CT Brain Perfusion Protocol to Eliminate the Need for Selecting a Venous Output Function

Riordan, Alan J.; Bennink, Edwin; Viergever, Max A.; Velthuis, Birgitta K.; Dankbaar, Jan Willem; Jong, Hugo W. A. M. de

doi:10.3174/ajnr.a3397

Cited by 10 publications

(10 citation statements)

References 23 publications

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“…These thicker slices may also introduce more partial volume effects[24]. In particular measurements from vessels not perpendicular to the slice plane may suffer from partial volume effects, which will affect the ICA more than the larger venous sinus.…”

Section: Discussionmentioning

confidence: 99%

“…The geometry of the cone beam with a large field of view meant that the data sets were restricted to 6.5 cm axial coverage. The thin 1 mm slice thickness is required to ensure the absence of PVE in the AIF taken from the ICA should it cross the slice plane at an oblique angle [24], [25]. Forty millilitres of nonionic contrast agent (Iopromide, Ultravist, 300 mg iodine/ml; Schering, Berlin, Germany) was injected into the cubital vein (18-gauge needle) at a rate of 6 ml/s followed by a forty millilitres saline flush at a rate of 6 ml/s by using a dual power injector (Stellant Dual CT injector; Medrad Europe, Beek, the Netherlands).…”

Section: Methodsmentioning

confidence: 99%

“…The ICA and SSS were selected to be approximately perpendicular to the slice plane[19], [24]. Circular ROIs were manually drawn on the blood vessel locations on the maximum intensity projection of the patient data.…”

Section: Methodsmentioning

confidence: 99%

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Comparison of Partial Volume Effects in Arterial and Venous Contrast Curves in CT Brain Perfusion Imaging

et al. 2014

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PurposeIn brain CT perfusion (CTP), the arterial contrast bolus is scaled to have the same area under the curve (AUC) as the venous outflow to correct for partial volume effects (PVE). This scaling is based on the assumption that large veins are unaffected by PVE. Measurement of the internal carotid artery (ICA), usually unaffected by PVE due to its large diameter, may avoid the need for partial volume correction. The aims of this work are to examine i) the assumptions behind PVE correction and ii) the potential of selecting the ICA obviating correction for PVE.MethodsThe AUC of the ICA and sagittal sinus were measured in CTP datasets from 52 patients. The AUCs were determined by i) using commercial CTP software based on a Gaussian curve-fitting to the time attenuation curve, and ii) by simple integration of the time attenuation curve over a time interval. In addition, frames acquired up to 3 minutes after first bolus passage were used to examine the ratio of arterial and venous enhancement. The impact of selecting the ICA without PVE correction was illustrated by reporting cerebral blood volume (CBV) measurements.ResultsIn 49 of 52 patients, the AUC of the ICA was significantly larger than that of the sagittal sinus (p = 0.017). Measured after the first pass bolus, contrast enhancement remained 50% higher in the ICA just after the first pass bolus, and 30% higher 3 minutes later. CBV measurements were significantly lowered when the ICA was used without PVE correction.ConclusionsContradicting the assumptions underlying PVE correction, contrast in the ICA was significantly higher than in the sagittal sinus, even 3 minutes after the first pass of the contrast bolus. PVE correction might lead to overestimation of CBV if the CBV is calculated using the AUC of the time attenuation curves.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Comparison of Partial Volume Effects in Arterial and Venous Contrast Curves in CT Brain Perfusion Imaging

et al. 2014

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“…Partial volume effect was considered sufficiently small for the AIF measured on MCA using thin-slice CT data. 24 As with the hematocrit correction mentioned above, the partial volume effect correction in AIF did not directly affect the results because the parameter measured was lesion-to-normal CBF ratio, not absolute CBF.…”

Section: Deconvolution Analysismentioning

confidence: 94%

Reliability of CT Perfusion-Derived CBF in Relation to Hemodynamic Compromise in Patients with Cerebrovascular Steno-Occlusive Disease: A Comparative Study with ¹⁵O PET

Ibaraki

Ohmura

Matsubara

et al. 2015

J Cereb Blood Flow Metab

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In the bolus tracking technique with computed tomography (CT) or magnetic resonance imaging, cerebral blood flow (CBF) is computed from deconvolution analysis, but its accuracy is unclear. To evaluate the reliability of CT perfusion (CTP)-derived CBF, we examined 27 patients with symptomatic or asymptomatic unilateral cerebrovascular steno-occlusive disease. Results from three deconvolution algorithms, standard singular value decomposition (sSVD), delay-corrected SVD (dSVD), and block-circulant SVD (cSVD), were compared with (15)O positron emission tomography (PET) as a reference standard. To investigate CBF errors associated with the deconvolution analysis, differences in lesion-to-normal CBF ratios between PET and CTP were correlated with prolongation of arterial-tissue delay (ATD) and mean transit time (MTT) in the lesion hemisphere. Computed tomography perfusion results strongly depended on the deconvolution algorithms used. Standard singular value decomposition showed ATD-dependent underestimation of CBF ratio, whereas cSVD showed overestimation of the CBF ratio when MTT was severely prolonged in the lesions. The computer simulations reproduced the trend observed in patients. Deconvolution by dSVD can provide lesion-to-normal CBF ratios less dependent on ATD and MTT, but requires accurate ATD maps in advance. A practical and accurate method for CTP is required to assess CBF in patients with MTT-prolonged regions.

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“…First, a slice thickness of 1.8 mm and smaller permits the selection of a partial volume free arterial input function (AIF) in the middle cerebral artery, thus avoiding the necessity for selecting a venous output function (VOF) to correct for partial volume effects (PVE) [ 15 ]. It is hypothesized that a significant proportion of the variability found between observers and between analysis platforms in absolute quantification of perfusion values [ 6 , 16 , 17 ] may be due to the selection of partial volume affected arteries and veins.…”

Section: Introductionmentioning

confidence: 99%

Influence of Thin Slice Reconstruction on CT Brain Perfusion Analysis

et al. 2015

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ObjectivesAlthough CT scanners generally allow dynamic acquisition of thin slices (1 mm), thick slice (≥5 mm) reconstruction is commonly used for stroke imaging to reduce data, processing time, and noise level. Thin slice CT perfusion (CTP) reconstruction may suffer less from partial volume effects, and thus yield more accurate quantitative results with increased resolution. Before thin slice protocols are to be introduced clinically, it needs to be ensured that this does not affect overall CTP constancy. We studied the influence of thin slice reconstruction on average perfusion values by comparing it with standard thick slice reconstruction.Materials and MethodsFrom 50 patient studies, absolute and relative hemisphere averaged estimates of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and permeability-surface area product (PS) were analyzed using 0.8, 2.4, 4.8, and 9.6 mm slice reconstructions. Specifically, the influence of Gaussian and bilateral filtering, the arterial input function (AIF), and motion correction on the perfusion values was investigated.ResultsBilateral filtering gave noise levels comparable to isotropic Gaussian filtering, with less partial volume effects. Absolute CBF, CBV and PS were 22%, 14% and 46% lower with 0.8 mm than with 4.8 mm slices. If the AIF and motion correction were based on thin slices prior to reconstruction of thicker slices, these differences reduced to 3%, 4% and 3%. The effect of slice thickness on relative values was very small.ConclusionsThis study shows that thin slice reconstruction for CTP with unaltered acquisition protocol gives relative perfusion values without clinically relevant bias. It does however affect absolute perfusion values, of which CBF and CBV are most sensitive. Partial volume effects in large arteries and veins lead to overestimation of these values. The effects of reconstruction slice thickness should be taken into account when absolute perfusion values are used for clinical decision making.

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CT Brain Perfusion Protocol to Eliminate the Need for Selecting a Venous Output Function

Cited by 10 publications

References 23 publications

Comparison of Partial Volume Effects in Arterial and Venous Contrast Curves in CT Brain Perfusion Imaging

Comparison of Partial Volume Effects in Arterial and Venous Contrast Curves in CT Brain Perfusion Imaging

Reliability of CT Perfusion-Derived CBF in Relation to Hemodynamic Compromise in Patients with Cerebrovascular Steno-Occlusive Disease: A Comparative Study with ¹⁵O PET

Influence of Thin Slice Reconstruction on CT Brain Perfusion Analysis

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CT Brain Perfusion Protocol to Eliminate the Need for Selecting a Venous Output Function

Cited by 10 publications

References 23 publications

Comparison of Partial Volume Effects in Arterial and Venous Contrast Curves in CT Brain Perfusion Imaging

Comparison of Partial Volume Effects in Arterial and Venous Contrast Curves in CT Brain Perfusion Imaging

Reliability of CT Perfusion-Derived CBF in Relation to Hemodynamic Compromise in Patients with Cerebrovascular Steno-Occlusive Disease: A Comparative Study with 15O PET

Influence of Thin Slice Reconstruction on CT Brain Perfusion Analysis

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Reliability of CT Perfusion-Derived CBF in Relation to Hemodynamic Compromise in Patients with Cerebrovascular Steno-Occlusive Disease: A Comparative Study with ¹⁵O PET