Abstract:
:Weighting is the term most frequently used to describe magnetic resonance pulse sequences and the concept most commonly used to relate image contrast to differences in magnetic resonance tissue properties. It is generally used in a qualitative sense with the single tissue property thought to be most responsible for the contrast used to describe the weighting of the image as a whole. This article describes a quantitative approach for understanding the weighting of sequences and images, using filters and partial derivatives of signal with respect to logarithms of tissue property values. Univariate and multivariate models are described for several pulse sequences including methods for maximizing weighting and calculating both sequence and image weighting ratios. The approach provides insights into difficulties associated with qualitative use of the concept of weighting and a quantitative basis for assessing the signal, contrast, and weighting of commonly used sequences and images.
journal_name
J Comput Assist Tomogrjournal_title
Journal of computer assisted tomographyauthors
Yokoo T,Bae WC,Hamilton G,Karimi A,Borgstede JP,Bowen BC,Sirlin CB,Chung CB,Crues JV,Bradley WG,Bydder GMdoi
10.1097/RCT.0b013e3181d3449asubject
Has Abstractpub_date
2010-05-01 00:00:00pages
317-31issue
3eissn
0363-8715issn
1532-3145pii
00004728-201005000-00001journal_volume
34pub_type
杂志文章,评审abstract::A 45-year-old patient with focal intrahepatic extramedullary hematopoiesis is presented in which the liver was imaged by CT, ultrasound, and MR. The appearance of the lesions on MR consisted of slightly increased signal on T2-weighted images with heterogeneous enhancement of some of the lesions during bolus infusion o...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:
更新日期:1991-07-01 00:00:00
abstract::A simple technique using stereotactic needle placement for retrobulbar anesthesia is reported. The method utilizes a CT-guided stereotactic device that permits precise intraconal injection of local anesthetics; in addition, the risk of injury to muscles, vessels, eyeglobe, or optic nerve is substantially reduced. ...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/00004728-199009000-00043
更新日期:1990-09-01 00:00:00
abstract:BACKGROUND AND AIMS:To prospectively determine the accuracy of liver fat quantification with magnetic resonance imaging (MRI). PATIENTS AND METHODS:The population consisted of 40 patients (mean age, 52.5 years; range, 23-78 years). The same day, all patients underwent MRI and ultrasonography-guided liver biopsy. The h...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/RCT.0b013e318199d883
更新日期:2009-09-01 00:00:00
abstract::This is a comparison of the ability of two quantitative magnetic resonance (MR) indices: (a) the second echo signal drop (SESD) (a simplified index of T2 relaxation times that we have developed); and (b) the previously described lesion/liver signal intensity ratio (LLR) to provide histologic diagnosis in hepatic lesio...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:
更新日期:1990-03-01 00:00:00
abstract:OBJECTIVE:Magnetic resonance imaging has proven to be a useful diagnostic tool for the evaluation of various types of vascular rings and congenital heart disease. We report two cases showing the accuracy of MRI in detecting post-surgical complications in patients with these conditions. MATERIALS AND METHODS:The two ca...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/00004728-199401000-00008
更新日期:1994-01-01 00:00:00
abstract::Computed tomography has had an increasing role in the evaluation of patients after blunt trauma. Important findings in thoracic trauma include acute traumatic aortic injury, pneumothorax, hemothorax, pulmonary contusions and lacerations, mediastinal hematoma, and diaphragmatic rupture. The solid abdominal viscera may ...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章,评审
doi:10.1097/01.rct.0000120858.80935.59
更新日期:2004-07-01 00:00:00
abstract::Despite increasing performance of pituitary imaging, adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas are often difficult to identify because of their small size and variable location. We present a case of ACTH-dependent Cushing syndrome in which the demonstration of the cavernous sinus localization of ...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章,评审
doi:10.1097/00004728-200305000-00021
更新日期:2003-05-01 00:00:00
abstract:PURPOSE:The goal of this study was to evaluate a newly developed semiautomated contour detection algorithm for the quantitative analysis of cardiovascular MRI. METHOD:Left ventricular function parameters derived from automatically detected endocardial and epicardial contours were compared with results derived from man...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/00004728-199709000-00019
更新日期:1997-09-01 00:00:00
abstract::The CT findings in hepatic involvement by Echinococcus granulosus are described. Pathognomonic signs of the hydatid nature of a cystic lesion are visualization of the cystic wall on plain CT, calcification of the cyst wall, daughter cysts, and membrane detachment. ...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/00004728-198410000-00005
更新日期:1984-10-01 00:00:00
abstract:OBJECTIVE:This cross-sectional study assessed the prognostic implications of computed tomography (CT) coronary artery calcification (CAC), independent of emphysema, in patients with chronic obstructive pulmonary disease (COPD). MATERIALS AND METHODS:Coronary artery calcification and emphysema were assessed on noncontr...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/RCT.0000000000000119
更新日期:2014-09-01 00:00:00
abstract:OBJECTIVES:As an application of the computer-aided diagnosis of solitary pulmonary nodules (SPNs), 3-dimensional contrast-enhanced (CE) dynamic helical computed tomography (HCT) was performed to evaluate temporal changes in the internal structure of nodules to differentiate between benign nodules (BNs) and malignant no...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/01.rct.0000155668.28514.01
更新日期:2005-03-01 00:00:00
abstract:PURPOSE:Our goal was to validate linear and nonlinear intersubject image registration using an automated method (AIR 3.0) based on voxel intensity. METHOD:PET and MRI data from 22 normal subjects were registered to corresponding averaged PET or MRI brain atlases using several specific linear and nonlinear spatial tran...
journal_title:Journal of computer assisted tomography
pub_type: 临床试验,杂志文章
doi:10.1097/00004728-199801000-00028
更新日期:1998-01-01 00:00:00
abstract::Present popular computed tomography (CT) algorithms reconstruct an object from the ray measurements lying on a set of parallel planes. This paper presents an algorithm that can also utilize "cross-plane" rays (i.e., rays that cross through many planes) to reconstruct the object. In this reconstruction algorithm, the r...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/00004728-197906000-00015
更新日期:1979-06-01 00:00:00
abstract:OBJECTIVE:To describe the computed tomography (CT) and magnetic resonance imaging (MRI) findings of solid organizing hepatic abscesses and correlate them with the pathologic findings. METHODS:Ten patients with 10 pathologically proven solid organizing hepatic abscesses who underwent 3-phase CT (n = 10) or MRI (n = 7) ...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/00004728-200603000-00004
更新日期:2006-03-01 00:00:00
abstract:PURPOSE:To retrospectively investigate the effect of the section thickness used for quantifying dual-energy perfusion computed tomography (DEpCT) during 2- and 3-dimensional evaluation. METHODS:Sixty-six patients (22 males and 44 females; mean age, 59.3 years) suspected of having an acute pulmonary embolism underwent ...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/RCT.0000000000000148
更新日期:2014-11-01 00:00:00
abstract:OBJECTIVE:To investigate the effect of iodinated contrast medium on sulcal hyperintensity on fluid-attenuated inversion recovery (FLAIR) imaging immediately after intra-arterial thrombolysis in patients with acute ischemic stroke and to determine whether it may be associated with subsequent hemorrhagic transformation (...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/01.rct.0000155669.05643.49
更新日期:2005-03-01 00:00:00
abstract::We present a case of a clinically suspected cerebral infarction that was diagnosed as a seizure focus on pulsed arterial spin labeling. The finding of hyperperfusion with perfusion imaging significantly impacted clinical management of the patient. ...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/RCT.0b013e31814cf81f
更新日期:2008-03-01 00:00:00
abstract:OBJECTIVE:To capture 3D shape variation of the levator ani during straining with open access MR imaging. METHODS:Optimal scan-planning based on statistical shape modeling is developed for recovering the entire 3D structure of the levator ani from a limited number of 2D imaging planes. Statistical shape modeling ensure...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/01.rct.0000155076.42784.ed
更新日期:2005-03-01 00:00:00
abstract:OBJECTIVE:The objective of this study was to compare the accuracy of 320-row computed tomography angiography (CTA) with conventional coronary angiography. METHODS:Two hundred seventy-four patients with coronary artery disease who received both invasive coronary angiography and 320-row CTA were included. Stenosis of 50...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/RCT.0b013e31826ab24a
更新日期:2012-11-01 00:00:00
abstract::Ten consecutive patients with surgically proven beta-islet cell tumors, strongly suspected clinically because of positive laboratory findings, were studied by MRI at 0.5 T. Results were correlated with CT and angiography. MRI detected all 10 insulinomas, with the location confirmed at surgery. Lesion size was < 1 cm i...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/00004728-199305000-00012
更新日期:1993-05-01 00:00:00
abstract::In vivo attenuation values of 19 fluid collections in 17 patients were compared with in vitro values obtained on examination of the aspirated fluids within the calibration phantom of an EMI CT5005 body scanner. While the in vitro values showed a 5.2 Hounsfield unit (HU:1,000 scale). difference between cysts and absces...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/00004728-198004000-00002
更新日期:1980-04-01 00:00:00
abstract::Implementation of an accurate, reliable index of cost effectiveness would help to advance technology assessment and reimbursement of MR imaging procedures, including gadolinium enhancement. To this end, an objective, consensual measure that satisfies the need for "gold-standard" confirmation of diagnostic impressions ...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/00004728-199301001-00008
更新日期:1993-01-01 00:00:00
abstract:OBJECTIVE:This study aimed to determine optimal strength of sinogram-affirmed iterative reconstruction (SAFIRE) and to evaluate image quality (IQ) of low-dose chest computed tomography (LDCT) using SAFIRE compared with iterative reconstruction in image space (IRIS) and filtered back projection (FBP). METHODS:Thirty pa...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/RCT.0b013e31828f4dae
更新日期:2013-07-01 00:00:00
abstract::A soft tissue mass close to the upper pole of the left kidney was noted in a patient referred for intravenous pyelography. A left adrenal tumor was suspected. Computed tomography, however, revealed an accessory spleen. The diagnosis was confirmed by abdominal angiography. ...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/00004728-198008000-00028
更新日期:1980-08-01 00:00:00
abstract:OBJECTIVES:The aim of this study is to evaluate the effect of heart rate on exposure window, best phase, and image quality for stress computed tomography perfusion (CTP) in the CORE320 study. METHODS:The CTP data sets were analyzed to determine the best phase for perfusion analysis. A predefined exposure window coveri...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章,多中心研究
doi:10.1097/RCT.0000000000000514
更新日期:2017-03-01 00:00:00
abstract:PURPOSE:Our goal was to assess the utility of different imaging directions in volumetric studies of the heart with MRI, in particular to identify the optimal imaging plane for studies of the right ventricle. METHOD:We examined 12 sets of human four-chamber cadaveric cardiac casts. Gradient echo MRI was performed in fo...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/00004728-199811000-00012
更新日期:1998-11-01 00:00:00
abstract:BACKGROUND:Neonatal hypoxic-ischemic encephalopathy (HIE) is associated with dysfunctional cerebral autoregulation. Resistive index (RI) measured in the anterior cerebral artery on transfontanellar head ultrasound is a noninvasive measure of blood flow and may indicate autoregulation dysfunction. We tested whether RI w...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/RCT.0000000000001069
更新日期:2020-09-01 00:00:00
abstract:PURPOSE:The purpose of this work was to evaluate the helical CT and CT angiography (CTA) findings of anomalous systemic artery (ASA) to the basal segments of the left lower lobe (LLL). METHOD:Three patients (two had hemoptysis, one was asymptomatic) with blotchy nodular density in the LLL revealed on chest radiographs...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章
doi:10.1097/00004728-200011000-00026
更新日期:2000-11-01 00:00:00
abstract::The purpose of this 4-part series is to illustrate the nuances of temporal bone anatomy using a high-resolution (200-mu isotropic) prototype volume computed tomography (CT) scanner. The normal anatomy in axial and coronal sections is depicted in the first and second parts. In this and the subsequent part, the structur...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章,评审
doi:10.1097/00004728-200603000-00034
更新日期:2006-03-01 00:00:00
abstract:OBJECTIVE:To evaluate the distal extent and attenuation of bowel opacification achieved after administration of a single low volume dose of oral contrast 2 hours before computed tomographic colonography (CTC) after incomplete optical colonoscopy. METHODS:This retrospective study included 144 patients undergoing CTC af...
journal_title:Journal of computer assisted tomography
pub_type: 杂志文章,多中心研究
doi:10.1097/RCT.0b013e3181f5a610
更新日期:2011-01-01 00:00:00