Region Of Interest Values Research Articles

Inter- and intra-rater reliability of diffusion tensor imaging parameters in the normal pediatric spinal cord.

To assess inter- and intra-rater reliability (agreement) between two region of interest (ROI) methods in pediatric spinal cord diffusion tensor imaging (DTI). Inner-Field-of-View DTI data previously acquired from ten pediatric healthy subjects (mean age = 12.10 years) was used to assess for reliability. ROIs were drawn by two neuroradiologists on each subject data twice within a 3-mo interval. ROIs were placed on axial B0 maps along the cervical spine using free-hand and fixed-size ROIs. Agreement analyses for fractional anisotropy (FA), axial diffusivity, radial diffusivity and mean diffusivity were performed using intra-class-correlation (ICC) and Cronbach's alpha statistical methods. Inter- and intra-rater agreement between the two ROI methods showed moderate (ICC = 0.5) to strong (ICC = 0.84). There were significant differences between raters in the number of pixels selected using free-hand ROIs (P < 0.05). However, no significant differences were observed in DTI parameter values. FA showed highest variability in ICC values (0.10-0.87). Cronbach's alpha showed moderate-high values for raters and ROI methods. The study showed that high reproducibility in spinal cord DTI can be achieved, and demonstrated the importance of setting detailed methodology for post-processing DTI data, specifically the placement of ROIs.

Computer-Aided Diagnosis for Preoperative Invasion Depth of Gastric Cancer with Dual-Energy Spectral CT Imaging

This study evaluates the accuracy of dual-energy spectral computed tomography (DEsCT) imaging with the aid of computer-aided diagnosis (CAD) system in assessing serosal invasion in patients with gastric cancer. Thirty patients with gastric cancer were enrolled in this study. Two types of features (information) were collected with the use of DEsCT imaging: conventional features including patient's clinical information (eg, age, gender) and descriptive characteristics on the CT images (eg, location of the lesion, wall thickness at the gastric cardia) and additional spectral CT features extracted from monochromatic images (eg, 60keV) and material-decomposition images (eg, iodine- and water-density images). The classification results of the CAD system were compared to pathologic findings. Important features can be found out using support vector machine classification method in combination with feature-selection technique thereby helping the radiologists diagnose better. Statistical analysis showed that for the collected cases, the feature "long axis" was significantly different between group A (serosa negative) and group B (serosa positive) (P < .05). By adding quantitative spectral features from several regions of interest (ROIs), the total classification accuracy was improved from 83.33% to 90.00%. Two feature ranking algorithms were used in the CAD scheme to derive the top-ranked features. The results demonstrated that low single-energy (approximately 60keV) CT values, tumor size (long axis and short axis), iodine (water) density, and Effective-Z values of ROIs were important for classification. These findings concurred with the experience of the radiologist. The CAD system designed using machine-learning algorithms may be used to improve the identification accuracy in the assessment of serosal invasion in patients of gastric cancer with DEsCT imaging and provide some indicators which may be useful in predicting prognosis.

Simple and Efficient Method for Region of Interest Value Extraction from Picture Archiving and Communication System Viewer with Optical Character Recognition Software and Macro Program

The objectives are: 1) to introduce a simple and efficient method for extracting region of interest (ROI) values from a Picture Archiving and Communication System (PACS) viewer using optical character recognition (OCR) software and a macro program, and 2) to evaluate the accuracy of this method with a PACS workstation. This module was designed to extract the ROI values on the images of the PACS, and created as a development tool by using open-source OCR software and an open-source macro program. The principal processes are as follows: (1) capture a region of the ROI values as a graphic file for OCR, (2) recognize the text from the captured image by OCR software, (3) perform error-correction, (4) extract the values including area, average, standard deviation, max, and min values from the text, (5) reformat the values into temporary strings with tabs, and (6) paste the temporary strings into the spreadsheet. This principal process was repeated for the number of ROIs. The accuracy of this module was evaluated on 1040 recognitions from 280 randomly selected ROIs of the magnetic resonance images. The input times of ROIs were compared between conventional manual method and this extraction module-assisted input method. The module for extracting ROI values operated successfully using the OCR and macro programs. The values of the area, average, standard deviation, maximum, and minimum could be recognized and error-corrected with AutoHotkey-coded module. The average inputtimes using the conventional method and the proposed module-assisted method were 34.97 seconds and 7.87 seconds, respectively. A simple and efficient method for ROI value extraction was developed with open-source OCR and a macro program. Accurate inputs of various numbers from ROIs can be extracted with this module. The proposed module could be applied to the next generation of PACS or existing PACS that have not yet been upgraded.

The measurement of bone mineral density of bilateral proximal humeri using DXA in patients with unilateral rotator cuff tear.

We propose that the measurement of the bone mineral density (BMD) of the proximal humerus be standardized using the dual energy X-ray absorptiometry (DXA) in patients supposed to undergo rotator cuff repair surgery as well as those with the fracture of the proximal humerus as the BMD of the proximal humerus is decreased in these patients. We propose that the measurement of the BMD of the proximal humerus be standardized using the DXA in patients who are supposed to undergo rotator cuff repair surgery as well as those with the fracture of the proximal humerus. We conducted the prospective study in 213 patients with unilateral rotator cuff tear but without contralateral shoulder pain or disease. In these patients, we preoperatively measured the BMD of the bilateral proximal humeri with a repeat measurement in 20 patients. We predefined three regions of interest (ROIs) in the proximal humerus with the consideration of the rotator cuff repair surgery as well as proximal humeral fractures. The measurement of the BMD of the proximal humerus using the DXA showed excellent reliability (intraclass correlation coefficient > .90). BMD values of all three ROIs in the affected shoulder were significantly lower than those in asymptomatic shoulder (all p < 0.05). In female patients, the BMD values of ROIs in bilateral shoulder were significantly lower than those in male patients (all p < 0.001). In multiple regressions, however, there were no significant correlations between other clinical characteristics, except for the gender, and the BMD of GT in the affected shoulder. It is imperative that the bone quality of the proximal humerus be accurately evaluated prior to surgery in patients who are supposed to undergo rotator cuff repair using suture anchors as well as in those with proximal humeral fractures. This is because the BMD of the proximal humerus is decreased in these patients.

Measurement of tumor blood flow in head and neck squamous cell carcinoma by pseudo‐continuous arterial spin labeling: Comparison with dynamic contrast‐enhanced MRI

To investigate the feasibility of tumor blood flow (TBF) measurement in head and neck squamous cell carcinoma (HNSCC) using pseudo-continuous arterial spin labeling (pCASL) in a comparison with dynamic contrast-enhanced (DCE) perfusion. We prospectively scanned 18 patients with HNSCC using 3T magnetic resonance imaging (MRI) with both pCASL and DCE perfusion. Quantitative TBF value in the whole-tumor region of interest (ROI), and regional TBF in the ROIs of the central and peripheral areas in the tumor were respectively measured. Relative TBF value in the whole-tumor ROI was also calculated. We determined the correlation and agreement between each measured TBF by pCASL and DCE perfusion using Pearson's correlation coefficients, intraclass correlation coefficients (ICC), and Bland-Altman analysis. In the whole-tumor ROIs, significant correlation was observed between the absolute TBF values (r = 0.72, P < 0.01), with an ICC of 0.72; moreover, higher correlation was observed in the relative TBF (r = 0.79). The correlation was higher in the peripheral ROI (r = 0.70) than the central ROI (r = 0.65), with an ICC of 0.62 and 0.54, respectively. Bland-Altman plots revealed the underestimation of TBF by pCASL in central ROIs. TBF measurement by pCASL was feasible in patients with HNSCC.

Alignment does not influence cartilage T2 in asymptomatic knee joints

To investigate whether the static knee alignment affects articular cartilage ultrastructures when measured using T2 relaxation among asymptomatic subjects. Both knee joints (n = 96) of 48 asymptomatic volunteers (26 females, 22 males; 25.4 ± 1.7 years; no history of major knee trauma or surgery) were evaluated clinically (Lysholm, Tegner) and by MRI (hip-knee-ankle angle, standard knee protocol, T2 mapping). Group (n = 4) division was as follows: neutral (<1° varus/valgus), mild varus (2°-4° varus), severe varus (>4° varus) and valgus (2°-4° valgus) deformity with n = 12 subjects/group; n = 24 knees/group. Regions of interest (ROI) for T2 assessment were placed within full-thickness cartilage across the whole joint surface and were divided respecting compartmental as well as functional joint anatomy. Leg alignment was 0.7° ± 0.5° varus among neutral, 3.0° ± 0.6° varus among mild varus, 5.0° ± 1.1° varus among severe varus and 2.5° ± 0.7° valgus among valgus group subjects and thus significantly different. No differences between the groups emerged from clinical measures. No morphological pathology was detected in any knee joint. Global T2 values (42.3 ± 2.3; 37.7-47.9 ms) of ROIs placed within every knee joint per subject were not different between alignment groups or between genders, respectively. Static frontal plane leg malalignment does not affect cartilage ultrastructure among young, asymptomatic individuals as measured by T2 quantitative imaging. Cross-sectional study, Level II-III.

Reduced FDG-PET brain metabolism and executive function predict clinical progression in elderly healthy subjects

Brain changes reminiscent of Alzheimer disease (AD) have been previously reported in a substantial portion of elderly cognitive healthy (HC) subjects. The major aim was to evaluate the accuracy of MRI assessed regional gray matter (GM) volume, 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), and neuropsychological test scores to identify those HC subjects who subsequently convert to mild cognitive impairment (MCI) or AD dementia. We obtained in 54 healthy control (HC) subjects a priori defined region of interest (ROI) values of medial temporal and parietal FDG-PET and medial temporal GM volume. In logistic regression analyses, these ROI values were tested together with neuropsychological test scores (free recall, trail making test B (TMT-B)) as predictors of HC conversion during a clinical follow-up between 3 and 4 years. In voxel-based analyses, FDG-PET and MRI GM maps were compared between HC converters and HC non-converters. Out of the 54 HC subjects, 11 subjects converted to MCI or AD dementia. Lower FDG-PET ROI values were associated with higher likelihood of conversion (p = 0.004), with the area under the curve (AUC) yielding 82.0% (95% CI = (95.5%, 68.5%)). The GM volume ROI was not a significant predictor (p = 0.07). TMT-B but not the free recall tests were a significant predictor (AUC = 71% (95% CI = 50.4%, 91.7%)). For the combination of FDG-PET and TMT-B, the AUC was 93.4% (sensitivity = 82%, specificity = 93%). Voxel-based group comparison showed reduced FDG-PET metabolism within the temporo-parietal and prefrontal cortex in HC converters. In conclusion, medial temporal and-parietal FDG-PET and executive function show a clinically acceptable accuracy for predicting clinical progression in elderly HC subjects.

The effect of the Oxford uncemented medial compartment arthroplasty on the bone mineral density and content of the proximal tibia

We studied the bone mineral density (BMD) and the bone mineral content (BMC) of the proximal tibia in patients with a well-functioning uncemented Oxford medial compartment arthroplasty using the Lunar iDXA bone densitometer. Our hypothesis was that there would be decreased BMD and BMC adjacent to the tibial base plate and increased BMD and BMC at the tip of the keel. There were 79 consecutive patients (33 men, 46 women) with a mean age of 65 years (44 to 84) with a minimum two-year follow-up (mean 2.6 years (2.0 to 5.0)) after unilateral arthroplasty, who were scanned using a validated standard protocol where seven regions of interest (ROI) were examined and compared with the contralateral normal knee. All had well-functioning knees with a mean Oxford knee score of 43 (14 to 48) and mean Knee Society function score of 90 (20 to 100), showing a correlation with the increasing scores and higher BMC and BMD values in ROI 2 in the non-implanted knee relative to the implanted knee (p = 0.013 and p = 0.015, respectively). The absolute and percentage changes in BMD and BMC were decreased in all ROIs in the implanted knee compared with the non-implanted knee, but this did not reach statistical significance. Bone loss was markedly less than reported losses with total knee replacement. There was no significant association with side, although there was a tendency for the BMC to decrease with age in men. The BMC was less in the implanted side relative to the non-implanted side in men compared with women in ROI 2 (p = 0.027), ROI 3 (p = 0.049) and ROI 4 (p = 0.029). The uncemented Oxford medial compartment arthroplasty appears to allow relative preservation of the BMC and BMD of the proximal tibia, suggesting that the implant acts more physiologically than total knee replacement. Peri-prosthetic bone loss is an important factor in assessing long-term implant stability and survival, and the results of this study are encouraging for the long-term outcome of this arthroplasty.

The effects of exposure to 915 MHz radiofrequency identification on cerebral glucose metabolism in rat: A [F-18] FDG micro-PET study

Purpose: We investigated the effect of whole-body exposure to 915-MHz radiofrequency identification (RFID) on rat cortical glucose metabolism by using 18F-deoxyglucose positron emission tomography (FDG-PET).Materials and methods: Male Sprague-Dawley rats were divided into three groups: Cage-control, sham-exposed and RFID-exposed groups. Rats were exposed to the 915-MHz RFID for 8 h daily, 5 days per week, for 2 or 16 weeks. The whole-body average specific absorption rate (SAR) was 4 W/kg for the field of the 915 MHz RFID signal. FDG-PET images were obtained the day after RFID exposure, using micro-PET with a FDG tracer. With a Xeleris functional imaging workstation, absolute values in regions of interest (ROI) in the frontal, temporal and parietal cortexes and cerebellum were measured. Cortical ROI values were normalized to the cerebellar value and compared.Results: The data showed that the relative cerebral glucose metabolic rate was unchanged in the frontal, temporal and parietal cortexes of the 915 MHz RFID-exposed rats, compared with rats in cage-control and sham-exposed groups.Conclusion: Our results suggest that 915 MHz RFID radiation exposure did not cause a significant long lasting effect on glucose metabolism in the rat brain.

MRI of Neuronal Recovery after Low-Dose Methamphetamine Treatment of Traumatic Brain Injury in Rats

We assessed the effects of low dose methamphetamine treatment of traumatic brain injury (TBI) in rats by employing MRI, immunohistology, and neurological functional tests. Young male Wistar rats were subjected to TBI using the controlled cortical impact model. The treated rats (n = 10) received an intravenous (iv) bolus dose of 0.42 mg/kg of methamphetamine at eight hours after the TBI followed by continuous iv infusion for 24 hrs. The control rats (n = 10) received the same volume of saline using the same protocol. MRI scans, including T2-weighted imaging (T2WI) and diffusion tensor imaging (DTI), were performed one day prior to TBI, and at 1 and 3 days post TBI, and then weekly for 6 weeks. The lesion volumes of TBI damaged cerebral tissue were demarcated by elevated values in T2 maps and were histologically identified by hematoxylin and eosin (H&E) staining. The fractional anisotropy (FA) values within regions-of-interest (ROI) were measured in FA maps deduced from DTI, and were directly compared with Bielschowsky’s silver and Luxol fast blue (BLFB) immunohistological staining. No therapeutic effect on lesion volumes was detected during 6 weeks after TBI. However, treatment significantly increased FA values in the recovery ROI compared with the control group at 5 and 6 weeks after TBI. Myelinated axons histologically measured using BLFB were significantly increased (p<0.001) in the treated group (25.84±1.41%) compared with the control group (17.05±2.95%). Significant correlations were detected between FA and BLFB measures in the recovery ROI (R = 0.54, p<0.02). Methamphetamine treatment significantly reduced modified neurological severity scores from 2 to 6 weeks (p<0.05) and foot-fault errors from 3 days to 6 weeks (p<0.05) after TBI. Thus, the FA data suggest that methamphetamine treatment improves white matter reorganization from 5 to 6 weeks after TBI in rats compared with saline treatment, which may contribute to the observed functional recovery.

Quantitative multiparametric MRI of ovarian cancer

PurposeTo identify parameters associated with ovarian malignancy using multiparametric quantitative magnetic resonance imaging (MRI).Materials and MethodsAfter Institutional Review Board (IRB) approval, women with ovarian masses underwent preoperative imaging with 3 T MRI. Dynamic contrast‐enhanced (DCE)‐MRI with pharmacokinetic modeling, quantitative T2 mapping, and diffusion‐weighted imaging with quantitative mapping of the water diffusion parameters were performed. Ovarian masses had one or more discreet regions of interest, categorized as cystic or solid, and histologically diagnosed as benign or malignant. Mean region of interest (ROI) values were compared between benign and malignant masses using generalized estimating equations. In addition, we compared classification accuracy for the mean ROI value to a combination of histogram characteristics (standard deviation, skewness, and kurtosis) from T2 map ROIs using logistic regression and ROC curve. The significance level was P = 0.05.ResultsSeveral DCE‐MRI parameters differentiated solid benign from malignant masses. Toft's rate constant (kep) was significantly higher in malignant masses (P &lt; 0.001), as well as quantitative T2 values (P = 0.003), and signal intensity on T2 weighted imaging (P = 0.008). A linear combination of the mean, standard deviation, skewness, and kurtosis of T2 within solid regions (area under the curve [AUC] 0.90) provided better classification accuracy than the mean of T2 alone (AUC 0.81).ConclusionQuantitative parameters from DCE‐MRI and T2 mapping can differentiate benign from malignant ovarian masses. J. Magn. Reson. Imaging 2013;38:1501–1509. © 2013 Wiley Periodicals, Inc.

Correlation of magnetic resonance diffusion tensor imaging and clinical findings of cervical myelopathy

Background contextDespite significant advances in the development of diagnostic technology, the diagnosis of cervical myelopathy (CM) still remains based on the clinical findings, which do not provide the means for a sufficiently accurate diagnosis. Furthermore, conventional magnetic resonance imaging (MRI) using T1- and T2-weighted sequences lacks sensitivity to detect and characterize spinal cord lesions. Considering these uncertainties, several investigators have assessed the diagnostic value of diffusion tensor imaging (DTI), an advanced MRI technique that measures the diffusion of water molecules. PurposeTo determine the diagnostic value of DTI in CM in reliably characterizing spinal lesions and in associating them with the clinical findings. Study design/settingProspective cohort study. Patient sampleFifteen CM patients and five healthy volunteers without a history of neurological disorders or of symptoms as controls. Outcome measuresSymptoms and signs of CM were evaluated by the use of a modified Japanese Orthopedic Score and the other clinical findings. T2-weighed MRI was used to note the number of compressed levels. Diffusion tensor imaging results were measured according to two parameters, fractional anisotropy (FA) and apparent diffusion coefficient (ADC), at anterior, lateral, and posterior regions of interest (ROIs) in each of five cervical vertebrae, C3–C7. MethodsOn diagnosis of CM by clinical evaluation and findings from T2-weighted MRI, the 15 subjects were assigned to two subgroups based on complaints, symptoms, and signs. The nine subjects who had typical CM symptoms such as motor weakness, gait disturbance, clumsiness of the hands, and unilateral hypesthesia were assigned to the paralysis subgroup. The other six subjects, whose main symptom was pain and who had vague signs of upper motor neuron injury despite a definitive finding of CM by T2-weighted MRI, were assigned to the pain subgroup. Once assignments had been made, subjects underwent DTI done by the use of the same scanner as for T2-weighted MRI. Results of DTI for each subgroup and controls were averaged, and the mean was used for comparisons. Diffusion tensor imaging results from the paralysis subgroup were sorted into affected and unaffected sides according to the presence or the absence of symptoms. ResultsThe paralysis subgroup and the pain subgroup had similar findings from T2-weighted MRI on presentation. The paralysis subgroup had statistically significantly decreased FA values in the anterior and lateral ROIs on the affected side and in the anterior ROIs on the unaffected side, compared with controls. The paralysis subgroup also had statistically significantly increased ADC values in the anterior ROIs of the affected side, compared with controls. The pain subgroup showed significantly increased ADC values in anterior, lateral, and posterior ROIs. ConclusionsUse of DTI to quantitatively compare compression in the cervical spinal cords of CM subjects and healthy controls explained individual differences in the clinical findings in the subjects. These findings even applied to CM subjects whose compressed spinal cords looked similar on conventional T2-weighted MRI. Therefore, DTI provided more accurate and reliable information than did conventional T2-weighted MRI about the relationship between spinal cord structure and clinical presentation of CM. Based on our DTI findings, we hypothesized that different clinical findings in CM are attributable to the stage of progression and the severity of pathologic change at presentation. We anticipate that the use of DTI to quantify the extent of myelopathological changes in CM could be more reliable than any other existing diagnostic tools and might provide invaluable information about selecting the optimal treatment for CM and predicting surgical outcomes and prognosis.

Effects of Subanesthetic Dose of Nitrous Oxide on Cerebral Blood Flow and Metabolism

Nitrous oxide, in a concentration of 50% or more, is a known cerebral vasodilator. This study investigated whether a lower dose (30%) of nitrous oxide would also increase cerebral blood flow. In addition, the authors wished to study whether the increase in cerebral blood flow was accompanied by an increase in cerebral metabolism. Multimodal Magnetic Resonance Imaging at 3T was performed, and data were obtained in 17 healthy volunteers during three inhalation conditions: medical air, oxygen-enriched medical air (40% oxygen), and 30% nitrous oxide with oxygen-enriched medical air (40% oxygen). Arterial spin labeling was used to derive the primary tissue specific hemodynamic outcomes: cerebral blood flow, arterial blood volume and arterial transit times. Magnetic Resonance Susceptometry and proton Magnetic Resonance Spectroscopy were used for secondary metabolic outcomes: venous oxygenation, oxygen extraction fraction, cerebral metabolic oxygen rate and prefrontal metabolites. Nitrous oxide in 40% oxygen, but not 40% oxygen alone, significantly increased gray matter cerebral blood flow (22%; P < 0.05) and arterial blood volume (41%; P < 0.05). Venous oxygenation increased in both oxygen and nitrous oxide conditions. Compared with medical air inhalation, nitrous oxide condition caused a significantly larger decrease in oxygen extraction fraction than 40% oxygen alone (mean [SD] 11.3 [5.6]% vs. 8.3 [5.9]% P < 0.05), while global cerebral metabolic rate and prefrontal metabolites remained unchanged. This study demonstrates that 30% nitrous oxide in oxygen-enriched air (40% oxygen) significantly increases cerebral perfusion, and reduces oxygen extraction fraction, reflecting a strong arterial vasodilatory effect without associated increases in metabolism.

Validation of novel calibration scheme with traceable point-like 22Na sources on six types of PET scanners

To improve the reliability and convenience of the calibration procedure of positron emission tomography (PET) scanners, we have been developing a novel calibration path based on traceable point-like sources. When using (22)Na sources, special care should be taken to avoid the effects of 1.275-MeV γ rays accompanying β (+) decays. The purpose of this study is to validate this new calibration scheme with traceable point-like (22)Na sources on various types of PET scanners. Traceable point-like (22)Na sources with a spherical absorber design that assures uniform angular distribution of the emitted annihilation photons were used. The tested PET scanners included a clinical whole-body PET scanner, four types of clinical PET/CT scanners from different manufacturers, and a small-animal PET scanner. The region of interest (ROI) diameter dependence of ROI values was represented with a fitting function, which was assumed to consist of a recovery part due to spatial resolution and a quadratic background part originating from the scattered γ rays. The observed ROI radius dependence was well represented with the assumed fitting function (R (2) > 0.994). The calibration factors determined using the point-like sources were consistent with those by the standard cross-calibration method within an uncertainty of ±4 %, which was reasonable considering the uncertainty in the standard cross-calibration method. This novel calibration scheme based on the use of traceable (22)Na point-like sources was successfully validated for six types of commercial PET scanners.

A Graph-Based Integration of Multimodal Brain Imaging Data for the Detection of Early Mild Cognitive Impairment (E-MCI).

Alzheimer's disease (AD) is the most common cause of dementia in older adults. By the time an individual has been diagnosed with AD, it may be too late for potential disease modifying therapy to strongly influence outcome. Therefore, it is critical to develop better diagnostic tools that can recognize AD at early symptomatic and especially pre-symptomatic stages. Mild cognitive impairment (MCI), introduced to describe a prodromal stage of AD, is presently classified into early and late stages (E-MCI, L-MCI) based on severity. Using a graph-based semi-supervised learning (SSL) method to integrate multimodal brain imaging data and select valid imaging-based predictors for optimizing prediction accuracy, we developed a model to differentiate E-MCI from healthy controls (HC) for early detection of AD. Multimodal brain imaging scans (MRI and PET) of 174 E-MCI and 98 HC participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort were used in this analysis. Mean targeted region-of-interest (ROI) values extracted from structural MRI (voxel-based morphometry (VBM) and FreeSurfer V5) and PET (FDG and Florbetapir) scans were used as features. Our results show that the graph-based SSL classifiers outperformed support vector machines for this task and the best performance was obtained with 66.8% cross-validated AUC (area under the ROC curve) when FDG and FreeSurfer datasets were integrated. Valid imaging-based phenotypes selected from our approach included ROI values extracted from temporal lobe, hippocampus, and amygdala. Employing a graph-based SSL approach with multimodal brain imaging data appears to have substantial potential for detecting E-MCI for early detection of prodromal AD warranting further investigation.

Evaluation of the Effect of Hemoglobin or Hematocrit Level on Dural Sinus Density Using Unenhanced Computed Tomography

PurposeTo identify the relationship between hemoglobin (Hgb) or hematocrit (Hct) level and dural sinus density using unenhanced computed tomography (UECT).Materials and MethodsPatients who were performed UECT and had records of a complete blood count within 24 hours from UECT were included (n=122). We measured the Hounsfield unit (HU) of the dural sinus at the right sigmoid sinus, left sigmoid sinus and 2 points of the superior sagittal sinus. Quantitative measurement of dural sinus density using the circle regions of interest (ROI) method was calculated as average ROI values at 3 or 4 points. Simple regression analysis was used to evaluate the correlation between mean HU and Hgb or mean HU and Hct.ResultsThe mean densities of the dural sinuses ranged from 24.67 to 53.67 HU (mean, 43.28 HU). There was a strong correlation between mean density and Hgb level (r=0.832) and between mean density and Hct level (r=0.840).ConclusionDural sinus density on UECT is closely related to Hgb and Hct levels. Therefore, the Hgb or Hct levels can be used to determine whether the dural sinus density is within the normal range or pathological conditions such as venous thrombosis.

Quantitative assessment of lung cancer tumor vascular parameters by using high speed perfusion CT: influence of tumor region of interest

Objective To prospectively determine whether position and size of tumor region of interest (ROI) influence estimates of lung cancer vascular parameters at 256-slice CT perfusion study.Methods After institutional review board approval and informed consent,16 men and 11 women with lung cancer underwent 70-second CT perfusion study. Perfusion, blood volume, peak enhancement weredetermined for 60 or 120 mm2 circular ROIs placed at the tumor edge and center and around (outlining) visible tumor. ROI analysis was repeated twice by two observers in the same way to get the average values.The correlation between the measurements and microvascular density counts was determined in 19 patients with operation.Measurements were compared by using Pair-Samples t test,a difference with P≤0.05 was significant.Results Perfusion,blood volume,peak enhancement measurements were substantially higher at the edge than at the center for both 60 and 120 mm2 ROI. For 60 and 120 mm2 ROI,median of the three measurements were (M=15.40,9.50 ml · min- 1 · 100 ml - 1,M =35.60,25.40 ml · 100 g-1,and M=16.47,10.20 HU),respectively,at the edge versus(M =14.80,8.52 ml · min- 1 · 100 ml- 1,M =33.50,23.90 ml · 100 g- 1,and M =15.64,9.40 HU),respectively,at the center(t value was 10.95,9.80,7.06,2.93,7.74 and 10.09,respectively,all P ＜ 0.05 ). Measurements varied substantially depending on the ROI size,values for the ROI for outlined tumor were intermediate between those at the tumor edge and center.Perfusion(M=12.51 ml.min- 1 · 100 ml-1),blood volume(M=29.31 ml.100 g-1),peakenhancement (M =12.93 HU) for the ROI outlining tumor were intermediate between those at the tumor edge and center.There was a good correlation between perfusion,blood volume,peak enhancement for the ROI outlining tumor and microvascular density[ ( 19.43 ± 8.78 ) vessels/0.74 mm2 ],respectively ( r value 0.732,0.590 and 0.544,all P ＜ 0.05 ).Conclusions Position and size of tumor ROI substantially influence ultimate perfusion values.ROI for outlined entire tumor is more reliable for perfusion measurements and more appropriate clinically than use of arbitrarily determined smaller ROI. Key words: Lung neoplasms; Tomography,X-ray computed; Perfusion

Prediction of cognitive decline based on hemispheric cortical surface maps of FDDNP PET

A cross-sectional study to establish whether a subject's cognitive state can be predicted based on regional values obtained from brain cortical maps of FDDNP Distribution Volume Ratio (DVR), which shows the pattern of beta amyloid and neurofibrillary binding, along with those of early summed FDDNP PET images (reflecting the pattern of perfusion) was performed. Dynamic FDDNP PET studies were performed in a group of 23 subjects (8 control (NL), 8 Mild Cognitive Impairment (MCI) and 7 Alzheimer's Disease (AD) subjects). FDDNP DVR images were mapped to the MR derived hemispheric cortical surface map warped into a common space. A set of Regions of Interest (ROI) values of FDDNP DVR and early summed FDDNP PET (0-6 min post tracer injection), were thus calculated for each subject which along with the MMSE score were used to construct a linear mathematical model relating ROI values to MMSE. After the MMSE prediction models were developed, the models' predictive ability was tested in a non-overlapping set of 8 additional individuals, whose cognitive status was unknown to the investigators who constructed the predictive models. Among all possible subsets of ROIs, we found that the standard deviation of the predicted MMSE was 1.8 by using only DVR values from medial and lateral temporal and prefrontal regions plus the early summed FDDNP value in the posterior cingulate gyrus. The root mean square prediction error for the eight new subjects was 1.6. FDDNP scans reflect progressive neuropathology accumulation and can potentially be used to predict the cognitive state of an individual.

Diffusion-Weighted Magnetic Resonance Imaging for Diagnosis of Liver Fibrosis and Inflammation in Chronic Viral Hepatitis: The Performance of Low or High b Values and Small or Large Regions of Interest

ObjectiveTo investigate the performance of different b values and regions of interest (ROI) for diagnosing liver fibrosis in patients with chronic viral hepatitis by using diffusion-weighted (DW) magnetic resonance imaging (MRI). MethodsEleven healthy participants and 33 patients with viral hepatitis B or C were enrolled. The stage of liver fibrosis and the grade of necroinflammation were determined by using a histologic activity index. Single-shot spin-echo echo-planar DW-MRI was performed in all participants at b values of 0-500, 0-700, and 0-1000 s/mm2 by using 2 circular small and large ROIs of 100 and 200 mm2. To evaluate the performance of different b values for determining cirrhosis, the receiver-operating characteristic curves were depicted, and the areas under the curves were compared. ResultsThe average values of apparent diffusion coefficients significantly decreased with increasing stage or grade categories at all the 3 b values and for both small and large ROIs. The performance at b = 500 s/mm2 was significantly better than b = 1000 s/mm2 for determining cirrhosis or bridging fibrosis. The cut point of 153.4 for apparent diffusion coefficient (×10−5 mm2/s) at b = 500 s/mm2 could determine cirrhosis or bridging fibrosis with a sensitivity of 96% and specificity of 82%. No difference was found between the average apparent diffusion coefficient values of large or small ROIs. Also, there was no difference in performance of large or small ROIs in the diagnosis of liver fibrosis. ConclusionsThis study provided beneficial data for clinical utilisation of DW-MRI in diagnosing liver fibrosis: b = 500 s/mm2 is better in performance than b = 1000 s/mm2, and a small ROI of 100 mm2 is sufficient for determining cirrhosis or bridging fibrosis.

Magnetic Resonance Imaging of Acute Scrotum

The aim of the pilot study was to evaluate the feasibility of dynamic contrast enhanced (CE)-magnetic resonance imaging (MRI) in the detection of testicular ischemia and its ability to differentiate testicle torsion from other causes of acute scrotum. Seventeen boys or young men with an acute scrotum were included in the prospective study during the time period from October 2001 to December 2005. The median age of the patients was 16,4 (7-44) years. The duration of the symptoms preceding the MRI study varied from six hours to 30 days. The study protocol included physical examination by a surgeon, laboratory tests and Doppler ultrasound (DUS) and finally testicles were imaged by using a 1,5 T MRI scanner; T1-weighted and diffusion weighted images were produced. The gadolinium uptake, reported as the region of interest (ROI) perfusion values and presented as curves, was compared between the affected and contralateral testicle. In testicles with normal blood circulation the ROI values increased during the imaging time. Nine patients were operated on, because the spermatic cord torsion could not be excluded by clinical or DUS findings. All the normal testicles gave increasing ROI values meanwhile all three testicles with torsion gave constantly low values referring to no perfusion. Other causes of acute scrotum, such as epididymitis and torsion of testicular appendage seemed to be related with normal perfusion. Dynamic CE-MRI seems to show reliably ischemia of testicle and thus it may be helpful in selecting patients with acute scrotum for urgent operation.