Presentation on theme: "Can CT Perfusion Evaluate Cerebral Hemodynamic Change in Chronic Occlusive Cerebrovascular Diseases? - Comparison with Diamox-enhanced SPECT - M. Hirata."— Presentation transcript:
Can CT Perfusion Evaluate Cerebral Hemodynamic Change in Chronic Occlusive Cerebrovascular Diseases? - Comparison with Diamox-enhanced SPECT - M. Hirata MD, Y. Sugawara MD, K. Kikuchi MD, H. Miki MD, T. Mochizuki MD, K. Murase PhD, S. Yamauchi RN
INTRODUCTION Cerebral perfusion parameters such as cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) are important for the determination of medical treatment plan and/or prognostic prediction of patients with cerebrovascular diseases (CVDs) (1, 2). Although the utilities of CT perfusion in acute stroke have been reported by many investigators (3-6), the role of quantitative CT perfusion parameters in patients with chronic occlusive CVD has not been elucidated enough (7). (1, 2)(3-6)(7) Prior studies from our group and others have shown that CBF and cerebral perfusion reserve (CPR) measurements using Diamox enhancement and SPECT are useful to evaluate hemodynamic status in chronic occlusive CVDs (8, 9).(8, 9) In this exhibit, we will present the quantitative results of CT perfusion parameters in chronic occlusive CVDs and compare these with the data of Diamox-SPECT. Finally, we will discuss about the advantages and limitations in each of perfusion imaging modalities.
Learning Objectives: 1.Describe the comparative results for quantitative values of CBF, CBV and MTT measured by CT perfusion in comparison with Diamox-enhanced SPECT. 2.Clarify the utilities and limitations in CT perfusion parameters in management of patients with chronic occlusive cerebrovascular diseases.
BACKGROUND Xe-133 SPECT in patients with chronic CVDs Significantly increased immediately after treatment. Therapeutic effects continue on follow-up Increased little immediately after PTA and stenting. No significant changes on follow-up Cerebral Perfusion Reserve PTA and/or stenting Cerebral Blood Flow We previously reported that cerebral perfusion reserve (CPR) significantly increased, but cerebral blood flow increased little immediately after PTA and /or stenting. Therefore, measurement of CPR is useful for evaluating therapeutic effects and for follow-up after PTA and stenting. Sugawara, et al. (SNM 2000) Hirata, et al. (SNM 2003)
BACKGROUND The MTT values in the territories of severely decreased CPR were significantly higher than those in the territories of moderately decreased or normal CPR Severe CPR impairment can be estimated with MTT (8).(8) MR perfusion in patients with chronic CVDs Perfusion reserve Severely decreasedCPR 0% Moderately decreased0% < CPR 15% NormalCPR > 15 %
CBF CBV MTT CBF CBV MTT REST DIAMOX 42 (27%) Post PTA MR Perfusion 133 Xe-SPECT CT Perfusion BACKGROUND MR Perfusion CBF CBV MTT REST DIAMOX 23 (-13%) 133 Xe-SPECT Pre PTA 26 Decrease of CPR Increase of MTT Improvement of CPR Normalization of MTT An example case: 73/M, PTA for Lt. MCA stenosis
Can CT Perfusion Evaluate Cerebral Hemodynamic Change in Chronic Occlusive Cerebrovascular Diseases? CT perfusion Mean Transit Time (MTT) Cerebral Blood Volume (CBV) Cerebral Blood Flow (CBF) Diamox-enhanced 133 Xe SPECT Cerebral Perfusion Reserve (CPR) ? relation Comparison of CBF, CBV and MTT measured by CT perfusion with CPR measured by Diamox-enhanced SPECT
METHODS CT perfusion protocol –CT Scanner: Light Speed QX/i (GE) or Ultra (GE) –Dynamic Scan: Contrast medium: 300 mgI/ml, total ml 3-4 ml/s with power injector Cine mode (5mm x 4i, 1 sec/rot) 5 sec delay for 60 sec –Data Analysis: Advantage Workstation 4.2 with CT perfusion 3 Xe-133 SPECT protocol –Xe-133 gas (1850 MBq) inhalation (Kanno-Lassen method) –Dynamic SPECT (20 s/scan x 16, Hitachi SPECT 2000H-40) –At rest and after Diamox ® (1g) SUBJECTS –6 male patients with chronic occlusive CVDs (Mean age = 63.3 ± 9.3 years) Rt. MCA stenosis: 2 Lt. MCA stenosis: 2 Rt.ICA and MCA stenosis with Lt. ICA occlusion: 1 Rt.ICA occlusion : 1
METHODS MTT CBV CBF CT perfusion CPR = ×100 (%) CBF(Diamox) - CBF(Rest) CBF(Rest) 133 Xe-SPECT Mean value in MCA territory Mean CPR in MCA territory Regions of interest were placed in the MCA territories. The values of CBF, CBV and MTT measured by CT perfusion were compared with CPR values obtained from Diamox-enhanced 133 Xe-SPECT.
Results -Relation between CPR and CTP parameters- Positive correlation was found between CBF and CPR. Negative correlation was found between CBV and CPR. Negative correlation was found between MTT and CPR. The strongest correlation was found in MTT CPR CBF (mL/100g/min) r = 0.58 CPR CBV (mL/100 g) r = CPR MTT (sec) r = (%) (%) (%) Positive correlation was found between CBF and CPR. Negative correlation was found between CBV and CPR. Negative correlation was found between MTT and CPR. The strongest correlation was found in MTT
Case 1. 57/M, Rt. MCA Occlusion The MTT values in the territories of severely decreased CPR were higher than those in the territories of moderately decreased or normal CPR CBFCBVMTT CT Perfusion CBFCBVMTT r= r= 0.24 r= CPR (mL/100 g)(mL/100g/min)(sec) CPR 25% 40% 23% 38% 44%37% 25% -24% -26% 0% 37% 133 Xe-SPECT CPR
Summary 1 Every CT perfusion parameters correlate with CPR. MTT is the most sensitive to reflect severely decreased CPR in chronic occlusive CVDs.
What is the limitation in CT perfusion in management of patients with chronic occlusive cerebrovascular diseases?
Assessment of the therapeutic effects - Two example cases CASE 1 STA-MCA anastomasis for Rt. ICA occlusion CASE 2 CEA for Rt. ICA Stenosis
CASE.1 66/M, STA-MCA anastomasis for Rt. ICA occlusion REST Pre STA-MCA DIAMOX CBF CBV MTT CT Perfusion 30 (0%) (26%) Xe-SPECT REST Post STA-MCA DIAMOX CBF CBV MTT CT Perfusion (4%) (6%) 133 Xe-SPECT On CT perfusion CBF values were decreased. CBV and MTT values were increased. On 133 Xe-SPECT CBF and CPR were decreased in Rt. MCA territory. On 133 Xe-SPECT and CT perfusion No remarkable change was found.
Normal Decrease of Perfusion Reserve Misery Perfusion Infarction CBF CBV MTT OEF CMRO 2 CASE Xe- SPECT CT Perfusion CBF CPRCBV MTT On 133 Xe-SPECT, both CBF and CPR were decreased in Rt. MCA territory. This area could be categorized to "misery perfusion" in which CBF is reduced and the oxygen extraction fraction (OEF) is increased to maintain the cerebral metabolic rate of oxygen (CMRO 2 ) (10). (10) CT perfusion represented decrease of CBF and increase of CBV and MTT.
On 133 Xe-SPECT CPR increased after treatment. No remarkable change was found on CBF. On CT perfusion No remarkable change was found on CBF, CBV and MTT. On 133 Xe-SPECT CPR was decreased in the Rt. MCA territory. CBF was not decreased. CASE.2 51 (18%) 43 (2%) 57 (29%) 61 (37%) CBF CBV MTT CBF CBV MTT Pre CEAPost CEA REST DIAMOX /M, CEA for Rt. ICA Stenosis CT Perfusion 133 Xe-SPECT On CT perfusion CBF, CBV and MTT were normal. 4.6
Normal Decrease of Perfusion Reserve Misery Perfusion Infarction CBF CBV MTT OEF CMRO 2 CASE Xe- SPECT CT Perfusion CBF CPR CBV MTT On 133 Xe-SPECT, only CPR was decreased in Rt. MCA territory. In this case, CBF, OEF and CMRO 2 were maintained by autoregulatory vasodilatation (i.e. increase of CBV) (10). (10) However, all CT perfusion parameters were normal. This suggest that CT perfusion potentially has limitation in the detection of mild hemodynamic changes.
Summary 2 Severe ischemic change is detectable by CT perfusion CT perfusion potentially has limitation in the detection of mild ischemic changes.
Conclusion MTT is the most sensitive to reflect severely decreased CPR in chronic occlusive CVDs. CT perfusion potentially has limitation in the detection of mild ischemic changes.
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