Parameter optimization for non-contrast-enhanced selective magnetic resonance portography imaging / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate subtraction images acquired with 3D true steady-state free-precession(SSFP)sequence combined with time-spatial labeling inversion pulse(T-SLIP)for selective and non-contrast-enhanced(non-CE)visualization of the portal venous system,and explore the optimization of this protocol.</p><p><b>METHODS</b>Totally 13 healthy volunteers were recruited.Respiratory-triggered 3D true SSFP sequences on a 1.5T MRI system combined with T-SLIP placed on the spleen and mesenteric area were performed.The portographic images were generated from the subtraction between the pulse on and off images.According to the difference in inversion time(TI)of T-SLIP,four image groups group A(TI of 1300 ms),group B(TI of 1100 ms),group C(TI of 900 ms)and group D(TI of 700 ms),were assigned and compared to detect the optimal TI for portography.For quantitative analysis,the signal intensity(SI)of left and right liver lobe,the large vessels as main,right and left portal vein(MPV,RPV and LPV,respectively)and small vessels as branches of segments four(P4),six(P6)and eight(P8)were measured.The relative SI of MPV,RPV and LPV,as well as P4,P6 and P8 were also compared.For qualitative evaluation,the quality score of visualization was also evaluated using a 4-point scale.One-Way ANOVA and LSD test were used for comparison of quantitative data,and Friedman signed rank test was used for comparison of qualitative scores.</p><p><b>RESULTS</b>In 52 sequences of 13 volunteers,the selective visualization of the portal vein was all successfully conducted.Quantitative evaluation showed significant increased SI at the left lobe between C and D groups and A and B groups(comparison of group C to group A and BP=0.004,0.011;comparison of group D to group A and BP=0.001,0.004),while relative SI of LPV of groups C and D were lower than groups A and B(comparison of group C to group A and BP=0.015,0.015;comparison of group D to group A and BP=0.000,0.000).The relative SI of MPV in group D were decreased than groups A(P=0.000),B(P=0.000),and C(P=0.019).There was no significant difference in relative SI of small vessels among four groups(P>0.05).The image score of portal vessels in four groups also showed no differences(P>0.05).</p><p><b>CONCLUSIONS</b>3D true SSFP scan with T-SLIP enabled selective non-CE visualization of the portal vein with digital subtraction method.A fixed TI of both 1300 and 1100 ms can be preferable.</p>

Voxel-based Relaxometry of transverse relaxation rate with gradient echo R2(*) in patients with multiple system atrophy / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the transverse relaxation rate with gradient echo R2(*) changes in patients with Parkinsonian variant of multiple system atrophy (MSA-P) with a voxel-based analysis of R2(*) map.</p><p><b>METHODS</b>Whole brain structural images and multi-echo T2(*) weighted image were acquired in 27 patients with probable MSA-P and 24 healthy individuals. R2(*) maps of the MSA-P were compared with the controls by voxel-based methods.</p><p><b>RESULT</b>Compared with the controls, MSA-P patients showed significant R2(*) decrease bilaterally in brain stem, cerebellar hemispheres, insular lobe, temporal lobes, caudate nucleus, and corpus callosum (P<0.005).</p><p><b>CONCLUSIONS</b>R2(*) can reveal the significant brain involvements of MSA-P. The introduction of gradient echo may increase the sensitivity, although the susceptible artifact may interfere the detection efficiency of R2(*).</p>

Clinical application of magnetic resonance imaging in preoperative evaluation of endometrial cancer / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the value of magnetic resonance imaging (MRI) in the preoperative assessment of endometrial cancer.</p><p><b>METHODS</b>Ninety-four patients with histopathologically confirmed endometrial carcinoma were retrospectively enrolled in this study. MRI findings were compared with the pathologic findings in all cases. The depth of myometrial invasion and lymph node metastasis were evaluated by T2 weighted imaging (T2WI) combined with contrast enhancement or diffusion weighted imaging (DWI).</p><p><b>RESULTS</b>Among these 94 patients,62 had no or superficial myometrial involvement and 32 cases had deep myometrial involvement. Meanwhile, 24 groups of metastatic lymph nodes and 164 groups of non-metastatic lymph nodes were detected. The accuracy, specificity, sensitivity, negative predictive value, and positive predictive value of T2WI combined with contrast enhancement in discriminating no/superficial myometrial involvement from deep myometrial involvement were 88.3%, 90.3%, 84.4%, 91.8%, and 81.8%, whereas those of T2WI combined with DWI were 81.9%, 87.1%, 71.9%, 85.7%, and 74.2%, respectively. The accuracy, specificity, sensitivity, negative predictive value, and positive predictive value of T2WI combined with contrast enhancement in identifying metastatic lymph nodes were 89.4%, 96.8%, 54.5%, 90.9%, and 78.3%, whereas those of T2WI combined with DWI were 91.5%, 95.5%, 72.7%, 94.3%, and 77.4%, respectively.</p><p><b>CONCLUSIONS</b>T2WI combined with contrast enhancement is superior to T2WI combined with DWI in evaluation of the depth of myometrial invasion. However, DWI is more sensitive in identifying lymph node metastasis than T2WI combined with contrast enhancement.</p>

Quantitative evaluation of extraocular muscle with high-field magnetic resonance in patients with Graves' ophthalmopathy with upper-lid retraction / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the feasibility of high-field magnetic resonance in measuring the thickness and width of extraocular muscles, calculate the ratio of thickness to width, and summarize the characters of the diameters and its ratio in patients with Graves' ophthalmopathy (GO) with upper-lid retraction.</p><p><b>METHODS</b>Sixteen GO patients with upper-lid retraction (GO group) and 14 healthy control group were enrolled in this study. All the patients underwent enhanced high-field magnetic resonance orbital scan. The thickness and width of extraocular muscles were measured on axial, coronal or oblique sagittal enhanced T1 weighted images. The ratio of thickness to width (R1) and width to thickness (R2) were calculated. The diameters or ratio was evaluated as enlarged when they were 2 standard deviation greater than mean values of extraocular muscle in healthy control.</p><p><b>RESULTS</b>The thickness of levator palpebrae superioris, medial rectus, and inferior rectus muscles in GO group were significantly larger than those in the control group (P=0.000, P=0.017, P=0.032, respectively. The width of superior oblique muscles in GO group was significantly larger than that in control group (P=0.000). The R1 values of levator palpebrae superioris, inferior rectus, medial rectus, and lateral rectus muscles in GO group were significant larger than those in the control group (P=0.000,P=0.037, P=0.019,P=0.032, respectively. The R2 value of superior oblique muscles was significant larger than that in the control group (P=0.027). Aslo in GO group, 32 extraocular muscles showed an increased thickness. 47% of thickened extraocular muscles had an increased R1.</p><p><b>CONCLUSIONS</b>Enhanced orbit imaging with high-field magnetic resonance is helpful in the quantitative assessment of the thickness and width of extraocular muscles. In GO patients, in addition to the levator palpebrae superioris muscles, some other extraocular muscles also becomes thicker. Moreover, the increased diameters of superior oblique muscles is mainly due to the increase of its width R1 and R2 values can reflect the thickness and width of extraocular muscles and their relationship.</p>

Effects of emodin on expression of cytokines induced by lipopolysaccharide in corneal fibroblasts / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the effects of emodin on expression of cytokines induced by lipopolysaccharide (LPS) in cultured human corneal fibroblasts in vitro.</p><p><b>METHODS</b>Primary human corneal fibroblasts of passages 4 were used in this research. Cells were treated with 10 microg/L LPS for 1, 2, 4, or 8 hours, which were pretreated with or without emodin for 30 minutes before LPS challenge. The degeneration of inhibitor of kappaB-alpha (I kappaB-alpha) and the effect of emodin on it were analyzed by Western blot analysis with a specific antibody. The cellular abundance of the mRNA of interleukin (IL)-6 and IL-8 from corneal fibroblasts under different conditions was determined by reverse transcriptase polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>Compared with cells without LPS treatment, I kappaB-alpha level significantly decreased in every time point after LPS challenge (P < 0.01). Emodin inhibited the LPS-induced degeneration of I kappaB-alpha by corneal fibroblasts in a dose-dependent manner (P < 0.05). Compared with cells without LPS treatment, the expressions of IL-6 and IL-8 mRNA significantly increased in every time point after LPS challenge (P < 0.01). At the same time, the expressions of the mRNA of IL-6 and IL-8 induced by LPS in corneal fibroblasts were also inhibited by emodin in a dose-dependent manner (P < 0.05).</p><p><b>CONCLUSION</b>Emodin can inhibit the expressions of IL-6 and IL-8 mRNA induced by LPS in corneal fibroblasts, which maybe via inhibiting the degeneration of I kappaB-alpha and suppressing the activation of nuclear factor-kappaB.</p>

Clinical application of body diffusion weighted MR imaging in the diagnosis and preoperative N staging of cervical cancer / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To evaluate the clinical impact of body diffusion weighted imaging (DWI) on the diagnosis and preoperative N staging of cervical cancer.</p><p><b>METHODS</b>Twenty-four patients (mean age 37.9 years old) with proved cervical cancer by cervical biopsy and 24 female patients with other suspected pelvic abnormalities received preoperative body DWI scan. Results of body DWI were compared with pathological findings. The apparent diffusion coefficient (ADC) values of normal cervix and different pathological types of cervical cancer were compared. ADC value of normal or inflammatory lymph nodes was also compared with that of metastatic ones. Student's t test was used for statistical analysis.</p><p><b>RESULTS</b>There were 5 adenocarcinomas and 19 epitheliomas showed with biopsy results, and DWI showed 21 cervical lesions out of them (87.5%). ADC values of the normal cervix (n = 24), epithelioma (n = 19), and adenocarcinoma (n = 5) were (1.73 +/- 0.31) x 10(-3), (0.88 +/- 0.22) x 10(-3), and (1.08 +/- 0.12) x 10(-3) mm2/s, respectively. Statistical analysis showed significant difference in ADC value between normal cervical tissue and either tumor tissues (both P < 0.01). In patients had lymphadenectomy (n = 24), totally 67 lymph nodes including 16 metastatic lymph nodes were pathologically analyzed, and DWI showed 66 (98.5%) out of them. ADC values of normal/inflammatory and metastatic lymph nodes were (1.07 +/- 0.16) x 10(-3) and (0.77 +/- 0.13) x 10(-3) mm2/s (P < 0.01). Receiver operating characteristic (ROC) curve of ADC value of metastatic lymph node showed that area under curve was 0.961.</p><p><b>CONCLUSIONS</b>ADC value in cervical carcinoma is lower than that in normal cervix, and ADC may have predictive value in subtype discrimination. ADC value may improve the preoperative characterization of lymph node metastasis. And at least abdominal and pelvic DWI scan is suggested for N staging evaluation in such patients.</p>

Application of whole body diffusion weighted MR imaging for diagnosis and staging of malignant lymphoma / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To evaluate the clinical impact of whole body diffusion weighted imaging (WB-DWI) on diagnosis and staging of malignant lymphoma.</p><p><b>METHODS</b>Thirty-one patients with suspected lymphadenopathy were enrolled. WB-DWI was performed by using short TI inversion recovery echo-planar imaging sequence with free breathing and built-in body coil. Axial T2-weighted imaging images of the same location were used as reference. The results of WB-DWI were compared with pathological results and other imaging modalities. The mean apparent diffusion coefficient (ADC) values of different kinds of lymph nodes were compared.</p><p><b>RESULTS</b>WB-DWI was positive in all 18 cases with lymphoma, 5 cases with metastatic lymph nodes and 4 of 8 cases with benign lymphadenopathy. The mean ADC value of lymphomatous, metastatic and benign lymph nodes was (0.87 +/- 0.17) x 10(-3), (0.98 +/- 0.09) x 10(-3) and (1.20 +/- 0.10) x 10(-3) mm2/s. There was significant difference in ADC value between benign lymph nodes and other two groups (P < 0.01). The sensitivity, specificity and accuracy of WB-DWI in diagnosis of lymphoma were 100% (18/18), 30.8% (4/13) and 71.0% (22/31). When an ADC value of 1.08 x 10(-3) mm2/s was used as the threshold value for differentiating malignant from benign lymph nodes, the best results were obtained with sensitivity of 87.8% and specificity of 91.3%. Sixteen of eighteen cases (88.9%) of lymphoma were accurately staged in accordance with clinical staging.</p><p><b>CONCLUSIONS</b>WB-DWI is a sensitive, but less specific technique for diagnosis of lymphoma. It is difficult to differentiate lymphomatous from metastatic lymph nodes using WB-DWI. However, it is a valuable imaging modality for staging of patients with malignant lymphoma.</p>

Experimental study of inflammatory and metastatic lymph nodes with diffusion weighted imaging on animal model: comparison with conventional methods / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the feasibility of magnetic resonance (MR) diffusion weighted imaging (DWI) in discriminating inflammatory from VX2 carcinoma metastatic lymph nodes in rabbit model.</p><p><b>METHODS</b>Twenty New Zealand white rabbits were randomly divided into 2 groups. Complete Freund's adjuvant was injected into the bilateral dorsal footpads to set up ipsilateral lymphadenitis model (n = 10), and the other 10 rabbits received a subcutaneous implantation of VX2 tumor cell suspension (1.5 x 10(7) cells/mL) in both thighs to set up metastatic lymph node model. MR imaging scan covering the popliteal fossa and iliac fossa including short time inversion recovery echo-planar imaging DWI (STIR-EPI-DWI), T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI) was performed 2 weeks after injection. T2WI signal intensity (SI), DWI SI, long/short axial ratio (LSR) and apparent diffusion coefficient (ADC) values of the lymph nodes were evaluated in all cases. Right after MR imaging scan, popliteal and iliac fossa lymph nodes were collected for hematoxylin-eosin staining.</p><p><b>RESULTS</b>Totally 33 lymph nodes larger than 5 mm, including 22 inflammatory and 11 metastatic ones, were successfully isolated and taken into pathological analysis. LSR showed no significant difference between the inflammatory and malignant lymph nodes (P > 0.05). Both benign and malignant lymph nodes appeared iso-intense on T1WI and hyperintense on both T2WI and DWI images with an even lower T1WI and higher T2WI SI core at the hilum. Both T2WI and DWI SI showed no significant difference between two pathological groups (P > 0.01) in popliteal fossa. The mean ADC value of inflammatory nodes [(1.199 +/- 0.281) x 10(-3) mm2/s] was significantly higher than that of metastatic nodes [(0.858 +/- 0.090) x 10(-3) mm2/s, P < 0.01]. On ADC map, a high ADC value central area could be seen in most of the lymph nodes no matter benign or malignant. ADC value gave out the largest area under curve (AUC(ADC) = 0.955) compared with other three indexes (AUC(LSR) = 0.488; AUC(T2WI SI)= 0.727; AUC(DWI SI) = 0.822) and gave the best sensitivity and specificity in lymph node differential diagnosis compared with the other three indexes.</p><p><b>CONCLUSIONS</b>High quality DWI image can be obtained using STIR-EPI-DWI sequence in rabbit model. DWI is a new promising technique for differentiating inflammatory from metastatic lymph nodes. Compared with routine MR sequence, DWI could provide more useful physiological and functional information for diagnosis.</p>

Evaluation of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes with magnetic resonance imaging and proton magnetic resonance spectroscopy / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To study the characteristics of spectra on proton magnetic resonance spectroscopy (1H-MRS) and its value in patients with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS).</p><p><b>METHODS</b>Seven clinically diagnosed patients with MELAS underwent magnetic resonance imaging (MRI) and 1H-MRS examinations. The 1H-MRS techniques, characteristics of the spectra, and its correlation with the laboratory tests were analyzed.</p><p><b>RESULTS</b>Cerebral abnormalities were revealed in all 7 patients on conventional MR images, and most abnormal signals were observed in bilateral occipital, parietal, and temporal lobes. We found 4 cases with basal ganglia involvement, 2 cases with mild frontal lobe lesions, and 1 case with involvement of lateral cerebral peduncles and thalami. Additionally, 1 patient was involved with left insular lobe. Spectra from prominent lesions in brain parenchyma showed lactate doublet peak in 6 patients, 3 of whom were also noted lactate peak in ventricular cerebrospinal fluid (CSF).</p><p><b>CONCLUSION</b>1H-MRS may provide more direct information about the metabolism changes, which aids to affirm the diagnosis, and may replace the conventional invasive method of quantifying lactate in CSF.</p>

Assessment of myocardial viability with contrast-enhanced magnetic resonance imaging and comparison with single-photon emission computed tomography / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To compare contrast-enhanced magnetic resonance imaging (ceMRI) with nuclear metabolic imaging for the assessment of myocardial viability in patients with chronic ischemic heart disease.</p><p><b>METHODS</b>Twenty patients with suspected chronic ischemic heart disease underwent ceMRI and technetium-99m sestamibi single-photon emission computed tomography (SPECT). Patients with positive SPECT results also underwent 18F-fluorodeoxyglucose (FDG) SPECT. In a 17-segment model, the segmental extent of hyperenhancement (SEH) by ceMRI was compared with segmental FDG and sestamibi uptake by SPECT. Correlation between the extent of hyperenhancement by ceMRI and left ventricular function was analyzed.</p><p><b>RESULTS</b>Seven patients got negative results both in ceMRI and technetium-99m sestamibi SPECT. The rest 13 patients with positive results then underwent 18F-FDG SPECT. In 221 segments of 13 patients, SEH was (2.1 +/- 8.2)%, (25.0 +/- 13.7)%, and (57.7 +/- 23.6)% in segments with normal metabolism/perfusion, metabolism/perfusion mismatch, and matched defects, respectively, and there were significant differences between either two of them (all P < 0.05). By receiver operating characteristic curve analysis, the area under the curve was 0.95 for the differentiation between viable and non-viable segments. At the cutoff value of 34%, SEH optimally differentiated viable from non-viable segments defined by SPECT. Using this threshold, the sensitivity and specificity of ceMRI to detect non-viable myocardium as defined by SPECT were 92% and 93%, respectively. Hyperenhancement size by ceMRI was correlated negatively with the left ventricular ejection fraction (r = - 0.90, P < 0.01) and positively with left ventricular volumes (r = 0.62 for end-diastolic volume, r = 0.75 for end-systolic volume, both P < 0.05).</p><p><b>CONCLUSION</b>CeMRI allows assessment of myocardial viability with a high accuracy in patients with chronic ischemic heart disease.</p>

Retrospective analysis of magnetic resonance myocardial delayed enhancement / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To explore the imaging and related clinical characteristics of magnetic resonance (MR) delayed enhancement in patients with ischemic or nonischemic heart disease.</p><p><b>METHODS</b>Thirty-two cases who underwent MR myocardial cine and delayed enhancement imaging from January 2004 to October 2006 were retrospectively analyzed. The cine sequence imaging included the four-chamber view and the left ventricular short axis view. The delayed enhancement imaging was taken 10 minutes after the infusion of gadolinium from the antecubital vein with a segmented inversion-recovery-prepared T1-weighted fast gradient echo sequence. Patients underwent coronary computed tomography angiography (CTA) two weeks before or after the MR imaging examination. Combined with clinical history, the clinical and MR imaging characteristics of the patients who had delayed enhancement were analyzed.</p><p><b>RESULTS</b>MR delayed enhancement could be found in 16 cases. Among them, 12 cases had ischemic heart disease. Their coronary CTA showed one to three vessel diseases. The delayed enhancement was transmural or subendocardium, and the area of delayed enhancement corresponded well with one or more coronary arteries which had severe stenosis or occlusion. Four cases had nonischemic heart diseases. One case was dilated cardiomyopathy, with diffuse small midwall spots in delayed enhancemen and only 30% stenosis of the anterior descending coronary artery in coronary CTA. One case was hypertrophic cardiomyopathy, with delayed enhancement of strip- and patch-shaped at midwall of the hypertrophic myocardium. One case was restrictive cardiomyopathy, and the delayed enhancement was located in the area of subendocardium of both the right and left ventricles. Coronary CTA of these two cases were normal. The other case was a mass of the lateral wall of the left ventricle, and the delayed enhancement with a clumpy shape was located in the lateral wall of the left ventricle.</p><p><b>CONCLUSIONS</b>MR myocardial delayed enhancement is not a specific sign of myocardial infarction of ischemic heart disease. Nonischemic heart diseases including all kinds of primary cardiomyopathy and some other diseases affecting myocardium can also cause delayed enhancement, but their characteristics are different. The differentiation of the etiology of the nonischemic heart disease with delayed enhancement relies upon the intimate connection with clinical history and the cine sequence MR images.</p>