[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-149517-105":59,"doc-detail-149517-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","arterial-input-function-influence-of-vessel-misregistration-induced-by-paramagnetic-contrast-agents-measured-with-epi","Arterial Input Function - Influence of Vessel Misregistration Induced by Paramagnetic Contrast Agents Measured with EPI","","Arterial input function measurement is essential for absolute quantification of perfusion using dynamic susceptibility contrast (DSC). Paramagnetic Gd-based agents not only affect R2* but also alter the local magnetic field, producing vessel misregistration whose magnitude scales with bandwidth and contrast-agent susceptibility and concentration. The study analyzes DSC datasets and applies a computer model to compute temporal profiles of distorted AIFs using gradient-echo EPI acquisitions.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":40,"@type":76,"position":81},"https://docshare.wps.com/document/research-report/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/arterial-input-function-influence-of-vessel-misregistration-induced-by-paramagnetic-contrast-agents-measured-with-epi/149517/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/arterial-input-function-influence-of-vessel-misregistration-induced-by-paramagnetic-contrast-agents-measured-with-epi/149517.png","ImageObject",300,407,{"name":92,"@type":93},"Valentina","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-09-18","2026-08-27",true,{"@type":102,"interactionType":103,"userInteractionCount":29},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"Why must the arterial input function (AIF) be measured for absolute perfusion quantification in DSC-MR?","Question",{"text":112,"@type":113},"AIF characterizes the temporal bolus passage through a feeding artery and is used to normalize voxel concentration-time curves for computing absolute blood flow and blood volume.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"How do paramagnetic contrast agents lead to vessel misregistration during EPI-based AIF measurements?",{"text":117,"@type":113},"Gd-containing agents change the local magnetic field in addition to R2*, shifting MR signal registration in a way that depends on sequence bandwidth and increases with susceptibility and contrast concentration.",{"name":119,"@type":110,"acceptedAnswer":120},"What was the main effect of using two different Gd injection schemes on AIF signal behavior and AIF accuracy?",{"text":121,"@type":113},"With scheme (A), many AIF pixels showed distorted signal time curves and vessels shifted about 5–6 mm, limiting usable pixels. With scheme (B), vessel dislocation decreased, more pixels showed normal curves, and perfusion maps could be calculated accurately for both schemes using signal drop data from brain slices.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},149517,1787801653,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":39,"category_name":40,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":29,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":8,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":129,"read_time":81},13056703020460,"https://ap-avatar.wpscdn.com/avatar/be000253dac470eee5d?_k=1778207105932848923","The influence of vessel misregistration induced by paramagnetic contrast agents on the arterial input  \nfunction measured with EPI  \nMartin RAUSCH1  \n1University Hospital/Kantonsspital Basel, Dept. of Radiology, Basel, Switzerland;  \nIntroduction  \nFor absolute quantification of perfusion data using the dynamic susceptibility contrast (DSC) technique, the arterial input function (AIF) has to be measured. This function describes the temporal profile of the bolus passage through a feeding artery and is used to normalize the concentration time curves of voxels located in the parenchyma for which values of absolute blood flow and blood volume should be obtained. In most cases EPI is used to measure the signal change induced by the contrast agent in the feeding artery and in one ore more brain slices with sufficient temporal resolution. However, Gdcontaining contrast agents do not only increase R2*. They also increase the local magnetic field, which causes a misregistration of the MR signal. This misregistration depends on the bandwidth of the imaging sequence and increases linearly with the volume susceptibility of the contrast agent and its concentration. Assuming that the contrast agent is injected as a short bolus, high peak concentrations must be expected. Since single shot EPI sequences provide only a very low bandwidth in phase encoding direction of around 1kHz, prominent signal misregistration might be expected.  \nIn the present study we analyzed the vessel dislocation in DSC-datasets and used a computer model to calculate the temporal profile of distorted arterial input functions.  \nMethods  \nExperiments have been carried out on a 1.5 T Symphony MR system (Siemens Medical Systems, Erlangen, Germany) using a gradient echo (GE) EPI sequence. 18 slices with a matrix size of 64x64 pixels covering almost the whole brain have been measured. The echo spacing was 1.0 msec. The FOV was 20 cm in both directions and the slice thickness was 5 mm. An additional slice of same thickness was positioned in the neck region to obtain an AIF from the ICA and VA. The raw data were zero-filled to 128x128 pixels before reconstruction. The TE for \"brain slices\" was 52 msec. For the AIF-slice a reduced trim gradient for phase encoding was implemented to achieve a reduced TE of 15 msec for this slice.  \nA single dose of Gd-DOTA (Dotarem, Guerbet, Paris) was injected into the antecubital vein by means of a power injector (Medrad Spectris, Indianola, PA) . Two different injection schemes were used:(A) Injection rate 4 ml/sec; 0.1 mMol/Gd/kg body weight (B) Injection rate 2 ml/sec; 0.05 mMol/Gd/kg body weight. The injection of the contrast agent was followed by a NaCl flush of 30 ml injected at the same rate. Data acquisition started 20 seconds prior to Gd-DOTA injection. Fifty volumes were acquired during a period of 100 sec each comprising 18 brain- and one AIF-slice. Post-processing of the data comprised digital low pass filtering of the signal time curves, fitting of a gamma variate function to the concentration time curves and calculation of rCBF, rCBV and MTT maps.  \nThe pixels representing the AIF were selected by an early and strong signal drop from the AIF-slice. For the computer model, we used the theory presented in [1] . Additionally, a bandwidth in phase encoding direction of 1 kHz was used.  \nResults  \nFor injection scheme (A) the shape of the signal time curves of a majority of the AIF defining pixels appeared distorted. Depending on the position of the pixel along the phase-encoding direction, different forms of distortions were observed. Some showed a strong dispersion, others displayed a transient signal increase during the passage of the contrast agent. A third group displayed a signal increase at the beginning and the end of the bolus passage. Inspection of the image series obtained for the feeding arteries demonstrated that the vessels were shifted in phase encoding direction for about 5-6 mm during the bolus passage.  \nFor inject","cbCairVaJs2JyfDv","https://ap.wps.com/l/cbCairVaJs2JyfDv","pdf",51996,"English","# Introduction\n# Methods\n# Results\n# Discussion\n# References","[{\"question\":\"Why must the arterial input function (AIF) be measured for absolute perfusion quantification in DSC-MR?\",\"answer\":\"AIF characterizes the temporal bolus passage through a feeding artery and is used to normalize voxel concentration-time curves for computing absolute blood flow and blood volume.\"},{\"question\":\"How do paramagnetic contrast agents lead to vessel misregistration during EPI-based AIF measurements?\",\"answer\":\"Gd-containing agents change the local magnetic field in addition to R2*, shifting MR signal registration in a way that depends on sequence bandwidth and increases with susceptibility and contrast concentration.\"},{\"question\":\"What was the main effect of using two different Gd injection schemes on AIF signal behavior and AIF accuracy?\",\"answer\":\"With scheme (A), many AIF pixels showed distorted signal time curves and vessels shifted about 5–6 mm, limiting usable pixels. With scheme (B), vessel dislocation decreased, more pixels showed normal curves, and perfusion maps could be calculated accurately for both schemes using signal drop data from brain slices.\"}]","Arterial Input Function - Influence of Vessel Misregistration Induced by Paramagnetic Contrast Agents Measured with EPI | PDF"]