[Brain gray matter abnormalities revealed by voxel-based morphometry in patients with chronic low back pain].

OBJECTIVE: To explore the morphometric abnormalities of brain gray matter (GM) in patients with chronic low back pain (CLBP). METHODS: Thirty patients with CLBP and 30 healthy individuals were enrolled and examined with a 3.0 T magnetic resonance (MR) scanner. High-resolution T1 structural MR data were acquired and data analysis was performed using voxel-based morphometry (VBM) in FMRIB Software Library. The morphological differences were compared between the two groups. RESULTS: s Compared with the healthy control subjects, patients with CLBP showed decreased GM volumes in several brain cortical areas including the bilateral superior frontal gyrus, right frontal pole, left insular cortex, left middle and left inferior temporal gyrus (P<0.05, after TFCE correction). Increased GM volumes were found in the patients in the subcortical structures including the left thalamus, bilateral putamen, bilateral nucleus accumben and right caudate nucleus (P<0.05, after TFCE correction). CONCLUSION: Patients with CLBP have different patterns of GM abnormalities in different brain regions, characterized by reduced GM volume in cerebral cortical regions and increased GM volume in the subcortical nuclei. Such changes might be associated with the maladaptation of the brain in chronic pain state.

Abnormal Subcortical Brain Morphology in Patients with Knee Osteoarthritis: A Cross-sectional Study.

Despite the involvement of subcortical brain structures in the pathogenesis of chronic pain and persistent pain as the defining symptom of knee osteoarthritis (KOA), little attention has been paid to the morphometric measurements of these subcortical nuclei in patients with KOA. The purpose of this study is to explore the potential morphological abnormalities of subcortical brain structures in patients with KOA as compared to the healthy control subjects by using high-resolution MRI. Structural MR data were acquired from 26 patients with KOA and 31 demographically similar healthy individuals. The MR data were analyzed by using FMRIB's integrated registration and segmentation tool. Both volumetric analysis and surface-based shape analysis were performed to characterize the subcortical morphology. The normalized volumes of bilateral caudate nucleus were significantly smaller in the KOA group than in the control group (P = 0.004). There was also a trend toward smaller volume of the hippocampus in KOA as compared to the control group (P = 0.027). Detailed surface analyses further localized these differences with a greater involvement of the left hemisphere (P < 0.05, corrected) for the caudate nucleus. Hemispheric asymmetry (right larger than left) of the caudate nucleus was found in both KOA and control groups. Besides, no significant correlation was found between the structural data and pain intensities. Our results indicated that patients with KOA had statistically significant smaller normalized volumes of bilateral caudate nucleus and a trend toward smaller volume of the hippocampus as compared to the control subjects. Further investigations are necessary to characterize the role of caudate nucleus in the course of chronicity of pain associated with KOA.

Diffusion tensor imaging of optic nerve and optic radiation in primary chronic angle-closure glaucoma using 3T magnetic resonance imaging.

AIM: To evaluate the value of quantitative diffusion tensor imaging (DTI) in assessing the axonal and myelin damage of the optic nerves and optic radiations in patients with chronic primary angle-closure glaucoma (PACG) by using high-field magnetic resonance (MR) imaging (3T). METHODS: Twenty patients with bilateral chronic PACG and twenty age- and sex matched disease-free control subjects were enrolled. Conventional MRI and DTI were performed on all subjects using 3T MR scanner. Mean diffusivity (MD), fractional anisotropy (FA), axial diffusivities (AD) and radial diffusivities (RD) of each optic nerve and each optic radiation were measured by using post-processing software of DTI studio 2.3, and then compared between left eyes and right eyes and between patients group and control group. The paired-sample t- test were used. RESULTS: There was no abnormality in the shape and signal intensity of the optic nerves and optic radiations in patients group and control group on the conventional MRI. No significant differences were observed in the FA, MD, AD and RD between the right and left optic nerves and optic radiations within patients group and control group (P>0.05). The optic nerves and optic radiations of patients with chronic PACG, as compared with control subjects, had significantly higher MD, AD, RD and significantly lower FA (P<0.05). CONCLUSION: The diffusivity of optic nerves and optic radiations in chronic PACG group showed abnormal and diffusivity parameters could be used markers of axonal and myelin injury in glaucoma.

Timing of diffusion tensor imaging in the acute spinal cord injury of rats.

The aim of this study was to evaluate the characteristics of magnetic resonance diffusion tensor imaging (DTI) in acute spinal cord following a thoracic spinal cord injury (SCI), and to determine the optimal time of examination. Sprague-Dawley rats were used as experimental animals and contusion injuries were made at the T10 vertebral level. The rats were divided into control, mild injury, moderate injury, and severe injury groups. Spinal magnetic resonance DTI was scheduled at 6, 24 and 72 hours (h) post-SCI, and the DTI parameters such as fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated, and the diffusion tensor tractography (DTT) of the spinal cord was also generated. We observed a significant decrease of FA in all the three injured groups, and the FA at 24 h post-SCI exhibited the greatest decrease among different set times. For ADC, only the group of severely injured rats saw a significant decrease at 24 and 72 h compared with the control group. DTT showed interruption of nerve fiber tracking in the injured groups. This study demonstrates that FA can differentiate various grades of SCI in the early stage, and 24 h after injury might be the optimal time for identifying injury severity.

Magnetic resonance diffusion tensor imaging of optic nerve and optic radiation in healthy adults at 3T.

AIM: To investigate the diffusion characteristics of water of optic nerve and optic radiation in healthy adults and its related factors by diffusion tensor imaging (DTI) at 3T. METHODS: A total of 107 healthy volunteers performed head conventional MRI and bilateral optic nerve and optic radiation DTI. The primary data of DTI was processed by post-processing software of DTI studio 2.3, obtaining fractional anisotropy value, mean diffusivity value, principal engine value, orthogonal engine value by measuring, and analyzed by the SPSS13.0 statistical software. RESULTS: The bilateral optic nerve and optic radiation fibers presented green color in directional encoded color (DEC) maps and presented high signal in fractional anisotropy (FA) maps. The FA value of the left optic nerve was 0.598±0.069 and the right was 0.593±0.065; the mean diffusivity (MD) value of the left optic nerve was (1.324±0.349)×10(-3)mm(2)/s and the right was (1.312±0.350)×10(-3)mm(2)/s; the principal engine value (λ‖) of the left optic nerve was (2.297±0.522)×10(-3)mm(2)/s and the right was (2.277±0.526)×10(-3)mm(2)/s; the orthogonal engine value (λ⊥) of the left optic nerve was (0.838±0.285)×10(-3)mm(2)/s and the right was (0.830±0.280)×10(-3)mm(2)/s; the FA value of the left optic radiation was 0.636±0.057 and the right was 0.628±0.056; the mean diffusivity (MD) value of the left optic radiation was (0.907±0.103)×10(-3)mm(2)/s and the right was (0.889±0.125)×10(-3)mm(2)/s; the principal eigenvalue (λ‖) of the left optic radiation was (1.655±0.210)×10(-3)mm(2)/s and the right was (1.614±0.171)×10(-3)mm(2)/s; the orthogonal enginvalue (λ⊥) of the left optic radiation was (0.531±0.103)×10(-3)mm(2)/s and the right was (0.524±0.152)×10(-3)mm(2)/s. There was no obvious difference between the FA, MD, λ‖, λ⊥ of the bilateral optic radiation and the bilateral optic nerve (P>0.05) and no obvious difference between male and female group. The FA, MD, λ‖, λ⊥ of the bilateral optic radiation and the bilateral optic nerve had no obvious correlations to the age. CONCLUSION: DTI is sensitive to the optic nerve and radiation and the relevant DTI parameters of the optic nerve and radiation are established preliminarily in this study.

[Diffusion characteristics of subcortical structures in patients with subcortical ischemic vascular disease and its correlation to cognitive function].

OBJECTIVE: To explore the diffusion-tensor imaging (DTI) characteristics of normal-appearing white matter (NAWM) and normal-appearing gray matter (NAGM) on conventional magnetic resonance imaging (MRI) in patients with subcortical ischemic vascular disease (SIVD) and examine the relation of such features with the general cognitive function of the patients. METHODS: DTI was performed in 46 SIVD patients and 34 age-matched control subjects with normal MRI findings. The apprarent diffusion coeeficient (ADC) and fractional anisotropy (FA) were measured within the regions of white matter lesions (WMLs), NAWM and NAGM. All the subjects were examined by neurologists with MMSE and clinical neurologic examination. RESULTS: Compared with normal controls, SIVD subjects showed increased ADC values in the subcortical NAGM and NAWM in anterior periventricular and centrum semiovale, with decreased FA values in the caudate nucleus, thalamus and centrum semiovale. An increased severity of the WMLs was associated with increased ADC and decreased FA in the NAWM of SIVD patients. After controlling for age, the ADC in the NAWM of the posterior periventricular, NAWM and WMLs in the centrum semiovale, caudate nucleus and thalamus showed significant inverse correlations to MMSE; FA values in NAWM of the anterior periventricular and WMLs of the centrum semiovale were positively correlated to MMSE. CONCLUSION: In SIVD patients, the NAWM and NAGM regions shown by MRI contain diffusion abnormalities, and these abnormalities shown by DTI are significantly correlated to the general cognitive function of the patients.

Meta-analysis of quantitative diffusion-weighted MR imaging in the differential diagnosis of breast lesions.

BACKGROUND: To determine, in a meta-analysis, the diagnostic performance of quantitative diffusion-weighted (DW) MR imaging in patients with breast lesions. METHODS: English and Chinese studies published prior to June 2009 to assess the diagnostic performance of quantitative DWI in patients with breast lesions were reviewed and summarized with reference to the inclusion and exclusion criteria. Methodological quality was assessed by using the quality assessment of diagnostic studies (QUADAS) instrument. Publication bias analysis was performed by using Comprehensive Meta-analysis version 2. Meta-Disc version 1.4 was used to describe primary results and explore homogeneity by Chi-square test and inconsistency index; to explore threshold effect by receiver operator characteristic (ROC) space and Spearman correlation coefficient; and to pool weighted sensitivity and specificity by fixed or random effect model. A summary ROC (sROC) curve was constructed to calculate the area under the curve (AUC). RESULTS: Of 65 eligible studies, 13 with 615 malignant and 349 benign lesions were included in the original meta-analysis, among which heterogeneity arising from factors other than threshold effect and publication bias was explored. Methodological quality was moderate. The pooled weighted sensitivity and specificity with corresponding 95% confidence interval (CI) in one homogenous subgroup of studies using maximum b = 1000 s/mm2 were 0.84 (0.80, 0.87) and 0.84 (0.79, 0.88) respectively. AUC of sROC was 0.9085. Sensitivity analysis demonstrated that the pooled estimates were stable and reliable. CONCLUSIONS: Quantitative DWI has a higher specificity to differentiate between benign and malignant breast lesions compared to that of contrast-enhanced MRI. However, large scale randomized control trials (RCTs) are necessary to assess its clinical value because of disunified diffusion gradient factor b and diagnosis threshold.

Magnetic resonance imaging and mammographic appearance of dermatofibrosarcoma protuberans in a male breast: a case report and literature review.

INTRODUCTION: Dermatofibrosarcoma protuberans is a rare low-grade soft tissue neoplasm with trunk and extremities being the most common sites of involvement. We report a rare case of male breast with dermatofibrosarcoma protuberans and its imaging features. To our knowledge the imaging appearance of dermatofibrosarcoma protuberans of the breast has never been reported in the literature. CASE PRESENTATION: We report the imaging appearance of dermatofibrosarcoma protuberans on the breast of a 41-year-old Chinese man who initially presented with a palpable lump. A mammogram showed two lesions, one with well circumscribed and the other with an ill defined border, in his right breast. Conventional magnetic resonance imaging was performed and showed the well defined larger lesion with mild central hypointensity while the smaller lesion had an irregular border. Both lesions were well characterized on the fat-suppressed sequences. CONCLUSIONS: Dermatofibrosarcoma protuberans is a rare soft tissue sarcoma and its occurrence on the breast is even rarer. Mammography and magnetic resonance imaging can help in characterizing the lesion and localizing the lesion for further diagnostic evaluation and surgical planning.

Evaluation of liver functional reserve by combining D-sorbitol clearance rate and CT measured liver volume.

AIM: Our research attempted to evaluate the overall functional reserve of cirrhotic liver by combination of hepatic functional blood flow, liver volume, and Child-Pugh's classification, and to discuss its value of clinical application. METHODS: Ninety two patients with portal hypertension due to hepatic cirrhosis were investigated. All had a history of haematemesis and hematochezia, esophageal and gastric fundus varices, splenomegaly and hypersplenia. A 2-year follow-up was routinely performed and no one was lost. Twenty two healthy volunteers were used as control group. Blood and urine samples were collected 4 times before and after intravenous D-sorbitol infusion. The hepatic clearance (CL(H)) of D-sorbitol was then calculated according to enzymatic spectrophotometric method while the total blood flow (Q(TOTAL)) and intrahepatic shunt (R(INS)) were detected by multicolor Doppler ultrasound, and the liver volume was measured by spiral CT. Data were estimated by t-test, variance calculation and chi-squared test. The relationships between all these parameters and different groups were investigated according to Child-Pugh classification and postoperative complications respectively. RESULTS: Steady blood concentration was achieved 120 mins after D-sorbitol intravenous infusion, which was (0.358+/-0.064) mmol x L(-1) in cirrhotic group and (0.189+/-0.05) mmol x L(-1) in control group (P<0.01). CL(H) =(812.7+/-112.4) ml x min(-1), Q(TOTAL) =(1280.6+/-131.4) ml x min(-1), and R(INS) =(36.54+/-10.65) % in cirrhotic group and CL(H)=(1248.3+/-210.5) ml x min(-1), Q(TOTAL)=(1362.4+/-126.9) ml x min(-1), and R(INS)=(8.37+/-3.32) % in control group (P<0.01). The liver volume of cirrhotic group was 1057+/-249 cm(3), 851+/-148 cm(3) and 663+/-77 cm(3) in Child A, B and C group respectively with significant difference (P<0.001). The average volume of cirrhotic liver in Child B, C group was significantly reduced in comparison with that in control group (P<0.001). The patient, whose liver volume decreased by 40 % with the CLH below 600 ml x min(-1), would have a higher incidence of postoperative complications. There was no strict correspondent relationship between CL(H), liver volume and Child-Pugh's classification. CONCLUSION: The hepatic clearance of D-sorbitol, CT measured liver volume can be reliably used for the evaluation of hepatic functional blood flow and liver metabolic volume. Combined with the Child-Pugh's classification, it could be very useful for further understanding the liver functional reserve, therefore help determine reasonable therapeutic plan, choose surgical procedures and operating time.