Concordance of regional hypoperfusion by pCASL MRI and <sup>15</sup>O-water PET in frontotemporal dementia: Is pCASL an efficacious alternative?

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Highlights

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ASL is an alternative to ¹⁵O-water for identifying hypoperfusion in FTD patients.
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ROI-based perfusion by ASL and ¹⁵O-water were strongly correlated (R > 0.75).
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Hypoperfusion patterns identified by ¹⁵O-water and ASL were in good agreement.
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Careful selection of the reference region is required to avoid erroneous results.

Abstract

Background

Clinical diagnosis of frontotemporal dementia (FTD) remains a challenge due to the overlap of symptoms among FTD subtypes and with other psychiatric disorders. Perfusion imaging by arterial spin labeling (ASL) is a promising non-invasive alternative to established PET techniques; however, its sensitivity to imaging parameters can hinder its ability to detect perfusion abnormalities.

Purpose

This study evaluated the similarity of regional hypoperfusion patterns detected by ASL relative to the gold standard for imaging perfusion, PET with radiolabeled water ( ¹⁵O-water).

Methods and materials

Perfusion by single-delay pseudo continuous ASL (SD-pCASL), free-lunch Hadamard encoded pCASL (FL_TE-pCASL), and ¹⁵O-water data were acquired on a hybrid PET/MR scanner in 13 controls and 9 FTD patients. Cerebral blood flow (CBF) by ¹⁵O-water was quantified by a non-invasive approach (PMRFlow). Regional hypoperfusion was determined by comparing individual patients to the control group. This was performed using absolute (aCBF) and CBF normalized to whole-brain perfusion (rCBF). Agreement was assessed based on the fraction of overlapping voxels. Sensitivity and specificity of pCASL was estimated using hypoperfused regions of interest identified by ¹⁵O-water.

Results

Region of interest (ROI) based perfusion measured by ¹⁵O-water strongly correlated with SD-pCASL (R = 0.85 ± 0.1) and FL_TE-pCASL (R = 0.81 ± 0.14). Good agreement in terms of regional hypoperfusion patterns was found between ¹⁵O-water and SD-pCASL (sensitivity = 70%, specificity = 78%) and between ¹⁵O-water and FL_TE-pCASL (sensitivity = 71%, specificity = 73%). However, SD-pCASL showed greater overlap (43.4 ± 21.3%) with ¹⁵O-water than FL_TE-pCASL (29.9 ± 21.3%). Although aCBF and rCBF showed no significant differences regarding spatial overlap and metrics of agreement with ¹⁵O-water, rCBF showed considerable variability across subtypes, indicating that care must be taken when selecting a reference region.

Conclusions

This study demonstrates the potential of pCASL for assessing regional hypoperfusion related to FTD and supports its use as a cost-effective alternative to PET.

Related collections

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Author and article information

Contributors

Tracy Ssali

Journal

Journal ID (nlm-ta): Neuroimage Clin

Journal ID (iso-abbrev): Neuroimage Clin

Title: NeuroImage : Clinical

Publisher: Elsevier

ISSN (Electronic): 2213-1582

Publication date PMC-release: 31 January 2022

Publication date Collection: 2022

Publication date (Electronic): 31 January 2022

Volume: 33

Electronic Location Identifier: 102950

Affiliations

[a ]Lawson Health Research Institute, London, Canada

[b ]Department of Medical Biophysics, Western University, London, Canada

[c ]St. Joseph’s Health Care, London, Canada

[d ]Fraunhofer Institute for Medical Image Computing MEVIS, Bremen, Germany

[e ]University Bremen, Bremen, Germany

[f ]Mediri GmbH, Heidelberg, Germany

[g ]Department of Clinical Neurological Sciences, Western University, London, Canada

Author notes

[* ]Corresponding author at: Lawson Health Research Institute, 268 Grosvenor St, London, Ontario N6A4V2, Canada. tssali@ 123456uwo.ca

Article

Publisher Item ID: S2213-1582(22)00015-8 Publisher ID: 102950

DOI: 10.1016/j.nicl.2022.102950

PMC ID: 8829802

PubMed ID: 35134705

SO-VID: c47ec6a3-03fc-4e0d-a615-39415a944070

License:

This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

History

Date received : 24 September 2021

Date revision received : 21 January 2022

Date accepted : 25 January 2022

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