CLINICAL APPLICATION OF BODY DIFFUSION WEIGHTED MR IMAGING IN THE DIAGNOSIS AND PREOPERATIVE N STAGING OF CERVICAL CANCER

Objective To evaluate the clinical impact of body diffusion weighted imaging (DWI) on the diagnosis and preoperative N staging of cervical cancer. Methods 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. Results 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 adenocar- cinoma (n = 5) were (1.73 ± 0.31) ×10-3, (0.88 ± 0.22) ×10-3, and (1.08 ± 0.12) ×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) ×10-3 and (0.77 ± 0.13) ×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. Conclusions 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.

APPLICATION OF WHOLE BODY DIFFUSION WEIGHTED MR IMAGING FOR DIAGNOSIS AND STAGING OF MALIGNANT LYMPHOMA

Objective To evaluate the clinical impact of whole body diffusion weighted imaging (WB-DWI) on diagnosis and staging of malignant lymphoma. Methods 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. Results 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) × 10-3, (0.98 ± 0.09) × 10-3 and (1.20 ± 0.10) × 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 × 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. Conclusions 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.

Uterine Artery Embolization for Management of Primary Postpartum Hemorrhage Associated with Placenta Accreta

Objective To evaluate the efficacy and safety of uterine artery embolization(UAE) in the management of primary postpartum hemorrhage associated with placenta accreta. Methods We retrospectively reviewed the medical records of patients with placenta accreta between January 2010 and August 2014. Totally 18 women(mean age 30.8±4.2 years) of primary massive postpartum hemorrhage with diagnosis of placenta accrete received treatment of UAE after delivery. Images of DSA and medical records were reviewed. Technical success was defined as control of bleeding after embolization. The complications, control of hemorrhage and recurrent bleeding of the placenta left inside the uterus were retrospectively collected for assessment. Results All patients underwent transcatheter embolization of bilateral uterine arteries. The technical success rate of embolization was 100%. Bleeding was controlled in 17 of 18 patients(94%) during follow-up period(median 18 months, 3-31months) without further bleeding recurred. One patient with placenta percreta undertook an emergent hysterectomy along with surgical bladder repair after UAE because of persistent uterine bleeding. Eight patients had postembolization syndrome and no other complications occurred. Conclusion Uterine artery embolization is an effective and safe treatment for the management of primary postpartum massive hemorrhage associated with placenta accreta.

WHOLE BODY DIFFUSION WEIGHTED IMAGING:A NEW ERA OF ONCOLOGICAL RADIOLOGY

Cancer has become the leading cause of mortality in the urban area of China. Whole body diffusion weighted imaging (WB-DWI), also known as virtual positron emission tomography, has gradually become accepted as an image tool in tumor localization, characterization, staging and monitoring response to therapy or tumor recurrence. Our article aimed to summarize the limited initial clinical use of WB-DWI in the referred area, and to analyze the most potential advantage of WB-DWI in therapeutic monitoring and tumor staging. WB-DWI as a highly sensitive, completely non-invasive, well-tolerated and low price technique has a promising furture in tumor assessment. Profound clinical study is necessary for its further application improvement.

MR DIFFUSION WEIGHTED IMAGING FOR EVALUATION OF RADIOTHERAPEUTIC EFFECTS ON RABBIT VX2 TUMOR MODEL

Objective To investigate the feasibility of magnetic resonance (MR) diffusion weighted imaging (DWI) for evaluation of radiotherapeutic effects on rabbit VX2 tumor model. Methods Sixteen New Zealand white rabbits received a subcutaneous implantation of VX2 tumor cell suspension 0.5 mL (4×107 cells/mL) in their right thighs to set up tumor model. And 2 weeks later they were randomly divided into therapy group (Group T, n = 10) and control group (Group C, n = 6). Group T received radiotherapy at a single dose of 10 Gy. MR imaging (MRI) scan including short TI inversion recovery echo-planar imaging DWI, T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI) sequences were performed 1 day prior to as well as 1 day, 2 days, 3 days and 7 days after radiotherapy. Group C received only MRI scan at the same time points without any treatment. MRI appearance on T2WI, T1WI, and DWI images was compared and tumor volume was calculated. Apparent diffusion coefficient (ADC) values of the tumor were evaluated in all cases. HE staining was used for pathological study. Results Necrosis (n = 8) and hemorrhage (n = 2) were seen gradually on T2WI and T1WI images of Group T after time point of day 2 after irradiation. In Group C, no obvious necrosis was found until day 7. There was no significant difference in tumor volume between the two groups before radiotherapy. After radiotherapy, tumors in Group T showed a gradual growth but not as obvious as Group C. There was a significant difference in tumor volume between the two groups from day 2 on (P < 0.05). ADC value changed dramatically right from the 1st day after radio- therapy in Group T [(0.99 ± 0.15) ×10-3 mm2/s for 1 day before radiotherapy, (1.23 ± 0.08) ×10-3, (1.45 ± 0.07) ×10-3, (1.63 ± 0.06) ×10-3, and (2.02 ± 0.18) ×10-3 mm2/s for day 1, 2, 3, and 7]; and ADC value had no significant changes after radiotherapy in Group C except day 7 [(1.07 ± 0.08) ×10-3 mm2/s for 1 day before radiotherapy, (1.03 ± 0.04) × 10-3, (1.05 ± 0.02) ×10-3, (1.05 ± 0.05) ×10-3, and (0.95 ± 0.07) ×10-3 mm2/s for day 1, 2, 3, and 7]. There was significant difference in ADC value between the two groups for each time point after radiotherapy (P < 0.01). Pathological study showed that the number of viable tumor cells in Group T decreased 1 day after radiotherapy, and the inflammatory cell infiltration was marked and almost all viable tumor cells disappeared by day 7 after radiotherapy. Conclusions DWI is a new promising technique for monitoring radiotherapy outcomes. ADC value may give a prior clue on physiological changes of radiotherapy before routine MRI could tell.

Effects of Saline Administration, Abdominal Compression, and Prolongation of Acquisition Delay on Image Quality Improvement of CT Urography

Objective To retrospectively evaluate the effects of saline administration following contrast material injection, abdominal compression and two delay phase acquisition on image quality improvement of computed tomographic urography (CTU). Methods Medical records and informed consents of patients were obtained. In totally 122 patients (50 men, 72 women), two delay phase images with CTU were performed. Scans began simultaneously with a contrast bolus injection of 100 mL (300 mgI/mL) followed by a saline bolus injection of 100 mL at a rate of 5 mL/s. Two delay phase images were taken at 400 and 550 seconds for each patient. Examinations were taken by using abdominal compression or not. The distention and opacification of the urinary tract were evaluated by two interpreters together on transverse images and post-processing images. Effects of four techniques (saline administration and abdominal compression, saline administration only, compression only, and neither saline administration nor compression) and two delay phase acquisition on image quality improvement were analysed by using ANOVA and Chi-square test. Results Saline administration improved opacification (P<0.05) and increased overall image quality (P<0.01) of the intrarenal collecting system and proximal ureter. Abdominal compression (P<0.05) and delayed phase image acquisition of 550 seconds (P<0.01) all improved distention of the intrarenal collecting system and proximal ureter but did not improve opacification. No statistically significant effects on the distal ureter were found. However, there were more visualized distal ureteral segments with the longer imaging delay. Conclusion Saline administration, abdominal compression and longer imaging delays are all effective in improving image quality of 64-detector row CTU.

Placement of a Long Intestinal Tube in Patients with Early Postoperative Small Bowel Obstruction under Fluoroscopic Guidance

Objective To investigate the placement of a long tube into the small intestine under fluoroscopic guidance and to evaluate its decompression effect on early postoperative small bowel obstruction(EPSBO).Methods Fifty-four patients with EPSBO requiring decompression between April 2010 and July 2014 were enrolled in the study.Insertion of a long tube was guided by fluoroscopy.We first used the guide wire to pass the pylorus and then used the 10 Fr feeding tube as an exchangeable tube to put the superstiff wire into the duodenum.Finally the long tube could be passed over the guide wire through the pylorus into the intestine.The total procedure time,the radiation exposure time,and the incidence of complications were evaluated.Results The long tubes passed into the jejunum on initial insertion for all patients,so the success rate of this technique was 100%.The long tube was inserted into ileum in 18 patients.The mean total procedure time was 34.4±8.6 minutes,and the mean radiation exposure time 18.9±6.8 minutes.A total of 47 patients(87%) experienced full recovery following long-tube decompression and without the need for surgical intervention.Conclusions Using the wire-exchange technique,it is easy to place a long tube into the small bowel under fluoroscopic guidance.This decompression method is safe and effective for management of EPSBO.

EVALUATION OF MITOCHONDRIAL ENCEPHALOMYOPATHY WITH LACTIC ACIDOSIS AND STROKE-LIKE EPISODES WITH MAGNETIC RESONANCE IMAGING AND PROTON MAGNETIC RESONANCE SPECTROSCOPY

客观：在质子上学习系列的特征磁性的回声光谱学(1H 太太) 和它在有有乳的酸中毒和像击的事件(MELAS ) 的 mitochondrial encephalomyopathy 的病人的价值。方法：七临床上诊断的病人 withMELAS 经历了磁性的回声成像(MRI ) 和 1H 太太考试。1H 太太技术，系列的特征，和它与实验室测试的关联是 analyzed.RESULTS：服的畸形在传统的先生图象上在所有 7 个病人被揭示，并且很反常的信号被观察在双边枕骨，顶骨，和时间的脑叶。我们发现了 4cases 与基础与侧面的服的肉茎和 thalami 的参与轧了神经胶质参与，有温和正面的脑叶损害的 2 个盒子，和 1 个盒子。另外， 1 个病人涉及左海岛的脑叶。从在显示出的大脑实质的突出的损害的系列喂奶马甲山峰 in6 病人，其中 3 个也被注意喂奶在室的脑髓的液体(CSF ) 的山峰 .CONCLUSION：1H 太太可以关于新陈代谢变化提供更直接的信息，它帮助肯定诊断，并且可以代替确定的常规侵略方法喂奶 inCSF。

Assessment of Coronary Stents by 64-slice Computed Tomography: In-stent Lumen Visibility and Patency

Objective To assess lumen visibility of coronary stents by 64-slice computed tomography (CT) coronary angiography, and determine the value of 64-slice CT in non-invasive detecting of in-stent restenosis after coronary artery stent implantation. Methods Totally, 60 patients (54 males, aged 57.0±12.7 years) and 105 stents were investigated by 64-slice CT at a mean interval of 20.0±16.6 months after coronary stents implantation. Axial multi-planar reconstruction images of the stents and curved-planar reconstruction images through the median of the stents were reconstructed for evaluating stent image quality on a 5-point scale (1=excellent, 5=non assessable), and stent lumen diameter was detected. Conventional coronary angiography was performed in 18 patients, and 32 stents were evaluated. Results Image quality was good to excellent on average (score 1.71±0.76). Stent image quality score was correlated to heart rate (r=0.281, P<0.01) and stent diameter (r=-0.480, P<0.001). All the stents were assessable in lumen visibility with an average visible lumen diameter percentage of 60.7%±13.6%. Visible lumen diameter percentage was correlated to heart rate (r=-0.193, P<0.05), stent diameter (r=0.403, P<0.001), and stent image quality score (r=-0.500, P<0.001). Visible lumen diameter percentage also varied depending on the stent type. In comparison with the conventional coronary angiography, 4 of 6 in-stent stenoses were correctly detected. The sensitivity and specificity for the detection of in-stent stenosis were 66.7% and 84.6%, respectively. Conclusions Using a 64-slice CT, the stent lumen is partly visible in most of the stents. And 64-slice CT may be useful in the assessment of stent patency.

Non-enhanced Low-tube-voltage High-pitch Dual-source Computed Tomography with Sinogram Affirmed Iterative Reconstruction Algorithm of the Abdomen and Pelvis

Objective To investigate the image quality, radiation dose and diagnostic value of the low-tube-voltage high-pitch dual-source computed tomography(DSCT) with sinogram affirmed iterative reconstruction(SAFIRE) for non-enhanced abdominal and pelvic scans. Methods This institutional review board-approved prospective study included 64 patients who gave written informed consent for additional abdominal and pelvic scan with DSCT in the period from November to December 2012. The patients underwent standard non-enhanced CT scans(protocol 1) [tube voltage of 120 k Vp/pitch of 0.9/filtered back-projection(FBP) reconstruction] followed by high-pitch non-enhanced CT scans(protocol 2)(100 k Vp/3.0/SAFIRE). The total scan time, mean CT number, signal-to-noise ratio(SNR), image quality, lesion detectability and radiation dose were compared between the two protocols. Results The total scan time of protocol 2 was significantly shorter than that of protocol 1(1.4±0.1 seconds vs. 7.6±0.6 seconds, P<0.001). There was no significant difference between protocol 1 and protocol 2 in mean CT number of all organs(liver, 55.4±6.3 HU vs. 56.1±6.8 HU, P=0.214; pancreas, 43.6±5.9 HU vs. 43.7±5.8 HU, P=0.785; spleen, 47.9±3.9 HU vs. 49.4±4.3 HU, P=0.128; kidney, 32.2±2.3 HU vs. 33.1±2.3 HU, P=0.367; abdominal aorta, 44.8±5.6 HU vs. 45.0±5.5 HU, P=0.499; psoas muscle, 50.7±4.1 HU vs. 50.3±4.5 HU, P=0.279). SNR on images of protocol 2 was higher than that of protocol 1(liver, 5.0±1.2 vs. 4.5±1.1, P<0.001; pancreas, 4.0±1.0 vs. 3.6±0.8, P<0.001; spleen, 4.7±1.0 vs. 4.1±0.9, P<0.001; kidney, 3.1±0.6 vs. 2.8±0.6, P<0.001; abdominal aorta, 4.1±1.0 vs. 3.8±1.0, P<0.001; psoas muscle, 4.5±1.1 vs. 4.3±1.2, P=0.012). The overall image noise of protocol 2 was lower than that of protocol1(9.8±3.1 HU vs. 11.1±3.0 HU, P<0.001). Image quality of protocol 2 was good but lower than that of protocol 1(4.1±0.7 vs. 4.6±0.5, P<0.001). Protocol 2 perceived 229 of 234 lesions(97.9%) that were detected in protocol 1 in the abdomen and pelvis. Radiation dose of protocol 2 was lower than that of protocol 1(4.4±0.4 m Sv vs. 7.3±2.4 m Sv, P<0.001) and the mean dose reduction was 41.4%. Conclusion The high-pitch DSCT with SAFIRE can shorten scan time and reduce radiation dose while preserving image quality in non-enhanced abdominal and pelvic scans.

Evaluation of Normal Adrenal Gland Volume by 64-slice CT

Objective To measure volume and other parameters of normal adrenal glands in Chinese adults with 64-slice multidetector CT, to evaluate the relationship of volume result with age, sex and body size, and to explore the correlations between adrenal volume and other measurements. Methods This study was based on 125 acquired contrast-enhanced upper abdominal CT scans performed with a 64-slice CT. The final study group consisted of 81 patients (49 males, 32 females). Portal venous phase images were studied for the measurements. Both the reconstruction interval and thickness were 1.5 mm. Each adrenal gland was outlined manually with computer-assistant technology to calculate its volume. The maximal sectional area, length, width and thickness of each adrenal gland were also measured. Results The mean age of total population was 47.9±13.0 (range: 20-76) years. The left, right, and total adrenal gland volumes were 4.23±0.74 (range: 2.85-5.83) cm 3 , 4.26±0.86 (2.59-6.56) cm 3 , and 8.50±1.40 (5.80-11.39) cm 3 , respectively. These volumes increased with weight (r=0.381, 0.389, and 0.437 respectively, all P<0.001), height (r=0.386, P<0.001; r=0.297, P=0.007; r=0.384, P<0.001) and body surface area (r=0.406, 0.392, and 0.452, all P<0.001). There was no significant difference in left, right or total adrenal volume with regard to sex after applying General Linear Model procedure to reduce the impact of weight (F=1.304, 0.064, and 0.597, all P>0.05), nor did volume change significantly with age (r=-0.033, -0.014, and -0.026, all P>0.05). Nearly all descriptors of bilateral adrenal glands correlated with ipsilateral volume except thickness (r=-0.027, P=0.814) and width (r=0.166, P=0.138) in the left side. Among these parameters, length had a stronger correlation with volume than others in the both left (r=0.412, P<0.001) and right (r=0.516, P<0.001) adrenal glands. Conclusion Our study has defined the volume distribution and other parameters of normal adrenal glands in Chinese adults, which provide a baseline for future studies.

CORONARY ANGIOGRAPHY WITH DUAL SOURCE COMPUTED TOMOGRAPHY:INITIAL EXPERIENCE

Objective To explore the scan technique and image quality of coronary angiography with dual source computed tomography(CT) without oral metoprolol preparation.Methods Plain and enhanced dual source CT coronary angiography without oral metoprolol preparation was prospectively performed in 600 patients.Calcium scoring with plain scan images as well as multi-planar reconstruction(MPR),maximum intensity projection(MIP),and volume rendering technique(VRT) reconstruction with enhanced scan images were performed in all cases.The scan technique and post-reconstruction experience was summarized.The image quality was classified as 1 to 4 points,and coronary segments classified according to the American Heart Association standards were evaluated.Results The average calcium score of the 600 cases was 213.6±298.7(0-3 216.5).The average heart rate of the enhanced scan was 82.1±16.2(47-139) bpm.The post-reconstruction methods with which coronary segments could be shown as best as possible consisted of single phase reconstruction method,two or more phases supplemented method,and electrocardiogram editing method.Altogether 8 457 coronary segments were evaluated,among which 97.2% were evaluated as point 1,1.7% point 2,0.5% point 3,and 0.6% point 4.The coronary segments in 261 cases were completely normal,while 360 segments were diagnosed with <50% stenosis and 625 segments with ≥50% stenosis.Conclusions Excellent coronary artery image can be obtained with dual source CT in patients with any heart rate without oral metoprolol preparation.Heart rate is not a major source of the artifact,coronary segments can be well shown with single or multiple-phase reconstruction method.

METABOLIC ABNORMALITIES IN MESIAL TEMPORAL LOBE EPILEPSY PATIENTS DEPICTED BY PROTON MR SPECTROSCOPY USING A 3.0T MR SCANNER

Objective To evaluate metabolic abnormalities in patients with mesial temporal lobe epilepsy (MTLE) with proton magnetic resonance spectroscopy (MRS) using a 3.0T MR scanner. Methods Sixty-three patients (32 women and 31 men) with diagnosed MTLE underwent diagnostic MR imaging (MRI) and proton MRS using a 3.0T MR scanner. The clinical history and interictal epileptiform discharges (IEDs) were recorded. Sixteen healthy volunteers served as control. The results of proton MRS were compared with the findings of electroencephalogram and structural MRI findings. Results Twenty-seven of the 63 patients with MTLE showed unilateral hippocampal sclerosis, and 9 showed bilateral hippocampal sclerosis. The concentration ratio of N-acytelaspartate (NAA)/ in the hippocampal region of MTLE patients (0.64±0.07) was significantly lower than control (0.80±0.05, P= 0.023). In the patients with unilateral hippocampal sclerosis, NAA/(Cr+Cho) in the hippocampal region ipsilateral to the sclerotic hippocampus (0.56±0.06) was significantly lower than the ratio in the contralateral hippocampal region (0.69±0.07, P<0.001). There was significant difference in hippocampal NAA/(Cr+Cho) between the refractory patients and the non-refractory patients (0.64±0.05 vs. 0.71±0.07, P=0.04). Forty-five patients were lateralized by IEDs, while 49 patients were lateralized by metabolite ratio. And lateralization determined by proton MRS and IEDs was concordant in 33 patients. Conclusions MRS as a noninvasive tool adds helpful metabolite information to routine MRI in evaluation of MTLE. The method is well established and should be a routine clinical application in the investigation of epilepsy.

EXPERIMENTAL STUDY OF INFLAMMATORY AND METASTATIC LYMPH NODES WITH DIFFUSION WEIGHTED IMAGING ON ANIMAL MODEL: COMPARISON WITH CONVENTIONAL METHODS

Objective To investigate the feasibility of magnetic resonance (MR) diffusion weighted imaging (DWI) in discriminating inflammatory from VX2 carcinoma metastatic lymph nodes in rabbit model. Methods 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 (1.5×107 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. Results 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 popli- teal fossa. The mean ADC value of inflammatory nodes [(1.199 ± 0.281) ×10-3 mm2/s] was significantly higher than that of metastatic nodes [(0.858 ± 0.090) ×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 (AUCADC = 0.955) compared with other three indexes (AUCLSR = 0.488; AUCT2WI SI = 0.727; AUCDWI SI = 0.822) and gave the best sensitivity and specificity in lymph node differential diagnosis compared with the other three indexes. Conclusions 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.

Clinical Value of Dual-energy CT in Detection of Pancreatic Adenocarcinoma: Investigation of the Best Pancreatic Tumor Contrast to Noise Ratio

Objective To quantitatively compare and determine the best pancreatic tumor contrast to noise ratio (CNR) in different dual-energy derived datasets. Methods In this retrospective, single center study, 16 patients (9 male, 7 female, average age 59.4±13.2 years) with pathologically diagnosed pancreatic cancer were enrolled. All patients received an abdominal scan using a dual source CT scanner 7 to 31 days before biopsy or surgery. After injection of iodine contrast agent, arterial and pancreatic parenchyma phase were scanned consequently, using a dual-energy scan mode (100 kVp/230 mAs and Sn 140 kVp/178 mAs) in the pancreatic parenchyma phase. A series of derived dual-energy datasets were evaluated including non-liner blending (non-linear blending width 0-500 HU; blending center -500 to 500 HU), mono-energetic (40-190 keV), 100 kVp and 140 kVp. On each datasets, mean CT values of the pancreatic parenchyma and tumor, as well as standard deviation CT values of subcutaneous fat and psoas muscle were measured. Regions of interest of cutaneous fat and major psoas muscle of 100 kVp and 140 kVp images were calculated. Best CNR of subcutaneous fat (CNR F ) and CNR of the major psoas muscle (CNR M ) of non-liner blending and mono-energetic datasets were calculated with the optimal mono-energetic keV setting and the optimal blending center/width setting for the best CNR. One Way ANOVA test was used for comparison of best CNR between different dual-energy derived datasets. Results The best CNR F (4.48±1.29) was obtained from the non-liner blending datasets at blending center -16.6±103.9 HU and blending width 12.3±10.6 HU. The best CNR F (3.28±0.97) was obtained from the mono-energetic datasets at 73.3±4.3 keV. CNR F in the 100 kVp and 140 kVp were 3.02±0.91 and 1.56±0.56 respectively. Using fat as the noise background, all of these images series showed significant differences (P<0.01) except best CNR F of mono-energetic image sets vs. CNR F of 100 kVp image (P=0.460). Similar results were found using muscle as the noise background (mono-energetic image vs. 100 kVp image: P=0.246; mono-energetic image vs. non-liner blending image: P=0.044; others: P<0.01). Conclusion Compared with mono-energetic datasets and low kVp datasets, non-linear blending image at automatically chosen blending width/window provides better tumor to the pancreas CNR, which might be beneficial for better detection of pancreatic tumors.

SPECTRUM OF FUNCTIONING ISLET CELL TUMOR ON MULTISLICE COMPUTED TOMOGRAPHY:EXPERIENCE ON 70 PATIENTS

Objective To review experience in preoperative detection of islet cell tumors using multislice computed tomography (MSCT) and summarize various imaging features of functioning islet cell tumors on enhanced MSCT.Methods Seventy patients with clinical or pathological diagnosis of functioning pancreatic islet cell tumor between October 2003 and February 2007 were included in this retrospective study. Seventy-four enhanced MSCT scans in these patients were identified. All MSCT scans were interpreted by two experienced radiologists by consensus interpretation. Surgery and pathology reports were used to confirm the diagnosis, localization, and size of tumors.Results Totally, 73 functioning islet cell tumors including 65 benign insulinomas, 2 benign glucagonomas, 3 malignant insulinomas, and 3 malignant glucagonomas were pathologically diagnosed. Tumors in only two cases were not found by MSCT. In 67 benign lesions, 32 showed typical enhancement style, 21 showed prolonged enhancement in portal venous phase, 4 showed delayed enhancement, 4 had iso-dense enhancement with normal pancreatic parenchyma, 2 had no enhancement at all in arterial phase and portal venous phase, and 4 had inhomogeneous enhancement with necrosis or cyst-formation. Patchy or spotty calcifications were found in 3 of the 67 tumors. In 6 malignant islet cell tumors, vessel invasion (2/6) and bowel invasion (1/6) were seen. Different enhancement patterns were shown. All hepatic metastases showed hyper-enhancement during their arterial phase. ConclusionsPancreatic islet cell tumor may display a wide spectrum of presentations in MSCT. Tumors with unusual appearances often present as diagnostic challenges. Non-contrast and post-contrast multiphase scans are recommended for the localization of functioning islet cell tumors.

Carney complex: Two case reports and review of literature

Carney complex(CNC) is an extremely rare genetic syndrome of pigmented skin lesions, endocrine hyperfunction and myxoma. Given its diverse clinical manifestations, CNC is often misdiagnosed. Recognition of some special clinical manifestations and imaging features may help with the diagnosis. Early diagnosis of CNC would alert ongoing surveillance of tumors and complications; the prognosis of CNC may thus be improved by early treatment. Herein, we report two cases of CNC with bone lesions.

Determinants of Detection of Stones and Calcifications in the Hepatobiliary System on Virtual Nonenhanced Dual-energy CT

Objective To retrospectively determine the features of stones and calcifications in hepatobiliary system on virtual nonenhanced(VNE) dual-energy computed tomography(CT), and to evaluate the possibility of VNE images in diagnosis for those lesions. Methods A total of 128 gall stones and calcifications of the liver found in 110 patients were examined with triple phase abdominal CT scan from July 2007 to December 2011, in which true nonenhanced(TNE) phase and arterial phase were performed with single-energy CT(120 kVp) and portal venous phase was performed with dual-energy CT(100 kVp and 140 kVp). VNE images were generated from the portal venous phase dual-energy CT data sets by using commercially VNC software. The mean CT values for the stone, liver, bile and paraspinal muscle, mean lesion density and size in area dimension, contrast-to-noise ratio(CNR) of lesion to the liver or bile, and image noise were assessed and compared between VNE and TNE images. The effective dose and size-specific dose estimate(SSDE) were also calculated. Results The mean CT values of the lesions measured on VNE images declined significantly compared with those measured on TNE images(164.51±102.13 vs. 290.72±197.80 HU, P<0.001), so did the lesion-to-liver CNR(10.80±11.82 vs.18.81±17.06, P<0.001) and the lesion-to-bile CNR(17.24±14.41 vs. 21.32±17.31, P<0.001). There was no significant difference in size of lesions area between VNE and TNE images(0.69±0.88 vs. 0.72±0.85 cm2, P=0.062). Compared to the 128 lesions found in TNE images, VNE images showed the same density in 30(23.4%) lesions, lighter density in 88(68.8%) lesions, while failed to show 10(7.8%) lesions, and showed the same size in 61(47.7%) lesions and smaller size in 57(44.5%)lesions. The CT cutoff values of lesion and size were 229.21 HU and 0.15 cm2, respectively. The total effective dose for triple phase scan protocol with TNE images was 19.51±7.03 mS v, and the SSDE was 39.84±11.10 mGy. The effective dose for dual phase scan protocol with VNE images instead of TNE images was 13.29±4.89 m Sv, and the SSDE was 27.83±9.99 mGy. Compared with TNE images, the effective dose and SSDE of VNE images were down by 32.05%±3.69 % and 30.63%±2.34 %, respectively. Conclusions Although the CT values and CNR of the lesions decreased in VNE images, the lesions of which attenuation greater than 229.21 HU and size larger than 0.15 cm^2 could be detected with good reliability and obvious dose reduction. There was good consistency in the size of stones and calcifications in hepatobiliary system between VNE images and TNE images, which ensured the possibility of the clinical application of VNE images.

Life-threatening Spontaneous Retroperitoneal Haemorrhage:Role of Multidetector CT-angiography for the Emergency Management

Objective To evaluate the role of multidetector computed tomography-angiography(MDCTA) for management of life-threatening spontaneous retroperitoneal haemorrhage(SRH).Methods A retrospective analysis of the medical records of all SRH patients admitted to our hospital from January 1,2005 to November 31,2014 was performed.SRH was defined as unrelated to invasive procedures,surgery,trauma,abdominal tumor or aortic aneurysm.Life-threatening SRH was defined as hemodynamic instability with hypotension.Sixteen cases met the inclusive criteria.Patients' characteristics,clinical presentation,imaging of MDCTA,treatment modalities,morbidity,and follow-up data were analyzed.Results The group of 16 patients included 11 men and 5 women,with a mean age of 51.5 ± 16.4years.All patients underwent MDCTA scan examinations,and active contrast media(CM) extravasation were found in 9 patients.Angiography was performed for 8 patients in the CM extravasation group.Bleeding vessels were found in 7 patients who underwent successful embolization.One patient in the CM extravasation group did not undergo angiography and died of bleeding.Seven patients without active CM extravasation underwent conservative management.Bleeding was controlled for all these 7 patients,and 1 patient died of multiple organ failure.Fourteen patients survived from SRH were successfully discharged.One patient died of heart failure during follow-up.Conclusion MDCTA was useful in the diagnosis of SRH and proved to be predictive for the outcome of conservative treatment and early intervention.

Normative Measurements of Extraocular Musculature by Multislice Computed Tomography

Objective To establish the normal measurements of diameter of extraocular muscles (EOMs) by multislice computed tomography (CT). Methods Orbits of 50 volunteers (25 male and 25 female) were scanned with a multislice CT scanner. For each subject, one axial image at the central level of the eyeball, one coronal image about 1 cm behind globe, and two oblique sagittal images respectively along the left and right optic nerve were used for measurements of the thickness and width of EOMs. The statistic significance of measurement value between male and female and between left and right eyes was evaluated. Results There were no significant differences in the thickness and width of superior muscle group, lateral rectus, medial rectus, lateral rectus, superior oblique, inferior oblique and the thickness of levator palpebrae superioris between the left and right eyes as well as between male and female groups (all P>0.05). The thickness of superior muscle group and inferior rectus had not significant difference (2.9±0.7 vs. 3.3±0.8 mm, P=0.162), while the thickness of medial rectus was significantly higher than that of lateral rectus (3.1±0.5 vs. 2.2±0.6 mm, P=0.000). Conclusions The CT measurement of extraocular musculature is simple and time-saving and can be applied in the clinical work. The normative data obtained may be useful in determining pathologic enlargement of the EOMs in both thyroid-associated orbitopathy patients and other various orbital conditions.