Use Of Contrast-enhanced Imaging Research Articles

Measuring synovial thickness on knee MRI in pediatric patients with arthritis: is contrast necessary?

The use of contrast-enhanced imaging has long been standard for magnetic resonance imaging (MRI) assessments of synovitis in juvenile idiopathic arthritis (JIA). However, advancements in MRI technology have allowed for reliable identification of synovium without contrast. To assess the equivalence of unenhanced MRI with contrast-enhanced MRI in evaluating synovial thickness. This is an institutional review board approved, retrospective study performed in a tertiary children's hospital. Pediatric JIA patients under 21 years old were included who underwent knee MRI scans (1.5 T or 3 T) without and with contrast between January 2012 and January 2022. Two radiologists independently measured synovial thickness at 6 knee sites on contrast-enhanced and unenhanced sequences. Numerical measurements and ordinal scores based on juvenile idiopathic arthritis magnetic resonance imaging scoring (JAMRIS) system were recorded, and tests of equivalence were conducted, as well as between-reader and within-reader reliability by concordance correlation coefficient (CCC). All tests were considered significant at the 5% level. A total of 38 studies from 35 patients (25 females, median age 14 years; interquartile range 7 to 15.7) were included. Equivalence was demonstrated at each of the 6 sites for both continuous measurements (P-values < 0.05) and ordinal scores (P-values < 0.05) based on the average over readers. Within-reader reliability was moderate to high (CCC 0.50-0.89), except for the cruciate ligaments site. Averaged over the 6 sites, reliability between readers was low for unenhanced (CCC 0.47, with 95% CI: [0.41, 0.53]) and moderate for contrast-enhanced (CCC 0.64, with 95% CI: [0.59, 0.69]) sequences. Unenhanced knee MRI is equivalent to contrast-enhanced MRI in assessment of synovial thickness using conventional MRI sequences. Contrast material helped improve inter-reader reliability.

Patient preferences regarding use of contrast-enhanced imaging for breast cancer screening

Our purpose is to understand patient preferences towards contrast-enhanced imaging such as CEM or MRI for breast cancer screening. An anonymous survey was offered to all patients having screening mammography at a single academic institution from December 27 th 2019 to March 6 th 2020. Survey questions related to: (1) patients' background experiences (2) patients' concern for aspects of MRI and CEM measured using a 5-point Likert scale, and (3) financial considerations. 75% (1011/1349) patients completed the survey. 53.0% reported dense breasts and of those, 47.6% had additional screening. 49.6% had experienced a callback, 29.0% had a benign biopsy, and 13.7% had prior CEM/MRI. 34.7% were satisfied with mammography for screening. A majority were neutral or not concerned with radiation exposure, contrast allergy, IV line placement, claustrophobia, and false positive exams. 54.7% were willing to pay at least $250-500 for screening MRI. Those reporting dense breasts were less satisfied with mammography for screening (p<0.001) and willing to pay more for MRI (p<0.001). If patients had prior CEM/MRI, there was less concern for an allergic reaction (p<0.001), IV placement (p=0.025), and claustrophobia (p=0.006). There was less concern for false positives if they had a prior benign biopsy (p=0.029) or prior CEM/MRI (p=0.005) and less concern for IV placement if they had dense breasts (p=0.007) or a previous callback (p=0.013). The screening population may accept CEM or MRI as a screening exam despite its risks and cost, especially patients with dense breasts and patients who have had prior CEM/MRI.

Development of a permeable phantom for dynamic contrast enhanced (DCE) imaging quality assurance: material characterization and testing

The wide-spread use of contrast-enhanced imaging is often combined with pharmaco-kinetic modeling to estimate the level of perfusion and/or permeability of the tissue or tumour under investigation. Despite the availability of advanced experimental methods and phantoms to test the accuracy of blood flow and transfer rates, the reliable estimation of tissue permeability following kinetic modeling against a known truth is still outstanding. This work reports on the first two phases of the development of a tissue mimicking permeable hepatic perfusion phantom being tested under DCE-CT: material selection and fabrication, as well as property testing. The required properties of these synthetic materials include a tailored porous structure, tumor mimicking pore size and tumor mimicking permeability. Three phantom materials were investigated for their capabilities to address these requirements, i.e. polydimethylsiloxane (PDMS), thermoplastic polyurethane (TPU) and agar gel. Porous structures were made using different techniques such as phase separation micro-molding (for PDMS) and a particular leaching process (for PDMS and TPU). Manual pores were made on agar gel and all were characterized under SEM, micro-CT scan and pycnometer. TPU was selected as the phantom material of choice moving forward due to its high homogeneity in pore size ranging from 200 to 400 μm, which mimics tumor vasculature the best. TPU also has the highest permeability of the three materials and its stable structure provides good repeatability.

Impaired diagnosis and successful management of a rare intra-axial central nervous system plasmacytoma in a patient with multiple myeloma

Intracranial central nervous system (CNS) plasmacytomas assoiated with multiple myeloma (MM) are exceptionally rare, and umors not involving either bone or dura are even rarer. This eport uniquely demonstrates a successful surgical approach in a 5-year old man with an intra-axial plasmacytoma as metastatic pread of MM. Initial diagnosis was uniquely challenging as magetic resonance (MR)-imaging findings were uncharacteristic for he lesion, and the patient had renal insufficiency which preluded the use of contrast-enhanced imaging. However, surgical anagement was clear due to clinical signs and imaging characeristics.

Are contrast media required for (68)Ga-DOTATOC PET/CT in patients with neuroendocrine tumours of the abdomen?

To determine the value of intravenous contrast medium in (68)Ga-DOTA-Phe(1)-Tyr(3)-octreotide - (68)Ga-DOTATOC - PET/CT for the detection of abdominal neuroendocrine tumours (NET). In fifty-five patients with known or suspected NETs of the abdomen PET/CT was performed on a 64-row multi-detector hybrid system. For PET, 150 MBq of (68)Ga-DOTATOC were injected intravenously. Full-dose unenhanced, and arterial- and venous-phase contrast-enhanced CT images were obtained. Unenhanced and contrast-enhanced PET/CT images were evaluated separately for the presence of NETs on a per-region basis, by two separate teams with different experience levels. On unenhanced PET/CT, sensitivity and specificity ranged from 89.3% (junior team) to 92% (senior team), and 99.1% (junior team) to 99.2% (senior team), respectively. On contrast-enhanced PET/CT, sensitivity and specificity ranged from 92.3% (junior team) to 98.5% (senior team), and 99.4% (junior team) to 99.5% (senior team), respectively. These increases in sensitivity and specificity, due to the use of contrast-enhanced images, were statistically significant (P < 0.05). Intravenous contrast medium only moderately, aleit significantly, improves the sensitivity of (68)Ga-DOTATOC PET/CT for the detection of abdominal NETs, and hardly affects specificity. Thus, while contrast enhancement is justified to achieve maximum sensitivity, unenhanced images may be sufficient for routine PET/CT in NET patients. Contrast media moderately improve the sensitivity of (68)Ga-DOTATOC PET/CT for neuroendocrine tumours. Contrast media hardly affect the specificity of (68)Ga-DOTATOC PET/CT for neuroendocrine tumours. Unenhanced PET/CT is sufficient for routine imaging of patients with neuroendocrine tumours.

Prevention of Contrast-Induced Nephropathy in the Emergency Department

Contrast-induced nephropathy is the third leading cause of hospital-acquired acute renal failure. Expanded use of contrast-enhanced imaging exposes an ever-widening number of patients to this renal toxin. We perform an evidence-based emergency medicine review comparing different therapies to prevent contrast-induced nephropathy. We limit our review to prophylactic therapies that are practical for an emergency department setting. We searched MEDLINE, EMBASE, and the Cochrane Library for randomized trials comparing a wide range of medications to prevent contrast-induced nephropathy. We defined contrast-induced nephropathy by a commonly used surrogate measure of renal failure: a 25% or 0.5 mg/dL absolute increase in serum creatinine level from baseline 48 to 72 hours postcontrast. We limited our review to only trials for patients with baseline renal insufficiency, who are most at risk for contrast-induced nephropathy. We excluded prophylactic protocols requiring more than 2 hours precontrast to initiate and any trials of experimental medications or those that required invasive monitoring. We used standard criteria to appraise the quality of published trials. We found 7 randomized trials; 3 using N-acetylcysteine, 2 using theophylline, and 1 each using bicarbonate and ascorbic acid. Although many of these trials showed statistically significant reductions in the risk for contrast-induced nephropathy, none were sufficiently powered to detect reductions in mortality rate or the need for dialytic therapy. Evidence from randomized trials shows that these interventions (theophylline, bicarbonate, and ascorbic acid) under review were appropriate to an ED setting and decreased the risk of contrast-induced nephropathy. The case for the effectiveness (N-acetylcysteine) was less certain.

Acetylcysteine protects against acute renal damage in patients with abnormal renal function undergoing a coronary procedure

ObjectivesWe sought to evaluate the efficacy of the antioxidant acetylcysteine in limiting the nephrotoxicity after coronary procedures. BackgroundThe increasingly frequent use of contrast-enhanced imaging for diagnosis or intervention in patients with coronary artery disease has generated concern about the avoidance of contrast-induced nephrotoxicity (CIN). Reactive oxygen species have been shown to cause CIN. MethodsWe prospectively studied 121 patients with chronic renal insufficiency (mean [±SD] serum creatinine concentration 2.8 ± 0.8 mg/dl) who underwent a coronary procedure. Patients were randomly assigned to receive either acetylcysteine (400 mg orally twice daily) and 0.45% saline intravenously, before and after injection of the contrast agent, or placebo and 0.45% saline. Serum creatinine and blood urea nitrogen were measured before, 48 h and 7 days after the coronary procedure. ResultsSeventeen (14%) of the 121 patients had an increase in their serum creatinine concentration of at least 0.5 mg/dl at 48 h after administration of the contrast agent: 2 (3.3%) of the 60 patients in the acetylcysteine group and 15 (24.6%) of the 61 patients in the control group (p < 0.001). In the acetylcysteine group, the mean serum creatinine concentration decreased significantly from 2.8 ± 0.8 to 2.5 ± 1.0 mg/dl (p < 0.01) at 48 h after injection of the contrast medium, whereas in the control group, the mean serum creatinine concentration increased significantly from 2.8 ± 0.8 to 3.1 ± 1.0 mg/dl (p < 0.01). ConclusionsProphylactic oral administration of the antioxidant acetylcysteine, along with hydration, reduces the acute renal damage induced by a contrast agent in patients with chronic renal insufficiency undergoing a coronary procedure.

Contrast-induced nephrotoxicity: the effects of vasodilator therapy.

The increasingly frequent use of contrast-enhanced imaging for diagnosis or intervention in patients with peripheral vascular disease has generated concern about the incidence and avoidance of contrast-induced nephrotoxicity (CIN). In this prospective study, we sought to identify those patients at greater risk of developing CIN and to evaluate the efficacy of vasodilator therapy with dopamine in limiting this complication. Baseline serum creatinine (Cr) concentrations were obtained on admission and daily for up to 72 hr after angiography in 222 patients undergoing 232 angiographic procedures. The preangiographic treatment was varied at 2-month intervals for 1 year. All patients received an intravenous infusion of 5% dextrose and 0.45% normal saline at a rate of 75 to 125 ml/hr. During the first interval patients received 12.5 g of 25% mannitol immediately prior to their contrast load, in addition to intravenous fluids. During the next 2-month period the patients were given renal dose dopamine intravenously (3 micrograms/kg/min) commencing the evening before angiography and continued to the next morning. During the latter half of the study the treatment regimens were modified so that the use of mannitol was restricted to patients with diabetes mellitus and dopamine to patients with serum creatinine concentrations of > or = 2 mg/dl. Postangiographic elevation in Cr occurred in 2, 10.4, and 62% of studies in patients with baseline creatinine levels of < or = 1.2 mg/dl, 1.3 to 1.9 mg/dl, and > or = 2.0 mg/dl, respectively. None of the patients receiving dopamine experienced an elevation in creatinine. There was no statistical correlation between age, diabetes, or medication with calcium channel blockers and CIN.(ABSTRACT TRUNCATED AT 250 WORDS)