فهرست مطالب

Iranian Journal of Radiology - Volume:16 Issue: 1, 2019
  • Volume:16 Issue: 1, 2019
  • تاریخ انتشار: 1397/10/25
  • تعداد عناوین: 20
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  • Peiji Song, Jing Qin, Yamei Yu, Chuanying Shi, Penggang Qiao, Anming Xie, Gongjie Li* Page 1
    Background
    Recently, magnetic resonance angiography (MRA) has been widely used for the detection of moyamoya disease (MMD). However, the diagnostic performance of MRA in the detection of the affected artery in MMD remains unclear.
    Objectives
    To assess the diagnostic performance of MRA in detecting internal carotid artery (ICA), anterior cerebral artery (ACA), middle cerebral artery (MCA) or posterior cerebral artery (PCA) involvement (including stenosis and occlusion) compared with digital subtraction angiography (DSA) in pediatric MMD. Patients and
    Methods
    Fifty-eight pediatric patients diagnosed with MMD by MRA and DSA within one week from September 2010 to September 2011 were evaluated.
    Results
    Among 261 vessels of occlusion demonstrated by MRA, 48 vessels of stenosis were confirmed by DSA. There was a similar detection rate of vascular lesions by MRA and DSA in ICA, ACA and PCA. More lesions in MCA were detected as occlusion by MRA than DSA. MRA was more sensitive and accurate in diagnosing vascular lesions, including ICA, ACA and MCA, while it was most specific and lowest sensitive was found in diagnosing PCA. In addition, MRA was moderate to highly consistent with DSA in diagnosing MCA and PCA.
    Conclusion
    MRA had an important diagnostic value in the detection of the affected ICA, ACA, MCA and PCA with DSA as the gold standard, but with an overestimated evaluation of stenosis severity in pediatric MMD.
    Keywords: Moyamoya Disease, Digital Subtraction Angiography, Magnetic Resonance Angiography
  • Hamidreza Saligheh Rad , Mojtaba Safari , Anahita Fathi Kazerooni , Yashar Moharamzad , Morteza Sanei Taheri * Page 2
     
    Background
    Apparent diffusion coefficient (ADC) measured by diffusion-weighted MRI and first-order histogram (FOH) extracted features, as markers of tumor heterogeneity, have been implicated in differentiating grade of the intracranial tumors.
    Objectives
    To examine whether ADC, normalized ADC (NADC), and FOH features such as entropy, kurtosis, and uniformity can differentiate benign vs. malignant meningioma. Patients and
    Methods
    MRI with diffusion-weighted (DW) imaging sequence of 62 patients with histologically-proven meningioma (37 benign and 25 malignant/atypical) were included. After co-registration of ADC maps to their corresponding anatomical MRI (post-contrast T1-weighted [T1C] images) and delineation of the tumors border by selecting regions of interest (ROIs) on T1C images, a mask of tumor was created and overlaid on the corresponding ADC map. Then, FOH features were extracted.
    Results
    Mean (± standard deviation [SD]) ADC values in benign and malignant subgroups were respectively 1.05 (± 0.23) and 0.99 (± 0.29) 10-3 mm2/s, and P = 0.69. NADC ratios were not statistically significant between benign (0.5 ± 0.09) and malignant (0.5 ± 0.07) meningioma groups (P = 0.89). Mean values of entropy (6.36 vs. 6.44), kurtosis (5.77 vs. 5.45), and uniformity (536.8 vs. 304.18) were comparable between benign and malignant meningioma subgroups. Receiver operating characteristic (ROC) curve analysis did not yield the significant area under the curve results to show acceptable diagnostic accuracy for any of the measured variables.
    Conclusion
    ADC, NADC, and statistical features of tumor heterogeneity by FOH method measured by DW-MRI were not able to differentiate benign vs. malignant/atypical meningiomas.
    Keywords: Diffusion Magnetic Resonance Imaging, Meningioma, Apparent Diffusion Coefficient, Histogram, Tumor
  • Necla Eryilmaz, Mehmet Ali Eryilmaz, Serdar Arslan*, Ibrahim Solak, Selma Pekgor, Aysegul Altunkeser, Ethem Omeroglu Page 3
     
    Background
    Idiopathic granulomatous mastitis (IGM) is a rare and benign chronic inflammatory breast disease. The disease is usually associated with recurrent attacks and may result in the formation of fistulas. Fistula or ulceration on the skin of the breast makes it difficult to medication treatment and may necessitate extensive skin excision in patients undergoing surgery.
    Objectives
    This study aimed to compare the clinical and radiological findings between fistular and non-fistular idiopathic granulomatous mastitis. Patients and
    Methods
    The clinical and radiologic findings of 52 women with a histopathology diagnosis of idiopathic granulomatous mastitis were retrospectively evaluated. All the patients were assessed using ultrasonography and magnetic resonance imaging. Of the 52 patients, 20 underwent mammography. The findings in patients with fistular and non-fistular idiopathic granulomatous mastitis were compared.
    Results
    Erythema, ulceration, and nipple changes were more common in patients with fistular idiopathic granulomatous mastitis. While the most common finding in ultrasounography in fistular IGM patients were collection areas with complicated cysts consistent with abscess, the finding in non-fistular IGM patients were multiple irregularly shaped hypoechoic masses. In magnetic resonance imaging, the most common finding in fistular IGM patients was non-mass lesions with regional clustering ring enhancement, whereas the most frequent finding in non-fistular IGM patients was non-mass lesions with regional heterogeneous enhancement. There were statistically significant differences between findings of both groups.
    Conclusion
    There are differences in the clinical and radiologic findings of fistular and non-fistular idiopathic granulomatous mastitis. Ultrasonography and magnetic resonance imaging could be useful in identifying patients with a high risk of developing fistulas.
    Keywords: Idiopathic Granulomatous Mastitis, Fistula, Ultrasonography, Magnetic Resonance Imaging
  • Robert Marterer*, Sebastian Tschauner , Gernot Grangl , Peter Kalmar , Erich Sorantin Page 4
     
    Background
    Assessment of cardiac performance parameters in patients with corrected tetralogy of Fallot with cardiac MRI short axis method compromises critical elements including papillary muscles, determination of end-diastolic and end-systolic cardiac phase, and furthermore, selection of the basal plane.
    Objectives
    The study purpose was to evaluate the impact of basal plane selection on resulting cardiac performance parameters in cardiac MRI. Patients and
    Methods
    Cardiac MRI examinations of 26 patients (mean-age: 20.7 years ± 7.8) with corrected tetralogy of Fallot were analyzed retrospectively. In post-processing, selection of end-diastolic and end-systolic phase was performed manually by visual determination of largest/smallest ventricular cavities. End-diastolic volume, end-systolic volume, and stroke volume were then calculated for both ventricles. Afterward, initially selected basal planes were systematically varied by one slice, and resulting volumes were compared. This retrospective study was conducted under approval of the institutional review board without patient informed consent.
    Results
    Variations of the basal plane caused significant changes (P < 0.005) of end-diastolic and end-systolic volumes. Differences were as large as 15.2% ± 5.8 regarding the left ventricle and up to 17.4% ± 6.1 for the right ventricle. Consequently, calculated stroke volume changed up to 19.2% ± 6.3 for the left and 22.7% ± 7.2 for the right ventricle. Ejection fractions of both ventricles varied significantly (P < 0.005). These differences were up to 19.1% ± 8.2.
    Conclusion
    Variation of the basal plane by just one slice in cardiac MRI short axis method led to significant changes in the resulting cardiac performance parameters of both ventricles in patients with corrected tetralogy of Fallot.
    Keywords: Magnetic Resonance Imaging, Congenital Heart Defects, Cardiac Imaging Techniques
  • Jie Jiang Shu, Juan Li, Li Wu, Wen Zhao, Dan Han * Page 5

        Background: Laryngeal cancer stage is essential for determining the appropriate treatment strategies and evaluating prognosis for laryngeal carcinoma, which is based primarily on laryngeal cartilage invasion or not. However, there was no optimal means to confirm whether cartilage was being invaded before operation. With dual-energy CT development, it provided a new potential approach for laryngeal cartilage invasion diagnosis. Objectives: To evaluate the clinical value of dual-energy computed tomography with iodine overlay images and spectrum curve in the quantitative analysis of laryngeal cartilage invasion in patients with laryngeal carcinoma. Patients and Methods: Dual-source dual-energy CT was performed for one hundred and twenty patients with confirmed diagnosis of laryngeal carcinoma by surgical pathology (56 cases with laryngeal cartilage invasion and 64 cases without invasion). The mean CT attenuation values of laryngeal cartilage and the tumor in routine scan, arterial and venous phases was measured and cartilage invasion was considered to be present with asymmetric sclerotic changes, erosion, lysis and extralaryngeal tumor spread with iodine overlay images and routine scan images. Moreover, the sensitivity and specificity were analyzed. The slope of spectral curve and iodine concentration of the tumors, invaded laryngeal cartilage and non-invaded laryngeal cartilage were compared between arterial phase and venous phase. Furthermore, the receiver operating characteristic (ROC) curve of mean CT attenuation value, the slope of spectral curve and iodine concentration were made comparative analysis. Results: The mean CT attenuation values of the tumors, invaded laryngeal cartilage and non-invaded laryngeal cartilage had significant difference among the routine scan, arterial phase and venous phase (P < 0.05). The sign of asymmetric sclerotic changes had no significant difference between iodine overlay images and routine scan images (the same specificity and sensitivity, 77.8% and 52.6%, respectively). However, the signs of erosion, lysis and extralaryngeal tumor spread had significant difference. The specificity and sensitivity of iodine overlay images were superior to that of the routine scan images in the three signs (specificity and sensitivity of erosion: 92.3% vs. 61.5%, and 86.7% vs. 60.0%, respectively; lysis: 82.4% vs. 69.2%, and 81.8% vs. 66.7%, respectively; extralaryngeal tumor spread: 90.9% vs. 68.3%, and 100% vs. 63.5% respectively). The slope of spectral curve and iodine concentration of the tumors, invaded laryngeal cartilage and non-invaded laryngeal cartilage showed significant difference (P < 0.05). The iodine concentration of the tumor was higher than invaded laryngeal cartilage. The area under the curve (AUC) value of mean CT attenuation value in routine scan, arterial phase and venous phase were 0.064, 0.265, and 0.192, respectively. The AUC value of the slope of spectral curve in arterial phase was 0.970 and its selected cutoff was considered as 1.09. In this cutoff point, the diagnostic indices including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 88.9%, 100%, 100%, and 82.6%, respectively, while the AUC value of the slope of spectral curve in venous phase was 0.944 and its selected cutoff was considered as 0.95. In this cutoff point, the diagnostic indices including sensitivity, specificity, PPV, NPV, positive likelihood ratio (PLR), negative likelihood ration (NLR) were 81.5%, 96.3%, 91.7%, 77.3%, 7.76, and 19.30, respectively. The AUC value of the slope of iodine concentration in arterial phase was 0.995 and its selected cutoff was considered as 1.05. In this cutoff point, the diagnostic indices including sensitivity, specificity, PPV and NPV were 92.6%, 100%, 95.8%, and 100%, respectively. Moreover, the AUC value of the slope of iodine concentration in venous phase was 0.905 and its selected cutoff was considered as 0.75. In this cutoff point, the diagnostic indices including sensitivity, specificity, PPV, NPV, PLR, and NLR were 77.8%, 88.9%, 91.3%, 82.6%, 7.00, and 24.5, respectively. Conclusion: Dual-energy CT can provided a new potential approach for laryngeal cartilage invasion diagnosis in order to guide the selection of optimal operation plan and improve the prognosis.

    Keywords: Laryngeal Carcinoma, Invasion, Iodine Concentration, Iodine Overlay, Spectral Curve
  • Paul Flechsig*, Heike Zabeck , Sebastian Reubold , Christos Sachpekidis , Hendrik Rathke , Manuel R, amp, ouml, hrich , Tim Holland, Letz , Claus, Peter Heussel , Alexander Harms , Hans, Ulrich Kauczor , Uwe Haberkorn, Frederik L. Giesel Page 6
           
    Background
    Regarding mediastinal N-staging in lung cancer patients, computed tomography (CT), magnetic resonance imaging (MRI), and integrated 18Fluorine-fluorodeoxyglucose-positron emission tomography/CT (18F-FDG-PET/CT) are the most widespread imaging methodologies in clinical routine.
    Objectives
    In order to further extract information from non-invasive staging, we evaluated the use of 18F-FDG-PET/CT and dynamic contrast enhanced (DCE) and diffusion-weighted imaging (DWI) MRI using histopathology as the diagnostic gold standard. Patients and
    Methods
    A total number of 50 patients had undergone MRI of the chest within two weeks prior to surgery for histopathological proof. DCE-MRI was evaluated on the basis of region of interest (ROI)-based signal intensity/time (SI/T) curves in the respective mediastinal lymph nodes (LNs). In total, 28 LNs could be allocated to the corresponding histopathological findings, as well as to corresponding findings in 18F-FDG-PET/CT.
    Results
    Malignant LNs presented with significantly higher FDG uptake in PET. Significant differences between malignant and benign LNs were found for DCE-MRI regarding the parameters MaxE, 4-minutes value, SE, EP and EP/MaxE. In DWI-MRI, malignant LNs presented with significantly lower signal intensity compared to benign LNs (p < 0.01). An apparent diffusion coefficient (ADC) threshold of 1528 mm2/s was found to exclude malignancy for LNs that are above the threshold.
    Conclusion
    18F-FDG-PET in addition with MRI that includes DWI might improve mediastinal N-staging, which is of interest in cases of FDG-equivocal LNs. An ADC threshold of 1528 mm2/s might potentially help to further classify LNs with indefinite PET-findings. DCE-MRI of mediastinal LNs seems not yet to be approved for clinical routine.
    Keywords: Lung Cancer, staging, FDG-PET, CT, Magnetic Resonance Imaging, DWI
  • Ahmet Kursad Poyraz*, Mehmet Ruhi Onur , Yesim Eroglu , Murat Gurger , Mehmet Cagri Goktekin , Gurkan Akgol Page 7
       
    Background
    Low-dose computed tomography (CT) is the preferred method for post-reduction evaluation of hips of infants in spica casts, but the assessment of acetabular morphological features in developmental dysplasia of the hip (DDH) using CT has not be done before.
    Objectives
    To determine CT imaging characteristics of the acetabulum in DDH and to be able to determine DDH in pelvic CT examinations performed for different purposes. Patients and
    Methods
    CT images of 102 consecutive patients with DDH (90 females, 12 males) and 51 age-matched controls (26 females, 25 males) were included in this study. Acetabular shape abnormalities, surface irregularity, subcortical sclerosis, shallowing, and measurement of acetabular cortical bone thickness were evaluated in coronal reformatted images. Differences in the cortical thickness of dysplastic and normal hips were assessed.
    Results
    Forty-four patients (43.1%) had unilateral and 58 had bilateral DDH (56.9%). Acetabular margin irregularity was present in all patients with unilateral DDH and 55 of the 58 patients with bilateral DDH (94%). Thickening on the inferior part of the ilium compared to the normal side was seen in 41 of the 44 unilateral DDH patients (93%). In the 44 patients with unilateral DDH, the mean cortical thickness measured from the central part of the acetabulum was 0.86 ± 0.03 mm and 0.65 ± 0.03 mm on the normal and dysplastic sides, respectively (P = 0.0001). This difference was more distinct at the acetabular rim, measuring 1.11 ± 0.06 mm and 0.70 ± 0.04 mm on normal and dysplastic sides, respectively (P = 0.0001).
    Conclusion
    Acetabular marginal irregularity and flattening is a reliable finding in the diagnosis of DDH when combined with thickening on the inferior part of ilium and will help in the diagnosis of DDH in patients older than 6 months old with a pelvic CT scan due to diseases other than DDH.
    Keywords: Developmental Dysplasia of the Hip, Computed Tomography, Acetabulum, Ultrasound, Margin
  • Chao Xiang , Qianxue Chen , * Yunfei Zha Page 8
     
    Background
    The treatments of primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM) are different; therefore, accurate diagnosis is crucial for the therapeutic planning. Although there is overlap of features on conventional magnetic resonance (MR) images between PCNSL and GBM, the PCNSL has specific features, which are different from those of GBM on conventional MR images.
    Objectives
    The current study aimed at characterizing specific features of PCNSL by comparing them with conventional MR images of GBM, and improving diagnostic accuracy at the time of initial presentation. Patients and
    Methods
    The current study retrospectively evaluated the conventional MR images of 21 immunocompetent patients with PCNSL and 13 patients with GBM pathologically proven in Renmin Hospital of Wuhan University, Wuhan, China from January 2014 to March 2017. All patients were subjected to non-contrast and contrast enhanced MRI. Tumor location, quantity, and morphology, as well as common and specific features and patterns, peritumoral edema, and hemorrhage were recorded and compared.
    Results
    Twenty-one patients with PCNSL exhibited 44 lesions, and 13 patients with GBM exhibited 16 lesions. PCNSL affected both infra- and supratentorial regions, while GBM only affected supratentorial regions. Deep white matter, basal ganglia, periventricular areas, and the corpus callosum were the most common sites in PCNSL. Homogeneous enhancement was presented in 95.2% of PCNSL, and all GBM lesions showed heterogeneous enhancement. PCNSLs had various appearances, whereas most of the GBMs (81.3%) had a mass-like appearance. Differences in intratumoral hemorrhage (P < 0.001), necrotic or cystic components (P < 0.001), and intratumoral vascular enhancement (P < 0.001) between PCNSL and GBM were statistically significant. “Notch sign” and open-ring enhancement were specific features for PCNSL.
    Conclusion
    PCNSL has specific features, patterns, and locations. These features and patterns can be helpful to differentiate PCNSL from GBM at the time of initial presentation
    Keywords: Extraventricular, Glioblastoma, Lymphoma, MRI
  • Jiyu Liu , Jing Gong , Lijia Wang , Xiwen Sun, Shengdong Nie * Page 9
     
    Background
    In order to evaluate the growth rate of lung cancer, pulmonary nodule segmentation is an essential and crucial step. Segmentation of juxta-pleural pulmonary nodule in CT scans, especially small size ones, is still a challenge.
    Objectives
    To better support the following radiomics analysis, this study aims to propose and develop a novel segmentation method for small-size juxta-pleural pulmonary nodules.
    Materials and Methods
    In this study, we investigated and developed a novel approach based on transition region thresholding and chain code analysis to segment juxta-pleural pulmonary nodules. First, we cropped the region of interest (ROI) from the lung CT scans, and enhanced the nodule regions by using an anisotropic diffusion algorithm. Second, to extract the foreground pixels (including the attached chest wall) from ROIs, we applied an adaptive segmentation process by incorporating a threshold segmentation method with transition region analysis. Third, we smoothed the lung contour by using iterative weighted averaging algorithm. Then, we utilized chain code analysis to repair lung parenchyma boundaries. Finally, we obtained the segmentation result by overlapping the extracted foreground with the repaired lung parenchyma mask.
    Results
    To validate the performance of the proposed segmentation approach, we selected 50 juxta-pleural nodules with diameter ranges from 5 mm to 10 mm from Lung Image Database Consortium (LIDC) database. Compared with the ground truth generated by radiologists, we achieved an average overlap rate of 76.93% ± 0.06 with a false positive rate of 13.09% ± 0.09.
    Conclusion
    After comparing and analyzing the segmentation results, we found that our approach outperformed the method reported in other literature. The experimental results demonstrated that our new method is an effective approach to segment small-size juxta-pleural pulmonary nodules accurately.
    Keywords: Pulmonary Nodule, Image Segmentation, Transition Region, Iterative Weighted Averaging, Chain Code
  • Jun Yang , Qinqing Li * Page 10
     
    Background
    Although CT morphological characteristics of giant cell tumors (GCTs) of the sacrum have been reported in the literature, the enhanced CT quantitative characteristics of GCTs have not been extensively evaluated.
    Objectives
    The aim of our study was to analyze the enhancement characteristics of giant cell tumors of the sacrum. Patients and
    Methods
    Sixty-one cases were reviewed, including 20 GCTs, 22 sacral chordomas (SCs) and 19 sacral schwannomas (SSs). The CT images of all the three types of tumors were retrospectively analyzed. The enhancement index (EI) of each mass was calculated by the formula: EI(a/v) = [D(a/v) - D(pre)]/D(pre), where D(a/v) was the density of the mass on the enhanced CT (a = arterial phase; v = portal venous phase), and D(pre) was the density of the mass on the pre-enhanced images. The maximum enhancement (Emax) was determined by the following equation: Emax = D(v) - D(pre). The parameters of the different enhancement phases among the 3 groups were compared with One-way ANOVA.
    Results
    On the noncontrast images, the densities of the SCs were lower than those of the GCTs and SSs, but there was no difference between the GCTs and SSs (P > 0.05). In the arterial phase, the EIa of the GCTs was the highest among the three groups (P < 0.05), and that of the SCs was the lowest. In the venous phase, the EIv of the GCTs was higher than that in the arterial phase and was also the highest among the three groups (P < 0.05). A difference was found among the groups, namely, the GCTs, SCs, and SSs (P < 0.05). The EIa and EIv of the SCs were the lowest among the three groups. The Emax of the GCTs was the highest among the three groups (P < 0.05).
    Conclusion
    Quantitative analysis of the characteristics of contrast-enhanced CT is a useful method for diagnosing sacral GCTs and differentiating these tumors from SCs and SSs.
    Keywords: Giant Cell Tumor, Sacrum, Chordoma, Schwannoma, Computed Tomography, Enhancement
  • Jin Fang, Honglin Li, Minjie Liang, Dabiao Deng, Quan Zhou * Page 11

     

    Background

    Computed tomography (CT) lung perfusion scan could be used to evaluate regional, morphologic, and functional changes in chronic obstructive pulmonary disease (COPD) noninvasively. However, the dual hemodynamic changes in severe COPD patients have not been studied quantitatively using CT lung perfusion scan.

    Objectives

    To determine the dual hemodynamic changes quantitatively in patients with severe COPD by using low-dose CT lung perfusion scan. Patients and

    Methods

    Fifteen patients with severe COPD (global initiative for chronic obstructive lung disease [GOLD] class IV) and 31 controls were enrolled. All participants received low-dose CT lung perfusion scan using a Toshiba 320-detector row dynamic volumetric CT. The perfusion parameters including pulmonary artery flow (PAF), bronchial artery flow (BAF), perfusion index [PI = PAF/(PAF + BAF)] and time to peak (TTP) of the time density curve were generated and compared between the impaired lung parenchyma in the COPD group and normal lung parenchyma in the control group.

    Results

    The PAF and PI values in the COPD group were significantly lower than that in the control group (P < 0.001, P < 0.001), while the BAF value was significantly higher (P < 0.001). The TTP of impaired lung parenchyma was significantly prolonged compared to the normal lung parenchyma (P < 0.001).

    Conclusion

    Patients with severe COPD have distinct changes in pulmonary dual hemodynamics. Low-dose lung perfusion scan using a 320-detector row dynamic volumetric CT could be used to evaluate the pulmonary dual hemodynamics

    Keywords: Chronic Obstructive Pulmonary Disease, Dynamic Volumetric CT, Perfusion
  • Sepideh Sefidbakht , Banafsheh Zeinali, Rafsanjani , Maryam Safari , Fariba Zarei , * , Bijan Bijan , Reza Jalli , Maryam Kasraeian , Homeira Vafaei, Cisakht, Nasrin Asadi Page 12
     
    Background
    Recently there have been attempts to link fetal growth retardation to placental morphology as well as apparent-diffusion coefficient (ADC) values.
    Objectives
    The purpose of this study was to investigate the possible correlation of apparent diffusion coefficient (ADC) values of normal placentas with different gestational ages and various Grannum grades (Gg). Patients and
    Methods
    Thirty-eight women were included in this study. All women with singleton pregnancies referred for fetal MRI who were proven normal in pre/postnatal follow-up were included in the study. All placentas were evaluated by ultrasound trans-abdominally. The placenta was assessed for maximal thickness, subjective shape, presence of possible infarcts, sub-placental, and subchorionic hemorrhage. Placentas were also evaluated for G-grading and signal intensities in T2 half-fourier acquisition single-shot turbo spin-echo (HASTE) images. Diffusion weighted imaging (DWI) images were done using two b-value sets (0, 1000 and 50, 400, 800). Largest possible regions of interest (ROI) were drawn over the placenta and ADC values were correlated with gestational-age and Gg using linear regression and Kruskal-Wallis, respectively.
    Results
    There were 11, 18, 9, 0 patients with normal looking placentas with Gg of 0, 1, 2, and 3 respectively. ADC values obtained from b values of 0, and 1000 show a significant correlation with gestational-age (R2 = 0.60, P = 0.000) and Gg (P = 0.004) respectively, while ADC values obtained from b values of 50, 400, and 800 did not show significant correlation with gestational age (R2 = 0.087, P = 0.073) or Gg (P = 0.236).
    Conclusion
    ADC values which were obtained from sets of b values of 0 and 1000 correlated with placental maturity (both gestational age (GA) and Grannum grades). This can be attributed to lower b-values covering the microperfusion in addition to diffusion characteristics of the tissue.
    Keywords: ADC Value, Gestational Age, Grannum Grades, Placenta
  • Yumi Kim , Bong Joo Kang*, Jung Min Lee , Sung Hun Kim Page 13
     
    Background
    Computer-aided diagnosis (CAD) as an adjunct to breast ultrasonography (US) has been extensively developed using different breast imaging techniques to help improve radiologists’ diagnostic performance, particularly in distinguishing malignant from benign breast lesions. Additionally, quantitative variables can be obtained using CAD.
    Objectives
    The aim of this study was to evaluate the usefulness of CAD as an adjunct to breast US by exploring the diagnostic performance of US and CAD using the breast imaging reporting and data system (BI-RADS) descriptors and quantitative variables. Patients and
    Methods
    Between October 2015 and December 2016, we performed breast US with CAD (S-Detect) for screening or diagnostic purposes. We assessed the diagnostic performance according to the BI-RADS descriptors, quantitative variables (width, height, height/width (H/W) ratio, area, and depth), and combined results. We analyzed the agreement in the descriptors between US and CAD.
    Results
    Four hundred thirty-two women with 521 breast lesions were enrolled. The area under the receiver operating characteristic curve (AUC), sensitivity, and specificity of US vs. CAD were 0.82 vs. 0.78, 95% vs. 78%, and 69% vs. 78%, respectively. When CAD was combined with breast US, the specificity was significantly improved from 69% to 72% (P < 0.05). Among all descriptors and quantitative variables, the height and H/W ratio exhibited the greatest AUC (0.76 and 0.75), and the H/W ratio had the highest sensitivity (90%). According to the concordance analysis, the orientation exhibited the greatest agreement (k = 0.57).
    Conclusion
    Using CAD, we could accurately determine the BI-RADS descriptors, quantitative variables and improve the specificity. Additionally, the orientation and H/W ratio are consistent key factors for both US and CAD.
    Keywords: Ultrasonography, Breast Neoplasms, Diagnosis, Computer-Assisted
  • Ay?egül Altunkeser*, Ender Alkan , O?uzhan Günenç , ?smet Tolu , Muslu Kaz?m K?rez Page 14
     
    Background
    The placenta is a soft organ with vital importance. Increased placental stiffness was reported in pathological conditions emerging during pregnancy, such as diabetes mellitus and hypertension. Nowadays, placental stiffness can be quantitatively measured using the shear wave elastography (SWE) technique.
    Objectives
    We aimed to assess the factors affecting elasticity by finding the normal elastogram values of healthy pregnancy placentas using the SWE technique due to the importance of early diagnosis in risky pregnancies. Patients and
    Methods
    In total, 288 healthy pregnant women in the second or third trimester were included in our prospective study. The pregnant women who had pathology in their fetus and its appendices or a posteriorly located placenta were excluded from the study. Obstetric ultrasonography and a placental elasticity assessment were performed in all the pregnant women. Speed values were obtained from five different locations of the placenta, including the central S1, S2, S3, S4 and peripheral P regions. The elasticity of the regions were compared, and the factors affecting elasticity were investigated.
    Results
    There were significant differences among the velocity values obtained from five different areas of the placenta. The mean velocity values obtained from the central region were higher than those of the peripheral region (P < 0.001). There was also a significant difference in the mean velocity measurements obtained from the central region (P < 0.001). The hardest region of the placenta was the maternal surface, while the softest region was the peripheral surface. The elastographic velocity values of the placenta were found to correlate with maternal age, body mass index, placental localization, thickness, and grade, whereas it did not correlate with gravidity, parity, gestational week, and amniotic fluid index .
    Conclusion
    The elasticity of the placenta varied according to the region and surface, whereas it did not change according to gestational week. It may be convenient to use the elasticity values obtained by SWE from specified regions in the follow-up of placentas in high-risk pregnancies. However, considering the affecting factors and contradictory study results, a large number of large-scale studies is required to strengthen the efficiency of SWE in the placental assessment
    Keywords: Shear Wave Elastography, Placental Elasticity
  • Zahra Alirezaei*, Keyvan Jabbari , Tohid Dehghani , Mohammadbagher Tavakoli , Mojdeh Mehdizadeh , Nafiseh Berenjkoob , Reihane Faraji Page 15
     
    Background
    Cone beam computed tomography (CBCT) has been broadly acceptable in recent years as a radiography modality for diagnosis, treatment planning and follow up in dentistry. Some important parameters such as radiation dose, image quality and field of view are considered as a criteria for deciding whether or not a CBCT dental unit is suitable for a particular application.
    Objectives
    This study aims to evaluate the effect of exposure levels on the absorbed dose of mandible and salivary glands according to various settings of milliamperage (mA) in CBCT.
    Materials and Methods
    A very advanced multilayers head and neck phantom was constructed for this study. This phantom was built based on the CT images of a specific patient with an average size. This phantom was constructed using proper substitutes for soft tissue and bone according to their physical properties. Therefore, there was a high level of agreement with the patient's body. This phantom enables us to measure the absorbed dose inside the organs. Dosimetry has been performed by Soredex Cranex3d CBCT. For film dosimetry, AGFA films were used in various layers of the phantom. The mAs of the device was changed in the range of 2, 4, 6, 8, 10 and 12 mA.
    Results
    The maximum and the minimum absorbed dose was placed in the area related to the right mandible and the left submandibular gland. The increase of absorbed dose by mA increase was meaningful in the confidence level of 95% for all scanned areas. By changing mA from 2 to 12, the absorbed dose varied significantly with a maximum 5.44-fold variation between the highest and lowest dose for the parotid gland.
    Conclusion
    This study has shown that there is a meaningful relationship between the increase of mA and increase of absorbed dose in different parts of the dentomaxillofacial area, including the mandible, submandibular and parotid glands. It is concluded that as long as the image quality is acceptable for diagnostic purposes, the mAs of the CBCT should be kept in a low range to minimize the absorbed dose.
    Keywords: Absorbed Dose, CBCT, Radiation Setting, Head Phantom
  • Serife Leblebisatan*, Bozkurt Gulek , Gokhan Soker Page 16
    Objectives
    The purpose of this study was to detect the types and prevalences of vena cava variations, as well as looking for gender differences and associating anomalies. Patients and
    Methods
    The computed tomography (CT) images of 5763 patients who had undergone thorax and abdominal CT examinations were evaluated retrospectively for superior vena cava (SVC), inferior vena cava (IVC), and left renal vein (LRV) variations.
    Results
    Vena cava variations were detected in 637 (11%) patients. SVC variations were present in 15 (0.26%) patients, while 36 (0.64%) patients had IVC, and 596 patients (10.34%) had LRV variations. It was also shown that there was no difference between the prevalences of the variations in terms of gender difference. When associating anomalies were evaluated, it was seen that there was a significant increase in the risk of observing the horseshoe kidney anomaly in patients with retroaortic left renal vein (RALRV) variation.
    Conclusion
    Vena cava variations are not rare. When present, they may coexist with other vena cava variations or other variations. These variations can easily be detected on CT. Properly characterizing and classifying IVC variations is crucial for proper planning of surgical interventions and transvenous interventions to prevent serious complications and failures.
    Keywords: Inferior Vena Cava (IVC), Left Renal Vein (LRV), Superior Vena Cava (SVC), Vena Cava
  • Yu Yang * Page 17

      Bladder leiomyoma is a rare benign neoplasm that may mimic a malignant lesion in medical images. We report a woman with bladder leiomyoma who was correctly diagnosed by contrast-enhanced ultrasound (CEUS). The patient was referred to our hospital after a bladder neoplasm was detected during a health checkup. CEUS showed fast wash-in and slow wash-out in the tumor, similar to a normal bladder wall. To conclude, bladder leiomyoma has its specific characteristics on CEUS, and this modality may be a good option for diagnosis of bladder leiomyoma.

    Keywords: Bladder Leiomyoma, Contrast Agent, Ultrasound
  • Seonghwan Byun , Kyung Eun Shin*, Jai Soung Park , Heon Lee , Jae Wook Lee , Susie Chin , Eun Suk Koh Page 18
    Immunoglobulin G4-related disease is a novel inflammatory entity involving multiple organs of the body. In the lungs, it is accompanied by infiltration of IgG4-positive lymphocytes and increased serum levels of IgG4. Previous studies have reported radiological findings of IgG4-related lung disease in the pulmonary parenchyma; however, there are few case reports of pleural involvement. Here, we report the case of a 66-year-old man with IgG4-related disease unilaterally involving the lung interstitium and pleura. Thoracic computed tomography images demonstrated pleural effusion and thickening resembling a primary or secondary pleural malignancy. The diagnosis of IgG4-related disease was confirmed by video-assisted-thoracoscopic biopsy. This rare disease should not be overlooked in patients with radiological findings that are suggestive of pleural malignancies.
    Keywords: Immunoglobulin G, Pleural Disease, Pleural Effusion, Plasma Cells
  • Houman Sotoudeh * Page 19

    CT perfusion (CTP) is an evolving protocol for stroke evaluation in many hospitals, but there are several pitfalls in CT perfusion. Herein I present a patient suspicious of brain infarction under “stroke code”. CT perfusion was initially visually interpreted and because of obvious asymmetry between the right and left cerebral hemispheres the interpretation was consistent with right cerebral ischemia. CT angiogram (CTA) did not demonstrate significant vascular stenosis. Subsequent electroencephalography (EEG) was consistent with status epilepticus from the left cerebral hemisphere. Since more and more CTPs are now performed in acute setting of code stroke more patients are being imaged with ongoing seizure with increased perfusion in epileptogenic brain parenchyma. This is different from the conventional concept of hypo perfusion of the involved brain in CTP performed in the “post-ictal” phase. The interpreting radiologist should be informed about the patient symptoms and should avoid solo visual assessment of CT perfusion in patients under the “stroke code”.
    Keywords: CT Perfusion, Stroke, Seizure, Status Epilepticus
  • Manijeh Alavi , Ameneh Setareh Forouzan , Homeira Sajjadi , Mohammad Reza Khodaie Ardakani , Mohsen Shati , Maziar Moradi, Lakeh * Page 20
     
    Background
    Nowadays, change in the pattern of diseases to chronic has been with increasing use of medical imaging services. People with physical disability require continuous diagnostic and therapeutic services.
    Objectives
    This study aimed to measure the waiting time for receiving medical imaging services and to examine sociodemographic factors associated with the poor experience of these people. Patients and
    Methods
    In a cross-sectional study to assess the responsiveness of comprehensive rehabilitation centers in Tehran in 2016 - 2017, 610 people with physical disabilities who were referred to 10 comprehensive physical rehabilitation centers for rehabilitation services were asked whether they had used medical imaging services during their rehabilitation. The 477 participants (218 women) with positive response consisted the sample of this study. A checklist was used for data collection. T test, Chi-Square and Multiple Logistic Regression Model were used for analytical reports.
    Results
    Poor experience in prompt attention of centers was reported by 26% of public diagnostic service users while 16% of private sector users and 21.2% by total sample. Waiting time for appointment and waiting time at the center were significantly longer in public medical imaging centers compared to the private sector (P < 0.05). Overall experience of public service users about prompt attention was poorer than the private sector (P < 0.05). Physical status (odd ratio [OR] = 3.2; 95% confidence interval [CI] = 1.3 - 7.8) and duration of disability (OR = 0.28; 95% CI = 0.09 - 0.9) were the predictors of poor experience of respondents about prompt attention in public and private centers respectively.
    Conclusion
    From the service users’ viewpoint, private centers had better performance in prompt attention than public centers. Attention to physical condition and duration of disability in scheduling diagnostic services is recommended.
    Keywords: Prompt Attention, Diagnostic Medical Imaging Centers, Physical Disability, Tehran