2 of the following properties.

  • : 5 or > 5 mm diameter of lesion.

  • : Infratentorial or periventricular location.

  • : Sensitivity 86 %, Specificity 54 %

Barkhof et al ( 19 97 ) : 4 lesions criteria

  • : 1 or > 1 Juxtacortical lesion.

  • : 1 or > 1 enhancing lesion or > 9 nonenhancing lesion.

  • : 1 or > 1 infratentorial lesion.

  • : 3 or > 3 periventricular lesions. ( Sensitivity and specificity 73% )

Proposed new diagnostic category : MR imaging supported definite multiple sclerosis ( MRISDMS)

At least one MS –like clinical episode with appropriate clinical findings, remission not necessary.

Abnormal MR image findings ( strongly suggestive of MS).

  • Four or more white matter lesions ( > 3 mm diameter ).

  • 3 lesions with at least one located in periventricular location.

  • One or more of the following specific features.

  • Involvement of corpus callosum.

  • Infratentorial location.

  • Oval shape.

  • > 6 mm in diameter.

  • Some but not all enhancing.

Variants of MS –

Balo’s concentric sclerosis :- Rare, affects young adults, last for few months, concentric bands of intact myelin and demyelinated zones, responds to steroid.

Devic’s disease :- ( neuromyelitis optica) Spinal cord and optic nerves affected. Brain spared . Brain MRI normal. MRI spine shows striking lesions.

Marburg’s disease :- Acute form of MS. Fulminant and progressive.

Schilder’s disease :- Rare, affect children, visual problems and cortical blindness, Seizures, headache, vomiting, large bilateral hemispheres demyelination.

Monophasic syndromes :- Optic neuritis, acute transverse myelitis, ADEM

 

 

 

 

IMAGING IN CEREBRAL VASCULAR PATHOLOGIES:

 

IMAGING IN CEREBRAL VASCULAR PATHOLOGIES:

 

EVOLUTION OF INTRACRANIAL HEMATOMA

 

1. Immediate


– liquid with 95% O2 saturated Hb, T2 hyper, T1 iso within seconds platelets thrombi form & cells aggregate

 2. Hyper acute stage –

4-6 hrs, fluid serum begins to disperse

Protein clot retracts, red cells become spherical, oxy

Early peripheral edema begins, T2 iso, T1 iso

OxyHb is diamagnetic with no unpaired electrons,

CT – isodense for 1-3hrs, then becomes dense, 60-100HU
3. Acute stage

– 7-72 hrs, red cells begin to compact, deoxyhb

Central portion T2 hypo, T1 iso

DeoxyHb is paramagnetic with 4 unpaired electrons, T2 shortening

Sheilded from H2O by globin, prevents T1 shortening

No proton-electron relaxation enhancement can occur

Edema pronounced in periphery

Dense on CT, window width of 150-250 best

 

4. Subacute stage –

1-4 wks, methemoglobin starts day 4

Begins at periphery & progresses towards anoxic center

Cells begin to lyse at 1 week releasing metHb, decrease in edema

Perivascular inflammatory reaction begins with macrophage at periphery

Ring Enhancement caused by this process

T1 BRIGHT due to 5 unpaired electrons exposed by globin change

Proton-electron relaxation enhancement does occur

Periphery affected 1st, middle remains iso initially

T2 HYPO early when methemoglobin still in RBC

BRIGHT once the cell breaks down & Hb diluted in water

CT attenuation decreases approx 1.5HU per day

CT is NOT an accurate indicator of age, due to variable Hb etc

 

5. Early Chronic stage

– >4wks, edema & inflammatory reaction subside

Vascular proliferation encroaches on haematoma decreasing its size

Dilute uniform pool of extracellular metHb with vascular walls

Macrophage contain ferritin & hemosiderin at periphery

T2 hypo due to strong magnetic susceptibility

T1 iso due to fact that hemosiderin is water insoluble

Hypodense on CT unless rebleeding has occurred

6. Late Chronic stage –

cystic or collapsed with dense capsule

Vascular proliferation gradually forms fibrotic matrix with macrophage

Infants may resolve completely

Ferritin laden scar persists for years in adults

10% calc with residual hypodense focus in 40%

Gradient echo is helpful in detecting Haem in low field MRI’s

OVERVIEW OF HEMORRHAGE CAUSES

Underlying cause often hidden by the bleed. Intraventricular extension associated with 10% mortality

 

1. Neonatal Hemorrhage – germinal matrix hemorrhage secondary to prematurity

thin walled, proliferating vessels in subependyma of lateral caudothalamic groove

involution occurs at 34 wks when all cells have migrated

No hemorrhage in utero or beyond first 28 days post birth

 

Grade I – Hemorrhage confined to germinal matrix, can be bilateral

Grade II – rupture into normal size ventricles

Grade III – intraventricular hemorrhage with Hydrocephalus

Grade IV – extension to adjacent hemispheric white matter

Can be seen by US in acute & subacute, lucent if chronic

 

Term Infants – Hemorrhage usually secondary to trauma, subdural mostly

Asphyxia & infarction most commonly in non-traumatic cases

Posterolateral lentiform nuclei & ventral thalamus most susceptible

 

2. Hypertension – Most common cause of nontraumatic bleed in adult

Lenticulostriate & Pontine vasculatures mostly involved, penetrating branches of MCA

Usually spontaneous in elderly patients, basal ganglia mostly

Vessels often abnormal, ruptured microanuerysms etc

50% have hemorrhage dissection into ventricles, poor prognosis

Lobar white matter hemorrhage in 20%, cerebellum 10%, midbrain & brainstem rare

Originates along perforating branches near dentate nuclei

Active bleeding usually lasts <1hr

Edema progresses for 24-48hrs, 25% die in this period

Hypertensive Encephalopathy – occurs secondary to elevated BP

Toxemia (Most common) – autoregulation overwhelmed especially in posterior aspect

Overdistention of arteriole leads to BBB breakdown

Reversible vasogenic edema results, frank hemorrhage rare

Cortical petechia & subcortical hemorrhage possible, especially in occipital regions

Increased T2 in external capsule & basal ganglia more common

Chronic renal Diseases, TTP, & Hemolytic-Uremic syndrome other causes

 

3. Hemorrhagic Infarction

Arterial Infarction – hemorrhage when endothelium reperfused

Occurs in 50%, but only seen in 10%, sensitivity: MRI>CT

Cortex & basal ganglia from MCA distribution most commonly, 24-48hrs later

Pseudolaminar Cortical Necrosis – generalized hypoxia

Middle layers usually effected, gyriform hemorrhage

Nonhemorrhagic ischemic changes can occur, gyri calcification possible

Venous Infarction – usually associated with dural sinus thrombosis

Dura around sinus will enhance, clot stays hypodense (empty delta sign)

More likely to effect white matter than cortex

4. Aneurysms – 90% of nontraumatic subarachnoid hemorrhage

Headache common presenting sign for aneurysm, CT best for acute SAH

Blood usually fills ambient cisterns & sylvian first

90% of blood cleared from CSF in 1wk

MRI better for subacute or chronic SAH, dirty CSF

Superficial siderosis – hemosiderin deposit on meninges

Cerebellum brainstem & cranial nerves also coated – neurological dysfunction

Giant aneurysms >2.5cm often have intramural hemorrhage

most from carotid, cavernous portion most common, all ages

75% have calc if thrombosed, none otherwise

Charcot-Bushard Aneurysm – secondary to HTN

5. Vascular Malformations –

AVM & Cavernous Angioma commonly

Most bleed into parenchyma rather than subarachnoid space

Arteriovenous Malformation – pial, dural or mixed, No cap bed

Pial AVM’s – hemorrhage @ 2% per year, often in previously normal young pts

70% bleed by 1st exam, repeated hemorrhage can simulate neoplasm

Central nidus with gliosis & encephalomalacia

Dural AVM’s – no central nidus, SAH or subdural

hemorrhage rare unless drainage through cortical veins

 

Cavernous Angioma – bleed @ .5% per year, freq repeated bleeds

Popcorn like with mixed signal foci & hemosiderin ring

Venous Angiomas – bleed rare, similar hematoma of other malformations

Medusa like collection of dilated medullary veins

Capillary Telangiectasias – usually small & clinically silent

may see multiple small foci of hemosiderin on T2

INTRACRANIAL ANEURYSMS & VASCULAR MALFORMATIONS

Charcot-Bushard Aneurysm – secondary to Hypertension

20% multiple, higher incidence in females.

Look for familial causes such as Polycystic Kid Disease

 

SACCULAR ANEURYSMS

Berrylike out pouching from arterial bifurcation

Include intima & adventitia, media ends with normal vessel

1. Etiology – hemodynamic induced injury, abnormal shear forces most commonly

Trauma, infection, tumor, drug abuse & AV malformations

Berry Aneurysms – associated with polycystic kidney Diseases & aortic coarctation

2. Incidence – 1% of angios & 5% of postmortems

Multiple in 20%, esp in females & polycystic kidney Diseases

Bilateral in 20%, esp at cavernous sinus, Pcom & MCA trifurcation

Occur age 40-60 unless traumatic or mycotic,

 

3. Associated Conditions – occur at anomalous vessels & AVM

Inc pressure ie HTN & aortic coarctation

Systemic Diseases – Marfan’s, fibromuscular dysplasia, polycystic kidney diaeases

 

4. Location – 30% at anterior communicating, 30% at posterior communicating, 20% MCA origin

10% in post circulation especially basilar artery bifurcation

traumatic or mycotic occur anywhere

5. Clinical Presentation – asymptomatic until rupture or giant >2.5cm

1-2% risk of rupture per year, 3.5% risk of surg

No different risk with HTN, age, sex or multiplicity

All should be repaired if >3yr life expectancy

Subarachnoid Hem – clinical grade by Hunt & Hess scale I-V

Vasospasm most common cause of morbidity, 30% die

highest bleed rate in 1st 24hrs, 50% rebleed in 2wk

CT – shows SAH in >80% of ruptured aneurysms

Cavernous sinus aneurysms can compress Nerves III-VI

TIA, Seizures & embolic ischaemia less common

 

Giant Aneurysms – most from supraclinoid carotid, all ages

Fibrous vascular walls, rarely rupture, Symptoms secondary to mass effect

Partially Thrombosed Aneurysms – 75% have curvilinear calcification

CT most specific for these with target seen

NO calc if not thrombosed

D/D – Meningioma, both erode sella & lat sphenoid

aneurysm has no associated hyperostosis or atherosclerosis

 

6. Appearance of Saccular Type – catheter angiography definitive

asses for relation to vessel, adjacent branches & vasospasm

essential in assessment of nontraumatic SAH

Thrombosed aneurysm will have no finding, 15%

may see mass effect if large

irregularity or local vasospasm can indicate rupture

D/D vascular loops & infundibuli (embryonic funnel <2mm)

CT may show bone erosion in long standing case

Patent aneurysms enhance intensely w contrast

Location of SAH can be prognostic indicator

Ambient cisterns anterior to brainstem probably just venous rupture

No repeat angio needed

Suprasellar cistern to lateral sylvian fissure

more aneurysmal pattern, must do F/U angio

MRI dependent on pattern of flow, turbulence & clot

may have wall enhancement with gadodiamide, laminated with thrombosis

 

7. Traumatic Aneurysm –

nonpenetrating usually occur at skull base, or shear

hyperextention stretches ICA over lat C1

 

8. Mycotic Aneurysms – Secondary to infection of arterial wall, rare <10%

adventitia & muscularis disrupted, thoracic aorta commonly

Angio – occur dist to usual location, 2nd branch MCA commonly

most common cause of multiple MCA aneurysms

usually small, staph & strep most common, inc in child

bleed into parenchyma or SAH equal incidence

Medical Treatment usually sufficient to control, surgery if enlarge on angio

Mucor & Aspergilla invade direct from nasopharynx cause thrombosis & infarct more often than aneurysm

 

9. Oncotic Aneurysms – usually extra cranial, exsanguinate freq

tumor may implant or cause emboli, primary or metastatic

 

10. Flow-Related Aneurysms – seen with AVM’s in 30%

distal ones most likely to hemorrhage

 

11. Vasculopathies – rare but seen with SLE, infarct & TIA commonly

Takayasu’s Arteritis – 9:1 female, inflammation & stenosis most commonly

prox arch vessels, L subclavian commonly, often occludes

Fibromuscular Dysplasia – up to 50%, dissection & A-V fistula, 65% bilateral

Cocaine – 50% with CNS symptoms have SAH, may be secondary to HTN treatment

several drugs cause vasculitis .

 

FUSIFORM ANUERYSMS

Etiology – atherosclerosis, exaggerated arterial ectasia

media damaged, stretches & elongates, frequent mural thrombus

Vertebrobasilar Dolichoectasia – Common site, older patient

often thrombus producing brainstem infarcts

can also compress local stem causing nerve palsies

Imaging – enhances if patent, hyperintense if thrombosed

curvilinear calcification pathognomonic, may cause skull base erosion

 

DISSECTING ANEURYSMS

Etiology – intramural blood from tear in intima

may narrow or occlude lumen, may distend subadventitia

do not confuse with Pseudoaneurysm, a encapsulated hematoma

Presentation – usually extracranial unless severe trauma

Commonly in midcervical ICA & vertebral from C2 to skull base

Catheter angio remains procedure of choice for assesment

 

INTRACRANIAL VASCULAR MALFORMATIONS

1. Parenchymal AVM – congenital, dilated arteries & veins without capillary bed

98% solitary, multiple in Osler-Weber-Rendu & Wyburn-Mason

Incidence – 85% supratentorial, peak 20-40y, 25% children

Hemorrhage in 85% with 3% per year risk, seizure 25%, deficit 25%

Size not predictive, deeper & smaller ones bleed more

Parenchymal commonly, also common cause of SAH if

Vascular Steal – atrophy due to vasculopathy of feeding vessel

atrophic low density regions & hematoma with high density

Overlying meninges thick & hemosiderin stained

Angio – shows feeding arteries & tortuous veins

often wedge shaped, possible to appear Normal if thrombosed

GBM may simulate but usually has tissue between vessels

10% have aneurysms in feeding arteries, can bleed

 

Cryptic AVM’s – not seen by angio, 10%

CT – often absent w/o contrast, 25% have mild curvilinear calcification

mixed increased & decreased density if seen, Mild mass effect possible

Enlarged post venous sinuses but not cavernous sinus

Calcification seen in

MRI – honeycomb of flow voids, increased signal if thrombosed

hemorrhage in different stages often present

No significant intervening brain tissue, D/D : GBM

TX – resection if unruptured, must be completely removed

Aneurysms must be treated separately, increased risk for bleed

 

2. Dural AVM’s & Fistulae – form within a venous sinus

no discrete nidus, multiple microfistulae, occluding sinus frequent

Follow recanulation of thrombosed sinus, 10% of all AVM’s

Transverse or Sigmoid sinus commonly, Bruits & headache most common

Cavernous sinus AVM – proptosis, retro orbital pain, proptosis

SAH common if reflux flow forced into cortical veins

Carotid-Cavernous fistula related, follow trauma

Occipital & Meningeal branch of ext carotid #1 feeders

CT often N, MRI may show dilated cortical veins

 

3. Mixed – 15%, if parenchymal AVM recruits arteries from dural supply

 

4. Capillary Telangiectasias – multiple nests of dilated capillaries

Common in pons & Cerebellum, usually incidental

Gliosis of adjacent brain & hemosiderin staining from hem possibly

Cavernous Angiomas assoc or simply the extreme form

Osler-Weber-Rendu – hereditary hemorrhagic Telangiectasias

25% have brain abnormalities, most are true AVM’s

Visceral angio dysplasia with scalp & mucous membrane telangiectasia

2nd most common lesion to venous angioma at autopsy

Not visualized by angio, may present with epistaxis

CT may faintly enhance, faint on MRI

5. Cavernous Angiomas – Hemangioma or cavernoma

Circumscribed nodule of honeycomb sinusoidal vascular spaces

separated by fibrous bands but no intervening neural tissue

frequently MULTIPLE HEMATOMAS at different stages, reticulated core of vessels

Supratentorial 80% but can occur anywhere, 50% multiple

Most Common vascular lesion identified, 20-40y/o

Seizure, deficits & bleed most common presenting features

Angio does NOT visualize, possible faint blush in early venous

CT shows freq Calc, variable enhancement, can simulate neoplasm

MRI – popcorn like appearance on T2 due to multiple hem

multiple areas of signal drop-out due to hemosiderin

VENOUS MALFORMATIONS

1. Venous Angioma – dilated anomalous veins converge on central vein

Etiology – remnant embryonic venous system, usually solitary

assoc with migrational abnormalities & cavernous Angiomas in 30%

Asymptomatic, Hemorrhage very rare unless from associated cavernous angioma

CT – may show linear tuft of vessels post contrast

located in deep White Matter of cortex or Cerebellum, commonly adjacent to frontal horn

MRI – shows stellate tributary veins into prominent collector vein

gliosis or hemorrhage seen in only 15%

Angio – the only vascular malformation with a single draining vein

Medusa head appearance on venous phase of angio

 

2. Vein of Galen Aneurysm – enlargement of Galenic system

Secondary to arteriovenous fistulae from choroidal arteries

AVM in thalmus or midbrain can also cause this

Present at birth with high-out put cardiac failure, cranial bruit +

Macrocephaly with obstructive hydrocephalus, deficits & ocular symptoms

US shows bi-directional flow in vein of Galen

Angio demonstrates either choroidal artery or thalmoperforating feeder

dilation to venous varix with or without distal stenosis

if stenosed distally will often thrombose

CT – large enhancing midline mass posterior to 3rd ventricle

Hydrocephalus frequent but hemorrhage rare

enhancing serpentine vessels in thalamic region

3. Venous varix – assoc with several intracranial vascular abnormalities

Enlarged & thin veins resulting in SAH, hydrocephalus & increased ICP

Sinus Pericranii – venous haemangioma adherent to outer skull, deep to galea

supplied from intracranial sinus & blood returns to sinus

present with enlarging fluctuant soft tissue mass, enlarge with crying

often secondary to trauma, often resolved with prolonged compression

Frontal commonly, parietal next, most near sagittal sinus, can be very lateral

Skull Film – usually sharp margins, vascular honeycombs possible

CT – shows strong uniform enhancement

MRI – well delineated ovoid or fusiform areas variable signal

Venous Cavernoma – subcutaneous lesions of scalp

blood supply from external carotid, drain to external jugular

 

4. Orbital Venous Varix – rare vascular malformation in orbit

Causes intermittent proptosis & diplopia with valsalva & bending over

Disappear completely with axial views, use tourniquet on jugular vein

 

NEONATAL HEMORRAGE

Caudothalamic groove – between head of caudate & thalamus

both make up lateral wall of lateral ventricle, terminates in Monroe

Foramen of Monroe – divides frontal & body portions of ventricles

thalmus entirely posterior, caudate head anterior, choroid enters it

 

1. Subependymal Hemorrhage – preterm infants <32wks

Correlates with size of germinal matrix at birth, largest 24-32wks

involutes & is absent by 40wks, last in inferior lateral wall of frontal

lies inferior to ependyma, superior to head of caudate & anterior to thalmus

Usually occurs in first 3 days, always by 7-8 days

 

Grade 0 – Normal

Grade I – Subependymal alone

Grade II – intraventricular with no ventriculomegaly

Grade III – Hydrocephalus,

Grade IV – intraparenchymal

grade does not predict ultimate outcome, may progress

Serial studies required, only applies to germinal matrix hemorrhage

 

2. Parenchymal Hemorrhage – extends farther lateral than germinal matrix

can be “grade IV”, but not all secondary to germinal matrix bleed

most extend from SHE (Subependymal haemorrhage) to frontal or parietal lobes

Hypoxia & Hypercapnia implicated as etiology

stress causes vessels to dilate & burst

Phase 1 – echogenic like SEH for 1-2wks

Phase 2 – central Hypoechoic, bright peripheral rim 2-4wks

Phase 3 – retracts & settles into dependent position

Phase 4 – necrosis & phagocytosis complete, encephalomalacia

Cerebellar hematoma best scaned in coronal behind ear

assoc with mortality of 50%.

 

3. Choroidal Hemorrhage – usually grade II or III

Second cause of intraventricular hemorrhage not caused by SEH

Difficult to discern from normal choroid on US

asym scanning can show marked asym in choroid size

isolated choroid hematoma simulates ventricular hematoma with no hydrocephalus

Myelomeningocele assoc with pedunculated choroid

CT more reliable than US for Dx

D/D – Choroid Papilloma, very rare, consider if CSF clear on tap

all assoc with hydrocephalus, enhance intensely on CT

HEMORRHAGIC NEOPLASMS & CYSTS

 

1. Malignancy Related Coagulopathy – esp with leukemia & chemotherapy

systemic neoplasms can be assoc with term coagulopathy

 

2. Intratumoral Hematomas – 10%, malignant , Astrocytoma’s are most common.

Neovascularity, central necrosis, plasminogen activators etc contribute

Heterogeneous, incomplete hemosiderin ring, edema persist

multiple lesions & min edema suggests nonneoplastic cause

Cysts & slow growing cystic neoplasm like cranio rarely bleed

Oligodendroglioma, neuroectodermal & teratoma hemorrhage frequently

Ependymoma & choroid tumors – frequent SAH & hemosiderosis

Pituitary Adenoma – may bleed more frequently than astrocytoma

Lymphoma rarely bleed unless with AIDS

Renal cell Ca, chorio Ca, melanoma, thyroid & lung mets, 15%

 

3. Nonneoplastic Hemorrhagic Cysts -rare, colloid cysts never bleed

Rathke cleft cysts & Arachnoid cysts more commonly bleed

Arachnoid cysts bleed secondary to trauma, bridging vessels rupture

sometimes assoc with subdural hematoma

MISCELLANEOUS CAUSES OF BENIGN INTRACRANIAL HEMORRHAGE

1. Amyloid Angiopathy – Most common cause of bleed in elderly patient with no HTN

nonbranching fibrillar protiens form beta-pleated sheets

Deposit is Cortical & leptomeningeal vessels

extend from small vessels to brain parenchyma

Contractile elements replaced by the crystals

Multiple hematomas frequent & occurs at cortico medullary junction

basal ganglia & brainstem not affected

2. Infection & vasculitis – rare, increased chance if immuncompromised

septic emboli – mycotic aneurysms & hemorrhagic infarct

10% of Infective endocarditis have SAH or parenchymal

Aspergillosis & other fungi directly invade vessel

Thrombosis, infarction & hem result

Herpes Simplex II – the only encephalitis assoc with hematoma

 

3. Recreational Drugs – 50% have preexisting AVM or aneurysm

Cocaine can induce an acute hypertensive episode, vasospasm

also enhances platelet aggregation, dural sinus thrombosis

amphetamine & PCP also associated with hemorrhage

endothelial damage & necrotizing vasculitis

 

4. Blood Dyscrasias & Coagulopathies – iatrogenic or acquired

Vit K deficiency, hepatocellular diseases, antibody against clot, DIC

Anticoagulants, thrombolytics, aspirin, Etoh abuse, chemo

15% of all intracranial hemorrhage on anticoagulants

Supratentorial, intraparenchymal bleeds most common

 

 

 

Fwd: Paper Request

———- Forwarded message ———-
From: Atilla Çelik <dratillacelik@yahoo.com>
Date: Sun, Sep 21, 2008 at 3:43 PM
Subject: Paper Request
To: drhsdas@gmail.com

Dear Dr. Das.
I am Dr. Atilla Celik, from Istanbul, Turkey.
I am working at "Haydarpasa Numune Training & Research Hospital" as a General Surgeon.
I have seen your blog in recently. If it possible, I want to a copy of your published article that named "Large Adrenal Pseudocyst: Case Report with Review of Literature" in PDF format because of to cited our article "Laparoscopic management of giant adrenal cyst : Case report".
Best wishes from Turkey.
Dr. Atilla Celik.
General Surgeon.
Haydarpasa Numune Training & Research Hospital
2nd Department of General Surgery
Istanbul, Turkey.
+90 216 5652728 (Home)
+90 532 4865625 (Cell)
 

MOYA-MOYA SYNDROME

MOYA – MOYA SYNDROME

Moyamoya is a Japanese term which translates in english to: “cloudof smoke” or “puff of cigarette smoking drifting in the air” and it has been used to define a classic angiographic appearance of multiple small intracranial vessels . Although described first in Japan in the 1950s this form of cerebrovascular disease is not limited to the Japanese population and has been reported sporadically all over the world with cases described in the United States, Europe, Australia and Africa. The incidence seems to be roughly one in a million people per year. There seem to be two definite peaks of incidence: children under 10 years old and adults in their third to fifth decades of life. A slight female preponderance has been shown. There is some evidence of familial tendency based on association between moyamoya and certain HLA types. Familial incidence is estimated about 7 to 12% around the world.
The Moya moya pattern of vessels seen on angiography is thought to be a phenomena secondary to intracranial large vessel narrowing or stenosis. The response of the cerebral vasculature to this type of narrowing is for more distal vessels to proliferate. There is debate as to whether the vascular abnormality represents a congenital problem or an acquired stenosis of intracranial vessels that occurs early in life. Moyamoya type changes have been found in a variety of diseases, including sickle-cell disease, neurofibromatosis, trisomy 21 and fibromuscular dysplasia. Other predisposing conditions for this problem include an auto immune process, cranial trauma, anaerobic bacteria or the use of oral contraceptive but none has been convincing. There are no specific symptoms or signs related to moyamoya syndrome. The various clinical manifestations are generally caused by cerebrovascular ischemic or hemorrhagic events. Headaches and seizures are also seen. Clinically the disorder presents in children with transient ischemic attacks (TIA) frequently with episodes of hemiparesis or other focal neurological signs, often precipitated by physical exercise or hyperventilation. There may be a more chronic course of worsening with a gradual impairement of intellectual deterioration. Adults in contrast, usually present with intracerebral hemorrhage, most frequently in the thalamus, basal ganglia or deep white matter. Subarachnoid or intraventricular hemorrhage may also be observed. Other signs and symptoms seen in children and adults are disturbance of consciousness, speech disturbance, sensory impairment, involuntary movement and visual disturbance. The prognosis of moyamoya is difficult to predict because the natural history of the disease is still unclear. Autopsy studies have shown severe vascular occlusive changes in the intracranial portion of the ICA usually bilateral and in the main arteries that make up the circle of Willis. These changes are characterized by endothelial hyperplasia and fibrosis with intimal thickening and abnormalities of the internal elastic lamina, while the adventitia and media remain normal. Descriptions of the vertebrobasilar system are not available. Extracranial arteries at the level of heart, kidney and other organs may show the same intimal lesions as the intracranial arteries supporting the belief the moyamoya syndrome can be a more generalized systemic vascular syndrome. Inflammatory cells or atheroma are not typically seen. The intracerebral perforating arteries around the circle of Willis show micro aneurysm formation with fibrin deposition and thinning of the vessel wall. These types of changes are thought to be responsible for the occurrence of intracerebral hemorrhage. It is postulated that there is increased blood flow through these small fragile vessels making them prone to hemorrhage.Cerebral angiography is the cornerstone of the diagnosis of moyamoya syndrome. The characteristic angiographic findings of moyamoya syndrome are a symmetrical stenosis (tapering) or occlusion of the intracranial internal carotid artery, as well as the origin of the anterior and middle cerebral artery associated with an enlargement of the basal penetrating branches of these arteries in an apparent attempt to provide collateral circulation and giving the classic “cloud of smoke” appearance . Computed tomography scaning shows non specific findings. There may be ischemic areas of the cortex and sub cortical white matter with evidence of old areas of infarction. There may be mild ventricular dilatation or dilated sulci and fissures. In the case of intracerebral hemorrhage the CT scan will show the location of the intraventricular, subarachnoid nd intraparenchymal hemorrhage that usually occurs in the basal ganglia or thalamus .Magnetic resonance imaging may better visualize areas of cerebral infarction due to moyamoya. Usually these infarctions are multiple, small and asymptomatic.
Infarction is seen predominantly in the watershed areas of the carotid circulation at the borderzone between the areas of the brain supplied by the middle cerebral artery and anterior cerebral artery.Magnetic resonance angiography (MRA) can be used to detect the abnormal intracranial vessels although its resolution does not yet allow the visualization of the abnormal basal penetrating vessels. Other techniques including positron emission computed tomography(PET), single photon emission computed tomography (SPECT) and perfusion MRI studies have been used to study regional cerebral blood flow in moyamoya patients. There are still not enough available data to draw any conclusion about the usefulness of these techniques in the diagnosis of this condition. Transcranial Doppler has recently been used to study patients with moyamoya syndrome and has been shown to be a very useful non invasive technique to follow changes in larger vessels with time. The best treatment is not known. The treatment of moya moya patietns depends on the pattern of symptoms. For patients with ischemic events and infarction, medical therapy consists of management with steroids in certain instances. Aspirin, ticlopidine and occasionally vasodilators and anticoagulants may be used. No study has supported the definitive efficacy of any medical treatment. A variety of different surgical revascularisation procedures have been used, but whether they improve the outcome is not yet known. Superficial temporal artery-middle cerebral artery bypass, encephalodurosynangiosis,omentum transplantation and cervical sympathectomy are options. The main purpose of surgical procedures is to provide additional collateral flow to an are of ischemic brain and therefore to prevent further damage. Encephalodurosynangiosis (EDAS) is performed with the intent to divert flow from the external carotid artery into the internal carotid artery system by applying branches of the superficial temporal artery or the temporal muscle to the brain surface of a patient. Finally omentum transplantation is performed with the intent to revascularize ischemic tissue. Cervical sympathectomy including stellate ganglionectomy is performed with the intent of improving cerebral blood flow. For treatment of hemorrhage, hematoma evacuation and ventricular drainage are the usual methods of treatment. There is no specific medical or surgical therapy proven to reduce subsequent hemorrhage. Some patients with moyamoya stabilize clinically, often after they have developed disabilities, others continue to show progressive deterioration despite treatment.Although no definite effective treatment has been determined, surgical therapy to augment collateral circulation appears to be a promising treatment for patients with relapsing ischemic events.