Advanced CT of Stroke

1
Advanced CT of Stroke

• Lawrence N. Tanenbaum, M.D. FACR
• New Jersey Neuroscience Institute
• Seton Hall School of Graduate Medical Education
• Edison Imaging - JFK Medical Center
• www.drtmasters.com drt_at_drtmasters.com
• Edison, New Jersey

2
Head CTsingle channel technique

• axial scan 3 mm, 7 mm, 21 DFOV
• posterior fossa 140 kV, 340 mA, 1 sec
• supratentorial 120 kV, 280 mA, 1 sec
• convexity 120 kV, 200 mA, 1 sec
• helical (0.8 sec) in uncooperative patients

3
Detector cluster configurations
4
Multidetector slip-ring scannermultichannel (X)
system

• scan techniques
• multi-slice (X) step and shoot
• up to X slices per scan
• helical (volumetric / spiral)
• X detector clusters per scan

5
Multi-slice helicalvolumetric data set

• slice thickness, position and interval adjustable
• slice merge
• share data across clusters to merge slices
• scan thin, view thick
• reduce beam hardening (partial volume) artifact
• 1.25 mm posterior fossa head

6
Multi-slice helicalvolumetric data set

• slice thickness, position and interval adjustable
• slice merge
• share data across clusters to merge slices
• scan thin, view thick
• manage image number, patient dose, image noise

1.25 mm
2.5 mm
7
Head CT 4-8 slice axial

• post fossa 2 x 2.5 mm (1.25)
• 140 kV, 380 mA, 1sec
• supratentorial 2 x 5mm (2.5)
• 140kV, 350mA, 0.7 sec
• angle to avoid lens
• split to 1.25 / 2.5 for reformatting, 3D
• FOV 21, GSE 1, S 1

8
Head CT16 channel axial

• post fossa 4 x 2.5 mm (.625)
• 140 kV, 100/335 mA, 1sec
• supratentorial 4 x 5 mm (1.25)
• 140kV, 100/335 mA, 0.8 sec
• angle to avoid lens
• split to .625 / 1.25 for reformatting, 3D
• FOV 21, GSE 1, S 1

9
microvoxel volume acquisition
10
(No Transcript)
11
CT of Stroke
12
Thrombolysisexclusion criteria

• presence of hemorrhage (on CT)
• more than 3 hours since symptom onset
• major hemispheric infarction
• more than 1/3 of a vascular territory

Kumamoto 2000
ECAS
13
Hyperacute infarction
35 minutes
14
CT of acute infarction
Kumamoto 2000

• insular ribbon sign
• obscuration of lentiform nucleus
• hyperdense artery (MCA)
• hypodensity
• mass effect

Tomura, Radiology 1988, Truwit, Radiology 1990
15
right hemispheric ischemia
Tokyo 2001
16
Rio de Janeiro 2002
17
right hemispheric ischemia
Tokyo 2002
18
Orlando 2001
19
Vail 2003
20
Intra-arterial thrombolysis
Neil Borden, M.D.
21
left hemispheric ischemia
22
hyperdense MCA
23
OLIVE MIP
CTA
24
volume rendering
25
left hemispheric ischemia
26
(No Transcript)
27
(No Transcript)
28
(No Transcript)
29
(No Transcript)
30
(No Transcript)
31
(No Transcript)
32
Intra-arterial thrombolysis
Neil Borden, M.D.
33
(No Transcript)
34
(No Transcript)
35
(No Transcript)
36
(No Transcript)
37
CT Angiography arch to Circle of Willis 4
channel

• 1.25 mm cuts, overlap q 1 mm
• neck pitch 1.5 (6)
• 1.25 mm / 7.5 mm/rev
• 120 kV, 380 mA, 0.5 sec
• brain pitch .75 (3)
• 1.25 mm / 3.75 mm/rev
• 12w0 kV, 380 mA, 0.7 sec
• SmartPrep left ventricle
• 12 sec prep delay
• right arm1

1Barmeir et al AJR 170, June 1978, 1657-8
38
CT Angiography arch to Circle of Willis
8 channel

• 1.25 mm cuts, overlap q .8 mm
• neck
• pitch 1.35 (10.8)
• 1.25 mm / 13.5 mm/rev
• 120 kV 380 mA 0.5 sec
• brain
• pitch .625 (5)
• 1.25 mm / 6.25 mm/rev
• 120 kV 380 mA 0.7 sec
• SmartPrep left ventricle
• 12 sec prep delay
• right arm1

1Barmeir et al AJR 170, June 1998, 1657-8
39
CT Angiography arch to Circle of Willis
16 channel

• neck pitch 1.375 (22)
• .625 mm / .5 mm
• 17.5 mm/rev
• 120 kV 100/700 mA 0.4 sec
• brain pitch .5625 (9)
• .625 mm / .5 mm
• 5.63 mm/rev
• 120 kV 200/700 mA 1 sec
• SmartPrep left ventricle
• inject right arm1 (saline flush?)

1Barmeir et al AJR 170, June 1998, 1657-8
40
CT Angiography arch to Circle of Willis
64 channel

• neck pitch .984
• .625 mm / .5 mm
• 39 mm/rev (64 ch)
• 120 kV 200/800 mA 0.4 sec (NI 6)
• brain pitch .531
• .625 mm / .5 mm
• 10.62 mm/rev (32 ch)
• 120 kV 200/800 mA .4 sec (NI 6)
• SmartPrep left ventricle
• right arm1

1Barmeir et al AJR 170, June 1998, 1657-8
41
(No Transcript)
42
140 kV 91 mAs
dose modulation
140 kV 68 mAs
140 kV 55 mAs
140 kV 230 mAs
140 kV 230 mAs
43
CT Angiography
SmartPrep
44
Intravenous contrast

• Head (standard dose) 37 grams (370 / 100)
• Neck, orbit 23 grams (300 / 75)
• CT angiography 18 grams (370 / 50)
• CTA / PCT 37 grams (370 / 60-40)
• TR CTA /PCT 18 grams (370 / 50)

45
CT angiographydisplay methods

• shaded surface display
• maximum intensity projection
• ray sum (summed intensity) projection
• OLIVE MIP / MPVR
• volume rendering

ICA occlusion
46
CT Angiography OLIVE MIP

• 3 plane MPR
• 20 mm thick MIP
• 2 mm intervals
• FOV 14

Steamboat 2003
47
16 x .625 mm
OLIVE MIP
48
OLIVE MIP
49
24 7 CTA
OLIVE MIP
Verro P, Tanenbaum LN, Borden NM, Eshkar NE, Sen
S CT Angiography in Acute Ischemic Stroke.
Stroke 2002, Jan 33(1) 276-278.
50
(No Transcript)
51
(No Transcript)
52
Neil Borden, MD
53
Intraarterial thrombolysis
54
right hemispheric ischemia
55
(No Transcript)
56
Rio de Janeiro 2002
57
left hemispheric ischemia
58
Perfused blood volume
59
(No Transcript)
60
(No Transcript)
61
(No Transcript)
62
(No Transcript)
63
(No Transcript)
64
(No Transcript)
65
(No Transcript)
66
(No Transcript)
67
(No Transcript)
68
(No Transcript)
69
(No Transcript)
70
(No Transcript)
71
(No Transcript)
72
Perfused blood volumetechnique

• reformat images from CTA study obtained during
  power injection of contrast
• 3 mm thickness
• 1.5 mm interval
• 90 WW 40 WL
• 19 FOV
• more sensitive than non contrast CT for acute CVA

73
(No Transcript)
74
(No Transcript)
75
New Jersey 2001
76
MRI / MRA
77
First pass perfusion
CBF
MTT
CBV
78
Perfusion imagingprinciples
CT
MR

• monitor the first pass of a rapid bolus injection
  of a standard iodine / gadolinium contrast agent
  through the cerebral vasculature
• contrast bolus causes a transient rise in
  attenuation (CT) or decrease in signal (MR)
  proportional to the amount of tracer in a given
  region
• integration of data over the time course of the
  first pass of the contrast agent allows creation
  of map of brain perfusion

79
Perfusion MRI
Left MCA ischemia
80
Perfusion imagingtechnique
SLE

• single shot spin echo EPI
• TR 1900
• TE 80
• FOV 30 x 19
• 192 x 128
• 35 phases, 11 locs, 67 seconds

81
Perfusion imagingtechnique

• initiate single-shot SE EPI series
• power inject Gd at 0.1-0.2 mmol/kg at 3 cc/sec
  after 8 sec delay
• process data on scanner console
• technologist creates map of whole brain dynamic
  susceptibility contrast

82
radiation
83
MR perfusionchallenges

• universal 24 / 7 ready access
• technical factors limit quantitation of
  CBF, tissue viability
• ?input function?
• ?commercial availability/validation of gamma
  variate/deconvolution software?

Giessen 2000
84
CT Perfusion
MTT
CBF
CBV
85
CT Perfusionimaging technique

• identify slice/ slices covering three vascular
  territories
• inject 40 cc of 370 (400) _at_4 cc/sec (saline
  flush)
• 45 second scan, 5 sec prep delay
• 80 kVp, 190 mAs
• process data on scanner console or workstation

86
CT Perfusionimaging technique

• identify slice/ slices covering three vascular
  territories
• inject 40 cc of 370 (400) _at_4 cc/sec.
• 45 second scan, 5 sec prep delay
• 80 kVp, 190 mAs
• process data on workstation

87
(No Transcript)
88
Perfusion CT
user interface
89
CT Perfusion
automatic artery / vein identification
90
Volume CTbenefits of longer detector
64 cells of 0.625 mm 40 mm coverage thin

• 40 mm detector extends coverage for static table
  dynamic applications
• perfusion
• time resolved neuro CTA

40 mm
64 X 0.625
91
CT Perfusion

• CBV (ml / 100 g of tissue)
• PEI normalized for the pixel value of blood
  (vein)
• MTT (sec)
• deconvolution of the time course data (first
  moment) of arterial ROIs
• CBF (ml / 100g of tissue / min)
• rCBV / MTT

92
Dr. Reto Meuli Lausanne Suisse
CBF
Xenon CT
Perfusion CT
Wintermark M, et. Al AJNR 22905, May 2001
93
Perfusion CTvalidation studies

• Cenic A, Nabavi DG, Craen RA, Gelb AW, Lee T-Y.
  Dynamic CT measurement of cerebral blood flow A
  validation study. AJNR 1999 2063-73.
• Nabavi DG, Cenic A, Craen RA, Gelb AW, Bennett
  JD, Kozak R, Lee T-Y. CT assessment of cerebral
  perfusion Experimental validation and initial
  clinical experience. Radiology 1999 213141-149.

94
Perfusion imagingrole in brain attack

• most accurately reflects the amount of tissue
  under ischemic conditions in the hyperacute
  period
• changes seen almost immediately after the
  induction of ischemia
• more sensitive than (CT/PBV CT,) DW MRI
• ischemic volume often more extensive than
  infarcted volume (CT, PBV CT) in early stroke
• PMR DWEPI (Na) tissue at risk / penumbra
• PCT low CBF/low CBV tissue at risk /
  penumbra?

95
Perfusion imagingfindings in infarction

• CBF
• decreased flow
• MTT
• regional prolongation of transit time
• CBV
• regional perfusion deficit
• compensatory increased volume

96
Acute CVA MR exam
FLAIR vs. Diffusion reveals acute infarct
Diffusion vs. DSC reveals tissue-at-risk
St. Lukes Hospital, Milwaukee, WI, Breger et al.
97
(No Transcript)
98
(No Transcript)
99
(No Transcript)
100
(No Transcript)
101
(No Transcript)
102
(No Transcript)
103
ICA occlusion
104
acute right hemispheric ischemic symptoms
105
(No Transcript)
106
CT Perfusion
PBV
CT
CBF
107
CT Perfusion
MTT
CBF
CBV
108
acute right hemispheric ischemia
D. Brasier, M.D. Australia
109
CT Perfusion
MTT
CBF
CBV
D. Brasier, M.D. Australia
110
(No Transcript)
111
(No Transcript)
112
right hemispheric ischemia
113
(No Transcript)
114
(No Transcript)
115
(No Transcript)
116
(No Transcript)
117
(No Transcript)
118
(No Transcript)
119
(No Transcript)
120
(No Transcript)
121
(No Transcript)
122
(No Transcript)
123
(No Transcript)
124
(No Transcript)
125
(No Transcript)
126
(No Transcript)
127
(No Transcript)
128
(No Transcript)
129
viability CBF
10
130
(No Transcript)
131
confusion
r/o CVA
132
(No Transcript)
133
(No Transcript)
134
Vail 2003
135
seizure vs. right hemispheric infarction
136
right hemispheric ischemia
Las Vegas 2000
137
(No Transcript)
138
(No Transcript)
139
PBV CT
140
MTT
CBF
CBV
141
CT Perfusion- r/o stroke
CBF
CBV
MTT
142
CT Perfusion- r/o stroke
5
6
7
10
11
4
3
8
9
12
143
post thrombolysis MCA occlusion
144
ICA occlusion
145
(No Transcript)
146
(No Transcript)
147
PBV
148
MTT
CBF
CBV
149
7
150
3
151
(No Transcript)
152
(No Transcript)
153
CT Perfusion
MTT
CBF
CBV
154
(No Transcript)
155
CBV
DWI
156
(No Transcript)
157
(No Transcript)
158
(No Transcript)
159
(No Transcript)
160
(No Transcript)
161
(No Transcript)
162
3
5
8
163
Acute CVA CT Protocol

• unenhanced CT
• CTA (PBV)
• 60cc of 370 contrast _at_ 4 cc/sec
• Perfusion
• acquisition at level of the basal ganglia
• 4-16 channel 4 x 5mm, 2 x 10mm
• 64 channel 4 x 10mm
• 40cc of 370 contrast _at_ 4 cc/sec
• ? Combined TR CTA perfusion?

164
MTT
CBV
CBF
165
right MCA stenosis
166
Perfusion CT
MTT
CBF
CBV
167
16 channel .625 mm
168
neuro CTA 16 x .625 mm
169
(No Transcript)
170
MCA stenosis
171
MCA stenosis
172
(No Transcript)
173
(No Transcript)
174
post Diamox
175
post Diamox
176
Perfusion CT functional assessment

• right ICA, MCA, ACA occlusion
• left ICA stenosis
• left M1 stenosis
• right A2 fills via left A2
• VB system normal

177
(No Transcript)
178
(No Transcript)
179
(No Transcript)
180
(No Transcript)
181
(No Transcript)
182
35 yr old acute left CVA
183
(No Transcript)
184
ICA dissection
MTT
CBF
CBV
185
(No Transcript)
186
Mean transit time
difference
before Diamox
after Diamox
T. Lee London, Ontario
187
Cerebral blood flow (rCBF)
before Diamox
after Diamox
difference
T. Lee London, Ontario
188
Cerebral blood volume (rCBV)
after Diamox
difference
before Diamox
T. Lee London, Ontario
189
Moya - moya
Diamox study
190
Moya-moya ischemia assessment
191
Moya-Moya Diamox study
192
STA- MCAbypass
M. Brandt-Zawadzki MD
193
STA to MCA bypass
MTT
CBF
CBV
M. Brandt-Zawadzki MD
194
(No Transcript)
195
(No Transcript)
196
r/o brain death
197
Intravenous contrastnon-ionic

• Head (standard dose) 40 grams (200 / 200)
• Neck, orbit 23 grams (300 / 75)
• CT angiography 37 grams (370 / 100)
• CTA / PCT 37 grams (370 / 60-40)

198
www.drtmasters.com drt_at_drtmasters.com
Chicago 2001
JFK Medical Center