Answer for BIR CoW 01 Nov 2020
AVM
IMAGING FINDINGS
Plain CT Brain - Ill-defined lobulated cortical based mass lesion in the right parieto-occipital region with curvilinear cortical calcifications. Parenchymalhematoma noted adjacent to the lesion extending into the right medial occipital lobe. Mass effect over trigone of right lateral ventricle and midline shift of towards the left side. MRI Brain – Multiple serpiginous flow voids with few adjoining calcific specks/ subcortical hemosiderin deposits in right parieto-occipital region.There is adjoining minimal vasogenicedema and mass effect with compression of right lateral ventricle occipital horn and posterior body.Late subacute hematoma in right occipital region. MRA - Arterial feeders noted from right posterior cerebral artery (P4 segment).Few arterial twigs from distal branches of right M4 segment also noted supplying lesion. MRV - Venous drainage from lesion is noted into right internal cerebral vein and the posterior superior sagittal sinus. CT Angiogram - Major Arterial feeders noted from right posterior cerebral artery (P4 segment). Few arterial twigs from distal branches of right M4 segment and pericallosal branches of right anterior cerebral artery also noted supplying lesion. There is early venous drainage into right internal cerebral vein and the posterior superior sagittal sinus. Engorged venous channels / Intranidal venous aneurysms noted,measuring 1.2 cms. The Nidus appears compact and measures 5.2 cms.
DISCUSSION
Brain AVMs are abnormal connections between arteries that would normally supply the brain tissue (pial vessels) and veins that normally drain the brain, resulting in arteriovenous shunting with an intervening network of vessels within the brain parenchyma and lack of a true capillary bed. The transition between artery and vein can take place via a nidus (a tangle of abnormal vessels located in the brain parenchyma). The diagnostic criteria include (a) the presence of a nidus embedded within the brain parenchyma (b) early venous drainage, Two subtypes of nidus can be encountered. The typical type is the glomerular or compact type nidus, which consists of abnormal vessels without any interspersed normal brain tissue. The more rarely seen second type is the proliferative type nidus, in which normal brain parenchyma is interspersed throughout the tangle of vessels. SPETZLER MARTIN GRADING - allocates points for various features of intracranial arteriovenous malformations to give a grade between 1 and 5. Grade 6 is used to describe inoperable lesions. The score correlates with operative outcome. • size of nidus o small (<3 cm) = 1 o medium (3-6 cm) = 2 o large (>6 cm) = 3 • eloquence of adjacent brain o non-eloquent = 0 o eloquent = 1 • venous drainage o superficial veins only = 0 o deep veins = 1 Eloquence of adjacent brain • eloquent brain o sensorimotor, language, visual cortex, hypothalamus, thalamus, brain stem, cerebellar nuclei, or regions immediately adjacent to these structures • non-eloquent brain o frontal lobe, temporal lobe, cerebellar hemispheres RISK OF HEMORRHAGE – Previous haemorrhage Intranidal aneurysm Venous ectatsia Deep venous drainage Single venous drainage Deep or posterior fossa location
Differential diagnosis
Imaging differential considerations include: o cerebral proliferative angiopathy absence of early venous drainage often, an entire lobe or even hemisphere is affected feeder arteries tend to be of normal size or moderately enlarged associated stenosis of feeder arteries is often present o craniofacial arteriovenous metameric syndrome (CAMS): classic locations association with facial AVM o dural arteriovenous fistula (DAVF) o developmental venous anomaly (DVA) • vascular tumor • glioblastoma
REFERENCES:
1) Geibprasert S, Pongpech S, Jiarakongmun P et-al. Radiologic assessment of brain arteriovenous malformations: what clinicians need to know.Radiographics. 30 (2): 483-501.
2) Spetzler RF, Martin NA. A proposed grading system for arteriovenous malformations. J. Neurosurg. 1986;65 (4): 476-83.
IMAGING FINDINGS
Plain CT Brain - Ill-defined lobulated cortical based mass lesion in the right parieto-occipital region with curvilinear cortical calcifications. Parenchymalhematoma noted adjacent to the lesion extending into the right medial occipital lobe. Mass effect over trigone of right lateral ventricle and midline shift of towards the left side. MRI Brain – Multiple serpiginous flow voids with few adjoining calcific specks/ subcortical hemosiderin deposits in right parieto-occipital region.There is adjoining minimal vasogenicedema and mass effect with compression of right lateral ventricle occipital horn and posterior body.Late subacute hematoma in right occipital region. MRA - Arterial feeders noted from right posterior cerebral artery (P4 segment).Few arterial twigs from distal branches of right M4 segment also noted supplying lesion. MRV - Venous drainage from lesion is noted into right internal cerebral vein and the posterior superior sagittal sinus. CT Angiogram - Major Arterial feeders noted from right posterior cerebral artery (P4 segment). Few arterial twigs from distal branches of right M4 segment and pericallosal branches of right anterior cerebral artery also noted supplying lesion. There is early venous drainage into right internal cerebral vein and the posterior superior sagittal sinus. Engorged venous channels / Intranidal venous aneurysms noted,measuring 1.2 cms. The Nidus appears compact and measures 5.2 cms.
DISCUSSION
Brain AVMs are abnormal connections between arteries that would normally supply the brain tissue (pial vessels) and veins that normally drain the brain, resulting in arteriovenous shunting with an intervening network of vessels within the brain parenchyma and lack of a true capillary bed. The transition between artery and vein can take place via a nidus (a tangle of abnormal vessels located in the brain parenchyma). The diagnostic criteria include (a) the presence of a nidus embedded within the brain parenchyma (b) early venous drainage, Two subtypes of nidus can be encountered. The typical type is the glomerular or compact type nidus, which consists of abnormal vessels without any interspersed normal brain tissue. The more rarely seen second type is the proliferative type nidus, in which normal brain parenchyma is interspersed throughout the tangle of vessels. SPETZLER MARTIN GRADING - allocates points for various features of intracranial arteriovenous malformations to give a grade between 1 and 5. Grade 6 is used to describe inoperable lesions. The score correlates with operative outcome. • size of nidus o small (<3 cm) = 1 o medium (3-6 cm) = 2 o large (>6 cm) = 3 • eloquence of adjacent brain o non-eloquent = 0 o eloquent = 1 • venous drainage o superficial veins only = 0 o deep veins = 1 Eloquence of adjacent brain • eloquent brain o sensorimotor, language, visual cortex, hypothalamus, thalamus, brain stem, cerebellar nuclei, or regions immediately adjacent to these structures • non-eloquent brain o frontal lobe, temporal lobe, cerebellar hemispheres RISK OF HEMORRHAGE – Previous haemorrhage Intranidal aneurysm Venous ectatsia Deep venous drainage Single venous drainage Deep or posterior fossa location
Differential diagnosis
Imaging differential considerations include: o cerebral proliferative angiopathy absence of early venous drainage often, an entire lobe or even hemisphere is affected feeder arteries tend to be of normal size or moderately enlarged associated stenosis of feeder arteries is often present o craniofacial arteriovenous metameric syndrome (CAMS): classic locations association with facial AVM o dural arteriovenous fistula (DAVF) o developmental venous anomaly (DVA) • vascular tumor • glioblastoma
REFERENCES:
1) Geibprasert S, Pongpech S, Jiarakongmun P et-al. Radiologic assessment of brain arteriovenous malformations: what clinicians need to know.Radiographics. 30 (2): 483-501.
2) Spetzler RF, Martin NA. A proposed grading system for arteriovenous malformations. J. Neurosurg. 1986;65 (4): 476-83.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!