Transient disappearance of microbleeds in the subacute period based on T2*-weighted gradient echo imaging in traumatic brain injury

Watanabe, Jun; Maruya, Jun; Kanemaru, Yu; Miyauchi, Takaharu; Nishimaki, Keiichi

doi:10.1007/s00701-016-2805-5

Cited by 12 publications

(14 citation statements)

References 11 publications

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“…This observation remains to be replicated in other domains and larger-scale studies, yet it indicates that MR imaging should ideally be performed early after mild traumatic brain injury, notably because the detection rate of nonhemorrhagic diffuse axonal injury features (eg, areas of diffusion restriction) is also higher in the immediate posttraumatic period. Moreover, intriguing recent reports indicate that CMBs may show dynamic changes after the acute injury, including growth (80) and temporary disappearance (81). These reports further support that the timing of imaging is important, but this needs confirmation in future studies.…”

Section: Traumatic Brain Injurymentioning

confidence: 66%

Cerebral Microbleeds: Imaging and Clinical Significance

Haller¹,

Vernooij²,

Kuijer³

et al. 2018

Radiology

239

161

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Cerebral microbleeds (CMBs), also referred to as microhemorrhages, appear on magnetic resonance (MR) images as hypointense foci notably at T2*-weighted or susceptibility-weighted (SW) imaging. CMBs are detected with increasing frequency because of the more widespread use of high magnetic field strength and of newer dedicated MR imaging techniques such as three-dimensional gradient-echo T2*-weighted and SW imaging. The imaging appearance of CMBs is mainly because of changes in local magnetic susceptibility and reflects the pathologic iron accumulation, most often in perivascular macrophages, because of vasculopathy. CMBs are depicted with a true-positive rate of 48%-89% at 1.5 T or 3.0 T and T2*-weighted or SW imaging across a wide range of diseases. False-positive "mimics" of CMBs occur at a rate of 11%-24% and include microdissections, microaneurysms, and microcalcifications; the latter can be differentiated by using phase images. Compared with postmortem histopathologic analysis, at least half of CMBs are missed with premortem clinical MR imaging. In general, CMB detection rate increases with field strength, with the use of three-dimensional sequences, and with postprocessing methods that use local perturbations of the MR phase to enhance T2* contrast. Because of the more widespread availability of high-field-strength MR imaging systems and growing use of SW imaging, CMBs are increasingly recognized in normal aging, and are even more common in various disorders such as Alzheimer dementia, cerebral amyloid angiopathy, stroke, and trauma. Rare causes include endocarditis, cerebral autosomal dominant arteriopathy with subcortical infarcts, leukoencephalopathy, and radiation therapy. The presence of CMBs in patients with stroke is increasingly recognized as a marker of worse outcome. Finally, guidelines for adjustment of anticoagulant therapy in patients with CMBs are under development. RSNA, 2018.

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Section: Traumatic Brain Injurymentioning

confidence: 66%

Cerebral Microbleeds: Imaging and Clinical Significance

Haller¹,

Vernooij²,

Kuijer³

et al. 2018

Radiology

239

161

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“…Similar changes in CMB volume have previously been reported during the acute and chronic phases following a traumatic brain injury. [24][25][26] Liu et al found a dramatic decrease in quantitative measures of CMBs from serial imaging acquired beyond 2 years postinjury, 24 while Lawrence et al and Watanabe et al reported the appearance of CMBs within the first few hours following injury; CMBs showed reductions in volume over a 2-15-day period that were associated with patient recovery. 25,26 Thus, identifying treatment strategies to accelerate the mechanism through which CMBs decrease in size may be a viable alternative for minimizing CMBassociated deficits.…”

Section: Discussionmentioning

confidence: 99%

Risk factors of radiotherapy‐induced cerebral microbleeds and serial analysis of their size compared with white matter changes: A 7T MRI study in 113 adult patients with brain tumors

Morrison

Hess

Clarke

et al. 2019

Magnetic Resonance Imaging

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Background Although radiation therapy (RT) contributes to survival benefit in many brain tumor patients, it has also been associated with long‐term brain injury. Cerebral microbleeds (CMBs) represent an important manifestation of radiation‐related injury. Purpose To characterize the change in size and number of CMBs over time and to evaluate their relationship to white matter structural integrity as measured using diffusion MRI indices. Study Type Longitudinal, retrospective, human cohort. Population In all, 113 brain tumor patients including patients treated with focal RT (n = 91, 80.5%) and a subset of nonirradiated controls (n = 22, 19.5%). Field Strength/Sequence Single and multiecho susceptibility‐weighted imaging (SWI) and multiband, shell, and direction diffusion tensor imaging (DTI) at 7 T. Assessment Patients were scanned either once or serially. CMBs were detected and quantified on SWI images using a semiautomated approach. Local and global fractional anisotropy (FA) were measured from DTI data for a subset of 35 patients. Statistical Tests Potential risk factors for CMB development were determined by multivariate linear regression and using linear mixed‐effect models. Longitudinal FA was quantitatively and qualitatively evaluated for trends. Results All patients scanned at 1 or more years post‐RT had CMBs. A history of multiple surgical resections was a risk factor for development of CMBs. The total number and volume of CMBs increased by 18% and 11% per year, respectively, although individual CMBs decreased in volume over time. Simultaneous to these microvascular changes, FA decreased by a median of 6.5% per year. While the majority of nonirradiated controls had no CMBs, four control patients presented with fewer than five CMBs. Data Conclusion Identifying patients who are at the greatest risk for CMB development, with its likely associated long‐term cognitive impairment, is an important step towards developing and piloting preventative and/or rehabilitative measures for patients undergoing RT. Level of Evidence: 3 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2019;50:868–877.

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“…Two recent preliminary studies have highlighted the potential for detection of TCMBs in the first few days after injury [18] [19] . The modest number of patients recruited provided only preliminary indication of a link between TCMB severity and clinical outcome.…”

Section: Introductionmentioning

confidence: 99%

“…Both studies suggested that lesions could be identified, and will evolve, in the first week following trauma. One study suggested an increase in lesion volume and an apparent reduction in number due to lesion coalescence [18] ; the other showed a reduction in lesion volume in the same timeframe [19] . The authors of the first study suggested that an increase in lesion volume could be explained by progressive microvascular damage.…”

Section: Introductionmentioning

confidence: 99%