Angiographic features, collaterals, and infarct topography of symptomatic occlusive radiation vasculopathy: a case-referent study.

BACKGROUND AND PURPOSE: Occlusive radiation vasculopathy (ORV) predisposes head-and-neck cancer survivors to ischemic strokes. METHODS: We analyzed the digital subtraction angiography acquired in 96 patients who had first-ever transient ischemic attack or ischemic strokes attributed to ORV. Another age-matched 115 patients who had no radiotherapy but symptomatic high-grade (>70%) carotid stenoses were enrolled as referent subjects. Digital subtraction angiography was performed within 2 months from stroke onset and delineated carotid and vertebrobasilar circulations from aortic arch up to intracranial branches. Two reviewers blinded to group assignment recorded all vascular lesions, collateral status, and infarct pattern. RESULTS: ORV patients had less atherosclerotic risk factors at presentation. In referent patients, high-grade stenoses were mostly focal at the proximal internal carotid artery. In contrast, high-grade ORV lesions diffusely involved the common carotid artery and internal carotid artery and were more frequently bilateral (54% versus 22%), tandem (23% versus 10%), associated with complete occlusion in one or both carotid arteries (30% versus 9%), vertebral artery (VA) steno-occlusions (28% versus 16%), and external carotid artery stenosis (19% versus 5%) (all P<0.05). With comparable rates of vascular anomaly, ORV patients showed more established collateral circulations through leptomeningeal arteries, anterior communicating artery, posterior communicating artery, suboccipital/costocervical artery, and retrograde flow in ophthalmic artery. In terms of infarct topography, the frequencies of cortical or subcortical watershed infarcts were similar in both groups. CONCLUSIONS: ORV angiographic features and corresponding collaterals are distinct from atherosclerotic patterns at initial stroke presentation. Clinical decompensation, despite more extensive collateralization, may precipitate stroke in ORV.

MRI of cardiac iron overload.

Transfusion therapy has greatly improved the survival of transfusion dependent thalassemia major (TM) patients; however, the resultant iron load damages tissues including the heart, liver and endocrine organs. Among these, heart complication still remains the leading cause of mortality. Myocardial iron deposition can occur independently of other solid organ involvement; conversely, the heart may be spared despite heavy siderosis in other tissues. Iron chelation treatment diminishes the risk of hemosiderosis; however, the chelation treatment has its own toxicities and might not be available to all patients due to costs. Close monitoring of individual organ iron concentration and function is thus important for optimization of individual patient care. This review outlines the importance and clinical significance of recently available MRI techniques for monitoring cardiac iron load.

Frequency and predictors of proxy-confirmed post-stroke cognitive complaints in lacunar stroke patients without major depression.

OBJECTIVE: Many lacunar stroke patients complained of cognitive decline after stroke. This study aims to investigate the factors underlying post-stroke cognitive complaints in these patients. METHODS: Seventy-five consecutive lacunar stroke patients without major depression were recruited for the study. Stroke severity was measured using NIHSS score and MRI was performed during the acute admission period. At 3 months, objective psychometric performance and depressive symptoms were assessed. Post-stroke cognitive complaints were corroborated by a proxy. Using logistic regression we examined the contribution of demographic features, stroke severity, objective psychometric scores, depressive symptoms, and imaging features (white matter lesion volume and infarct measures) to post-stroke cognitive complaints. RESULTS: Thirty-two (42.7%) patients had post-stroke cognitive complaints. Patients with post-stroke cognitive complaints had more depressive symptoms and worse psychometric performance than those without. In the multivariate logistic regression model, only the severity of depressive symptoms was independently associated with post-stroke cognitive complaints. CONCLUSIONS: This study suggests that post-stroke cognitive complaints are frequent among lacunar stroke patients without major depression and are prominently determined by the subclinical depressive symptomatology.

International reproducibility of single breathhold T2* MR for cardiac and liver iron assessment among five thalassemia centers.

PURPOSE: To examine the reproducibility of the single breathhold T2* technique from different scanners, after installation of standard methodology in five international centers. MATERIALS AND METHODS: Up to 10 patients from each center were scanned twice locally for local interstudy reproducibility of heart and liver T2*, and then flown to a central MR facility to be rescanned on a reference scanner for intercenter reproducibility. Interobserver reproducibility for all scans was also assessed. RESULTS: Of the 49 patients scanned, the intercenter reproducibility for T2* was 5.9% for the heart and 5.8% for the liver. Local interstudy reproducibility for T2* was 7.4% for the heart and 4.6% for the liver. Interobserver reproducibility for T2* was 5.4% for the heart and 4.4% for the liver. CONCLUSION: These data indicate that T2* MR may be developed into a widespread test for tissue siderosis providing that well-defined and approved imaging and analysis techniques are used.

Would self-expanding stent occlude middle cerebral artery perforators?

BACKGROUND AND PURPOSE: A major concern of intracranial stenting is perforator infarction. It is unclear whether the sustained radial force of a self-expanding stent or subsequent stent restenosis would cause late occlusion of perforators. METHODS: We compared the baseline and poststent (>or=4 months) MRI scans of patients who underwent self-expanding stenting for recurrent ischemic symptoms attributed to a MCA stenosis >or=60%. New infarcts in the ipsilateral striatocapsular region were recorded. RESULTS: MCA stenting was technically successful in 23 of 24 recruited patients. No new perforator territory infarct was found in follow-up MRI scans of all recruited patients. Postoperatively, all patients reported no further TIA or stroke over a median follow-up of 15 months. CONCLUSIONS: The use of a self-expanding stent in patients with high-grade MCA stenosis may not pose a major risk to the perforators.

Statins for asymptomatic middle cerebral artery stenosis: The Regression of Cerebral Artery Stenosis study.

BACKGROUND: The progression of cerebral atherosclerosis increases the risk of stroke and vascular events. Given the known benefits of statins in retarding coronary and carotid atherosclerosis progression, we studied the effects of statins on asymptomatic middle cerebral artery (MCA) stenosis progression. METHODS: We conducted a randomized, double-blind, placebo-controlled study to evaluate the effects of simvastatin on the progression of MCA stenosis among stroke-free individuals who had mild to moderately elevated LDL cholesterol (3.0-5.0 mmol/l). Two hundred and twenty-seven subjects were randomized to either placebo (n = 114) or simvastatin 20 mg daily (n = 113). The severity of MCA stenosis at baseline and at the end of the study was graded by MRA into normal, minimal (<10%), mild (10-49%), moderate (50-90%) and severe (>90%). The primary outcome was the change in grading of MCA stenosis over 2 years. RESULTS: At the end of the study, the LDL cholesterol level decreased by 1.43 and 0.12 mmol/l for the active and placebo groups, respectively (p < 0.001). There was no significant difference in the proportion of patients having stable, progressive and regressive MCA stenosis between the placebo (72, 22 and 6%) and active groups (78.6, 15.5 and 5.8%). The all-cause mortality was significantly lower in the active group (n = 0) relative to the placebo group (n = 7, p = 0.014). Any clinical events were also lower in the active group (n = 5) than in the placebo group (n = 13, p = 0.052). CONCLUSIONS: Simvastatin 20 mg daily had no apparent effect upon the evolution of asymptomatic MCA stenosis over 2 years.

The validity, reliability and clinical utility of the Hong Kong Montreal Cognitive Assessment (HK-MoCA) in patients with cerebral small vessel disease.

BACKGROUND/AIMS: To evaluate the psychometric properties of the Hong Kong Montreal Cognitive Assessment (HK-MoCA) in patients with cerebral small vessel disease (SVD). METHODS: 40 SVD patients and 40 matched controls were recruited. Concurrent and criterion validity, inter-rater and test-retest reliability, internal consistency of the HK-MoCA were examined and clinical observations were made. RESULTS: Performance on the HK-MoCA was significantly predicted by both executive (beta = 0.23, p = 0.013) and non-executive (beta = 0.64, p < 0.001) composite scores. It differentiated SVD patients from controls (area under the curve = 0.81, p < 0.001) with an optimal cutoff at 21/22. Reliability, internal consistency and clinical utility were good. CONCLUSION: The HK-MoCA is a useful cognitive screening instrument for use in SVD patients.

Emotional incontinence and executive function in ischemic stroke: a case-controlled study.

Frontal and basal ganglia infarcts and executive dysfunction are thought to be involved in the pathophysiology of poststroke emotional incontinence (PSEI). The study examined whether patients with PSEI have more frontal and/or basal ganglia infarcts and impairment in executive function. A total of 516 Chinese patients with acute ischemic stroke consecutively admitted to the acute stroke unit of a university-affiliated regional hospital in Hong Kong were screened for PSEI 3 months after the index stroke. According to Kim's criteria, 39 (7.6%) had PSEI. Thirty-nine stroke patients without PSEI served as matched control group. The PSEI group had significantly more frontal and/or basal ganglia infarcts, had lower Chinese Frontal Assessment Battery scores, required more time to complete the Stroop Test, and made more omission and commission errors in the Go-NoGo test. There was no significant correlation between frontal or basal ganglia infarcts and executive function. The correlation between frontal infarct and severity of PSEI was .420. Further follow-up and functional imaging studies are warranted to explore the relationship between PSEI, brain infarcts, and executive dysfunction. (JINS, 2009, 15, 62-68.).

Left ventricular systolic dyssynchrony is a predictor of cardiac remodeling after myocardial infarction.

OBJECTIVES: We sought to determine whether early assessment of left ventricular (LV) dyssynchrony by tissue Doppler imaging may predict progressive ventricular enlargement and cardiac dysfunction after acute myocardial infarction (MI). METHODS: Forty-seven patients (mean age 59.9 +/- 11.6 years) with normal QRS duration underwent tissue Doppler imaging and contrast-enhanced cardiac magnetic resonance imaging (Ce-MRI) at days 2 to 6, 3 months, and at 1 year after the index MI. Systolic dyssynchrony index (Ts-SD) was calculated from 12 LV segments, and infarct size (IS) by Ce-MRI. RESULTS: The remodeling group (n = 16) (defined as an increase in end-systolic volume > or =10% between 1 year and baseline) had greater initial IS (27.2 +/- 9.6 vs 13.7 +/- 4.1%, P < .001) and Ts-SD (50.9 +/- 12.8 vs 33.6 +/- 7.7 milliseconds, P < .001) than nonremodeling group (n = 31). At 1 year, the remodeling group had progressive increase in Ts-SD and decrease in LV ejection fraction (57.3 +/- 18.5 and 36.0 +/- 7.6%, respectively; both P < .05 vs baseline). Both Ts-SD (odds ratio 1.19 [1.07-1.32], P = .001) and IS (odds ratio 1.65 [1.19-2.29], P = .003) were shown to be independent predictors of progressive LV remodeling. A cutoff value of Ts-SD > or =45 milliseconds predicted LV remodeling at 1 year (sensitivity 90.5%, specificity 90.9%, Area-under-curve 0.907) (P = .0005). CONCLUSIONS: Left ventricular systolic dyssynchrony is a newly identified predictor of chronic LV remodeling after acute MI, which is independent and incremental to conventional assessment and IS as measured by Ce-MRI.

Risk vs benefit of anti-thrombotic therapy in ischaemic stroke patients with cerebral microbleeds.

BACKGROUND: Retrospective studies suggested that cerebral microbleeds (MB) on magnetic resonance images (MRI) increase risk of intracerebral haemorrhage (ICH). OBJECTIVE: To compare the benefit of anti-thrombotic agents in stroke prevention (absolute risk reduction 2.49 -6 %) versus risk of ICH in ischaemic stroke patients with MB. MATERIALS AND METHODS: We prospectively studied patients admitted consecutively for acute ischaemic stroke between 1999 and 2004. MB on MRI were documented. Primary end points were subsequent ICH, recurrent cerebral infarct (CI) and mortality. RESULTS: A total of 908 patients were recruited. MB were identified in 252 (27.8 %) patients. Mean follow-up period was 26.6 +/- 15.4 months. Risk of subsequent ICH increased significantly with quantity of MB: 0.6 % (no MB), 1.9 % (1 MB), 4.6 % (2-4 MB) and 7.6 % (>or= 5 MB) (p < 0.001). There was also a significant increase in mortality from ICH: 0.6 %, 0.9 %, 1.5 % and 3.8 % respectively (p = 0.054). Rate of recurrent CI was 9.6 %, 5.6 %, 21.5 % and 15.2 % respectively (p = 0.226). Mortality from CI and myocardial infarction did not increased with quantity of MB. Survival analyses showed that age, presence of MB, mixed cortical-subcortical distribution of MB were independent predictors of subsequent ICH. CONCLUSION: Risk and mortality of ICH increased with quantity of MB. As tendency to recurrent CI exceed that of ICH, anti-thrombotic agents are still warranted. However, in patients with >or= 5 MB, the high risk and mortality of ICH seem to outweigh the modest benefit of antithrombotic agents. Extra precautions should be taken to minimize risk of ICH. Further studies in patients on Coumadin and assessment of functional outcome are warranted to support these preliminary findings.

Clinical features, topographic patterns on DWI and etiology of thalamic infarcts.

Thalamic infarcts may lead to diverse neurological disturbances, which easily results in misdiagnosis. Diffusion-weighed magnetic resonance imaging (DWI) is sensitive for the early diagnosis of the infarct and identification of the territory involved. The aim of this study was to analyze the clinical features, topographic appearance on DWI and etiology of thalamic infarcts. We reviewed clinical data, vascular risk factors, topographic patterns and etiology of thalamic infarcts. The patients were divided into 2 groups according to DWI patterns: isolated thalamic infarcts (ISO-TH) and combined thalamic infarcts (COM-TH). The former were further subdivided into 2 subgroups: inferolateral isolated thalamic infarcts (INF-TH) and non-inferolateral isolated thalamic infarcts (NON-INF) according to the vascular territories. The Patients were also divided according to etiology based on TOAST classification. The association of clinical features, DWI patterns and etiology was analyzed. Twenty nine patients were included, among which, 23 (79.3%) were ISO-TH and 6 (20.7%) were COM-TH. The most common territory involved in the ISO-TH was inferolateral territory [n=17 (73.9%)], followed by tuberothalamic artery territory [n=3 (13.0%)], and posterior choroidal artery territory [n=2 (8.7%)]. In COM-TH, the most common territory also was the inferolateral territory (n=3), followed by posterior choroidal artery territory (n=1). In 2 patients, the lesions involved more than one vascular thalamic territory. Significant association between small-vessel occlusion (SVO) and ISO-TH (INF-TH+NON-IFN) infarcts were found. Our study suggested that SVO was more prevalent in ISO-TH, and COM-TH needed more etiological examination. DWI might provide meaningful clues about etiology of thalamic infarcts.

Middle cerebral artery stenosis increased the risk of vascular disease mortality among type 2 diabetic patients.

BACKGROUND: In Chinese populations, middle cerebral artery (MCA) stenosis is the most commonly identified intracranial vascular lesion, and has been shown to be associated with an increased risk of secondary stroke mortality, but has yet to be reported for primary events. We assess whether asymptomatic MCA stenosis is associated with mortality in Chinese type 2 diabetic patients. METHODS: The presence of MCA stenosis was determined by transcranial Doppler and mortality data were collated in the Hong Kong Death Registry. Cox proportional hazards regression was used to determine if the MCA stenosis (n = 272, 53.7% 2-vessel disease) in 2,197 diabetics was associated with all-cause or vascular disease mortality, including after adjustment for conventional vascular risk factors. Anthropometric and fasting biochemical parameters were compared between diabetic patients with MCA stenosis and without evidence of stenosis. RESULTS: A total of 191 deaths were identified (30.9% of vascular disease origin) during a follow-up of 18,279 patient years over 8.32 years. After adjustment for age, gender and diabetes duration, the hazard ratios for vascular mortality for 1- and 2-vessel disease were 2.47 (95% CI = 1.13-5.38) and 4.47 (95% CI = 2.24-8.82), p < 0.001 for trend, for increasing vascular mortality with increasing severity of cerebrovascular involvement, but 0.81 (95% CI = 0.45-1.47) and 2.23 (95% CI = 1.45-1.47), p = 0.001 for trend, for all-cause mortality. For vascular mortality, further adjustments for anthropometric and fasting biochemical parameters, or existing disease and treatment history increased the hazard ratios for 1-vessel disease slightly but attenuated the risk for 2-vessel disease evidently, 2.81 (95% CI = 1.10-7.16) and 2.85 (95% = CI 1.11-7.33), p = 0.026. CONCLUSION: The presence of MCA stenoses was an independent predictor of vascular mortality in these diabetics. More aggressive treatment of risk factors in these subjects merits further evaluation.

Neuroimaging predictors of cognitive impairment in confluent white matter lesion: volumetric analyses of 99 brain regions.

BACKGROUND: Although confluent white matter lesion (WML) is associated with cognitive impairment, the mechanism explaining this association is controversial. We aimed to investigate comprehensively the MRI predictors of cognitive impairment in confluent WML. METHODS: Among 45 lacunar stroke patients who had confluent WML, we evaluated the association of executive function [Mattis Dementia Rating Scale - Initiation/Perseveration subscale (MDRS I/P)] and global cognition [Mini-Mental State Examination (MMSE)] with the volume of WML, measures of lacunes and microbleeds, and the volumes of 99 other specific brain regions. RESULTS: Regression analyses showed that WML volume predicted performance on the MDRS I/P (beta = -0.34, p = 0.016) independent of age. Volumes of cortical gray matter (cGM; beta = 0.41, p = 0.003), the lateral fronto-orbital gyrus (beta = 0.38, p = 0.01), superior frontal gyrus (beta = 0.29, p = 0.04), lateral ventricle (beta = -0.30, p = 0.04), and posterior limb of the internal capsule (beta = 0.43, p = 0.002) predicted MDRS I/P performance independent of WML volume. Volumes of cGM, and the lateral fronto-orbital gyrus predicted MMSE performance as well. CONCLUSION: Atrophy along the frontosubcortical pathways and cGM predict cognition in confluent WML independent of WML volume.

Multimodal computed tomography evaluation before thrombolysis in acute ischaemic stroke.

Currently, when stroke patients are offered thrombolytic therapy, their ischaemic stroke subtypes are usually unknown. Given the risk of haemorrhage that accompanies thrombolytic therapy, unselective (or undiscriminating) use of recombinant tissue plasminogen activator in patients without large-artery thromboemboli is potentially hazardous. Advances in computed tomography techniques have enabled the stroke pathophysiology to be quickly delineated by multimodal computed tomography without compromise in time for recombinant tissue plasminogen activator administration. Through description of the investigation of a typical stroke patient, we report how this technique is feasible in a regional hospital and may guide judicious use of recombinant tissue plasminogen activator.

Total cerebral blood flow estimated by color velocity imaging quantification ultrasound: a predictor for recurrent stroke?

Although the Virchow's triad on thrombosis includes reduced blood flow as a factor, there has been relatively little data on the importance of total cerebral blood flow on the risk of subsequent stroke. In the current study, we investigate whether total cerebral blood flow helps predict stroke recurrence. Extracranial arterial blood flow volume estimated by color velocity imaging quantification ultrasound (CVIQ) is an index of cerebral blood flow measurement. We performed a cohort study of 210 consecutive acute stroke patients. Patients were studied with transcranial Doppler and duplex ultrasound for intra- and extracranial large artery disease within 3 days of symptom onset. The association between the risk of recurrent stroke and CVIQ was analyzed with Cox proportional hazards model. Thirty-nine patients (17.7%) developed an ischemic stroke during a mean follow-up of 47.5 months. The mean extracranial blood flow volume was significantly lower for patients who had a recurrent stroke than those without (594.4+/-130.3 versus 683.8+/-176.9 mL/min; P=0.003). In a Cox proportional hazards model adjusting for potential confounding variables, extracranial blood flow volume (hazard ratio (HR) for lowest tertile, 4.1; 95% confidence interval (CI), 1.5 to 11.0) along with male sex (HR, 2.5; 95% CI, 1.3 to 5.1), diabetes (HR, 2.5; 95% CI, 1.2 to 5.0) and large artery stenosis (HR, 2.2; 95% CI, 1.1 to 4.4) were independent predictors for stroke recurrence. Our data indicated that patient with low amount of blood flow to the brain is at risk of recurrent stroke.

Strain rate imaging differentiates transmural from non-transmural myocardial infarction: a validation study using delayed-enhancement magnetic resonance imaging.

OBJECTIVES: The aim of this study was to determine if strain rate imaging (SRI) correlates with the transmural extent of myocardial infarction (MI) measured by contrast-enhanced magnetic resonance imaging (Ce-MRI). BACKGROUND: Identification of the transmural extent of myocardial necrosis and degree of non-viability after acute MI is clinically important. METHODS: Tissue Doppler echocardiography with SRI and Ce-MRI were performed in 47 consecutive patients with a first acute MI between days 2 and 6 and compared to 60 age-matched healthy volunteers. Peak myocardial velocities and peak myocardial deformation strain rates were measured. Location and size of the infarct zone was confirmed by Ce-MRI using the delayed enhancement technique with a 16-segment model. RESULTS: Contrast-enhanced MRI identified transmural infarction in 21 patients, non-transmural infarction in 15 (mean transmurality of infarct 72.3 +/- 10.6%), and another 11 patients with subendocardial infarction (<50% transmural extent of the left ventricular wall). Peak systolic strain rate (SRs) of the transmural infarction segments was significantly lower compared to normal myocardium or with non-transmural infarction segments (both p < 0.0005). A cutoff value of SRs >-0.59 s(-1) detected a transmural infarction with high sensitivity (90.9%) and high specificity (96.4%), and -0.98 s(-1) >SRs >-1.26 s(-1) distinguished subendocardial infarction from normal myocardium with a sensitivity of 81.3% and a specificity of 83.3%. CONCLUSIONS: Peak myocardial deformation by SRI can differentiate transmural from non-transmural MI, and it allows noninvasive determination of transmurality of the scar after MI and thereby the extent of non-viable myocardium.

Hyperhomocysteinemia is associated with volumetric white matter change in patients with small vessel disease.

BACKGROUND: Hyperhomocysteinemia is associated with cerebral small vessel disease (SVD). We examined the relationship between homocysteine and 1) volumetric measure of white matter change (WMC), 2) silent brain infarcts, 3) cerebral atrophy on MRI and 4) cognition on a consecutive cohort of patients with stroke associated with SVD. SUBJECTS AND METHODS: Fifty-seven patients consecutively admitted to the Acute Stroke Unit in a university hospital due to stroke associated with SVD were recruited and assessed three months after the stroke. Non-fasting homocysteine was obtained. Using MRI, the number of infarcts, volume of WMC and cerebral atrophy were measured. General cognitive functions were assessed using the Mini Mental State Examination and Alzheimer's disease Assessment Scale. Mattis Dementia Rating Scale - Initiation/Perseveration subset was used to assess executive cognitive functions. RESULTS: Hyperhomocysteinemia (> or = 14.88 micromol/L) significantly accounted for the volume of WMC on MRI in a multivariate stepwise regression model (adjusted R(2)=0.058, p <0.05) after adjustment for age and folate level. Patients in the highest quartile of WMC volume had significantly higher levels of homocysteine than those in lowest quartile (p <0.001). No significant relationship was found between homocysteine and silent brain infarcts, cerebral atrophy and performance on psychometric tests. CONCLUSION: Hyperhomocysteinemia is associated with volumetric measure of WMC among patients with SVD. The role of homocysteine in the development of silent brain infarcts and cerebral atrophy as previously reported cannot be ascertained in this study. No direct relationship was found between homocysteine and cognitive functions.

Thin-Section CT 12 Months After the Diagnosis of Severe Acute Respiratory Syndrome in Pediatric Patients.

OBJECTIVE: The objective of our study was to report the thin-section CT findings 12 months after the diagnosis of severe acute respiratory syndrome (SARS) in pediatric patients who had recovered clinically but had persistent abnormal CT findings 6 months after the diagnosis. The clinical data for these patients were correlated to identify risk factors that might increase the likelihood of the development of CT abnormalities. SUBJECTS AND METHODS: The study involved an extended 12-month thin-section CT follow-up of 16 of 47 pediatrics patients with SARS coronavirus-associated pneumonia proven serologically (21 girls and 26 boys; age range, 1.5-17 years; median age, 13.6 years). Patients' clinical information, the extent of radiographic opacification during the acute phase of illness, and conventional pulmonary function test results on follow-up were obtained for correlation. The clinical parameters were compared with other pediatric SARS patients who had normal CT findings at the 6-month follow-up. RESULTS: Fifteen patients still had abnormal CT findings 12 months after diagnosis, all of whom were older than 10 years (age range, 10-17 years). In seven patients with previous residual ground-glass opacification at the 6-month follow-up, two showed persistent changes and three had a reticular pattern in the area of the previously detected abnormality, whereas two showed complete resolution. The extent of air trapping remained similar to that at the 6-month follow-up in nine of 11 patients while two showed a slight increase in the same segments. Parenchymal scars remained unchanged from the 6- to 12-month follow-up in all six patients with that finding. None of our patients showed any evidence of bronchiectasis or bronchial wall thickening. Lymphopenia (p = 0.03), extent of radiographic opacification at acute illness (p = 0.047), and duration of use of ribavirin (p = 0.03) were significant risk factors in predicting whether abnormal CT features persisted 12 months after diagnosis. CONCLUSION: We found that 32% of the children (15/47) affected with SARS showed thin-section CT abnormalities up to 12 months after diagnosis despite clinical remission and unremarkable pulmonary function assessment. Persistent CT abnormalities are more likely to develop in patients who are older and who present with more severe disease. The CT changes in children with SARS are, however, minor.

Topographic patterns of small subcortical infarcts associated with MCA stenosis: a diffusion-weighted MRI study.

BACKGROUND AND PURPOSE: Small subcortical infarcts (SSI, maximum lesion diameter < or =2.0 cm) are usually considered as infarcts caused by small vessel disease. However, SSI can also be associated with large artery occlusive disease such as middle cerebral artery (MCA) stenosis. We performed a prospective study to investigate the relationship between MCA stenosis and SSI distribution and further to investigate the mechanism of SSI caused by MCA stenosis. METHODS: Magnetic resonance angiography (MRA) and diffusion-weighed MRI (DWI) of consecutive acute ischemic stroke patients with recent SSI were studied. The distribution of acute infarcts on DWI was categorized as cortical infarct (CI), border zone infarct (BI), or perforating artery infarct (PAI). RESULTS: Totally, 93 cases were recruited, among which 12 had single SSI with MCA stenosis (group 1) and 26 patients had multiple SSI with MCA stenosis (group 2), while 55 patients without MCA stenosis had single SSI (group 3). For patients with single SSI and MCA stenosis, 6 had BI and 6 had PAI; for patients with multiple SSI and MCA stenosis, 25 had BI, 4 had PAI and 9 had CI (compared with group 1: P= .001); for patients with single SSI but without MCA stenosis, 20 had BI and 35 had PAI (compared with group 1: P= .58). CONCLUSION: Multiple acute infarcts along the border zone are the commonest pattern in small infarcts with MCA stenosis, especially among those with multiple acute infarcts. Our data suggest that hemodynamic compromise and artery-to-artery embolism may be both important factors for infarcts in patients with MCA stenosis.

Changes in vertebral neural arch morphometry and functional tethering of spinal cord in adolescent idiopathic scoliosis--study with multi-planar reformat magnetic resonance imaging.

With the use of multiplanar reformat Magnetic Resonance imaging, AIS patients were found to have significantly reduced pedicle widths on concavity. Pattern of vertebral asymmetry was also exaggerated with smaller pedicle width, length and area on concavity. The cord appeared more roundish and was deviated to the concavity at apical vertebra in AIS. A tethering force might therefore be present on the cord along the transverse axis in AIS, accounted by the relatively fixed position of the exit nerve roots and deviation of the cord from the exit foraminae of the corresponding vertebra.