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Repeated Imaging (repeated + imaging)
Selected AbstractsReducing morphological variability of the cervical carotid artery in serial magnetic resonance imaging using a head and neck immobilization deviceJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2008Brian E. Chapman PhD Abstract Purpose To evaluate how well a head and neck immobilization device performed in reducing lumen morphology variability in repeated MR imaging of the carotid artery. Materials and Methods Quantitative measures of lumen and plaque characteristics may be important for longitudinal management of carotid atherosclerotic disease. However, quantitative measurements of the carotid artery are limited by their dependence on patient positioning, which can be quite variable. We created a head and neck immobilization device to reduce the variability of patient positioning during MR imaging of the carotid artery. In this article we describe the design and use of the immobilization device and assess how well its use reduced variability in vascular orientation and measurements of the carotid lumen cross-sectional area. Evaluation was based on 15 subjects who were repeatedly imaged without the immobilization device and 14 subjects who were repeatedly imaged with the device. Results Use of the immobilization device decreased the orientation variability from 9.1° to 5.3° (P = 0.0006) and the variability (defined as the standard deviation divided by the mean) of the cross-sectional area decreased from 0.24 to 0.18 (P = 0.04). Conclusion Using the immobilization device effectively reduces variability in repeated imaging of the carotid arteries. J. Magn. Reson. Imaging 2008;28:258,262. © 2008 Wiley-Liss, Inc. [source] Coronary MR angiography: Respiratory motion correction with BACSPINJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2003Christopher J. Hardy PhD Abstract Purpose To improve the signal-to-noise ratio (SNR) of breath-held coronary magnetic resonance angiography (CMRA) without increasing the number or duration of breath holds. Materials and Methods In this BACSPIN (Breathing AutoCorrection with SPiral INterleaves) technique, a single breath-held electrocardiogram (ECG)-gated multi-slice interleaved-spiral data set is acquired, followed by repeated imaging of the same slices during free breathing. Each spiral interleaf from the breath-held data set is used as a standard for comparison with corresponding acquisitions at the same interleaf angle during free breathing. The most closely matched acquisitions are incorporated into a multi-slice, multi-average data set with increasing SNR over time. In-plane translations of the coronary artery can be measured and compensated for each accepted acquisition before combination with the other acquisitions. Results CMRA was performed on six volunteers, with improved SNR and minimal motional blurring. In some cases, breath holding could be dispensed with completely and the average respiratory position used as a reference. Conclusion BACSPIN provides a promising method for CMRA with improved SNR and limited breath-holding requirements. J. Magn. Reson. Imaging 2003;17:170,176. © 2003 Wiley-Liss, Inc. [source] Median liver lobe of woodchuck as a model to study hepatic outflow obstruction: a pilot studyLIVER INTERNATIONAL, Issue 9 2008Uta Dahmen Abstract Background: Hepatic vein outflow obstruction represents an important clinical problem in living-liver transplantation. An animal model is required to study the influence of outflow obstruction on the intrahepatic regulation of liver perfusion and the subsequent effects on liver injury and recovery during liver regeneration. The size of woodchucks enables the use of standard clinical imaging procedures. Aim: This study aims at describing hepatic vascular and territorial anatomy of the woodchuck liver based on a virtual three-dimensional (3D) visualization of the hepatic vascular tree. Methods: Woodchucks (n=6) were subjected to an all-in-one computed tomography (CT) after contrasting the vascular and the biliary tree. CT-images were used for 3D-reconstruction of hepatic and portal veins and calculation of the corresponding portal and hepatic vein territories and their respective volume using hepavision (MeVisLab). A virtual resection was performed following the Cantlie-line and territories at risk were calculated. Results: The median lobe of the woodchuck liver has a similar vascular supply and drainage as the human liver with two portal (right and left median portal vein) and three hepatic veins (left, middle and right median hepatic vein). The corresponding portal and hepatic vein subterritories are of a similar relative size compared with the human liver. Virtual splitting of the median lobe of the woodchuck liver revealed areas at risk of focal outflow obstruction, as observed clinically. Conclusion: The median liver lobe of the woodchuck represents, to a small extent, the hepatic vascular anatomy of the human liver and is therefore a suitable potential model to correlate repeated imaging of impaired liver perfusion with histomorphological findings of liver damage and regeneration. [source] CURRENT MANAGEMENT OF BLUNT SPLENIC TRAUMA IN CHILDRENANZ JOURNAL OF SURGERY, Issue 1-2 2006Stephen R. Thompson Background: Non-operative management of the great majority of blunt splenic injuries in children has become routine. Debate continues on the need for intensive care unit (ICU) admission, follow-up imaging and the duration of physical activity restrictions following injury. The purpose of this study was to review the recent experience of an Australian Paediatric Trauma Centre with splenic trauma to define current practice. Methods: A retrospective chart review of patients with splenic trauma admitted to the Children's Hospital at Westmead between November 1995 and December 2003. Results: A total of 39 patients with blunt splenic trauma were identified: 20 (51%) were multiply injured. Thirty-three (85%) children were managed non-operatively. The most common initial imaging method was computed tomography (n = 28, 72%). Fourteen patients (36%) were admitted to the ICU with a mean length of stay (LOS) of 4.1 days (range 1,13 days). The overall mean LOS was 10.8 days (range 1,43 days). Nineteen patients (50%) had imaging studies performed after diagnosis but before discharge. Further post-discharge imaging was carried out in 21 cases (54%). There were no deaths, but 10 patients developed complications. The mean documented activity restriction was 7.4 weeks (range 1,16 weeks). Conclusion: The majority of children who had suffered blunt splenic trauma were safely managed non-operatively outside an ICU. In stable patients, there appeared to be no benefits associated with repeated imaging following the diagnosis of splenic trauma. Physical activity restriction in excess of 3,4 weeks did not appear to be warranted. [source] | ||||||||||