Early Subacute Stage Research Articles

Disturbance of thiol/disulfide aminothiols homeostasis in patients with acute ischemic stroke stroke: Preliminary findings

ObjectivesTo determine the disruption of low-molecular-weight aminothiols (LMWTs: cysteine, cysteinylglycine, homocysteine, and glutathione) homeostasis in blood plasma during the acute and early subacute stages after ischemic stroke. Patients and methodsWe admitted 41 patients with primary large-artery atherosclerosis and cardioembolic stroke in the carotid arteries within the first 6–24 h from the moment of neurologic symptoms development. We included 31 patients with chronic cerebral ischemia in the control group. Total LMWT levels and their reduced forms were measured in blood plasma on the 1st, 3rd, 7th, and 15th days after stroke. ResultsOur study demonstrated a decrease of cysteine and cysteinylglycine reduced forms and an increase of total glutathione and cysteine levels. There were no differences in LMWT levels among stroke subtypes (large-artery atherosclerosis and cardioembolic stroke). The decrease (or increase) in GSH and Hcy redox status on the 3rd day after stroke was associated with severe neurological deficit. Total Hcy (1st day), Cys (3rd day) and CG(7th day) levels were associated with the size of cerebral infarction area. Logistic regression analysis indicated that reduced homocysteine, total cysteinylglycine levels, and cysteine redox status at admission were predictive factors for ischemic stroke occurrence with a probability of 86.2% (p < 0.001). ConclusionsLMWTs may indicate the severity of neurological deficit and the size of the cerebral infarct, and their complex determination can be of diagnostic importance both at an early stage of ischemic stroke development and during its monitoring.

Replication and novel analysis of age and sex effects on the neurologic and functional value of each spinal segment in the US healthcare setting.

Replication of previously developed prognostic model. In motor complete injuries at admission to rehabilitation, perform; (1) replication analyses of the relationships between ISNCSCI motor level and motor scores and SCIM and (2) novel analyses to determine if age and/or sex moderate relationship between neurological impairment and function. Admission to initial inpatient rehabilitation in the United States. Post-Hoc analyses of data collected as part of a separate study. Replication analyses: (1) Pearson's correlation assessed relationship strength between neurologic impairment and function. (2) Multiple linear regression assessed if center or age influenced functional outcome. Novel analyses: (1) Moderated multiple regression assessed if age and/or sex moderated the lesion level-function relationship. Of the 406 datasets, 161 were motor complete injuries, and included in the analyses. Median time post injury at admission to rehabilitation was 19 days. Our replication analyses confirmed the neurologic and functional value of each spinal segment reported by the EM-SCI group (all p ≤ 0.018). We failed to confirm their reported age effect (p = 0.05) and non-effect of center (p = 0.037). Our novel analyses indicated that age coded as above/below 50 moderated the relationship between neurologic impairment and function (p = 0.038) in cervical injuries only, but that age coded as above/below 35 (all p ≥ 0.510) and sex (all p ≥ 0.465) did not. The neurological and functional value of each segment is consistent across very different healthcare settings in early and late sub-acute stages and minimally impacted by age and sex. Differences related to centers and age may confound efficacy trials. The Miami Project to Cure Paralysis; The Craig H. Neilsen Foundation (83492).

Evolution of intramural duodenal hematomas on magnetic resonance imaging.

The magnetic resonance imaging (MRI) characteristics of evolving duodenal hematomas in children are unknown. To describe the MRI changes exhibited by evolving duodenal hematomas and the likely mechanisms behind these changes. We retrospectively reviewed the MR features of intramural duodenal hematomas (6 lesions, 10 examinations) studied on a 1.5-T MR unit. All patients had clinical histories of blunt abdominal trauma or endoscopic procedures and we were able to determine the time interval between the onset and MR imaging. We evaluated and analyzed the appearance and signal intensity patterns of hematomas of varying ages and we compared the results with those in previously reported intracranial hematomas. The imaging appearances on five examinations were consistent with presence of deoxyhemoglobin. Two of these lesions were hypointense on T2-weighted images and iso- to hyperintense on T1-weighted images. Three had heterogeneous appearances on both T1- and T2-weighted images, and the bulk of the hematoma progressively increased in size and signal intensity on T2-weighted images. On the remaining five examinations, one lesion was hyperintense on T1-weighted images and iso- to hyperintense on T2-weighted images, consistent with intracellular methemoglobin, and four lesions were hyperintense on both T1- and T2-weighted images, consistent with the presence of extracellular methemoglobin. Duodenal hematoma stages were slower than those of intracranial hematomas; the acute stage spanned 2-7 days, and early and late subacute stages occurred 10-17 days after the injury. Duodenal hematomas evolve like intracranial hematomas, but slower. Signal heterogeneity is common in the acute stage.

Use of T1 relaxation time in rotating frame (T1 ρ) and apparent diffusion coefficient to estimate cerebral stroke evolution.

The major factor for the appropriate treatment strategies for ischemia patients is its onset timing. To study to evaluate the diagnostic accuracy of T1 relaxation time in a rotating frame (T1 ρ) and apparent diffusion coefficient (ADC) from MRI to estimate ischemia stages. Prospective. In all, 73 patients (49 males, aged 29-78 years and 24 females, aged 22-94 years) with ischemia were prospectively imaged with T1 ρ and diffusion MRI during the postischemic period. 3T/T1 ρ and diffusion-weighted imaging (DWI). Ischemic parenchyma included tissue with elevated signal areas on DWI and correlative hypointense areas on ADC maps. The sensitivity of variables to ischemia time was quantified by analyzing the respective correlations of these values with onset time. ΔT1 ρ (ipsilateral-contralateral differences in T1 ρ) (R2 = 0.956) and T1 ρipsi (ipsilateral ischemia T1 ρ values) (R2 = 0.941) were elevated in all ischemic lesions; these values increased linearly as a function of time, unlike ΔADC (ipsilateral-contralateral differences in ADC) (R2 = -0.410) and ADCipsi (ipsilateral ischemia ADC values) (R2 = 0.550). ΔT1 ρ and T1 ρipsi were significantly different between all stages (P < 0.01), except the acute and hyperacute stages (P = 0.589 for ΔT1 ρ, P = 0.290 for T1 ρipsi , respectively), but ΔADC and ADCipsi only between the late subacute and early subacute stages (P < 0.01) and the late subacute and chronic stages (P < 0.01). These data suggest that T1 ρ can provide estimates for the ischemic time in patients. T1 ρ has the potential to outperform diffusion for single-timepoint examination because the T1 ρ change during strokes is positive and linear. If patients with suspected stroke are scanned by MRI within the appropriate timeframe, T1 ρ may provide tools for evaluating stroke onset, potentially aiding in treatment strategies. 4 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1247-1254.

Evolution of Cerebral Ischemia Assessed by Amide Proton Transfer-Weighted MRI.

Amide proton transfer-weighted (APTW) magnetic resonance imaging (MRI) has recently become a potentially important tool for evaluating acidosis in ischemic stroke. The purpose of this study was to evaluate the dynamic pH-related changes in the lesions in patients with ischemia. Thirty-nine patients with ischemic stroke (symptom onset to imaging time ranging 2 h–7 days) were examined with a 3.0-T MRI system. Patients were divided into four groups: at the hyperacute stage (onset time ≤ 6 h), at the acute stage (6 h < onset time ≤ 48 h), at the early subacute stage (48 h < onset time ≤ 96 h), and at the late subacute stage (96 h < onset time ≤ 168 h). The APTW signal intensities were quantitatively measured in multiple ischemic regions for each patient. Compared with the contralateral normal white matter, APTW signals were significantly lower in ischemic tissue for all four stages (P < 0.05). The APTW signal intensities (APTWave and APTWmin) increased consistently with onset time (R2 = 0.11, P = 0.040; R2 = 0.13, P = 0.022, respectively). APTWmax–min showed a continued reduction with onset time (R2 = 0.44, P < 0.001). Our results suggest that persistent tissue acidification could occur after ischemia, and as the time from stroke onset increases, the acidotic environment would alleviate. APTW signal intensities could reflect pH-weighted properties in ischemic tissue at different stages and time points.

Early spermatogenesis changes in traumatic complete spinal cord-injured adult patients.

Prospective longitudinal study. To assess the impact of spinal cord injury (SCI) on the spermatogenesis of patients studied in the early subacute stage and ensuing months. National hospital for SCI patients. A prospective follow-up study was conducted on 28 male patients with complete SCI who were evaluated in the early subacute phase (~1 month), and 3 and 6 months after the injury. At each time point, fine needle aspiration biopsy samples were taken from the testes for cytological assessment, and serum levels of relevant hormones were measured. At the end of the study period, ejaculation was attempted for standard semen analyses. Cytological patterns indicative of defective spermatogenesis were found in 61%, 52% and 20% of the patients at 1, 3 and 6 months after SCI, respectively, suggesting an improvement over time. Serum hormone analyses showed a steady elevation of estradiol levels above the reference range, and increasing levels of testosterone, inhibin B and prolactin throughout the study period. Prolactin levels were above the reference range at all time points. Only 2 out of the 10 patients who were able to ejaculate at 6 months post injury showed normal sperm parameters. A majority of the patients showed impaired spermatogenesis soon after the injury, which in most cases recovered over time. That was accompanied by parallel increases in serum levels of inhibin B, testosterone and prolactin, possibly driving or reflecting the spermatogenesis recovery. Further studies are needed to elucidate the biological mechanisms underlying these changes.

Detection and differentiation of early acute and following age stages of myocardial infarction with quantitative post-mortem cardiac 1.5 T MR

Recently, quantitative MR sequences have started being used in post-mortem imaging. The goal of the present study was to evaluate if early acute and following age stages of myocardial infarction can be detected and discerned by quantitative 1.5T post-mortem cardiac magnetic resonance (PMCMR) based on quantitative T1, T2 and PD values.In 80 deceased individuals (25 female, 55 male), a cardiac MR quantification sequence was performed prior to cardiac dissection at autopsy in a prospective study. Focal myocardial signal alterations detected in synthetically generated MR images were MR quantified for their T1, T2 and PD values. The locations of signal alteration measurements in PMCMR were targeted at autopsy heart dissection and cardiac tissue specimens were taken for histologic examinations. Quantified signal alterations in PMCMR were correlated to their according histologic age stage of myocardial infarction.In PMCMR seventy-three focal myocardial signal alterations were detected in 49 of 80 investigated hearts. These signal alterations were diagnosed histologically as early acute (n=39), acute (n=14), subacute (n=10) and chronic (n=10) age stages of myocardial infarction. Statistical analysis revealed that based on their quantitative T1, T2 and PD values, a significant difference between all defined age groups of myocardial infarction can be determined. It can be concluded that quantitative 1.5T PMCMR quantification based on quantitative T1, T2 and PD values is feasible for characterization and differentiation of early acute and following age stages of myocardial infarction.

Clinical trial design for stem cell therapies in stroke: What have we learned?

Stem cells of various sources have been investigated in a series of small, safety and feasibility-focused studies over the past 15 years. Understanding of mechanisms of action has evolved and the trial paradigms have become focused on two different approaches – one being an early subacute delivery of cells to reduce acute tissue injury and modify the tissue environment in a direction favourable to reparative processes (for example by being anti-inflammatory, anti-apoptotic, and encouraging endogenous stem cell mobilisation); the other exploring later delivery of cells during the recovery phase after stroke to modulate the local environment in favour of angiogenesis and neurogenesis. The former approach has generally investigated intravenous or intra-arterial delivery of cells with an expected paracrine mode of action and no expected engraftment within the brain. The latter has explored direct intracerebral implantation adjacent to the infarct. Several relevant trials have been conducted, including two controlled trials of intravenously delivered bone marrow-derived cells in the early subacute stage, and two small single-arm phase 1 trials of intracerebrally implanted cells. The findings of these studies and their implications for future trial design are considered.

Multi-Contrast High-Resolution Magnetic Resonance Findings of Spontaneous and Unruptured Intracranial Vertebral Artery Dissection: Qualitative and Quantitative Analysis According to Stages

Background: Although high-resolution magnetic resonance imaging (HR-MRI) has been used as a strong imaging method for diagnosing intracranial vertebral artery dissection (IVAD), the diagnosis is sometimes challenging because a dissection has geometric changes in the natural course. The radiologic features may change or disappear over time, which makes the diagnosis confusing. Our study was to present radiological findings according to the stages in spontaneous and unruptured, IVAD on 3T HR-MRI and to guide the age estimation of IVAD with the distinguishing findings according to the stages. Methods: From January 2011 to July 2014, the 41 vertebral arteries (M:F = 18:12; age range 32-67 years) were retrospectively enrolled. Spontaneous, unruptured IVAD was diagnosed if it had a clear onset based on clinical and radiological findings. The stages were classified as acute (0-3 days), early subacute (3-10 days), late subacute (10-60 days) and chronic stage (>60 days; recovery and non-recovery groups) according to the time intervals from symptom onset, based on the prior published studies. HR-MR findings were assessed and compared in the intimal flap, double lumen, aneurysmal dilatation (maximal outer diameter, maximal wall thickness, wall thickness index and remodeling index), intramural hematoma (relative signal intensity) and vessel wall enhancement according to the stages with qualitative and quantitative methods. Two radiologists analyzed the HR-MR findings with consensus reading. Results: IVAD was classified into acute (n = 6), early subacute (n = 8), late subacute (n = 16) and chronic (n = 11) stages. HR-MR dissection findings such as intimal flap, double lumen, aneurysmal dilatation and intramural hematoma significantly decreased from the earlier stages to the chronic stage (p < 0.05). The quantitative indices in aneurysmal dilatation and the relative signal intensity of intramural hematoma showed significant higher values in the earlier stages followed by a significant decrease in the chronic stage recovery group (p < 0.05). The degree of vessel wall enhancement was higher in the earlier stage and decreased in the chronic stage (p < 0.05), but mild vessel wall enhancement was identified 900 days after symptom onset. Conclusion: The 3T HR-MRI reveals the vessel wall characteristics and provides distinguishing findings between earlier stages and the chronic stage in spontaneous and unruptured IVAD. Characterization of these radiological findings according to stages may assist with the age estimation of the dissection and may help to understand IVAD as a whole.

Quantitative Susceptibility Mapping of Intracerebral Hemorrhages at Various Stages.

To investigate the magnetic susceptibility of intracerebral hemorrhages (ICH) at various stages by applying quantitative susceptibility mapping (QSM). Blood susceptibility was measured serially using QSM after venous blood withdrawal from healthy subjects. Forty-two patients who provided written consent were recruited in this Institutional Review Board-approved study. Gradient echo magnetic resonance imaging (MRI) data of the 42 patients (17 females; 64 ± 12 years) with ICH were processed with QSM. The susceptibilities of various blood products within hematomas were measured on QSM. Blood susceptibility continually increased and reached a plateau 96 hours after venous blood withdrawal. Hematomas at all stages were consistently hyperintense on QSM. Susceptibility was 0.57 ± 0.48, 1.30 ± 0.33, 1.14 ± 0.46, 0.40 ± 0.13, and 0.71 ± 0.31 ppm for hyperacute, acute, early subacute, late subacute, and chronic stages of hematomas, respectively. The susceptibility decrease from early subacute (1.14 ppm) to late subacute (0.4 ppm) was significant (P < 0.01). QSM reveals positive susceptibility in hyperacute hematomas, indicating that even at their hyperacute stage, deoxyhemoglobin may exist throughout the hematoma volume, not just at its rim, as seen on conventional T2* imaging. QSM also reveals a reduction of susceptibility from early subacute to late subacute ICH, suggesting that methemoglobin concentration decreases at the late subacute stage. J. Magn. Reson. Imaging 2016;44:420-425.

Diffusion-weighted magnetic resonance imaging in a case of Kernohan's notch phenomenon

Dear Editor, Kernohan's notch phenomenon is characterized by false localizing motor signs caused by compression of the cerebral peduncle against the tentorial edge, contralateral to a supratentorial mass [3]. Using magnetic resonance imaging (MRI), several cases of this phenomenon due to traumatic acute subdural hematomas were reported. A case of Kernohan's notch phenomenon with diffusionweighted (DW) MRI in a chronic stage was reported before [5]. We present a case of Kernohan's notch phenomenon secondary to a traumatic acute subdural hematoma where MRI, mainly DW images, showed visibly abnormal findings in the early subacute stage. A 19-year-old male felt nauseous after boxing. Soon afterwards he became unconscious following which he was transferred to a local hospital. After being diagnosed with an acute subdural hematoma (Fig. 1a), he was intubated and transferred to our hospital. In the emergency room his Glasgow Coma Scale score was 7. He was able to move his right extremities but his left extremities exhibited an extended posture. Light reflex of the left pupil was sluggish. Babinski signs were negative bilaterally. Subsequently, a left craniotomy was performed with evacuation of the subdural hematoma 6 h after the onset. Postoperatively, his pupillary reaction normalized. He began to regain consciousness and gradually the right motor function improved; however, the left hemiplegia persisted. After 21 days, the patient had persistent left hemiparesis and was transferred to another hospital for rehabilitation. MRI (1.5 T Philips Intera) performed 7 days after the operation revealed that the subdural hematoma was successfully evacuated. However, T2-weighted MRI revealed a lesion in the right cerebral peduncle (Fig. 1b, c). Furthermore, DW imaging (EPI Matrix 256×256, FOV=230 mm, TR/TE=2721/72 ms, b=1,000 mm/s, thickness=5 mm) revealed the lesion to be hyperintense (Fig. 1d). The apparent diffusion coefficient (ADC) map showed the area as a low signal (Fig. 1e), and it had a relatively low ADC value (0.78×10 mm/s) compared to that of the contralateral cerebral peduncle (0.90×10 mm/s). Besides conventional MRI, Binder et al. first reported Kernohan's notch phenomenon with transcranial magnetic stimulation [2]. Later Yoo et al. reported a case of Kernohan's notch phenomenon with diffusion tensor imaging, which is the only published case where DW imaging was used [5], here, MRI was performed 6 weeks after the onset, fraction anisotropy (FA) and ADC values were shown but DW image was not included. The FA value decreased in the affected cerebral peduncle, but a marked difference was not seen between ADC values on the contralateral side or in the control subjects. Marmarou, Barzo et al. conducted clinical and experimental studies on traumatized brains. They reported that increased intracellular water volume and reduced ADC value indicates cytotoxic edema. During the subacute stage, axonal injury causes a reduced ADC value after traumatic S. Uesugi (*) Department of Neurosurgery, Kanmon Medical Center, 1-1 Sotouracho, Chofu, Shimonoseki, Yamaguchi 7520985, Japan e-mail: uesugis@simonoseki2.hosp.go.jp

Quantitative Neuroimaging and the Prediction of Rehabilitation Outcome Following Traumatic Brain Injury

Quantitative Neuroimaging and the Prediction of Rehabilitation Outcome Following Traumatic Brain Injury

Cerebrospinal Fluid Concentrations of Nitric Oxide Metabolites in Spinal Cord Injury

Multiple center study to evaluate cerebrospinal fluid (CSF) concentrations of nitric oxide metabolites [NOx] in relation to neurologic severity and prognosis in spinal cord injury (SCI). To examine whether CSF [NOx] correlates with neurologic severity and recovery in SCI. Inducible nitric oxide synthase is expressed in rat spinal cord immediately after SCI. Excessive nitric oxide production is cytotoxic, causing neuronal apoptosis with subsequent neurodysfunction in the spinal cord. We previously reported a significant correlation between initial [NOx] after incomplete cervical cord injury (CCI) and neurologic recovery at the final follow-up in 25 cases. Ninety-six cases (SCI group), including 76 patients with CCI and 20 patients with thoracic cord injury were examined. Mean follow-up period was 11 months. The control group comprised 40 cases (3 healthy volunteers and 37 patients with neither pain nor neurologic disorders). CSF [NOx] were measured using the Griess method. Severity of neurologic impairment was assessed using Frankel's classification and the American Spinal Injury Association motor score (ASIA MS). Degree of neurologic recovery was assessed using Frankel's classification and the ASIA motor recovery percentage. CSF [NOx] did not differ significantly among the control, CCI, and thoracic cord injury groups at the initial examination. In the CCI group, [NOx] in the Frankel A and B classes were significantly higher than [NOx] in the control group at 5 to 14 days, in the Frankel A and B classes at 0 to 4 days, and in the Frankel C and D classes at 5 to 14 days. Also, in the CCI group at 5 to 14 days, [NOx] correlated significantly with ASIA MS and motor recovery percentage. There was a significant correlation between CSF [NOx] at the pathologic early subacute stage (approximately 5-14 days) and neurologic severity and recovery in SCI.

Monitoring After the Acute Stage of Stroke

In the early stage of stroke, the occurrence of neurologic and medical complications is associated with clinical deterioration. Previous studies were focused on the first week after stroke onset. The aim of this study was to evaluate the impact of complications on clinical outcome in patients with stroke in the early subacute stage. We prospectively evaluated the influence on the outcome of complications feasible (MC) and not feasible for monitoring (NMC) in all patients with stroke admitted consecutively in our subacute stroke unit. Patients were divided into three classes according to stroke severity evaluated by the National Institutes of Health Stroke Scale score. A change in the National Institutes of Health Stroke Scale score group from admission to discharge was considered clinically significant. We included 261 patients. Sixty percent of patients had complications (105 MC, 118 NMC). Hyperthermia (OR=14.12; 95% CI: 6.01 to 33.20), urinary infections (OR=4.92; 95% CI: 2.19 to 11.04), hypertension (OR=2.86; 95% CI: 1.21 to 6.76), hypoxia (OR=15.75; 95% CI: 6.73 to 36.84), and neuroradiologic damage progression (OR=58.31; 95% CI, 19.48 to 174.55) were associated with a change to a more severe class at discharge and with a higher risk of mortality. A high percentage of patients can develop both MC and NMC during this subacute stage of stroke. The occurrence of complications influences outcome and raises the question about the need for a prolonged stay in a dedicated ward for patients with stroke.

Measurement of DTI metrics in hemorrhagic brain lesions: Possible implication in MRI interpretation

To understand the biological basis of possible mechanisms responsible for increased fractional anisotropy (FA) in different stages of hemorrhage and hemorrhagic brain lesions. A total of 19 patients with cerebral hemorrhage (CH), five patients with hemorrhagic infarct (HI), and nine patients with hemorrhagic brain tumor (HBT) were prospectively evaluated with diffusion tensor imaging (DTI) and the FA and mean diffusivity (MD) was quantified. Ex vivo DTI of blood clot and histology of the blood clot and HBT were performed to interpret the temporal changes in the DTI metrics. High FA (>0.20) with low MD in the acute and early subacute stage and low FA (<0.20) with increased MD in the late subacute and chronic stage of CH and HI were observed. HBT showed high FA with low MD at all stages. In CH and HI, a significant reduction in FA (P < 0.001) with increased MD (P < 0.001) was seen in the late subacute and chronic stages compared to the acute and early subacute stages, normal white matter (NWM), and HBT. In HBT, there was no significant statistical difference in the FA values between different stages. Histology of HBT and ex vivo blood clot showed structural organization of intact red blood cells (RBCs) with fibrin mesh where the FA values were high compared to normal tissue region that is devoid of blood. Intact RBCs entangled within fibrin mesh appear to be responsible for high FA in hemorrhagic brain lesions.

Serial proton magnetic resonance spectroscopy in lesions of Balò concentric sclerosis.

Balò concentric sclerosis is a rare demyelinating disorder. Serial proton magnetic resonance spectroscopic (1H-MRS) studies were carried out to better understand the biochemical changes within concentric lesions. Five concentric lesions in four patients with Balò concentric sclerosis were chosen as the objects of serial observation. They included two early acute lesions (showing as concentric ring enhancement on magnetic resonance imaging (MRI) after gadolinium administration), two late acute lesions (showing as marginal enhancement on MRI), and one early subacute lesion (showing as edematous concentric lesions without enhancement on MRI). The duration of follow-up ranged from 2-23 months (mean 10 months). A total of 20 1H-MRS studies were performed. On each 1H-MRS study, short-echo (30 ms) and long-echo (136 ms) spectra were obtained. The peaks of N-acetyl-asparate (NAA), choline-containing compounds (Cho), creatine and phosphocreatine (Cr), lactate, and mobile lipid were observed and compared. Generally, a decrease of NAA/Cr ratio and an increase of Cho/Cr ratio were seen on all the spectra. Observing longitudinally, a trend of decreasing NAA/Cr ratio first and then partially recovering later was noted. The lowest level of NAA/Cr ratio was noted at the late acute stage or early subacute stage. The Cho/Cr ratio and amplitude of the lactate peak showed a similar trend as that of NAA/Cr, but in an opposite direction. It was rising first and descending later. The highest levels of Cho/Cr ratio and lactate peak were also observed at the late acute or early subacute stage. In addition, lactate peaks could be detected as long as 7 months after onset of symptoms. Lipid metabolite (two broad peaks at 0.9-1.5 ppm) was seen at the initial study of each group, but fluctuated in size on follow-up. The characteristic biochemical changes of concentric sclerosis were a decreased NAA/Cr ratio, an increased Cho/Cr ratio, two broad peaks at 0.9-1.5 ppm, lactate production, and a reversible NAA/Cr ratio on follow-up. The serial 1H-MRS studies revealed a strong biochemical association between NAA, Cho, and lactate, which may be caused by the same pathogenetic process of demyelination and inflammatory cellular infiltration. The specificity of the serial changes may provide information about the stage of the concentric lesion and perhaps aid in monitoring progression of concentric lesions and evaluating therapy.

Acute Carbon Monoxide Intoxication: The Relation between MR Findings and Clinical Outcome

Purpose: To analyse MR findings of various involving sites and the relation between such findings and clinical outcome, the authors retrospectively reviewed MR images of acute carbon monoxide intoxication. Materials and Methods: In 12 patients, MR images obtained from several hours to 12 days after acute carbon monoxide intoxication were reviewed. The images were analysed with regard to involved sites, symmetricity, signal intensity, and the presence or absence of hemorrhage, and the relationship between MR findings and clinical outcome; the presence of delayed encephalopathy was then determined. Results: The globus pallidus(n=9), white matter{(n=3), [centrum semiovale(n=2), periventricular white matter(n=1)] and gyrus(n=6) [inferior temporal gyrus(n=2), cingulate gyrus(n=1), precentral gyrus(n=1), hippocampal gyrus(n=1), parahippocampal gyrus(n=1)] were typically involved, and there was also involvenent of the corpus callosum(n=3), thalamus(n=2) and midbrain(n=2). All lesions of the globus pallidus, thalamus, midbrain and temporal lobe were bilaterally symmetric. In all these cases, subtle or prominent low signal intensity was seen on spin-echo T1WI, and high signal intensity on PDWI and T2WI. Some lesions of the globus pallidus(n=1), thalamus(n=1) and midbrain(n=1) were associated with hemorrhage, which occurred during the early subacute stage and was seen on high/low signal intensity T1/T2WI images. Acute cerebral(n=1) and cerebellar(n=1) infarctions were also seen. Cerebral white matter involvement correlated with poor clinical outcome, and in two cases, delayed encephalopathy developed. Conclusion: In these cases of acutecarbon monoxide intoxication, the globus pallidus, white matter, cortex and hippocampus were frequently involved, and there was also involvement of various sites such as the corpus callosum, thalamus and midbrain. Lesions of the temporal lobe, thalamus and midbrain were bilaterally symmetric. The involvement of cerebral white matter and the presence of delayed encephalopathy can influence clinical outcome.

Magnetic resonance characteristics of intrapelvic haematomas

Although haematomas in the female pelvis are not rare, their magnetic resonance (MR) appearance has not been well characterized. Accordingly, we analysed the MR appearances of various stages of haematomas in the female pelvis. A retrospective analysis of 35 haematomas in 28 patients sequentially imaged with a 1.5 T MR unit was performed. The time interval between the insult and MR imaging was determined and the appearances of the haematoma were evaluated. The results were compared with those in the central nervous system. The evolution of haematomas in the pelvis appeared similar to that of haematomas in the brain, and four stages (acute, early subacute, late subacute and chronic) were identified according to the signal intensity pattern on T1 and T2 weighted images. Pelvic haematomas differed from intracranial haematomas in the following features: (1) The speed of evolving pelvic haematomas was gradual. (2) In the centre of acute haematomas, slightly hyperintense areas were seen on both sequences, suggesting residual oxyhaemoglobin. (3) Haematomas evaluated in the early subacute stage had complex appearances. (4) In older haematomas, central intermediate signal intensity areas, presumably due to diamagnetic hemichromes, became predominant on T1 weighted images. In conclusion, although the evolution of a pelvic haematoma is similar to that of a brain haematoma, its speed is gradual and MR appearances are somewhat different due to environmental differences.

Hypoxic brain damage: cortical laminar necrosis and delayed changes in white matter at sequential MR imaging.

To report the findings of sequential magnetic resonance (MR) imaging in hypoxic encephalopathy. Three women and three men underwent repeated MR imaging studies. Sequential changes in signal intensity and morphologic features of the brain were evaluated. Involvement of the watershed zones in the parietooccipitotemporal cortex was more frequent and more severe than that in the basal ganglia, thalami, hippocampus, pons, and cerebellum. Cerebral edema was seen in the acute stage. Enhanced T1-weighted images showed cortical laminar enhancement in the early subacute stage; unenhanced T1-weighted images revealed characteristic laminar hyperintense lesions of the cerebral cortex in the late subacute stage. Both of these findings seemed to reflect the progression of cortical laminar necrosis. In the chronic stage, cortical atrophy and delayed but progressive white matter changes were seen. Changes in MR imaging features of hypoxic brain damage are complex but distinct. Cortical laminar necrosis, delayed white matter degeneration, and, probably, increased iron deposition in the white matter can be delineated.

MR imaging of intracranial hemorrhage in neonates and infants at 2.35 Tesla

The variations of the relative signal intensity and the time dependent changing contrast of intracranial hemorrhages on high-field spin-echo magnetic resonance images (MRI) were studied in 28 pediatric patients. For T1-weighted images, a repetition time (TR) of 500 ms and an echo time (TE) of 30 or 23 ms was used. The corresponding times for T2-weighted images were TR 3000 ms and TE 120 ms. Intracranial hematomas, less than 3 days old, were iso- to mildly hypointense on short TR/TE scans and markedly hypointense on long TR/TE scans (acute stage). In the following four days the signal of the hematomas became hyperintense on short TR/TE scans, beginning in the periphery and proceeding towards the center. On long TR/TE scans the signal remained markedly hypointense (early subacute stage). 7-14 days old hematomas were of high signal intensity on short TR/TE scans. On long TR/TE scans they appeared hypointense in the center and hyperintense in the periphery (late subacute stage). By the end of the second week the hematomas were of high signal intensity on all pulse sequences (chronic stage). Chronic hematomas were surrounded by a parenchymal rim of hypointensity on long TR/TE scans. 28 neonates and infants (with 11 follow-up examinations) of 31.5-70.6 weeks postconceptional age (PCA), with an intracranial hemorrhage were examined. The etiologies of the hemorrhages were: asphyxia (17 cases), brain infarct (2), thrombocytopenia (1), clotting disorder (1) and unknown origin (7). The aim of this study was to describe the appearance of intracranial hemorrhages in neonates and infants with MRI at 2.35 Tesla using spine-cho sequences.