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|Year : 2021 | Volume
| Issue : 2 | Page : 397-398
Double Inversion Recovery: Another Feather in MRI Cap
Consultant Radiologist, Dr Gulati Imaging Institute, Delhi, India
|Date of Submission||31-Mar-2021|
|Date of Decision||31-Mar-2021|
|Date of Acceptance||31-Mar-2021|
|Date of Web Publication||24-Apr-2021|
Consultant Radiologist, Dr Gulati Imaging Institute, Delhi
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Gulati P. Double Inversion Recovery: Another Feather in MRI Cap. Neurol India 2021;69:397-8
Inversion recovery sequence of Magnetic Resonance Imaging (MRI) is primarily used to suppress signal from specific tissue or fluid, double inversion recovery (DIR), on the other hand, is a sequence that suppresses both cerebral spinal fluid signal (CSF) and white matter signal by applying two inversion pulses with two different inversion times making it possible to distinguish normal tissue from the abnormal where there is even subtle difference in T1 relaxation time. This improves the sensitivity of MRI in picking up white matter lesions, especially lesions at the grey-white matter junction.
Although not limited to it, major work on DIR has been done in multiple sclerosis (MS). Traditionally MS was considered to be a disease of demyelination in the white matter. However, we know that involvement of cortical grey matter is increasingly becoming more important and there has been an association of cortical lesions with clinical and cognitive impairment in MS making it essential to better assess these lesions., Conventional sequences - T2 & FLAIR - cannot reliably pick up these cortical lesions due to their small size and lower contrast compared with the surrounding normal-appearing white matter. DIR sequence by attenuating the CSF and the white-matter achieves higher contrast and superior delineation between grey and white matter. It detects more cortical lesions than conventional T2 and even FLAIR images with the added advantage of its apparent potential for better differentiation between mixed white-grey matter lesions and juxta cortical lesions. It can detect periventricular white-matter better than the other sequences. The findings on DIR can better explain the physical and cognitive dysfunction in patients with MS. Even for spinal cord lesions, the DIR sequence has been found to be superior to routinely used sequences by demonstrating more lesions, especially in the cervical cord.
In the present article, the authors Kulkarni, et al., in simple words, describe the basics of this sequence followed by its distinct advantage over other sequences in the evaluation of craniospinal lesions of MS with their personal experience. The authors have emphasised that the role of DIR is not limited to MS, but it also proves superior in conditions like focal cortical dysplasia, hippocampal sclerosis, & demyelination of optic nerves.
Though not mentioned in the article, the sequence has also been found to be useful in hyperacute infarcts DIR has been found to have a distinct advantage over T2 & FLAIR and is equal to, if not better than, diffusion-weighted imaging. Unlike DWI it does not have the problem of susceptibility artefacts giving it a distinct advantage in the evaluation of infratentorial infarcts. However, more work is needed before we can recommend replacing DWI with DIR in suspected ischaemia.
The sequence is not perfect and has few limitations, such as a long scan time and flow artefacts especially in the infratentorial compartment, periventricular white matter, choroid plexus, and periaqueductal region. The major disadvantages of the sequence are well highlighted by the authors.
To summarise - DIR, while not perfect, is a useful sequence and definitely superior to T2 and FLAIR images for detecting lesions in locations like cortical, periventricular, and infratentorial areas. It should preferably be added to MRI protocols and can even replace FLAIR sequence for evaluation of MS. It scores over other sequences in detecting MS plaques in the cervical cord, focal cortical dysplasias in the brain. More studies are required to establish and substantiate its advantages in conditions like pediatric epilepsy and stroke.
| » References|| |
Kulkarni S, Kulkarni MM, Patankar A, Watve A. Role of Double Inversion Recovery Sequence in Neuro-imaging on 3 Tesla MRI. Neurol India 2021;69;394-6.
Weaam H, Wessam F, Walaa M, Galal E. Diagnostic accuracy of double inversion recovery in delineation of multiple sclerosis lesions and its clinical correlation with expanded disability scoring system. Egypt J Radiol Nucl Med 2019;50:114-22.
Maura E Ryan. Utility of Double Inversion Recovery Sequences in MRI. Pediatr Neurol Briefs 2016;30:26.
Choi NY, Park S, Lee CM, Ryu C, Jahng G. The Role Of Double Inversion Recovery Imaging In Acute Ischemic Stroke. Investigative Magnetic Resonance Imaging 2019;23: 210-9.