3D Double Inversion Recovery Sequence Research Articles

Single-slab 3D double inversion recovery for magnetic resonance brain imaging in clinically healthy dogs.

In veterinary medicine, magnetic resonance imaging (MRI) is widely utilized for brain imaging. But the complex structures of brain tissues can give rise to artifacts such as partial volume averaging in conventional sequences. To address this issue, several studies about double inversion recovery (DIR) sequences have been conducted in human medicine. However, published clinical studies about brain MRI using DIR sequences in dogs are currently lacking. The purpose of this study was to evaluate the magnetic resonance features of single-slab 3D DIR sequences in the normal canine brain. Five healthy Beagle dogs were examined and the following pulse sequences were acquired for each: (1) spin-echo T2-weighted (T2W), (2) fluid attenuated inversion recovery (FLAIR), (3) gray matter (GM) selective, and (4) white matter (WM) selective single-slab 3D DIR sequence. For qualitative analysis, the distinction between gray and white matter of the cerebral cortex, presence and severity of the image artifacts were assessed for each pulse sequence. In addition, reconstructed images of single-slab 3D DIR sequences were qualitatively evaluated. For quantitative analysis, contrast ratios (CRs), signal-to-noise ratios (SNRs), and contrast-to-noise ratios (CNRs) of the GM, WM and cerebrospinal fluid (CSF) were measured for each pulse sequence. GM selective 3D DIR was superior to T2W and FLAIR in delineating the boundaries between GM and WM in the overall brain area. Whereas WM selective 3D DIR provided better gray-white matter distinction of the cerebral cortex than T2W and FLAIR at the level of the medulla oblongata, where T2W and FLAIR images exhibited severe partial volume averaging artifacts. In general, the 3D DIR images demonstrated fewer artifacts compared to other sequences, and the reconstructed sagittal and dorsal images of these sequences maintained same spatial resolution as the original transverse images without any image degradation. Both gray and white matter selective 3D DIR sequences effectively suppressed unwanted signals, thereby providing high contrast between gray and white matter. Findings from this study could serve as a foundation for further studies on DIR sequences for the evaluation of brain diseases in dogs.

Utility of 3D Double Inversion Recovery Sequence in Paediatric Epilepsy and its Comparison to 3D Fluid Attenuation Inversion Recovery Sequence and T1 Inversion Recovery Sequence : A Cross-sectional Study

Introduction: Epilepsy is a disease with predisposition to generate epileptic seizures, associated with neurobiological, cognitive, psychological, and social consequences. Nearly 30% of children undergoing medical treatment for epilepsy become refractive to the treatment. For those children, the ability to find the epileptogenic area is higher with Magnetic Resonance Imaging (MRI) of the brain. The traditional 2D spin-echo sequences used in epilepsy protocol for adults cannot be used alone in paediatric structural neuroimaging. Additional sequences are needed to identify epileptogenic areas due to differences in myelination. Here, present study compared the role of three volumetric sequences 3D-Fluid Attenuated Inversion Recovery (FLAIR) , 3D-T1 weighted Inversion Recovery (T1-IR) and 3D-Double Inversion Recovery (DIR) for paediatric epilepsy as part of structural neuroimaging. Aim: To assess the utility of 3D-DIR in paediatric epilepsy disorders and localisation of epileptogenic foci in brain, congenital malformations of brain and compare its findings with 3D-FLAIR and 3D-T1-IR. Materials and Methods: The present study was a cross-sectional study of children diagnosed with paediatric epilepsy, who were evaluated with MRI brain at Stanley Medical College, Chennai, Tamil Nadu, India, between April 2020 to April 2021 with three sequences, 3D-DIR, 3D-T1-IR and 3D-FLAIR. Lesions of atleast 3 mm in diameter were identified as foci of high signal intensity and counted in each of the three sequences separately and classified according to their location. Then, average signal intensities of the lesions were calculated manually on each of sequences using Region of Interest (ROI) analysis which had a mean size of 3 mm2 . Then the Signal-to-Noise Ratio (SNR), Contrast to-Noise Ratio (CNR), Contrast Ratio (CR), and Asymmetry Signal Ratio (ASR) were calculated. Results: Evaluation was done on 51 paediatric epilepsy patients and showed the total number of lesions detected (208 lesions) and measured contrast parameters (CR, CNR and ASR) which were found to be significantly higher in 3D-DIR, showed higher detection of the intracortical and white matter lesions than 3DFLAIR and 3D-T1-IR. SNR was higher in 3D-FLAIR. Conclusion: Present study concluded that the greatest value of the DIR sequence has a higher ability in detecting epileptogenic foci and congenital malformations of the lesions in comparison with FLAIR and T1-IR.

Improving Detection of Multiple Sclerosis Lesions in the Posterior Fossa Using an Optimized 3D-FLAIR Sequence at 3T.

There is no consensus regarding the best MR imaging sequence for detecting MS lesions. The aim of our study was to assess the diagnostic value of optimized 3D-FLAIR in the detection of infratentorial MS lesions compared with an axial T2-weighted imaging, a 3D-FLAIR with factory settings, and a 3D double inversion recovery sequence. In this prospective study, 27 patients with confirmed MS were included. Two radiologists blinded to clinical data independently read the following sequences: axial T2WI, 3D double inversion recovery, standard 3D-FLAIR with factory settings, and optimized 3D-FLAIR. The main judgment criterion was the overall number of high-signal-intensity lesions in the posterior fossa; secondary objectives were the assessment of the reading confidence and the measurement of the contrast. A nonparametric Wilcoxon test was used to compare the MR images. Twenty-two patients had at least 1 lesion in the posterior fossa. The optimized FLAIR sequence detected significantly more posterior fossa lesions than any other sequence: 7.5 versus 5.8, 4.8, and 4.1 (P values of .04, .03, and .03) with the T2WI, the double inversion recovery, and the standard FLAIR, respectively. The reading confidence index was significantly higher with the optimized FLAIR, and the contrast was significantly higher with the optimized FLAIR than with the standard FLAIR and the double inversion recovery. An optimized 3D-FLAIR sequence improved posterior fossa lesion detection in patients with MS.

Pre- and Postcontrast 3D Double Inversion Recovery Sequence in Multiple Sclerosis: A Simple and Effective MR Imaging Protocol.

The double inversion recovery sequence is known to be very sensitive and specific for MS-related lesions. Our aim was to compare the sensitivity of pre- and postcontrast images of 3D double inversion recovery and conventional 3D T1-weighted images for the detection of contrast-enhancing MS-related lesions in the brain to analyze whether double inversion recovery could be as effective as T1WI. A postcontrast 3D double inversion recovery sequence was acquired in addition to the standard MR imaging protocol at 3T, including pre- and postcontrast 3D T1WI sequences as well as precontrast double inversion recovery of 45 consecutive patients with MS or clinically isolated syndrome between June and December 2013. Two neuroradiologists independently assessed precontrast, postcontrast, and subtraction images of double inversion recovery as well as T1WI to count the number of contrast-enhancing lesions. Afterward, a consensus reading was performed. Lin concordance was calculated between both radiologists, and differences in lesion detectability were assessed with the Student t test. Additionally, the contrast-to-noise ratio was calculated. Significantly more contrast-enhancing lesions could be detected with double inversion recovery compared with T1WI (16%, 214 versus 185, P = .007). The concordance between both radiologists was almost perfect (ρc = 0.94 for T1WI and ρc = 0.98 for double inversion recovery, respectively). The contrast-to-noise ratio was significantly higher in double inversion recovery subtraction images compared with T1-weighted subtraction images (double inversion recovery, 14.3 ± 5.5; T1WI, 6.3 ± 7.1; P < .001). Pre- and postcontrast double inversion recovery enables better detection of contrast-enhancing lesions in MS in the brain compared with T1WI and may be considered an alternative to the standard MR imaging protocol.

How Common Is Signal-Intensity Increase in Optic Nerve Segments on 3D Double Inversion Recovery Sequences in Visually Asymptomatic Patients with Multiple Sclerosis?

In postmortem studies, subclinical optic nerve demyelination is very common in patients with MS but radiologic demonstration is difficult and mainly based on STIR T2WI. Our aim was to evaluate 3D double inversion recovery MR imaging for the detection of subclinical demyelinating lesions within optic nerve segments. The signal intensities in 4 different optic nerve segments (ie, retrobulbar, canalicular, prechiasmatic, and chiasm) were evaluated on 3D double inversion recovery MR imaging in 95 patients with MS without visual symptoms within the past 3 years and in 50 patients without optic nerve pathology. We compared the signal intensities with those of the adjacent lateral rectus muscle. The evaluation was performed by a student group and an expert neuroradiologist. Statistical evaluation (the Cohen κ test) was performed. On the 3D double inversion recovery sequence, optic nerve segments in the comparison group were all hypointense, and an isointense nerve sheath surrounded the retrobulbar nerve segment. At least 1 optic nerve segment was isointense or hyperintense in 68 patients (72%) in the group with MS on the basis of the results of the expert neuroradiologist. Student raters were able to correctly identify optic nerve hypersignal in 97%. A hypersignal in at least 1 optic nerve segment on the 3D double inversion recovery sequence compared with hyposignal in optic nerve segments in the comparison group was very common in visually asymptomatic patients with MS. The signal-intensity rating of optic nerve segments could also be performed by inexperienced student readers.

Double inversion recovery MR sequence for the detection of subacute subarachnoid hemorrhage.

The diagnosis of subacute subarachnoid hemorrhage is important because rebleeding may occur with subsequent life-threatening hemorrhage. Our aim was to determine the sensitivity of the 3D double inversion recovery sequence compared with CT, 2D and 3D FLAIR, 2D T2*, and 3D SWI sequences for the detection of subacute SAH. This prospective study included 25 patients with a CT-proved acute SAH. Brain imaging was repeated between days 14 and 16 (mean, 14.75 days) after clinical onset and included MR imaging (2D and 3D FLAIR, 2D T2*, SWI, and 3D double inversion recovery) after CT (median delay, 3 hours; range, 2-5 hours). A control group of 20 healthy volunteers was used for comparison. MR images and CT scans were analyzed independently in a randomized order by 3 blinded readers. For each subject, the presence or absence of hemorrhage was assessed in 4 subarachnoid areas (basal cisterns, Sylvian fissures, interhemispheric fissure, and convexity) and in brain ventricles. The diagnosis of subacute SAH was defined by the presence of at least 1 subarachnoid area with hemorrhage. For the diagnosis of subacute SAH, the double inversion recovery sequence had a higher sensitivity compared with CT (P < .001), 2D FLAIR (P = .005), T2* (P = .02), SWI, and 3D FLAIR (P = .03) sequences. Hemorrhage was present for all patients in the interhemispheric fissure on double inversion recovery images, while no signal abnormality was noted in healthy volunteers. Interobserver agreement was excellent with double inversion recovery. Our study showed that the double inversion recovery sequence has a higher sensitivity for the detection of subacute SAH than CT, 2D or 3D FLAIR, 2D T2*, and SWI.

Double inversion recovery sequence of the cervical spinal cord in multiple sclerosis and related inflammatory diseases.

MR imaging plays an important role in diagnosing MS and other related inflammatory diseases; however, imaging of the spinal cord is still challenging. We hypothesized that a 3D double inversion recovery sequence for cervical spinal cord imaging would be more sensitive in detecting inflammatory lesions than a conventional 2D T2-weighted TSE sequence at 3T. On a 3T MR imaging scanner, we examined 30 patients with suspected or established MS (MS, n = 16; clinically isolated syndrome, n = 12; isolated myelitis, n = 2) and 10 healthy controls. Newly developed 3D double inversion recovery and conventional 2D axial and sagittal T2-weighted TSE images of the cervical spinal cord were acquired. Two blinded neuroradiologists independently assessed the scans in pseudorandomized order for lesion numbers and rated lesion visibility and overall image quality on 5-point scales. A subsequent consensus reading delivered definite lesion counts. Standardized contrast-to-noise ratios were calculated in representative lesions of each patient. Overall, 28% more lesions could be detected with 3D double inversion recovery than with conventional T2WI (119 versus 93, P < .002). On average, the standardized contrast-to-noise ratio was significantly higher (P < .001) in double inversion recovery than in T2WI. Lesion visibility was rated significantly higher (P < .001) in double inversion recovery compared with T2WI despite lower image quality. The novel 3D double inversion recovery sequence allowed better detection of lesions in MS and related inflammatory diseases of the cervical spinal cord, compared with conventional 2D T2WI.

Contribution of cortical and white matter lesions to cognitive impairment in multiple sclerosis

Background: Cortical lesions (CLs) have been reported to be a better predictor for cognitive impairment than white matter (WM) lesions in relapsing–remitting multiple sclerosis (RRMS). Objectives: The objectives of this article are to investigate the contribution of CLs and WM lesions to cognitive impairment in 91 patients with MS and clinically isolated syndrome, and to test potential associations of CLs and WM lesions with fatigue and depression. Methods: Lesions were scored and segmented on 3D double inversion recovery sequences, according to their location (cortical, WM). Normalised grey matter volume was also determined. Cognitive performance was assessed with the SDMT and PASAT-3, fatigue with the FSMC and depression with the German version of the CES-D. Results: CL volume did not correlate with fatigue or depression, but correlated significantly with both neuropsychological outcome measures: PASAT-3 (r = −0.275, p = 0.009) and SDMT (r = −0.377, p < 0.001). Multiple regression analyses with age, WM lesions, CLs and GM volume as independent variables, however, did not reveal CL volume as a significant predictor of neuropsychological outcomes, whereas WM lesion volume significantly predicted SDMT and by trend PASAT performance. Conclusions: These findings suggest a role of WM lesions in the development of cognitive deficits, especially information-processing speed, which may be higher than previously assumed. Abbreviations: CES-D: Center for Epidemiologic Studies Depression scale (ADS-L: Allgemeine Depressions Skala-L, German version of CES-D), CIS: clinically isolated syndrome, CL: cortical lesion, DIR: double inversion recovery, EDSS: Expanded Disability Status Scale, FSMC: fatigue scale for motor and cognitive functions, GM: grey matter, MRI: magnetic resonance imaging, MS: multiple sclerosis, PASAT-3: paced auditory serial addition test 3s, PPMS: primary progressive multiple sclerosis, RRMS: relapsing–remitting multiple sclerosis, SDMT: symbol digit modalities test, SPM: statistical parametric mapping, SPMS: secondary progressive multiple sclerosis, WM: white matter

Intracortical Lesions in Multiple Sclerosis: Improved Detection with 3D Double Inversion-Recovery MR Imaging

To prospectively compare the depiction of intracortical lesions by using multislab three-dimensional (3D) double inversion-recovery (DIR), multislab 3D fluid-attenuated inversion-recovery (FLAIR), and T2-weighted spin-echo (SE) magnetic resonance (MR) imaging in patients with multiple sclerosis. Local ethics review board approval and informed consent were obtained. Conventional T2-weighted SE and multislab 3D FLAIR and DIR images were acquired in 10 patients with multiple sclerosis (five women, five men) and 11 age-matched healthy control subjects (seven women, four men). Mean age was 40 years (range, 25-54 years) in patients and 34 years (range, 24-55 years) in control subjects. Lesions were classified according to seven anatomic regions: intracortical, mixed white matter-gray matter, juxtacortical, deep gray matter, periventricular white matter, deep white matter, and infratentorial lesions. The numbers of lesions per category were compared between techniques (Dunnett-corrected analysis of variance). Gain or loss (with 95% confidence intervals [CIs]) of numbers of lesions detected at 3D DIR imaging was calculated in comparison with those detected at T2-weighted SE and 3D FLAIR imaging. Total number of lesions did not differ between 3D DIR and 3D FLAIR sequences, but the 3D DIR sequence showed a gain of 21% (95% CI: 4%, 41%) in comparison with the T2-weighted SE sequence. Because of high gray matter-white matter contrast, DIR images depicted more intracortical lesions (80 lesions in 10 patients) than both SE (10 lesions) and FLAIR (31 lesions) images; gains with DIR were 538% (95% CI: 191%, 1297%) and 152% (95% CI: 15%, 453%) compared with SE and FLAIR, respectively. Only four intracortical lesions were detected in control subjects. Also, DIR imaging enabled a better definition of mixed white matter-gray matter lesions because of greater contrast between the lesion and its surroundings. MR imaging with 3D DIR enables increased intracortical lesion detection in the multiple sclerosis brain, as well as improved distinction between juxtacortical and white matter-gray matter lesions.

Renal artery stenosis due to abdominal aortic aneurysm.

<h3>BACKGROUND AND PURPOSE:</h3> The diagnosis of subacute subarachnoid hemorrhage is important because rebleeding may occur with subsequent life-threatening hemorrhage. Our aim was to determine the sensitivity of the 3D double inversion recovery sequence compared with CT, 2D and 3D FLAIR, 2D T2*, and 3D SWI sequences for the detection of subacute SAH. <h3>MATERIALS AND METHODS:</h3> This prospective study included 25 patients with a CT-proved acute SAH. Brain imaging was repeated between days 14 and 16 (mean, 14.75 days) after clinical onset and included MR imaging (2D and 3D FLAIR, 2D T2*, SWI, and 3D double inversion recovery) after CT (median delay, 3 hours; range, 2–5 hours). A control group of 20 healthy volunteers was used for comparison. MR images and CT scans were analyzed independently in a randomized order by 3 blinded readers. For each subject, the presence or absence of hemorrhage was assessed in 4 subarachnoid areas (basal cisterns, Sylvian fissures, interhemispheric fissure, and convexity) and in brain ventricles. The diagnosis of subacute SAH was defined by the presence of at least 1 subarachnoid area with hemorrhage. <h3>RESULTS:</h3> For the diagnosis of subacute SAH, the double inversion recovery sequence had a higher sensitivity compared with CT (<i>P</i> &lt; .001), 2D FLAIR (<i>P</i> = .005), T2* (<i>P</i> = .02), SWI, and 3D FLAIR (<i>P</i> = .03) sequences. Hemorrhage was present for all patients in the interhemispheric fissure on double inversion recovery images, while no signal abnormality was noted in healthy volunteers. Interobserver agreement was excellent with double inversion recovery. <h3>CONCLUSIONS:</h3> Our study showed that the double inversion recovery sequence has a higher sensitivity for the detection of subacute SAH than CT, 2D or 3D FLAIR, 2D T2*, and SWI.