Ultra-high contrast MRI of the brain and spinal cord using directly acquired and synthetic BipoLAr Inversion Recovery (BLAIR) images

Sep 30, 2026

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Ultra-high contrast (UHC) magnetic resonance imaging (MRI) detects abnormalities with high contrast even when conventional state-of-the-art MR sequences show little or none. UHC is obtained without increasing static or gradient magnetic fields, by exploiting tissue properties such as T1 and T2 multiple times within the same sequence, including directly acquired divided subtracted inversion recovery (dSIR) T1-BipoLAr Inversion Recovery (BLAIR). Synthetic bipolar-filter approaches applied to tissue-property maps can also generate high contrast with high spatial resolution. Illustrative cases include mild traumatic brain injury, multiple sclerosis, methamphetamine substance use disorder, Parkinson’s disease, and tumour-associated white-matter changes, revealing widespread abnormalities and characteristic BLAIR signs such as whiteout, grayout, bilaminar cortex, and bubble signs. dSIR/BLAIR contrast derives from small T1 changes and other tissue properties, complementing conventional clinical sequences that rely on larger T1/T2 variations. Comparisons are made against single or combined inversion recovery sequences, and four BLAIR sequence groups are described as easy to implement on most MR systems.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages29

Reading Time1 h 13 min

AccessFree to download

Introduction

Synergistic contrast mechanisms for UHC MRI

dSIR and BLAIR sequence concept

Retrospective synthetic filtering on tissue-property maps

Review Article Ultra-high contrast MRI of the brain and spinal cord using directly acquired and synthetic BipoLAr Inversion Recovery (BLAIR) images Daniel M. Cornfeld1,2, Paul Condron1,2, Mark Bydder1, Tracy R. Melzer3,4,5, Emanuele Pravata6,7, John D. Port8, Samantha J. Holdsworth1,2, Graeme M. Bydder1,9 1Matai Medical Research Institute, Tairāwhiti Gisborne, New Zealand; 2Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences & Centre for Brain Research, University of Auckland, Auckland, New Zealand; 3Te Kura Mahi ā-Hirikapo, School of Psychology, Speech and Hearing, University of Canterbury, Christchurch, New Zealand; 4New Zealand Brain Research Institute, Christchurch, New Zealand; 5Pacific Radiology Canterbury, Christchurch, New Zealand; 6Department of Neuroscience, Imaging and Clinical Sciences, Università G. d’Annunzio, Chieti, Italy; 7Neurocenter of Southern Switzerland, EOC, Lugano, Switzerland; 8Department of Radiology, Mayo Clinic, Rochester, MN, USA; 9Department of Radiology, University of California San Diego, San Diego, CA, USA Contributions: (I) Conception and design: DM Cornfeld, P Condron, M Bydder, TR Melzer, E Pravata, JD Port, GM Bydder; (II) Administrative support: SJ Holdsworth; (III) Provision of study materials or patients: P Condron, M Bydder, TR Melzer; (IV) Collection and assembly of data: DM Cornfeld, P Condron, E Pravata, JD Port; (V) Data analysis and interpretation: DM Cornfeld, P Condron, M Bydder, TR Melzer, GM Bydder; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors. Correspondence to: Graeme M. Bydder, MB ChB. Matai Medical Research Institute, Tairāwhiti Gisborne, New Zealand; Department of Radiology, University of California San Diego, 200 W Arbor Dr, San Diego, CA 92037, USA. Email: [gbydder@health.ucsd.edu](gbydder@health.ucsd.edu). Abstract: Ultra-high contrast (UHC) magnetic resonance imaging (MRI) is a term used to describe magnetic resonance (MR) imaging that shows abnormalities with high contrast when little or no abnormality is seen on common conventional state-of-the-art MR images. It is achieved without the use of increased static or gradient magnetic fields. UHC can be accomplished by using tissue properties such as T1 and T2 twice or more in the same sequence. This synergistically contributes to overall contrast as with directly acquired divided subtracted inversion recovery (dSIR) T1-BipoLAr Inversion Recovery (BLAIR) sequences. These sequences can also provide high contrast and high spatial resolution signal boundaries. UHC MRI can also be achieved by applying synthetic bipolar filters to high quality tissue property maps. Illustrative cases of mild traumatic brain injury (mTBI), multiple sclerosis (MS), methamphetamine substance use disorder, Parkinson’s disease and white matter changes associated with a cerebral tumour are shown. Patients showed widespread abnormalities with directly acquired and synthetic dSIR and other BLAIR images in areas where little or no abnormality was seen on conventional T2-w spin echo and/or T2-FLAIR images. New signs seen on BLAIR images include the whiteout sign and grayout signs as well as the bilaminar cortex and bubble signs. dSIR and other BLAIR sequences create high contrast from small changes in T1 as well as other tissue properties, and are complementary to conventional clinical sequences which create high contrast from larger changes in T1 and/or T2. Comparison is made with other sequences which use single or combined inversion recovery images. Four groups of BLAIR sequences are described. They utilise sequences that already exist on most MR machines and are easy to implement. Keywords: Ultra-high contrast (UHC); divided subtracted inversion recovery sequence (dSIR sequence); BipoLAr Inversion Recovery sequence (BLAIR sequence); traumatic brain injury (TBI); multiple sclerosis (MS) Submitted Aug 03, 2025. Accepted for publication Nov 24, 2025. Publish

FAQs

What does ultra-high contrast (UHC) MRI aim to achieve compared with conventional MRI?

UHC MRI aims to show abnormalities with high contrast when little or no abnormality is visible on common conventional state-of-the-art MRI sequences.

How can UHC MRI be achieved without increasing static or gradient magnetic fields?

By using tissue properties such as T1 and T2 multiple times in the same sequence to build synergistic contrast, including dSIR and BLAIR approaches, or by applying synthetic bipolar filters to high-quality tissue property maps.

Which clinical conditions and distinctive BLAIR signs are reported in the review’s illustrative cases?

Illustrative cases include mild traumatic brain injury, multiple sclerosis, methamphetamine substance use disorder, Parkinson’s disease, and tumour-associated white-matter changes, with reported signs such as the whiteout sign, grayout signs, bilaminar cortex, and bubble signs.

Sep 30, 2026

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