Dynamic CT perfusion for acute cerebral ischemia: increasing anatomical coverage with the “toggling table” technique

P17 Computed tomography (CT) has experienced a revival for perfusion assessment in acute stroke. However, so far it is limited by its small anatomical coverage. We studied a toggling table approach to (multislice) dynamic perfusion CT for extended coverage in patients with suspected acute MCA ischemia. In 20 patients with suspected acute MCA ischemia, a dynamic CT perfusion scan was performed on a multidetector scanner. To increase anatomical coverage, 2 distinct “toggling” table positions (each consisting of two 1cm slices) were chosen to represent the MCA territory and scanned in an alternating fashion during the bolus injection of 40mL contrast agent. Dynamic images were evaluated on a ROI and pixel-by-pixel basis, estimating peak density change, time to peak (TTP), integral (rCBV), mean transit time (MTT), and flow (rCBF). Acutely acquired CT perfusion data were compared with follow-up CT or MR (perfusion and diffusion) images. With the toggling table approach, temporal resolution is reduced to approximately 5 secs. Four imaging slices at two distinct locations can be obtained, covering the MCA territory. In 15 patients, perfusion CT revealed focal abnormalities in at least one slice, most commonly on MTT maps. In 14 of these 15 patients, the area of perfusion abnormality was a good predictor of the ultimate infarct. A single table location approach would have underestimated or missed the involved tissue in most cases. In 5 of the 20 patients, perfusion maps failed to delineate any abnormality: in 4 cases, MRI confirmed the absence of ischemia, in 1 case, CT failed to reveal a small ischemic injury visible on diffusion MRI. Addition of the dynamic CT perfusion scan adds less than 5 minutes to a CT stroke protocol and can be coupled with CTA studies to image the cervical and cerebral vasculature in acute stroke. The dynamic CT perfusion technique is a practical and useful tool for the emergency assessment of acute stroke patients. By employing the toggling table approach, perfusion information can be obtained over an extended anatomic area and thus reveal the presence and the extent of presumed tissue ischemia.

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Abstract T P20: Correlation Between Whole Brain Ct Perfusion Maps And Non-contrast Ct Alberta Stroke Program Early Ct Score (aspects) In Patients Undergoing Acute Endovascular Stroke Interventions

Stroke ◽

10.1161/str.45.suppl_1.tp20 ◽

2014 ◽

Vol 45 (suppl_1) ◽

Author(s):

Simon Morr ◽

Maxim Mokin ◽

Ashish Sonig ◽

Kenneth Snyder ◽

Adnan Siddiqui ◽

...

Keyword(s):

Acute Stroke ◽

Blood Volume ◽

Cerebral Blood Volume ◽

Ct Perfusion ◽

Pearson Correlation ◽

Volume Data ◽

Post Intervention ◽

Whole Brain ◽

Brain Ct ◽

Time To Peak

Introduction: Tools for evaluating risk of post-intervention risk hemorrhage in the setting of acute stroke include a noncontrast head CT based Alberta Stroke Program Early CT score (ASPECTS) and contrasted CT based perfusion plots. The correlation between these parameters is unknown. Methods: We performed a retrospective analysis of a prospectively collected endovascular stroke database of patients with M1 middle cerebral artery occlusion who underwent endovascular recanalization. We reviewed admission preintervention noncontrast CT for Alberta Stroke Program Early CT score (ASPECTS) and 320-detector row whole brain CT perfusion parameters (Cerebral blood volume and time to peak). Pearson correlation was determined between cerebral blood volume on the side of the stroke and ASPECTS. Results: ASPECTS and CT perfusion map were identified in 45 and 43 patients respectively. Statistically significant correlation was found between ASPECTS and cerebral blood volume data on CT perfusion MAP. (p=0.034, r=-0.28). The correlation coefficient is very weak. No correlation could be found between time to peak and ASPECTS. Conclusion: A statistically significant, but weak correlation exists between ASPECTS and CBV. Further research is needed to assess the physiological meaning of diverse imaging modalities utilized in the acute stroke setting.

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Spatial Distribution of Perfusion Abnormality in Acute MCA Occlusion is Associated with Likelihood of Later Recanalization

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2014.13 ◽

2014 ◽

Vol 34 (5) ◽

pp. 813-819 ◽

Cited By ~ 7

Author(s):

Susanne Siemonsen ◽

Nils Daniel Forkert ◽

Anne Hansen ◽

Andre Kemmling ◽

Götz Thomalla ◽

...

Keyword(s):

Acute Stroke ◽

Cerebral Blood Volume ◽

Mean Transit Time ◽

Three Dimensional ◽

Area Under The Curve ◽

Fibrinolytic Therapy ◽

Data Sets ◽

Infarct Core ◽

Compensatory Mechanisms ◽

Time To Peak

The aim of this study is to investigate whether different spatial perfusion-deficit patterns, which indicate differing compensatory mechanisms, can be recognized and used to predict recanalization success of intravenous fibrinolytic therapy in acute stroke patients. Twenty-seven acute stroke data sets acquired within 6 hours from symptom onset including diffusion- (DWI) and perfusion-weighted magnetic resonance (MR) imaging (PWI) were analyzed and dichotomized regarding recanalization outcome using time-of-flight follow-up data sets. The DWI data sets were used for calculation of apparent diffusion coefficient (ADC) maps and subsequent infarct core segmentation. A patient-individual three-dimensional (3D) shell model was generated based on the segmentation and used for spatial analysis of the ADC as well as cerebral blood volume (CBV), cerebral blood flow, time to peak (TTP), and mean transit time (MTT) parameters derived from PWI. Skewness, kurtosis, area under the curve, and slope were calculated for each parameter curve and used for classification (recanalized/nonrecanalized) using a LogitBoost Alternating Decision Tree (LAD Tree). The LAD tree optimization revealed that only ADC skewness, CBV kurtosis, and MTT kurtosis are required for best possible prediction of recanalization success with a precision of 85%. Our results suggest that the propensity for macrovascular recanalization after intravenous fibrinolytic therapy depends not only on clot properties but also on distal microvascular bed perfusion. The 3D approach for characterization of perfusion parameters seems promising for further research.

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Role of Perfusion CT Differentiating Hemangiomas from Malignant Hepatic Lesions

Journal of Clinical Imaging Science ◽

10.4103/2156-7514.127959 ◽

2014 ◽

Vol 4 ◽

pp. 10 ◽

Cited By ~ 10

Author(s):

Jagjeet Singh ◽

Sanjiv Sharma ◽

Neeti Aggarwal ◽

R G Sood ◽

Shikha Sood ◽

...

Keyword(s):

Predictive Value ◽

Multidetector Ct ◽

Ct Perfusion ◽

Mean Transit Time ◽

Liver Parenchyma ◽

Study Data ◽

Perfusion Ct ◽

Hepatic Malignancy ◽

Hepatic Lesions

Objective: The purpose of the study was to determine the role of computed tomography (CT) perfusion in differentiating hemangiomas from malignant hepatic lesions. Materials and Methods: This study was approved by the institutional review board. All the patients provided informed consent. CT perfusion was performed with 64 multidetector CT (MDCT) scanner on 45 patients including 27 cases of metastasis, 9 cases of hepatocellular carcinoma (HCC), and 9 cases of hemangiomas. A 14 cm span of the liver was covered during the perfusion study. Data was analyzed to calculate blood flow (BF), blood volume (BV), permeability surface area product (PS), mean transit time (MTT), hepatic arterial fraction (HAF), and induced residue fraction time of onset (IRFTO). CT perfusion parameters at the periphery of lesions and background liver parenchyma were compared. Results: Significant changes were observed in the perfusion parameters at the periphery of different lesions. Of all the perfusion parameters BF, HAF, and IRFTO showed most significant changes. In our study we found: BF of more than 400 ml/100 g/min at the periphery of the hemangiomas showed sensitivity of 88.9%, specificity of 83.3%, positive predictive value (PPV) of 57.1%, and negative predictive value (NPV) of 96.7% in differentiating hemangiomas from hepatic malignancy; HAF of more than 60% at the periphery of hemangiomas showed sensitivity of 77.8%, specificity of 86.1%, PPV of 58.3% and NPV of 93.9% in differentiating hemangiomas from hepatic malignancy; IRFTO of more than 3 s at the periphery of hemangiomas showed sensitivity of 77.8%, specificity of 86.1%, PPV of 58.3%, and NPV of 93.9% in differentiating hemangiomas from hepatic malignancy. Conclusion: Perfusion CT is a helpful tool in differentiating hemangiomas from hepatic malignancy by its ability to determine changes in perfusion parameters of the lesions.

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Predictive Value of the Velocity of Collateral Filling in Patients with Acute Ischemic Stroke

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2014.182 ◽

2014 ◽

Vol 35 (2) ◽

pp. 206-212 ◽

Cited By ~ 21

Author(s):

Sebastian E Beyer ◽

Louisa von Baumgarten ◽

Kolja M Thierfelder ◽

Marietta Rottenkolber ◽

Hendrik Janssen ◽

...

Keyword(s):

Cerebral Blood Volume ◽

Ct Perfusion ◽

Mean Transit Time ◽

Intravenous Thrombolysis ◽

Lesion Size ◽

Small Lesion ◽

Time Resolved ◽

Time To Peak ◽

Magnetic Resonance Imaging Mri

The velocity of collateral filling can be assessed in dynamic time-resolved computed tomography (CT) angiographies and may predict initial CT perfusion (CTP) and follow-up lesion size. We included all patients with an M1± internal carotid artery (ICA) occlusion and follow-up imaging from an existing cohort of 1791 consecutive patients who underwent multimodal CT for suspected stroke. The velocity of collateral filling was quantified using the delay of time-to-peak (TTP) enhancement of the M2 segment distal to the occlusion. Cerebral blood volume (CBV) and mean transit time (MTT)-CBV mismatch were assessed in initial CTP. Follow-up lesion size was assessed by magnetic resonance imaging (MRI) or non-enhanced CT (NECT). Multivariate analyses were performed to adjust for extent of collateralization and type of treatment. Our study comprised 116 patients. Multivariate analysis showed a short collateral blood flow delay to be an independent predictor of a small CBV lesion ( P<0.001) and a large relative mismatch ( P<0.001) on initial CTP, of a small follow-up lesion ( P<0.001), and of a small difference between initial CBV and follow-up lesion size ( P=0.024). Other independent predictors of a small lesion on follow-up were a high morphologic collateral grade ( P=0.001), lack of an additional ICA occlusion ( P=0.009), and intravenous thrombolysis ( P=0.022). Fast filling of collaterals predicts initial CTP and follow-up lesion size and is independent of extent of collateralization.

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The influence of decompressive craniectomy for major stroke on early cerebral perfusion

Journal of Neurosurgery ◽

10.3171/2014.12.jns141250 ◽

2015 ◽

Vol 123 (1) ◽

pp. 59-64 ◽

Cited By ~ 5

Author(s):

Philipp Jörg Slotty ◽

Marcel Alexander Kamp ◽

Thomas Beez ◽

Henrieke Beenen ◽

Hans-Jakob Steiger ◽

...

Keyword(s):

Decompressive Craniectomy ◽

Cerebral Perfusion ◽

Cerebral Blood Volume ◽

Mean Transit Time ◽

Residue Function ◽

Perfusion Ct ◽

Local Pressure ◽

Partial Restoration ◽

Time To Peak ◽

Major Stroke

OBJECT Multiple trials have shown improved survival and functional outcome in patients treated with decompressive craniectomy (DC) for brain swelling following major stroke. It has been assumed that decompression induces an improvement in cerebral perfusion. This observational study directly measured cerebral perfusion before and after decompression. METHODS Sixteen patients were prospectively examined with perfusion CT within 6 hours prior to surgery and 12 hours after surgery. Preoperative and postoperative perfusion measurements were compared and correlated. RESULTS Following DC there was a significant increase in cerebral blood flow in all measured territories and additionally an increase in cerebral blood volume in the penumbra (p = 0.03). These changes spread as far as the contralateral hemisphere. No significant changes in mean transit time or Tmax (time-to-peak residue function) were observed. CONCLUSIONS The presurgical perfusion abnormalities likely reflected local pressure-induced hypoperfusion with impaired autoregulation. The improvement in perfusion after decompression implied an increase in perfusion pressure, likely linked to partial restoration of autoregulation. The increase in perfusion that was observed might partially be responsible for improved clinical outcome following decompressive surgery for major stroke. The predictive value of perfusion CT on outcome needs to be evaluated in larger trials.

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Two-Volume Dynamic CT Pulmonary Perfusion: Contrast Timing Optimization

10.21203/rs.3.rs-158655/v1 ◽

2021 ◽

Author(s):

Yixiao Zhao ◽

Logan Hubbard ◽

Shant Malkasian ◽

Pablo Abbona ◽

Sabee Molloi

Keyword(s):

Radiation Dose ◽

Ct Perfusion ◽

Optimal Timing ◽

Pulmonary Perfusion ◽

Dynamic Ct ◽

Perfusion Technique ◽

Low Radiation Dose ◽

Time To Peak ◽

Injection Duration ◽

Perfusion Measurements

Abstract PurposeTo develop and validate an optimal timing protocol for a low-radiation-dose CT pulmonary perfusion technique using only two volume scans.MethodsA total of 24 swine (48.5 ± 14.3 kg) underwent contrast-enhanced dynamic CT. Multiple contrast injections were made under different pulmonary perfusion conditions, resulting in a total of 147 complete pulmonary arterial input functions(AIF). Using the AIFs, an optimal timing protocol for acquisition of two-volume scans was developed for the first-pass CT perfusion technique. Specifically, the first volume scan was obtained at the base of the AIF using bolus-tracking and the second volume scan was obtained at the peak of the AIF using a time-to-peak relation derived by regression analysis. Additionally, a subset of 14 swine with 60 CT acquisitions were used to validate the prospective timing protocol. The prospective perfusion measurements using the two-volume scans, were quantitatively compared to the retrospective perfusion measurements using the entire AIF with t-test, linear regression and Bland-Altman analysis. The CT dose index(CTDI32vol) and size-specific dose estimate(SSDE) of the two-volume perfusion technique were also determined.ResultsThe pulmonary artery time-to-peak (TPA) was related to one-half of the contrast injection duration(TInj/2) by TPA = 1.06 TInj/2+0.090 (r=0.97). Simulated prospective two-volume perfusion measurements (PPRO) in ml/min/g were related to the retrospective measurements (PRETRO) by PPRO= 0.87PRETRO + 0.56 (r=0.88). The CTDI32vol and SSDE of the two-volume CT technique were estimated to be 28.4 and 47.0mGy, respectively.ConclusionThe optimal timing protocol can enable an accurate, low-radiation-dose two-volume dynamic CT perfusion technique.

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Chemical thrombolysis with extended 15-hour window in a patient undergoing perfusion CT scan with Rapid CT protocol: a case report

10.5327/1516-3180.516 ◽

2021 ◽

Author(s):

Hendrick Henrique Fernandes Gramasco ◽

Maria Clara Foloni ◽

Rebeca Aranha Barbosa Sousa ◽

Yasmim Nadime José Frigo ◽

Mateus Felipe dos Santos ◽

...

Keyword(s):

Case Report ◽

Acute Stroke ◽

Cerebral Artery ◽

Ct Perfusion ◽

Reperfusion Therapy ◽

Tertiary Hospital ◽

Perfusion Ct ◽

Left Middle Cerebral Artery ◽

Ct Protocol ◽

The Right

Context: Recently, with the advance of neuroimaging modalities, the windows of reperfusion therapy in patients with acute stroke have been reviewed and extended, especially for mechanical thrombectomy. Case report: 81 year old patient, previously hypertensive and dyslipidemic, fully functional (modified Rankin scale = 0), admitted to the emergency room of a tertiary hospital with global aphasia, right hemiparesis, right homonymous hemianopsia and severe hypoesthesia of the right upper limb, scoring 26 on the NIHSS, with report of having contacted family members for the last time 15 hours before admission. She was treated according to the institution’s acute stroke protocol, and underwent non-contrast brain computed tomography (CT), perfusion CT with Rapid CT protocol and cerebral artery + neck angio-CT, which ruled out bleeding and showed an ASPECTS of 8, an estimated ischemic core volume of 17 mL, and an area with hypoperfusion of 118 mL (perfusional mismatch of 101 mL), besides occlusion of the M1 segment of the left middle cerebral artery. Thus, she was submitted to chemical thrombolysis, with a decrease in NIHSS score to 15 and evolving without complications upon hospitalization. Conclusions: In patients with uncertain ictus, the use of advanced neuroimaging modalities, such as perfusion tomography with Rapid CT protocol, may assist in the indication of reperfusion therapies safely.

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Acute Anterior Circulation Stroke: Recanalization Using Clot Angioplasty

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/s0317167100005011 ◽

2006 ◽

Vol 33 (2) ◽

pp. 217-222 ◽

Cited By ~ 20

Author(s):

Cheemun Lum ◽

Peter K. Stys ◽

Matthew J. Hogan ◽

Thanh B. Nguyen ◽

Ashok Srinivasan ◽

...

Keyword(s):

Acute Stroke ◽

Balloon Angioplasty ◽

Cerebral Blood Volume ◽

Internal Carotid ◽

Ct Perfusion ◽

Mean Transit Time ◽

Anterior Circulation ◽

Perfusion Studies ◽

Intravenous Tissue Plasminogen Activator ◽

Symptomatic Intracranial Hemorrhage

ABSTRACT:Background and Purpose:Different strategies have been employed to recanalize acutely occluded middle cerebral and internal carotid arteries (ICA) in the setting of acute stroke including intravenous and intra-arterial tPA. However, pharmaceutical thrombolysis alone, may not be effective in patients with a large amount of clot volume (complete M1, terminal internal carotid artery). We report our initial experience with endovascular clot disruption using a soft silicone balloon in addition to intravenous or intraarterial thrombolysis with tPA.Methods:This is a retrospective review of nine patients with symptoms of acute stroke from clot in the middle cerebral or internal carotid territories who were treated with intracranial balloon angioplasty. All patients presented with symptoms of acute anterior circulation stroke less than six hours from onset. Patients in whom computed tomography (CT) angiography confirmed the presence of large vessel clot (terminal ICA, M1 or proximal M2) were included in the study. A CT perfusion was performed providing maps of cerebral blood volume, flow and mean transit time. If the patient presented less than three hours from onset then intravenous tissue plasminogen activator (tPA) was also administered. Intra-arterial tPA was delivered into the clot. If the volume of clot was judged to be significant by the treating neurointerventionist, then a limited trial of tPA was administered intraarterially followed by balloon angioplasty of persistant clot. The time from imaging to vessel recanalization was recorded. Clinical outcomes were assessed using the modified Rankin scale and Barthel Index.Results:Diagnostic CT perfusion studies were performed in 7 (78%), all of which showed a significant amount of salvageable tissue as judged by the treating neurointerventionist and neurologist. Recanalization (TIMI 2 or 3) was possible in 8 (89%). There were no cases of symptomatic intracranial hemorrhage and 2 (22%) asymptomatic hemorrhages. The average time from performance of the initial emergency CT to vessel recanalization was 2.1 hours with mean time from symptom onset to vessel recanalization of 4.1 hours. Five (56%) patients had good outcomes, 1 (11%) had mild and 3 (33%) had moderate to severe disability.Conclusion:Clot angioplasty can potentially shorten recanalization times in well-selected patients and can be an effective complimentary procedure in patients with tPA resistant clot. Angioplasty can be performed with a very low complication rate using the technique described and may be associated with good outcomes.

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Abstract TP245: Prediction of Hemorrhagic Transformation in Patients With Acute Ischaemic Stroke and Atrial Fibrillation With Ct Perfusion Aspects Scores

Stroke ◽

10.1161/str.48.suppl_1.tp245 ◽

2017 ◽

Vol 48 (suppl_1) ◽

Author(s):

Qiaoshu Wang ◽

Yanyan Cao ◽

Yongbo Zhao ◽

Louis Caplan

Keyword(s):

Atrial Fibrillation ◽

Ischemic Stroke ◽

Acute Stroke ◽

Acute Ischemic Stroke ◽

Roc Analysis ◽

Cerebral Blood Volume ◽

Ct Perfusion ◽

Mean Transit Time ◽

Operating Characteristics ◽

Middle Cerebral Artery Infarction

Background and Purpose: Hemorrhage transformation (HT) is common in patients with acute cerebral infarction caused by atrial fibrillation. The prediction of HT is crucial after acute stroke, especially for the patients received vessel recanalization therapy. The Alberta Stroke program early CT score (ASPECTS) is used to estimate early ischemic changes within the MCA territory in the acute stroke setting. Several studies indicated that CT perfusion (CTP) and MR diffusion weighted imaging (DWI) ASPECTS scores was useful to quantify the degree of ischemic brain tissue. Hereby we did the study to explore the association of CT perfusion ASPECTS scores with HT in patients with acute ischemic stroke and atrial fibrillation. Methods: This was a single center retrospective study. All patients with middle cerebral artery infarction and atrial fibrillation from September 2008 to September 2013 were included. MR imaging including DWI and gradient echo sequence (GRE), and CTP were required to identify the HT and determine the scores of CTP- ASPECTS. Demographic and clinical characteristics of the HT positive and negative groups were explored. Results: Fifty-four patients were analyzed, among them twenty-four patients (44%) developed HT. According to logistic regression analysis, mean transit time (MTT), cerebral blood volume (CBV) and DWI-ASPECTS scores were associated with HT ( p = 0.035, 0.044, and 0.020 respectively). The following receiver operating characteristics (ROC) analysis revealed area under the curve of MTT, CBV, CBF and DWI were 0.588, 0.737, 0.687, and 0.841 respectively. CBV-ASPECTS score was found to have medium prediction value of HT among all CTP-ASPECTS parameters. ROC analysis also indicated that CBV-ASPECTS score < 7 was the optimal threshold. Conclusions: CTP-ASPECTS was useful to predict the HT of acute ischemic stroke caused by atrial fibrillation and CBV-ASPECTS score < 7 was the preferable parameter.

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Two-volume Dynamic CT Pulmonary Perfusion: Contrast Timing Optimization

10.21203/rs.3.rs-158655/v2 ◽

2021 ◽

Author(s):

Yixiao Zhao ◽

Logan Hubbard ◽

Shant Malkasian ◽

Pablo Abbona ◽

Sabee Molloi

Keyword(s):

Radiation Dose ◽

Ct Perfusion ◽

Optimal Timing ◽

Pulmonary Perfusion ◽

Dynamic Ct ◽

Perfusion Technique ◽

Low Radiation Dose ◽

Time To Peak ◽

Injection Duration ◽

Perfusion Measurements

Abstract Purpose: To develop and validate an optimal timing protocol for a low-radiation-dose CT pulmonary perfusion technique using only two volume scans.Methods: A total of 24 swine (48.5±14.3 kg) underwent contrast-enhanced dynamic CT. Multiple contrast injections were made under different pulmonary perfusion conditions, resulting in a total of 147 complete pulmonary arterial input functions(AIFs). Using all the AIF curves, an optimal contrast timing protocol was developed for a first-pass, two-volume dynamic CT perfusion technique (one at the base and the other at the peak of AIF curve). A subset of 14 swine with 70 CT acquisitions were used to validate the prospective timing protocol. The prospective two-volume perfusion measurements were quantitatively compared to the previously validated retrospective perfusion measurements with t-test, linear regression and Bland-Altman analysis. Results: The pulmonary artery time-to-peak ( Tpa) was related to one-half of the contrast injection duration( Tinj/2) by Tpa = 1.06 Tinj/2 + 0.90 (r=0.97). The prospective two-volume perfusion measurements (PPRO) were related to the retrospective measurements (PRETRO) by PPRO=0.87PRETRO+0.56 (r=0.88). The CT dose index and size-specific dose estimate of the two-volume CT technique were estimated to be 28.4 and 47.0mGy, respectively. Conclusion: The optimal timing protocol can enable an accurate, low-radiation-dose two-volume dynamic CT perfusion technique.

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