Average Apparent Diffusion Coefficient Research Articles

Combined PET imaging and diffusion-weighted imaging of intermediate and high-risk primary prostate carcinomas with simultaneous [18F] choline PET/MRI.

PurposeTo characterize intermediate and high-risk prostate carcinomas with measurements of standardized uptake values (SUVs) and apparent diffusion coefficient (ADC) values by means of simultaneous [18F] choline PET/MRI.Materials and Methods35 patients with primary prostate cancer underwent simultaneous [18F] choline PET/MRI. From these, 21 patients with an intermediate and high risk constellation who were not under ongoing hormonal therapy were included. Altogether 32 tumor lesions with a focal uptake of [18F] choline could be identified. Average ADC values (ADCaver) minimum ADC values (ADCmin) as well as maximum and mean SUVs (SUVmax, SUVmean) of tumor lesions were assessed with volume-of-interest (VOI) and Region-of-interest (ROI) measurements. As a reference, also ADCaver, ADCmin and SUVmax and SUVmean of non-tumorous prostate tissue were measured. Statistical analysis comprised calculation of descriptive parameters and calculation of Pearson’s product moment correlations between ADC values and SUVs of tumor lesions.ResultsMean ADCaver and ADCmin of tumor lesions were 0.94±0.22×10−3 mm2/s and 0.65±0.21×10−3 mm2/s, respectively. Mean SUVmax and SUVmean of tumor lesions were 6.3±2.3 and 2.6±0.8, respectively. These values were in each case significantly different from the reference values (p<0.001). There was no significant correlation between the measured SUVs and ADC values (SUVmax vs. ADCaver: R = −0.24, p = 0.179; SUVmax vs. ADCmin: R = −0.03, p = 0.877; SUVmean vs. ADCaver: R = −0.27, p = 0.136; SUVmean vs. ADCmin: R = −0.08, p = 0.679).ConclusionBoth SUVs and ADC values differ significantly between tumor lesions and healthy tissue. However, there is no significant correlation between these two parameters. This might be explained by the fact that SUVs and ADC values characterize different parts of tumor biology.

Is DWI/ADC a useful tool in the characterization of focal hepatic lesions suspected of malignancy?

ObjectiveApparent diffusion coefficient (ADC) values calculated through magnetic resonance imaging have been proposed as a useful tool to distinguish benign from malignant liver lesions. Most studies however included simple cysts in their analysis. Liver cysts are easy to diagnose, have very high ADC values and their inclusion facilitates differentiation in the ADC values between benign and malignant liver lesions groups. We prospectively evaluated the ability of ADC values to differentiate metastatic liver lesions from all benign or only solid benign liver lesions.Material and MethodsSixty-seven adult cancer patients with 188 liver lesions were evaluated. Lesions were categorized as metastatic or benign throughout imaging and clinical evaluation. One hundred and five (105) metastatic lesions and 83 benign lesions including hemangiomas (37), cysts (42), adenomas (2) and focal nodular hyperplasias (2) were evaluated. ADC values were calculated for each lesion utilizing two b values (0 and 600 sec/mm2).ResultsThe average ADC value for cysts was 2.4×10−3 mm2/sec (CI: 2.1–2.6), for solid benign lesions was 1.4×10−3 mm2/sec (CI: 1.1–1.7) and for metastases was 1.0×10−3 mm2/sec (CI: 0.8–1.3). There was a difference between the ADC values of metastases and benign solid lesions (p<0.0001). With the ADC value of 1.5×10−3 mm2/sec as a cut off it is possible to distinguish metastatic from benign liver lesions, including cysts, with an accuracy of 78%. But to distinguish metastatic from benign solid liver lesions the best ADC cut off value was 1.2×10−3 mm2/sec and the accuracy drops to 71%.ConclusionsADC values proved to be helpful in the distinction between metastasis and benign solid hepatic lesions. But the exclusion of cysts in the analysis point out to a lower cut off value and lower accuracy than previously reported.

High-resolution diffusion-weighted imaging of the prostate.

The purpose of this study was to evaluate the effect of increasing the spatial resolution of the prostate DWI protocol on image quality and lesion conspicuity. Twenty-nine patients with biopsy-proven prostate cancer undergoing MRI examinations were imaged with two diffusion-weighted imaging (DWI) protocols: current standard clinical protocol (6.7 mm(3) voxels) and a new high-resolution protocol (3.1 mm(3) voxels). Diffusion-weighted images were independently and subjectively scored on lesion conspicuity, internal architecture definition, and overall image quality by two radiologists. Average apparent diffusion coefficient (ADC) values were measured in normal tissue and cancerous lesions on both sequences. Reader scores and ADC and contrast values were compared between the two protocols. Cancer ADC values were correlated with Gleason scores. The signal-to-noise ratio of the new high-resolution DWI protocol was 40% lower than that of the standard protocol. The reader scores were higher by 0.73 (range, 0.29-1.16) grades, or 19% (range, 7-32%), on average, for the new protocol, indicating better image quality. The average ADC values were 8% higher with the new protocol, with ADC contrast values between cancer and normal prostate unchanged. There was marginally significant correlation of cancer ADC values with Gleason scores (p = 0.05, r ≈ -0.36). We showed that for DWI of the prostate at 3-7 mm(3) voxel sizes the benefits of higher spatial resolution outweigh the effects of reduced signal-to-noise and contrast-to-noise ratios, potentially improving the sensitivity to small or sparse prostate cancers. Radiologists can consider using higher-spatial-resolution DWI sequences in their practices.

The Role of Diffusion-Weighted Magnetic Resonance Imaging in the Treatment Response Evaluation of Hepatocellular Carcinoma Patients Treated With Radiation Therapy

We investigated the role of diffusion-weighted magnetic resonance imaging (DW MRI) as a response evaluation indicator for hepatocellular carcinoma (HCC) treated with radiation therapy (RT). Inclusion criteria of this retrospective study were DW MRI acquisition within 1 month before and 3 to 5 months after RT. In total, 48 patients were enrolled. Two radiation oncologists measured the apparent diffusion coefficient (ADC). Possible predictive factors, including alteration of the ADC value before and 3 to 5 month after RT, in relation to local progression-free survival (LPFS) were analyzed and compared. Three months after RT, 6 patients (12.5%) showed a complete response, and 27 patients (56.3%) showed a partial response when evaluated using the modified response evaluation criteria in solid tumors (mRECIST). The average ADC ± SD values were 1.21 ± 0.27 ( × 10(-3) mm(2)/s) before and 1.41 ± 0.36 ( × 10(-3) mm(2)/s) after RT (P<.001). The most significant prognostic factor related to LPFS was mRECIST (P<.001). The increment of ADC value (≥ 20%) was also a significant factor (P=.02), but RECIST (version 1.1; P=.11) was not. When RECIST was combined with the increment of ADC value (≥ 20%), the LPFS rates were significantly different between the groups (P=.004), and the area under the curve value (0.745) was comparable with that of mRECIST (0.765). ADC value change before and after RT in HCC was closely related to LPFS. ADC value and RECIST may substitute for mRECIST in patients who cannot receive contrast agents.

TU‐C‐12A‐06: Computerized Analysis of Diffusion‐Weighted Images in Breast Cancer Diagnosis

Purpose:Diffusion‐weighted imaging (DWI) for breast MRI is a non‐invasive technique which maps the diffusion process of water molecules, with the use of Brownian motion, in biological tissues, yielding apparent diffusion coefficients (ADC). Quantitative image analyses of the resulting images can yield information about the surrounding tissues in vivo. In this study, we investigated computerized image analyses of DWI images, including automated lesion segmentation, calculation of ADC values, and assessment of tumor heterogeneity, on a dataset of malignant and benign breast lesions.Method and Database:The IRB‐approved, retrospectively collected dataset included 46 breast lesions ‐‐ 36 malignant and 10 benign. The DW images had been acquired during clinical breast MRI on a high‐field 1.5 T echo‐planar system using five b values [b = 0, 500, 1000, 1500, and 2000 s/mm2]. Seed‐point‐initiated 3D Gaussian‐based lesion segmentation was conducted to yield the lesion margins, and within the margin and after b‐value fitting, ADC values were calculated. Average ADC values and various measures of heterogeneity were calculated for benign and malignant lesions.Results:Our findings showed that malignant lesions tended, as expected, to have lower ADC values relative to benign lesions with average ADC values for benign and malignant lesions being 1.70 +/− 0.50 × 10(−3) and 1.07 +/− 0.37 × 10(−3), respectively. In addition, malignant lesions showed higher heterogeneity. In the task of distinguishing between benign and malignant lesions, ROC analysis, from histogram analysis, yielded AUC values of 0.86 +/− 0.07 and 0.88 +/− 0.06 for average ADC values and standard deviation of ADC values, respectively.Conclusion:DWI exhibits potential for differentiating between benign and malignant lesions, and inclusion of computerized quantitative image analysis methods allow for more objectives and efficient calculations of the ADC values and their variations, for potential use in decision making.M. L. Giger is a stockholder in R2 Technology/Hologic, is a shareholder/investor in Quantitative Insights, Qview Medical,receives royalties from Hologic, GE Medical Systems, MEDIAN Technologies, Riverain Medical, Mitsubishi and Toshiba.

Effect of breast cancer phenotype on diagnostic performance of MRI in the prediction to response to neoadjuvant treatment

AimThe estimation of response to neoadjuvant chemotherapy (NAC) is useful in the surgical decision in breast cancer. We addressed the diagnostic reliability of conventional MRI, of diffusion weighted imaging (DWI) and of a merged criterion coupling morphological MRI and DWI. Diagnostic performance was analysed separately in different tumor subtypes, including HER2+ (human epidermal growth factor receptor 2)/HR+ (hormone receptor) (hybrid phenotype). Materials and methodsTwo-hundred and twenty-five patients underwent MRI before and after NAC. The response to treatment was defined according to the RECIST classification and the evaluation of DWI with apparent diffusion coefficient (ADC). The complete pathological response – pCR was assessed (Mandard classification). ResultsTumor phenotypes were Luminal (63.6%), Triple Negative (16.4%), HER2+ (7.6%) or Hybrid (12.4%). After NAC, pCR was observed in 17.3% of cases. Average ADC was statistically higher after NAC (p<0.001) among patients showing pCR vs. those who had not pCR. The RECIST classification showed adequate performance in predicting the pCR in Triple Negative (area under the receiver operating characteristic curve, ROC AUC=0.9) and in the HER2+ subgroup (AUC=0.826). Lower performance was found in the Luminal and Hybrid subgroups (AUC 0.693 and 0.611, respectively), where the ADC criterion yielded an improved performance (AUC=0.787 and 0.722). The coupling of morphological and DWI criteria yielded maximally improved performance in the Luminal and Hybrid subgroups (AUC=0.797 and 0.761). ConclusionThe diagnostic reliability of MRI in predicting the pCR to NAC depends on the tumor phenotype, particularly in the Luminal and Hybrid subgroups. In these cases, the coupling of morphological MRI evaluation and DWI assessment may facilitate the diagnosis.

Intercentre reproducibility of cardiac apparent diffusion coefficient and fractional anisotropy in healthy volunteers.

BackgroundDiffusion tensor cardiac magnetic resonance (DT-CMR) enables probing of the microarchitecture of the myocardium, but the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) reported in healthy volunteers have been inconsistent. The aim of this study was to validate a stimulated-echo diffusion sequence using phantoms, and to assess the intercentre reproducibility of in-vivo diffusion measures using the sequence.Methods and resultsA stimulated-echo, cardiac-gated DT-CMR sequence with a reduced-field-of-view, single-shot EPI readout was used at two centres with 3 T MRI scanners. Four alkane phantoms with known diffusivities were scanned at a single centre using a stimulated echo sequence and a spin-echo Stejskal-Tanner diffusion sequence. The median (maximum, minimum) difference between the DT-CMR sequence and Stejskal-Tanner sequence was 0.01 (0.04, 0.0006) × 10-3 mm2/s (2%), and between the DT-CMR sequence and literature diffusivities was 0.02 (0.05, 0.006) × 10-3 mm2/s (4%).The same ten healthy volunteers were scanned using the DT-CMR sequence at the two centres less than seven days apart. Average ADC and FA were calculated in a single mid-ventricular, short axis slice. Intercentre differences were tested for statistical significance at the p < 0.05 level using paired t-tests. The mean ADC ± standard deviation for all subjects averaged over both centres was 1.10 ± 0.06 × 10-3 mm2/s in systole and 1.20 ± 0.09 × 10-3 mm2/s in diastole; FA was 0.41 ± 0.04 in systole and 0.54 ± 0.03 in diastole. With similarly-drawn regions-of-interest, systolic ADC (difference 0.05 × 10-3 mm2/s), systolic FA (difference 0.003) and diastolic FA (difference 0.01) were not statistically significantly different between centres (p > 0.05), and only the diastolic ADC showed a statistically significant, but numerically small, difference of 0.07 × 10-3 mm2/s (p = 0.047). The intercentre, intrasubject coefficients of variance were: systolic ADC 7%, FA 6%; diastolic ADC 7%, FA 3%.ConclusionsThis is the first study to demonstrate the accuracy of a stimulated-echo DT-CMR sequence in phantoms, and demonstrates the feasibility of obtaining reproducible ADC and FA in healthy volunteers at separate centres with well-matched sequences and processing.

Validation of Quantitative Analysis of Multiparametric Prostate MR Images for Prostate Cancer Detection and Aggressiveness Assessment: A Cross-Imager Study

To validate three previously identified quantitative image features across multiparametric magnetic resonance (MR) images acquired with imagers made by two different manufacturers to differentiate prostate cancer (PC) from normal prostatic tissue and to assess cancer aggressiveness. This study was HIPAA-compliant and approved by the institutional review board. Preoperative 1.5-T multiparametric endorectal MR images of 119 PC patients (dataset A, 71 patients; dataset B, 48 patients) were analyzed, and 265 PC and normal peripheral zone regions of interests (ROIs) were identified through histologic and MR consensus review. The 10th percentile average apparent diffusion coefficient (ADC) value, average ADC value, and skewness of T2-weighted signal-intensity histogram were evaluated with area under the receiver operating characteristic curve (AUC). The image features were combined with a linear discriminant analysis classifier and evaluated both on the image dataset of each type of imager alone (leave-one-patient-out evaluation) and across the datasets (training on one dataset, testing on the other). Spearman correlation coefficient was calculated between the image features and ROI-specific Gleason scores. AUC values of the image features combined were 0.95 ± 0.02 (standard error) and 0.88 ± 0.03 on dataset B and dataset A alone, respectively, and 0.96 ± 0.02 and 0.89 ± 0.03 when training on dataset A and testing on dataset B and vice versa, respectively. Spearman correlation coefficients between Gleason scores and the ADC features were between -0.27 and -0.34. Consistently across images from datasets A and B, the 10th percentile ADC value, average ADC value, and T2-weighted skewness can distinguish PC from normal-tissue ROIs, and ADC features correlate moderately with ROI-specific Gleason scores.

Magnetic resonance imaging with diffusion-weighted imaging in the evaluation of thyroid-associated orbitopathy: getting below the tip of the iceberg

To compare extraocular muscles (EOMs) T2, post-contrast T1 (T1Gad) signal intensity ratios (SIRs) and normalized-apparent diffusion coefficient (n-ADC) values in patients with thyroid-associated orbitopathy (TAO) at different phases of activity and severity and correlate MRI modifications to clinical evolution during follow-up. A total of 74 TAO patients were classified as active or inactive on the basis of the clinical activity score (CAS). Severity of EOM impairment was evaluated by assigning a functional score to each rectus. T2, T1Gad SIRs and n-ADC of EOMs were compared in patients with active inflammation, those with inactive disease and 26 healthy controls, and correlated with clinical scores. MRI parameter variation was correlated with clinical modifications during follow-up. All MRI parameters in TAO EOMs were significantly higher than in healthy subjects and correlated with muscle dysfunction and CAS. EOMs of active patients showed higher T2 and T1Gad SIRs than those with inactive disease. The T2 SIR and n-ADC of normally functioning TAO EOMs were higher than those of healthy controls. SIRs decreased in clinically improved and clinically stable EOMs after therapy. T2 SIR, T1Gad SIR and n-ADC are objective measures of activity and severity of EOMs in TAO patients. MRI shows clinically silent muscle involvement and modifications. • MRI and DWI measures are objective, quantitative parameters of TAO activity and severity • MRI and DWI measures significantly correlate with clinical scores in TAO patients • MRI and DWI can identify clinically silent inflammation of deep orbital structures • MRI and DWI can depict subclinical modifications during follow-up • MRI and DWI may aid clinicians in choosing the most appropriate treatment.

Comparison of ADC values of intracranial hemangiopericytomas and angiomatous and anaplastic meningiomas

This study aimed to determine whether the use of apparent diffusion coefficient (ADC) values can improve the diagnostic efficacy of magnetic resonance imaging (MRI) to differentiate hemangiopericytoma (HPC) from angiomatous and anaplastic meningioma. Preoperative diffusion-weighted imaging (DWI) studies of 38 patients with pathologically proven intracranial HPC (n = 12) and angiomatous (n = 13) or anaplastic meningioma (n = 13) were retrospectively reviewed. ADC values were measured in the tumor parenchyma and peritumoral edema, and used to obtain normalized ADC (NADC) ratios (ADC of tumor/ADC of normal white matter). Mean ADC values were significantly different between HPC and anaplastic meningioma (1.17 ± 0.30 × 10(-3) mm(2)/s and 0.75 ± 0.11 × 10(-3) mm(2)/s, respectively). Mean NADC ratios were also significantly lower in the malignant cases (0.95 ± 0.13) compared with the benign HPCs (1.53 ± 0.39; P < 0.05). Mean ADC values and NADC ratios did not differ significantly between angiomatous meningioma and HPC (P > 0.05), whereas mean ADC values and NADC ratios were lower for anaplastic meningioma than for either angiomatous meningioma or HPC (P < 0.05). Mean ADC value in peritumoral edema in HPC (1.48 ± 0.11 × 10(-3) mm(2)/s) was lower than in either angiomatous (1.73 ± 0.28 × 10(-3) mm(2)/s) or anaplastic (1.72 ± 0.25 × 10(-3) mm(2)/s) meningioma (P < 0.05), and there was no significant difference between ADC values in anaplastic versus angiomatous meningioma (P > 0.05). ADC values in tumor parenchyma and peritumoral edema can provide helpful information that is otherwise not available from conventional MRI to differentiate HPC from angiomatous and anaplastic meningioma.

Analysis of diffusion tensor imaging metrics for gliomas grading at 3 T

ObjectivesTo assess the diagnostic accuracy of axial diffusivity (AD), radial diffusivity (RD), apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values derived from DTI for grading of glial tumors, and to estimate the correlation between DTI parameters and tumor grades. MethodsSeventy-eight patients with glial tumors underwent DTI. AD, RD, ADC and FA values of tumor, peritumoral edema and contralateral normal-appearing white matter (NAWM) and AD, RD, ADC and FA ratios: lowest average AD, RD, ADC and FA values in tumor or peritumoral edema to AD, RD, ADC and FA of NAWM were calculated.DTI parameters and tumor grades were analyzed statistically and with Pearson correlation. Receiver operating characteristic (ROC) curve analysis was also performed. ResultsThe differences in ADC, AD and RD tumor values, and ADC and RD tumor ratios were statistically significant between grades II and III, grades II and IV, and between grades II and III–IV. The AD tumor ratio differed significantly among all tumor grades.Tumor ADC, AD, RD and glial tumor grades were strongly correlated. In the ROC curve analysis, the area under the curve (AUC) of the parameter tumor ADC was the largest for distinguishing grade II from grades III to IV (98.5%), grade II from grade IV (98.9%) and grade II from grade III (97.0%). ConclusionADC, RD and AD are useful DTI parameters for differentiation between low- and high-grade gliomas with a diagnostic accuracy of more than 90%. Our study revealed a good inverse correlation between ADC, RD, AD and WHO grades II–IV astrocytic tumors.

The Role of 3 Tesla Diffusion-Weighted Imaging in the Differential Diagnosis of Benign versus Malignant Cervical Lymph Nodes in Patients with Head and Neck Squamous Cell Carcinoma

Objective. The aim of this study was to validate the role of diffusion-weighted imaging (DWI) at 3 Tesla in the differential diagnosis between benign and malignant laterocervical lymph nodes in patients with head and neck squamous cell carcinoma (HNSCC). Materials and Methods. Before undergoing surgery, 80 patients, with biopsy proven HNSCC, underwent a magnetic resonance exam. Sensitivity (Se) and specificity (Spe) of conventional criteria and DWI in detecting laterocervical lymph node metastases were calculated. Histological results from neck dissection were used as standard of reference. Results. In the 239 histologically proven metastatic lymphadenopathies, the mean apparent diffusion coefficient (ADC) value was 0.903 × 10−3 mm2/sec. In the 412 pathologically confirmed benign lymph nodes, an average ADC value of 1.650 × 10−3 mm2/sec was found. For differentiating between benign versus metastatic lymph nodes, DWI showed Se of 97% and Spe of 93%, whereas morphological criteria displayed Se of 61% and Spe of 98%. DWI showed an area under the ROC curve (AUC) of 0.964, while morphological criteria displayed an AUC of 0.715. Conclusions. In a DWI negative neck for malignant lymph nodes, the planned dissection could be converted to a wait-and-scan policy, whereas DWI positive neck would support the decision to perform a neck dissection.

The correlation of apparent diffusion coefficient values with gender and age in normal adult pancreas

Objective To investigate the effect of gender and age on the apparent diffusion coefficient (ADC) of normal adult pancreas. Methods A total of 383 patients with normal pancreas (290 male,93 female,range from 21 to 78 years of age) were enrolled in this study.The subjects were divided into four groups based on different age (≤40 years,41-50 years,51-60 years and>60 years) with patient number of 56,108,139 and 80,respectively.Breath-hold single-shot echo-planar DWI (b value=0,500 s/mm2) was performed to determine ADCs on all patients.The average ADCs was calculated by four ADCs measured from the head to tail part of the pancreas in each patient.Patients with different age or gender were analyzed by independent-samples t test.Effect of gender on ADCs was analyzed using the Mann-Whitney U test.Relationship between ADCs and age was analyzed using Spearman rank-order correlation test,and Kruskal-Wallis H test was used to compare the ADCs among 4 age groups. Results The median pancreatic ADC values in female group (n=93) [1.60×10-3mm2/s (1.47×10-3-1.77×10-3) mm2/s] was higher than that in male group (n=290) [1.57×10-3mm2/s (1.41×10-3-1.74×10-3) mm2/s].Mann-Whitney U test results showed the mean ADCs was similar between the two groups (Z=1.335,P=0.182).The age distribution was similar between the male[ (52±10) years of age]and female[ (51±11) years of age] groups (t=0.267,P=0.790).The age spectrum showed that there was no correlation between the average ADC values and age (r=0.016,P=0.752).The median ADC values of the four age groups were 1.58×10-3,1.54×10-3,1.59×10-3and 1.57×10-3mm2/s,respectively.Kruskal-Wallis H test showed no significant difference of mean ADCs among the age groups (χ2=2.15,P=0.542). Conclusion There is no correlation of ADCs between age and gender in normal adult pancreas. Key words: Pancreas; Diffusion magnetic resonance imaging; Age factors; Sex factors

Diagnostic value of apparent diffusion coefficient for the accurate assessment and differentiation of intracranial meningiomas

BackgroundDiffusion-weighted imaging (DWI) along with the calculation of apparent diffusion coefficient (ADC), is a novel, non-invasive, and reliable technique of choice for accurate assessment and for the treatment planning of different types of brain tumors. It is more advantageous in the distinction and differentiation of benign from malignant meningiomas on the basis of ADC values.PurposeTo investigate the utility of DW magnetic resonance imaging (MRI), and to compare the apparent diffusion coefficient (ADC) obtained at two b-values for an authentic and preoperative characterization of meningiomas.Material and MethodsTwenty-six patients with clinically diagnosed or histologically verified meningioma (18 benign and 8 malignant) underwent imaging including DWI at 1.5 T. DW images were obtained at b = 1000 s/mm2 and b = 2000 s/mm2, ADC maps were generated at both the b-values. Signal intensities (SIs) and ADCs for solid tumorous tissues, contralateral normal tissues, and peritumoral edema were calculated and normalized ADC (NADC) ratio were determined for tumorous tissues. SI scores, ADC maps, and ADC values were analyzed visually and quantitatively, and were compared at both the b-values.ResultsDW images at b = 2000 s/mm2 were more conspicuity (either hyperintense or hypointense) with improved contrast. The mean ADC of malignant meningiomas (0.64 ± 0.05 and 0.42 ± 0.03) was significantly lower (P < 0.05) as compared with benign meningiomas (1.04 ± 0.12 and 0.80 ± 0.07) at both the b-values. Mean NADC ratio in the malignant type was also significantly lower (P < 0.05) than the benign type at both the b-values. Mean ADC values for peritumoral edema do not differ between benign and malignant meningiomas.Conclusion1.5-T DWI using high b-values improved our ability to differentiate benign from malignant meningiomas. DWI may play an important role in the preoperative radiological evaluation and the recognition of these types for proper surgical treatment.

Pilot study of a novel tool for input-free automated identification of transition zone prostate tumors using T2- and diffusion-weighted signal and textural features

To present results of a pilot study to develop software that identifies regions suspicious for prostate transition zone (TZ) tumor, free of user input. Eight patients with TZ tumors were used to develop the model by training a Naïve Bayes classifier to detect tumors based on selection of most accurate predictors among various signal and textural features on T2-weighted imaging (T2WI) and apparent diffusion coefficient (ADC) maps. Features tested as inputs were: average signal, signal standard deviation, energy, contrast, correlation, homogeneity and entropy (all defined on T2WI); and average ADC. A forward selection scheme was used on the remaining 20% of training set supervoxels to identify important inputs. The trained model was tested on a different set of ten patients, half with TZ tumors. In training cases, the software tiled the TZ with 4 × 4-voxel "supervoxels," 80% of which were used to train the classifier. Each of 100 iterations selected T2WI energy and average ADC, which therefore were deemed the optimal model input. The two-feature model was applied blindly to the separate set of test patients, again without operator input of suspicious foci. The software correctly predicted presence or absence of TZ tumor in all test patients. Furthermore, locations of predicted tumors corresponded spatially with locations of biopsies that had confirmed their presence. Preliminary findings suggest that this tool has potential to accurately predict TZ tumor presence and location, without operator input.

Voxel-based analysis of diffusion tensor indices in the brain of the patients with type II diabetes mellitus

Objective To evaluate early occult brain damage by diffusion tensor imaging in patients with typeⅡdiabetes mellitus. Methods High resolution three-dimensional T1-weighted fast spoiled gradient recalled echo MRI images and diffusion tensor imaging were obtained from 16 patients with typeⅡdiabetes mellitus (T2DM) and 16 normal controls (NC).Average apparent diffusion coefficient (ADC) map and fractional anisotropy (FA) map were calculated and analyzed with voxelbased analysis.Analysis of covariance was performed to compare ADC and FA between T2DM and NC. Results Increased ADC values of gray matter were demonstrated in right superior temporal gyrus,middle frontal gyrus,anterior cingulate gyrus,middle cingulate gyrus,inferior occipital gyrus,and left lingual gyrus,operculum orbitale,fusiform gyrus and parahippocampal gyrus in T2DM (voxel numbers in clusters were 176—3125,P<0.01).And increased ADC values of white matter were demonstrated in the regions of right middle temporal lobe,linual lobe,middle frontal lobe,calcarine gyrus,superior parietal lobe,and left operculum orbitale in T2DM patients compared with NC (voxel numbers in clusters were 200—781,P<0.01).Decreased FA values of gray matter were mainly located in left thalamus,bilateral caudate nuclei and right cuneus in T2DM (voxel numbers in clusters were 210—1402,P<0.01).Decreased FA values of white matter were demonstrated in the regions of right cuneus and the body of corpus callosum in T2DM (voxel numbers in clusters were 206,253,P<0.01). Conclusions The occult brain damage is demonstrated as increased ADC values and decreased FA values in regional brain parenchyma in typeⅡdiabetes mellitus.Voxel-based analysis of diffusion tensor indices may be a simple and effective tool for the evaluation of occult brain damage in typeⅡdiabetes mellitus. Key words: Diabetes mellitus,typeⅡ; Brain; Diffusion magnetic resonance imaging

Hybrid multidimensional T2 and diffusion‐weighted MRI for prostate cancer detection

To study the dependence of apparent diffusion coefficient (ADC) and T2 on echo time (TE) and b-value, respectively, in normal prostate and prostate cancer, using two-dimensional MRI sampling, referred to as "hybrid multidimensional imaging." The study included 10 patients with biopsy-proven prostate cancer who underwent 3 Tesla prostate MRI. Diffusion-weighted MRI (DWI) data were acquired at b = 0, 750, and 1500 s/mm(2) . For each b-value, data were acquired at TEs of 47, 75, and 100 ms. ADC and T2 were measured as a function of b-value and TE, respectively, in 15 cancer and 10 normal regions of interest (ROIs). The Friedman test was used to test the significance of changes in ADC as a function of TE and of T2 as a function of b-value. In normal prostate ROIs, the ADC at TE of 47 ms is significantly smaller than ADC at TE of 100 ms (P = 0.0003) and T2 at b-value of 0 s/mm(2) is significantly longer than T2 at b-value of 1500 s/mm(2) (P = 0.001). In cancer ROIs, average ADC and T2 values do not change as a function of TE and b-value, respectively. However, in many cancer pixels, there are large decreases in the ADC as a function of TE and large increases in T2 as a function of b-value. Cancers are more conspicuous in ADC maps at longer TEs. Parameters derived from hybrid imaging that depend on coupled/associated values of ADC and T2 may improve the accuracy of MRI in diagnosing prostate cancer.

SU-F-500-02: Early Prediction of Brain Metastases Response to Radiation Therapy by Combination of Changes in Tumor Vascular and Cellularity Properties

Purpose: To investigate the impact of combining image-based measurements related to alterations of vascular and cellularity properties of brain metastases for early prediction of tumor response to radiation therapy (RT). Methods: 24 patients undergoing treatment for metastases had perfusion (DCE) and diffusion MRI scans. Tumor subvolumes with high regional cerebral blood volume (rCBV) and high Gd-DTAP transfer constant (Ktrans) were extracted. The apparent diffusion coefficient (ADC) histograms of the tumor volume were categorized into low, normal and high ADC subvolumes. Changes in different tumor subvolumes and their combination from pre-RT to week 2 after start of radiation were evaluated in differentiation of responsive, stable and progressive tumors for patients treated by either whole brain radiation therapy (WBRT, 28 lesions) alone or combined with Bortezomib as a radiation sensitizer (39 lesions). Receiver Operating Characteristic (ROC) analysis compared a combined perfusion/diffusion prediction model with changes in gross tumor volume (GTV) within the same time interval. Results: For lesions treated with WBRT alone, a decrease in both high cellularity and edema subvolumes were associated with response. A decrease in the tumor subvolumes with high cellularity and vascularity was associated with response in lesions treated with RT combined with Bortezomib. In ROC analysis, areas under curve (AUCs) of 0.96 (WBRT alone) and 0.96 (WBRT + Bortezomib) were seen in prediction of non-responsive lesions when changes in different subvolumes were combined. Also, GTV changes could predict the non-responsive lesions treated with WBRT alone (AUC = 0.91) but failed to predict the response in lesions treated with WBRT combined with Bortezomib (AUC = 0.57). Conclusion: Combining the changes in tumor cellularity and vascularity could be used for early prediction of brain metastases response to RT and perform better than the GTV changes, suggesting that physiological changes could occur earlier than the morphological changes. (Support: NIH RO1NS064973) NIH grant ROl NS064973

1469 ADC VALUES FROM DIFFUSION-WEIGHTED MRI AS A PREDICTOR OF THE GLEASON SCORE IN PROSTATE CANCER

You have accessJournal of UrologyProstate Cancer: Detection & Screening (II)1 Apr 20131469 ADC VALUES FROM DIFFUSION-WEIGHTED MRI AS A PREDICTOR OF THE GLEASON SCORE IN PROSTATE CANCER Yoichi Kakuta, Satoshi Takahashi, Yosuke Sekii, Kinzo Katayama, Takuji Hayashi, Akihito Kamoto, Naoki Mori, Ryou Sugihara, Koji Yamamoto, Hiroaki Itatani, and Toshiaki Yoshioka Yoichi KakutaYoichi Kakuta Osaka, Japan More articles by this author , Satoshi TakahashiSatoshi Takahashi Kobe, Japan More articles by this author , Yosuke SekiiYosuke Sekii Osaka, Japan More articles by this author , Kinzo KatayamaKinzo Katayama Osaka, Japan More articles by this author , Takuji HayashiTakuji Hayashi Osaka, Japan More articles by this author , Akihito KamotoAkihito Kamoto Osaka, Japan More articles by this author , Naoki MoriNaoki Mori Osaka, Japan More articles by this author , Ryou SugiharaRyou Sugihara Osaka, Japan More articles by this author , Koji YamamotoKoji Yamamoto Osaka, Japan More articles by this author , Hiroaki ItataniHiroaki Itatani Osaka, Japan More articles by this author , and Toshiaki YoshiokaToshiaki Yoshioka Osaka, Japan More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2934AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES PSA screening has increased the detection of prostate cancer. However, a risk exists concerning the overdiagnosis and over-treatment of insignificant localized prostate cancers. The objective of our study was to determine the relationship between the apparent diffusion coefficient (ADC) value on DWI and the Gleason score of biospy-proven prostate cancer, and to investigate the relevance of the ADC value and clinical prognosis after the treatment. METHODS We retrospectively analyzed 1208 lobes of prostates from 604 patients who were suspected of having prostate cancer and who underwent an MRI at 1.5T before prostate biopsy between July 2009 and March 2012 at the Sumitomo Hospital. Regions of interest (ROIs) were drawn on ADC maps at sites of visible tumors on T2, DW images and ADC maps. If there were no visible tumors, five 30 mm2 lesions were drawn randomly and the average ADC value was calculated. RESULTS 546 lesions (45.2 %) were confirmed as prostate cancer by transrectal needle biopsies. ADC values for the lesions diagnosed as prostate cancer were significantly lower than those with no prostate cancer ( 899.1 ± 297.1 mm2/s v.s. 1424.7 ± 211.8 mm2/s, p<0.001). When the cut off for the ADC value was set at 1000 mm2/s, the positive predictive value for the ADC map was 95.0 %, and the negative predictive value was 90.0 %. The average ADC value of prostate cancer with a Gleason score of 6 was 1207.7 ± 277.5 mm2/s; Gleason score of 7, 1052.2 ± 224.3 mm2/s; Gleason score of 8, 798.0 ± 164.4 mm2/s; Gleason score of 9, 663.3 ± 184.6 mm2/s; Gleason score of 10, 455.6 ± 96.6 mm2/s. In some lesions with a Gleason score of 6 and 7 which had ADC values lower than 1000 mm2/s, it was ascertained that lesions with Gleason scores of 8 or 9 were included in the same lesion after prostatectomy. Patients, who were with diagosed prostate cancer with Gleason scores of 6 and 7 by needle biopsy and with low ADC values, had earlier PSA failure after the treatment than those with high ADC values. CONCLUSIONS Prostate cancer with high Gleason scores had lower ADC values than that with low Gleason scores. Patients diagnosed the prostate cancer with low ADC values appeared to have a poor clinical prognosis. ADC map may become useful tool for detecting clinically significant cases of prostate cancer. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e602 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Yoichi Kakuta Osaka, Japan More articles by this author Satoshi Takahashi Kobe, Japan More articles by this author Yosuke Sekii Osaka, Japan More articles by this author Kinzo Katayama Osaka, Japan More articles by this author Takuji Hayashi Osaka, Japan More articles by this author Akihito Kamoto Osaka, Japan More articles by this author Naoki Mori Osaka, Japan More articles by this author Ryou Sugihara Osaka, Japan More articles by this author Koji Yamamoto Osaka, Japan More articles by this author Hiroaki Itatani Osaka, Japan More articles by this author Toshiaki Yoshioka Osaka, Japan More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Diagnostics to Look beyond the Normal Appearing Brain Tissue (NABT)? A Neuroimaging Study of Patients with Primary Headache and NABT Using Magnetization Transfer Imaging and Diffusion Magnetic Resonance

Novel diagnostics can allow us to "look beyond" normal-appearing brain tissue (NABT) to unravel subtle alterations pertinent to the pathophysiology of primary headache, one of the most common complaints of patients who present to their physician across the medical specialties. Using both magnetization transfer imaging (MTI) and diffusion weighted imaging (DWI), we assessed the putative microstructural changes in patients with primary headache who display the NABT on conventional magnetic resonance imaging (conventional MRI). Subjects were 53 consecutive patients with primary headache disorders (40 = migraine with aura; 9 = tension headache; 4 = cluster headache) and 20 sex- and age-matched healthy volunteers. All subjects underwent evaluation with MRI, MTI, and DWI in order to measure the magnetization transfer ratio (MTR) and the apparent diffusion coefficient (ADC), respectively, in eight and six different regions of interest (ROIs). Compared to healthy controls, we found a significant 4.3 % increase in the average ADC value of the occipital white matter in the full sample of patients (p = 0.035) and in patients with migraine (p = 0.046). MTR values did not differ significantly in ROIs between patients and healthy controls (p > 0.05). The present study lends evidence, for the first time to the best of our knowledge, for a statistically significant microstructural change in the occipital lobes, as measured by ADC, in patients with primary headache who exhibit a NABT on MRI. Importantly, future longitudinal mechanistic clinical studies of primary headache (e.g., vis-à-vis neuroimaging biomarkers) would be well served by characterizing, via DWI, occipital white matter microstructural changes to decipher their broader biological significance.