====== Diffusion tensor imaging for Brainstem cavernous malformation ======

{{rss>https://pubmed.ncbi.nlm.nih.gov/rss/search/1-ajL1qsWMIMAykJki-upaTYhI2V8KOQ-zHhQXLhMbYGH3_QjB/?limit=15&utm_campaign=pubmed-2&fc=20230517044548}}
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The utilization of [[preoperative]] [[diffusion tensor imaging]] significantly increased the proportion of improved patients and decreased the proportion of worsened patients. However, further controlled [[research]] is needed to draw a definite [[conclusion]] about the usefulness of its role
((Al-Salihi MM, Al-Jebur MS, Al-Salihi Y, Saha R, Daie MM, Rahman MM, Ayyad A. Diffusion Tensor Imaging with Tractography in Surgical Resection of Brainstem Cavernous Malformations: A Systematic Review and Meta-analysis. Int J Neurosci. 2023 May 16:1-30. doi: 10.1080/00207454.2023.2214696. Epub ahead of print. PMID: 37194114.)).
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A study aimed to systematically review the literature to determine the clinical utility and perspectives of [[diffusion tensor imaging]] (DTI) in the [[management]] of patients with [[brainstem cavernous malformation]]s (BSCMs). [[PubMed]], [[Embase]], and [[Cochrane]] were searched for English-language articles published until May 10, 2021. Clinical studies and case series describing DTI-based evaluation of patients with BSCMs were included. Fourteen articles were included. Preoperative DTI enabled to adjustment of the surgical approach and choose a [[brainstem safe entry zone]] in deep-seated BSCMs. Preoperatively lower [[fractional anisotropy]] (FA) of the [[corticospinal tract]] (CST) correlated with the severity of CST injury and motor deficits. Postoperatively increased FA and decreased [[apparent diffusion coefficient]] (ADC) corresponded with the normalization of the perilesional CST, indicating motor improvement. The positive (PPV) and negative [[predictive value]] (NPV) of qualitative DTI ranged from 20 to 75% and from 66.6 to 100%, respectively. The presence of preoperative and postoperative motor deficits was associated with a higher preoperative resting motor threshold (RMT) and lower FA. A higher preoperative [[corticospinal tract]] score was indicative of a lower preoperative and follow-up Medical Research Council (MRC) grade. DTI facilitated the determination of a surgical trajectory with minimized risk of WMTs damage. Preoperative FA and RMT might indicate the severity of preoperative and postoperative motor deficits. Preoperative CST score can reliably reflect patients' preoperative and follow-up motor status. Due to high NPV, normal CST morphology might predict intact neurological outcomes. Contrarily, sparse and relatively low PPV limits the reliable prediction of neurological deficits
((Rogalska M, Antkowiak L, Mandera M. Clinical application of [[diffusion tensor imaging]] and [[fiber]] [[tractography]] in the management of [[brainstem cavernous malformation]]s: a [[systematic review]]. Neurosurg Rev. 2022 Feb 25. doi: 10.1007/s10143-022-01759-7. Epub ahead of print. PMID: 35211879.)).
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In 2016 Januszewski et al. compared with the standard magnetic resonance imaging, DTI provided improved visualization of cavernous malformation involvement in eloquent fiber tracts of the brainstem. This additional information might help in selecting a more appropriate surgical trajectory in selected lesions. Larger patient cohorts are needed to assess the effect of this modality in patients' outcome
((Januszewski J, Albert L, Black K, Dehdashti AR. The Usefulness of Diffusion Tensor Imaging and Tractography in Surgery of Brainstem Cavernous Malformations. World Neurosurg. 2016 Sep;93:377-88. doi: 10.1016/j.wneu.2016.06.019. Epub 2016 Jun 14. PMID: 27312394.)).
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Positive findings on [[DTT]] such as [[fiber tract]] deviation, deformation, disruption or interruption should be taken cautiously before drawing conclusions of clinically relevant damage of [[white matter tract]]s
((Topcuoglu OM, Yaltirik K, Firat Z, Sarsilmaz A, Harput V, Sarikaya B, Ture U. 
Limited Positive Predictive Value of Diffusion Tensor Tractography in Determining
Clinically Relevant White Matter Damage in Brainstem Cavernous Malformations: A
Retrospective Study in a Single Center Surgical Cohort. J Neuroradiol. 2019 Sep
17. pii: S0150-9861(19)30438-9. doi: 10.1016/j.neurad.2019.07.005. [Epub ahead of
print] PubMed PMID: 31539583.
)).

Preoperative [[diffusion tensor imaging]] may influence the selection of surgical approach or brainstem entry zones, especially in deep-seated lesions without pial or ependymal presentation. DTI/DTT findings may allow for more aggressive management of lesions previously considered surgically inaccessible. Preoperative DTI/DTT changes do not appear to correlate with functional postoperative outcome in long-term follow-up
((Flores BC, Whittemore AR, Samson DS, Barnett SL. The utility of preoperative
diffusion tensor imaging in the surgical management of brainstem cavernous
malformations. J Neurosurg. 2015 Mar;122(3):653-62. doi:
10.3171/2014.11.JNS13680. Epub 2015 Jan 9. PubMed PMID: 25574568.))

Intact [[corticospinal tract]] (CST) morphology in [[diffusion tensor imaging]] DTI predicts a favorable postoperative outcome in patients with BSC. Interrupted CSTs and decreased [[Fractional anisotropy]] (FA)-values correlate well within lesion level, nevertheless morphologic characteristics and diffusion parameter changes cannot predict poor prognosis. Caudal and rostral diffusion parameters can provide more information of the integrity of CSTs compared with morphological study alone
((Yao Y, Ulrich NH, Guggenberger R, Alzarhani YA, Bertalanffy H, Kollias SS.
Quantification of corticospinal tracts with diffusion tensor imaging in brainstem
surgery: Prognostic value in 14 consecutive cases at 3T-MRI. World Neurosurg.
2015 Mar 5. pii: S1878-8750(15)00067-4. doi: 10.1016/j.wneu.2015.01.045. [Epub
ahead of print] Review. PubMed PMID: 25749578.
)).

Hemorrhagic brainstem CMs can disrupt and displace perilesional [[white matter tract]]s with the latter occurring in unpredictable directions. This requires the use of tractography to accurately define their orientation to optimize surgical entry point, minimize morbidity, and enhance neurological outcomes. Observed [[anisotropy]] decreases in the perilesional segments are consistent with neural injury following hemorrhagic insults. A model using these values in different CST segments can be used to longitudinally monitor its craniocaudal integrity. Diffusion connectometry is a complementary approach providing longitudinal information on the rostrocaudal involvement of the CST
((Faraji AH, Abhinav K, Jarbo K, Yeh FC, Shin SS, Pathak S, Hirsch BE, Schneider
W, Fernandez-Miranda JC, Friedlander RM. Longitudinal evaluation of corticospinal
tract in patients with resected brainstem cavernous malformations using
high-definition fiber tractography and diffusion connectometry analysis:
preliminary experience. J Neurosurg. 2015 Jun 5:1-12. [Epub ahead of print]
PubMed PMID: 26047420.
)).
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In 2007 compared with the information provided by conventional [[MR imaging]], DTI and WMT provided superior quantification and visualization of lesion involvement in eloquent [[fiber tract]]s of the [[brainstem]]. Moreover, DTI and WMT were found to be beneficial for white matter recognition in the neurosurgical planning and postoperative assessment of brainstem lesions
((Chen X, Weigel D, Ganslandt O, Buchfelder M, Nimsky C. Diffusion tensor imaging and white matter tractography in patients with brainstem lesions. Acta Neurochir (Wien). 2007 Nov;149(11):1117-31; discussion 1131. doi: 10.1007/s00701-007-1282-2. Epub 2007 Aug 23. PMID: 17712509.)).