OBJECTIVE: To validate the usefulness of a diffusional anisotropic capillary array phantom and to investigate the effects of diffusion tensor imaging (DTI) parameter changes on diffusion fractional anisotropy (FA) and apparent diffusion coefficient (ADC) using the phantom. MATERIALS AND METHODS: Diffusion tensor imaging of a capillary array phantom was performed with imaging parameter changes, including voxel size, number of sensitivity encoding (SENSE) factor, echo time (TE), number of signal acquisitions, b-value, and number of diffusion gradient directions (NDGD), one-at-a-time in a stepwise-incremental fashion. We repeated the entire series of DTI scans thrice. The coefficients of variation (CoV) were evaluated for FA and ADC, and the correlation between each MR imaging parameter and the corresponding FA and ADC was evaluated using Spearman's correlation analysis. RESULTS: The capillary array phantom CoVs of FA and ADC were 7.1% and 2.4%, respectively. There were significant correlations between FA and SENSE factor, TE, b-value, and NDGD, as well as significant correlations between ADC and SENSE factor, TE, and b-value. CONCLUSION: A capillary array phantom enables repeated measurements of FA and ADC. Both FA and ADC can vary when certain parameters are changed during diffusion experiments. We suggest that the capillary array phantom can be used for quality control in longitudinal or multicenter clinical studies.
Anisotropy ; Diffusion Magnetic Resonance Imaging/*instrumentation/*methods ; Diffusion Tensor Imaging/*instrumentation/*methods ; Humans ; *Phantoms, Imaging ; Research Design ; Signal-To-Noise Ratio

OBJECTIVETo evaluate the normal appearance of large field diffusion weighted imaging (DWI) on 3.0T magnetic resonance imaging (MRI).

METHODSTwenty healthy volunteers and thirty patients with benign prostate hyperplasia were included in this study. All patients were examined with large field DWI on 3.0T MRI. Normal tissue appearance was analyzed and apparent diffusion coefficient (ADC) of normal tissue with high signal intensity was measured. The ADC values of bilateral symmetrical tissue were also compared. The ADC values of intervertebral disks of healthy people younger than 50 years and exceeding 50 years were compared.

RESULTSSalivary gland, spleen, kidney, gallbladder, bladder, prostate, seminal vesicle, testis, intervertebral disk, liquid in articular cavity and lymph node showed high signal intensity on large field DWI, while lung, liver and bone showed hypo-signal intensity. The mean ADC values of partial hyperintensity tissue were as followed: parotid gland (1.088 +/- 0.114) x 10(-3) mm2/S, submaxillary gland (1.309 +/- 0.189) x 10(-3) mm2/s, kidney (1.909 +/- 0.143) x 10(-3) mm2/s, seminal vesicle (1.669 +/- 0.168) x 10(-3) mm2/s, testis (1.028 +/- 0.075) x 10(-3) mm2/s, spleen (0.963 +/- 0.108) x 10(-3) mm2/s, bladder (2.898 +/- 0.267) x 10(-3) mm2/s, prostate (1.448 +/- 0.132) x 10(-3) mm2/s, intervertebral disks (1.360 +/- 0.140) x 10(-3) mm2/s. No statistical significance was found between the ADC values of bilateral symmetrical tissues. The difference of ADC values of intervertebral disks of healthy people younger than 50 years [(1.372 +/- 0.142) x 10(-3) mm2/s] and exceeding 50 years [(1.344 +/- 0.134) x 10(-3) mm2/s] showed statistical significance (P = 0.040).

CONCLUSIONUnderstanding the high signal intensity of normal tissue on large field DWI may help to differentiate the normal tissues and abnormal ones.

Adult ; Aged ; Diffusion Magnetic Resonance Imaging ; instrumentation ; methods ; Female ; Humans ; Intervertebral Disc ; anatomy & histology ; pathology ; Male ; Middle Aged ; Prostatic Hyperplasia ; pathology ; Whole Body Imaging ; instrumentation ; methods

OBJECTIVETo evaluate the feasibility of whole body diffusion weighted imaging (DWI) in bone metastasis detection using bone scintigraphy as comparison.

METHODSForty-five patients with malignancy history were enrolled in our study. All the patients received the whole body DWI and bone scintigraphy scan within 1 week. The magnetic resonance (MR) examination was performed on 3.0T MR scanner using embedded body coil. The images were reviewed separately by two radiologists and two nuclear medicine physicians, who were blinded to the results of the other imaging modality. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the two techniques for detecting bone metastasis were analyzed.

RESULTSA total of 181 metastatic lesions in 77 regions of 34 patients were detected by whole body DWI, and 167 metastatic lesions in 76 regions of 31 patients were identified by bone scintigraphy. The patient-based sensitivity and PPV of whole body DWI and bone scintigraphy were similar (89.5% vs. 81.6%, 97.1% vs. 91.2%), whereas, the patient-based specificity and NPV of whole body DWI were obviously higher than those of bone scintigraphy (85.7% vs. 57.1%, 60.0% vs. 36.4%). Ten regions negative in scintigraphy but positive in whole body DWI, mainly located in spine, pelvis, and femur; nine regions only detected by scintigraphy, mainly located in skull, sternum, clavicle, and scapula. The region-based sensitivity and specificity of whole body DWI were slightly higher than those of bone scintigraphy (89.5% vs. 88.4%, 95.6% vs. 87.6%).

CONCLUSIONWhole body DWI reveals excellent concordance with bone scintigraphy regarding detection of bone metastasis, and the two techniques are complementary for each other.

Aged ; Bone Neoplasms ; diagnosis ; pathology ; secondary ; Diffusion Magnetic Resonance Imaging ; instrumentation ; methods ; Female ; Humans ; Male ; Middle Aged ; Predictive Value of Tests ; Radionuclide Imaging ; Sensitivity and Specificity ; Whole Body Imaging ; instrumentation ; methods

OBJECTIVE: To assess the relationship between apparent diffusion coefficient (ADC) values on diffusion-weighted magnetic resonance (MR) imaging and pathologic measures of a tumor using a prostate cancer xenograft model. MATERIALS AND METHODS: Eighteen athymic nude mice with 36 PC-3-induced tumors were sacrificed to obtain specimens immediately after MR imaging in order to compare the findings on MR images with those seen on pathological specimens. Using a high-field small-animal MR scanner, T1- and T2-weighted imaging and DW MR imaging was performed. Tumors were then processed for Hematoxylin and Eosin staining to evaluate tumor cellularity, intratumoral necrosis and immunostaining using antibodies directed against CD31 and vascular endothelial growth factor (VEGF) to determine the levels of microvessel density (MVD). Mean ADC values that were measured on the solid portion within each tumor were compared with tumor volume, cellularity, degree of necrosis, VEGF expression, and MVD in the corresponding section of the pathological specimen. RESULTS: Mean ADC values of the solid portion within the PC-3-induced high-grade tumors were significantly correlated with the degree of intratumoral necrosis (r = 0.63, p < 0.0001) and MVD (r = -0.44, p = 0.008) on pathologic slides. The ADC values were not significantly correlated with tumor cellularity, VEGF expression, or tumor volume in high-grade prostate cancer tissues. CONCLUSION: In the xenografted prostate cancer model, the ADC values of the solid portion of the tumors are significantly correlated with tumor necrosis and MVD of the pathologic specimens. The ADC values may be utilized as surrogate markers for the noninvasive assessment of tumor necrosis and MVD in high-grade prostate cancer.
Animals ; Diffusion Magnetic Resonance Imaging/instrumentation/*methods ; Male ; Mice ; Mice, Nude ; Prostatic Neoplasms/*pathology ; Transplantation, Heterologous ; Vascular Endothelial Growth Factor A/metabolism

OBJECTIVETo explore the diagnostic and differential value of diffusion weighted imaging (DWI) for prostate cancer.

METHODSIncluded in the study were 50 patients with prostatic diseases, including 19 cases of prostate cancer (PCa) and 31 cases of benign prostatic hyperplasia (BPH), and another 16 healthy volunteers were recruited as controls. All underwent DWI sequence on a 1.5T superconducting MRI system with an endorectal coil. The results from DWIs and apparent diffusion coefficient (ADC) maps were treated statistically.

RESULTSThe mean ADC value of the prostatic peripheral zone and the prostatic central gland of the 16 healthy volunteers were (170.23 +/- 37.39) x 10(-5) mm2/s and (127.84 +/- 17.93) x 10(-5) mm2/s, while those of the 31 BPH cases and 19 PCa cases were (175.21 +/- 64.86) x 10(-5) mm2/s and (104.23 +/- 26.15) x 10(-5) mm2/s, respectively. There were significant differences in the tissue types between any two groups after the treatment of one-way ANOVA, except between the groups of the peripheral zone and. BPH.

CONCLUSIONPCa shows specific DWI features that could be distinguished from those of the normal prostatic tissues and BPH. Therefore, DWI has an important clinical application value in the diagnosis and differentiation of PCa.

Adult ; Aged ; Diagnosis, Differential ; Diffusion Magnetic Resonance Imaging ; instrumentation ; methods ; Humans ; Male ; Middle Aged ; Prostate ; pathology ; Prostatic Neoplasms ; diagnosis ; Reproducibility of Results ; Sensitivity and Specificity

Rectal cancer is one of the common cancers which poses a threat to the health of mankind. In recent years. Multi-modality treatment strategies for locally advanced rectal cancer improve the treatment efficiency. Accurate prediction of the treatment response after the neoadjuvant chemoradiotherapy (CRT) can guide more suitable treatment strategy. MERCURY study proved the prognostic value of post-CRT standard morphologic MRI(T2-weighted) assessment of tumor regression grade(TRG), and MRI assessment of circumferential resection margin can guide the definitive surgery. Compared with standard morphologic MRI (T2-weighted), functional MRI, including diffusion weighted imaging (DWI) and dynamic contrast enhanced (DCE) MRI, has shown more promising results for the prediction of therapeutic response in rectal cancer. The addition of diffusion-weighted images to T2-weighted images improves the accuracy of restaging examinations for determination of complete pathologic responders. DCE can reflect the tumor micro-vascular environment, and the change of perfusion in response to treatment. These images have the potential to improve the accuracy of therapeutic response in rectal cancer.
Chemoradiotherapy ; statistics & numerical data ; Contrast Media ; Diffusion Magnetic Resonance Imaging ; statistics & numerical data ; Humans ; Magnetic Resonance Imaging ; methods ; statistics & numerical data ; Margins of Excision ; Neoadjuvant Therapy ; statistics & numerical data ; Neoplasm Staging ; instrumentation ; methods ; statistics & numerical data ; Prognosis ; Rectal Neoplasms ; blood supply ; diagnostic imaging ; pathology

OBJECTIVE: The aim of this study was to examine the incidence of ischemia during protected carotid artery stenting (CAS) as well as to compare the protective efficacy of the balloon and filter devices on diffusion-weighted MR imaging (DWI). MATERIALS AND METHODS: Seventy-one consecutive protected CAS procedures in 70 patients with a severe (> 70%) or symptomatic moderate (> 50%) carotid artery stenosis were examined. A balloon device (PercuSurge GuardWire) and a filter device (FilterWire EX/EZ, Emboshield) was used in 33 cases (CAS-B group) and 38 cases (CAS-F group) to prevent distal embolization, respectively. All the patients underwent DWI within seven days before and after the procedures. The number of new cerebral ischemic lesions on the post-procedural DWI were counted and divided into ipsilateral and contralateral lesions according to the relationship with the stenting side. RESULTS: New cerebral ischemic lesions were detected in 13 (39.4%) out of the 33 CAS-Bs and in 15 (39.5%) out of the 38 CAS-Fs. The mean number of total, ipsilateral and contralateral new cerebral ischemic lesion was 2.39, 1.67 and 0.73 in the CAS-B group and 2.11, 1.32 and 0.79 in the CAS-F group, respectively. No statistical differences were found between the two groups (p = 0.96, 0.74 and 0.65, respectively). The embolic complications encountered included two retinal infarctions and one hemiparesis in the CAS-B group (9.09%), and one retinal infarction, one hemiparesis and one ataxia in the CAS-F group (7.89%). There was a similar incidence of embolic complications in the two groups (p = 1.00). CONCLUSION: The type of distal protection device used such as a balloon and filter does not affect the incidence of cerebral embolization after protected CAS.
Adult ; Aged ; Aged, 80 and over ; *Balloon Occlusion ; Blood Vessel Prosthesis Implantation/*instrumentation ; Brain Ischemia/*pathology ; Carotid Stenosis/*surgery ; *Diffusion Magnetic Resonance Imaging ; Endarterectomy, Carotid/adverse effects/methods ; Female ; Humans ; Intracranial Embolism/prevention & control ; Male ; Middle Aged ; Paresis/etiology ; Retinal Artery Occlusion/etiology ; Severity of Illness Index ; *Stents