فهرست مطالب

Iranian Journal of Radiology - Volume:16 Issue:2, 2019
  • Volume:16 Issue:2, 2019
  • تاریخ انتشار: 1398/01/11
  • تعداد عناوین: 20
|
  • Farzad Vaghef Davari *, Reza Abaee , Mahnaz Hodaei , Mir Saeed Yekaninejad , Shahrokh Ghazizade , Aazam Khorassani Page 1
    Background
    Pilonidal disease is one of the most prevalent surgical problems among young patients. Despite easy diagnosis of most cases by physical examination, there remain some patients with suspicious diagnoses.
    Objectives
    There is an obvious lack of standardized imaging tools for diagnosis of pilonidal disease, therefore, we investigated the diagnostic value of ultrasonography.
    Patients and Methods
    This diagnostic study was performed on a group of patients with confirmed pilonidal sinus and a control group without any sign of the disease. The number of subcutaneous tracts, size of cavities, and presence of hair were detected by superficial probe ultrasonography.
    Results
    The sensitivity and specificity of ultrasonography in detecting pilonidal disease was 96% and 100%, respectively. Ultrasonography detected sinus tracts in 72%, cavities in 96% and hair in 68% of involved patients.
    Conclusion
    Based on the excellent diagnostic performance of ultrasonography for pilonidal disease, we recommend this imaging tool in patients with suspicious diagnosis and unconfirmed recurrence of pilonidal disease.
    Keywords: Pilonidal Sinus, Ultrasonoghraphy, Diagnosis
  • Wonju Hong , Sun, Young Park *, Soo Kee Min , Je, Hyun Yoo , Sung Hye Koh , Kwanseop Lee Page 2
    Localized tenosynovial giant cell tumor (L-TGCT), formerly called giant cell tumor of the tendon sheath, is one of the benign proliferative diseases of the synovium of a joint, bursa, or tendon sheath. L-TGCT occasionally involves a large joint such as the knee, and rarely it is combined with infarction by pedicle torsion. Neither the prevalence of torsion of L-TGCT nor the mechanism involved are known, but it is thought to be uncommon progress. Herein, we describe a rare case of infarcted L-TGCT in the knee involving torsion of a mass pedicle in a 47-year-old man. We utilized magnetic resonance imaging including diffusion-weighted imaging and axial apparent diffusion mapping, and sonographic appearance during the course of investigations, because radiologic findings showed characteristic features of infarcted L-TGCT.
    Keywords: Infarction, Knee Joint, Magnetic Resonance Imaging, Tenosynovial Giant Cell Tumor, Ultrasound
  • Soo, Hyun Kim , Ha Yeun Oh *, Young, Joon Ryu Page 3
    Phyllodes tumor is a fibroepithelial lesion that accounts for 0.3 % to 1.0 % of all breast neoplasms, and it is commonly observed as a fast-growing breast mass. Recurrences are frequent regardless of the histology, both in benign and malignant phyllodes tumors, and when it recurs, the prognosis is known as very poor. The average time to local recurrence reported is around two years from the initial excision. In this report, we describe a case of a benign phyllodes tumor of the breast recurring as a rapidly growing recurrent malignant phyllodes tumor in a 45-year-old woman, along with the imaging findings. There are many reports about recurrent phyllodes tumor in the medical field. However, the fascinating point about this case is the very short time interval of recurrences (shortest within one week) at the same location. To our knowledge, no case has been reported with such short interval time.
    Keywords: Breast, Phyllodes Tumor, Recurrence
  • Wen, Fei Li *, Tahir Mehmood Shakir , Yuemei Zhao , Tao Chen , Chen Niu , Zhanqiu Wang Page 4
    Background
    A precise preoperative diagnosis is important for the treatment of patients, and the extent of rotator cuff tears will determine the patient’s choice of conservative treatment or surgical treatment.
    Objectives
    This paper was conducted to assess the diagnostic accuracy of magnetic resonance imaging (MRI) in the evaluation of rotator cuff tears.
    Materials and Methods
    A computerized search using PubMed, EMBASE, Chinese Biomedical databases, Web of Knowledge, and Cochrane Libraries was performed to identify original research studies by two independent reviewers separately.
    Results
    Eighteen surveys that investigated MRI to diagnose rotator cuff tears were included. Influence factors on the diagnostic accuracy were evaluated using meta-regression analysis. For any rotator cuff tear, the pooled sensitivity and specificity were 0.93 and 0.88, respectively. Overall, MRI had higher pooled sensitivity (0.87) and specificity (0.93) of full-thickness tears, relative to sensitivity (0.80) and specificity (0.92) of partial tears. In addition, the overall area under the curve (AUC) of MRI for identifying full-thickness tears (96%) was close to that for any rotator cuff tear, a value that was much higher than for partial tears (86%). Threshold effects were not significant in this meta-analysis.
    Conclusion
    After analyzing the results of this study, we demonstrated that MRI had excellent performance regarding the diagnosis of rotator cuff tears. Our study showed that the diagnostic accuracy of MRI in diagnosing full-thickness rotator cuff tear is significantly better than that of partial thickness rotator cuff tears.
    Keywords: MRI, Rotator Cuff Tear, Meta-Analysis
  • Xin, Ping Kuai , Sheng, Yu Wang , Chuan, Hai Jia *, Jia, Ming Qiu Page 5
    Synovial sarcomas (SS) are soft tissue neoplasms that usually occur in the vicinity of large joints. Herein, we present the case of a 48-year-old man with renal synovial sarcoma (RSS). The clinical manifestations, computed tomography (CT) scan and magnetic resonance imaging (MRI) features, microscopic characteristics, and immunohistochemical findings of this uncommon tumor are described.
    Keywords: Synovial Sarcoma, Kidney, Computed Tomography, Magnetic Resonance Imaging
  • Yook Kim , Jisun Lee *, Kyung Sik Yi , Soo Hyun Lee , Bum Sang Cho , , Kil Sun Park Page 6
    Postpancreatectomy hemorrhage (PPH) is a rare but serious complication that can lead to death. Although the best treatment option for PPH remains controversial, transcatheter arterial embolization (TAE) has recently been introduced as a treatment with safety and efficacy, showing low morbidity and mortality, especially in late PPH (> 24 h after surgery). The most common location for PPH is the gastroduodenal artery stump; however, hemorrhage may occur from unusual sources, such as the dorsal pancreatic artery (DPA), which is often difficult to detect on angiography. Herein, the authors report three cases of delayed PPH from the DPA, occurring after a Frey procedure in one case and after pylorus-preserving pancreaticoduodenectomy in the other two. All patients were successfully treated using TAE. Although the involved artery was not identified on the first angiography in two patients, rebleeding was successfully managed by repeated endovascular procedures. Therefore, a careful and repetitive approach, based on awareness of the various causes of PPH, could increase the success rate of TAE.
    Keywords: Pancreatectomy, Hemorrhage, Embolization, Therapeutic, Arteries, Anatomic Variation, Dorsal Pancreatic Artery (DPA)
  • Yu Hui Won, Eun Hae Park * Page 7
    The current case report presents a 17-year-old man newly diagnosed with Hirayama Disease (HD) with right-side upper limb weakness, which was best detected by full cervical flexion scan in the prone position, using a serial trial of flexion Magnetic Resonance Imaging (MRI). Using a neck coil resulted in inadequate flexion angle because of limited space and failed to demonstrate anterior dural displacement, which is known to be the most significant and important finding for the diagnosis of HD. By serial flexion scan, the researchers found that dural displacement may not be evident because of an insufficient flexion angle, and that as the flexion angle increases, the diameter and level of anterior dural displacement increases, emphasizing the necessity of full-flexion imaging in patients with clinically suspicious HD. In the present case, the prone position provided comfortable stabilization for ideal full-flexion position, resulting in optimized image quality.
    Keywords: Hirayama Disease, Cervical MRI, Prone Position
  • Deok, Soo Kim , Sung, Dong Kim , Hak, Jin Kim , Kyu, Sup Cho * Page 8
    Carcinoid tumors are neuroendocrine tumors that usually occur in the digestive tract and lung. They are rarely found in the head and neck, especially in the sinonasal area. This article describes a typical carcinoid tumor involving the sphenoid sinus, cavernous sinus, sphenoid bone, clivus, and occipital condyle, which was treated successfully by endoscopic transseptal transsphenoidal surgery and intensity-modulated radiation therapy.
    Keywords: Carcinoid Tumor, Neuroendocrine Tumors, Sphenoid Sinus, Radiotherapy, Intensity-Modulated
  • Xiaoyuan Liu , Jianqiang Ye , Yan Zhang , Quan Liu , Ruizhen Bai , Wenbo Yuan , Dongyan Cai , Xiaoyuan Zheng , Yun Bian , Shijun Zhou , Juan Lv , Yongjuan Ding , Fen Xie , Hongwen Lu , Bingxue Xie * Page 9
    Background
    Despite studies on positron emission tomography/magnetic resonance imaging (PET/MRI) in oncological imaging with high soft-tissue contrast resolution, PET/MRI has not been studied in ophthalmology. 89Zr-bevacizumab, designed as a probe for PET, targets vascular endothelial growth factor, which is highly expressed in ocular angiogenesis. Intravitreal injections of bevacizumab agents have curative effects on ocular disease.
    Objectives
    To study the ocular biodistribution of 89Zr-bevacizumab in New Zealand rabbits using PET/MRI.
    Materials and Methods
    89Zr-bevacizumab, synthesized from conjugated bevacizumab and 89Zr-oxalate, and the purity of radiolabeled antibodies were determined using radio high-performance liquid chromatography (radio-HPLC). Instant thin-layer chromatography (ITLC) was utilized to differentiate the labeled product from aggregates and unlabeled 89Zr. 89Zr-bevacizumab was injected 2 mm from the left limbus into the vitreous humor of six normal New Zealand white rabbits. Micro-PET was utilized for dynamic imaging from 5 minutes to 60 minutes postinjection and for static imaging at 4 hours, 24 hours, 48 hours, 120 hours, and 144 hours (10-minutes scans) postinjection. PET/MRI scans were fused using PMOD software.
    Results
    89Zr-bevacizumab with a radiochemical purity of 93.21% was monitored via PET imaging. Radioactivity levels in the eyes plateaued approximately 5 minutes after administration of 89Zr-bevacizumab, and the measured vitreous values decreased from 340.52 ± 41.6% injected dose (ID)/g to 21.53 ± 3.39%ID/g by 144 hours. The half-life of the drug in the eye was calculated for 84.25 hours.
    Conclusion
    89Zr-bevacizumab could be monitored in animals by PET imaging, and the radiolabel exhibited high sensitivity in the vitreous body. Radioactivity levels in the eyes plateaued approximately 5 minutes after administration. This study clearly demonstrates the biodistribution of 89Zr-bevacizumab.
    Keywords: 89Zr-Bevacizumab, PET-MRI, Eye, Distribution
  • Xin Xu, Xuening Zhang *, Honggen Liu Page 10
    Background
    Percutaneous catheter drainage (PCD) therapy is an important treatment for severe acute pancreatitis.
    Objectives
    The purpose of this retrospective study was to analyze the relevant risk factors of computed tomography (CT) guided PCD during the treatment of infected pancreatic necrosis (IPN) in severe acute pancreatitis.
    Patients and Methods
    This is a retrospective study. From January 2013 to November 2016, 162 patients suffering from severe acute pancreatitis with IPN were assessed using CT-guided PCD. Abdominal CT scan was performed for the patients. The interventional therapist chose the location and puncture according to the image. Depending on the efficacy and process of the treatment, these patients were divided into a PCD success treatment group and a PCD combined with surgery group. Factors affecting the success of PCD treatment were analyzed by logistic regression analysis.
    Results
    Among the 162 cases, 71 cases (43.82%) were in the PCD success group and 91 cases (56.17%) were in the PCD combined with surgery group. Through the course of treatment, CT values of piercing zone, acute physiology and chronic health evaluation II (APACHEII) scores and modified CT severity index (MCTSI) scores showed statistically significant correlation with the therapeutic effect of PCD under CT guidance. A further multivariate analysis found that the CT value of puncture area is the best predictor for efficacy and when the CT value got higher the PCD efficacy would become lower. We performed further analysis of the factors associated with the average CT value in the puncture area which was higher than 20 Hounsfield unit (HU), and found that the length of time from patient admission to drainage, APACHEII scores, MCTSI scores and C reactive protein (CRP) levels were risk factors for PCD treatment efficacy.
    Conclusion
    CT values of piercing zone is the major risk factor affecting the curative effect of CT guidance PCD. For patients with higher CT values in the puncture area, the longer time from patient admission to drainage, the higher APACHEII scores and MCTSI scores. Higher levels of C reactive protein seem to lower the curative effect.
    Keywords: Severe Acute Pancreatitis, CT Guided, Percutaneous Catheter Drainage
  • Zeynep Keskin , Mihrican Ye?ilda? , Ender Alkan , Ay?egül Kayhan , ?smet Tolu , Suat Keskin * Page 11
    Background
    Pleural effusion could develop in very different pathological conditions. It is important to characterize pleural effusion and to identify its etiology. Different radiological methods, such as ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI) are used for the diagnosis of pleural effusion.
    Objectives
    To assess the ability of diffusion weighted imaging and apparent diffusion coefficient (ADC) maps to differentiate transudative effusions (TEs) from exudative effusions (EEs).
    Patients and Methods
    This prospective observational, single center study was performed on 100 consecutive patients who had pleural fluid detected by chest X-ray, US, or CT and were referred for MRI. Afterwards diffusion-weighted MRI (DW-MRI) was obtained using a multislice, single shot, respiratory triggered spin echo, echo planar imaging sequence. Pleural effusions obtained with thoracentesis were classified into TEs or EEs according to the clinical criteria established by clinical, pathologic findings and Light's criteria. Analysis of MRI was interpreted by one radiologist specialist who was blinded to clinical findings and according to the clinical criteria established by Light.
    Results
    The ADCs of EEs were significantly lower than those of the TEs. The difference between the mean ADC values of TEs and EEs was significant (P < 0.01). The optimum cutoff point for ADC values was 3.51 × 10-3 mm2/s, with a sensitivity of 90.4% and a specificity of 78%.
    Conclusion
    We conclude that ADC value is a noninvasive, reliable, and reproducible imaging parameter that may help to assess and characterize pleural effusion.
    Keywords: Pleural Effusion, Diffusion Weighted Imaging, Apparent Diffusion Coefficient
  • Mehdi Samavati, Alireza Ahmadian *, Hamidreza Abtahi, Amirhossein Golnabi, Reza Arjmandi Asl Page 12
    Background
    Bronchoscopy is a difficult procedure for physicians to relate CT slices to bronchoscopic video images and maneuver the bronchoscope inside the airway tree. CT-guided bronchoscopy systems have been developed in the last decades to help physicians maneuver the bronchoscope inside the airway tree in a fast and precise way.

    Objectives
    We aimed to develop a continuous guiding method for bronchoscopy with high tracking accuracy by matching bronchoscopy image contours with CT contours, and speed it up by using synchronous electromagnetic tracker (EMT) data, and to evaluate it on airway phantom with simulated respiratory motion.

    Materials and Methods
    This method works based on two approaches combined together: 1) Contours detected in real bronchoscopy images and finding their equivalents in CT space. Contours are detected by a fast algorithm and CT contours are mapped by them in a perspective scheme. 2) EMT data which is used in a frame by frame approach to approximate the position of bronchoscope compared to its previous position. This differential approach causes a small search space and as a result higher tracking speed. The novelty of this work is using bronchoscopy image contours instead of the whole image combined with synchronous EMT data. This approach causes faster tracking and there is no need for landmark selection or centerline consideration before performing the main bronchoscopy.

    Results
    The experimental results of implementing the proposed method show that this method can track the bronchoscope continuously. For evaluating the accuracy and robustness of tracking, virtual bronchoscopy images were generated at each frame position reported by the method and compared to corresponding real bronchoscopy image using mutual information. The experimental results present that this method can track a bronchoscope accurately and robustly in 96.3% of frames.

    Conclusion
    Using contours instead of the whole image for registration can provide a continuous real-time bronchoscopy tracking procedure. Using EMT data in differential mode makes the proposed method robust to simulated respiratory motion.
    Keywords: CT-Guided Bronchoscopy, Bronchoscopy Navigation, Contour-Based 2D, 3D Image Registration, Hybrid Tracking
  • Sung Mo Kim, Sang Soo Shin *, Byung Chan Lee, Jin Woong Kim, Suk Hee Heo, Chung Hwan Jun, Yong Yeon Jeong Page 13
    Background
    In the case of combined therapy, potential accumulation of iodized oil (lipiodol) in the liver parenchyma around the index tumor may directly interfere with the imaging evaluation of the treatment efficacy immediately after the procedure. We postulated that magnetic resonance imaging (MRI) has the potential to precisely evaluate the ablation zone immediately after radiofrequency ablation (RFA) combined with conventional transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) because the effect of lipiodol retention on MRI signal intensity is minimal.

    Objectives
    To prospectively compare multidetector-row CT (MDCT) and MRI for evaluation of the ablative margin (AM) and index tumor immediately after combined treatment with conventional TACE and ultrasound-guided RFA for HCC.

    Patients and Methods
    This study included 33 consecutive patients with 45 HCCs in whom both contrast-enhanced MDCT and MRI were performed immediately after RFA combined with TACE. Two radiologists independently reviewed the images in terms of the ease of visually discriminating between the AM and index tumor (positive versus negative target sign) and the AM status within the RFA zone. The AM status was divided into AM-plus (completely surrounding tumor), AM-zero (partly discontinuous, without bulging tumor portion), and AM-minus (partly discontinuous, with bulging tumor portion). The McNemar test and kappa statistics were used to compare the CT and MRI data for the incidence of a target sign. The clinical and imaging features were analyzed for the correlation with the local tumor progression using univariate and multivariate analysis.

    Results
    The AM and index tumor were visually discriminated within the ablation zone in 36 (80%) and 40 (88.9%) of 45 ablation zones on MDCT and MRI, respectively (P = 0.387; slight agreement, k = 0.0). On the basis of the results of MDCT and MRI, AM status was classified as AM plus (n = 27 and 31, respectively) and AM zero (n = 9 each). Local tumor progression occurred significantly less in cases with AM-plus on MDCT (P = 0.015) and MRI (P = 0.023) during the follow-up period.

    Conclusion
    MDCT and MRI had equivalent ability to differentiate between the AM and index tumor within the ablation zones immediately after RFA combined with TACE.
    Keywords: Hepatocellular Carcinoma, Radiofrequency Ablation, Transcatheter Arterial Chemoembolization, Combination Therapy, Ablative Margin, MDCT, MRI
  • Seyed Rasool Mirsharifi, Hossein Ghanaati, Morteza Noparast, Sara Farifteh *, Madjid Shakiba, Parto Sabetrasekh Page 14
    Background
    Chronic lower limb arterial stenosis is a condition that impairs the quality of life and could result in amputation. One of the major treatments is angioplasty to open the stenosis.

    Objectives
    We evaluated the midterm results of endovascular treatment of infra popliteal arterial disease as a primary intervention to reduce the level of ischemia in order to avoid major amputation.

    Patients and Methods
    Between March 2013 and April 2015, we collected all data of patients who underwent infrapopliteal angioplasty for chronic limb ischemia (CLI), (Rutherford category 4,5, or 6). The outcome as freedom from reintervention, limb salvage, improvement of signs and symptoms, and the overall survival was analyzed. We reviewed the results of angioplasty by anatomic characteristics of the lesion, transatlantic intersociety characteristics (TASC).

    Results
    Forty seven patients were enrolled in this study of whom 37 were male. Mean age was 67.2 years. Mean ankle brachial index (ABI) before and 6 months after percutaneous transluminal angioplasty (PTA) was 0.5 ± 0.07 and 0.68 ± 0.12, respectively (P < 0.01) and an improved ABI of at least 0.1 was detected in 78% of the patients. In 97.2%, initial technical success was obtained. Rest pain was completely resolved in 66.7% of the patients after the 3-month follow-up and 72.7% after the 6-month follow-up after the procedure. Complete or relative healing of chronic ulcer was seen in 69% and 92% of patients in the 3- and 6-month follow-up after the procedure, respectively. Restenosis occurred in four patients (8.5%), major amputation in 19.1% (9 patients) and the mortality rate was 25.1% (12 cases). Primary patency was finally estimated as 76.1%.

    Conclusions
    PTA for infrapopliteal lesions in high-risk patients can reduce the risk of amputation with a lower mortality and morbidity.
    Keywords: Infrapopliteal, Angioplasty, Limb Ischemia
  • Hamed Naghibi, Babak Shekarchi *, Hamed Bagheri, Amir Reza Azimi, Madjid Shakiba Page 15
    Background
    Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system that causes demyelination or loss of myelin in the white and gray matter of the brain and spinal cord.

    Objectives
    In the current study, the phase sensitive inversion recovery (PSIR) sequence was compared with the other sequences (T2-weighted (T2W), short tau inversion recovery (STIR)) to represent the number and conspicuity of the lesions.

    Patients and Methods
    In this study, 35 MS patients were referred to the imaging center for MRI of the cervical spine. In the sagittal view, T2 weighted turbo spin echo (T2TSE), STIR, and PSIR and in the axial view, T2 TSE, and PSIR sequences were compared. The sequences were compared regarding the number of lesions and conspicuity. P value < 0.05 was considered statistically significant.

    Results
    In sagittal view MRIs, mean plaque number in T2TSE, STIR and PSIR were 1.7 ± 1.1, 3.5 ± 1.4, and 3.4 ± 1.4, respectively (P < 0.001; PSIR and STIR were greater than T2TSE but their difference was not statistically significant). Regarding comparison of imaging conspicuity, most of the plaques in PSIR showed good resolution (75%). In fact, the highest conspicuity of plaques was detected in PSIR (P < 0.001). In axial view MRIs, comparing mean plaque count and conspicuity of lesions, PSIR showed better results than T2TSE (P < 0.001).

    Conclusion
    PSIR sequence showed high sensitivity and precision in the detection of plaques in the cervical spine. PSIR sequence is efficient as a complementary sequence in evaluating the cervical lesions of MS patients. It could increase the diagnostic accuracy in these patients.
    Keywords: Multiple Sclerosis, Cervical, MRI, PSIR
  • Se Hwan Kwon, Yeo Jin Kim, Jehong Yoon, Joo Hyeong Oh, Myung Gyu Song, Tae Seok Seo* Page 16
    Background
    Postpartum hemorrhage (PPH) remains a major cause of maternal morbidity and mortality worldwide. Delayed PPH has received less attention compared to early PPH because the incidence rate of delayed PPH is relatively lower than that of early PPH.

    Objectives
    The aim of this study was to evaluate the clinical manifestations, angiographic findings, and effectiveness of selective transcatheter arterial embolization (TAE) for delayed PPH.

    Patients and Methods
    Selective TAE was performed on 37 women (mean age: 32.1 years, range: 24 - 40) with delayed PPH between March 2006 and October 2016. Delayed PPH was defined as continuous hemorrhage from the female genital tract 24 hours to 6 weeks after delivery. Medical records were retrospectively reviewed for patient characteristics, the time interval between delivery and TAE, angiographic findings, embolized artery, embolic materials, technical and clinical success rate, and complications.

    Results
    Delayed bleeding developed at a median 11.6 days (range: 2 - 34 days) after cesarean section (n = 19) and vaginal delivery (n = 18). On angiography, diffuse hypervascularity was detected in 24 patients, pseudoaneurysm in 11, active extravasation in 1, and arteriovenous malformation in 1. Arteries subjected to TAE included bilateral uterine arteries (UAs) (n = 29), bilateral UAs and unilateral ovarian artery (OA) (n = 4), bilateral UAs and bilateral OAs (n = 1), bilateral UAs and cervicovaginal branch (n = 1), unilateral OA (n = 1), and internal pudendal artery (n = 1). Embolic materials were Gelfoam (n = 30), Gelfoam and coil (n = 3), polyvinyl alcohol (PVA) (n = 2), and PVA and coil (n = 2). There were no procedure-related major complications. Technical success was obtained in all patients (100%), and clinical success was obtained in 34 patients (91.9%)

    Conclusion
    Selective TAE in patients with delayed PPH is a useful treatment with high technical and clinical success.
    Keywords: Postpartum Hemorrhage, Transcatheter Embolization, Interventional Radiology, Angiography
  • Behnaz Moradi, Abbas Ghanbari *, Maryam Rahmani, Mohammad Ali Kazemi, Ahmad, Reza Tahmasebpour, Madjid Shakiba Page 17
    Background
    The sacral region in the fetus can be involved in many pathologies such as spina bifida as the most common spinal abnormality and caudal regression syndrome. On this basis, knowledge about the temporal sequences of sacral ossification centers appearances and other characteristics including bi-iliac distance with newer higher resolution ultrasound technique may be helpful in defining pathologies involving the sacral region and fetal skeletal maturation.

    Objectives
    The goal of this research was to evaluate the timing of ossification of sacral vertebrae and bi-iliac distance as a guidance for clinicians to make an early and reliable diagnosis of sacral region anomalies such as caudal regression syndrome.

    Patients and Methods
    This cross-sectional study was done on 315 normal pregnancies at 14 to 25 weeks of gestational age. The sacral region was evaluated in spine up position, on a coronal plane. By changing the orientation of the probe between sagittal and coronal planes and continuous observation, presence of the ossification center could be confirmed. Then, the level of the central and neural arch centers was recorded in every gestational age.

    Results
    Ossification happened in a predictable caudal direction pattern. S1 and body of S2 were visualized in all cases at 15 - 17 weeks + 6 days and all fetuses with 17 weeks of gestational age. The body of S3 was detected in all cases at 17 weeks and its arch at 20 weeks. Studying all fetuses at 18 weeks of gestation shows sacral ossification in the body and arch of S4. During the study period we had two cases with sirenomelia and three cases with sacral agenesis and we have explained their sacral region findings.

    Conclusion
    By using recent high-resolution ultrasound machines, sacral vertebral ossification centers could be identified in its early gestational age, which could be helpful for earlier detection of sacral pathologies.
    Keywords: Spine, Ossification Center, Ultrasound, Sacral Anomalies, Bi-iliac Distance
  • Keyvan Saneipour, Mojtaba Mohammadpoor * Page 18
    Background
    Magnetic resonance imaging (MRI) plays an important role in clinical diagnosis. The ability of fuzzy c-mean (FCM) algorithm in segmenting MR images has been proven. Some MR images are contaminated with noise. FCM performance is degraded in noisy images. Several efforts are done to overcome this weakness.

    Objectives
    The aim of this study was to propose a new method for MR image segmentation which is more resistant than other methods when noisy MR images are confronted.

    Materials and Methods
    In this study, simulated brain database prepared by BrainWeb was be used for analysis. First FCM and its improvements were analysed and their ability in segmenting noisy MR images were evaluated. Next, knowing that applying genetic algorithm on improver fuzzy c-mean (IFCM) could improve its performance, a new segmentation method was proposed by applying particle swarm optimization on IFCM.

    Results
    The proposed algorithm was applied on some intentionally noise-added MR images. Similarity between the segmented image and the original one was measured using Dice index. Other off-the-shelf algorithms were also tested in the same conditions. The indices were presented together. In order to compare the algorithms’ performances, the experiments were repeated using different noisy images.

    Conclusion
    The obtained results show that the proposed algorithms have better performance in segmenting noisy MR images than existing methods.
    Keywords: MRI Images, Segmentation, Fuzzy
  • Peng Liu, Jie Zhang, Tianhao Su, Zhenghan Yang, Erhu Jin* Page 19
    Objectives
    To quantify pancreatic fat content (PFC) in patients with newly diagnosed type 2 diabetes mellitus (T2DM) using proton magnetic resonance spectroscopy.

    Patients and Methods
    Spectra of the pancreatic head, body, and tail were acquired by single-voxel point-resolved spectroscopy sequences on a 3.0-T magnetic resonance scanner in 59 newly diagnosed T2DM patients and 32 non-diabetics (controls). PFC values were calculated and compared between the patients and controls as well as among the head, body, and tail. Correlations were determined between PFC and age, body mass index (BMI), and serum triglyceride (TG) levels.

    Results
    Mean fat fractions did not differ significantly (all Ps > 0.05) across the pancreatic head, body, and tail in either the T2DM group (15.14 ± 7.49%, 17.51 ± 7.74%, and 18.35 ± 7.58%, respectively) or the control group (12.27 ± 7.85%, 15.35 ± 8.53%, and 16.20 ± 10.02%, respectively). Overall, mean PFC values did not differ significantly (P > 0.05) between the T2DM group (16.82 ± 6.16%) and control group (14.56 ± 7.97%). Among T2DM patients, PFC did not correlate with age, TG levels, or BMI (r < 0.15, P > 0.05). Among non-diabetic controls, PFC correlated with BMI (r = 0.362, P = 0.042) and TG levels (r = 0.467, P = 0.007), but not with age (r < 0.15, P > 0.05).

    Conclusion
    PFC in the head, body, and tail are similar for newly diagnosed T2DM patients and non-diabetic persons. PFC does not correlate with age, TG, or BMI in newly diagnosed T2DM patients.
    Keywords: Pancreatic Fat, Quantitative Study, Type 2 Diabetes Mellitus, Proton Magnetic Resonance Spectroscopy
  • Guobing Liu, Yan Hu, Lifang Pang, Haojun Yu, Pengcheng Hu, Hongcheng Shi * Page 20
    Background
    The impact of volume-of-interest (VOI) placement on liver standardized-uptake-value (SUV) measurement remains unclear.

    Objectives
    To investigate variability and reliability of liver SUV in relation to placement of VOI within the right lobe of the liver.

    Patients and Methods
    Positron emission tomography-computed tomography (PET/CT) of 343 patients with normal liver were retrieved. Liver mean SUV (SUVmean) were measured by placing spherical VOIs at upper, portal vein and lower level of the right-lobe liver. The general linear model, Bland-Altman analysis, one-way ANOVA were performed and the intraclass correlation coefficients (ICC) were calculated to identify impacts of reader and VOI position on variations of liver SUVmean.

    Results
    The liver SUVmean at the upper, lower and portal vein level were 1.85 ± 0.435, 1.88 ± 0.409, and 1.89 ± 0.414, respectively, with no significant inter-location difference (P = 0.449). The coefficients of variation were close among locations (21.9% - 23.5%). The inter-location ICCs controlling for reader were 0.955 for reader 1 and 0.980 for reader 2, while the inter-reader ICCs controlling for location were between 0.930 and 0.937, indicating great reliability and reproducibility. However, inter-reader bias of SUVmean were significantly different among locations (P < 0.001). Bias at portal vein level (0.069 ± 0.112) was significantly larger than those at the upper level (0.004 ± 0.144, P < 0.001) and lower level (0.002 ± 0.136, P < 0.001).

    Conclusion
    Liver SUVmean measured by placing VOI at the portal vein level exhibited a relatively larger variation and less precision between readers, which was not recommended.
    Keywords: 2-Fluoro-2-Deoxy-D-Glucose, Positron Emission Tomography, Computed Tomography, Standardized Uptake Value, Liver