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Cerebral Perfusion CT: Technique and Clinical Applications¹

¹ From the Departments of Radiology (E.G.H., I.C., R.J., S.K.G., G.V.S., J.P.D., R.C.C., S.K.M.) and Neurosurgery (B.G.T., M.R.H.), University of Michigan Health System, 1500 E Medical Center Dr, University Hospital B2 A209, Ann Arbor, MI 48109. Received November 14, 2002; revision requested January 17, 2003; revision received March 21; accepted May 1. Address correspondence to E.G.H. (e-mail: hoeffner@umich.edu).

View larger version (111K): [in a new window]   Figure 1a. (a) Transverse CT image obtained during contrast agent administration and (b) time-concentration curves in a healthy adult volunteer. (a) A branch of the anterior cerebral artery (ACA) is chosen as the input artery (white arrow) and the torcular herophili is chosen as the input vein (black arrow). (b) Time-concentration curves are generated for the input artery (green line) and vein (red line).

View larger version (29K): [in a new window]   Figure 1b. (a) Transverse CT image obtained during contrast agent administration and (b) time-concentration curves in a healthy adult volunteer. (a) A branch of the anterior cerebral artery (ACA) is chosen as the input artery (white arrow) and the torcular herophili is chosen as the input vein (black arrow). (b) Time-concentration curves are generated for the input artery (green line) and vein (red line).

View larger version (131K): [in a new window]   Figure 2a. Transverse CT perfusion maps in a healthy adult volunteer show normal perfusion. Various color ramps, selected according to user preference, are used to display the (a) CBF, (b) CBV, and (c) MTT maps.

View larger version (134K): [in a new window]   Figure 2b. Transverse CT perfusion maps in a healthy adult volunteer show normal perfusion. Various color ramps, selected according to user preference, are used to display the (a) CBF, (b) CBV, and (c) MTT maps.

View larger version (130K): [in a new window]   Figure 2c. Transverse CT perfusion maps in a healthy adult volunteer show normal perfusion. Various color ramps, selected according to user preference, are used to display the (a) CBF, (b) CBV, and (c) MTT maps.

View larger version (120K): [in a new window]   Figure 3a. Transverse (a) CT image and (b) CBF map in a healthy adult volunteer, with circular ROIs (in purple) in place. Identical ROIs appear on CBV and MTT maps (not shown).

View larger version (151K): [in a new window]   Figure 3b. Transverse (a) CT image and (b) CBF map in a healthy adult volunteer, with circular ROIs (in purple) in place. Identical ROIs appear on CBV and MTT maps (not shown).

View larger version (116K): [in a new window]   Figure 4a. Acute infarction in a 76-year-old woman who was unresponsive. (a) Initial transverse head CT image shows subtle hypoattenuation (arrows) in left insula, temporal lobe, and frontal lobe. (b) Transverse CBF map shows decreased CBF (arrows) in left ACA and anterior MCA territories, with quantitative values as low as 11 mL/100 g/min. (c) Transverse CBV map shows decreased CBV (arrows). (d) Transverse MTT map shows slightly elevated MTT (arrows). Changes are consistent with infarction. (e) Follow-up transverse CT image shows large infarct (arrows) in left ACA and MCA territories.

View larger version (112K): [in a new window]   Figure 4b. Acute infarction in a 76-year-old woman who was unresponsive. (a) Initial transverse head CT image shows subtle hypoattenuation (arrows) in left insula, temporal lobe, and frontal lobe. (b) Transverse CBF map shows decreased CBF (arrows) in left ACA and anterior MCA territories, with quantitative values as low as 11 mL/100 g/min. (c) Transverse CBV map shows decreased CBV (arrows). (d) Transverse MTT map shows slightly elevated MTT (arrows). Changes are consistent with infarction. (e) Follow-up transverse CT image shows large infarct (arrows) in left ACA and MCA territories.

View larger version (108K): [in a new window]   Figure 4c. Acute infarction in a 76-year-old woman who was unresponsive. (a) Initial transverse head CT image shows subtle hypoattenuation (arrows) in left insula, temporal lobe, and frontal lobe. (b) Transverse CBF map shows decreased CBF (arrows) in left ACA and anterior MCA territories, with quantitative values as low as 11 mL/100 g/min. (c) Transverse CBV map shows decreased CBV (arrows). (d) Transverse MTT map shows slightly elevated MTT (arrows). Changes are consistent with infarction. (e) Follow-up transverse CT image shows large infarct (arrows) in left ACA and MCA territories.

View larger version (110K): [in a new window]   Figure 4d. Acute infarction in a 76-year-old woman who was unresponsive. (a) Initial transverse head CT image shows subtle hypoattenuation (arrows) in left insula, temporal lobe, and frontal lobe. (b) Transverse CBF map shows decreased CBF (arrows) in left ACA and anterior MCA territories, with quantitative values as low as 11 mL/100 g/min. (c) Transverse CBV map shows decreased CBV (arrows). (d) Transverse MTT map shows slightly elevated MTT (arrows). Changes are consistent with infarction. (e) Follow-up transverse CT image shows large infarct (arrows) in left ACA and MCA territories.

View larger version (135K): [in a new window]   Figure 4e. Acute infarction in a 76-year-old woman who was unresponsive. (a) Initial transverse head CT image shows subtle hypoattenuation (arrows) in left insula, temporal lobe, and frontal lobe. (b) Transverse CBF map shows decreased CBF (arrows) in left ACA and anterior MCA territories, with quantitative values as low as 11 mL/100 g/min. (c) Transverse CBV map shows decreased CBV (arrows). (d) Transverse MTT map shows slightly elevated MTT (arrows). Changes are consistent with infarction. (e) Follow-up transverse CT image shows large infarct (arrows) in left ACA and MCA territories.

View larger version (119K): [in a new window]   Figure 5a. Ischemia without infarction in a 47-year-old woman with severe right internal carotid artery stenosis and episodes of left arm numbness. (a) Transverse perfusion CT map shows decreased CBF (arrows) in right ACA and MCA territories, with quantitative values as low as 21 mL/100 g/min. (b) CBV and (c) MTT are both elevated (arrows) on transverse perfusion maps. Changes are consistent with reversible ischemia. CBV is elevated due to cerebral autoregulatory mechanisms, with vasodilatation in response to decreased perfusion. (d) Follow-up transverse CT image obtained 8 months later shows no evidence of cortical infarction.

View larger version (127K): [in a new window]   Figure 5b. Ischemia without infarction in a 47-year-old woman with severe right internal carotid artery stenosis and episodes of left arm numbness. (a) Transverse perfusion CT map shows decreased CBF (arrows) in right ACA and MCA territories, with quantitative values as low as 21 mL/100 g/min. (b) CBV and (c) MTT are both elevated (arrows) on transverse perfusion maps. Changes are consistent with reversible ischemia. CBV is elevated due to cerebral autoregulatory mechanisms, with vasodilatation in response to decreased perfusion. (d) Follow-up transverse CT image obtained 8 months later shows no evidence of cortical infarction.

View larger version (127K): [in a new window]   Figure 5c. Ischemia without infarction in a 47-year-old woman with severe right internal carotid artery stenosis and episodes of left arm numbness. (a) Transverse perfusion CT map shows decreased CBF (arrows) in right ACA and MCA territories, with quantitative values as low as 21 mL/100 g/min. (b) CBV and (c) MTT are both elevated (arrows) on transverse perfusion maps. Changes are consistent with reversible ischemia. CBV is elevated due to cerebral autoregulatory mechanisms, with vasodilatation in response to decreased perfusion. (d) Follow-up transverse CT image obtained 8 months later shows no evidence of cortical infarction.

View larger version (141K): [in a new window]   Figure 5d. Ischemia without infarction in a 47-year-old woman with severe right internal carotid artery stenosis and episodes of left arm numbness. (a) Transverse perfusion CT map shows decreased CBF (arrows) in right ACA and MCA territories, with quantitative values as low as 21 mL/100 g/min. (b) CBV and (c) MTT are both elevated (arrows) on transverse perfusion maps. Changes are consistent with reversible ischemia. CBV is elevated due to cerebral autoregulatory mechanisms, with vasodilatation in response to decreased perfusion. (d) Follow-up transverse CT image obtained 8 months later shows no evidence of cortical infarction.

View larger version (123K): [in a new window]   Figure 6a. Known right common carotid artery occlusion in a 52-year-old man with 3-week history of amaurosis fugax, left-sided weakness and numbness, and left-sided facial droop. (a) Transverse perfusion CT image obtained before acetazolamide challenge shows decreased CBF (arrows) in right ACA and MCA territories. CBV and MTT maps (not shown) revealed elevation of both CBV and MTT. Changes are compatible with reversible ischemia. (b) After acetazolamide injection, there is steal phenomenon in right ACA and MCA territories. Transverse CBF map shows CBF decreased (arrows) from baseline values, indicating hemodynamic stress and tissue at high risk of infarction.

View larger version (119K): [in a new window]   Figure 6b. Known right common carotid artery occlusion in a 52-year-old man with 3-week history of amaurosis fugax, left-sided weakness and numbness, and left-sided facial droop. (a) Transverse perfusion CT image obtained before acetazolamide challenge shows decreased CBF (arrows) in right ACA and MCA territories. CBV and MTT maps (not shown) revealed elevation of both CBV and MTT. Changes are compatible with reversible ischemia. (b) After acetazolamide injection, there is steal phenomenon in right ACA and MCA territories. Transverse CBF map shows CBF decreased (arrows) from baseline values, indicating hemodynamic stress and tissue at high risk of infarction.

View larger version (126K): [in a new window]   Figure 7a. Transverse perfusion CT maps in a 65-year-old man with progressive worsening of left hand and foot numbness and clumsiness. Angiogram (not shown) revealed severe stenosis of precavernous right internal carotid artery. (a) Decreased CBF (arrows) is shown in right ACA and MCA territories before acetazolamide challenge. CBV was normal to elevated and MTT was elevated (not shown). (b) After acetazolamide injection, CBF map reveals decrease (arrows) in CBF values from baseline in right ACA and MCA territories, consistent with steal phenomenon. (c) After angioplasty and stent placement, repeat pre-acetazolamide challenge perfusion CT shows more symmetric CBF between the two hemispheres. CBV and MTT were also more symmetric (not shown). (d) After acetazolamide injection, CBF map now shows augmentation of flow in both hemispheres, with flow increased over that of baseline.

View larger version (121K): [in a new window]   Figure 7b. Transverse perfusion CT maps in a 65-year-old man with progressive worsening of left hand and foot numbness and clumsiness. Angiogram (not shown) revealed severe stenosis of precavernous right internal carotid artery. (a) Decreased CBF (arrows) is shown in right ACA and MCA territories before acetazolamide challenge. CBV was normal to elevated and MTT was elevated (not shown). (b) After acetazolamide injection, CBF map reveals decrease (arrows) in CBF values from baseline in right ACA and MCA territories, consistent with steal phenomenon. (c) After angioplasty and stent placement, repeat pre-acetazolamide challenge perfusion CT shows more symmetric CBF between the two hemispheres. CBV and MTT were also more symmetric (not shown). (d) After acetazolamide injection, CBF map now shows augmentation of flow in both hemispheres, with flow increased over that of baseline.

View larger version (143K): [in a new window]   Figure 7c. Transverse perfusion CT maps in a 65-year-old man with progressive worsening of left hand and foot numbness and clumsiness. Angiogram (not shown) revealed severe stenosis of precavernous right internal carotid artery. (a) Decreased CBF (arrows) is shown in right ACA and MCA territories before acetazolamide challenge. CBV was normal to elevated and MTT was elevated (not shown). (b) After acetazolamide injection, CBF map reveals decrease (arrows) in CBF values from baseline in right ACA and MCA territories, consistent with steal phenomenon. (c) After angioplasty and stent placement, repeat pre-acetazolamide challenge perfusion CT shows more symmetric CBF between the two hemispheres. CBV and MTT were also more symmetric (not shown). (d) After acetazolamide injection, CBF map now shows augmentation of flow in both hemispheres, with flow increased over that of baseline.

View larger version (124K): [in a new window]   Figure 7d. Transverse perfusion CT maps in a 65-year-old man with progressive worsening of left hand and foot numbness and clumsiness. Angiogram (not shown) revealed severe stenosis of precavernous right internal carotid artery. (a) Decreased CBF (arrows) is shown in right ACA and MCA territories before acetazolamide challenge. CBV was normal to elevated and MTT was elevated (not shown). (b) After acetazolamide injection, CBF map reveals decrease (arrows) in CBF values from baseline in right ACA and MCA territories, consistent with steal phenomenon. (c) After angioplasty and stent placement, repeat pre-acetazolamide challenge perfusion CT shows more symmetric CBF between the two hemispheres. CBV and MTT were also more symmetric (not shown). (d) After acetazolamide injection, CBF map now shows augmentation of flow in both hemispheres, with flow increased over that of baseline.

View larger version (124K): [in a new window]   Figure 8a. Images in a 45-year-old man with recent onset of left-sided headache and retro-orbital pain. CT, MR, and angiographic images (not shown) indicated giant left supraclinoid carotid aneurysm. Temporary balloon occlusion was performed to determine if patient could tolerate embolization of the aneurysm and sacrifice of the left internal carotid artery. Perfusion CT was performed as part of the evaluation. (a) Transverse CT image obtained during perfusion CT shows large enhancing aneurysm (arrows) in left frontal region. (b) Transverse perfusion CT map with balloon inflated in left internal carotid artery shows relatively symmetric CBF throughout both hemispheres except in area corresponding to the aneurysm. (c) Transverse CBF map with balloon deflated again demonstrates symmetric CBF except in area of aneurysm (arrows). (d) With balloon inflated after acetazolamide injection, transverse CBF map shows normal augmentation of flow in both hemispheres except in area corresponding to aneurysm. Patient did well after treatment of aneurysm, with no neurologic deficit.

View larger version (144K): [in a new window]   Figure 8b. Images in a 45-year-old man with recent onset of left-sided headache and retro-orbital pain. CT, MR, and angiographic images (not shown) indicated giant left supraclinoid carotid aneurysm. Temporary balloon occlusion was performed to determine if patient could tolerate embolization of the aneurysm and sacrifice of the left internal carotid artery. Perfusion CT was performed as part of the evaluation. (a) Transverse CT image obtained during perfusion CT shows large enhancing aneurysm (arrows) in left frontal region. (b) Transverse perfusion CT map with balloon inflated in left internal carotid artery shows relatively symmetric CBF throughout both hemispheres except in area corresponding to the aneurysm. (c) Transverse CBF map with balloon deflated again demonstrates symmetric CBF except in area of aneurysm (arrows). (d) With balloon inflated after acetazolamide injection, transverse CBF map shows normal augmentation of flow in both hemispheres except in area corresponding to aneurysm. Patient did well after treatment of aneurysm, with no neurologic deficit.

View larger version (130K): [in a new window]   Figure 8c. Images in a 45-year-old man with recent onset of left-sided headache and retro-orbital pain. CT, MR, and angiographic images (not shown) indicated giant left supraclinoid carotid aneurysm. Temporary balloon occlusion was performed to determine if patient could tolerate embolization of the aneurysm and sacrifice of the left internal carotid artery. Perfusion CT was performed as part of the evaluation. (a) Transverse CT image obtained during perfusion CT shows large enhancing aneurysm (arrows) in left frontal region. (b) Transverse perfusion CT map with balloon inflated in left internal carotid artery shows relatively symmetric CBF throughout both hemispheres except in area corresponding to the aneurysm. (c) Transverse CBF map with balloon deflated again demonstrates symmetric CBF except in area of aneurysm (arrows). (d) With balloon inflated after acetazolamide injection, transverse CBF map shows normal augmentation of flow in both hemispheres except in area corresponding to aneurysm. Patient did well after treatment of aneurysm, with no neurologic deficit.

View larger version (139K): [in a new window]   Figure 8d. Images in a 45-year-old man with recent onset of left-sided headache and retro-orbital pain. CT, MR, and angiographic images (not shown) indicated giant left supraclinoid carotid aneurysm. Temporary balloon occlusion was performed to determine if patient could tolerate embolization of the aneurysm and sacrifice of the left internal carotid artery. Perfusion CT was performed as part of the evaluation. (a) Transverse CT image obtained during perfusion CT shows large enhancing aneurysm (arrows) in left frontal region. (b) Transverse perfusion CT map with balloon inflated in left internal carotid artery shows relatively symmetric CBF throughout both hemispheres except in area corresponding to the aneurysm. (c) Transverse CBF map with balloon deflated again demonstrates symmetric CBF except in area of aneurysm (arrows). (d) With balloon inflated after acetazolamide injection, transverse CBF map shows normal augmentation of flow in both hemispheres except in area corresponding to aneurysm. Patient did well after treatment of aneurysm, with no neurologic deficit.

View larger version (139K): [in a new window]   Figure 9a. Images in a 33-year-old man with history of medullary thyroid cancer and metastasis to right cavernous sinus with right cavernous sinus syndrome. Perfusion CT was performed in conjunction with temporary balloon occlusion to determine if patient could tolerate right carotid sacrifice as part of aggressive skull base excision of metastases. (a) Transverse perfusion CT map with balloon inflated before acetazolamide challenge shows globally low CBF in both hemispheres (quantitative values, 13-29 mL/100 g/min) but with asymmetrically lower flow in much of right hemisphere. There was corresponding increased CBV and MTT in the right hemisphere (not shown). (b) Transverse CBF map with balloon deflated shows that CBF is more symmetric but still globally low. (c) Transverse CBF map obtained with balloon inflated after acetazolamide injection shows multiple areas of steal. Because of these findings, patient underwent superficial temporal artery-to-MCA bypass before resection of metastases. (d) Transverse diffusion-weighted MR image (b = 1,000 sec/mm2) obtained after surgery shows graft has become occluded and patient has developed right MCA stroke (arrows).

View larger version (158K): [in a new window]   Figure 9b. Images in a 33-year-old man with history of medullary thyroid cancer and metastasis to right cavernous sinus with right cavernous sinus syndrome. Perfusion CT was performed in conjunction with temporary balloon occlusion to determine if patient could tolerate right carotid sacrifice as part of aggressive skull base excision of metastases. (a) Transverse perfusion CT map with balloon inflated before acetazolamide challenge shows globally low CBF in both hemispheres (quantitative values, 13-29 mL/100 g/min) but with asymmetrically lower flow in much of right hemisphere. There was corresponding increased CBV and MTT in the right hemisphere (not shown). (b) Transverse CBF map with balloon deflated shows that CBF is more symmetric but still globally low. (c) Transverse CBF map obtained with balloon inflated after acetazolamide injection shows multiple areas of steal. Because of these findings, patient underwent superficial temporal artery-to-MCA bypass before resection of metastases. (d) Transverse diffusion-weighted MR image (b = 1,000 sec/mm2) obtained after surgery shows graft has become occluded and patient has developed right MCA stroke (arrows).

View larger version (143K): [in a new window]   Figure 9c. Images in a 33-year-old man with history of medullary thyroid cancer and metastasis to right cavernous sinus with right cavernous sinus syndrome. Perfusion CT was performed in conjunction with temporary balloon occlusion to determine if patient could tolerate right carotid sacrifice as part of aggressive skull base excision of metastases. (a) Transverse perfusion CT map with balloon inflated before acetazolamide challenge shows globally low CBF in both hemispheres (quantitative values, 13-29 mL/100 g/min) but with asymmetrically lower flow in much of right hemisphere. There was corresponding increased CBV and MTT in the right hemisphere (not shown). (b) Transverse CBF map with balloon deflated shows that CBF is more symmetric but still globally low. (c) Transverse CBF map obtained with balloon inflated after acetazolamide injection shows multiple areas of steal. Because of these findings, patient underwent superficial temporal artery-to-MCA bypass before resection of metastases. (d) Transverse diffusion-weighted MR image (b = 1,000 sec/mm2) obtained after surgery shows graft has become occluded and patient has developed right MCA stroke (arrows).

View larger version (95K): [in a new window]   Figure 9d. Images in a 33-year-old man with history of medullary thyroid cancer and metastasis to right cavernous sinus with right cavernous sinus syndrome. Perfusion CT was performed in conjunction with temporary balloon occlusion to determine if patient could tolerate right carotid sacrifice as part of aggressive skull base excision of metastases. (a) Transverse perfusion CT map with balloon inflated before acetazolamide challenge shows globally low CBF in both hemispheres (quantitative values, 13-29 mL/100 g/min) but with asymmetrically lower flow in much of right hemisphere. There was corresponding increased CBV and MTT in the right hemisphere (not shown). (b) Transverse CBF map with balloon deflated shows that CBF is more symmetric but still globally low. (c) Transverse CBF map obtained with balloon inflated after acetazolamide injection shows multiple areas of steal. Because of these findings, patient underwent superficial temporal artery-to-MCA bypass before resection of metastases. (d) Transverse diffusion-weighted MR image (b = 1,000 sec/mm2) obtained after surgery shows graft has become occluded and patient has developed right MCA stroke (arrows).

View larger version (130K): [in a new window]   Figure 10a. Images in a 56-year-old woman with left hemiparesis 5 days after SAH and 1 day after clipping of posterior communicating artery aneurysm. (a) Transverse perfusion CT image reveals decreased CBF in bilateral ACA territories (arrows), with quantitative values of 7 and 17 mL/100 g/min on the right and left, respectively. (b, c) There is corresponding decrease in (b) CBV (arrows) and slight increase in (c) MTT (arrows) on transverse perfusion maps, findings that are of concern for infarction. (d) Subsequent oblique view from right internal carotid angiogram shows severe spasm involving ACAs (arrows). (e) Despite angioplasty, follow-up transverse diffusion-weighted MR image (b = 1,000 sec/mm2) demonstrates restricted diffusion in ACA territories (arrows) corresponding to changes on perfusion CT images.

View larger version (131K): [in a new window]   Figure 10b. Images in a 56-year-old woman with left hemiparesis 5 days after SAH and 1 day after clipping of posterior communicating artery aneurysm. (a) Transverse perfusion CT image reveals decreased CBF in bilateral ACA territories (arrows), with quantitative values of 7 and 17 mL/100 g/min on the right and left, respectively. (b, c) There is corresponding decrease in (b) CBV (arrows) and slight increase in (c) MTT (arrows) on transverse perfusion maps, findings that are of concern for infarction. (d) Subsequent oblique view from right internal carotid angiogram shows severe spasm involving ACAs (arrows). (e) Despite angioplasty, follow-up transverse diffusion-weighted MR image (b = 1,000 sec/mm2) demonstrates restricted diffusion in ACA territories (arrows) corresponding to changes on perfusion CT images.

View larger version (136K): [in a new window]   Figure 10c. Images in a 56-year-old woman with left hemiparesis 5 days after SAH and 1 day after clipping of posterior communicating artery aneurysm. (a) Transverse perfusion CT image reveals decreased CBF in bilateral ACA territories (arrows), with quantitative values of 7 and 17 mL/100 g/min on the right and left, respectively. (b, c) There is corresponding decrease in (b) CBV (arrows) and slight increase in (c) MTT (arrows) on transverse perfusion maps, findings that are of concern for infarction. (d) Subsequent oblique view from right internal carotid angiogram shows severe spasm involving ACAs (arrows). (e) Despite angioplasty, follow-up transverse diffusion-weighted MR image (b = 1,000 sec/mm2) demonstrates restricted diffusion in ACA territories (arrows) corresponding to changes on perfusion CT images.

View larger version (163K): [in a new window]   Figure 10d. Images in a 56-year-old woman with left hemiparesis 5 days after SAH and 1 day after clipping of posterior communicating artery aneurysm. (a) Transverse perfusion CT image reveals decreased CBF in bilateral ACA territories (arrows), with quantitative values of 7 and 17 mL/100 g/min on the right and left, respectively. (b, c) There is corresponding decrease in (b) CBV (arrows) and slight increase in (c) MTT (arrows) on transverse perfusion maps, findings that are of concern for infarction. (d) Subsequent oblique view from right internal carotid angiogram shows severe spasm involving ACAs (arrows). (e) Despite angioplasty, follow-up transverse diffusion-weighted MR image (b = 1,000 sec/mm2) demonstrates restricted diffusion in ACA territories (arrows) corresponding to changes on perfusion CT images.

View larger version (132K): [in a new window]   Figure 10e. Images in a 56-year-old woman with left hemiparesis 5 days after SAH and 1 day after clipping of posterior communicating artery aneurysm. (a) Transverse perfusion CT image reveals decreased CBF in bilateral ACA territories (arrows), with quantitative values of 7 and 17 mL/100 g/min on the right and left, respectively. (b, c) There is corresponding decrease in (b) CBV (arrows) and slight increase in (c) MTT (arrows) on transverse perfusion maps, findings that are of concern for infarction. (d) Subsequent oblique view from right internal carotid angiogram shows severe spasm involving ACAs (arrows). (e) Despite angioplasty, follow-up transverse diffusion-weighted MR image (b = 1,000 sec/mm2) demonstrates restricted diffusion in ACA territories (arrows) corresponding to changes on perfusion CT images.

View larger version (110K): [in a new window]   Figure 11a. Aggressive tumor involving tongue base on the left side in a 59-year-old man. (a) Transverse CT image from perfusion scan. ROIs are placed in the following structures: 1 = carotid artery, 2 = jugular vein, 3 = tongue base cancer, 4 = normal contralateral genioglossus/geniohyoid complex, 5 = ipsilateral genioglossus/geniohyoid complex, 6 = sternocleidomastoid muscle, 7 = paraspinal muscle. (b) Transverse PS map shows increased permeability within tumor (arrows), compared with PS of surrounding tissue. (c) Transverse blood volume map shows increased volume within tumor (arrows), compared with that of adjacent tissue. (d) Transverse blood flow map shows increased flow within tumor (arrows), compared with that of surrounding tissue. (e) Transverse MTT map shows decreased MTT (arrows), compared with that of adjacent normal structures.

View larger version (105K): [in a new window]   Figure 11b. Aggressive tumor involving tongue base on the left side in a 59-year-old man. (a) Transverse CT image from perfusion scan. ROIs are placed in the following structures: 1 = carotid artery, 2 = jugular vein, 3 = tongue base cancer, 4 = normal contralateral genioglossus/geniohyoid complex, 5 = ipsilateral genioglossus/geniohyoid complex, 6 = sternocleidomastoid muscle, 7 = paraspinal muscle. (b) Transverse PS map shows increased permeability within tumor (arrows), compared with PS of surrounding tissue. (c) Transverse blood volume map shows increased volume within tumor (arrows), compared with that of adjacent tissue. (d) Transverse blood flow map shows increased flow within tumor (arrows), compared with that of surrounding tissue. (e) Transverse MTT map shows decreased MTT (arrows), compared with that of adjacent normal structures.

View larger version (98K): [in a new window]   Figure 11c. Aggressive tumor involving tongue base on the left side in a 59-year-old man. (a) Transverse CT image from perfusion scan. ROIs are placed in the following structures: 1 = carotid artery, 2 = jugular vein, 3 = tongue base cancer, 4 = normal contralateral genioglossus/geniohyoid complex, 5 = ipsilateral genioglossus/geniohyoid complex, 6 = sternocleidomastoid muscle, 7 = paraspinal muscle. (b) Transverse PS map shows increased permeability within tumor (arrows), compared with PS of surrounding tissue. (c) Transverse blood volume map shows increased volume within tumor (arrows), compared with that of adjacent tissue. (d) Transverse blood flow map shows increased flow within tumor (arrows), compared with that of surrounding tissue. (e) Transverse MTT map shows decreased MTT (arrows), compared with that of adjacent normal structures.

View larger version (118K): [in a new window]   Figure 11d. Aggressive tumor involving tongue base on the left side in a 59-year-old man. (a) Transverse CT image from perfusion scan. ROIs are placed in the following structures: 1 = carotid artery, 2 = jugular vein, 3 = tongue base cancer, 4 = normal contralateral genioglossus/geniohyoid complex, 5 = ipsilateral genioglossus/geniohyoid complex, 6 = sternocleidomastoid muscle, 7 = paraspinal muscle. (b) Transverse PS map shows increased permeability within tumor (arrows), compared with PS of surrounding tissue. (c) Transverse blood volume map shows increased volume within tumor (arrows), compared with that of adjacent tissue. (d) Transverse blood flow map shows increased flow within tumor (arrows), compared with that of surrounding tissue. (e) Transverse MTT map shows decreased MTT (arrows), compared with that of adjacent normal structures.

View larger version (99K): [in a new window]   Figure 11e. Aggressive tumor involving tongue base on the left side in a 59-year-old man. (a) Transverse CT image from perfusion scan. ROIs are placed in the following structures: 1 = carotid artery, 2 = jugular vein, 3 = tongue base cancer, 4 = normal contralateral genioglossus/geniohyoid complex, 5 = ipsilateral genioglossus/geniohyoid complex, 6 = sternocleidomastoid muscle, 7 = paraspinal muscle. (b) Transverse PS map shows increased permeability within tumor (arrows), compared with PS of surrounding tissue. (c) Transverse blood volume map shows increased volume within tumor (arrows), compared with that of adjacent tissue. (d) Transverse blood flow map shows increased flow within tumor (arrows), compared with that of surrounding tissue. (e) Transverse MTT map shows decreased MTT (arrows), compared with that of adjacent normal structures.

View larger version (139K): [in a new window]   Figure 12a. (a-c) Because fewer major vessel branches (from a to c) are included in the ROI on transverse CBF maps, CBF values decrease.

View larger version (139K): [in a new window]   Figure 12b. (a-c) Because fewer major vessel branches (from a to c) are included in the ROI on transverse CBF maps, CBF values decrease.

View larger version (139K): [in a new window]   Figure 12c. (a-c) Because fewer major vessel branches (from a to c) are included in the ROI on transverse CBF maps, CBF values decrease.

View larger version (140K): [in a new window]   Figure 13a. Depending on the choice of input artery, (a) ACA, (b) right MCA, or (c) left MCA, the quantitative values for CBF vary, as seen on transverse CBF maps.

View larger version (141K): [in a new window]   Figure 13b. Depending on the choice of input artery, (a) ACA, (b) right MCA, or (c) left MCA, the quantitative values for CBF vary, as seen on transverse CBF maps.

View larger version (143K): [in a new window]   Figure 13c. Depending on the choice of input artery, (a) ACA, (b) right MCA, or (c) left MCA, the quantitative values for CBF vary, as seen on transverse CBF maps.

View larger version (113K): [in a new window]   Figure 14a. Images in a 72-year-old man who became confused and developed left-sided ataxia during hepatic angiography. Suspicion of a posterior fossa pathologic condition lead to perfusion CT performed through the level of the cerebellum. (a-c) Transverse perfusion CT maps show (a) decreased CBF (arrows), (b) decreased CBV (arrows), and (c) increased MTT (arrows) in medial left cerebellum. (d) Transverse diffusion-weighted MR image (b = 1,000 sec/mm2) shows corresponding area of restricted diffusion (arrows).

View larger version (125K): [in a new window]   Figure 14b. Images in a 72-year-old man who became confused and developed left-sided ataxia during hepatic angiography. Suspicion of a posterior fossa pathologic condition lead to perfusion CT performed through the level of the cerebellum. (a-c) Transverse perfusion CT maps show (a) decreased CBF (arrows), (b) decreased CBV (arrows), and (c) increased MTT (arrows) in medial left cerebellum. (d) Transverse diffusion-weighted MR image (b = 1,000 sec/mm2) shows corresponding area of restricted diffusion (arrows).

View larger version (113K): [in a new window]   Figure 14c. Images in a 72-year-old man who became confused and developed left-sided ataxia during hepatic angiography. Suspicion of a posterior fossa pathologic condition lead to perfusion CT performed through the level of the cerebellum. (a-c) Transverse perfusion CT maps show (a) decreased CBF (arrows), (b) decreased CBV (arrows), and (c) increased MTT (arrows) in medial left cerebellum. (d) Transverse diffusion-weighted MR image (b = 1,000 sec/mm2) shows corresponding area of restricted diffusion (arrows).

View larger version (115K): [in a new window]   Figure 14d. Images in a 72-year-old man who became confused and developed left-sided ataxia during hepatic angiography. Suspicion of a posterior fossa pathologic condition lead to perfusion CT performed through the level of the cerebellum. (a-c) Transverse perfusion CT maps show (a) decreased CBF (arrows), (b) decreased CBV (arrows), and (c) increased MTT (arrows) in medial left cerebellum. (d) Transverse diffusion-weighted MR image (b = 1,000 sec/mm2) shows corresponding area of restricted diffusion (arrows).