Kamran M 1, Deuerling-Zheng 2, Mueller-Allissat B 2, Grunwald IQ 1, Byrne JV 1 1. Oxford Neurovascular and Neuroradiology Research Unit, University of Oxford, 2. Siemens AG, Healthcare, Forchheim, Germany Measurement of Cerebral Blood Volume using Dyna-CT: A Feasible Method for Assessment of Vasospasm Severity Following Aneurysmal SAH

Background Three dimensional volume Angiograms CT-like soft tissue images Image quality Image quality Contrast resolution Contrast resolution Spatial resolution Spatial resolution Temporal resolution Temporal resolution Detector efficiency Detector efficiency Mechanical properties Mechanical properties of C-arm gantry

Background Three dimensional volume Angiograms CT-like soft tissue images Image quality Image quality Contrast resolution Contrast resolution Spatial resolution Spatial resolution Temporal resolution Temporal resolution Detector efficiency Detector efficiency Mechanical properties Mechanical properties of C-arm gantry

Background Cerebral vasospasm following aneurysmal SAH An ideal technique for detection: ●Detect presence or absence of vasospasm before clinical deficits ●Be objective (reproducible) ●Effective in the unconscious patient ●Non-invasive

Background Cerebral vasospasm following aneurysmal SAH An ideal technique for detection: ●Detect presence of absence of vasospasm before clinical deficits ●Be objective (reproducible) ●Effective in the unconscious patient ●Non-invasive Diagnosis and assessment: ●Catheter angiography ●Transcranial Doppler Ultrasonography ●CT or MR perfusion scans

CBV measurement using C-arm FDCT Subtraction of the mask run from the contrast run Normalisation of parenchyma with an input function from major vessels CBV parametric maps Time Concentration Mask run Contrast run 8 seconds Steady state

C-arm FDCT Three dimensional volume

C-arm FDCT Three dimensional volume

Methods Dyna-CT ● CBV Scan parameters: Two 8-sec acquisitions (mask and contrast enhanced), approx. 400 projections each at 0.5° steps, fluoroscopic monitoring in between approx. 400 projections each at 0.5° steps, fluoroscopic monitoring in between ● Post-processing for CBV estimation: co-registration, subtraction, normalisation with an input function an input function ● Angiographic reconstructions: contrast enhanced run only, 512×512 matrix, smooth/sharp kernel smooth/sharp kernel MR scan ● MR-PWI, MR-DWI, Time of Flight MRA, T1, and T2 weighted sequences ● Perfusion scan: DSC, T2* weighted gradient echo planar sequence (20ml 0.5M Gadolinium based contrast material), TR~2000msec, TE 44msec, FOV 248×248mm, Gadolinium based contrast material), TR~2000msec, TE 44msec, FOV 248×248mm, 256×256 matrix, voxel size 0.98×0.98×4mm, 15 slices, 50 time-points 256×256 matrix, voxel size 0.98×0.98×4mm, 15 slices, 50 time-points ● Perfusion analysis: block-circulant SVD algorithm, AIF chosen semi-automatically, motion correction motion correction

Example case 1 A 60 year old lady presenting with ruptured anterior communicating artery aneurysm (5 × 7mm) ● Day 0: SAH, no loss of consciousness, Grade 1 ● Day 1: Coil embolisation, Grade 1 ● Day 3: Fluctuating LOC, numbness of the left arm and numbness of the left arm and leg, normal CT leg, normal CT ● Day 4: Weakness of both legs, neuro-ITU for supportive neuro-ITU for supportive therapy therapy MR-PWI and Dyna-CT scans MR-PWI and Dyna-CT scans Angioplasty Angioplasty

Example case 1 MR-PWI MTT Dyna-CT CBVMR-PWI CBV MR-DWI A 60 year old lady presenting with ruptured anterior communicating artery aneurysm (5 × 7mm) ● Day 0: SAH, no loss of consciousness, Grade 1 ● Day 1: Coil embolisation, Grade 1 ● Day 3: Fluctuating LOC, numbness of the left arm and numbness of the left arm and leg, normal CT leg, normal CT ● Day 4: Weakness of both legs, neuro-ITU for supportive neuro-ITU for supportive therapy therapy MR-PWI and Dyna-CT scans MR-PWI and Dyna-CT scans Angioplasty Angioplasty

Example case 1 MR-PWI MTT Dyna-CT CBVMR-PWI CBV MR-DWI A 60 year old lady presenting with ruptured anterior communicating artery aneurysm (5 × 7mm) ● Day 0: SAH, no loss of consciousness, Grade 1 ● Day 1: Coil embolisation, Grade 1 ● Day 3: Fluctuating LOC, numbness of the left arm and numbness of the left arm and leg, normal CT leg, normal CT ● Day 4: Weakness of both legs, neuro-ITU for supportive neuro-ITU for supportive therapy therapy MR-PWI and Dyna-CT scans MR-PWI and Dyna-CT scans Angioplasty Angioplasty R L

Example case 1 MR-PWI MTT Dyna-CT CBVMR-PWI CBV MR-DWI A 60 year old lady presenting with ruptured anterior communicating artery aneurysm (5 × 7mm) ● Day 0: SAH, no loss of consciousness, Grade 1 ● Day 1: Coil embolisation, Grade 1 ● Day 3: Fluctuating LOC, numbness of the left arm and numbness of the left arm and leg, normal CT leg, normal CT ● Day 4: Weakness of both legs, neuro-ITU for supportive neuro-ITU for supportive therapy therapy MR-PWI and Dyna-CT scans MR-PWI and Dyna-CT scans Angioplasty Angioplasty R L

Example case 2 A 41 year old man presenting with ruptured anterior communicating artery aneurysm (6×4.5mm) ●Day 0: SAH, Grade 1 ●Day 6: Reached hospital. CT scan ●Day 7: Dysphasia and right sided hemiplegia; neuro-ITU for supportive therapy. Deficits recovered. CTA showed an Acom (6x4.5x5 mm) and a left MCA (3x3.5x3 mm) aneurysm. ● Day 7: Coil embolisation of both aneurysms. Vasospasm of ACA and MCA ●Day 8: Deteriorating LOC, dysphasia, and weakness of right side of the body. CT, MR-PWI scan CT, MR-PWI scan Dyna-CT CBV Angioplasty (Nimodipine)

Example case 2 A 41 year old man presenting with ruptured anterior communicating artery aneurysm (6×4.5mm) ●Day 0: SAH, Grade 1 ●Day 6: Reached hospital. CT scan ●Day 7: Dysphasia and right sided hemiplegia; neuro-ITU for supportive therapy. Deficits recovered. CTA showed an Acom (6x4.5x5 mm) and a left MCA (3x3.5x3 mm) aneurysm. ● Day 7: Coil embolisation of both aneurysms. Vasospasm of ACA and MCA ●Day 8: Deteriorating LOC, dysphasia, and weakness of right side of the body CT, MR-PWI scan CT, MR-PWI scan Dyna-CT CBV Angioplasty (Nimodipine)

Example case 2 A 41 year old man presenting with ruptured anterior communicating artery aneurysm (6×4.5mm) ●Day 0: SAH, Grade 1 ●Day 6: Reached hospital. CT scan ●Day 7: Dysphasia and right sided hemiplegia; neuro-ITU for supportive therapy. Deficits recovered. CTA showed an Acom (6x4.5x5 mm) and a left MCA (3x3.5x3 mm) aneurysm. ● Day 7: Coil embolisation of both aneurysms. Vasospasm of ACA and MCA ●Day 8: Deteriorating LOC, dysphasia, and weakness of right side of the body CT, MR-PWI scan CT, MR-PWI scan Dyna-CT CBV Angioplasty (Nimodipine)

Example case 2 A 41 year old man presenting with ruptured anterior communicating artery aneurysm (6×4.5mm) ●Day 0: SAH, Grade 1 ●Day 6: Reached hospital. CT scan ●Day 7: Dysphasia and right sided hemiplegia; neuro-ITU for supportive therapy. Deficits recovered. CTA showed an Acom (6x4.5x5 mm) and a left MCA (3x3.5x3 mm) aneurysm. ● Day 7: Coil embolisation of both aneurysms. Vasospasm of ACA and MCA ●Day 8: Deteriorating LOC, dysphasia, and weakness of right side of the body CT, MR-PWI scan CT, MR-PWI scan Dyna-CT CBV Angioplasty (Nimodipine) R L

ROIs analysis

Results Grey matter r = % limits of agreement = to Measurement bias = 0.03 White matter r = % limits of agreement = to Measurement bias = -0.01

Results Grey matter r = % limits of agreement = to Measurement bias = 0.03 White matter r = % limits of agreement = to Measurement bias = -0.01

Results Overall(GM+WM) r = % limits of agreement = to Measurement bias = 0.02 Radiographic contrast: 80ml of Niopam 370 Radiation dose: 1.78 mSv Scan time: ~25 sec

Conclusion Dyna-CT CBV agree with MR-PWI CBV Dyna-CT CBV agree with MR-PWI CBV Improved spatial resolution, short scanning time, complete brain coverage Improved spatial resolution, short scanning time, complete brain coverage Exploits the same data to generate angiographic and soft tissue images (with reduced contrast and radiation dose) Exploits the same data to generate angiographic and soft tissue images (with reduced contrast and radiation dose) Potentially useful tool that may help in time efficient triage of patients with brain ischaemia in optimized interventional environment Potentially useful tool that may help in time efficient triage of patients with brain ischaemia in optimized interventional environmentHowever, Improvements in detector efficiency and gantry rotation speeds are warranted to exploit its soft tissue and perfusion imaging potential Improvements in detector efficiency and gantry rotation speeds are warranted to exploit its soft tissue and perfusion imaging potential

Acknowledgements Department of Neuroradiology, West Wing, JR Hospital, Oxford Department of Neuroradiology, West Wing, JR Hospital, Oxford The Rhodes Trust The Rhodes Trust Siemens AG Healthcare, Forchheim Germany Siemens AG Healthcare, Forchheim Germany Many Thanks ! Many Thanks !