Effectiveness of Nonvitamin K Antagonist Oral Anticoagulants and Warfarin for Preventing Further Cerebral Microbleeds in Acute Ischemic Stroke Patients with Nonvalvular Atrial Fibrillation and At Least One Microbleed: CMB-NOW Multisite Pilot Trial.

BACKGROUND: Nonvitamin K antagonist oral anticoagulants (NOACs) are considered superior, or at least noninferior, to warfarin in preventing stroke or systemic embolism in patients with nonvalvular atrial fibrillation. Here, we recruited acute ischemic stroke patients with nonvalvular atrial fibrillation and at least one cerebral microbleed (CMB), and evaluated the proportion of patients who had an increased number of CMBs (%) after receiving anticoagulant therapy with NOACs or with warfarin for 12 months. METHODS: This was a multicenter, prospective, observational cohort study at 20 centers, conducted between 2015 and 2017, in which we recruited 85 patients with at least one CMB detected by 1.5T magnetic resonance imaging (T2*WI) at baseline, who received NOACs or warfarin for at least 12 months. We compared the proportions of patients with increased numbers of CMBs in the NOACs and warfarin treatment groups. RESULTS: The proportions of patients with increased numbers of CMBs at month 12 of treatment were 28.6% and 66.7% in the NOACs and warfarin groups, respectively. The new CMBs showed no specific regional localization in either group. In the NOACs and warfarin groups, physicians prescribed lower-than-standard dosing in 13.3% and 50% of the cases, respectively. The administration of reduced doses at physicians' discretion did not appear to alter the incidence of new CMBs. DISCUSSION: This is the first evidence to suggest efficacy of NOACs for preventing further CMBs in patients with at least one CMB, although no statistical evaluation was carried out.

Common and specific risk factors for ischemic stroke in elderly: Differences based on type of ischemic stroke and aging.

BACKGROUND: The risk factors among the types of ischemic stroke (atherothrombotic cerebral infarction: ATI, cardio-embolic infarction: CEI, lacunar infarction: LI) in aged stroke patients have rarely been compared to each other. METHODS: We compared the clinical parameters of 300 elderly patients with ischemic stroke, age 65-98years, to 100 age-matched control patients. RESULTS: Comparison by parametric test and logistic regression analysis between all 300 and 100 control patients showed higher systolic and diastolic blood pressures (p<0.001, p=0.03), lower estimated glomerular filtration rate (eGFR) (p=0.01), larger cardiothoracic ratio (CTR) (p<0.001), smoking (p<0.01) and possibly poor adherence to anti-hypertensive agents in the ischemic stroke patients (p<0.001). Comparisons among three types (n=100 for each) showed the highest atheromatous risk factors for ATI to be hemoglobin A1c (p=0.01) and low-density lipoprotein (p<0.001) and for CEI to be largest cardiac load, indicated by largest left atrial dimension (p<0.001), and CTR (p<0.001). Triglyceride level was found to be a borderline risk factor for LI (p=0.054). Comparison between those aged <74 versus ≥75years (n=150 for each) showed a lower eGFR (p=0.02) and larger right atrial dimension (p<0.001) in patients ≥75. CONCLUSION: The risk factors were quite different among the subtypes and aging.

Improved image quality of helical computed tomography of the head in children by iterative reconstruction.

BACKGROUND AND PURPOSE: Iterative reconstruction (IR) offers noise reduction and improved image quality of computed tomography (CT). Our aim was to assess the imaging quality of non-contrast helical CT of the head in children using IR. MATERIALS AND METHODS: This study recruited 78 consecutive children aged ≤5 years (range: from 3 months to 5 years; mean: 1.7 years) who underwent an emergent non-enhanced helical CT of the head with no abnormal findings. The acquired data were reconstructed using filtered back projection (FBP) and sinogram-affirmed IR (SAFIRE) with strength levels of 2 (IR2) and 4 (IR4). The imaging quality of FBP, IR2 and IR4 was scored by two experienced neuroradiologists in terms of the contrast between the gray-white matter junction and artifacts from the skull at the level of the semioval center, basal ganglia and fourth ventricle. FBP, IR2 and IR4 scores were compared at each slice level. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated for FBP, IR2 and IR4 and were compared among the three reconstruction algorithms. RESULTS: The score of IR2 and IR4 was significantly higher than that of FBP in terms of both the contrast between the gray-white matter junction and artifacts from the skull at each slice level (P<0.001). SNR and CNR on IR4 were the highest followed by those on IR2 and FBP (P<0.001). CONCLUSIONS: IR may improve the image quality of helical CT of the head in children.

Severity of white matter hyperintensities in older adults aged in their mid 80s and its relationship with hemodynamic and cardiac parameters.

AIM: In the present study, we analyzed the severity of white matter hyperintensities detected on magnetic resonance imaging of the brain in older Japanese adults who were aged in their mid 80s, and examined its relationships with the clinical parameters. METHODS: To identify factors related to the severity of white matter hyperintensities in 33 older adult attendees of our outpatient clinic and 17 older adults living in a group home, we carried out logistic regression analyses and/or correlation analyses. RESULTS: Cognitive function and activities of daily living were significantly correlated with the severity of white matter hyperintensities. Multivariate analysis identified activities of daily living, but not cognitive function, as being independently associated with the severity of white matter hyperintensities. Several hemodynamic and cardiac parameters, including diastolic blood pressure, hemoglobin, serum level of N-terminal pro-brain natriuretic peptide, cardiothoracic ratio on the chest X-ray, severity of supraventricular arrhythmias on a Holter electrocardiogram and serum levels of docosahexaenoic acid, were significantly correlated with the severity of white matter hyperintensities. In contrast, the serum cholesterol, glycosylated hemoglobin value and systolic blood pressure were not correlated with the severity of white matter hyperintensities. CONCLUSIONS: The severity of white matter hyperintensities detected on magnetic resonance imaging of the brain in older Japanese patients aged in their mid 80s was significantly correlated with activities of daily living, hemodynamic and cardiac parameters, and the serum level of docosahexaenoic acid.

Protocol for Cerebral Microbleeds during the Non-Vitamin K Antagonist Oral Anticoagulants or Warfarin Therapy in Stroke Patients with Nonvalvular Atrial Fibrillation (CMB-NOW) Study: Multisite Pilot Trial.

RATIONALE: Anticoagulants are widely used to prevent recurrence of ischemic stroke in patients with nonvalvular atrial fibrillation, but in some patients, they also cause bleeding, particularly intracranial hemorrhage. One of the independent predictors of intracerebral hemorrhage is the presence of cerebral microbleeds (CMBs); a high incidence of intracerebral hemorrhage is reported in warfarin-treated patients with multiple CMBs. Longitudinal study suggested that the presence of CMBs at baseline is a predictor of new CMBs in warfarin-treated patients. However, there has been no study on the progression of CMBs in patients receiving the non-vitamin K antagonist oral anticoagulants (NOACs). AIMS: This study tests the hypothesis that the incidence of hemorrhagic stroke is lower in patients receiving NOACs (dabigatran, rivaroxaban, apixaban, and edoxaban) than in those receiving warfarin, and this difference reflects the difference in the effects of warfarin and NOACs on the progression of CMBs. DESIGN: We will enroll 200 patients with at least 1 CMB detected by 1.5 T magnetic resonance imaging (T2(∗)-weighted imaging) at baseline and who have received NOACs or warfarin for at least 12 months. Primary end point is the proportion of subjects with an increased number of CMBs at month 12 of treatment with NOACs or warfarin. If the results of this study support the efficacy of NOACs for preventing increase of CMBs, this would be of great interest to domestic and overseas clinicians, in view of the potential therapeutic impact, including that on primary prevention of ischemic stroke.

Dynamic cross-sectional changes of the middle cerebral artery in atherosclerotic stenosis detected by 3·0-Tesla MRI.

OBJECTIVES: Atherosclerotic stenosis of the middle cerebral artery (MCA) is one of the causes of ischemic stroke, but aside from investigations using magnetic resonance angiography (MRA), studies evaluating stenosis are rare. The purpose of this study was to assess dynamic changes of MCA cross section between the systolic and diastolic phases in patients with cerebral infarction using 3·0-Tesla magnetic resonance imaging (3T MRI). METHODS: We assessed 12 stroke patients with M1 stenosis in the MCA and 12 healthy volunteers. We measured MCA cross sections (proximal/distal to stenosis and on the stenosis) in the systolic and diastolic phases by synchronizing imaging with heartbeats, as well as the maximum flow velocity by using cine-phase contrast (PC) MRI. Each patient also underwent conventional MRA. RESULTS: Differences in cross sections between systolic and diastolic phases were significantly smaller in the stenosed artery compared to the distal (P < 0·05) and proximal areas (P < 0·01) in stroke patients. The difference in maximal blood velocity between systolic and diastolic phases at the M1 stenosis was significantly larger than that in the area proximal to the stenosis (P < 0·05). DISCUSSION: We clearly demonstrated dynamic cross-sectional changes in the stenotic areas by 3T MRI, suggesting hemodynamic shear stress, which may further enhance MCA atherosclerosis.

Predictors for hemorrhagic transformation with intravenous tissue plasminogen activator in acute ischemic stroke.

We examined the predictive value of clinical and radiological findings, including cerebral microbleeds (CMBs) seen in gradient-echo T2*-weighted magnetic resonance images, for hemorrhagic transformation (HT) following ischemic stroke, in ischemic stroke patients treated with recombinant tissue plasminogen activator (rt-PA). The subjects were 71 patients with acute ischemic stroke treated with rt-PA (50 males, 21 females; mean age±standard deviation 73±10 years; 53 cardiogenic stroke, 18 atherothrombotic). HT on computed tomography (CT)(mean: 24 hours after onset) was seen in 26 (37%) subjects. The mean Alberta stroke programme early CT score on diffusion-weighted images (ASPECTS-DWI) score was significantly lower in the group with HT than that in the group without HT (6.5±2.3 vs 8.4±1.6, P<0.001). Prevalence of CMBs was not significantly different between the groups with and without HT. Relative risk of various factors for appearance of HT was evaluated by logistic regression analysis. Increased ASPECTS-DWI score showed a significantly reduced relative risk for HT (odds ratio: 0.54, 95% confidence interval: 0.33-0.87), while the influence of CMBs (1.22, 0.23-6.53) was not significant. In conclusion, ASPECTS-DWI score (a measure of the volume of ischemic tissue) is a useful marker for predicting HT. On the other hand, CMBs on T2*-weighted images may not be predictive for HT in patients treated with intravenous rt-PA.

High incidence of radiation-induced cavernous hemangioma in long-term survivors who underwent hematopoietic stem cell transplantation with radiation therapy during childhood or adolescence.

Radiation-induced cavernous hemangioma (RICH) is a late complication of cerebral radiation therapy. Long-term survivors of hematopoietic stem cell transplantation (HSCT) who underwent radiation therapy could be at increased risk for RICH. We investigated records of 68 patients who underwent HSCT during childhood or adolescence and were assessed by magnetic resonance imaging (MRI), including T2*-weighted imaging of the brain, annually for 5 years over a range of 6 to 29 years after HSCT. We developed a scoring and grading system for RICH to monitor the process and the progress of radiologic changes. Among the 68 patients investigated, 28 (41.2%) were diagnosed with CH. All 28 patients had received total body irradiation as a conditioning treatment for HSCT and/or cranial radiation therapy before HSCT as part of the treatment of their primary disease. RICH was diagnosed in none of the patients who did not receive radiation (n = 19), in 46.2% of those who received 6 to 12 Gy (n = 39), and in all of those who received 18 to 36 Gy (n = 10). Total RICH scores were correlated with higher radiation doses. Careful and long-term evaluation with MRI, including T2*-weighted imaging, is necessary for HSCT recipients who received radiation therapy before and/or during HSCT.

The middle meningial artery during a migraine attack: 3T magnetic resonance angiography study.

We performed 3T magnetic resonance angiography (MRA) during a spontaneous migraine attack. The patient was a 42-year-old woman migraineur diagnosed by the IHS criteria. The change of the middle meningial artery (MMA) was measured on the axial brain images using MATLAB for three phases (attack-free period, during an attack, a period after medication). There were no dramatic changes of vasodilation in the MMA during the attack (2.0 mm), attack-free period (diameter 1.9 mm), or period after medication (1.7 mm), resembling extrapolations of observations in experimental animal models. This finding suggests that the dramatic vasomotion might not be associated with migraine pathophysiology.

Three-dimensional CT and histopathological findings of airway malacia in Hunter syndrome.

A 19-year-old man with known Hunter syndrome presented with dyspnea, and was admitted to our hospital. Bronchoscopy revealed tracheal narrowing with excessive granulation tissue formation in the trachea. Three-dimensional CT clearly demonstrated severe stenosis in the trachea and both main bronchi. Autopsy showed granulomatous tissue proliferation and deposition of mucopolysaccharide in the tracheal wall. We demonstrated the clinico-radiological-pathological correlation of bronchial lesions in Hunter syndrome, and emphasized that three-dimensional CT is helpful in deciding upon therapeutic strategy to treat stenosis in the large airway.

A case of pulmonary semi-invasive aspergillosis developing fatal acute exacerbation.

A 80-year-old male was referred for detailed examination of left apical fibrotic changes in the chest radiograph. Six years later, several cavitary lesions with thickening of the pleura developed. Anti tuberculosis therapy had no effects. Despite intravenous administration of antibiotics, the cavities became larger and the infiltrates progressed to the left lower lobe. The air crescent was observed in one of the cavities. Repeated sputum examinations revealed Aspergillus niger only. With administration of anti fungal drug, infiltrates were faded. Four months after the cessation of antifungal drug high fever associated with new infiltrates developed. Sputum culture showed Aspergillus flavus. Infiltrates over the entire left lung field and in the right upper lobe were observed. On CT film necrotic lung tissue was strongly suggested in the cavity. The patients died of respiratory failure. Although initial course of the presented case was compatible with semi-invasive pulmonary aspergillosis (SIPA), fluminant and fatal exacerbations which may be very unusual in SIPA, developed in later. The mycetoma-like ball may be occasionally made of necrotic lung parenchyma instead of fungal mycelia in SIPA.

[Continuous speech recognition system for radiological reporting: comparison with experience of dictation].

PURPOSE: To compare rates of accuracy of recognition between experienced dictators and inexperienced ones in using an enrollment-less continuous speech recognition (CSR) system of radiological reporting, and to evaluate the usefulness of the system. MATERIALS AND METHODS: Twenty board-certified radiologists were classified into 2 groups: a group of 10 members with more than 6 years' experience of conventional dictation by transcriptionist (group A) and a group of 10 members with no experience of dictation (group B). All radiologists created fresh radiological reports on sets of images using free-style dictation in the reports. We counted errors and total words in the reports individually, and compared the rates of accuracy of word recognition in the two groups. We used a CSR system AmiVoice (Advanced Media, Inc., Tokyo, Japan). RESULTS: The average rate of accuracy of word recognition was 96.42 +/- 1.68% in group A and 95.92 +/- 1.15% in group B. There was no significant difference in accuracy rate between the two groups. CONCLUSION: The accuracy of word recognition was independent of the experience of dictation, and the enrollment-less CSR system of radiological reporting was considered convenient and useful.

An analysis of the chest wall motions using the dynamic MRI in healthy elder subjects.

The objective of this study was to compare respiratory motions of the chest wall in the healthy elder subjects (N = 5; mean age, 71 years old) with those in healthy young subjects (n = 9; mean age, 29 years old). Thirty sequential images (scanning time, 0.4s per image) of dynamic MRI on sagittal and coronal planes were obtained while the subjects were deeply breathing. Lung volume change was simultaneously measured with pneumotachometer. In the elder subjects, dimensions of the middle and posterior parts of the diaphragm were linearly related to instantaneous lung volume. There were poor correlation between motion of the anterior diaphragm and transverse motions of the upper rib-cage and lower rib-cage. The contribution of individual part of the chest wall motion to a unit lung volume change, assessed by slope of the linear regression line, in elder subjects were not significantly different from those in young subjects. Either in the elder or young subjects, the middle and posterior parts of the diaphragm moved coordinately. We conclude that chest wall motion in the healthy elder subjects is not different from that in healthy young people and that middle and posterior parts of the diaphragm act as one functional unit during deep breathing.