​Comparative Evaluation Of Pre-Operative Multidetector Computer Tomography Findings And Intraoperative Endoscopic Sinus Surgery Findings With Regard To Osteomeatal Complex In Patients With Chronic Rhinosinusitis

Background and Objective: Background and objective of the study were to determine how well the pre-operative multidetectorrow computed tomography (MDCT) findings and intraoperative endoscopic sinus surgery findings correlate in patients withchronic rhinosinusitis (CRS) and to assess the various anatomical variations of the osteomeatal complex in these patients.Materials and Methods: A total of 100 patients falling within the inclusion criteria with diagnosed CRS who had given consentfor participating in this study were analyzed. The study period was from January 2016 to December 2016. In these patients, adetailed history and examination were done, counseled regarding the necessity of MDCT scan imaging of the nose and sinusesand further about the need for endoscopic evaluation and functional endoscopic sinus surgery (FESS). Scans were evaluatedpreoperatively as per Lund–Mackay CT scan score and anatomic variants regarding OMC were noted. Later, intraoperativefindings were noted, and kappa statistics was used to analyze the agreement between MDCT and intraoperative endoscopicfindings.Results: Agger nasi, concha bullosa, medial and lateral deviation of the uncinate process and paradoxical middle turbinateshowed a very good correlation of agreement between pre-operative CT scan and operative findings. Excellent correlationwas found in case OMC obstruction, and there was a very good correlation of agreement between pre-operative CT scan andoperative findings.Conclusion: MDCT shows an increased sensitivity compared to routine CT in detecting OMC obstruction, and it had a verygood correlation with intraoperative findings. There was an excellent correlation between MDCT and intraoperative findingsin cases of all anatomic variants studied except concha bullosa. In conclusion, MDCT can help clinicians to better predict theOMC status pre-operatively and thereby guide FESS

Preoperative Radiologic Evaluation of Cholangiocarcinoma / 대한소화기학회지

In patients with cholangiocarcinoma, surgical resection with curative intent is the only way to achieve cure. Since surgical resection of cholangiocarcinomas is technically demanding, determination of resectability and accurate preoperative staging are crucial. For these purposes, high quality imaging including multidetector computed tomography and magnetic resonance imaging with magnetic resonance cholangiopancreaticography, is mandatory. This article will present recent advances in imaging techniques for cholangiocarginomas, potential pitfalls in imaging evaluation, and a checklist for preoperative radiologic assessment of resectability in these patients with an emphasis on perihilar cholangiocarinoma.

Imaging-Based Management of Acute Ischemic Stroke Patients: Current Neuroradiological Perspectives

Advances in imaging-based management of acute ischemic stroke now provide crucial information such as infarct core, ischemic penumbra/degree of collaterals, vessel occlusion, and thrombus that helps in the selection of the best candidates for reperfusion therapy. It also predicts thrombolytic efficacy and benefit or potential hazards from therapy. Thus, radiologists should be familiar with various imaging studies for patients with acute ischemic stroke and the applicability to clinical trials. This helps radiologists to obtain optimal rapid imaging as well as its accurate interpretation. This review is focused on imaging studies for acute ischemic stroke, including their roles in recent clinical trials and some guidelines to optimal interpretation.

Pre-operative staging of rectal cancer using multi-detector row computed tomography with multiplanar reformations: Single center experience.

BACKGROUND: Technical advancement in imaging has helped to stage and plan treatment modality for carcinoma rectum with still some objectives controversial. AIMS: The aim of our study was to evaluate the accuracy of multidetector row computed tomography (MDCT) with multiplanar reformations in the pre‑operative staging of rectal carcinoma and correlation with intraoperative and histopathologic staging of retrieved specimen with respect to the depth of tumor invasion (T‑staging), lymph node metastasis (N‑staging) and mesorectal fascia (MRF) involvement. MATERIALS AND METHODS: The study was a prospective one and consisted of 52 patients with biopsy proved rectal carcinoma. MDCT studies were performed on a 64‑slice computed tomography system. Images were reconstructed in axial, coronal and sagittal planes. MDCT findings were compared with intraoperative and pathologic (reference standard) findings. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were assessed. RESULTS: The diagnostic accuracy of MDCT for T1/T2, T3 and T4 lesions was 77%, 86.5% and 100%, respectively. For perirectal lymph node metastasis (N+), the diagnostic accuracy of MDCT was 84.1%. The diagnostic accuracy of MDCT for MRF involvement was 91%. CONCLUSION: MDCT is a reliable radiological tool for local staging of rectal cancer with excellent accuracy rates for T and N‑staging of rectal cancer.

Application of multidetector-row computed tomography angiography in soft tissue defect of lower extremities with perforator flap / 中华显微外科杂志

Objective Significant anatomical variability of perforator vessel can affect the perforator flap application in accuracy,randomness,and the final result of the repair.Multidetector-row computed tomography angiography(MDCTA) is an useful preoperative identification of perforator vessel,and which is discussed as a guidance to the clinical utilities of free-style perforator flap in lower extremity.Methods From February 2011 to December 2012,forty patients with soft tissue defects in lower extremity were treated.Preoperatively MDCTA was performed on all patients to assess features of the perforating branches,including their location,caliber,course,structure and relationship of neighboring tissues.Various perforator flaps for soft tissue reconstruction using dominant perforator vessels were designed.Moreover the coincidence rate between preoperative and intraoperative location of the perforator vessel was evaluated.Results All the flaps which consisted of 19pedicled propeller flaps and 21 free flaps survived postoperatively.Only 1 case which involved the descending genicular artery perforator flap presented with a 2 cm × 2 cm distal necrosis which healed after regular dressing.For 37 cases,the donor site were primarily closed while partial skin grafting was performed in 3 cases.The rate of coincidence between the preoperative and intraoperative location of perforating branches was 97.5％.Conclusion Preoperative MDCTA can provide precise anatomical information on the perforator vessel.For sofi tissue defects reconstruction in the lower extremity,MDCTA makes the flap design easier and more accurate,and the surgery simpler and safer,thereby reducing damage to donor site and achieving the best repair.

Imaging modalities in head-and-neck cancer patients.

Accurate staging and timely assessment is critical in head-and-neck cancer patients for formulating the appropriate treatment strategy. Therefore, optimizing pretreatment imaging for diagnosis is of great importance. Computerized tomography (CT), introduced in the early 70s, followed by magnetic resonance imaging (MRI) and positron emission tomography (PET), refinements in ultrasonography (USG), advances in nuclear medicine, and applications such as sentinel node lymphoscintigraphy have greatly added to diagnostic accuracy. Post-treatment CT or MRI is of value when a recurrent tumor is suspected. It can confirm the presence of such a lesion and determine its extent. This is important information for determining the possibility of salvage therapy.

Incidence of Venous Thromboembolism Using 64 Channel Multidetector Row Computed Tomography-Indirect Venography and Anti-Coagulation Therapy after Total Knee Arthroplasty in Korea

PURPOSE: This study evaluated the incidence of a venous thromboembolism (VTE) after total knee arthroplasty (TKA) using multidetector row computed tomography-indirect venography (MDCT-indirect venography) and assessed the efficacy of anti-coagulation therapy. MATERIALS AND METHODS: We enrolled 118 patients with 126 cases of TKA. The average age of the patients was 68.4 years. We used 64 channel MDCT-indirect venography for the detection of VTE. We treated selectively proximal deep vein thrombosis (DVT) or pulmonary thromboembolism (PTE) cases according to the results of MDCT-indirect venography. We re-evaluated the change in VTE using follow-up MDCT-indirect venography after 3 months. RESULTS: We identified VTE in 35.7%. DVT only was identified in 22.2% including 8 cases of proximal DVT and 20 cases of distal DVT. PTE without DVT was identified in 4.8%, and combined DVT and PTE in 8.7%. All patients with PTE were asymptomatic, but 4 DVT patients had signs of leg swelling. After anti-coagulation therapy, 20 patients showed complete resolution in 16 cases, improvement in 3 cases and one case showed a new distal DVT. CONCLUSIONS: The incidence of VTE after primary TKA was 35.7% in Korea. Furthermore, anti-coagulation therapy for proximal DVT and PTE patients may be a useful method for preventing the occurrence of a fatal PTE.

Coronary MDCT and MRI / 임상당뇨병

Newer accurate, noninvasive coronary artery disease (CAD) screening methods, such as multi-detector computed tomography (MDCT) and magnetic resonance imaging (MRI), both show promise and have increased in popularity, although neither technique is currently recommended for routine use in the diagnosis of CAD in asymptomatic diabetic patients. MDCT has images acquired at high temporal and spatial resolution and has enabled cardiovascular medicine to enter the CT imaging era. This test infers the presence of coronary atherosclerosis by measuring the amount of calcium in coronary arteries and by direct visualization of luminal stenoses. MDCT (especially with 64 slices or greater CT) has developed as an effective alternative to invasive coronary angiography for the detection of CAD. It can be used as a highly sensitive screening modality that achieves high diagnostic accuracy for the detection of significant CAD. Cardiac MRI makes possible the noninvasive visualization of the major epicardial coronary arteries without ionizing radiation or assessment of myocardial perfusion. Cardiac MRI techniques provide an alternative to radionuclide methods, which are still the diagnostic standard for the assessment of myocardial perfusion because they are well established, particularly for the assessment of cardiac function.

Earthquake-related pelvic crush fracture vs. non-earthquake fracture on digital radiography and MDCT: a comparative study

OBJECTIVE: To determine the features of earthquake-related pelvic crush fractures versus non-earthquake fractures with digital radiography and multidetector row computed tomography. METHODS: One hundred and sixty-seven survivors with pelvic crush fractures in the 2008 Sichuan earthquake were entered in our study as the earthquake-related group (139 underwent digital radiography, 28 underwent multidetector row computed tomography); 70 victims with non-earthquake pelvic fractures were enrolled into this study as the non-earthquake group (54 underwent digital radiography, 16 underwent multidetector row computed tomography). Data were reviewed retrospectively between groups, focusing on anatomic distributions, status of pelvic bone fractures, numbers of pelvic bones involved, and classification of pelvic ring fractures according to the Tile classification system. RESULTS: Pelvic fractures occurred more frequently in the pubis in the earthquake-related group than in the non-earthquake group (135/167, 81 percent vs. 48/70, 69 percent). In addition, comminuted fractures were more common in the earthquake-related group than in the non-earthquake group (55/167, 33 percent vs. 10/70, 14 percent). Multiple fractures were less common in the earthquake-related group than in the non-earthquake group (81/167, 49 percent vs. 46/70, 66 percent). Regarding the classification of pelvic ring fractures, Type C predominantly composed of subtype C3 occurred more frequently (64/167, 38 percent vs. 12/70, 17 percent), and Type A was less common in the earthquake-related group than in the non-earthquake group (31/167, 19 percent vs. 23/70, 32 percent). All differences were statistically significant (p<0.05). No difference was found in Type B fractures between the groups (72/167, 43 percent vs. 35/70, 50 percent). CONCLUSION: Earthquake-related pelvic crush fractures can be characterized by a high incidence of pelvic fractures occurring in the pubis, comminuted fractures, and Type C fractures predominantly composed by subtype C3, despite a low incidence of multiple fractures.

Using Multidetector-Row CT for the Diagnosis of Afferent Loop Syndrome Following Gastroenterostomy Reconstruction

PURPOSE: To assess the clinical manifestations and multidetector-row computed tomography (MDCT) findings of afferent loop syndrome (ALS) and to determine the role of MDCT on treatment decisions. MATERIALS AND METHODS: From January 2004 to December 2008, 1,100 patients had undergone gastroenterostomy reconstruction in our institution. Of these, 22 (2%) patients were diagnosed as ALS after surgery that included Roux-en-Y gastroenterotomy (n=9), Billroth-II gastrojejunostomy (n=7), and Whipple's operation (n=6). Clinical manifestations and MDCT features of these patients were recorded and statistically analyzed. The presumed etiologies of obstruction shown on the MDCT were correlated with clinical information and confirmed by surgery or endoscopic biopsy. RESULTS: The most common clinical symptom was acute abdominal pain, presenting in 18 patients (82%). We found that a fluid-filled C-shaped afferent loop in combination with valvulae conniventes projecting into the lumen was the most common MDCT features of ALS. Malignant causes of ALS, such as local recurrence and carcinomatosis, are the most common etiologies of obstruction. These etiologies and associated complications can be predicted 100% by MDCT. CONCLUSION: Our results suggest that MDCT is a reliable modality for assessing the etiologies of ALS and guiding treatment decisions.

Pitfalls in the use of Multidetector Row CT Angiography for Identification of Intracranial Vascular Abnormalities : Focus on the Various Radiological Findings / 대한뇌혈관외과학회지

OBJECTIVE: Multidetector-Row computed tomographic angiography (MDCTA) is a promising method for detection and surgical planning of intracranial vascular abnormalities. However, there are several problems, such as image degradation due to inevitable patients movement, venous contamination, kissing vessel artifact, demonstration of venous structures mimicking aneurysm and bone artifacts. The purpose of our study is to review our recent experience with false negative or positive cases on MDCTA. METHODS: Between May 2007 and May 2010, 259 consecutive patients, who were diagnosed with intracranial aneurysms or other vascular abnormalities by MDCTA, were retrospectively reviewed. Among the 259 patients, 172 patients who underwent digital subtraction angiography (DSA), which was considered as the standard of reference, were included in the study. Two neuroradiologists and two neurosurgeons evaluated independently and separately all of the MDCTA images. RESULTS: A total 26 cases (15.3%) were revealed abnormal vascular findings on MDCTA. There were 11 false negatives on MDCTA including incomplete scanning range of lesion site (n=3), a blood blister aneurysm (n=1), severe vasospasm (n=4) and bone artifacts (n=3). Also there were 15 false positives on MDCTA; venous contamination over the lesion site (n=6), focal dilation of the bifurcation or branching site of major vessels (n=6) and poor quality of the images due to inevitable patients movement (n=3). CONCLUSIONS: MDCTA is clearly not the total answer for aneurysm diagnosis. We recommend that MDCTA scanning range is planned to encompass the whole intracerebral vasculature. Close attention to image acquisition and interpretation are required to reduce errors in MDCTA of intracranial aneurysms.

Angiotomografia com múltiplos detectores no diagnóstico de drenagem venosa pulmonar anômala: experiência inicial / Multidetector-row computed tomography angiography for the diagnosis of anomalous pulmonary venous drainage: an initial experiment

OBJETIVO: Demonstrar que a angiotomografia computadorizada com múltiplos detectores é um método efetivo e não invasivo para o diagnóstico de drenagem venosa pulmonar anômala. MATERIAIS E MÉTODOS: Estudo retrospectivo de 2.905 angiotomografias computadorizadas com múltiplos detectores cardíacas realizadas em nosso serviço no período de julho de 2003 a novembro de 2007. Destas, 393 foram destinadas para avaliar cardiopatias congênitas e as 2.512 restantes, para analisar as artérias coronárias. RESULTADOS: Foram encontrados 21 casos de drenagem venosa pulmonar anômala, sendo 7 (33,3 por cento) do tipo total e 14 (66,7 por cento) do tipo parcial. Das drenagens venosas pulmonares anômalas totais, três foram do tipo supracardíaco, três do tipo infracardíaco e uma do tipo cardíaco. CONCLUSÃO: A angiotomografia computadorizada com múltiplos detectores tem demonstrado fundamental importância no diagnóstico destas anomalias, principalmente por se tratar de método não invasivo capaz de analisar estruturas intra e extracardíacas e por permitir um estudo completo da anatomia torácica, contribuindo sobremaneira na conduta cirúrgica e, consequentemente, no prognóstico destes pacientes, especialmente por diagnosticar malformações não suspeitadas clinicamente.

OBJECTIVE: We aimed to determine if multidetector-row computed tomography angiography is an effective and non-invasive method for diagnosing anomalous pulmonary venous drainage. MATERIALS AND METHODS: We performed a retrospective review of 2,905 cases from July 2003 to November 2007 in which cardiac multidetector-row computed tomography angiography was used. Of the cases, 393 evaluated congenital cardiopathy, with the others (2,512) evaluating the coronary arteries. RESULTS: Anomalous pulmonary venous drainage was found in 21 cases, with 7 (33.3 percent) from total anomalous pulmonary venous drainage (3 supracardiac, 3 infracardiac and 1 cardiac), and 14 (66.7 percent) from partial anomalous pulmonary venous drainage. CONCLUSION: Multidetector-row computed tomography angiography can be useful for diagnosing the described anomalies because of its non-invasiveness, and its ability to evaluate intra- and extra-cardiac structures. The technique allows a thorough study of the thoracic anatomy and contributes to surgical conduct, consequently improving patient prognosis, in particular by allowing the diagnosis of clinically unsuspected malformations.

Multidetector row computed tomography evaluation of the micropig kidney as a potential renal donor

Multidetector row computed tomography (MDCT) provides anatomical information about the kidney and other internal organs. Presently, the suitability of 64-channel MDCT to assess the kidney of healthy micropigs was evaluated. Morphological evaluations of the kidney and the major renal vessels of six healthy micropigs were carried out using MDCT, recording kidney volume and the diameter and length of renal arteries and veins. The mean diameters and lengths of the renal artery were 0.44 +/- 0.05 and 4.51 +/- 0.55 cm on the right side and 0.46 +/- 0.06 and 3.36 +/- 0.27 cm on the left side, respectively. The mean diameters and lengths of the renal vein were 1.44 +/- 0.52 and 4.22 +/- 1.29 cm on the right side and 1.38 +/- 0.17 and 5.15 +/- 0.87 cm on the left side, respectively. The mean volume of the right kidney was 79.3 +/- 14.5 mL and of the left kidney was 78.0 +/- 13.9 mL. The data presented in this study suggest that the MDCT offers a noninvasive, rapid, and accurate method for the evaluation of the renal anatomy in living kidney donors. It also provides sufficient information about extra-renal anatomy important for donor surgery and determination of organ suitability.

64-Channel multi-detector row CT angiographic evaluation of the micropigs for potential living donor lung transplantation

Micropigs are the most likely source animals for xenotransplantation. However, an appropriate method for evaluating the lung of micropigs had not been established. Therefore, this study was performed to evaluate the feasibility of 64-channel multi-detector row computed tomography (MDCT) to measure the diameter of the pulmonary arteries and the lung volume in micropigs. The mean diameters of the trachea, and left and right bronchi were 1.6 +/- 0.17, 1.18 +/- 0.14, and 1.1 +/- 0.11 cm, respectively. The mean diameters of the main, right, and left pulmonary arteries were 1.38 +/- 0.09, 1.07 +/- 0.26, and 0.98 +/- 0.13 cm and the diameters of right, left, and common inferior pulmonary veins were 0.97 +/- 0.20, 0.76 +/- 0.20, and 1.99 +/- 0.26 cm, respectively. The mean lung volume was 820.3 +/- 77.11 mL. The data presented in this study suggest that the MDCT may be a noninvasive, rapid, and accurate investigational method for pulmonary anatomy in living lung donors.

Estudio vascular renal por TC multidetector de 64 canales / 64-Multidetector row CT for the Renal Vascular Study

Objetivo: Mostrar las diversas variantes anatómicas vasculares tanto arteriales como venosas en el estudio angiográfico renal por tomografìa computada multidetector (TCMD) de 64 canales, dada su implicancia en un eventual planeamiento quirúrgico. Material y métodos: Evaluamos retrospectivamente 26 estudios realizados con tomógrafo Philips Brilliance de 64 canales. Se obtuvieron secuencias sin contraste y postcontraste e.v. en fases arterial y venosa, administrado con bomba inyectora doble cabezal. Para una fase arterial apropiada se utilizó técnica de bolus track. Las imágenes fueron posteriormente procesadas en Workstation Philips Brilliance 190P en un tiempo promedio de 30 minutos y reconstruidas con técnicas MIP y volumétrica. Resultados: Dentro de las variantes anatómicas arteriales, encontramos: bifurcaciones prehiliares (n=3), arterias accesorias (n=4) y arterias polares (n=9). Dentro de las variantes venosas fueron halladas: venas renales múltiples (n=5), venas circumaórticas (n=2), retroaórticas (n=2) y vena tributaria lumbar prominente (n=1). Conclusión: El estudio vascular renal adquiere importancia en el planeamiento quirúrgico en casos de nefrectomías parciales, laparoscópicas y en el transplante renal. Esto otorga suma utilidad al estudio de TCMD de 64 canales por su eficacia diagnóstica, dada la alta calidad de las reconstrucciones obtenidas, llegando a igualar a la angiografía digital, sin ser un método invasivo.

Purpose: To show the wide range of anatomical vascular variants, arterial and venous, that can be seen in the angiographic renal study using 64-multidetector-row computed tomography (64-MDCT), due to its importance in an eventual surgical planning. Material and Methods: We have evaluated retrospectively 26 studies that have been done using a 64 channels Philips Brilliance CT scanner. We have obtained non enhanced and both in arterial and venous enhanced sequences. For the injection of the contrast material we have used a double head injector bomb. The arterial phase was acquired using the bolus track technique. The raw data has then been post processed in a 190P Philips Brilliance workstation in a mean time of 30 minutes. The reconstructions have been obtained both with MIP and volumetric technique. Conclusion: The renal vascular study has importance for the surgical planning in cases of parcial nephrectomies or laparoscopic nephrectomies as well as in renal transplant. This makes the 64-MDCT a very useful non invasive imaging tool due to its high accuracy similar to digital angiography.

Comparative evaluation of computed tomography for dental implants on the mandibular edentulous area / 대한구강악안면방사선학회지

PURPOSE: The purpose of this study was to evaluate the clinical usefulness of the recently developed multi-detector computed tomography and cone beam computed tomography in pre-operative implant evaluation, by comparing them with the single detector computed tomography, already confirmed for accuracy in this area. MATERIALS AND METHODS: Five partially edentulous dry human mandibles, with 1x1 mm gutta percha cones, placed in 5 mm intervals posterior to the mental foramen on each side of the buccal part of the mandible, were used in this study. They were scanned as follows: 1) Single detector computed tomography: slice thickness 1 mm, 200 mA, 120 kV 2) Multi-detector computed tomography: slice thickness 0.75 mm, 250 mA, 120 kV 3) Cone beam computed tomography: 15 mAs, 120 kV Axial images acquired from three computed tomographies were transferred to personal computer, and then reformatted cross-sectional images were generated using V-Implant 2.0(R) (CyberMed Inc., Seoul, Korea) software. Among the cross-sectional images of the gutta percha cone, placed in the buccal body of the mandible, the most precise cross section was selected as the measuring point and the distance from the most superior border of the mandibular canal to the alveolar crest was measured and analyzed 10 times by a dentist. RESULTS: There were no significant intraobserver differences in the distance from the most superior border of the mandibular canal to the alveolar crest (p>0.05). There were no significant differences among single detector computed tomography, multi-detector computed tomography and cone beam computed tomography in the distance from the most superior border of the mandibular canal to the alveolar crest (p>0.05). CONCLUSION: Multi-detector computed tomography and cone beam computed tomography are clinically useful in the evaluation of pre-operative site for mandibular dental implants, with consideration for radiation exposure dose and scanning time.

Solitary Fibrous Tumor of the Trachea: CT Findings with a Pathological Correlation

We present the multidetector CT findings with a pathologic correlation for the case of a solitary fibrous tumor located in the trachea. The MDCT revealed a well-circumscribed intraluminal mass arising from the trachea, with strong nodular enhancement in the periphery of the mass. The enhancement pattern of the mass corresponded histopathologically to a focal hypocellular area in the center and prominent blood vessels along the periphery of the mass. We also present volume-rendered and virtual bronchoscopic images of this rare submucosal tracheal tumor.

Reviews of Radiation Protection and Shielding for Computed Tomography in Foreign Countries / 의학물리

A computed tomography (CT) is a powerful system for the effectively fast and accurate diagnosis. The CT system, therefore, has used substantially and developed for improving the performance over the past decade, resulting in growing concerns over the radiation dose from the CT. Advanced CT techniques, such as a multidetector row CT scanner and dual energy or dual source CT, have led to new clinical applications that could result in further increases of radiation does for both patients and workers. The objective of this study was to review the international guidelines of the shielding requirements for a CT facility required for a new installation or when modifying an existing one. We used Google Search Engine to search the following keywords: computed tomography, CT regulation or shield or protection, dual energy or dual source CT, multidetector CT, CT radiation protection, and regulatory or legislation or regulation CT. In addition, we searched some special websites, that were provided for sources of radiation protection, shielding, and regulation, RSNA, AAPM, FDA, NIH, RCR, ICRP, IRPA, ICRP, IAEA, WHO (See in Table 1 for full explanations of the abbreviations). We finally summarized results of the investigated materials for each country. The shielding requirement of the CT room design was very well documented in the countries of Canada, United States of America, and United Kingdom. The wall thickness of the CT room could be obtained by the iso-exposure contour or the point source method. Most of documents provided by international organizations were explained in importance of radiation reduction in patients and workers. However, there were no directly-related documents of shielding and patient exposure dose for the dual energy CT system. Based international guidelines, the guideline of the CT room shielding and radiation reduction in patients and workers should be specified for all kinds of CT systems, included in the dual energy CT. We proposed some possible strategies in this paper.

Comparison of cardiac function and coronary angiography between conventional pigs and micropigs as measured by multidetector row computed tomography

Pigs are the most likely source animals for cardiac xenotransplantation. However, an appropriate method for estimating the cardiac function of micropigs had not been established. Computed tomography (CT) analysis aimed at estimating cardiac function and assessing the coronary arteries has not been carried out in micropigs. This study determined the feasibility of evaluating cardiac function in a micropig model using multidetector row computed tomography (MDCT) and compared the cardiac function values with those of conventional pigs. The mean age of the conventional pigs and micropigs was approximately 80 days and approximately 360 days, respectively. The mean body weight in the conventional pigs and micropigs was 29.70 +/- 0.73 and 34.10 +/- 0.98 kg, respectively. Cardiac MDCT detected ejection fractions of 52.93 +/- 3.10% and 59.00 +/- 5.56% and cardiac outputs of 1.46 +/- 0.64 l/min and 1.21 +/- 0.24 l/min in conventional pigs and micropigs, respectively. There were no significant differences in cardiac function between conventional pigs and micropigs in the reconstructed CT images. There were also no differences in the coronary angiographic images obtained by MDCT. It is expected that the results of this study will help improve understanding of cardiac function in micropigs. The data presented in this study suggest that MDCT is a feasible method for evaluating cardiac function in micropigs.

Early and Delayed Myocardial Enhancement in Myocardial Infarction Using Two-Phase Contrast-Enhanced Multidetector-Row CT

OBJECTIVE: The purpose of this study was to describe the myocardial enhancement patterns in patients with myocardial infarction using two-phase contrast-enhanced multidetector-row computed tomography (MDCT). MATERIALS AND METHODS: Twenty-three patients with clinically proven myocardial infarction (17 acute myocardial infarction [AMI] and 6 chronic myocardial infarction [CMI]) were examined with two-phase contrast-enhanced ECG-gated MDCT. The presence, location, and patterns of myocardial enhancement on two-phase MDCT images were compared with infarcted myocardial territories determined by using electrocardiogram, echocardiography, thallium-201 single photon emission computed tomography, catheter and MDCT coronary angiography. RESULTS: After clinical assessment, the presence of myocardial infarctions were found in 27 territories (19 AMI and 8 CMI) of 23 patients. Early perfusion defects were observed in 30 territories of all 23 patients. Three territories not corresponding to a myocardial infarction were detected in three patients with AMI and were associated with artifacts. Fourteen of perfusion defects were in the left anterior descending artery territory, four in the left circumflex artery territory, and nine in the right coronary artery territory. Delayed enhancement was observed in 25 territories (17 AMI and 8 CMI) of 21 patients. Delayed enhancement patterns were variable. Transmural early perfusion defects (n =12) were closely associated with transmural late enhancement (n = 5) and subendocardial residual defect with subepicardial late enhancement (n = 5). CONCLUSION: Myocardial infarction showed early perfusion defects and variable delayed enhancement patterns on two-phase contrast-enhanced MDCT. Delayed enhancement technique of MDCT could provide additional information of the location and extent of infarcted myocardium, and could be useful to plan appropriate therapeutic strategies in patients with AMI.