BioMed Research International: Radiology The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. GRE T2-Weighted MRI: Principles and Clinical Applications Wed, 16 Apr 2014 13:39:56 +0000 The sequence of a multiecho gradient recalled echo (GRE) T2-weighted imaging (T2WI) is a relatively new magnetic resonance imaging (MRI) technique. In contrast to T2 relaxation, which acquires a spin echo signal, T2 relaxation acquires a gradient echo signal. The sequence of a GRE T2WI requires high uniformity of the magnetic field. GRE T2WI can detect the smallest changes in uniformity in the magnetic field and can improve the rate of small lesion detection. In addition, the T2 value can indirectly reflect changes in tissue biochemical components. Moreover, it can be used for the early diagnosis and quantitative diagnosis of some diseases. This paper reviews the principles and clinical applications as well as the advantages and disadvantages of GRE T2WI. Meng Yue Tang, Tian Wu Chen, Xiao Ming Zhang, and Xiao Hua Huang Copyright © 2014 Meng Yue Tang et al. All rights reserved. The Role of Imaging in Radiation Therapy Planning: Past, Present, and Future Thu, 10 Apr 2014 06:44:02 +0000 The use of ionizing radiation for cancer treatment has undergone extraordinary development during the past hundred years. The advancement of medical imaging has been critical in helping to achieve this change. The invention of computed tomography (CT) was pivotal in the development of treatment planning. Despite some disadvantages, CT remains the only three-dimensional imaging modality used for dose calculation. Newer image modalities, such as magnetic resonance (MR) imaging and positron emission tomography (PET), are also used secondarily in the treatment-planning process. MR, with its better tissue contrast and resolution than those of CT, improves tumor definition compared with CT planning alone. PET also provides metabolic information to supplement the CT and MR anatomical information. With emerging molecular imaging techniques, the ability to visualize and characterize tumors with regard to their metabolic profile, active pathways, and genetic markers, both across different tumors and within individual, heterogeneous tumors, will inform clinicians regarding the treatment options most likely to benefit a patient and to detect at the earliest time possible if and where a chosen therapy is working. In the post-human-genome era, multimodality scanners such as PET/CT and PET/MR will provide optimal tumor targeting information. Gisele C. Pereira, Melanie Traughber, and Raymond F. Muzic Jr. Copyright © 2014 Gisele C. Pereira et al. All rights reserved. Rational Design of a Triple Reporter Gene for Multimodality Molecular Imaging Mon, 07 Apr 2014 12:31:51 +0000 Multimodality imaging using noncytotoxic triple fusion (TF) reporter genes is an important application for cell-based tracking, drug screening, and therapy. The firefly luciferase (fl), monomeric red fluorescence protein (mrfp), and truncated herpes simplex virus type 1 thymidine kinase SR39 mutant (ttksr39) were fused together to create TF reporter gene constructs with different order. The enzymatic activities of TF protein in vitro and in vivo were determined by luciferase reporter assay, -FEAU cellular uptake experiment, bioluminescence imaging, and micropositron emission tomography (microPET). The TF construct expressed in H1299 cells possesses luciferase activity and red fluorescence. The tTKSR39 activity is preserved in TF protein and mediates high levels of -FEAU accumulation and significant cell death from ganciclovir (GCV) prodrug activation. In living animals, the luciferase and tTKSR39 activities of TF protein have also been successfully validated by multimodality imaging systems. The red fluorescence signal is relatively weak for in vivo imaging but may expedite FACS-based selection of TF reporter expressing cells. We have developed an optimized triple fusion reporter construct DsRedm-fl-ttksr39 for more effective and sensitive in vivo animal imaging using fluorescence, bioluminescence, and PET imaging modalities, which may facilitate different fields of biomedical research and applications. Ya-Ju Hsieh, Luen Hwu, Chien-Chih Ke, Skye Hsin-Hsien Yeh, Chien-Feng Lin, Fu-Du Chen, Hsin-Ell Wang, Kang-Ping Lin, Ran-Chou Chen, and Ren-Shyan Liu Copyright © 2014 Ya-Ju Hsieh et al. All rights reserved. Acute Ethanol-Induced Changes in Edema and Metabolite Concentrations in Rat Brain Tue, 25 Mar 2014 09:10:25 +0000 The aim of this study is to describe the acute effects of EtOH on brain edema and cerebral metabolites, using diffusion weight imaging (DWI) and proton magnetic resonance spectroscopy (1H-MRS) at a 7.0T MR and to define changes in apparent diffusion coefficient (ADC) values and the concentration of metabolites in the rat brain after acute EtOH intoxication. ADC values in each ROI decreased significantly at 1 h and 3 h after ethanol administration. ADC values in frontal lobe were decreased significantly compared with other regions at 3 h. For EtOH/Cr+PCr and cerebral metabolites (Cho, Tau, and Glu) differing over time, no significant differences for Ins, NAA, and Cr were observed in frontal lobes. Regression analysis revealed a significant association between TSEtOH/Cr+PCr and TSCho, TSTau, TSGlu, and TSADC. The changes of ADC values in different brain regions reflect the process of the cytotoxic edema in vivo. The characterization of frontal lobes metabolites changes and the correlations between TSEtOH/Cr+PCr and TSCho, TSTau, and TSGlu provide a better understanding for the biological mechanisms in neurotoxic effects of EtOH on the brain. In addition, the correlations between TSEtOH/Cr+PCr and TSADC will help us to understand development of the ethanol-induced brain cytotoxic edema. Huimin Liu, Wenbin Zheng, Gen Yan, Baoguo Liu, Lingmei Kong, Yan Ding, Zhiwei Shen, Hui Tan, and Guishan Zhang Copyright © 2014 Huimin Liu et al. All rights reserved. Development and Evaluation of an Open-Source Software Package “CGITA” for Quantifying Tumor Heterogeneity with Molecular Images Mon, 17 Mar 2014 08:18:09 +0000 Background. The quantification of tumor heterogeneity with molecular images, by analyzing the local or global variation in the spatial arrangements of pixel intensity with texture analysis, possesses a great clinical potential for treatment planning and prognosis. To address the lack of available software for computing the tumor heterogeneity on the public domain, we develop a software package, namely, Chang-Gung Image Texture Analysis (CGITA) toolbox, and provide it to the research community as a free, open-source project. Methods. With a user-friendly graphical interface, CGITA provides users with an easy way to compute more than seventy heterogeneity indices. To test and demonstrate the usefulness of CGITA, we used a small cohort of eighteen locally advanced oral cavity (ORC) cancer patients treated with definitive radiotherapies. Results. In our case study of ORC data, we found that more than ten of the current implemented heterogeneity indices outperformed SUVmean for outcome prediction in the ROC analysis with a higher area under curve (AUC). Heterogeneity indices provide a better area under the curve up to 0.9 than the SUVmean and TLG (0.6 and 0.52, resp.). Conclusions. CGITA is a free and open-source software package to quantify tumor heterogeneity from molecular images. CGITA is available for free for academic use at Yu-Hua Dean Fang, Chien-Yu Lin, Meng-Jung Shih, Hung-Ming Wang, Tsung-Ying Ho, Chun-Ta Liao, and Tzu-Chen Yen Copyright © 2014 Yu-Hua Dean Fang et al. All rights reserved. Pushing CT and MR Imaging to the Molecular Level for Studying the “Omics”: Current Challenges and Advancements Thu, 13 Mar 2014 09:48:00 +0000 During the past decade, medical imaging has made the transition from anatomical imaging to functional and even molecular imaging. Such transition provides a great opportunity to begin the integration of imaging data and various levels of biological data. In particular, the integration of imaging data and multiomics data such as genomics, metabolomics, proteomics, and pharmacogenomics may open new avenues for predictive, preventive, and personalized medicine. However, to promote imaging-omics integration, the practical challenge of imaging techniques should be addressed. In this paper, we describe key challenges in two imaging techniques: computed tomography (CT) and magnetic resonance imaging (MRI) and then review existing technological advancements. Despite the fact that CT and MRI have different principles of image formation, both imaging techniques can provide high-resolution anatomical images while playing a more and more important role in providing molecular information. Such imaging techniques that enable single modality to image both the detailed anatomy and function of tissues and organs of the body will be beneficial in the imaging-omics field. Hsuan-Ming Huang and Yi-Yu Shih Copyright © 2014 Hsuan-Ming Huang and Yi-Yu Shih. All rights reserved. Automatic Detection and Quantification of Acute Cerebral Infarct by Fuzzy Clustering and Histographic Characterization on Diffusion Weighted MR Imaging and Apparent Diffusion Coefficient Map Wed, 12 Mar 2014 16:58:04 +0000 Determination of the volumes of acute cerebral infarct in the magnetic resonance imaging harbors prognostic values. However, semiautomatic method of segmentation is time-consuming and with high interrater variability. Using diffusion weighted imaging and apparent diffusion coefficient map from patients with acute infarction in 10 days, we aimed to develop a fully automatic algorithm to measure infarct volume. It includes an unsupervised classification with fuzzy C-means clustering determination of the histographic distribution, defining self-adjusted intensity thresholds. The proposed method attained high agreement with the semiautomatic method, with similarity index 89.9 ± 6.5%, in detecting cerebral infarct lesions from 22 acute stroke patients. We demonstrated the accuracy of the proposed computer-assisted prompt segmentation method, which appeared promising to replace the laborious, time-consuming, and operator-dependent semiautomatic segmentation. Jang-Zern Tsai, Syu-Jyun Peng, Yu-Wei Chen, Kuo-Wei Wang, Hsiao-Kuang Wu, Yun-Yu Lin, Ying-Ying Lee, Chi-Jen Chen, Huey-Juan Lin, Eric Edward Smith, Poh-Shiow Yeh, and Yue-Loong Hsin Copyright © 2014 Jang-Zern Tsai et al. All rights reserved. Current Opportunities and Challenges of Magnetic Resonance Spectroscopy, Positron Emission Tomography, and Mass Spectrometry Imaging for Mapping Cancer Metabolism In Vivo Mon, 03 Mar 2014 00:00:00 +0000 Cancer is known to have unique metabolic features such as Warburg effect. Current cancer therapy has moved forward from cytotoxic treatment to personalized, targeted therapies, with some that could lead to specific metabolic changes, potentially monitored by imaging methods. In this paper we addressed the important aspects to study cancer metabolism by using image techniques, focusing on opportunities and challenges of magnetic resonance spectroscopy (MRS), dynamic nuclear polarization (DNP)-MRS, positron emission tomography (PET), and mass spectrometry imaging (MSI) for mapping cancer metabolism. Finally, we highlighted the future possibilities of an integrated in vivo PET/MR imaging systems, together with an in situ MSI tissue analytical platform, may become the ultimate technologies for unraveling and understanding the molecular complexities in some aspects of cancer metabolism. Such comprehensive imaging investigations might provide information on pharmacometabolomics, biomarker discovery, and disease diagnosis, prognosis, and treatment response monitoring for clinical medicine. Gigin Lin and Yuen-Li Chung Copyright © 2014 Gigin Lin and Yuen-Li Chung. All rights reserved. Establishment of a Swine Model for Validation of Perfusion Measurement by Dynamic Contrast-Enhanced Magnetic Resonance Imaging Thu, 27 Feb 2014 06:39:47 +0000 The aim of the study was to develop a suitable animal model for validating dynamic contrast-enhanced magnetic resonance imaging perfusion measurements. A total of 8 pigs were investigated by DCE-MRI. Perfusion was determined on the hind leg musculature. An ultrasound flow probe placed around the femoral artery provided flow measurements independent of MRI and served as the standard of reference. Images were acquired on a 1.5 T MRI scanner using a 3D T1-weighted gradient-echo sequence. An arterial catheter for local injection was implanted in the femoral artery. Continuous injection of adenosine for vasodilation resulted in steady blood flow levels up to four times the baseline level. In this way, three different stable perfusion levels were induced and measured. A central venous catheter was used for injection of two different types of contrast media. A low-molecular weight contrast medium and a blood pool contrast medium were used. A total of 6 perfusion measurements were performed with a time interval of about 20–25 min without significant differences in the arterial input functions. In conclusion the accuracy of DCE-MRI-based perfusion measurement can be validated by comparison of the integrated perfusion signal of the hind leg musculature with the blood flow values measured with the ultrasound flow probe around the femoral artery. Anika Sauerbrey, Stefan Hindel, Marc Maaß, Christine Krüger, Andreas Wissmann, Martin Kramer, Benno Nafz, and Lutz Lüdemann Copyright © 2014 Anika Sauerbrey et al. All rights reserved. Performance Enhancement of a Web-Based Picture Archiving and Communication System Using Commercial Off-the-Shelf Server Clusters Thu, 20 Feb 2014 16:42:29 +0000 The rapid development of picture archiving and communication systems (PACSs) thoroughly changes the way of medical informatics communication and management. However, as the scale of a hospital’s operations increases, the large amount of digital images transferred in the network inevitably decreases system efficiency. In this study, a server cluster consisting of two server nodes was constructed. Network load balancing (NLB), distributed file system (DFS), and structured query language (SQL) duplication services were installed. A total of 1 to 16 workstations were used to transfer computed radiography (CR), computed tomography (CT), and magnetic resonance (MR) images simultaneously to simulate the clinical situation. The average transmission rate (ATR) was analyzed between the cluster and noncluster servers. In the download scenario, the ATRs of CR, CT, and MR images increased by 44.3%, 56.6%, and 100.9%, respectively, when using the server cluster, whereas the ATRs increased by 23.0%, 39.2%, and 24.9% in the upload scenario. In the mix scenario, the transmission performance increased by 45.2% when using eight computer units. The fault tolerance mechanisms of the server cluster maintained the system availability and image integrity. The server cluster can improve the transmission efficiency while maintaining high reliability and continuous availability in a healthcare environment. Yan-Lin Liu, Cheng-Ting Shih, Yuan-Jen Chang, Shu-Jun Chang, and Jay Wu Copyright © 2014 Yan-Lin Liu et al. All rights reserved. Respiratory-Gated MRgHIFU in Upper Abdomen Using an MR-Compatible In-Bore Digital Camera Wed, 29 Jan 2014 13:31:41 +0000 Objective. To demonstrate the technical feasibility and the potential interest of using a digital optical camera inside the MR magnet bore for monitoring the breathing cycle and subsequently gating the PRFS MR thermometry, MR-ARFI measurement, and MRgHIFU sonication in the upper abdomen. Materials and Methods. A digital camera was reengineered to remove its magnetic parts and was further equipped with a 7 m long USB cable. The system was electromagnetically shielded and operated inside the bore of a closed 3T clinical scanner. Suitable triggers were generated based on real-time motion analysis of the images produced by the camera (resolution pixels, 30 fps). Respiratory-gated MR-ARFI prepared MRgHIFU ablation was performed in the kidney and liver of two sheep in vivo, under general anaesthesia and ventilator-driven forced breathing. Results. The optical device demonstrated very good MR compatibility. The current setup permitted the acquisition of motion artefact-free and high resolution MR 2D ARFI and multiplanar interleaved PRFS thermometry (average SNR 30 in liver and 56 in kidney). Microscopic histology indicated precise focal lesions with sharply delineated margins following the respiratory-gated HIFU sonications. Conclusion. The proof-of-concept for respiratory motion management in MRgHIFU using an in-bore digital camera has been validated in vivo. Vincent Auboiroux, Lorena Petrusca, Magalie Viallon, Arnaud Muller, Sylvain Terraz, Romain Breguet, Xavier Montet, Christoph D. Becker, and Rares Salomir Copyright © 2014 Vincent Auboiroux et al. All rights reserved. Differential Regulation of Ferritin Subunits and Iron Transport Proteins: An Effect of Targeted Hepatic X-Irradiation Thu, 12 Dec 2013 08:57:05 +0000 The current study aimed to investigate radiation-induced regulation of iron proteins including ferritin subunits in rats. Rat livers were selectively irradiated in vivo at 25 Gy. This dose can be used to model radiation effects to the liver without inducing overt radiation-induced liver disease. Sham-irradiated rats served as controls. Isolated hepatocytes were irradiated at 8 Gy. Ferritin light polypeptide (FTL) was detectable in the serum of sham-irradiated rats with an increase after irradiation. Liver irradiation increased hepatic protein expression of both ferritin subunits. A rather early increase (3 h) was observed for hepatic TfR1 and Fpn-1 followed by a decrease at 12 h. The increase in TfR2 persisted over the observed time. Parallel to the elevation of AST levels, a significant increase (24 h) in hepatic iron content was measured. Complete blood count analysis showed a significant decrease in leukocyte number with an early increase in neutrophil granulocytes and a decrease in lymphocytes. In vitro, a significant increase in ferritin subunits at mRNA level was detected after irradiation which was further induced with a combination treatment of irradiation and acute phase cytokine. Irradiation can directly alter the expression of ferritin subunits and this response can be strongly influenced by radiation-induced proinflammatory cytokines. FTL can be used as a serum marker for early phase radiation-induced liver damage. Naila Naz, Shakil Ahmad, Silke Cameron, Federico Moriconi, Margret Rave-Fränk, Hans Christiansen, Clemens Friedrich Hess, Giuliano Ramadori, and Ihtzaz A. Malik Copyright © 2013 Naila Naz et al. All rights reserved. The Importance and Perspective of Magnetic Resonance Imaging in the Evaluation of Endometriosis Wed, 20 Nov 2013 15:00:32 +0000 MR imaging is becoming increasingly important in the assessment of patients with endometriosis. Its multiplanar capabilities and superior soft tissue contrast are particularly useful in the detection of deep infiltrating endometriotic implants. Endometriosis, defined as the presence of endometrial glands and stroma outside the endometrium, is among the most common gynaecological disorders affecting women in their reproductive age. The diagnosis and evaluation of the extension of endometriosis are difficult only with physical examination and laparoscopy. According to the authors’ personal experience, a special MRI technique and some imaging guidelines regarding different anatomical localizations of endometriosis are discussed. This review is a brief presentation of current evidence on the diagnostic accuracy of MRI in the evaluation of endometriosis concerning other diagnostic methods, the limitations of MRI and its essential usefulness for preoperative diagnosis of deep pelvic endometriosis, and future perspectives in monitoring this disease. Agnieszka Bianek-Bodzak, Edyta Szurowska, Sambor Sawicki, and Marcin Liro Copyright © 2013 Agnieszka Bianek-Bodzak et al. All rights reserved. Cone Beam Computed Tomographic Analysis of the Shape, Height, and Location of the Mandibular Lingula in a Population of Children Wed, 20 Nov 2013 15:00:28 +0000  Objectives. This is the first study to identify and classify the different morphological shapes of the mandibular lingula (ML) in children using cone-beam computed tomography (CBCT). Material and Methods. A retrospective study was performed to evaluate the shape, height, and location of the ML in relation to the surrounding structures using CBCT images of mandibles obtained from 269 children. The shape of the ML was classified into triangular, truncated, nodular, or assimilated types. The location was determined by five distances. The height of the lingula was also measured from the lingular tip to the mandibular foramen. Results. A nodular shape of the ML was most commonly found (48.3%, ) followed by truncated (23.4%, ), assimilated (14.4%, ), and triangular (13.7%, ). The mean distance of ML from the anterior and posterior borders of mandibular ramus was  mm and  mm, respectively. In the majority of the mandibles studied, the ML was located above the occlusal plane. Conclusion. The present study provides new information to the literature concerning the shape, height, and location of the lingula in a Turkish pediatric population. This finding may assist clinicians to localize the lingula and avoid intraoperative complications. Ahmet Ercan Sekerci, Kenan Cantekin, and Mustafa Aydinbelge Copyright © 2013 Ahmet Ercan Sekerci et al. All rights reserved. Similar-Case-Based Optimization of Beam Arrangements in Stereotactic Body Radiotherapy for Assisting Treatment Planners Sat, 02 Nov 2013 14:30:18 +0000 Objective. To develop a similar-case-based optimization method for beam arrangements in lung stereotactic body radiotherapy (SBRT) to assist treatment planners. Methods. First, cases that are similar to an objective case were automatically selected based on geometrical features related to a planning target volume (PTV) location, PTV shape, lung size, and spinal cord position. Second, initial beam arrangements were determined by registration of similar cases with the objective case using a linear registration technique. Finally, beam directions of the objective case were locally optimized based on the cost function, which takes into account the radiation absorption in normal tissues and organs at risk. The proposed method was evaluated with 10 test cases and a treatment planning database including 81 cases, by using 11 planning evaluation indices such as tumor control probability and normal tissue complication probability (NTCP). Results. The procedure for the local optimization of beam arrangements improved the quality of treatment plans with significant differences () in the homogeneity index and conformity index for the PTV, V10, V20, mean dose, and NTCP for the lung. Conclusion. The proposed method could be usable as a computer-aided treatment planning tool for the determination of beam arrangements in SBRT. Taiki Magome, Hidetaka Arimura, Yoshiyuki Shioyama, Katsumasa Nakamura, Hiroshi Honda, and Hideki Hirata Copyright © 2013 Taiki Magome et al. All rights reserved. Effect of Alcohol on Diffuse Axonal Injury in Rat Brainstem: Diffusion Tensor Imaging and Aquaporin-4 Expression Study Sun, 27 Oct 2013 11:10:27 +0000 The aim of this study is to assess the effects of alcohol on traumatic brain injury by using diffusion tensor imaging (DTI) and evaluate aquaporin-4(AQP4) expression changes in rat brainstems following acute alcohol intoxication with diffuse axonal injury (DAI). We further investigated the correlation between the AQP4 expression and DTI in the brain edema. Eighty-five rats were imaged before and after injury at various stages. DTI was used to measure brainstem apparent diffusion coefficient (ADC) and fractional anisotropy (FA), with immunostaining being used to determine AQP4 expression. After acute alcoholism with DAI, ADC values of the brainstem first decreased within 6 h and then elevated. FA values began to decline by 1 h, reaching a minimum at 24 h after trauma. There was a negative correlation between ADC values and brainstem AQP4 expression at 6 h and positive correlation at 6 h to 24 h. Changes of ADC and FA values in DAI with acute alcoholism indicate the effects of ethanol on brain edema and the severity of axonal injury. The correlations between ADC values and the brainstem AQP4 expression at different time points suggest that AQP4 expression follows an adaptative profile to the severity of brain edema. Lingmei Kong, Gengpeng Lian, Wenbin Zheng, Huimin Liu, Haidu Zhang, and Ruowei Chen Copyright © 2013 Lingmei Kong et al. All rights reserved. Design and Validation of an Augmented Reality System for Laparoscopic Surgery in a Real Environment Wed, 23 Oct 2013 09:09:42 +0000 Purpose. This work presents the protocol carried out in the development and validation of an augmented reality system which was installed in an operating theatre to help surgeons with trocar placement during laparoscopic surgery. The purpose of this validation is to demonstrate the improvements that this system can provide to the field of medicine, particularly surgery. Method. Two experiments that were noninvasive for both the patient and the surgeon were designed. In one of these experiments the augmented reality system was used, the other one was the control experiment, and the system was not used. The type of operation selected for all cases was a cholecystectomy due to the low degree of complexity and complications before, during, and after the surgery. The technique used in the placement of trocars was the French technique, but the results can be extrapolated to any other technique and operation. Results and Conclusion. Four clinicians and ninety-six measurements obtained of twenty-four patients (randomly assigned in each experiment) were involved in these experiments. The final results show an improvement in accuracy and variability of 33% and 63%, respectively, in comparison to traditional methods, demonstrating that the use of an augmented reality system offers advantages for trocar placement in laparoscopic surgery. F. López-Mir, V. Naranjo, J. J. Fuertes, M. Alcañiz, J. Bueno, and E. Pareja Copyright © 2013 F. López-Mir et al. All rights reserved. Glutamine/Glutamate Metabolism Studied with Magnetic Resonance Spectroscopic Imaging for the Characterization of Adrenal Nodules and Masses Wed, 02 Oct 2013 17:53:36 +0000 Purpose. To assess glutamine/glutamate (Glx) and lactate (Lac) metabolism using proton magnetic resonance spectroscopic imaging (1H-MRS) in order to differentiate between adrenal gland nodules and masses (adenomas, pheochromocytomas, carcinomas, and metastases). Materials and Methods. Institutional review board approval and informed consent were obtained. A total of 130 patients (47 men) with 132 adrenal nodules/masses were prospectively assessed ( years). A multivoxel system was used with a two-dimensional point-resolved spectroscopy/chemical-shift imaging sequence. Spectroscopic data were interpreted by visual inspection and peak amplitudes of lipids (Lip), choline (Cho), creatine (Cr), Lac, and Glx. Lac/Cr and Glx/Cr were calculated. Glx/Cr was assessed in relation to lesion size. Results. Statistically significant differences were observed in Glx/Cr results between adenomas and pheochromocytomas (), however, with a low positive predictive value (PPV). Glx levels were directly proportional to lesion size in carcinomas. A cutoff point of 1.44 was established for the differentiation between carcinomas larger versus smaller than 4 cm, with 75% sensitivity, 100% specificity, 100% PPV, and 80% accuracy. Lac/Cr results showed no differences across lesions. A cutoff point of −6.5 for Lac/Cr was established for carcinoma diagnosis. Conclusion. Glx levels are directly proportional to lesion size in carcinomas. A cutoff point of −6.5 Lac/Cr differentiates carcinomas from noncarcinomas. Suzan M. Goldman, Thiago F. Nunes, Homero J. F. Melo, Claudio Dalavia, Denis Szejnfeld, Claudio Kater, Cassio Andreoni, Jacob Szejnfeld, and Sergio A. Ajzen Copyright © 2013 Suzan M. Goldman et al. All rights reserved. Risk Management in Magnetic Resonance: Failure Mode, Effects, and Criticality Analysis Thu, 19 Sep 2013 08:26:32 +0000 The aim of the study was to perform a risk management procedure in “Magnetic Resonance Examination” process in order to identify the critical phases and sources of radiological errors and to identify potential improvement projects including procedures, tests, and checks to reduce the error occurrence risk. In this study we used the proactive analysis “Failure Mode Effects Criticality Analysis,” a qualitative and quantitative risk management procedure; has calculated Priority Risk Index (PRI) for each activity of the process; have identified, on the PRI basis, the most critical activities and, for them, have defined improvement projects; and have recalculated the PRI after implementation of improvement projects for each activity. Time stop and audits are performed in order to control the new procedures. The results showed that the most critical tasks of “Magnetic Resonance Examination” process were the reception of the patient, the patient schedule drafting, the closing examination, and the organization of activities. Four improvement projects have been defined and executed. PRI evaluation after improvement projects implementation has shown that the risk decreased significantly following the implementation of procedures and controls defined in improvement projects, resulting in a reduction of the PRI between 43% and 100%. Antonella Petrillo, Roberta Fusco, Vincenza Granata, Salvatore Filice, Nicola Raiano, Daniela Maria Amato, Maria Zirpoli, Alessandro di Finizio, Mario Sansone, Anna Russo, Eugenio Maria Covelli, Tonino Pedicini, and Maria Triassi Copyright © 2013 Antonella Petrillo et al. All rights reserved. Estimation of the Lateral Ventricles Volumes from a 2D Image and Its Relationship with Cerebrospinal Fluid Flow Mon, 16 Sep 2013 13:35:16 +0000 Purpose. This work suggests a fast estimation method of the lateral ventricles volume from a 2D image and then determines if this volume is correlated with the cerebrospinal fluid flow at the aqueductal and cerebral levels in neurodegenerative diseases. Materials and Methods. FForty-five elderly patients suffering from Alzheimer’s disease (19), normal pressure hydrocephalus (13), and vascular dementia (13) were involved and underwent anatomical and phase contrast MRI scans. Lateral ventricles and stroke volumes were assessed on anatomical and phase contrast scans, respectively. A common reference plane was used to calculate the lateral ventricles’ area on 2D images. Results. The largest volumes were observed in hydrocephalus patients. The linear regression between volumes and areas was computed, and a strong positive correlation was detected (). A derived equation was determined to represent the volumes for any given area. On the other hand, no significant correlations were detected between ventricles and stroke volumes (). Conclusion. Lateral ventricles volumes are significantly proportional to the 2D reference section area and could be used for patients’ follow-up even if 3D images are unavailable. The cerebrospinal fluid fluctuations in brain disorders may depend on many physiological parameters other than the ventricular morphology. Chaarani Bader, Capel Cyrille, Zmudka Jadwiga, Daouk Joel, Anthony Fichten, Gondry-Jouet Catherine, Bouzerar Roger, and Balédent Olivier Copyright © 2013 Chaarani Bader et al. All rights reserved. Postmortem Computed Tomography Imaging in the Investigation of Nontraumatic Death in Infants and Children Wed, 04 Sep 2013 13:31:05 +0000 Objective. To determine the accuracy of postmortem computed tomography (PMCT) for the assessment of causes in nontraumatic deaths in children. Study Design. We enrolled cases of nontraumatic deaths of infants and children who underwent PMCT at a single center. The presumed cause of death determined by PMCT was prospectively compared with the clinical and pathological diagnoses of deaths. Results. Thirty-eight cases were enrolled for analysis. Among them, seven cases also underwent conventional medical autopsy. PMCT revealed an identifiable cause of death in accordance with the clinical diagnosis of death in 16 cases of the 38 cases (the concordance rate was 42%) and in accordance with the autopsy cause of death in four of the seven autopsy cases (the concordance rate was 57%). Among eight cases with unknown cause of death by clinical diagnosis, four cases (50%) were identified with cardiac tamponade as a cause of death (one case) and intracranial hemorrhage suggesting abuse (3 cases). Conclusions. PMCT seems to be a promising technique that might serve as a substitute for conventional medical autopsy and give us the complementary information to clinical diagnoses particularly in cases of child abuse. Larger multicenter trials are worthwhile to validate the general feasibility of PMCT. Yukihiro Noda, Ken Yoshimura, Shoji Tsuji, Atsushi Ohashi, Hirohide Kawasaki, Kazunari Kaneko, Shigeki Ikeda, Hiroaki Kurokawa, and Noboru Tanigawa Copyright © 2013 Yukihiro Noda et al. All rights reserved. Congenital and Acquired Abnormalities of the Corpus Callosum: A Pictorial Essay Tue, 06 Aug 2013 09:17:49 +0000 The purpose of this review is to illustrate the wide spectrum of lesions in the corpus callosum, both congenital and acquired: developmental abnormalities, phakomatoses, neurometabolic disorders, demyelinating diseases, infection and inflammation, vascular lesions, neoplasms, traumatic and iatrogenic injury, and others. Cases include fetuses, children, and adults with rich iconography from the authors’ own archive. Katarzyna Krupa and Monika Bekiesinska-Figatowska Copyright © 2013 Katarzyna Krupa and Monika Bekiesinska-Figatowska. All rights reserved. Qualitative and Quantitative Hippocampal MRI Assessments in Intractable Epilepsy Mon, 29 Jul 2013 08:32:39 +0000 Aims. To acquire normative data of hippocampal volumes and T2 relaxation times, to evaluate and compare qualitative and quantitative assessments in evaluating hippocampi in patients with different durations of intractable epilepsy, and to propose an imaging protocol based on performance of these techniques. Methods. MRI analysis was done in 50 nonepileptic controls and 30 patients with intractable epilepsy on 1.5T scanner. Visual assessment and hippocampal volumetry were done on oblique coronal IR/T2W and T1W MP-RAGE images, respectively. T2 relaxation times were measured using 16-echo Carr-Purcell-Meiboom-Gill sequence. Volumetric data was normalized for variation in head size between individuals. Patients were divided into temporal () and extratemporal () groups based on clinical and EEG localization. Results. In controls, right hippocampal volume was slightly more than the left with no effect of age or gender. In TLE patients, hippocampal volumetry provided maximum concordance with EEG. Visual assessment of unilateral pathology concurred well with measured quantitative values but poorly in cases with bilateral pathologies. There were no significant differences of mean values between extratemporal group and controls group. Quantitative techniques detected mild abnormalities, undetected on visual assessment. Conclusions. Quantitative techniques are more sensitive to diagnose bilateral and mild unilateral hippocampal abnormalities. Paramdeep Singh, Rupinderjeet Kaur, Kavita Saggar, Gagandeep Singh, and Amarpreet Kaur Copyright © 2013 Paramdeep Singh et al. All rights reserved. Magnetic Resonance Sialography Findings of Submandibular Ducts Imaging Thu, 25 Jul 2013 10:13:38 +0000 Purpose. We aimed to assess the problem solving capability of magnetic resonance sialography (MR sialography), a noninvasive method for imaging submandibular gland ducts and determining duct-related pathologies, by comparing diseased and healthy cases. Materials and Methods. We conducted radiological assessment on a total of 60 submandibular glands (mean age 44.7) in 20 cases and 10 volunteers. MR sialography examinations were conducted with single-shot fast spin-echo sequence by using a surface coil placed on the submandibular gland. Each gland was evaluated in terms of the length, width and stricture of the main duct, as well as the difference between the intraparenchymal duct width, and the main duct width. Statistical analysis was performed. Results. In the MR sialography the primary duct mean length was determined as 51 mm (40–57 mm) in all submandibular glands. On the MR sialography imaging, the visualization ratio of the ductal system of submandibular gland was evaluated in the cases and volunteers. Conclusion. MR sialography is an effective and a noninvasive method in imaging submandibular gland ducts, demonstrating the presence, location and degree of stricture/dilatation, and elucidating the disease etiology. Nezahat Karaca Erdoğan, Canan Altay, Nesibe Özenler, Tuğba Bozkurt, Engin Uluç, Berna Dirim Mete, and İsmail Özdemir Copyright © 2013 Nezahat Karaca Erdoğan et al. All rights reserved. Assessment of Hemodynamics in a Rat Model of Liver Cirrhosis with Precancerous Lesions Using Multislice Spiral CT Perfusion Imaging Thu, 20 Jun 2013 13:26:39 +0000 Rationale and Objectives. To develop an optimal scanning protocol for multislice spiral CT perfusion (CTP) imaging to evaluate hemodynamic changes in liver cirrhosis with diethylnitrosamine- (DEN-) induced precancerous lesions. Materials and Methods. Male Wistar rats were randomly divided into the control group () and the precancerous liver cirrhosis group (). The control group received saline injection and the liver cirrhosis group received 50 mg/kg DEN i.p. twice a week for 12 weeks. All animals underwent plain CT scanning, CTP, and contrast-enhanced CT scanning. Scanning parameters were optimized by adjusting the diatrizoate concentration, the flow rate, and the delivery time. The hemodynamics of both groups was further compared using optimized multislice spiral CTP imaging. Results. High-quality CTP images were obtained with following parameters: 150 kV; 150 mAs; 5 mm thickness, 5 mm interval; pitch, 1; matrix, ; and FOV, 9.6 cm. Compared to the control group, the liver cirrhosis group had a significantly increased value of the hepatic arterial fraction and the hepatic artery perfusion () but significantly decreased hepatic portal perfusion and mean transit time (). Conclusion. Multislice spiral CTP imaging can be used to evaluate the hemodynamic changes in the rat model of liver cirrhosis with precancerous lesions. Guolin Ma, Rongjie Bai, Huijie Jiang, Xuejia Hao, Zaisheng Ling, and Kefeng Li Copyright © 2013 Guolin Ma et al. All rights reserved. Simultaneous Reduction in Noise and Cross-Contamination Artifacts for Dual-Energy X-Ray CT Wed, 19 Jun 2013 11:34:58 +0000 Purpose. Dual-energy CT imaging tends to suffer from much lower signal-to-noise ratio than single-energy CT. In this paper, we propose an improved anticorrelated noise reduction (ACNR) method without causing cross-contamination artifacts. Methods. The proposed algorithm diffuses both basis material density images (e.g., water and iodine) at the same time using a novel correlated diffusion algorithm. The algorithm has been compared to the original ACNR algorithm in a contrast-enhanced, IRB-approved patient study. Material density accuracy and noise reduction are quantitatively evaluated by the percent density error and the percent noise reduction. Results. Both algorithms have significantly reduced the noises of basis material density images in all cases. The average percent noise reduction is 69.3% and 66.5% with the ACNR algorithm and the proposed algorithm, respectively. However, the ACNR algorithm alters the original material density by an average of 13% (or 2.18 mg/cc) with a maximum of 58.7% (or 8.97 mg/cc) in this study. This is evident in the water density images as massive cross-contaminations are seen in all five clinical cases. On the contrary, the proposed algorithm only changes the mean density by 2.4% (or 0.69 mg/cc) with a maximum of 7.6% (or 1.31 mg/cc). The cross-contamination artifacts are significantly minimized or absent with the proposed algorithm. Conclusion. The proposed algorithm can significantly reduce image noise present in basis material density images from dual-energy CT imaging, with minimized cross-contaminations compared to the ACNR algorithm. Baojun Li, Baohong Li, Jack Luo, Peng Tang, Jiandong Mao, and Xiaoye Wu Copyright © 2013 Baojun Li et al. All rights reserved. Improvements in the Quantitative Assessment of Cerebral Blood Volume and Flow with the Removal of Vessel Voxels from MR Perfusion Images Mon, 18 Mar 2013 09:48:00 +0000 Objective. To improve the quantitative assessment of cerebral blood volume (CBV) and flow (CBF) in the brain voxels from MR perfusion images. Materials and Methods. Normal brain parenchyma was automatically segmented with the time-to-peak criteria after cerebrospinal fluid removal and preliminary vessel voxel removal. Two scaling factors were calculated by comparing the relative CBV and CBF of the segmented normal brain parenchyma with the absolute values in the literature. Using the scaling factors, the relative values were converted to the absolute CBV and CBF. Voxels with either CBV > 8 mL/100 g or CBF > 100 mL/100 g/min were characterized as vessel voxels and were excluded from the quantitative measurements. Results. The segmented brain parenchyma with normal perfusion was consistent with the angiographic findings for each patient. We confirmed the necessity of dual thresholds including CBF and CBV for proper removal of vessel voxels. The scaling factors were 0.208 ± 0.041 for CBV, and 0.168 ± 0.037, 0.172 ± 0.037 for CBF calculated using standard and circulant singular value decomposition techniques, respectively. Conclusion. The automatic scaling and vessel removal techniques provide an alternative method for obtaining improved quantitative assessment of CBV and CBF in patients with thromboembolic cerebral arterial disease. Michael Mu Huo Teng, I-Chieh Cho, Yi-Hsuan Kao, Chi-Shuo Chuang, Fang-Ying Chiu, and Feng-Chi Chang Copyright © 2013 Michael Mu Huo Teng et al. All rights reserved. Differential Temporal Evolution Patterns in Brain Temperature in Different Ischemic Tissues in a Monkey Model of Middle Cerebral Artery Occlusion Tue, 02 Oct 2012 13:42:41 +0000 Brain temperature is elevated in acute ischemic stroke, especially in the ischemic penumbra (IP). We attempted to investigate the dynamic evolution of brain temperature in different ischemic regions in a monkey model of middle cerebral artery occlusion. The brain temperature of different ischemic regions was measured with proton magnetic resonance spectroscopy (1H MRS), and the evolution processes of brain temperature were compared among different ischemic regions. We found that the normal (baseline) brain temperature of the monkey brain was 37.16°C. In the artery occlusion stage, the mean brain temperature of ischemic tissue was 1.16°C higher than the baseline; however, this increase was region dependent, with 1.72°C in the IP, 1.08°C in the infarct core, and 0.62°C in the oligemic region. After recanalization, the brain temperature of the infarct core showed a pattern of an initial decrease accompanied by a subsequent increase. However, the brain temperature of the IP and oligemic region showed a monotonously and slowly decreased pattern. Our study suggests that in vivo measurement of brain temperature could help to identify whether ischemic tissue survives. Zhihua Sun, Jing Zhang, Yingmin Chen, Yunting Zhang, Xuejun Zhang, Hong Guo, and Chunshui Yu Copyright © 2012 Zhihua Sun et al. All rights reserved. Quantifying Tumor Vascular Heterogeneity with Dynamic Contrast-Enhanced Magnetic Resonance Imaging: A Review Tue, 26 Apr 2011 14:44:53 +0000 Tumor microvasculature possesses a high degree of heterogeneity in its structure and function. These features have been demonstrated to be important for disease diagnosis, response assessment, and treatment planning. The exploratory efforts of quantifying tumor vascular heterogeneity with DCE-MRI have led to promising results in a number of studies. However, the methodological implementation in those studies has been highly variable, leading to multiple challenges in data quality and comparability. This paper reviews several heterogeneity quantification methods, with an emphasis on their applications on DCE-MRI pharmacokinetic parametric maps. Important methodological and technological issues in experimental design, data acquisition, and analysis are also discussed, with the current opportunities and efforts for standardization highlighted. Xiangyu Yang and Michael V. Knopp Copyright © 2011 Xiangyu Yang and Michael V. Knopp. All rights reserved. An Evaluation of Cellular Neural Networks for the Automatic Identification of Cephalometric Landmarks on Digital Images Thu, 10 Sep 2009 11:15:46 +0000 Several efforts have been made to completely automate cephalometric analysis by automatic landmark search. However, accuracy obtained was worse than manual identification in every study. The analogue-to-digital conversion of X-ray has been claimed to be the main problem. Therefore the aim of this investigation was to evaluate the accuracy of the Cellular Neural Networks approach for automatic location of cephalometric landmarks on softcopy of direct digital cephalometric X-rays. Forty-one, direct-digital lateral cephalometric radiographs were obtained by a Siemens Orthophos DS Ceph and were used in this study and 10 landmarks (N, A Point, Ba, Po, Pt, B Point, Pg, PM, UIE, LIE) were the object of automatic landmark identification. The mean errors and standard deviations from the best estimate of cephalometric points were calculated for each landmark. Differences in the mean errors of automatic and manual landmarking were compared with a 1-way analysis of variance. The analyses indicated that the differences were very small, and they were found at most within 0.59 mm. Furthermore, only few of these differences were statistically significant, but differences were so small to be in most instances clinically meaningless. Therefore the use of X-ray files with respect to scanned X-ray improved landmark accuracy of automatic detection. Investigations on softcopy of digital cephalometric X-rays, to search more landmarks in order to enable a complete automatic cephalometric analysis, are strongly encouraged. Rosalia Leonardi, Daniela Giordano, and Francesco Maiorana Copyright © 2009 Rosalia Leonardi et al. All rights reserved.