ECG signal quality in intermittent long-term dry electrode recordings with controlled motion artifacts.

Wearable long-term monitoring applications are becoming more and more popular in both the consumer and the medical market. In wearable ECG monitoring, the data quality depends on the properties of the electrodes and on how they interface with the skin. Dry electrodes do not require any action from the user. They usually do not irritate the skin, and they provide sufficiently high-quality data for ECG monitoring purposes during low-intensity user activity. We investigated prospective motion artifact-resistant dry electrode materials for wearable ECG monitoring. The tested materials were (1) porous: conductive polymer, conductive silver fabric; and (2) solid: stainless steel, silver, and platinum. ECG was acquired from test subjects in a 10-min continuous settling test and in a 48-h intermittent long-term test. In the settling test, the electrodes were stationary, whereas both stationary and controlled motion artifact tests were included in the long-term test. The signal-to-noise ratio (SNR) was used as the figure of merit to quantify the results. Skin-electrode interface impedance was measured to quantify its effect on the ECG, as well as to leverage the dry electrode ECG amplifier design. The SNR of all electrode types increased during the settling test. In the long-term test, the SNR was generally elevated further. The introduction of electrode movement reduced the SNR markedly. Solid electrodes had a higher SNR and lower skin-electrode impedance than porous electrodes. In the stationary testing, stainless steel showed the highest SNR, followed by platinum, silver, conductive polymer, and conductive fabric. In the movement testing, the order was platinum, stainless steel, silver, conductive polymer, and conductive fabric.

Technical Performance Assessment and Quality Control of Ultrasound Device Monitors.

The purpose of this study was to investigate and evaluate the current technical performance of ultrasound imaging device displays. Altogether 53 ultrasound device displays were evaluated in two hospital districts of Finland. The performance of the displays was evaluated with tests and test patterns developed by American Association of Physicists in Medicine (AAPM). Minimum, maximum and ambient luminances (Lmin,Lmax,Lamb) were measured. Ambient ratio (AR), luminance ratio (LR), [Formula: see text] and [Formula: see text] were calculated, and luminance uniformity, defined as deviation from the median (MLD), was evaluated. The results indicate that none of the measured displays fulfill the AAPM Task Group (TG) 270 maximum luminance recommendation for diagnostic displays. A majority (32/53, 60%) of the displays fail the AAPM TG270 acceptable level for secondary displays as well. Only 3 of 53 (6%) displays were at the acceptable level for diagnostic displays. Also, for most of the displays (41/53, 77%), [Formula: see text] was under the diagnostic acceptable level. Ambient ratios exceeded the acceptable limit in 31 of 53 (58%) displays. Luminance ratios, on the other hand, were within acceptable levels for the majority of displays (38/53, 72%). All devices passed the AAPM requirement for luminance uniformity (MLD). The results indicate that the maximum luminance and minimum luminance of most displays are not sufficient. AAPM, the Society for Imaging Informatics in Medicine and the American College of Radiology introduced the updated luminance [Formula: see text] and [Formula: see text] criteria in 2012. All ultrasound displays should at least fulfill the AAPM TG18 secondary display minimum criteria. Even so, 6 of 53 (11%) fail. The newest displays should be expected to fulfill the revised AAPM TG270 criteria as well. Display technology has developed, and therefore, monitor testing needs to be updated.

Reliability of the freehand region-of-interest method in quantitative cerebral diffusion tensor imaging.

BACKGROUND: Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique used for evaluating changes in the white matter in brain parenchyma. The reliability of quantitative DTI analysis is influenced by several factors, such as the imaging protocol, pre-processing and post-processing methods, and selected diffusion parameters. The region-of-interest (ROI) method is most widely used of the post-processing methods because it is found in commercial software. The focus of our research was to study the reliability of the freehand ROI method using various intra- and inter-observer analyses. METHODS: This study included 40 neurologically healthy participants who underwent diffusion MRI of the brain with a 3 T scanner. The measurements were performed at nine different anatomical locations using a freehand ROI method. The data extracted from the ROIs included the regional mean values, intra- and inter-observer variability and reliability. The used DTI parameters were fractional anisotropy (FA), the apparent diffusion coefficient (ADC), and axial (AD) and radial (RD) diffusivity. RESULTS: The average intra-class correlation coefficient (ICC) of the intra-observer was found to be 0.9 (excellent). The single ICC results were excellent (> 0.8) or adequate (> 0.69) in eight out of the nine regions in terms of FA and ADC. The most reliable results were found in the frontobasal regions. Significant differences between age groups were also found in the frontobasal regions. Specifically, the FA and AD values were significantly higher and the RD values lower in the youngest age group (18-30 years) compared to the other age groups. CONCLUSIONS: The quantitative freehand ROI method can be considered highly reliable for the average ICC and mostly adequate for the single ICC. The freehand method is suitable for research work with a well-experienced observer. Measurements should be performed at least twice in the same region to ensure that the results are sufficiently reliable. In our study, reliability was slightly undermined by artifacts in some regions such as the cerebral peduncle and centrum semiovale. From a clinical point of view, the results are most reliable in adults under the age of 30, when age-related changes in brain white matter have not yet occurred.

VASIM: an automated tool for the quantification of carotid atherosclerosis by computed tomography angiography.

The diagnostic imaging techniques currently used to evaluate the arterial atherosclerosis hinge on the manual marking and calculation of the stenosis degree. However, the manual assessment is highly dependent on the operator and characterized by low replicability. The study aimed to develop a fully-automated tool for the segmentation and analysis of atherosclerosis in the extracranial carotid arteries. The dataset consisted of 59 randomly-chosen individuals who had undergone head-and-neck computed tomography angiography (CTA), at the Tampere University Hospital, Tampere, Finland. The analysis algorithm was mainly based on the detection of carotid arteries, delineation of the vascular wall, and extraction of the atherosclerotic plaque. To improve the vascular detection rate, the model-based and volume-wide analytical approaches were deployed. A new fully-automated vascular imaging (VASIM) software tool was developed. For stenosis over 50%, the success rate was 83% for the detection and segmentation. Specificity and sensitivity of the algorithm were 25% and 83%, respectively. The overall accuracy was 71%. The VASIM tool is the first published approach for the fully-automated analysis of atherosclerosis in extracranial carotid arteries. The tool provides new outputs, which may help with the quantitative and qualitative, clinical evaluation of the atherosclerosis burden and evolution. The findings from this study provide a basis for the further development of automated atherosclerosis diagnosis and plaque analysis with CTA.

99mTc-Sestamibi/123I Subtraction SPECT/CT in Parathyroid Scintigraphy: Is Additional Pinhole Imaging Useful?

OBJECTIVES: This retrospective study evaluated whether the use of additional anterior 99mTc-sestamibi/123I pinhole imaging improves the outcome of 99mTc-sestamibi/123I subtraction SPECT/CT in parathyroid scintigraphy (PS). MATERIALS AND METHODS: PS using simultaneous dual-isotope subtraction methods and an acquisition protocol combining SPECT/CT and planar pinhole imaging was performed for 175 patients with primary or secondary hyperparathyroidism. All patients who proceeded to surgery with complete postsurgery laboratory findings were included in this study (n = 94). SPECT/CT images alone and combined with pinhole images were evaluated. RESULTS: There were 111 enlarged parathyroid glands of which 104 and 108 glands were correctly visualized by SPECT/CT (seven false positives) or SPECT/CT with pinhole (three false positives), respectively. Both sensitivity and specificity were higher with combined SPECT/CT with pinhole than with SPECT/CT alone (97% versus 94% and 99% versus 98%, resp., not significant). The false-positive rate was 6% with SPECT/CT and decreased to 3% using combined SPECT/CT with pinhole. CONCLUSION: 99mTc-sestamibi/123I subtraction SPECT/CT is a highly sensitive and specific protocol for PS. The use of additional anterior pinhole imaging increases both sensitivity and specificity of PS, although this increase is not statistically significant.

Spinal cord injury induces widespread chronic changes in cerebral white matter.

Traumatic spinal cord injuries (SCIs) lead to axonal damage at the trauma site, as well as disconnections within the central nervous system. While the exact mechanisms of the long-term pathophysiological consequences of SCIs are not fully understood, it is known that neuronal damage and degeneration are not limited to the direct proximity of the trauma. Instead, the effects can be detected even in the cerebrum. We examined SCI-induced chronic brain changes with a case-control design using 32 patients and 70 control subjects. Whole-brain white matter (WM) tracts were assessed with diffusion tensor imaging (DTI). In addition, we analysed associations between DTI metrics and several clinical SCI variables. Whole-brain analyses were executed by tract-based spatial statistics (TBSS), with an additional complementary atlas-based analysis (ABA). We observed widespread, statistically significant (P ≤ 0.01) changes similar to neural degeneration in SCI patients, both in the corticospinal tract (CST) and beyond. In addition, associations between DTI metrics and time since injury were found with TBSS and ABA, implying possible long-term post-injury neural regeneration. Using the ABA approach, we observed a correlation between SCI severity and DTI metrics, indicating a decrease in WM integrity along with patient sensory or motor scores. Our results suggest a widespread neurodegenerative effect of SCI within the cerebrum that is not limited to the motor pathways. Furthermore, DTI-measured WM integrity of chronic SCI patients seemed to improve as time elapsed since injury. Hum Brain Mapp 38:3637-3647, 2017. © 2017 Wiley Periodicals, Inc.

The Association Between Liver and Tumor [18F]FDG Uptake in Patients with Diffuse Large B Cell Lymphoma During Chemotherapy.

PURPOSE: The aim of this study was to explore the association between liver, mediastinum and tumor 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) uptake during chemotherapy in diffuse large B cell lymphoma (DLBCL). PROCEDURES: Nineteen patients with proven DLBCL underwent positron emission tomography (PET)/X-ray computed tomography scan at baseline, 1 week and 2 cycles after rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) therapy, and again after chemotherapy completion. The mean and maximal standardized uptake value (SUVmean and SUVmax) of the liver and mediastinum were measured and correlated with the tumor SUVmax, SUVsum, whole-body metabolic tumor volume (MTVwb), and total lesion glycolysis (TLG). RESULTS: At baseline, both the liver and mediastinum SUVmean and SUVmax correlated inversely with the tumor MTVwb or TLG (p < 0.01 or 0.001). The liver SUVmean and SUVmax increased significantly after 1 week of R-CHOP therapy and remained at the high level until chemotherapy completion. The mediastinum SUVmean and SUVmax remained stable during chemotherapy. The tumor SUVmax, SUVsum, MTVwb, and TLG decreased significantly after 1 week of R-CHOP therapy. The change of the liver SUVmean correlated inversely with the change of tumor MTVwb and TLG after 1 week of chemotherapy (p < 0.05, respectively). The intersubject variability of liver and mediastinum [18F]FDG uptake ranged from 11 to 26 %. CONCLUSIONS: The liver [18F]FDG uptake increased significantly after R-CHOP therapy. One of the possible reasons is the distribution of a greater fraction of the tracer to healthy tissues rather than tumor after effective chemotherapy. The variability of the liver [18F]FDG uptake during chemotherapy might affect the visual analysis of the interim PET scan and this needs to be confirmed in future studies with a large patient cohort. In addition, the intersubject variability of the liver and mediastinum [18F]FDG uptake should be considered.

Automatic detection of carotid arteries in computed tomography angiography: a proof of concept protocol.

Atherosclerosis is one of the leading causes of mortality in the western world. Computed tomography angiography (CTA) is the conventional imaging method used for pre-surgery assessment of the blood flow within the carotid vessel. In this paper, we present a proof of concept of a novel, fast and operator independent protocol for the automatic detection (seeding) of the carotid arteries in CTA in the thorax and upper neck region. The dataset is composed of 14 patients' CTA images of the neck region. The performance of this method is compared with manual seeding by four trained operators. Inter-operator variation is also assessed based on the dataset. The minimum, average and maximum coefficient of variation among the operators was (0, 2, 5 %), respectively. The performance of our method is comparable with the state of the art alternative, presenting a detection rate of 75 and 71 % for the lowest and uppermost image levels, respectively. The mean processing time is 167 s per patient versus 386 s for manual seeding. There are no significant differences between the manual and automatic seed positions in the volumes (p = 0.29). A fast, operator independent protocol was developed for the automatic detection of carotid arteries in CTA. The results are encouraging and provide the basis for the creation of automatic detection and analysis tools for carotid arteries.

Differentiation of Diffuse Large B-cell Lymphoma From Follicular Lymphoma Using Texture Analysis on Conventional MR Images at 3.0 Tesla.

RATIONAL AND OBJECTIVES: Diffuse large B-cell lymphoma (DLBCL) represents the most common type of aggressive non-Hodgkin lymphoma (NHL); follicular lymphoma (FL) is the most frequent indolent NHL. The aim of this study was to investigate whether texture-based analysis of conventional magnetic resonance imaging (MRI) allows discrimination of DLBCL from FL, and further, to correlate the MRI texture features with diffusion-weighted imaging apparent diffusion coefficient (ADC) value and tumor tissue cellularity. MATERIALS AND METHODS: Forty-one patients with histologically proven NHL (30 DLBCL and 11 FL) underwent conventional MRI and diffusion-weighted imaging examination before treatment. Based on regions of interest, texture analysis was performed on T1-weighted images pre- and postcontrast enhancement and on T2-weighted images with and without fat suppression, and features derived from the run-length matrix- and co-occurrence matrix-based methods were analyzed. Receiver operating characteristic curves were performed for the three most discriminative texture features for the differentiation of the two most common types of lymphoma. The analyzed MRI texture features were correlated with the ADC value and the tumor tissue cellularity. RESULTS: We found that on T1-weighted images postcontrast enhancement, run-length matrix-based texture analysis for lesion classification differentiated DLBCL from FL, with specificity and sensitivity of 76.6% and 76.5%, respectively. There was no correlation between the texture features and the ADC value or tumor tissue cellularity. CONCLUSIONS: DLBCL and FL can be differentiated by means of texture analysis on T1-weighted MRI postcontrast enhancement. These results could serve as a basis for the use of the texture features on conventional MRI as adjunct to clinical examination to distinguish DLBCL from FL.

MR image texture in Parkinson's disease: a longitudinal study.

BACKGROUND: Few of the structural changes caused by Parkinson's disease (PD) are visible in magnetic resonance imaging (MRI) with visual inspection but there is a need for a method capable of observing the changes beyond the human eye. Texture analysis offers a technique that enables the quantification of the image gray-level patterns. PURPOSE: To investigate the value of quantitative image texture analysis method in diagnosis and follow-up of PD patients. MATERIAL AND METHODS: Twenty-six PD patients underwent MRI at baseline and after 2 years of follow-up. Four co-occurrence matrix-based texture parameters, describing the image homogeneity and complexity, were calculated within clinically interesting areas of the brain. In addition, correlations with clinical characteristics (Unified Parkinson's Disease Ranking Scales I-III and Mini-Mental State Examination score) along with a comparison to healthy controls were evaluated. RESULTS: Patients at baseline and healthy volunteers differed in their brain MR image textures mostly in the areas of substantia nigra pars compacta, dentate nucleus, and basilar pons. During the 2-year follow-up of the patients, textural differences appeared mainly in thalamus and corona radiata. Texture parameters in all the above mentioned areas were also found to be significantly related to clinical scores describing the severity of PD. CONCLUSION: Texture analysis offers a quantitative method for detecting structural changes in brain MR images. However, the protocol and repeatability of the method must be enhanced before possible clinical use.

Hemispheric asymmetry measured by texture analysis and diffusion tensor imaging in two multiple sclerosis subtypes.

BACKGROUND: This paper addresses two subtypes of multiple sclerosis (MS), primary progressive multiple sclerosis (PPMS) and relapsing-remitting multiple sclerosis (RRMS). The separation of PPMS and RRMS is challenging in certain cases. PURPOSE: To quantitatively determine MS subtypes using texture analysis (TA) and diffusion tensor imaging (DTI). MATERIAL AND METHODS: T1-weighted (T1W) magnetic resonance imaging (MRI) and DTI of the left and right brain hemispheres of 17 patients with PPMS and 19 patients with RRMS were studied. Areas of the caudate nucleus and thalamus were investigated as normal appearing gray matter (NAGM), and areas of the cerebral peduncle and centrum semiovale were investigated as normal appearing white matter (NAWM). The described locations were symmetrical and were accurately marked. TA was performed on the T1W images, and the fractional anisotropy and apparent diffusion coefficient were determined from the DTI data. RESULTS: Hemispherical differences were found with both TA and DTI. Several texture and diffusion tensor parameter values calculated for the left and right hemispheres of the patients showed statistically significant differences. The patients with RRMS had greater significant differences (P < 0.01) in the thalamus between the hemispheres than did the patients with PPMS. The TA classification accuracy of the PPMS and RRMS subtypes was above 80%. CONCLUSION: TA can be helpful when distinguishing between PPMS and RRMS, while DTI appears to reveal the hemispherical asymmetry of RRMS patients.

MRI Texture Analysis and Diffusion Tensor Imaging in Chronic Right Hemisphere Ischemic Stroke.

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) is shown to reveal changes caused by cerebral infarction. The aim of this study is to reveal those changes also in the conventional magnetic resonance (MR) images using a quantitative image analysis method, texture analysis (TA). METHODS: Thirty patients who had suffered their first ever infarction located on the right hemisphere underwent DTI and conventional MRI studies in the chronic phase. DTI parameters fractional anisotropy and mean diffusivity, as well as four second-order texture parameters were calculated. Interhemispheric differences and correlations between DTI and TA parameters were evaluated. RESULTS: Our DTI findings supported earlier studies as fractional anisotropy values were lowered and mean diffusivity values elevated in the lesion site, and ipsilateral cerebral peduncle, thalamus, and centrum semiovale compared to the unaffected side. Textural homogeneity parameters showed lower and complexity parameters higher values in the lesion site and ipsilateral centrum semiovale compared to the contralateral hemisphere. Correlation between the two methods was found in ipsilateral mesencephalon. CONCLUSIONS: In addition to DTI method, TA could assist in revealing the changes caused by infarction, also outside the lesion site. Damaged areas were found more heterogeneous and random in texture compared to unaffected sites.

Early interim PET/CT predicts post-treatment response in diffuse large B-cell lymphoma.

BACKGROUND: (18)F-FDG-PET/CT has been widely used in the staging of malignant lymphomas, and accepted as a tool for response assessment. Among PET parameters, the most frequently studied is maximal standardized uptake value (SUVmax). Metabolic tumor burden (MTB) is a parameter in which both metabolic tumor volume (MTV) and tumor activity are integrated. Here, we analyzed the prognostic value of SUVmax, SUVsum (sum of the SUVmax), whole-body MTV (MTVwb) and MTBwb from baseline and interim PET/CT in patients with diffuse large B-cell lymphoma (DLBCL). MATERIAL AND METHODS: Twenty-nine patients with histologically proven DLBCL were imaged by PET/CT before treatment (Exam I), and one week after the first dose of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) therapy (Exam II). Biopsy specimens were examined by an expert hematopathologist, the Ki-67 proliferation index (PI) was estimated for each biopsy site from the MIB-1 stained sections. The response evaluation was performed after chemotherapy completion (6-8 cycles). RESULTS: All patients had one or more visualized lymphomatous lesions on (18)F-FDG-PET/CT. The SUVmax of the whole-body (BmSUVmax) was higher than the SUVmax at biopsy site (BxSUVmax) (mean: 20.1 vs. 17.3, p < 0.01). The PI correlated with the BxSUVmax (p < 0.05). One week after chemotherapy, SUVmax, SUVsum, MTVwb, and MTBwb decreased significantly (p < 0.01, respectively), SUVsum, MTVwb and MTBwb at Exam II correlated with chemotherapy response at treatment completion (p < 0.05, respectively). CONCLUSION: SUVmax is more accurate to detect tumor aggressiveness than biopsy in DLBCL, since BmSUVmax represents the most aggressive tumor of the patient. Interim PET/CT as early as one week after R-CHOP therapy predicts response. Thus, it could be used as a tool for guidance of risk stratification in DLBCL.

Acute mild traumatic brain injury is not associated with white matter change on diffusion tensor imaging.

This study was designed to (i) evaluate the influence of age on diffusion tensor imaging measures of white matter assessed using tract-based spatial statistics; (ii) determine if mild traumatic brain injury is associated with microstructural changes in white matter, in the acute phase following injury, in a large homogenous sample that was carefully screened for pre-injury medical, psychiatric, or neurological problems; and (iii) examine if injury severity is related to white matter changes. Participants were 75 patients with acute mild traumatic brain injury (age = 37.2 ± 12.0 years, 45 males and 30 females) and 40 controls (age = 40.6 ± 12.2 yrs, 20 males and 20 females). Age effects were analysed by comparing control subgroups aged 31-40, 41-50, and 51-60 years against a group of 18-30-year-old control subjects. Widespread statistically significant areas of abnormal diffusion tensor measures were observed in older groups. Patients and controls were compared using age and gender as covariates and in age- and gender-matched subgroups. Subgroups of patients with more severe injuries were compared to age-and gender-matched controls. No significant differences were detected in patient-control or severity analyses (all P-value > 0.01). In this large, carefully screened sample, acute mild traumatic brain injury was not associated with diffusion tensor imaging abnormalities detectable with tract-based spatial statistics.

A semi-automatic segmentation method for the structural analysis of carotid atherosclerotic plaques by computed tomography angiography.

AIM: Computed tomography angiography (CTA) is currently the most reliable imaging technique for evaluating and planning the treatment of atherosclerosis. The drawbacks of the technique are its low spatial resolution and challenging manual measurements. The purpose of this study was to develop a semi-automatic method to segment vessel walls, surrounding tissue, and the carotid artery lumen to measure the severity of stenosis. METHODS: In vivo contrast CTA images from eight patients undergoing endarterectomy were analyzed using a tailored five-step process involving an adaptive segmentation algorithm and region growing to measure the maximum percent stenosis in the cross-sectional area of the carotid artery. The accuracy of this method was compared with that of manual measurements made by physicians. RESULTS: There were no significant differences between the maximum percent stenosis value obtained using the semi-automatic tool and that obtained using manual measurements (6%; p=0.31). The data acquisition and analysis required an average of 145 seconds. CONCLUSION: This new semi-automatic segmentation method for CTA provides a fast and reliable tool to quantify the severity of carotid artery stenosis.

Correlations between functional imaging markers derived from PET/CT and diffusion-weighted MRI in diffuse large B-cell lymphoma and follicular lymphoma.

OBJECTIVES: To investigate the correlations between functional imaging markers derived from positron emission tomography/computed tomography (PET/CT) and diffusion-weighted magnetic resonance imaging (DWI) in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). Further to compare the usefulness of these tumor markers in differentiating diagnosis of the two common types of Non-Hodgkin's lymphoma (NHL). MATERIALS AND METHODS: Thirty-four consecutive pre-therapy adult patients with proven NHL (23 DLBCL and 11 FL) underwent PET/CT and MRI examinations and laboratory tests. The maximum standardized uptake value (SUV(max)), metabolic tumor volume (MTV), and metabolic tumor burden (MTB) were determined from the PET/CT images. DWI was performed in addition to conventional MRI sequences using two b values (0 and 800 s/mm(2)). The minimum and mean apparent diffusion coefficient (ADC(min) and ADC(mean)) were measured on the parametric ADC maps. RESULTS: The SUV(max) correlated inversely with the ADC(min) (r =  -0.35, p<0.05). The ADC(min), ADC(mean), serum thymidine kinase (TK), Beta 2-microglobulin (B2m), lactate dehydrogenase (LD), and C-reactive protein (CRP) correlated with both whole-body MTV and whole-body MTB (p<0.05 or 0.01). The SUV(max), TK, LD, and CRP were significantly higher in the DLBCL group than in the FL group. Receiver operating characteristic curve analysis showed that they were reasonable predictors in differentiating DLBCL from FL. CONCLUSIONS: The functional imaging markers determined from PET/CT and DWI are associated, and the SUV(max) is superior to the ADC(min) in differentiating DLBCL from FL. All the measured serum markers are associated with functional imaging markers. Serum LD, TK, and CRP are useful in differentiating DLBCL from FL.

Influence of exercise loading on magnetic resonance image texture of thigh soft tissues.

Adaptation to exercise training can affect bone marrow adiposity; muscle-fat distribution; and muscle volume, strength and architecture. The objective of this study was to identify exercise-load-associated differences in magnetic resonance image textures of thigh soft tissues between various athlete groups and non-athletes. Ninety female athletes representing five differently loading sport types (high impact, odd impact, high magnitude, repetitive low impact and repetitive non-impact), and 20 non-athletic clinically healthy female controls underwent magnetic resonance imaging. Five thigh muscles, subcutaneous fat and femoral bone marrow were analysed with co-occurrence matrix-based quantitative texture analysis at two anatomical levels of the dominant leg. Compared with the controls thigh muscle textures differed especially in high-impact and odd-impact exercise-loading groups. However, all sports appeared to modulate muscle textures to some extent. Fat tissue was found different among the low-impact group, and bone marrow was different in the high-impact group when compared to the controls. Exercise loading was associated with textural variation in magnetic resonance images of thigh soft tissues. Texture analysis proved a potential method for detecting apparent structural differences in the muscle, fat and bone marrow.

3D texture analysis reveals imperceptible MRI textural alterations in the thalamus and putamen in progressive myoclonic epilepsy type 1, EPM1.

Progressive myoclonic epilepsy type 1 (EPM1) is an autosomal recessively inherited neurodegenerative disorder characterized by young onset age, myoclonus and tonic-clonic epileptic seizures. At the time of diagnosis, the visual assessment of the brain MRI is usually normal, with no major changes found later. Therefore, we utilized texture analysis (TA) to characterize and classify the underlying properties of the affected brain tissue by means of 3D texture features. Sixteen genetically verified patients with EPM1 and 16 healthy controls were included in the study. TA was performed upon 3D volumes of interest that were placed bilaterally in the thalamus, amygdala, hippocampus, caudate nucleus and putamen. Compared to the healthy controls, EPM1 patients had significant textural differences especially in the thalamus and right putamen. The most significantly differing texture features included parameters that measure the complexity and heterogeneity of the tissue, such as the co-occurrence matrix-based entropy and angular second moment, and also the run-length matrix-based parameters of gray-level non-uniformity, short run emphasis and long run emphasis. This study demonstrates the usability of 3D TA for extracting additional information from MR images. Textural alterations which suggest complex, coarse and heterogeneous appearance were found bilaterally in the thalamus, supporting the previous literature on thalamic pathology in EPM1. The observed putamenal involvement is a novel finding. Our results encourage further studies on the clinical applications, feasibility, reproducibility and reliability of 3D TA.

Comparison of different MRI sequences in lesion detection and early response evaluation of diffuse large B-cell lymphoma--a whole-body MRI and diffusion-weighted imaging study.

To compare different MRI sequences for the detection of lesions and the evaluation of response to chemotherapy in patients with diffuse large B-cell lymphoma (DLBCL), 18 patients with histology-confirmed DLBCL underwent 3-T MRI scanning prior to and 1 week after chemotherapy. The MRI sequences included T1-weighted pre- and post-contrast, T2 -weighted with and without fat suppression, and a single-shot echo-planar diffusion-weighted imaging (DWI) with two b values (0 and 800 s/mm(2)). Conventional MRI sequence comparisons were performed using the contrast ratio between tumor and normal vertebral body instead of signal intensity. The apparent diffusion coefficient (ADC) of the tumor was measured directly on the parametric ADC map. The tumor volume was used as a reference for the evaluation of chemotherapy response. The mean tumor volume was 374 mL at baseline, and decreased by 65% 1 week after chemotherapy (p < 0.01). The T2 -weighted image with fat suppression showed a significantly higher contrast ratio compared with images from all other conventional MRI sequences, both before and after treatment (p < 0.01, respectively). The contrast ratio of the T2 -weighted image with fat suppression decreased significantly (p < 0.01), and that of the T1 -weighted pre-contrast image increased significantly (p < 0.01), after treatment. However, there was no correlation between the change in contrast ratio and tumor volume. The mean ADC value was 0.68 × 10(-3) mm(2)/s at baseline; it increased by 89% after chemotherapy (p < 0.001), and the change in ADC value correlated with the change in tumor volume (r = 0.66, p < 0.01). The baseline ADC value also correlated inversely with the percentage change in ADC after treatment (r = -0.62, p < 0.01). In conclusion, this study indicates that T2-weighted imaging with fat suppression is the best conventional sequence for the detection of lesions and evaluation of the efficacy of chemotherapy in DLBCL. DWI with ADC mapping is an imaging modality with both diagnostic and prognostic value that could complement conventional MRI.

Comparison of five parathyroid scintigraphic protocols.

Objectives. We compared five parathyroid scintigraphy protocols in patients with primary (pHPT) and secondary hyperparathyroidism (sHPT) and studied the interobserver agreement. The dual-tracer method ((99m)Tc-sestamibi/(123)I) was used with three acquisition techniques (parallel-hole planar, pinhole planar, and SPECT/CT). The single-tracer method ((99m)Tc-sestamibi) was used with two acquisition techniques (double-phase parallel-hole planar, and SPECT/CT). Thus five protocols were used, resulting in five sets of images. Materials and Methods. Image sets of 51 patients were retrospectively graded by four experienced nuclear medicine physicians. The final study group consisted of 24 patients (21 pHPT, 3 sHPT) who had been operated upon. Surgical and histopathologic findings were used as the standard of comparison. Results. Thirty abnormal parathyroid glands were found in 24 patients. The sensitivities of the dual-tracer method (76.7-80.0%) were similar (P = 1.0). The sensitivities of the single-tracer method (13.3-31.6%) were similar (P = 0.625). All differences in sensitivity between these two methods were statistically significant (P < 0.012). The interobserver agreement was good. Conclusion. This study indicates that any dual-tracer protocol with (99m)Tc-sestamibi and (123)I is superior for enlarged parathyroid gland localization when compared with single-tracer protocols using (99m)Tc-sestamibi alone. The parathyroid scintigraphy was found to be independent of the reporter.