Does diving damage the brain? MR control study of divers' central nervous system

Purpose:
To evaluate the prevalence of cerebral white matter changes on MR imaging in healthy elderly compressed air divers with a long diving history in comparison with control subjects who have never dived.
Material and Methods:
The investigation employed 59 experienced elderly divers and 48 control subjects matched for age, body mass index, alcohol and smoking history. MR studies included a fluid attenuated inversion recovery sequence and T1- and T2-weighted pre- and postcontrast images in axial orientation of the whole brain to localize white matter changes.
Results:
MR images did not show any morphologic abnormalities in the brains of divers. Both groups - divers and controls - did not differ significantly with respect to white matter changes of the brain.
Conclusion:
No increased prevalence of cerebral white matter changes in compressed air divers compared with a healthy worker sample of similar age were found. Thus, extensive compressed air diving may not necessarily be related to radiological changes on MR.     

Echo-planar MR imaging of human brain oxygenation changes

Echo-planar magnetic resonance (MR) imaging was used to observe signal intensity changes in the human brain during hypoxia. Increasing arterial blood levels of deoxyhemoglobin (0%–42%) during prolonged apnea were monitored with a pulse oximeter and correlated with gray matter and white matter signal attenuation of 13% and 20%, respectively. The results suggest the possibility of using deoxyhemoglobin boluses as a physiologic, intravascular susceptibility contrast agent for assessment of local cerebral oxygen utilization.     

Quantitative MR imaging of children with sickle cell disease: Striking T1 elevation in the thalamus

Nineteen patients with sickle cell disease (SCD) were examined with conventional MR imaging (cMRI), including T1- and T2-weighted sequences and MR angiography (MRA). qMRI mapping of T1 was also done using a precise and accurate inversion-recovery (PAIR) technique optimized and validated previously. In addition, 21 healthy African-American control subjects had the qMRI examination. Nonparametric Kruskal-Wallis analysis of variance of control subjects, of SCD patients without stroke, and of SCD patients with stroke showed that T1 increased with disease severity in the thalamus, frontal white matter, genu, and occipital white matter. T1 was significantly longer in SCD patients without stroke (n=13) than in control subjects (n=21) in the thalamus and frontal white matter. In addition, T1 values were significantly longer in SCD patients with stroke than in patients without stroke in the genu and frontal white matter. Abnormality of the thalamus was identified by qMRI in a substantial fraction of patients read as normal by both cMRI and MRA, suggesting that it may be possible to use T1 elevation to identify a subset of patients with SCD who are at elevated risk for stroke.     

2个CADASIL患者的弥散张量成像与20例正常人的比较

目的　分析2例CADASIL患者的MR特点及弥散张量指标的变化。方法　收集2例通过病理和基因检查确诊为CA DASIL的先证者的临床资料,对其进行常规MR扫描和弥散张量成像,将弥散张量成像的指标与20例正常志愿者的指标进行比较。结果　2例CADASIL患者的MR主要表现为双侧额顶叶白质内多发腔梗、脱髓鞘改变和双侧颞叶前部白质脱髓鞘。1例患者双侧外囊、内囊后肢、胼胝体膝部和压部的部分各向异性(FA)值均小于正常组的平均值减去2倍标准差,另1例患者左侧外囊的FA值小于对照组的平均值减去2倍标准差。结论　常规MR表现和弥散张量成像指标的测量均反映了CADASIL患者中存在严重的白质病变。     

Brain MRI Findings of Carbon Disulfide Poisoning

Objective

To evaluate the findings of brain MRI in patients with carbon disulfide poisoning.

Materials and Methods

Ninety-one patients who had suffered carbon disulfide poisoning [male:female=87:4; age, 32-74 (mean 53.3) years] were included in this study. To determine the extent of white matter hyperintensity (Grade 0-V) and lacunar infarction, T2-weighted MR imaging of the brain was performed.

Results

T2-weighted images depicted white matter hyperintensity in 70 patients (76.9%) and lacunar infarcts in 27 (29.7%).

Conclusion

In these patients, the prevalent findings at T2-weighted MR imaging of the brain were white matter hyperintensity and lacunar infarcts. Disturbance of the cardiovascular system by carbon disulfide might account for these results.     

Demographics and respiratory illness prevalence of sport scuba divers

This study aimed to establish epidemiological data on diving habits and outcome of subjects with respiratory diseases who are considered at increased risk for diving injuries. We conducted a cross-sectional demographics and prevalence study by distribution of an anonymous questionnaire with an issue of a widespread sport diving magazine. The questionnaire was designed to obtain medical and diving history data with an emphasis on respiratory diseases and complaints. The investigational population comprised sport scuba divers of any age and gender from Austria, Germany, and Switzerland. Two hundred and twenty-six male and 96 female divers sent completed questionnaires. Of the respondents 8.7 % indicated that they currently have asthma. Two thirds of asthmatics complained about regular dyspnoea. However, only 42.4 % used drugs relieving or controlling their symptoms regularly and 27.3 % used them in a prophylactic manner before diving. Five percent and 4.7 % of all divers reported a history of respiratory disease other than asthma or dyspnoea respectively. The divers with respiratory illness or complaints had logged a total of 17,386 dives. There were no cases of serious diving injuries. Despite the well-known limitations of postal surveys assessing self reported data, this study indicates that there is a population of subjects diving uneventfully with respiratory diseases that are considered medical contraindications to diving. These subjects deserve particular guidance on related risks and disease management.     

Prevalence of temporomandibular dysfunction in a group of scuba divers

BACKGROUND: Temporomandibular dysfunction (TMD) has been reported to be a common problem in divers, with a prevalence of up to 68%. No evidence for this is available. OBJECTIVE: To investigate the prevalence of TMD in divers. METHOD: Sixty three subjects were asked to retrospectively complete a questionnaire on symptoms of TMD after diving in warm and cold water areas and in daily life. RESULTS: The prevalence of TMD was greater in female divers. The prevalence of TMD while diving was about 26%, comparable to that experienced in daily life. CONCLUSION: Improvements in mouthpiece design and lighter demand valves mean that TMD is now probably exacerbated by diving rather than caused by it.     

Glucocorticoid treatment of brain tumor patients: changes of apparent diffusion coefficient values measured by MR diffusion imaging

Glucocorticoids (GCC) generally are administered to patients with brain tumors to relieve neurological symptoms by decreasing the water content in a peritumoral zone of edema. We hypothesized that diffusion imaging and apparent diffusion coefficient (ADC) values could detect subtle changes of water content in brain tumors and in peritumoral edema after GCC therapy. The study consisted of 13 patients with intra-axial brain tumor, and ADC was measured in the tumor, within peritumoral edema, and in normal white matter remote from the tumor before and after GCC therapy. ADC also was measured in normal white matter in four control patients with no intracranial disease who were treated with GCC for other indications. Conventional MR images showed no visually evident interval change in tumor size or the extent of peritumoral edema in any subject after GCC therapy, which nonetheless resulted in a decrease in mean ADC of 7.0% in tumors (P<0.05), 1.8% in peritumoral edema (P>0.05, not significant) and 5.8% in normal white matter (P<0.05). In patients with no intracranial disease, GCC therapy decreased mean ADC in white matter by 5.4% (P<0.05). ADC measurement can demonstrate subtle changes in the brain after GCC therapy that cannot be observed by conventional MR imaging. Measurement of ADC proved to be a sensitive means of assessing the effect of GCC therapy, even in the absence of visually discernible changes in conventional MR images.     

CT and MR imaging of CNS lymphomatoid granulomatosis

Summary The clinical CT and MR imaging features of a pathologically confirmed case of lymphomatoid granulomatosis are presented. The disease was clinically confined to the central nervous system and the diagnosis was only made after brain biopsy had been performed. MR imaging revealed extensive non-confluent regions of white matter abnormality. Although uncommon, lymphomatoid granulomatosis should be included in the differential diagnosis of causes of periventricular and deep white matter lesions, even in the absence of pulmonary lesions. Specific therapy may produce clinical regression of disease.     

Brain MR in chronic fatigue syndrome.

PURPOSETo determine the prevalence of MR white matter abnormalities in patients with chronic fatigue syndrome (CFS).METHODSBrain MR studies of 43 patients (29 women and 14 men, 22 to 78 years old) with a clinical diagnosis of CFS (n = 15), CFS with associated depression (n = 14), and CFS with associated other psychiatric disorders, namely, anxiety and somatization disorder (n = 14), were compared with brain MR studies in 43 age- and sex-matched control subjects.RESULTSMR findings were abnormal in 13 (32%) of the patients in the study group (ages 34 to 78 years) and in 12 (28%) of the control subjects (ages 26 to 73 years). One patient with CFS had multiple areas of demyelination in the supratentorial periventricular white matter. Another patient with CFS and associated depression had a single focus of probable demyelination in the supratentorial periventricular white matter. In four patients with CFS (ages 34 to 48 years) MR abnormalities consisted of one or several punctate hyperintense foci in the corona radiata, centrum ovale, and frontal white matter. The remaining seven patients (ages 50 to 78 years) had frontoparietal subcortical white matter foci of high T2 signal. The prevalence of white matter hyperintensities was not different between the patients and the control subjects.CONCLUSIONSOur findings suggest that no MR pattern of white matter abnormalities is specific to CFS.     

Increased self-diffusion of brain water in normal aging

With magnetic resonance (MR) imaging, brain water self-diffusion was measured in 17 healthy volunteers 22–76 (mean, 44.6) years old. The calculated values for the apparent diffusion coefficients (ADCs) ranged from 0.58 × 10^?9 to 1.23 × 10^?9 m²/sec in cerebral white matter. A significant correlation was found between the ADC in white matter and age (r =.7069, P <.01). The calculated values for ADC in cortical gray matter ranged from 1.06 × 10^?9 to 1.72 × 10^?9 m²/sec no correlation was found between ADCs in gray matter and age. The increased ADC in white matter may be caused by an increase in the extracellular volume due to age-dependent neuronal degeneration or to changes in myelination. These findings have implications for future clinical investigations with diffusion MR imaging techniques in patients with neurologic diseases, and stress the importance of having an agematched group of healthy volunteers for comparison.     

Premature aging in persons with Down syndrome: MR findings.

PURPOSETo determine whether persons with Down syndrome have features of premature aging on routine MR imaging sequences.METHODSSixty MR studies (in 30 persons with Down syndrome and 30 age- and sex-matched control subjects) were reviewed retrospectively by two blinded examiners. Sagittal T1-weighted and axial T2-weighted spin-echo images were evaluated for the presence and severity of three markers of brain aging: atrophy, white matter lesions, and T2 hypointensity of the basal ganglia, referenced to the examiner''s internal standard of normal for that age and sex.RESULTSPersons with Down syndrome had higher prevalence and severity of the three markers studied than the control subjects. Atrophy and white matter lesions increased in prevalence with age; abnormal T2 hypointensity of the basal ganglia was more equally distributed with age.CONCLUSIONPersons with Down syndrome have features of premature aging detectable at routine MR imaging.     

Systemic lupus erythematosus: brain MR imaging and single-voxel hydrogen 1 MR spectroscopy

PURPOSE: To evaluate the usefulness of magnetic resonance (MR) imaging and hydrogen 1 MR spectroscopy in the detection of brain involvement in patients with systemic lupus erythematosus (SLE) with or without neuropsychiatric symptoms. MATERIALS AND METHODS: Twenty-six patients who had SLE with (n = 17) or without (n = 9) neuropsychiatric symptoms were examined at MR imaging and (1)H MR spectroscopy. The voxel was placed in the basal ganglia and peritrigonal white matter. Eight healthy volunteers were included. RESULTS: Five of nine patients with major neuropsychiatric symptoms and one of eight patients with minor neuropsychiatric symptoms had abnormal MR imaging findings. (1)H MR spectroscopy showed a significantly decreased N:-acetylaspartate-creatine (Cr) ratio in the basal ganglia and an increased choline-Cr ratio in the peritrigonal white matter in patients with major symptoms compared with those with minor symptoms, those without symptoms, and healthy control subjects. Among patients with major symptoms, there was no difference in metabolite ratios between those with and those without abnormal MR imaging findings. Among patients with normal MR imaging findings, abnormal spectral changes were observed only in those with major neuropsychiatric symptoms. In patients without neuropsychiatric symptoms, results of (1)H MR spectroscopy and MR imaging were normal. CONCLUSION: In patients with SLE, (1)H MR spectroscopic findings seem to reflect the cerebral metabolic disturbance related to the severity of the neuropsychiatric symptoms and are not related to the presence of abnormal MR imaging findings.     

MR imaging of normal rat brain at 0.35 T and correlated histology.

A custom-built small-animal transceiver was used for in vivo imaging of normal rat brain at 0.35 T, with the objective of identifying anatomic components by comparison of images with corresponding histologic sections. The cerebrum, cerebellum, brain stem, ventricles, hippocampus, and subarachnoid space were identified and cerebrospinal fluid (CSF) was differentiated from gray matter and white matter on coronal and transaxial magnetic resonance (MR) images. These images compare favorably with those obtained by others at higher field strengths in regard to delineating major neuroanatomic structures. It is concluded that this technique will be useful for investigating small-animal models of human neurologic disease involving morphologic and morphometric changes in gray matter, white matter, and CSF-filled spaces.     

Pattern of white matter abnormalities at MR imaging: use of polymerase chain reaction testing of Guthrie cards to link pattern with congenital cytomegalovirus infection

PURPOSE: To define a magnetic resonance (MR) imaging pattern suggestive of congenital cytomegalovirus (CMV) infection by using polymerase chain reaction (PCR) testing to detect CMV DNA in neonatal blood on Guthrie cards for validation. MATERIALS AND METHODS: On the basis of findings in eight patients with documented congenital CMV infection, the authors developed MR imaging inclusion criteria, including multifocal lesions predominantly located in the deep parietal white matter. If gyral abnormalities were present, white matter lesions were either multifocal or diffuse. The criteria were applied to 152 patients with static leukoencephalopathy of unknown etiology. Guthrie cards for 22 of the 43 patients fulfilling the MR imaging criteria, 20 patients not fulfilling them, and 300 control subjects were analyzed. Fisher exact testing was used to evaluate the association between MR imaging characteristics and CMV status, and backward elimination linear discriminant analysis was used to identify MR imaging characteristics predictive of CMV infection in addition to the initial criteria. RESULTS: PCR test results were positive in 12 of 22 patients suspected of having congenital CMV infection, in no patient not suspected of having infection (P <.001), and in two of 300 control subjects (negative predictive value [NPV] of MR imaging criteria, 100% [95% CI: 83%, 100%]; positive predictive value [PPV], 55% [95% CI: 32%, 76%]). The most important additional MR imaging finding predicting a positive PCR result was abnormality of the anterior part of the temporal lobe, including abnormal white matter, cysts, and enlargement of inferior horns. Including this finding in the MR imaging criteria enhanced the PPV (89%; 95% CI: 52%, 99%) at the expense of the NPV (88%; 95% CI: 72%, 97%). CONCLUSION: In patients with static encephalopathy, an MR imaging pattern of multifocal lesions predominantly involving deep parietal white matter, with or without gyral abnormalities, is predictive of congenital CMV infection. When gyral abnormalities are present, leukoencephalopathy may also be diffuse. The presence of abnormalities in the anterior part of the temporal lobe increases the likelihood that CMV infection is present.     

Diffusion-Weighted Mr and Apparent Diffusion Coefficient in the Evaluation of Severe Brain Injury

Purpose: To study apparent diffusion coefficient (ADC) maps in severely brain-injured patients.Material and Methods: Four deeply comatose patients with severe brain injury were investigated with single-shot, diffusion-weighted, spin-echo echoplanar imaging. The tetrahedral diffusion gradient configuration and four iterations of a set of b-values (one time of 0 mm²/s, and four times of 1000 mm²/s) were used to create isotropic ADC maps with high signal-to-noise ratio. ADC values of gray and white matter were compared among patients and 4 reference subjects.Results: One patient was diagnosed as clinically brain dead after the MR examination. The patient's ADC values of gray and white matter were significantly lower than those of 3 other brain-injured patients. In addition the ADC value of white matter was significantly lower than that of gray matter.Conclusion: The patient with fatal outcome shortly after MR examination differed significantly from other patients with severe brain injury but non-fatal outcome, with regard to ADC values in gray and white matter. This might indicate a prognostic value of ADC maps in the evaluation of traumatic brain injury.     

MR imaging with quantitative diffusion mapping of tacrolimus-induced neurotoxicity in organ transplant patients

Our objective was to investigate brain MR imaging findings and the utility of diffusion-weighted (DW) imaging in organ transplant patients who developed neurologic symptoms during tacrolimus therapy. Brain MR studies, including DW imaging, were prospectively performed in 14 organ transplant patients receiving tacrolimus who developed neurologic complications. In each patient who had abnormalities on the initial MR study, a follow-up MR study was performed 1 month later. Apparent diffusion coefficient (ADC) values on the initial MR study were correlated with reversibility of the lesions. Of the 14 patients, 5 (35.7%) had white matter abnormalities, 1 (7.1%) had putaminal hemorrhage, and 8 (57.1%) had normal findings on initial MR images. Among the 5 patients with white matter abnormalities, 4 patients (80.0%) showed higher than normal ADC values on initial MR images, and all showed complete resolution on follow-up images. The remaining 1 patient (20.0%) showed lower than normal ADC value and showed incomplete resolution with cortical laminar necrosis. Diffusion-weighted imaging may be useful in predicting the outcomes of the lesions of tacrolimus-induced neurotoxicity. Electronic Publication     

Alzheimer病的海马体积测量及脑组织分割分析的初步研究

目的采用ＭＲ体积测量和组织分割分析对Ａｌｚｈｅｉｍｅｒ病（Ａｌｚｈｅｉｍｅｒｄｉｓｅａｓｅ，ＡＤ）患者和正常对照组进行研究，探讨其对ＡＤ的诊断价值。方法对临床诊断为ＡＤ患者和正常老年人各１６例作对照进行ＭＲＩ比较研究。测量两组的海马结构（ＨＦ）体积，脑灰质、脑白质、脑室外脑脊液（ＣＳＦ）和脑室ＣＳＦ体积所占颅内体积百分比，计数两组脑实质Ｔ２ＷＩ上的高信号灶并测量其最大径。结果体积测量显示ＡＤ组左、右侧ＨＦ体积均小于对照组。组织分割分析显示ＡＤ组脑灰质较对照组明显减少，脑室外ＣＳＦ和脑室ＣＳＦ体积所占颅内体积百分比较对照组增加，而脑白质两组间无显著性差异。ＡＤ组和对照组脑实质内高信号灶在大小和分布上无差异。结论ＭＲＨＦ体积测量和脑组织分割分析有助于临床了解ＡＤ的脑部形态结构改变，并能为ＡＤ的进一步诊断提供有价值的影像学评价指标。     

Fire-Related Post-Traumatic Stress Disorder: Brain 1H-MR Spetroscopic Findings

Objective

To investigate the MR imaging and ¹H-MR spectroscopic findings of acute fire-related post-traumatic stress disorder (PTSD).

Materials and Methods

Sixteen patients (M:F=10:6; mean age, 16 years) with fire-related PTSD underwent MR imaging and ¹H-MR spectroscopy, and for control purposes, the procedures were repeated in eight age-matched normal volunteers. In all patients and controls, the regions of interest where data were acquired at MRS were the basal ganglia (BG), frontal periventricular white matter (FWM), and parietal periventricular white matter (PWM).

Results

In all patients with PTSD, MR images appeared normal. In contrast, MRS showed that in the BG, NAA/Cr ratios were significantly lower in patients than in volunteers. This decrease did not, however, show close correlation with the severity of the neuropsychiatric symptoms. In patients, neither NAA/Cr ratios in FWM nor PWM, nor Cho/Cr ratios in all three regions, were significantly different from those in the control group.

Conclusion

Decreased NAA/Cr ratios in the BG, as seen at ¹H-MRS, might be an early sign of acute fire-related PTSD.     

Preliminary experience of magnetic resonance imaging in neurosarcoidosis

Summary Twelve MR scans performed on seven patients with neurosarcoidosis are presented. The most common abnormalities were ventricular enlargement (four patients) and diffuse periventricular white matter changes (three patients). Infarcts were seen in three patients and mass lesion in one. The lesions were seen in both T1 and T2 weighted images. The results are compared with CT findings. MRI seems to be more sensitive than CT in detecting white matter changes and infarcts. Ventricular enlargement and granulomas were equally well seen with both modalities.