Abstract:
:The potential of magnetic resonance imaging (MRI) quantification of calcium for the evaluation of pulmonary nodules was investigated in simulated nodules. Calcium salts do not contain mobile protons and thus have no signal on MR proton images. To determine whether the absence of signal from partially calcified nodules could be quantified, we studied simulated nodules containing known quantities of calcium salts. The soft tissue equivalent material was an agar-gelatin mixture (T1:1100-1500 msec; T2: 59-62 msec). In the first experiments, glass tubes were filled with the mixture, which contained suspensions of calcium carbonate (CaCO3) or silica dioxide (Si02), and were subjected to computed tomography (CT) scanning and MR imaging. In a second series of studies CaCO3 particles of various sizes (and therefore different surface-to-volume ratios) were similarly suspended and subjected to CT scanning and MR imaging. In a third series hydroxyapatite (HA) suspensions of different sizes were similarly studied. CaCO3 produced a significant reduction in MR hydrogen density and signal intensity of the agar-gelatin mixture. Reduction in T1 and T2 relaxation times was inconsistent and not related to particle size. CaCO3 produced its effect by soft-tissue displacement. HA (and Si02) caused a more marked fall in MR hydrogen density, signal intensity, and T1 and T2 relaxation times. The degree of the T1 and T2 effects was related to particle size, indicating a hydrophilic surface effect. The authors conclude that MRI quantification of calcium within pulmonary nodules (or other tissues) will be complex and will relate to the precise composition of the calcium salt and to the particle size of the aggregates.
journal_name
Invest Radioljournal_title
Investigative radiologyauthors
Gamsu G,de Geer G,Cann C,Müller N,Brito Adoi
10.1097/00004424-198711000-00001subject
Has Abstractpub_date
1987-11-01 00:00:00pages
853-8issue
11eissn
0020-9996issn
1536-0210journal_volume
22pub_type
杂志文章abstract:OBJECTIVES:To test the technique and feasibility of translating tumor suspicious region maps in the prostate, obtained by multimodality, anatomic, and functional 3T magnetic resonance imaging (MRI) data to 32-channel coil, T2-weighted (T2-w), 3T MR images, for directing MR-guided biopsies. Furthermore, to evaluate the ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0b013e31817d0506
更新日期:2008-10-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:To evaluate the efficacy of oral administration of cilostazol, an antithrombotic agent, for the prevention of thrombotic occlusion and intimal hyperplasia after stenting. METHODS:Single-bodied Z-stents were placed in the iliac arteries of 23 dogs. Before stenting, an embolizing coil was introd...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199509000-00004
更新日期:1995-09-01 00:00:00
abstract::Three methods are presented which provide statistically acceptable estimates of mean transit time of opacified blood during angiography. While the methods vary in precision, the selection of the method appropriate for any particular experimental model depends on the degree of precision required to demonstrate the effe...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-197707000-00004
更新日期:1977-07-01 00:00:00
abstract:OBJECTIVES:Over the recent years, there have been increasing concerns that exposure to gadolinium-based contrast agents (GBCAs) may be associated with retention of Gd within the skin, bones, and solid organs in patients with normal renal function, although the clinical implications of this deposition remain to be estab...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000657
更新日期:2020-07-01 00:00:00
abstract:OBJECTIVES:To evaluate the potential of quantitative assays of vascular characteristics based on dynamic contrast-enhanced magnetic resonance imaging (MRI) using a macromolecular contrast medium (MMCM) to search for and measure effects of dimethyl sulfoxide (DMSO) on cancer vasculature with microscopic correlations. M...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0b013e318164b71d
更新日期:2008-05-01 00:00:00
abstract::Screening chronic hemodialysis patients (CHD) for acquired cystic disease of the kidneys (ACDK) and its complications (hemorrhage and neoplasm) has become accepted management. We evaluated patients on CHD as well as patients on chronic peritoneal dialysis (CPD) for ACDK. The kidneys of 80 chronic dialysis patients wer...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:
更新日期:1987-09-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:The authors studied the effect of contrast dose, use of magnetization transfer (MT), and temporal delay on the visualization of contrast enhancement with gadoteridol (Gd HP-DO3A) in a canine brain abscess model. METHODS:Alpha streptococcus brain abscesses were studied in five dogs at 1.5 tesla...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199503000-00001
更新日期:1995-03-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:To evaluate the short-term effects of a new nitinol stent on canine arteries. METHODS:Eighteen nitinol mesh stents were placed in abdominal aortas, common iliac arteries, and renal arteries of six dogs. Angiography was performed to evaluate the patency rates and structural changes of arteries ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199905000-00007
更新日期:1999-05-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:Measurements of segmental contraction of the left ventricle by standard magnetic resonance imaging (MRI) and two-dimensional echocardiography involve the comparison of diastolic and systolic time frames acquired from the same imaging plane in space. As the cone-shaped left ventricle shortens al...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199209000-00004
更新日期:1992-09-01 00:00:00
abstract::Gallbladder sclerotherapy after permanent cystic duct occlusion, to prevent gallstone recurrence in nonsurgical gallstone therapy, is at least a two-stage procedure. A balloon catheter was developed to perform gallbladder sclerotherapy with only temporary occlusion of the cystic duct, and the efficacy and safety of th...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199109000-00005
更新日期:1991-09-01 00:00:00
abstract:OBJECTIVES:The aim of this work was to quantitatively evaluate the pharmacokinetic pattern of Gd-EOB-DTPA in a model of isolated and perfused mouse liver by using magnetic resonance imaging (MRI) and monochromatic quantitative computed tomography (MQCT). MATERIALS AND METHODS:For MQCT, perfusions were realized with th...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/01.rli.0000174474.43772.58
更新日期:2005-09-01 00:00:00
abstract:OBJECTIVES:The aim of this study was to investigate blood pressure dependency of ultrasound time-harmonic elastography (THE) for quantification of aortic stiffness. MATERIALS AND METHODS:Thoracoabdominal aortas were surgically removed from 9 healthy domestic pigs and prepared for elastographic experiments. All vessels...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000618
更新日期:2020-03-01 00:00:00
abstract:INTRODUCTION:Attenuation correction for magnetic resonance (MR) coils is a new challenge that came about with the development of combined MR and positron emission tomography (PET) imaging. This task is difficult because such coils are not directly visible on either PET or MR acquisitions with current combined scanners ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0b013e3182a530f8
更新日期:2014-02-01 00:00:00
abstract::Capacity-limited elimination of sodium iopanoate and a reproducible apparent transport maximum (Tm) were demonstrated in nonoperated dogs having an intact enterohepatic circulation and normal endogenous bile salt pool. Using a multiple infusion technique, estimation of apparent Tm of iopanoate in the liver was possibl...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-197601000-00007
更新日期:1976-01-01 00:00:00
abstract::Proposed causes of renal papillary necrosis (RPN) include tubular toxicity due to hyperconcentration of toxins in the renal medulla and vasoconstriction of medullary vessels with ischemic necrosis. The authors studied these mechanisms in bromoethylamine hydrobromide-induced RPN in rats by microvascular and tubular mic...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-198103000-00006
更新日期:1981-03-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:To compare electron beam tomography (EBT) with MR imaging (MRI) for detection of restenosis after coronary angioplasty (PTCA). METHODS:One hundred eighteen patients after PTCA were investigated. By EBT, 50 axial images were acquired (3-mm slice thickness, 120-160 mL radiographic contrast agent...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-200207000-00005
更新日期:2002-07-01 00:00:00
abstract::We evaluated the density distribution (anterior-posterior) of the right lung in 19 acutely anesthetized supine dogs using computed transmission tomography (CTT). Eleven dogs served as controls, and eight received 0.12 cc/kg of intravenously administered oleic acid. The latter were sequentially imaged over 1 hour. Nine...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:
更新日期:1984-05-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:Our purpose was to validate contrast-enhanced computed tomography (CECT)-derived quantitative measures of perfusion and permeability against gold standard techniques of fluorescent microspheres and Evan's Blue dye, respectively. MATERIALS AND METHODS:Normal and tumor-bearing (R3230AC) Fischer ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/01rli.0000124456.82985.35
更新日期:2004-06-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:To compare technical aspects and neointima formation of a new Nitinol stent and a Wallstent. METHODS:A Nitinol sten and a Wallstent were placed into the iliac arteries of 14 sheep (total of 28 stents) and followed angiographically. Seven sheep were killed after 1 month and 7 after 4.5 months. ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199507000-00004
更新日期:1995-07-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:Tools for monitoring modern target-specific antiangiogenic and antivascular therapies are highly desirable because treatment strategies are time consuming, expensive, and yet sometimes ineffective. Therefore, the aim of this experimental study was to evaluate the predictive value of steady-stat...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0b013e3180d5cbd9
更新日期:2007-12-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:To demonstrate the usefulness of a model of the parenchymous vascularization to evaluate texture analysis methods. METHODS:Slices with thickness varying from 1 to 4 mm were reformatted from a 3D vascular model corresponding to either normal tissue perfusion or local hypervascularization. Param...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199903000-00004
更新日期:1999-03-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:Iopromide is a new monomeric, nonionic contrast agent that exhibits low osmolality and low viscosity in high concentration in aqueous solutions. Double-blind, randomized clinical trials have established the efficacy, safety, and tolerance of iopromide for excretory urography, coronary angiograp...
journal_title:Investigative radiology
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1097/00004424-199405001-00015
更新日期:1994-05-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:Hepatocellular carcinomas (HCCs) usually consist of components of different histologic grade. Using surgically resected specimens, the authors obtained high-resolution magnetic resonance (MR) images and studied the relationship between histologic grade of HCCs and MR signal intensity. METHOD:I...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199308000-00007
更新日期:1993-08-01 00:00:00
abstract:RATIONAL AND OBJECTIVES:The purpose of this study was to evaluate the effects of variation in design parameters on the resultant radial force. We evaluated the influence of wire gauge, leg length, and number of bends on the radial force produced by z stents and compared these with radial forces produced by commercial s...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-200109000-00004
更新日期:2001-09-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:The authors determine the value of contrast-enhanced, three-dimensional (3D) magnetic resonance angiography (MRA) in the assessment of the renal arteries in comparison with conventional arteriography (CA). METHODS:One hundred three patients (71 m, 32 f) were evaluated with both CA and 3D MRA. ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199809000-00021
更新日期:1998-09-01 00:00:00
abstract:PURPOSE:To determine whether time-resolved magnetic resonance angiography (TR-MRA) with ultra-low-dose gadolinium chelate (1.5-3.0 mL) can reliably detect or rule out hemodynamically significant disease in the carotid-vertebral artery territory. MATERIALS AND METHODS:Hundred consecutive patients (62 women, 38 men, mea...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0b013e31819ca048
更新日期:2009-04-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:To develop a new animal model for the evaluation of the renal tolerance of contrast agent and its application to diatrizoate and iotrolan injections in comparison to saline and mannitol solution. MATERIALS AND METHODS:The nephrotoxic potential of intravenously injected contrast agents in Beagl...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/01.rli.0000087096.61127.13
更新日期:2003-11-01 00:00:00
abstract::Maximum likelihood estimation, assuming a binormal model, has been used extensively to estimate the area under receiver operating characteristic (ROC) curves and thus provide an index of diagnostic accuracy for the comparison of two imaging systems. However, in some instances, a degenerate data set results in a fitted...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199007000-00016
更新日期:1990-07-01 00:00:00
abstract::The importance of evaluating medical student performance has been widely addressed in the medical education literature. Multiple-choice examinations are the preferred method of testing because they are easy to administer and score. Development of parallel or equivalent pre- and post-examinations provides objective inf...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:
更新日期:1986-09-01 00:00:00
abstract:OBJECTIVES:The aim of this study was to investigate the feasibility of kidney stone composition analysis using spectral detector computed tomography scanner (SDCT) with normal- and low-dose imaging protocols. METHODS:A total of 154 stones harvested from nephrolithotripsy or nephrolithotomy with a known monocrystalline...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000468
更新日期:2018-08-01 00:00:00