The radiological interpretation of possible microbleeds after moderate or severe traumatic brain injury: a longitudinal study.

INTRODUCTION: In order to augment the certainty of the radiological interpretation of "possible microbleeds" after traumatic brain injury (TBI), we assessed their longitudinal evolution on 3-T SWI in patients with moderate/severe TBI. METHODS: Standardized 3-T SWI and T1-weighted imaging were obtained 3 and 26 weeks after TBI in 31 patients. Their microbleeds were computer-aided detected and classified by a neuroradiologist as no, possible, or definite at baseline and follow-up, separately (single-scan evaluation). Thereafter, the classifications were re-evaluated after comparison between the time-points (post-comparison evaluation). We selected the possible microbleeds at baseline at single-scan evaluation and recorded their post-comparison classification at follow-up. RESULTS: Of the 1038 microbleeds at baseline, 173 were possible microbleeds. Of these, 53.8% corresponded to no microbleed at follow-up. At follow-up, 30.6% were possible and 15.6% were definite. Of the 120 differences between baseline and follow-up, 10% showed evidence of a pathophysiological change over time. Proximity to extra-axial injury and proximity to definite microbleeds were independently predictive of becoming a definite microbleed at follow-up. The reclassification level differed between anatomical locations. CONCLUSIONS: Our findings support disregarding possible microbleeds in the absence of clinical consequences. In selected cases, however, a follow-up SWI-scan could be considered to exclude evolution into a definite microbleed.

Observer variability of reference tissue selection for relativecerebral blood volume measurements in glioma patients.

OBJECTIVES: To assess observer variability of different reference tissues used for relative CBV (rCBV) measurements in DSC-MRI of glioma patients. METHODS: In this retrospective study, three observers measured rCBV in DSC-MR images of 44 glioma patients on two occasions. rCBV is calculated by the CBV in the tumour hotspot/the CBV of a reference tissue at the contralateral side for normalization. One observer annotated the tumour hotspot that was kept constant for all measurements. All observers annotated eight reference tissues of normal white and grey matter. Observer variability was evaluated using the intraclass correlation coefficient (ICC), coefficient of variation (CV) and Bland-Altman analyses. RESULTS: For intra-observer, the ICC ranged from 0.50-0.97 (fair-excellent) for all reference tissues. The CV ranged from 5.1-22.1 % for all reference tissues and observers. For inter-observer, the ICC for all pairwise observer combinations ranged from 0.44-0.92 (poor-excellent). The CV ranged from 8.1-31.1 %. Centrum semiovale was the only reference tissue that showed excellent intra- and inter-observer agreement (ICC>0.85) and lowest CVs (<12.5 %). Bland-Altman analyses showed that mean differences for centrum semiovale were close to zero. CONCLUSION: Selecting contralateral centrum semiovale as reference tissue for rCBV provides the lowest observer variability. KEY POINTS: • Reference tissue selection for rCBV measurements adds variability to rCBV measurements. • rCBV measurements vary depending on the choice of reference tissue. • Observer variability of reference tissue selection varies between poor and excellent. • Centrum semiovale as reference tissue for rCBV provides the lowest observer variability.

Executive Function Declines in the First 6 Months After a Transient Ischemic Attack or Transient Neurological Attack.

BACKGROUND AND PURPOSE: Although by definition transient, both transient ischemic attack (TIA) and transient neurological attack (TNA) are associated with cognitive impairment. Determinants and course of cognitive function afterward are, however, unclear. We prospectively determined cognitive performance after TIA and TNA in relation to clinical diagnosis and diffusion-weighted imaging (DWI) results. METHODS: TIA and TNA patients aged ≥45 years without prior stroke or dementia underwent comprehensive cognitive assessment and magnetic resonance imaging within 7 days after the qualifying event. Cognitive tests were repeated after 6 months. Domain-specific compound z scores based on the baseline mean and SD were calculated. Repeated-measures analysis was used to test for differences in domain-specific cognitive performance over time between DWI-positive and DWI-negative patients, as well as between TIA and TNA patients. RESULTS: One hundred twenty-one patients were included (mean age (SD), 64.6 years (9.2 years), 60% TIA and 40% TNA) of whom 32 (26%) had a DWI lesion. Executive function performance decreased over time (mean change in compound score -0.23; P=0.01 adjusted for age, sex, education), whereas attention improved (0.11; P=0.02), and information processing speed and episodic memory remained unchanged. Patients with a DWI lesion had worse executive function at baseline than those without a DWI lesion (compound scores -0.26 versus 0.08; P=0.048), which persisted throughout the study period (P=0.04). Clinical diagnosis (TIA or TNA) was not related to cognitive function over time. CONCLUSIONS: Executive function declines during the first 6 months after TIA or TNA. Patients with an initial DWI lesion have persisting worse executive function than those without.

Diffusion-weighted imaging in transient neurological attacks.

Transient ischemic attack (TIA) can be difficult to diagnose. Episodes of acute atypical or nonfocal neurological symptoms, referred to as transient neurological attack (TNA), are as prevalent as TIAs. Diffusion-weighted imaging (DWI) provides evidence of acute cerebral ischemia in a third of TIA patients. We now report that DWI shows acute ischemia in 23% of patients clinically diagnosed as TNA by experienced stroke neurologists. This questions the accuracy of clinically diagnosing TIA and suggests added value for early magnetic resonance imaging after an episode of acute onset atypical or nonfocal neurological symptoms.

Cohort study ON Neuroimaging, Etiology and Cognitive consequences of Transient neurological attacks (CONNECT): study rationale and protocol.

BACKGROUND: Transient ischemic attacks (TIA) are characterized by acute onset focal neurological symptoms and complete recovery within 24 hours. Attacks of nonfocal symptoms not fulfilling the criteria for TIA but lacking a clear alternative diagnosis are called transient neurological attacks (TNA). Although TIA symptoms are transient in nature, cognitive complaints may persist. In particular, attacks consisting of both focal and nonfocal symptoms (mixed TNA) have been found to be associated with an increased risk of dementia. We aim to study the prevalence, etiology and risk factors of cognitive impairment after TIA or TNA. METHODS/DESIGN: CONNECT is a prospective cohort study on cognitive function after TIA and TNA. In total, 150 patients aged ≥45 years with a recent (<7 days after onset) TIA or TNA and no history of stroke or dementia will be included. We will classify events as: TIA, nonfocal TNA, or mixed TNA. Known short lasting paroxysmal neurological disorders like migraine aura, seizures and Ménière disease are excluded from the diagnosis of TNA. Patients will complete a comprehensive neuropsychological assessment and undergo MRI <7 days after the qualifying event and again after six months. The primary clinical outcomes will be cognitive function at baseline and six months after the primary event. Imaging outcomes include the prevalence and evolution of DWI lesions, white matter hyperintensities and lacunes, as well as resting state networks functionality and white matter microstructural integrity. Differences between types of event and DWI, as well as determinants of both clinical and imaging outcomes, will be assessed. DISCUSSION: CONNECT can provide insight in the prevalence, etiology and risk factors of cognitive impairment after TIA and TNA and thereby potentially identify a new group of patients at increased risk of cognitive impairment.

The reliability of magnetic resonance imaging in traumatic brain injury lesion detection.

OBJECTIVE: This study compares inter-rater-reliability, lesion detection and clinical relevance of T2-weighted imaging (T2WI), Fluid Attenuated Inversion Recovery (FLAIR), T2*-gradient recalled echo (T2*-GRE) and Susceptibility Weighted Imaging (SWI) in Traumatic Brain Injury (TBI). METHODS: Three raters retrospectively scored 56 TBI patients' MR images (12-76 years old, median TBI-MRI interval 7 weeks) on number, volume, location and intensity. Punctate lesions (diameter <10 mm) were scored separately from large lesions (diameter ≥ 10 mm). Injury severity was assessed with the Glasgow Coma Scale (GCS), outcome with the Glasgow Outcome Scale-Extended (GOSE). RESULTS: Inter-rater-reliability for lesion volume and punctate lesion count was good (ICC = 0.69-0.94) except for punctate lesion count on T2WI (ICC = 0.19) and FLAIR (ICC = 0.15). SWI showed the highest number of lesions (mean = 30.0), followed by T2*-GRE (mean = 15.4), FLAIR (mean = 3.1) and T2WI (mean = 2.2). Sequences did not differ in detected lesion volume. Punctate lesion count on T2*-GRE (r = -0.53) and SWI (r = -0.49) correlated with the GCS (p < 0.001). CONCLUSIONS: T2*-GRE and SWI are more sensitive than T2WI and FLAIR in detecting (haemorrhagic) traumatic punctate lesions. The correlation between number of punctate lesions on T2*-GRE/SWI and the GCS indicates that haemorrhagic lesions are clinically relevant. The considerable inter-rater-disagreement in this study advocates cautiousness in interpretation of punctate lesions using T2WI and FLAIR.

Subjective Cognitive Impairment, Depressive Symptoms, and Fatigue after a TIA or Transient Neurological Attack: A Prospective Study.

INTRODUCTION: Subjective cognitive impairment (SCI), depressive symptoms, and fatigue are common after stroke and are associated with reduced quality of life. We prospectively investigated their prevalence and course after a transient ischemic attack (TIA) or nonfocal transient neurological attack (TNA) and the association with diffusion-weighted imaging (DWI) lesions. METHODS: The Cognitive Failures Questionnaire, Hospital Anxiety and Depression Scale, and Subjective Fatigue subscale from the Checklist Individual Strength were used to assess subjective complaints shortly after TIA or TNA and six months later. With repeated measure analysis, the associations between DWI lesion presence or clinical diagnosis (TIA or TNA) and subjective complaints over time were determined. RESULTS: We included 103 patients (28 DWI positive). At baseline, SCI and fatigue were less severe in DWI positive than in DWI negative patients, whereas at follow-up, there were no differences. SCI (p = 0.02) and fatigue (p = 0.01) increased in severity only in DWI positive patients. There were no differences between TIA and TNA. CONCLUSIONS: Subjective complaints are highly prevalent in TIA and TNA patients. The short-term prognosis is not different between DWI-positive and DWI negative patients, but SCI and fatigue increase in severity within six months after the event when an initial DWI lesion is present.