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PubMed1987

Event-related cross-correlations between spike trains illustrated on interactions between motor units and muscle spindle afferents.

A method is presented for computing correlation coefficients of two (or more) output spike trains in temporal relation to one (or more) input even trains. These event-related correlation functions are computed by convolving the output spike trains, represented as point processes, with rectangular pulses of selectable width, and by then calculating linear correlation coefficients for the pairs of amplitude values obtained from the two convolved processes in temporal relation to the input events. The merits of this technique are illustrated on stimulus trains delivered to motor units (MUs) and output spike trains recorded from muscle spindle afferents of the same cat hindlimb muscle. The correlation functions obtained show the temporal course of the correlated firings of the two afferents (mostly Ia afferents from primary muscle spindle endings) as a function of time from MU activation; they are compared with the conventional cross-correlation histograms (CCHs) between afferents and with peri-stimulus time histograms (PSTHs) between stimulus and afferent firing patterns. Stimulus-related cross-correlation functions as displayed here can be calculated for any three spike trains. Possible extensions of the method to larger numbers of input and output channels are also discussed.

Action Potentials↗

PubMed1995

Cross-correlation of bilateral differences in fatigue during sustained maximal voluntary contraction.

Maximal isometric force and electromyograph (EMG) activity of biceps brachii muscle during bilateral sustained elbow flexion were followed in 25 right-handed oarsmen. The percentage decline in force was greater for the left than for the right arm. Also, the mean power frequency (MPF) and the root mean square (rms) value of the EMG amplitude decreased more for the left than for the right arm. It was hypothesized that a "common drive" would indicate that the two forces curves would be highly correlated during the nonfatigued period, but the level of cross-correlation would decline during muscle fatigue. For the first 4 s of the contraction, the cross-correlation between the right and left force was high (r = 0.99), but thereafter it declined rapidly to a constant level. The decline of the cross-correlation was accompanied by a similar decrease in the correlation between the right and left EMG activations (MPF and rms). Thus, the decline in the cross-correlation level of force accompanied by a similar decrease in the correlation level of EMG would suggest a fatigue-induced neural derangement of the common drive.

Adult↗

PubMed1992

Correlation of cervicovaginal fluid volume with serum estradiol levels and total follicular volume during human gonadotropin stimulation.

During the normal menstrual cycle the volume of cervicovaginal fluid (CVF), as determined by the patient at home using a simple volumetric aspirating pipette, increases significantly over several days prior to the luteinizing hormone (LH) surge and decreases characteristically shortly after ovulation. The present study was undertaken to test the hypothesis that self-determined measurements of CVF volume would correlate positively with serum estradiol (E2) levels and with total follicular volume (TFV) in cycles stimulated with exogenous gonadotropins. Consequently, 20 infertility patients, undergoing human menopausal gonadotropin (hMG)-stimulated cycles, were asked to measure daily CVF. Routine serum E2 determinations and vaginal follicular ultrasound studies were performed up to and including the day of human chorionic gonadotropin (hCG) administration (designated day 0). The mean daily CVF volume (+/- SD) increased from 0.1 +/- 0.01 ml on day -6 to 0.7 +/- 0.40 ml on day -1 and then decreased to 0.6 +/- 0.40 ml on day 0. On day 0, 7 of 20 cycles (35%) demonstrated a decrease in CVF, which ranged from 0.1 to 1.0 ml (mean, 0.42 ml). The mean daily CVF correlated positively (correlation coefficient = r) with the mean daily serum E2 (r = 0.89) and with the mean daily TFV (r = 0.88). The mean daily correlation of TFV for E2 was r = 0.98. The correlation between CVF and E2 of individuals ranged from r = 0.38 to r = 0.99 and the correlation between CVF and TFV ranged from r = 0.12 to r = 1.0, while the individual correlations of E2 to TFV ranged from r = 0.60 to r = 0.99.(ABSTRACT TRUNCATED AT 250 WORDS)

Cervix Mucus↗

PubMed1997

P300 topography of amplitude/latency correlations.

The correlational association from 19 electrode sites between peak amplitude and latency for the P3(00) event-related brain potential (ERP) for n = 80 homogeneous subjects was assessed using a simple auditory discrimination task. The correlation strength varied systematically across scalp topography in different ways for the various ERP components. For the target stimuli, P3 amplitude and latency were negatively correlated and most tightly coupled over the frontal-central and right medial/lateral recording sites. In contrast, the N1 produced negative correlations that were strongest over the left and right central/lateral locations; P2 demonstrated a positive correlation that was strongest frontally and centrally; N2 demonstrated a positive correlations that was strongest over the central and parietal sites. ERPs from the standard stimuli produced generally similar patterns for the P3 and P2 components, with only weak or no reliable effects observed for the N1 and N2 potentials. Taken together, the findings suggest that analysis of amplitude/latency correlational relationships can provide information about ERP component generation. Theoretical implications are discussed.

Adult↗

PubMedDate not supplied

Granule cell mRNA levels for BDNF, NGF, and NT-3 correlate with neuron losses or supragranular mossy fiber sprouting in the chronically damaged and epileptic human hippocampus.

This study determined in temporal lobe epilepsy patients if there were correlations among hippocampal granule cell expression of neurotrophin mRNAs, aberrant supragranular mossy fiber sprouting, and neuron losses. Consecutive surgically resected hippocampi (n = 9) and comparison tissue from autopsies (n = 3) were studied for: 1. Granule cell mRNA levels using in situ hybridization for brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and neurotrophin-3 (NT-3); 2. neo-Timm supragranular mossy fiber sprouting; and 3. Ammon's horn neuron densities. Clinically, patients were classified into those with hippocampal sclerosis (HS; n = 7) and non-HS cases (i.e., mass lesions and autopsies; n = 5). Results showed that compared to non-HS cases, HS patients showed increased granule cell mRNA levels for BDNF, NGF, and NT-3 (p = 0.035, p = 0.04, p = 0.045 respectively; one-tail directional test). Moreover, granule cell BDNF mRNA levels correlated inversely with Ammon's horn neuron densities (p = 0.02) and correlated positively with greater supragranular mossy fiber sprouting (p = 0.02). NGF mRNA levels correlated inversely with Ammon's horn neuron densities (p = 0.02), and NT-3 mRNA levels correlated inversely with age at surgery (p = 0.04) and correlated positively with greater mossy fiber sprouting (p = 0.026). These results indicate in the chronically damaged human hippocampus that granule cells express neurotrophin mRNAs, and mRNA levels correlate with either hippocampal neuron losses or aberrant supragranular mossy fiber sprouting. These data support the hypothesis that in the epileptic human hippocampus, there may be pathophysiologic associations among mossy fiber synaptic plasticity, hippocampal neuron damage, and granule cell mRNA neurotrophin levels.

Analysis of Variance↗

PubMed1997

Correlations among bone mineral density, broadband ultrasound attenuation, mechanical indentation testing, and bone orientation in bovine femoral neck samples.

Broadband ultrasound attenuation (BUA) of the calcaneus has been found to correlate with bone mineral density (BMD) of the femoral neck. The purpose of this study was to determine if a correlation exists among femoral neck BUA, femoral neck BMD, and incremental indent depth, a qualitative indicator of local mechanical bone strength, in bovine samples, and if this correlation is dependent upon orientation. For 12 of the bovine samples obtained, BUA was measured at the femoral neck and was followed by a BMD determination of the same area. A 19 mm diameter bicortical core containing the center of the area of interest was removed, transversely cut into 7 mm, thick disks, and tested for hardness by indent depth. For these tests, BMD was well correlated with BUA (R2 = 0.85, P < 0.001). An inversely proportional relationship with a modest correlation was found between indent depth and BMD (R2 = 0.59, P = 0.026), and indent depth and BUA (R2 = 0.57, P = 0.031). In a second set of tests involving 15 different bovine samples, a bicortical core was removed from the femoral neck. A trabecular bone cube measuring 1.5 cm on a side was removed from the center of the core. BUA and BMD measurements were made along the anterior-posterior (AP), medial-lateral (ML), and cephalic-caudal (CC) aspects of the cube. The cubes were randomly separated into three groups, cut in half perpendicular to the axis of interest, and tested for hardness by indent depth. In these tests, no significant difference was found in BMD among the three orientations of the cubes scanned (P = 0.77). In contrast, the BUA along the ML orientation of the cube was significantly greater than that along the AP orientation (P < 0.05). No significant difference was found in the incremental indent depth measurements among cube orientations (P = 0.41). In the test involving only trabecular bone, a much higher correlation between BMD and incremental indent depth was found regardless of cube orientation (R2 = 0.64, P < 0.001). The data indicate that BUA, but not BMD, is affected by trabecular orientation, and that BMD is negatively correlated with incremental indent depth.

Animals↗

PubMed2005

Quantification of magnetization transfer rate and native T1 relaxation time of the brain: correlation with magnetization transfer ratio measurements in patients with multiple sclerosis.

The purpose of this paper is to perform quantitative measurements of the magnetization transfer rate (Kfor) and native T1 relaxation time (T1free) in the brain tissue of normal individuals and patients with multiple sclerosis (MS) by means of multiple gradient echo acquisitions, and to correlate these measurements with the magnetization transfer ratio (MTR). Quantitative magnetization transfer imaging was performed in five normal volunteers and 12 patients with relapsing-remitting MS on a 1.5 T magnetic resonance (MR) scanner. The T1 relaxation time under magnetization transfer irradiation (T1sat) was calculated by means of fitting the signal intensity over the flip angle in several 3D spoiled gradient echo acquisitions (3 degrees , 15 degrees , 30 degrees , and 60 degrees ), while a single acquisition without MT irradiation (flip angle of 3 degrees ) was utilized to calculate the MTR. The Kfor and T1free constants were quantified on a pixel-by-pixel basis and parametric maps were reconstructed. We performed 226 measurements of Kfor, T1free, and the MTR on normal white matter (NWM) of healthy volunteers (n=50), and normal-appearing white matter (NAWM) and pathological brain areas of MS patients (n=120 and 56, respectively). Correlation coefficients between Kfor-MTR, T1free-MTR, and T1free-Kfor were calculated. Lesions were classified, according to their characteristics on T1-weighted images, into isointense (compared to white matter), mildly hypointense (showing signal intensity lower than white matter and higher than gray matter), and severely hypointense (revealing signal intensity lower than gray matter). "Dirty" white matter (DWM) corresponded to areas with diffused high signal, as identified on T2-weighted images. Strong correlation coefficients were obtained between MTR and Kfor for all lesions studied (r2=0.9, p<0.0001), for mildly hypointense plaques (r2=0.82, p<0.0001), and for DWM (r2=0.78, p=0.0007). In contrast, comparison between MTR and T1free values yielded rather low correlation coefficients for all groups assessed. In severely hypointense lesions, an excellent correlation was found between Kfor and T1free measurements (r2=0.98, p<0.0001). Strong correlations between Kfor and T1free were found for the rest of the subgroups, except for the NAWM, in which a moderate correlation was obtained (r2=0.5, p<0.0001). We conclude that Kfor and T1free measurements are feasible and may improve our understanding of the pathological brain changes that occur in MS patients.

Adult↗

PubMed2000

Atrophy of the corpus callosum correlates with white matter lesions in patients with cerebral ischaemia.

Many studies of white matter high signal (WMHS) on T2-weighted MRI have disclosed that it is related to cerebral ischaemia and to brain atrophy. Atrophy of the corpus callosum (CC) has also been studied in relation to ischaemia. Our objective was to test the hypothesis that CC atrophy could be due to ischaemia. We therefore assessed CC, WMHS and brain atrophy in patients with risk factors without strokes (the risk factor group) and in those with infarcts (the infarct group), to investigate the relationships between these factors. We studied 30 patients in the infarct group, 14 in the risk factor group, and 29 normal subjects. Using axial T1-weighted MRI, cortical atrophy and ventricular enlargement (brain atrophy) were visually rated. Using axial T2-weighted MRI, WMHS was assessed in three categories: periventricular symmetrical, periventricular asymmetrical and subcortical. Using the mid-sagittal T1-weighted image, the CC was measured in its anterior, posterior, mid-anterior and mid-posterior portions. In the normal group, no correlations were noted between parameters. In the infarct group, there were significant correlations between CC and brain atrophy, and between CC atrophy and WMHS. After removing the effects of age, gender and brain atrophy, significant correlations were noted between some CC measures and subcortical WMHS. In the risk factor group, there were significant correlations between CC and brain atrophy and between CC atrophy and WMHS. After allowance for age, gender and brain atrophy, significant correlations between some CC measures and periventricular WMHS remained. The hypothesis that CC atrophy could be due to cerebral ischaemia was supported by other analyses. Namely, for correlations between the extent of infarcts and partial CC atrophy in patients with anterior middle cerebral artery (MCA) and with posterior MCA infarcts, there were significant correlations between the extent of infarct and mid-anterior CC atrophy in the former, and posterior CC atrophy in the latter. Our findings could indicate that CC atrophy is associated with cerebral ischaemia.

Adult↗

PubMed2001

The correlation between 99mTc-MIBI uptake and MIB-1 as a nuclear proliferation marker in glioma--a comparative study with 201Tl.

Technetium-99m methoxy-isobutylisonitrile (MIBI), like thallium-201 (201Tl), is a highly efficient agent for the diagnosis and monitoring of glioma tumors. Although 201Tl uptake is known to be partly associated with proliferative activity, little is known about the correlation between MIBI uptake and proliferation activity in gliomas. The current study was performed to assess the correlation between MIBI uptake and proliferative activities in gliomas, estimated by the monoclonal antibody to Ki-67 antigen (MIB-1) staining method. By comparing the results with those of 201Tl, we determined which tracer would be suitable for estimating proliferative activities. Twenty-four presurgical glioma patients (six with low-grade gliomas, five with anaplastic astrocytomas, and 13 with glioblastomas) were given MIBI and 201Tl SPECT. Early (10 min after injection) and delayed images (3 h after injection) were obtained for both MIBI and 201Tl scintigraphy. SPECT parameters, early ratio (ER), delayed ratio (DR), and retention index (RI) were obtained in both radiopharmaceuticals. All patients underwent subsequent surgical excision, and the specimens were immunostained for MIB-1. The proliferative activity was measured as a percentage positive nuclear area for MIB-1 (MI; MIB-1 index). To evaluate the relationship between the proliferative activity and SPECT parameters, we performed a correlation analysis. MI correlated with the MIBI uptake ratio (r = 0.75 for ER, and r = 0.7 for DR). Both DR and RI of 201Tl also correlated with MI, but weakly (r = 0.6 for DR, and. r = 0.59 for RI). There was no significant correlation between the MIB-1 index and the other parameters. MIBI-uptake parameters demonstrated a stronger positive correlation with the MIB-1 index than that of 201Tl. With the use of MIBI SPECT, we can estimate the proliferative activity of glioma noninvasively.

Adolescent↗

PubMed1998

Correlation of dynamic contrast-enhanced magnetic resonance imaging with histologic tumor grade: comparison of macromolecular and small-molecular contrast media.

BACKGROUND: The endothelial integrity of microvessels is disrupted in malignant tumors. Quantitative assays of tumor microvascular characteristics based on dynamic magnetic resonance imaging (MRI) were correlated with histopathologic grade in mammary soft tissue tumors. MATERIALS AND METHODS: A spectrum of tumors, benign through highly malignant, was induced in 33 female rats by administration of N -ethyl-N -nitrosourea (ENU), a potent carcinogen. Dynamic contrast-enhanced MRI was performed using a small-molecular contrast medium [gadopentetate, MW = 0.5 kDa] and a macromolecular contrast medium [albumin-(Gd-DTPA)30, MW = 92 kDa] at an interval of 1-2 days. Permeability surface area product (PS), as estimated by the corresponding endothelial transfer coefficient (KPS), and fractional plasma volume (fPV) were calculated for each tumor and each contrast agent using a two-compartment bi-directional kinetic model. MRI microvascular characteristics were correlated with histopathologic tumor grade. RESULTS: Tumor permeability to macromolecular contrast medium, characterized by KPS, showed a highly positive correlation with tumor grade (r 2 = 0.76, P < 10(-10)). KPS values were zero for all benign and some low-grade carcinomas, greater than zero in all other carcinomas, and increased in magnitude with higher tumor grade. A considerably smaller but significantly positive correlation was found between fPV and tumor grade using macromolecular contrast medium (r 2 = 0.25, P < 0.003). No correlation between KPS or fPV values and tumor grade was found using gadopentetate (r 2 = 0.01, P > 0.95 and r2 = 0.03, P > 0.15, respectively). CONCLUSION: Quantitative tumor microvascular permeability assays generated with macromolecular MRI contrast medium correlate closely with histologic tumor grade. No significant correlation is found using small-molecular gadopentetate.

Albumins↗

PubMed2004

Adductor-related groin pain in athletes: correlation of MR imaging with clinical findings.

OBJECTIVE: To evaluate gadolinium-enhanced MR imaging in athletes with chronic groin pain and correlate with the clinical features. DESIGN AND PATIENTS: MR examinations performed in 52 athletes (51 male, 1 female; median age 26 years) with chronic groin pain and 6 asymptomatic control athletes (6 male; median age 29 years) were independently reviewed by two radiologists masked to the clinical details. Symptom duration (median 6 months) and clinical side of severity were recorded. Anatomical areas in the pelvis were scored for abnormality (as normal, mildly abnormal or abnormal) and an overall assessment for side distribution of abnormality was recorded, initially without post-gadolinium sequences and then, 3 weeks later (median 29 days), the post-gadolinium sequences only. Correlation between radiological and clinical abnormality was calculated by Spearman's correlation. RESULTS: Abnormal anterior pubis and enthesis enhancement significantly correlated with clinical side for both radiologists (both P=0.008). Abnormal anterior pubis and adductor longus enthesis oedema was significant for one radiologist ( P=0.009). All other features showed no significant correlation ( P>0.05). In the control cases there was no soft tissue abnormality but symphyseal irregularity was present ( n=2). For both radiologists assessment of imaging side severity significantly correlated with clinical side for post-gadolinium ( P=0.048 and P=0.023) but not non-gadolinium sequences ( P>0.05). CONCLUSION: The extent and side of anterior pubis and adductor longus enthesis abnormality on MR imaging significantly and reproducibly correlates with the athletes' current symptoms in chronic adductor-related groin pain.

Adolescent↗

PubMedDate not supplied

Expression of vascular endothelial growth factor in hepatocellular carcinoma and the surrounding liver: correlation with MR imaging and angiographically assisted CT.

We summarize and discuss our previous research results on the correlation between findings on magnetic resonance (MR) imaging and angiographically assisted computed tomography (CT) and the intensity of vascular endothelial growth factor (VEGF) expression in hepatocellular carcinoma (HCC) and in the surrounding nontumorous liver. MR images (n = 22), CT during arterial portography (n = 20), and CT hepatic arteriography (n = 17) were retrospectively correlated quantitatively and qualitatively with VEGF expression in HCCs and in the surrounding liver assessed by western blotting. HCC-to-liver contrast-to-noise ratio correlated with VEGF expression index (VEGF(IND)) values of HCCs inversely on opposed-phase, T1-weighted, spoiled gradient recalled-echo (GRE) images, directly on T2-weighted, fast spin-echo images, and marginally and inversely on gadolinium-enhanced hepatic arterial-phase GRE images. On T2-weighted fast spin-echo images, standard deviation ratio of HCCs correlated directly with VEGF(IND) values of HCCs. By CT hepatic arteriography, the contrast-enhancement index of HCCs showed a moderate inverse correlation with VEGF(IND) values of HCCs, and the contrast-enhancement index of the liver showed marginal, moderate direct correlation with VEGF(IND) values in the liver. Heterogeneities of HCCs on images correlated directly with VEGF(IND) values of HCCs on opposed-phase T1-weighted GRE images, T2-weighted fast spin-echo images, hepatic arterial-phase GRE images, equilibrium-phase GRE images, and CT hepatic arteriogram. Our results may reflect that MR signal intensity, hepatic arterial vascularity, and heterogeneity of HCCs on CT or MR images are closely related to the intensity of VEGF expression in HCC as upregulated by hyper- or hypoxia in HCCs. Although the real effects of our results on radiologic practice are debatable at this moment, we believe that our results may help future radiologic practice in conjunction with biomolecular or genetic treatment for HCCs.

Carcinoma, Hepatocellular↗

PubMed1997

Serum levels of interleukin-1 beta, luteinizing hormone, and prolactin correlate with the expression of CD45 isoforms on CD4+ peripheral blood T lymphocytes in healthy women.

The expected association between age and the CD45 isoforms expression on CD4+ T-PBL is much more obvious in men than in women. We investigated whether or not circulating factors influence the differentiation of CD4+ T-PBL. Peripheral blood samples were obtained from 56 healthy age-matched subjects (28 men and 28 women, 21-55 years old). Mononuclear leukocytes were analyzed by three-color flow cytometry. The serum concentrations of interleukin-1 beta (IL-1 beta), interleukin-6, tumor necrosis factor-alpha (TNF-alpha), GM colony-stimulating factor, prolactin (Prl), and luteinizing hormone (LH) were determined by ELISA. The expected age-related decrease of naive (CD45RA+,RO-) cells and increase of memory (CD45RA-,RO+) cells among CD4+ T-PBL were observed in men only (p < 0.001 and 0.005). In women, these correlations were not significant. On the other hand, in women only, elevated IL-1 beta was associated with fewer naive and more memory cells among CD4+ T-PBL (p < 0.001). In both sexes, IL-1 beta correlated with the expression of CD25 on CD4+ T-PBL (on either naive or memory cells, p < 0.001). Other cytokines or the CD8+ T-PBL showed no significant correlation. In women, the elevation of LH at mid-cycle inversely correlated with the proportion of naive CD4+ T-PBL (p < 0.01). Elevated LH was associated with more CD25 on memory CD4+ T-PBL (p < 0.01). A significant correlation exists between IL-1 beta and LH (p < 0.001). Furthermore, in both sexes, Prl correlated with the proportion of CD4+ cells among T-PBL. In men, elevated Prl was associated with more naive CD4+ T-PBL (p < 0.005), while in women, Prl correlated with more transient CD45RA+, RO+ cells among CD4+ T-PBL and increased TNF-alpha (p < 0.05 for both). Thus, circulating IL-1 beta could be involved in the expression of CD25 on CD4+ T-PBL and favors the generation of memory CD4+ T-PBL. In women, the IL-1 beta- and/or mid-cycle-dependent processes seem to overwhelm the age-related changes. Elevated Prl might exert a dual influence: it favors the development of naive CD4+ T lymphocytes and possibly acts in, synergy with other cytokines during immune stimulation.

Adult↗

PubMed2002

Circulating interleukin-6, soluble interleukin-2 receptors, tumor necrosis factor alpha, and interleukin-10 levels in juvenile chronic arthritis: correlations with soft tissue vascularity assessed by power Doppler sonography.

Nineteen patients with juvenile chronic arthritis (JCA), ten with systemic (s)-JCA, and nine with polyarticular-onset (p)-JCA were examined for interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, IL-2R, and IL-10 levels. Power Doppler sonography (PDS) for the more affected knee was used in all of them to evaluate soft tissue vascularity. Serum levels of IL-6 were significantly higher in JCA patients than in controls (P<0.007). Patients with p-JCA showed higher levels of IL-6 than patients with s-JCA, and the difference was statistically nonsignificant. Serum IL-6 levels in all patients correlated significantly with the degree of vascularity detected by PDS (P<0.01). This correlation was more pronounced in p-JCA patients (P<0.01 in p-JCA vs P<0.05 in s-JCA). Serum levels of TNF-alpha were higher in patients with JCA than in controls (P<0.0001). Serum levels of TNF-alpha were significantly greater in patients with s-JCA than in p-JCA (P=0.008). Soluble IL-2R levels were higher in patients with JCA than controls (P<0.0002). Serum levels of IL-2R correlated significantly with pannus thickness in p-JCA (P<0.01) and inversely with methoxetrate (MTX) duration in s-JCA (P<0.05). Serum levels of IL-10 were significantly higher in JCA patients than in controls ( P<0.0008). Serum IL-10 levels in all patients correlated significantly inversely with hemoglobin levels (r=-0.50, P<0.05), total leukocytic count (TLC) (r=-0.58, P<0.01), and intra-articular steroid injection (r=+0.56, P<0.01). In s-JCA, IL-10 levels correlated significantly with MTX weekly dose ( P<0.05). In conclusion, a significant correlation of serum IL-6 levels with the degree of knee joint vascularity was found, and this correlation was more pronounced in p-JCA, which may stress the role of IL-6 as an inducer of neoangiogenesis in JCA.

Adolescent↗

PubMed2003

T2 relaxation time analysis in patients with multiple sclerosis: correlation with magnetization transfer ratio.

The aim of the current study was to perform T2 relaxation time measurements in multiple sclerosis (MS) patients and correlate them with magnetization transfer ratio (MTR) measurements, in order to investigate in more detail the various histopathological changes that occur in lesions and normal-appearing white matter (NAWM). A total number of 291 measurements of MTR and T2 relaxation times were performed in 13 MS patients and 10 age-matched healthy volunteers. Measurements concerned MS plaques (105), NAWM (80), and "dirty" white matter (DWM; 30), evenly divided between the MS patients, and normal white matter (NWM; 76) in the healthy volunteers. Biexponential T2 relaxation-time analysis was performed, and also possible linearity between MTR and mean T2 relaxation times was evaluated using linear regression analysis in all subgroups. Biexponential relaxation was more pronounced in "black-hole" lesions (16.6%) and homogeneous enhancing plaques (10%), whereas DWM, NAWM, and mildly hypointense lesions presented biexponential behavior with a lower frequency(6.6, 5, and 3.1%, respectively). Non-enhancing isointense lesions and normal white matter did not reveal any biexponential behavior. Linear regression analysis between monoexponential T2 relaxation time and MTR measurements demonstrated excellent correlation for DWM( r=-0.78, p<0.0001), very good correlation for black-hole lesions( r=-0.71, p=0.002), good correlation for isointense lesions( r=-0.60, p=0.005), moderate correlation for mildly hypointense lesions( r=-0.34, p=0.007), and non-significant correlation for homogeneous enhancing plaques, NAWM, and NWM. Biexponential T2 relaxation-time behavior is seen in only very few lesions (mainly on plaques with high degree of demyelination and axonal loss). A strong correlation between MTR and monoexponential T2 values was found in regions where either inflammation or demyelination predominates; however, when both pathological conditions coexist, this linear relationship is lost.

Adolescent↗

PubMed1997

Correlation of pudendal nerve terminal motor latency with the results of anal manometry.

UNLABELLED: Denervation to the external anal sphincter is commonly found in disordered defaecation. AIM: To determine whether a correlation exists between pudendal nerve terminal motor latency (PNTML) and anal manometry and what influence an external sphincter defect (ESD) has on any correlation. METHOD: Sixty seven consecutive patients (23 constipated, 44 incontinent) were analysed. All had results available for PNTML and anal manometry. Anal ultrasound performed in the later part of the study period was available in 46 patients. RESULTS: A significant negative correlation was found between the mean PNTML and squeeze pressures (SP) for incontinent patients (r = -0.32, P = 0.037). No significant correlation was seen in constipated patients. A coexisting ESD was found in 57% of the 46 patients studied. In those without an ESD a significant negative correlation was found between mean PNTML and SP (r = -0.50; P = 0.026). No correlation was found in patients with an ESD. Age did not significantly affect the PNTML or SP results, but was associated with a reduced resting pressure (r = -0.34; P = 0.005). CONCLUSIONS: The PNTML was significantly correlated with SP in patients with incontinence and in the subgroup of patients without an ESD. In the assessment of disordered defaecation PNTML is therefore recommended as an adjunct to anal ultrasound.

Adolescent↗

PubMed2002

Monitoring retinal function in neovascular maculopathy using multifocal electroretinography - early and long-term correlation with clinical findings.

PURPOSE: To objectively investigate and longitudinally monitor retinal function in patients with choroidal neovascularization (CNV) due to exudative age-related macular degeneration (AMD) and myopia using multifocal electroretinography (mfERG). METHODS: Patients with classic and occult subfoveal CNV secondary either to AMD or to myopia were enrolled in the study. The mfERGs were performed at the beginning of the study and every 3 months subsequently during a follow-up period of 15 months. In addition, standardized visual acuity testing, ophthalmologic examinations, color fundus photographs and fluorescein angiography were performed. The mfERG records were derived with the VERIS-System (Electro-Diagnostic Imaging, San Mateo, Calif., USA); 103 locations within the central 50 degrees in diameter were stimulated concurrently by means of the m-sequence technique. Fixation stability was monitored throughout the recording session with an infrared eye monitoring system (VERIS Refractor/Camera unit). The first-order response component was extracted for each stimulated retinal location. The response densities of the first-order kernel were evaluated as a function of eccentricity from the center (ring 1) to the periphery of the stimulated area (ring 6). The results were compared to those derived from age-matched normal control groups. For each patient mfERG responses measured on follow-up visits were compared to each other to evaluate and monitor changes in retinal function. These changes were tested for correlation with those observed in other clinical and electroretinographic findings. Statistical analysis was performed using the Pearson coefficient. RESULTS: Subfoveal neovascular maculopathy was associated with a reduction in response density most prominent within the central 5 degrees over the area affected by CNV detected either at the beginning of the study or at the follow-up recordings. During the follow-up period patients 1 and 4 showed stabilization or a slight increase in response densities over the neovascular lesion-complex and a corresponding stabilization or slight increase in visual acuity accompanied by a decrease in the activity of the neovascular lesion as determined by fluorescein angiography. Patient 2 revealed an increase in response density correlating with an increase in visual acuity and decrease in lesion size. In the contralateral eye of this patient the response density dropped in the area of new subfoveal CNV. In patient 3 continuous progression of the disease was documented by fluorescein angiography and visual acuity. It correlated well with a continuous decrease in retinal response densities during the follow-up. CONCLUSIONS: Objective monitoring of retinal function and correlation with morphological and psychophysical findings was at least in part possible in patients suffering from AMD and myopia. In all of four patients whose subfoveal CNV was documented by fluorescein angiography. Response densities were reduced particularly in the central 5 degrees and in visual acuity. The mfERG data showed a moderate to high statistical correlation with visual function as measured by visual acuity. On the other hand, the greatest linear dimension of the lesion size showed only a weak to moderate statistical correlation with both the response densities of the mfERG and the visual acuity. We conclude that the size of the CNV complex does not represent an accurate measure of retinal function in neovascular maculopathy. The good correlation of the mfERG data with visual acuity suggests that it may serve for objective assessment of retinal function, of the areas overlying the CNV. It shows potential as a valuable tool for longitudinal monitoring of AMD patients.

Aged↗

PubMed2006

Effect of grid laser photocoagulation in diffuse diabetic macular edema in correlation to glycosylated haemoglobin (HbA1c).

BACKGROUND: Glycosylated haemoglobin (HbA1c) correlates with the amount of hyperglycemia in diabetic patients. High HbA1c levels often predict clinically significant macular edema (CSME), which then needs to be treated with grid laser photocoagulation. The question asked in this study was whether there is a correlation between the effect grid laser photocoagulation in diffuse diabetic macular edema and HbA1c, using an optical coherence tomography (OCT) for the evaluation of the retinal thickness. METHODS: A prospective, non-comparative case series was performed to find a correlation between the effect of grid laser photocoagulation in diffuse diabetic macular edema and HbA1c. Thirty eyes with CSME of diabetic patients were included in the study. Complete ophthalmic examinations and OCT were performed at baseline, 1 month, 3, and 6 months after grid laser photocoagulation therapy. HbA1c was measured at the end of study. RESULTS: Significance level was set at P<0.05. A significant difference in the foveal (P=0.02) and superior (P=0.021) retinal thickness 6 months after laser therapy, no correlation between HbA1c and retinal thickness after photocoagulation, and an insignificant decrease in visual acuity (P=0.9) were found. The correlation between foveal retinal thickness and visual acuity was P=0.24 6 months after treatment. CONCLUSION: There was no significant correlation between HbA1c and the effect of grid laser photocoagulation therapy in diffuse diabetic macular edema. The retinal thickness decreased significantly in the foveal and superior area 6 months after therapy. No correlation between the foveal retinal thickness and the visual acuity was found. The visual acuity did not increase after treatment. There are many factors influencing the retinal thickness, such as the blood pressure and the attached posterior hyaloid.

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