Magnetic Resonance Apparent Diffusion Coefficient Research Articles

Determination of hemorrhagic transformation risk in acute ischemic cerebrovascular disease: The relationship between ADC values and GRE hemo sequence microhemorrhage.

<p>To determine the risk of hemorrhagic transformation in patients with acute ischemic cerebrovascular disease, we investigated the relationship between Apparent Diffusion Coefficient Magnetic Resonance Imaging values measured within the infarct area and microbleeds observed on Gradient Echo Sequence Magnetic Resonance Imaging.</p>. <p>A total of 172 patients who were hospitalized to the Neurology Clinic of the Istanbul Provincial Directorate of Health Erenkoy Mental and Nervous Diseases Training and Research Hospital between June 2019 and March 2020 were included in this cross-sectional study. The patients were classified according to their demographic and clinical characteristics, by age, gender, hypertension, diabetes mellitus, smoking, and alcohol use. In the Cranial Magnetic Resonance Imaging taken in the application for the diagnosis of acute ischemic cerebrovascular disease, the infarction area in Apparent Diffusion Coefficient sequences with the Region of Interest value and the relationship between microhemorrhage observed in Gradient Echo hemo-sequence was evaluated in Magnetic Resonance Imaging applied between 3-7 days. While calculating spherical Region of Interest values, 5 Region of Interest values were obtained for lesions larger than 1.5x1.5 cm, and their arithmetic mean was obtained, and single spherical Region of Interest value was taken for smaller ones. Apparent Diffusion Coefficient Magnetic Resonance Imaging Region of Interest mean values were divided into 2 groups as &lt;500x10&ndash;6 mm2 /s and &gt;500x10&ndash;6 mm2/s.&nbsp;</p>. <p>Patients in the group with Apparent Diffusion Coefficient Region of Interest mean values below 500x10-6 mm2/s, had a significantly higher probability for microhemorrhage observes in Gradient Echo Sequence Magnetic Resonance Imaging (p: 0.001) and also more likely to experience microhemorrhage in other areas, which was statistically significant (p: 0.001).The probability of another micro-bleeding observed in patients with microhemorrhage Gradient Echo Sequence Magnetic Resonance Imaging was also statistically significant (p: 0,001). The risk of microbleeding in areas other than ischemia was also found to be significantly higher in patients with microbleeding in the ischemia area in Gradient Echo Sequence Magnetic Resonance Imaging.</p>. <p>In our study, a statistically significant relationship was found between the microhemorrhage in the infarct area and the Apparent Diffusion Coefficient Region of Interest values. When the literature was reviewed, no such study was found to determine the risk of bleeding.</p>.

Plan Assessment Metrics for Dose Painting in Stereotactic Radiosurgery

As radiation therapy treatment precision increases with advancements in imaging and radiation delivery, dose painting treatment becomes increasingly feasible, where targets receive a nonuniform radiation dose. The high precision of stereotactic radiosurgery (SRS) makes it a good candidate for dose painting treatments, but no suitable metrics to assess dose painting SRS plans exist. Existing dose painting assessment metrics weigh target overdose and underdose equally but are unsuited for SRS plans, which typically avoid target underdose more. Current SRS metrics also prioritize reducing healthy tissue dose through selectivity and dose fall-off, and these metrics assume single prescriptions. We propose a set of metrics for dose painting SRS that would meet clinical needs and are calculated with nonuniform dose painting prescriptions. Sample dose painting SRS prescriptions are first created from Gamma Knife SRS cases, apparent diffusion coefficient magnetic resonance images, and various image-to-prescription functions. Treatment plans are found through semi-infinite linear programming optimization and using clinically determined isocenters, then assessed with existing and proposed metrics. Modified versions of SRS metrics are proposed, including coverage, selectivity, conformity, efficiency, and gradient indices. Quality factor, a current dose painting metric, is applied both without changes and with modifications. A new metric, integral dose ratio, is proposed as a measure of target overdose. The merits of existing and modified metrics are demonstrated and discussed. A modified conformity index using mean or minimum prescription dose would be suitable for dose painting SRS with integral or maximum boost methods, respectively. Either modified efficiency index is a suitable replacement for the existing gradient index. The proposed modified SRS metrics are appropriate measures of plan quality for dose painting SRS plans and have the advantage of giving equal values as the original SRS metrics when applied to single-prescription plans.

Evaluation of Diffusion-Perfusion Mismatch in Acute Ischemic Stroke with a New Automated Perfusion-Weighted Imaging Software: A Retrospective Study.

The aim of this study was to evaluate the accuracy of automated software (iStroke) on magnetic resonance (MR) apparent diffusion coefficient (ADC) and perfusion-weighted imaging (PWI) against ground truth in assessing infarct core, and compare the hypoperfusion volume and mismatch volume on iStroke with those on Food and Drug Administration-approved software (RAPID) in patients with acute ischemic stroke. We used the single-volume decomposition method to develop the iStroke (iStroke; Beijing Tiantan Hospital, Beijing, China) software. Patients with ischemic stroke were collected from two educational hospitals in China with MR-PWI performed in the emergency department within 24h of symptom onset. Infarct core volume was defined as ADC < 620 × 10-6 mm2/s and hypoperfusion volume was defined as Tmax > 6s. We compared the accuracy of infarct core volume using iStroke and RAPID (iSchema View Inc, Menlo Park, CA) software with ground truth. We included 405 patients with acute ischemic stroke with MR ADC and PWI sequences. The infarct core volume on iStroke (median 2.43ml, interquartile range [IQR] 0.60-10.32ml) was not significantly different from the ground truth (median 2.89ml, IQR 0.77-9.17ml) (P = 0.07); Bland-Altman curves showed that the core volume of iStroke and RAPID software were comparable with each other on individual agreement with ground truth. The hypoperfusion volume and mismatch volume on iStroke were not statistically different from those on the RAPID software, respectively. In patients with large vessel occlusion (n = 74), the agreement between iStroke and RAPID was substantial (kappa = 0.76) according to DEFUSE 3 criteria (infarct core < 70ml, mismatch volume ≥ 15ml, and mismatch ratio ≥ 1.8). The iStroke automatic processing of ADC and PWI is a reliable software for the identification of diffusion-perfusion mismatch in acute ischemic stroke.

Effect of Nursing Intervention on Self-Management and Quality of Life in Patients with Chronic Kidney Disease Evaluated by Renal Diffusion Tensor Imaging Features Using Image Registration Algorithm

The aim of this research was to explore the effect of nursing intervention on self-management and quality of life in patients with chronic kidney disease (CKD) by using the renal diffusion tensor imaging (DTI) feature of image registration algorithm. A total of 100 patients with CKD were randomly divided into experimental group (nursing maintenance guidance intervention) and control group (routine nursing), with 50 cases in each group. The image effect before and after registration, self-management behavior after 6 months, quality of life, DTI-related parameters, and renal function indicators were collected and analyzed. The results showed that the images were clearer than those before registration, the self-management ability in the control group (92.81 ± 19.32) was smaller than that in the experimental group (107.12 ± 18.78), the quality of life in the experimental group (121.47 ± 11.21) was greater than that in the control group (104.89 ± 12.11), and the corresponding magnetic resonance apparent diffusion coefficient (ADC) (2.54 ± 0.28) and fractional anisotropy (FA) (0.28 ± 0.07) in the cortex were greater than those in the control group (2.35 ± 0.21, 0.23 ± 0.04). The differences were statistically significant ( P &lt; 0.05 ). The corresponding ADC value (2.32 ± 0.22) and FA value (0.59 ± 0.02) of medulla were greater than those of the control group (2.12 ± 0.24 and 0.41 ± 0.17). The levels of serum creatinine (Scr) (μmol/L) (421.38 ± 42.78) and 24 h urinary protein (24 h-Upro) (mg/d) (1,836.7 ± 545.98) were lower than those of the control group, and the differences had statistical significance ( P &lt; 0.05 ). In summary, the registration algorithm can enhance the effect of image presentation and nursing intervention has positive significance for the self-management and quality of life of patients with CKD.

Apparent diffusion coefficient magnetic resonance imaging (ADC-MRI) in the axillary breast cancer lymph node metastasis detection: a narrative review.

The presence of axillary lymph nodes metastases in breast cancer is the most significant prognostic factor, with a great impact on morbidity, disease-related survival and management of oncological therapies; for this reason, adequate imaging evaluation is strictly necessary. Physical examination is not enough sensitive to assess breast cancer nodal status; axillary ultrasonography (US) is commonly used to detect suspected or occult nodal metastasis, providing exclusively morphological evaluation, with low sensitivity and positive predictive value. Currently, sentinel lymph node biopsy (SLNB) and/or axillary dissection are the milestone for the diagnostic assessment of axillary lymph node metastases, although its related morbidity. The impact of magnetic resonance imaging (MRI) in the detection of nodal metastases has been widely investigated, as it continues to represent the most promising imaging modality in the breast cancer management. In particular, diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values represent additional reliable non-contrast sequences, able to improve the diagnostic accuracy of breast cancer MRI evaluation. Several studies largely demonstrated the usefulness of implementing DWI/ADC MRI in the characterization of breast lesions. Herein, in the light of our clinical experience, we perform a review of the literature regarding the diagnostic performance and accuracy of ADC value as potential pre-operative tool to define metastatic involvement of nodal structures in breast cancer patients. For the purpose of this review, PubMed, Web of Science, and SCOPUS electronic databases were searched with different combinations of "axillary lymph node", "breast cancer", "MRI/ADC", "breast MRI" keywords. All original articles, reviews and metanalyses were included.

Pituitary macroadenoma: Accuracy of apparent diffusion coefficient magnetic resonance imaging in grading tumor aggressiveness.

The purpose of this study is to evaluate the accuracy of apparent diffusion coefficient magnetic resonance imaging in grading tumor aggressiveness using histogram apparent diffusion coefficient values. Eighteen patients with surgically proved pituitary macroadenomas were included in this study. Diffusion-weighted imaging with single-shot echo-planar sequence at 3-T with a 32-channel head coil was performed with b values of 0 and 1000 s/mm2. Calculated apparent diffusion coefficient maps were generated, and a 3-D volume of interest was placed on the tumor while superimposing contrast-enhanced magnetic resonance images. All apparent diffusion coefficient values within the volume of interest were used to compute the average apparent diffusion coefficient of the tumor. The apparent diffusion coefficient values were binned to construct the apparent diffusion coefficient histogram. Using the histogram, the mean, percentiles, skewness, and kurtosis of the apparent diffusion coefficient of the entire tumor were computed. Apparent diffusion coefficient histogram parameters were compared with the MIB-1 index, invasiveness, and recurrence for grading tumor aggressiveness of pituitary adenomas. The skewness of the apparent diffusion coefficient histogram only showed significant differences among MIB-1 indices ( p = 0.030). All apparent diffusion coefficient histogram parameters showed no significant differences between negative and positive invasion. The skewness and kurtosis of the apparent diffusion coefficient histogram showed significant differences between positive and negative recurrence (skewness p = 0.011, kurtosis p = 0.011). Receiver-operating characteristics analysis between positive and negative recurrence showed that both skewness and kurtosis of the apparent diffusion coefficient achieved area under the curve at 0.967. Skewness and kurtosis of the apparent diffusion coefficient histogram were the predictive parameters for assessing tumor proliferative potential and recurrence of pituitary adenomas.

OA047] Robust radiomic feature selection in magnetic resonance apparent diffusion coefficient maps of rectal cancer

Purpose Changes in Apparent Diffusion Coefficient (ADC) intensities derived from Magnetic Resonance (MR) imaging have been shown to be potentially predictive of (chemo) radiotherapy response in rectal cancer. Radiomics is a non-invasive, computer-assisted extraction of image-based biomarkers that assist in characterization of tumour phenotype. This study concerns the identification and selection of robust (i.e. repeatable and reproducible) radiomic features in MR-ADC across independent scanners in The Netherlands and Denmark. Methods Retrospective datasets (23 cases from the THUNDER clinical trial and 34 cases from a Danish watchful-waiting protocol) were independently manually delineated. Radiomic features were extracted using public open source software. Repeatability was examined by test-retest using scans 5 min apart. Reproducibility was assessed using concordance and intra-class correlation coefficients for sensitivity to inter-observer disagreement, image re-processing and effect of image filters. Results Significant intra-class correlations were observed between related sets of features. Histogram-based features were least sensitive to variations with respect to resampling and quantization (78% and 89% of features, respectively, exceeding the highest reproducibility criterion). Global robustness was adversely affected by image filtering and differences in manual delineation. Shape metrics were highly sensitive to inter-observer variability, but were insensitive to differences in image pre-processing. Textural features exhibited the highest sensitivity to processing steps, for all of the examined options. A number of radiomic features were found to be correlated with tumour volume, which should be a noted as a potential confounder for future radiomics studies. Conclusions This study showed that radiomic features were differentially affected by specific choices made along the processing pathway. In general, histogram features were least sensitive to details of processing, while shape metrics and textural features are more susceptible to heterogeneity in delineation, slice thickness and filtration. The latter was most likely due to its reliance on subtly nuanced properties within the image. Identification and selection of robust radiomic metrics are essential for development of clinically actionable prognostic models for rectal cancer incorporating image-based biomarkers.

Proton Therapy for Juvenile Pilocytic Astrocytoma: Quantifying Treatment Responses by Magnetic Resonance Diffusion Tensor Imaging.

Proton therapy is increasingly used to treat pediatric brain tumors. However, the response of both tumors and healthy tissues to proton therapy is currently under investigation. One way of assessing this response is magnetic resonance (MR) diffusion tensor imaging (DTI), which can measure molecular mobility at the cellular level, quantified by the apparent diffusion coefficient (ADC). In addition, DTI may reveal axonal fiber directional information in white matter, quantified by fractional anisotropy (FA). Here we report use of DTI to assess tumor and unexposed healthy brain tissue responses in a child who received proton therapy for juvenile pilocytic astrocytoma. A 10-year-old boy with recurrent juvenile pilocytic astrocytoma of the left thalamus received proton therapy to a dose of 50.4Gy (RBE) in 28 fractions. Functional magnetic resonance imaging was used to select beam angles for treatment planning. Over the course of the 7-year follow-up period, magnetic resonance imaging including DTI was done to assess response. The MR images were registered to the treatment-planning computed tomography scan, and the gross tumor volume (GTV) was mapped onto the MR images at each follow-up. The GTV contour was then mirrored to the right side of brain through the midline to represent unexposed healthy brain tissue. Proton therapy delivered the full prescribed dose to the target while completely sparing the contralateral brain. The MR ADC images obtained before and after proton therapy showed that enhancement corresponding to the GTV had nearly disappeared by 25 months. The ADC and FA measurements confirmed that contralateral healthy brain tissue was not affected, and the GTV reverted to clinically normal ADC and FA values. Use of DTI allowed quantitative evaluation of tumor and healthy brain tissue responses to proton therapy.

Prediction of Infarct Lesion Volumes by Processing Magnetic Resonance Apparent Diffusion Coefficient Maps in Patients with Acute Ischemic Stroke

We aimed to investigate the diagnostic value of apparent diffusion coefficient (ADC) maps in magnetic resonance imaging (MRI) in the volume of acute cerebral infarction (ACI). A total of 207 ACI patients were selected in our study. The cerebral infarction (CI) volume in the initial diffusion-weighted imaging examination, minimum ADC value, relative apparent diffusion coefficient (rADC) value, and mean ADC value were measured. The correlations between age, smoking, drinking, hypertension, diabetes, coronary heart disease, clinical stage, the lowest ADC value, the mean ADC value, and the mean rADC value with CI volume were analyzed by logistic regression analysis. A receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of the ADC value in the ACI volume. There was a significant difference in the distribution of the CI volume in ACI patients (P <.05). A significant difference was found in the signal intensity and percentage distribution of ADC map in patients of different CI groups with different CI volumes (P <.05). The signal of the ADC map was positively correlated with the CI volume. The mean ADC and rADC values had significant differences between different CI volumes (all P <.05). Logistic regression analysis revealed that the mean ADC value was significantly correlated with the CI volume (P <.05). Analysis of the ROC curve showed that the quantitative value of ADC has a diagnostic value for the ACI volume. This study has shown that the signal intensity change on the ADC map in MRI and quantitative analysis of the ADC value can be used as a reference for predicting the ACI volume.

Evaluation of the treatment response to neoadjuvant chemotherapy in locally advanced breast cancer using combined magnetic resonance vascular maps and apparent diffusion coefficient.

To evaluate the treatment response of locally advanced breast cancer (LABC) to neoadjuvant chemotherapy using magnetic resonance (MR) vascular maps and apparent diffusion coefficient (ADC) at 3T. Materials and Methods Thirty-one patients with LABC who underwent breast MR studies before, after the first course, and after completing neoadjuvant chemotherapy were enrolled. Vascular morphology was retrieved via Hessian matrix and the voxels of the vessels and volume of vessels were measured automatically. Whole tumor mean ADC values were calculated. Clinical responders were defined as >50% tumor reduction in the final MR studies. Pathologically complete responders were also recorded. There were 21 clinical responders and 10 nonresponders. Compared to the nonresponders after the first course, the responders were characterized by more vascular reduction of the breast lesion and decreased bilateral vascular discrepancy (voxels and volume), and increments in the ADC value and ADC percentage of the lesions (all P < 0.05). There were three pathological complete responders who showed more apparent early vascular reduction of the lesion breast (voxels and volume) and increments in the ADC value than others (P = 0.02, 0.01 and 0.02, respectively). The early changes of MR vascular maps and ADC are associated with the final treatment response of LABC.

Diffusion-weighted MR imaging of normal and abnormal scrotum: preliminary results

Magnetic resonance (MR) imaging of the scrotum represents an important supplemental diagnostic tool in the evaluation of scrotal diseases. Diffusion-weighted (DW) MR imaging is a developing technique, proved to improve tissue characterization. We evaluated the feasibility and diagnostic performance of DW MR imaging in the detection and characterization of scrotal lesions. We retrospectively evaluated 31 scrotal lesions (23 intratesticular and 8 extratesticular) in 26 men. All MR examinations were performed on a 1.5-T unit, using a pelvic-phased array coil. DW sequences were obtained using a single shot, multislice spin echo planar diffusion pulse sequence and a b factor of 0 and 900 s mm(-2). The DW MR characteristics and the apparent diffusion coefficient (ADC) values of normal scrotal contents and scrotal diseases were evaluated. Comparison between the ADC values of normal scrotum, benign lesions and scrotal malignancies was performed. The accuracy of conventional sequences, DW images alone and DW imaging combined with conventional images in differentiating benign from malignant scrotal lesions was calculated. The ADC values of testicular malignancies were different from those of normal testis and benign intratesticular lesions, and the ADC values of benign extratesticular lesions from those of normal epididymis (P<0.05). The overall accuracy of conventional imaging, DW imaging alone and DW MR combined with conventional sequences in the characterization of intratesticular lesions was 91%, 87% and 100%, respectively. Our findings suggest that DW MR imaging and ADC values may provide valuable information in the diagnosis and characterization of scrotal diseases.

Apparent diffusion coefficient correlation with oesophageal tumour stroma and angiogenesis

Because diffusion-weighted imaging (DWI) can predict the prognosis of patients with oesophageal squamous cell carcinoma (ESCC), we hypothesised that apparent diffusion coefficient (ADC) values might be correlated with the collagen content and tumour angiogenesis. The purpose of this study was to determine the correlation between ADC values of ESCC before treatment and oesophageal tumour stroma and angiogenesis. Seventeen patients with ESCC were enrolled. The ADC values were calculated from the DWI score. Seventeen patients who had undergone oesophagectomy were analysed for tumour stroma, vascular endothelial growth factor (VEGF) and CD34. Tissue collagen was stained with azocarmine and aniline blue to quantitatively analyse the extracellular matrix in cancer stroma. Tissues were stained with VEGF and CD34 to analyse the angiogenesis. The ADC values decreased with stromal collagen growth. We found a negative correlation between the tumour ADC and the amount of stromal collagen (r = -0.729, P = 0.001), i.e. the ADC values decreased with growth of VEGF. We also found a negative correlation between the ADC of the tumours and the amount of VEGF (r = 0.538, P = 0.026). Our results indicated that the ADC value may be a novel prognostic factor and contribute to the treatment of oesophageal cancer. • Magnetic resonance apparent diffusion coefficient values inversely indicate tumour stromal collagen • There is also negative correlation between ADCs and vascular endothelial growth factor • ADC values may contribute to the treatment of oesophageal cancer.

Rectal Cancer: Assessment of Complete Response to Preoperative Combined Radiation Therapy with Chemotherapy—Conventional MR Volumetry versus Diffusion-weighted MR Imaging

To determine diagnostic performance of diffusion-weighted (DW) magnetic resonance (MR) imaging for assessment of complete tumor response (CR) after combined radiation therapy with chemotherapy (CRT) in patients with locally advanced rectal cancer (LARC) by means of volumetric signal intensity measurements and apparent diffusion coefficient (ADC) measurements and to compare the performance of DW imaging with that of T2-weighted MR volumetry. A retrospective analysis of 50 patients with LARC, for whom clinical and imaging data were retrieved from a previous imaging study approved by the local institutional ethical committee and for which all patients provided informed consent, was conducted. Patients underwent pre- and post-CRT standard T2-weighted MR and DW MR. Two independent readers placed free-hand regions of interest (ROIs) in each tumor-containing section on both data sets to determine pre- and post-CRT tumor volumes and tumor volume reduction rates (volume). ROIs were copied to an ADC map to calculate tumor ADCs. Histopathologic findings were the standard of reference. Receiver operating characteristic (ROC) curves were generated to compare performance of T2-weighted and DW MR volumetry and ADC. The intraclass correlation coefficient (ICC) was used to evaluate interobserver variability and the correlation between T2-weighted and DW MR volumetry. Areas under the ROC curve (AUCs) for identification of a CR that was based on pre-CRT volume, post-CRT volume, and volume, respectively, were 0.57, 0.70, and 0.84 for T2-weighted MR versus 0.63, 0.93, and 0.92 for DW MR volumetry (P = .15, .02, .42). Pre- and post-CRT ADC and ADC AUCs were 0.55, 0.54, and 0.51, respectively. Interobserver agreement was excellent for all pre-CRT measurements (ICC, 0.91-0.96) versus good (ICC, 0.61-0.79) for post-CRT measurements. ICC between T2-weighted and DW MR volumetry was excellent (0.97) for pre-CRT measurements versus fair (0.25) for post-CRT measurements. Post-CRT DW MR volumetry provided high diagnostic performance in assessing CR and was significantly more accurate than T2-weighted MR volumetry. Post-CRT DW MR was equally as accurate as volume measurements of both T2-weighted and DW MR. Pre-CRT volumetry and ADC were not reliable.

The utility of diffusion-weighted MR imaging for differentiating uterine sarcomas from benign leiomyomas

The usefulness of diffusion-weighted (DW) magnetic resonance (MR) imaging for the diagnosis of uterine sarcomas was investigated, as well as whether DW images and quantitative measurement of apparent diffusion coefficient (ADC) values can facilitate differentiating uterine sarcomas from benign leiomyomas. MR images including DW images were obtained in 43 surgically treated patients with 58 myometrial tumors, including seven uterine sarcomas (five leiomyosarcomas and two endometrial stromal sarcomas) and 51 benign leiomyomas (43 ordinary leiomyomas, two cellular leiomyomas and six degenerated leiomyomas). Qualitative analysis of non-enhanced and postcontrast MR images and DW images and quantitative measurement of ADC values were performed for each myometrial tumor. Both uterine sarcomas and cellular leiomyomas exhibited high signal intensity on DW images, whereas ordinary leiomyomas and most degenerated leiomyomas showed low signal intensity. The mean ADC value (10(-3) mm(2)/s) of sarcomas was 1.17 +/- 0.15, which was lower than those of the normal myometrium (1.62 +/- 0.11) and degenerated leiomyomas (1.70 +/- 0.11) without any overlap; however, they were overlapped with those of ordinary leiomyomas and cellular leiomyomas. In addition to morphological features on nonenhanced and postcontrast MR sequences, DW imaging and ADC measurement may have a potential ability to differentiate uterine sarcomas from benign leiomyomas.

Glioblastoma multiforme with diffusion-weighted magnetic resonance imaging characteristics mimicking primary brain lymphoma

The authors report on the first case of corpus callosum glioblastoma multiforme (GBM) with diffusion-weighted (DW) magnetic resonance (MR) imaging findings that mimicked those for lymphoma but with MR spectroscopy results absent of lymphoma characteristics. This 68-year-old man presented with rapid, progressive impairment in short-term memory as well as slow responses and a change in his personality within 3 weeks of admission. Results of cranial computed tomography revealed a slightly hyperdense corpus callosum tumor with bihemispheric involvement. Magnetic resonance images showed a homogeneous mass with strong enhancement. The mass showed water restriction on DW MR images and apparent diffusion coefficient (ADC) maps but no markedly elevated lipid resonance on MR spectroscopy. The patient underwent tumor resection. Results of pathological studies with immunohistochemical analysis confirmed that the lesion was GBM. Diffusion-weighted MR imaging together with ADC mapping and MR spectroscopy was reported to be useful in differentiating GBM and primary brain lymphoma. The lymphomas were hyperintense to gray matter on DW MR images and isointense to hypointense on ADC maps because of water restriction. In contrast, the GBMs were hyperintense to gray matter on both DW MR images and ADC maps because of the T2 shine-through effect. On MR spectroscopy, lipid resonance was markedly elevated in lymphoma but only slightly elevated in GBM.

Congenital Muscular Dystrophy with Merosin Deficiency:1H MR Spectroscopy and Diffusion-weighted MR Imaging

To prospectively use hydrogen 1 ((1)H) magnetic resonance (MR) spectroscopy and apparent diffusion coefficient (ADC) maps to try to explain the discrepancy between the extensive white matter (WM) abnormalities observed at MR imaging and the relatively mild neurocognitive decline in patients with merosin-deficient congenital muscular dystrophy (CMD). The hospital ethics committee approved this study, and informed consent was obtained. Nine patients (five boys, four girls; age range, 3-9 years; mean, 6 years +/- 2 [standard deviation]) with merosin-deficient CMD underwent T1-weighted, T2-weighted, fluid-attenuated inversion recovery, and diffusion-weighted MR imaging and (1)H MR spectroscopy, which was performed in the parieto-occipital WM (POWM) and frontal WM (FWM) by using stimulated-echo acquisition mode. Metabolite (N-acetylaspartate [NAA], choline-containing compounds [Cho], and myo-inositol [mI]) ratios were calculated in relation to creatine/phosphocreatine (Cr) and water (H(2)O). NAA/Cho was also calculated. ADCs were calculated in approximately the same locations that were studied with spectroscopy. For comparison, (1)H MR spectroscopy (n = 10) and ADC mapping (n = 7) were also performed in 10 healthy age- and sex-matched control subjects (three boys, seven girls; age range, 4-9 years; mean, 6 years +/- 1). Statistical analysis involved the t test for comparison between different groups; correlation between ADC and spectroscopy results was studied with the Pearson test. MR imaging revealed evidence of bilateral WM involvement in all patients. Whereas their NAA/Cr and Cho/Cr were normal, their mI/Cr was slightly increased compared with that in control subjects (P = .03 in FWM and P = .07 in POWM), and their NAA/Cho was decreased in POWM (P = .03). NAA/H(2)O, Cr/H(2)O, Cho/H(2)O, and mI/H(2)O were considerably decreased (P < .05 for all) and ADC values were increased (P < .001) in WM in all patients versus these values in WM in control subjects. There was significant correlation between ADC values and metabolite/water ratios (r = -0.777 to -0.967, P < .05). ADC mapping and (1)H MR spectroscopy reveal abnormally high free-water concentrations in the WM of patients with merosin-deficient CMD.