Intraindividual variation of dose parameters in oncologic CT imaging.

The objective of this study is to identify essential aspects influencing radiation dose in computed tomography [CT] of the chest, abdomen and pelvis by intraindividual comparison of imaging parameters and patient related factors. All patients receiving at least two consecutive CT examinations for tumor staging or follow-up within a period of 22 months were included in this retrospective study. Different CT dose estimates (computed tomography dose index [CTDIvol], dose length product [DLP], size-specific dose estimate [SSDE]) were correlated with patient's body mass index [BMI], scan length and technical parameters (tube current, tube voltage, pitch, noise level, level of iterative reconstruction).

A ten-year, single-center experience: Concordance between breast core needle biopsy/vacuum-assisted biopsy and postoperative histopathology in B3 and B5a cases.

Purpose: To determine the concordance rate between core needle biopsy/vacuum-assisted biopsy (CNB/VAB) and postoperative histopathology in B3 (lesions of uncertain malignant potential) and B5a (in situ) lesions found on mammograms or ultrasound.

Material And Methods: 2,029 consecutive biopsies performed over 10 years for patients who underwent mammograms or ultrasounds. For CNB 14G needle and for VAB 8G/10G needles were used.

Experimental Evaluation of the Heat Sink Effect in Hepatic Microwave Ablation.

Purpose: To demonstrate and quantify the heat sink effect in hepatic microwave ablation (MWA) in a standardized ex vivo model, and to analyze the influence of vessel distance and blood flow on lesion volume and shape.

Materials And Methods: 108 ex vivo MWA procedures were performed in freshly harvested pig livers. Antennas were inserted parallel to non-perfused and perfused (700,1400 ml/min) glass tubes (diameter 5mm) at different distances (10, 15, 20mm).

Functional gadoxetate disodium-enhanced MRI in patients with primary sclerosing cholangitis (PSC).

Objectives: To assess the value of variable flip angle-based T1 liver mapping on gadoxetate disodium-enhanced MRI in patients with primary sclerosing cholangitis (PSC) for evaluation of global and segmental liver function, and determine a possible correlation with disease severity.

Methods: Sixty-one patients (19 female, 42 male; mean age 41 years) with PSC were included in this prospective study. T1 mapping was performed using a 3D-spoiled GRE sequence (flip angles 5°, 15°, 20°, 30°) before, 16 (HP1) and 132 min (HP2) after contrast injection.

Value of oral effervescent powder administration for multidetector CT evaluation of esophageal cancer.

Purpose: To assess the value of oral effervescent powder (EP) for evaluation of esophageal distension, and for detection and staging of esophageal cancer with contrast-enhanced CT.

Materials And Methods: 84 patients without esophageal pathology and 52 patients with histological confirmed diagnosis of esophageal cancer were included in this prospective IRB-approved study. Half of the patients in both groups received EP prior to CT.

Non-invasive quantification of anti-angiogenic therapy by contrast-enhanced MRI in experimental pancreatic cancer.

Background: Currently, early changes of tumor vasculature after angiogenesis inhibition can only be evaluated by histopathology, a method not suitable in a clinical setting.

Purpose: To quantify effects of different angiogenesis inhibitors on the microvasculature of orthotopically implanted pancreatic cancers by contrast-enhanced magnetic resonance imaging (MRI) in order to establish a non-invasive technique for monitoring antiangiogenic cancer treatment.

Material And Methods: DSL-6A/C1 pancreatic cancers were implanted in the pancreas of 109 Lewis rats.

Permeability to macromolecular contrast media quantified by dynamic MRI correlates with tumor tissue assays of vascular endothelial growth factor (VEGF).

Purpose: To correlate dynamic MRI assays of macromolecular endothelial permeability with microscopic area-density measurements of vascular endothelial growth factor (VEGF) in tumors.

Methods And Material: This study compared tumor xenografts from two different human cancer cell lines, MDA-MB-231 tumors (n=5), and MDA-MB-435 (n=8), reported to express respectively higher and lower levels of VEGF. Dynamic MRI was enhanced by a prototype macromolecular contrast medium (MMCM), albumin-(Gd-DTPA)35.

Correlative dynamic contrast MRI and microscopic assessments of tumor vascularity in RIP-Tag2 transgenic mice.

The purpose of this study was to define the feasibility of dynamic contrast-enhanced magnetic resonance imaging (MRI) to estimate the vascular density and leakiness of spontaneous islet cell tumors in RIP-Tag2 transgenic mice. Dynamic T(1)-weighted spoiled gradient echo (SPGR) imaging at 2.0 T was performed in 17 RIP-Tag2 mice using a prototype blood pool macromolecular contrast medium (MMCM), albumin-(Gd-DTPA)(35).

In vivo monitoring of angiogenesis inhibitory treatment effects by dynamic contrast-enhanced computed tomography in a xenograft tumor model.

Rationale And Objectives: To evaluate the potential of dynamic CT enhanced by iohexol or a novel macromolecular contrast agent, PEG12000-Gen4-triiodo, to monitor microvascular changes in tumors treated with the angiogenesis inhibitor bevacizumab.

Materials And Methods: Ten female nude rats with MDA-MB 435 xenograft tumors were treated with 1 mg intraperitoneal bevacizumab when tumors reached 1 cm diameter and, for 4 rats, treated again 7 days later. Just before and 24 hours after the first injection of anti-VEGF antibody, the tumors were imaged by dynamic CT scans enhanced with PEG12000-Gen4-triiodo (n = 3 rats) or iohexol (n = 3 rats).

Vascular permeability during antiangiogenesis treatment: MR imaging assay results as biomarker for subsequent tumor growth in rats.

Purpose: To prospectively evaluate in rats the acute change in tumor vascular leakiness (K(PS)) assayed at magnetic resonance (MR) imaging after a single dose of the angiogenesis inhibitor bevacizumab as a predictive biomarker of tumor growth response after a prolonged treatment course.

Materials And Methods: Institutional animal care and use committee approval was obtained. Seventeen female rats with implanted human breast cancers underwent dynamic albumin-(Gd-DTPA)(30)-enhanced MR imaging followed by an initial dose of bevacizumab or saline (as a control).

New macromolecular polymeric MRI contrast agents for application in the differentiation of cancer from benign soft tissues.

Purpose: To compare three new macromolecular polyethylene glycol (PEG) -core dendrimeric gadolinium(Gd)-based MRI contrast agents for their applicability in quantitative assays of endothelial leakiness and tissue vascular density for the differentiation of cancer from normal soft tissues.

Materials And Methods: Thirty-two athymic rats with human breast cancer xenografts (MDA-MB-435) were imaged by dynamic MRI following enhancement with one of three new (Gd-DOTA)-conjugated PEG-core dendrimer contrast agents (effective molecular weights 161 to 323 kDa). Results were compared with a prototype macromolecular contrast agent, albumin (Gd-DTPA).

Cascade polymeric MRI contrast media derived from poly(ethylene glycol) cores: initial syntheses and characterizations.

Diagnostic contrast media for magnetic resonance imaging (MRI) are often applied to enhance the signal of blood allowing for quantitative definition of vascular functional characteristics including tissue blood volume, flow, and leakiness. Well-tolerated and safe macromolecular formulations are currently being sought that remain in the blood for a relatively long period and that leak selectively from diseased vessels, particularly cancer vessels. We synthesized a new class of macromolecular, water-soluble MRI contrast media by introducing two diverging polylysine cascade amplifiers at each end of a poly(ethylene glycol) (PEG) backbone, followed by substitution of terminal lysine amino groups with Gd-DTPA chelates.

MR imaging of antigen-induced arthritis with a new, folate receptor-targeted contrast agent.

The purpose of this study was to investigate if the new folate receptor-targeted Gd-chelate P866 may enhance immune-mediated arthritis. A monoarthritis was induced in the right knee of 15 Sprague-Dawley rats. MR imaging of both knees was performed at 2 T before and up to 2 h and 24 h after injection (p.

Magnetic resonance imaging enhancement of normal tissues and tumors using macromolecular Gd-based cascade polymer contrast agents: preclinical evaluations.

Objectives: We sought to compare magnetic resonance imaging (MRI) enhancement using 4 novel macromolecular polyethyleneglycol (PEG)-based cascade-polymer gadolinium contrast agents (macromolecular contrast media) in normal soft tissues and a breast cancer model.

Materials And Methods: Four candidate PEG cascade polymers with effective molecular weights of 74, 82, 106, and 132 kDa, respectively, and T1-relaxivities of 8.1, 9.

Dendritic iodinated contrast agents with PEG-cores for CT imaging: synthesis and preliminary characterization.

The purpose of this study was to design, synthesize, and initially characterize a representative set of novel constructs for large-molecular radiographic/computed tomography (CT) contrast agents, intended for a primarily intravascular distribution. A new assembly of well-known and biocompatible components consists of paired, symmetrical dendritic polylysines initiated from both ends of a poly(ethylene glycol) (PEG) core, yielding an array of multiple free amino groups to which were conjugated highly soluble and stable triiodophthalamide ("triiodo") moieties. An array of six dendritic contrast agents was synthesized originally, using three different PEG cores (3, 6, 12 kDa) with t-Boc lysine-generated dendrimer "amplifiers" (from three to five generations) containing 16 to 64 amino groups for conjugation with reactive triiodo moieties.

Ultrasmall superparamagnetic iron-oxide-enhanced MR imaging of normal bone marrow in rodents: original research original research.

Rationale And Objectives: The objective is to compare three different ultrasmall superparamagnetic iron oxides (USPIOs) for magnetic resonance (MR) imaging of normal bone marrow in rodents.

Materials And Methods: Femoral bone marrow in 18 Sprague-Dawley rats was examined by using MR imaging before and up to 2 and 24 hours postinjection (PI) of 200 mumol of Fe/kg of SHU555C (n = 6), ferumoxtran-10 (n = 6), or ferumoxytol (n = 6), using T1-weighted (50 ms/1.7 ms/60 degrees = repetition time [TR]/echo time [TE]/flip angle) and T2*-weighted (100 ms/15 ms/38 degrees = TR/TE/flip angle) three-dimensional spoiled gradient recalled echo sequences.