Quantitative analysis of the lung CT in normal subjects and in patients with noncardiac pulmonary edema

A quantitative analysis was performed of the CT images relative to 7 normal human subjects and to 22 patients affected with ARF (Acute Respiratory Failure). The CT scanner image quality was investigated, and the unit was checked with quality control procedures, in order to assure reliability and reproducibility. In every patient the lung was scanned at 3 different levels--basis, hilum and apex. The frequency distribution of CT numbers was studied. The lung areas were calculated for the different conditions, and the data correlated with functional lung data. A method was then tested to evaluate lung weight; the data obtained did not differ from literature data. All the patients were treated with different positive and expiratory pressure (PEEP). For different PEEP values, the quantitative data from CT analysis were correlated with morphofunctional indices.     

Cerebrocerebellar relationships in normal subjects and patients with dementia of the Alzheimer type: a SPECT study

The relationships between blood flow in the cerebrum and the cerebellum was investigated in 21 normal subjects and 21 patients with dementia of the Alzheimer type (DAT). In normal subjects, only asymmetry in the frontal cortical blood flow was significantly correlated with asymmetry in the contralateral cerebellar blood flow. However, a significant correlation between asymmetry in the cerebral cortical blood flow in many areas and the blood flow in the contralateral cerebellum in DAT patients was observed. These results suggest the existence of a functional relationship between the cerebrum and the cerebellum in both normal and DAT groups, mediated by neuronal mechanisms through crossed fiber pathways. However, there are regional differences in the cerebrocerebellar relationship in normal resting and pathological states.     

CT measurements of cranial growth: normal subjects

Growth patterns of the cranium measured directly as head circumference have been well documented. With the availability of computed tomography (CT), cranial dimensions can be obtained easily. The objective of this project was to establish the mean values and their normal variance of CT cranial area of subjects at different ages. Cranial areas and its long and short axes were measured on CT scans for 215 neurologic patients of a wide age range who presented no evidence of abnormal growth of head size. Growth patterns of the cranial area as well as the numeric product of its linear dimensions were determined via a curve fitting process. The patterns resemble that of the head circumference growth chart, with the most rapid growth observed in the first 12 months of age and reaching full size during adolescence. It is believed that the availability of such reference, in addition to the head circumference measurement, will be valuable to the CT reviewer in determining the growth status of head size.     

Hippocampal sulcus width and cavities: comparison between patients with Alzheimer disease and nondemented elderly subjects

BACKGROUND AND PURPOSE: The hippocampal fissure is a fetal sulcus that, except for its most medial part (the superficial hippocampal sulcus), is normally obliterated. Hippocampal cavities are residual cysts attributable to lack of hippocampal fissure obliteration. We hypothesized that either hippocampal sulcus enlargement or an increase in number or size of hippocampal cavities could be associated with medial temporal lobe atrophy (MTA) occurring in Alzheimer disease. METHODS: Two observers assessed the maximal hippocampal sulcus width by means of the fimbriosubicular distance at the anterior part of the hippocampal body; as well as the occurrence, number, and size of hippocampal cavities; and the visual rating score of MTA on magnified coronal high-resolution T1-weighted MR images of 21 patients with Alzheimer disease and 15 nondemented elderly controls. RESULTS: Both observers found the maximal hippocampal sulcus width significantly larger in patients with Alzheimer disease than in controls (P < .0001). The interobserver averaged fimbriosubicular distance in patients with Alzheimer disease was 2.84 mm (SD = 0.94), approximately twice that of the corresponding distance in nondemented subjects (1.41 mm; SD, 0.58). Both observers found a significant correlation between the fimbriosubicular distance and MTA score (observer 1, r(s) = 0.71; observer 2, r(s) = 0.74; P < .0001). None of the observers found significant differences between patients with Alzheimer disease and nondemented subjects with respect to occurrence, number, or size of hippocampal cavities, nor did they find a significant correlation between the number or size of hippocampal cavities and MTA. Interobserver agreement ranged from moderate to very good. CONCLUSION: Enlargement of the hippocampal sulcus, assessed by the fimbriosubicular distance, is associated with MTA in Alzheimer disease, but enlargement of the hippocampal cavities is not.     

Application of principal component analysis in vertical ground reaction force to discriminate normal and abnormal gait

Discrete parameters from ground reaction force (GRF) are been considered in gait analysis studies. However, principal component analysis (PCA) may provide additional insight into gait analysis for considering the complete pattern of GRF. This study aimed at testing the application of PCA to discriminate the vertical GRF pattern between control group (CG) and patients with lower limb fractures (FG), as well as proposing a score to quantify the abnormality of gait. Thirty-eight healthy subjects participated of CG and 13 subjects in FG, five subjects from FG were also evaluated after physiotherapeutic treatment (FGA). The GRF was measured by an instrumented treadmill. Principal component coefficients (PCCs) were obtained by singular value decomposition using GRF of complete stride. Two, four and six PCCs were used to obtain the standard distance (D). The classification between groups was mainly given by the first PC, which indicated higher loading factors during push off of affected side and heel strike of unaffected side. The classification performance achieved 92.2% accuracy with two PCCs, 94.1% with four PCCs and 96.1% with six PCCs. Four subjects reached normal boundary after treatment, with all FGA subjects presenting decreased D. This study demonstrates that PCA is an adequate method for discriminating normal and abnormal gait and D allows an objective evaluation of the progress and effectiveness of rehabilitation treatment.     

An appraisal of CT pulmonary density mapping in normal subjects

Modern computed tomographic (CT) scanners have post-processing facilities which allow pixels within a selected density range to be highlighted. It has been suggested that using this technique to highlight regions of low CT density (-900H to -1000H) can locate and quantitate areas of pulmonary emphysema. To establish the variability of the lung density map in normal subjects this technique was used in 17 patients with no evidence of structural lung disease on full respiratory function testing. Mean CT lung density varied from -770H to -875H (overall mean -817H). The percentage cross-sectional area in the low density range -900H to -1000H varied from 0.6% to 58% (mean 15.3%). In two further groups of 12 subjects the influence of CT slice thickness and intravenous contrast administration on the lung density map was evaluated. The use of narrower collimation led to an increase in mean cross-sectional area within the low density range from 9.6% to 16.1% (P less than 0.05). The use of intravenous contrast led to a reduction in mean cross-sectional area within the range from 8.9% to 3.3% (P less than 0.01). There is considerable variability in the lung density map of normal individuals and the method is also dependent on radiographic technique. These factors should be taken into account when considering the use of CT lung density mapping for the assessment of pulmonary disease.     

Assessment of brain core temperature using MR DWI-thermometry in Alzheimer disease patients compared to healthy subjects

Purpose

To assess the brain core temperature of Alzheimer disease (AD) patients in comparison with healthy volunteers using diffusion-weighted thermometry.

Materials and methods

Fourteen AD patients (3 men, 11 women; age range 60–81 years, mean age 73.8 ± 6.1 years) and 14 healthy volunteers, age and sex-matched (mean age 70.1 ± 6.9 years; range 62–84 years; 5 men, 9 women) underwent MR examination between February 2014 and March 2016. MR imaging studies were performed with a 1.5-T MR scanner. Brain core temperature (T: °C) was calculated using the following equation from the diffusion coefficient (D) in the lateral ventricular (LV) cerebrospinal fluid: T = 2256.74/ln (4.39221/D) ? 273.15 using a standard DWI single-shot echo-planar pulse sequence (b value 1000 s/mm²). Statistical analysis was performed using a nonparametric Wilcoxon rank-sum test to compare the patient and control groups regarding LV temperatures.

Results

There was no significant difference (P = 0.1937) in LV temperature between patients (mean 37.9 ± 1.1 °C, range 35.8–39.2 °C) and control group (38.7 ± 1.4 °C, range 36.9–42.7 °C).

Conclusions

Brain core temperature in AD patients showed no significant alterations compared to healthy volunteers.

     

Ornithine metabolism in normal subjects and patients with cancer

The metabolism of L-(1-14C)ornithine monohydrochloride was monitored in patients with histologically proven cancer and in normal volunteers. Following i.v. injection of 8 microCi C-14 ornithine (160 nmoles), the decarboxylation of ornithine--yielding 14CO2--was monitored for a 2.5-hr period using the ionization chamber and vibrating-reed electrometer of Tolbert, as modified by Davidson and Schwabe. Twelve normal subjects exhaled 7.3-15.7% of the administered C-14 (mean 12.6% s.d. 3.11%). In ten patients tested before initiation of therapy, recovery ranged from 18.2-32.1% (mean 23.02%, s.d. 4.52%). A t-test indicates a confidence level of > 99.5% that a significant difference exists between the two means. Re-testing of two normal volunteers showed little or no change in ornithine metabolism over a 2-5-mo period. Results from testing three cancer patients before and after therapy correlate well with clinical evidence of the presence of tumor burden.     

Recurrence quantification analysis of gait in normal and hypovestibular subjects

The study of postural control processes during locomotion may provide useful outcome measures of stability for people with unilateral vestibular hypofunction (UVH). Since nonlinear analysis techniques can characterize complex behaviour of a system, this may highlight mechanisms underlying dynamic stability in locomotion, although only few efforts have been made. In particular, there have been no studies that use recurrence quantification analysis (RQA), which can be applied even to short and non-stationary data. The purpose of this study was to develop a new method for walking balance assessment measuring the complexity of head, trunk and pelvis three-dimensional accelerations and angular velocities during normal overground locomotion by means of RQA in normal subjects and UVH patients. The results showed differential effect of upper body parts on pattern regularity, with better head than pelvis stabilization in both groups of subjects. The RQA outputs such as percent determinism and recurrence were nevertheless significantly lower in the UVH group for all measures, suggesting that body accelerations and angular velocities, although not significantly different in amplitude, were more chaotic in patients. The observed lower regularity of upper body movements in UVH is consistent with an important role of the vestibular system in controlling dynamic stability during walking. The findings suggest that RQA can be used as a quantitative tool to assess walking performance and rehabilitation outcome in patients with different balance disorders.     

Functional relationship between the cerebrum and cerebellum in normal subjects

To determine whether a functional relationship between the cerebrum and cerebellum exists in normal subjects, the correlation between asymmetry in cerebral blood flow and asymmetry in cerebellar blood flow was investigated. Twenty-one healthy right-handed subjects were studied using SPECT with N-isopropyl-p-(123I)iodoamphetamine while in a resting state. The asymmetry index (AI) for both the cerebral and cerebellar hemisphere was calculated as follows. AI = R - L/R + L/200 (%) (R: right side, L: left side). A negative correlation was found between AI in the cerebellum and AI in cerebrum. Especially, AI in cerebellar hemisphere was significantly correlated with AIs in the upper frontal cortex (r = -0.58, p less than 0.01), middle frontal cortex (r = -0.55, p less than 0.02), lower frontal cortex (r = -0.49, p less than 0.05), and mean cerebral hemisphere (r = -0.52, p less than 0.02). These results suggest the existence of a functional relationship between the cerebral hemisphere and the contralateral cerebellar hemisphere in the resting state of normal subjects. We strongly suspect that the frontal cortex exert an influence on the function in the contralateral cerebellum, probably due to a transneuronal mechanism, mainly through the corticopontocerebellar pathway.     

Clinical outcome and imaging follow-up in acute stroke patients with normal perfusion CT and normal CT angiography

Introduction  

Acute stroke multimodal CT imaging (MMCT: non-enhanced CT, CT angiography, and CT perfusion (CTP)) may show normal results despite persistent clinical stroke. We prospectively evaluated the sensitivity/specificity of MMCT infarct detection and the clinical outcome in patients with normal MMCT findings.     

Phalangeal US velocity discriminates between normal and vertebrally fractured subjects

The purpose of this study was to evaluate the diagnostic sensitivity of phalangeal bone ultrasound velocity of the hand in the diagnosis of osteoporosis and to compare this technique to bone mineral density (BMD) measurement at the lumbar spine assessed by dual X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). We investigated US velocity at the distal metaphysis of the proximal phalanx and spinal BMD in 101 women. Fifty-nine were healthy (mean age 50 ± 11.6 years) and 42 were osteoporotic (mean age 65 ± 6.6 years) with documented vertebral fractures. In the healthy population the relation with age was, respectively, r = –0.73 (p < 0.0001) for quantitative US (QUS), r = –0.74 (p < 0.0001) for QCT and r = –0.48 (p < 0.01) for DXA. Both US and DXA were correlated with QCT: r = 0.74 and r = 0.77 (p < 0.0001), respectively. Correlation of QUS and DXA was r = 0.56 (p < 0.0001). Phalangeal US velocity and spinal BMD (QCT and DXA) values discriminate healthy from osteoporotic women. Age-adjusted logistic regression analysis of the data showed standardized odds ratios (OR) for vertebral fracture to be similar for US and DXA (OR = 1.8 and 1.5, respectively) and stronger for QCT (OR = 2.9). Phalangeal US velocity reflects age-related bone loss and differentiates between healthy and osteoporotic subjects. Received: 28 August 1998; Revision received: 24 December 1998; Accepted: 28 December 1998     

CT density of mesenteric, retroperitoneal, and subcutaneous fat in cirrhotic patients: comparison with control subjects

We determined the density in Hounsfield units of the mesenteric, retroperitoneal, and subcutaneous fat on CT scans made in 41 patients with biopsy-proved cirrhosis and compared the results with the density of the fat in these locations in 34 control subjects, in an attempt to quantify changes in fat density in patients with cirrhosis. The mean densities of mesenteric, retroperitoneal, and subcutaneous fat in patients with cirrhosis were -56, -107, and -111 H, respectively. The corresponding mean densities in control subjects were -107, -118, and -124 H. The mean density of mesenteric fat in patients with cirrhosis was 50% greater than that of their subcutaneous fat (p less than .0001), 48% greater than that of their retroperitoneal fat (p less than .0001), and 48% greater than that of the mesenteric fat in control subjects (p less than .0001). The mean density of subcutaneous fat in the anterior abdominal wall in patients with cirrhosis was -96 H compared with -119 H for that in their posterior abdominal wall. The corresponding mean densities in control subjects were -109 and -131 H. Density of subcutaneous fat in the anterior abdominal wall for all subjects (patients and controls) was 18% greater than that of subcutaneous fat in the posterior abdominal wall (p less than .05). In all locations, the statistical trend was for patients with cirrhosis to have higher density fat than did control subjects. These changes in density are thought to represent diffuse fat edema, most prominently in the mesentery because of portal hypertension.     

正常和异常胰腺的CT征象分析

目的通过对正常胰腺组和异常胰腺组CT表现的比较分析,提高对正常和异常胰腺CT征象的认识.材料与方法使用Philips公司的Tomoscan-CX-Q型全身CT机,对患者行上腹部的平扫及增强扫描.正常组有120例,异常组65例.结果CT清晰显示胰腺的大小、形态、位置,并可显示胰实质的密度及造影增强情况,还可以显示胰管、胰周情况.胰腺的异常CT征象为胰腺体积增大、肿块、胰周脂肪层次不清及增强后胰腺内低密度影等.结论CT对胰腺病变定性诊断有较大的价值.     

Hair analysis does not allow to discriminate between acute and chronic administrations of a drug in young children

There are many differences between the hair from children and that of adult subjects, the hair being thinner, more porous with a different growth rate from the usual 1 cm/month observed in adults. In order to determine whether hair analysis could discriminate between chronic use and acute administration of a drug in children like in adults, we analyzed hair from 18 children aged between 1 day and 15 years in whom the administration of different drugs was known (single therapeutic administration or acute intoxication). A strand of hair was sampled within 1 to 45 days after treatment or intoxication. Analysis was conducted using LC/MS/MS. In the 10 youngest children, aged between 1 day and 29 months, the compounds administered in hospital or responsible for intoxication (lidocaine, ropivacaine, diazepam, midazolam, levetiracetam, morphine, ketamine, methadone, buprenorphine, THC, MDMA) were found in all segments of the hair independently of the time of sampling (1–45 days after ingestion). The concentrations detected were similar along the hair shaft, showing a radial diffusion and incorporation of the analytes in the hair of young children from the sebum. Concentrations could be very high when sampled shortly after administration (72 ng/mg for methadone, 75 ng/mg for MDMA after 3 days) and lower when sampling later (1.2 ng/mg for MDMA after 45 days). In these cases, hair analysis allowed to highlight the compounds responsible for intoxication even when they had disappeared from the blood or urine but should not be used to discriminate long-term exposure to a drug. In the eight remaining children aged from 34 months to 15 years, the drugs used in hospital (lidocaine, diazepam, morphine) or responsible for intoxication (THC, codeine, buprenorphine) were not found in any analyzed segments sampled 1 to 5 days after administration of the drugs, in agreement with the non-incorporation of the drugs from the sebum into the hair. For those children aged over 34 months, hair analysis allows to determine the chronic administration of a drug, like in adults.

     

Use of automated image registration to generate mean brain SPECT image of Alzheimer’s patients

The purpose of this study was to compute and compare the group mean HMPAO brain SPECT images of patients with senile dementia of Alzheimer’s type (SDAT) and age matched control subjects after transformation of the individual images to a standard size and shape.Methods: Ten patients with Alzheimer’s disease (age 71.6 ± 5.0 yr) and ten age matched normal subjects (age 71.0 ± 6.1 yr) participated in this study. Tc-99m HMPAO brain SPECT and X-ray CT scans were acquired for each subject. SPECT images were normalized to an average activity of 100 counts/pixel. Individual brain images were transformed to a standard size and shape with the help of Automated Image Registration (AIR). Realigned brain SPECT images of both groups were used to generate mean and standard deviation images by arithmetic operations on voxel based numerical values. Mean images of both groups were compared by applying the unpaired t-test on a voxel by voxel basis to generate three dimensional T-maps. X-ray CT images of individual subjects were evaluated by means of a computer program for brain atrophy.Results: A significant decrease in relative radioisotope (RI) uptake was present in the bilateral superior and inferior parietal lobules (p < 0.05), bilateral inferior temporal gyri, and the bilateral superior and middle frontal gyri (p < 0.001). The mean brain atrophy indices for patients and normal subjects were 0.853 ± 0.042 and 0.933 ± 0.017 respectively, the difference being statistically significant (p < 0.001).Conclusion: The use of a brain image standardization procedure increases the accuracy of voxel based group comparisons. Thus, intersubject averaging enhances the capacity for detection of abnormalities in functional brain images by minimizing the influence of individual variation.