Poly(ethylene glycol)-coated anti-cardiac myosin immunoliposomes: factors influencing targeted accumulation in the infarcted myocardium.

Biodistribution and infarct accumulation of different liposome preparations in rabbits with experimental myocardial infarction have been investigated. The influence of such parameters as liposome size, and presence or absence of poly(ethylene glycol) (PEG) and infarct-specific antimyosin antibody (AM) on liposome behavior in vivo was studied. All three variables were shown to affect liposome biodistribution, liposome size being the least significant variable.

Continuous assessment of relative cerebral blood volume in transient ischemia using steady state susceptibility-contrast MRI.

The utility of a noninvasive steady state susceptibility-contrast MRI technique for continuous measurement of relative cerebral blood volume (rCBV) during global transient ischemia and subsequent hyperemia in a feline ischemia model is demonstrated. The measurements were obtained during a 10-min period of occlusion and 1-h period of reperfusion. Maximal hyperemic responses in gray matter, basal ganglia, and white matter (observed at 7,7, and 5 min, respectively) were 1.

Preoperative staging of cancer of the pancreas: value of MR angiography versus conventional angiography in detecting portal venous invasion.

Objective: The purpose of this study was to compare contrast-enhanced MR angiography with conventional catheter angiography for detecting portal venous invasion in the preoperative staging of pancreatic cancer, using the surgical confirmation of vascular involvement as the standard of truth.

Subjects And Methods: MR and conventional angiography were performed in 20 patients with pancreatic carcinoma, with surgical confirmation in all cases. MR angiography was performed at 1.

Secondary elevation of extracellular neurotransmitter amino acids in the reperfusion phase following focal cerebral ischemia.

The purpose of this study was to evaluate amino acid neurotransmitter dynamics in the reperfusion phase after transient cerebral ischemia. In vivo microdialysis was used to measure extracellular amino acid levels in a rabbit model of focal ischemia. During 30 min of transient ischemia (n = 5), small but significant (p < 0.

Normal interval fetal growth rates based on obstetrical ultrasonographic measurements.

Analyzing fetal interval growth may improve detection of growth abnormalities. This study establishes normal limits for growth rates of fetal biparietal diameter, abdominal diameter, abdominal circumference, and femur length. Fetal measurements were obtained during 1450 obstetrical sonographic examinations in 510 patients with normal-weight term deliveries.

Functional MR in the evaluation of dementia: correlation of abnormal dynamic cerebral blood volume measurements with changes in cerebral metabolism on positron emission tomography with fludeoxyglucose F 18.

Purpose: To determine whether magnetic susceptibility functional MR imaging of cerebral blood volumes provides information similar to fludeoxyglucose F 18 positron emission tomography (PET) brain images in patients undergoing evaluation for dementia.

Methods: Ten subjects were studied with both PET and functional MR. Clinical diagnoses included probable Alzheimer disease (n = 5), possible Alzheimer disease (n = 1), Pick disease (n = 2), and primary progressive aphasia (n = 2).

Normal renal artery spectral Doppler waveform: a closer look.

Purpose: To characterize the spectral Doppler tracing of the normal renal artery.

Materials And Methods: Doppler tracings were obtained from a phantom of a vessel with variable compliance and from the kidneys of 15 healthy volunteers.

Results: In the phantom, vascular compliance had the following effects on systolic flow velocity patterns: low compliance, little change in the sharp appearance of the systolic component of the transmitted pulse; mildly increased compliance, down-stream dampening of early systolic acceleration (ESA) with the appearance of a sharp early systolic transmitted peak and of a more rounded late systolic compliance peak; high compliance, delayed and diminished transmitted peak that eventually disappeared within the enlarging down-stream compliance peak.

Hepatic imaging with iodinated nanoparticles: a comparison with iohexol in rabbits.

Rationale And Objectives: We evaluated the efficacy of a particulate computed tomography (CT) contrast agent in an animal model of focal liver disease.

Methods: Ethyl ester of diatrizoic acid (EEDA) is an iodinated (89 mg I/ml) nanoparticulate (200 nm) contrast agent intended for intravenous use that is currently undergoing preclinical testing in our laboratory. Focal liver abscesses were created in 11 New Zealand White rabbits.

Threshold selection for CT angiography shaded surface display of the renal arteries.

The purpose of this study was to define objective criteria to calculate a tissue segmentation threshold for shaded surface display (SSD) rendering of the renal arteries with computed tomography angiography. Contrast-enhanced spiral CT scans were obtained through the renal arteries of nine patients. Six sets of SSD images were rendered for each patient with lower threshold values ranging from 80 to 130 Hounsfield units (HU) by increments of 10 HU.

Superior hypogastric plexus block for chronic pelvic pain in the presence of endometriosis: CT techniques and results.

Purpose: To evaluate the use of superior hypogastric plexus block with computed tomographic (CT) guidance in patients with endometriosis and chronic pelvic pain.

Materials And Methods: Seven blocks were performed on an outpatient basis in five women with endometriosis and pelvic pain. In the first four patients, one or two 20-gauge, 15-cm needles were placed anterior to the spine at the common iliac bifurcation from a posterior approach.

Renal artery stenosis: should we study the main renal artery or segmental vessels?

Purpose: To compare the sonographic diagnosis of renal artery stenosis (RAS) with Doppler interrogation of the main renal artery versus Doppler ultrasonography of segmental vessels.

Materials And Methods: The main renal artery-to-aortic peak systolic velocity ratio (RAR) and early systolic acceleration in segmental arteries were obtained in 186 patients. Conventional arteriographic correlation was available for 42 kidneys in 21 patients.

The association of paracardial adenopathy with hepatic metastasis found on CT arterial portography.

Background: The association of paracardial lymphadenopathy with hepatic metastases in patients undergoing computed tomographic arterial portography (CTAP) prior to possible resection of hepatic metastases is documented.

Methods: CTAP was performed on 45 patients with hepatic metastasis, including 30 with colorectal carcinoma, using 1 cm increments from the dome of the diaphragm through the liver. Two radiologists, blinded to the diagnosis and surgical results, reviewed all portograms and identified all paracardial lymph nodes larger than 8 cm.

A test pattern for quality control of laser scanner and charge-coupled device film digitizers.

Although clinical images provide the ultimate test of diagnostic performance for a film digitizer, such images are not generally suitable for daily quality control (QC) purposes. However, a well-designed test pattern will provide a rapid, comprehensive, objective and reproducible assessment of image quality. This pattern should evaluate various parameters of image quality, including high contrast resolution, low contrast discrimination, linearity of gray scale, geometric distortion, and noise.

Nephrotoxicity of ionic and nonionic contrast media in 1196 patients: a randomized trial. The Iohexol Cooperative Study.

The incidence of nephrotoxicity occurring with the nonionic contrast agent, iohexol, and the ionic contrast agent, meglumine/sodium diatrizoate, was compared in 1196 patients undergoing cardiac angiography in a prospective, randomized, double-blind multicenter trial. Patients were stratified into four groups: renal insufficiency (RI), diabetes mellitus (DM) both absent (N = 364); RI absent, DM present (N = 318); RI present, DM absent (N = 298); and RI and DM both present (N = 216). Serum creatinine levels were measured at -18 to 24, 0, and 24, 48, and 72 hours following contrast administration.

Nanoparticulate computed tomography contrast agents for blood pool and liver-spleen imaging.

Rationale And Objectives: We investigated the properties of a group of iodine-containing, insoluble compounds formulated as nanoparticles for use as potential blood pool and liver-spleen contrast agents.

Methods: High-resolution, quantitative computed tomography (CT) was performed prior to and at intervals following the intravenous administration of the contrast agents to rabbits. Time-density characteristics for three organs were evaluated.

Time-lapse quantitative computed tomography lymphography: assessing lymphatic function in vivo.

Rationale And Objectives: Immobility and massage produce different local limb lymph flow rates. We studied their influence on accumulation of radiopaque nanoparticulates in regional lymph nodes of normal rabbits.

Methods: Quantitative lymphography at 10-min intervals was used to follow the transport of subcutaneous (s.

Sonographic evaluation of fetal growth: growth rate variability as a function of the interval between examinations.

Objective: Fetal growth rates determined on the basis of findings at two separate sonographic examinations can be used to detect growth abnormalities. This article determines the relationship between the length of the interval between examinations and the associated variability in measured fetal growth rates.

Materials And Methods: We analyzed 1479 fetal measurements of the biparietal diameter, average abdominal diameter, and femur length from 539 normal pregnancies.

CT done 4-6 hr after CT arterial portography: value in detecting hepatic tumors and differentiating from other hepatic perfusion defects.

Objective: Nontumorous perfusion defects occur during CT arterial portography (CTAP) as normal variants or in cirrhosis, focal fatty infiltration, and portal vein obstruction. The purpose of this study was to determine whether delayed CT 4-6 hr after CTAP improves sensitivity to hepatic tumors and differentiates them from other hepatic perfusion defects.

Subjects And Methods: CTAP was done at 1-cm increments on 26 patients for evaluation of hepatic tumors.

Inadequacy of sample sizes in clinical trials of laboratory parameters attributable to invalid statistical assumptions.

Clinical trials often determine the sample size based on the use of statistical methods such as analysis of variance, t tests, and rank sum tests, which compare mean or median values. The resulting studies rarely are big enough to show that the method is based on mistaken assumptions. Data from a recent clinical trial of nephrotoxicity associated with the use of contrast agents during angiography found a significant difference on the order of the difference that previous studies had intended to detect.

Application of wavelet compression to digitized radiographs.

Objective: Image data compression is an enabling technology for teleradiology and picture archive and communication systems. Compression decreases the time and cost of image transmission and the requirements for image storage. Wavelets, discovered in 1987, constitute a new compression technique that has been described in radiologic publications but, to our knowledge, no previous studies of its use have been reported.

MR imaging of the liver at 1.5 T: value of signal averaging in suppressing motion artifacts.

Objective: Prior reports have suggested that signal averaging is not as effective as phase reordering for suppressing motion-related artifacts on T1-weighted spin-echo MR imaging of the liver at high field strengths. We hypothesized that with shorter TEs, signal averaging could be effective, and therefore undertook this study to compare signal averaging with phase reordering at 1.5T.