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Objectives To compare the diagnostic performance of contrast-enhanced spectral mammography (CESM) to digital mammography (MG) and magnetic resonance imaging (MRI) in a prospective two-centre, multi-reader study. Methods One hundred seventy-eight women (mean age 53 years) with invasive breast cancer and/or DCIS were included after ethics board approval. MG, CESM and CESM + MG were evaluated by three blinded radiologists based on amended ACR BI-RADS criteria. MRI was assessed by another group of three readers. Receiver-operating characteristic (ROC) curves were compared. Size measurements for the 70 lesions detected by all readers in each modality were correlated with pathology. Results Reading results for 604 lesions were available (273 malignant, 4 high-risk, 327 benign). The area under the ROC curve was significantly larger for CESM alone (0.84) and CESM + MG (0.83) compared to MG (0.76) (largest advantage in dense breasts) while it was not significantly different from MRI (0.85). Pearson correlation coefficients for size comparison were 0.61 for MG, 0.69 for CESM, 0.70 for CESM + MG and 0.79 for MRI. Conclusions This study showed that CESM, alone and in combination with MG, is as accurate as MRI but is superior to MG for lesion detection. Patients with dense breasts benefitted most from CESM with the smallest additional dose compared to MG. Key Points • CESM has comparable diagnostic performance (ROC-AUC) to MRI for breast cancer diagnostics . • CESM in combination with MG does not improve diagnostic performance . • CESM has lower sensitivity but higher specificity than MRI . • Sensitivity differences are more pronounced in dense and not significant in non-dense breasts . • CESM and MRI are significantly superior to MG, particularly in dense breasts .

In this study, we compared the performance of gadobutrol and meglumine gadoterate, two macrocyclic non-ionic and ionic contrast agents, for evaluating quantitative perfusion parameters of pituitary macroadenomas using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Patients with pituitary macroadenomas were prospectively enrolled and randomly assigned to be administered gadobutrol or meglumine gadoterate for MRI. Perfusion parameters of the pituitary macroadenoma, including Ktrans, Kep, Ve, and Vp, were measured using DCE-MRI. In total, 60 patients (mean age: 59.7 ± 13.7 years; 40 men) were evaluated. The non-inferiority test confirmed that gadobutrol was comparable to meglumine gadoterate for measuring the Ktrans of the pituitary macroadenoma. Kep was significantly higher with gadobutrol ( P  = 0.001) irrespective of tumor functional status and aggressiveness. Ktrans, Ve, and Vp and pre- and post-contrast T1-signal intensities of the tumor did not differ significantly for contrast agents. Perfusion parameters were not significantly associated with diagnostic performance in distinguishing the tumor functional status ( P  > 0.05). In summary, gadobutrol is non-inferior to meglumine gadoterate for the Ktrans measurement of pituitary macroadenomas. However, gadobutrol may lead to higher Kep, regardless of tumor functional status and aggressiveness. Awareness of this variation is crucial to preventing misinterpretation of vascular dynamics in pituitary macroadenomas.

Objectives To investigate the feasibility of low-radiation dose and low iodinated contrast medium (ICM) dose protocol combining low-tube voltage and deep-learning reconstruction (DLR) algorithm in thin-slice abdominal CT. Methods This prospective study included 148 patients who underwent contrast-enhanced abdominal CT with either 120-kVp (600 mgL/kg, n  = 74) or 80-kVp protocol (360 mgL/kg, n  = 74). The 120-kVp images were reconstructed using hybrid iterative reconstruction (HIR) (120-kVp-HIR), while 80-kVp images were reconstructed using HIR (80-kVp-HIR) and DLR (80-kVp-DLR) with 0.5 mm thickness. Size-specific dose estimate (SSDE) and iodine dose were compared between protocols. Image noise, CT attenuation, and contrast-to-noise ratio (CNR) were quantified. Noise power spectrum (NPS) and edge rise slope (ERS) were used to evaluate noise texture and edge sharpness, respectively. The subjective image quality was rated on a 4-point scale. Results SSDE and iodine doses of 80-kVp were 40.4% (8.1 ± 0.9 vs. 13.6 ± 2.7 mGy) and 36.3% (21.2 ± 3.9 vs. 33.3 ± 4.3 gL) lower, respectively, than those of 120-kVp (both, p  < 0.001). CT attenuation of vessels and solid organs was higher in 80-kVp than in 120-kVp images (all, p  < 0.001). Image noise of 80-kVp-HIR and 80-kVp-DLR was higher and lower, respectively than that of 120-kVp-HIR (both p  < 0.001). The highest CNR and subjective scores were attained in 80-kVp-DLR (all, p  < 0.001). There were no significant differences in average NPS frequency and ERS between 120-kVp-HIR and 80-kVp-DLR ( p  ≥ 0.38). Conclusion Compared with the 120-kVp-HIR protocol, the combined use of 80-kVp and DLR techniques yielded superior subjective and objective image quality with reduced radiation and ICM doses at thin-section abdominal CT. Clinical relevance statement Scanning at low-tube voltage (80-kVp) combined with the deep-learning reconstruction algorithm may enhance diagnostic efficiency and patient safety by improving image quality and reducing radiation and contrast doses of thin-slice abdominal CT. Key Points Reducing radiation and iodine doses is desirable; however, contrast and noise degradation can be detrimental. The 80-kVp scan with the deep-learning reconstruction technique provided better images with lower radiation and contrast doses. This technique may be efficient for improving diagnostic confidence and patient safety in thin-slice abdominal CT.

This study reports the use of gadolinium-based AGuIX nanoparticles (NPs) as a theranostic tool for both image-guided radiation therapy and radiosensitization of brain tumors. Pharmacokinetics and regulatory toxicology investigations were performed on rodents. The AGuIX NPs' tumor accumulation was studied by MRI before 6-MV irradiation. AGuIX NPs exhibited a great safety profile. A single intravenous administration enabled the tumor delineation by MRI with a T tumor contrast enhancement up to 24 h, and the tumor volume reduction when combined with a clinical 6-MV radiotherapy. This study demonstrates the efficacy and the potential of AGuIX NPs for image-guided radiation therapy, promising properties that will be assessed in the upcoming Phase I clinical trial.

BackgroundAcute kidney injury (AKI) after transcatheter aortic valve implantation (TAVI) is a serious complication which is associated with increased mortality. The RenalGuard system was developed to reduce the risk of AKI after contrast media exposition by furosemide-induced diuresis with matched isotonic intravenous hydration. The aim of this study was to examine the effect of the RenalGuard system on the occurrence of AKI after TAVI in patients with chronic kidney disease.MethodsThe present study is a single-center randomized trial including patients with severe aortic valve stenosis undergoing TAVI. Overall, a total of 100 patients treated by TAVI between January 2017 and August 2018 were randomly assigned to a periprocedural treatment with the RenalGuard system or standard treatment by pre- and postprocedural intravenous hydration. Primary endpoint was the occurrence of AKI after TAVI, and secondary endpoints were assessed according to valve academic research consortium 2 criteria.ResultsOverall, the prevalence of AKI was 18.4% (n = 18). The majority of these patients developed mild AKI according to stage 1. Comparing RenalGuard to standard therapy, no significant differences were observed in the occurrence of AKI (RenalGuard: 21.3%; control group: 15.7%; p = 0.651). In addition, there were no differences between the groups with regard to 30-day and 12-month mortality and procedure-associated complication rates.ConclusionIn this randomized trial, we did not detect a reduction in AKI after TAVI by using the RenalGuard system. A substantial number of patients with chronic kidney disease developed AKI after TAVI, whereas the majority presented with mild AKI according to stage 1 (ClinicalTrials.gov number NCT04537325).

ObjectiveTo compare the effect of contrast medium iodine concentration on contrast enhancement, heart rate, and injection pressure when injected at a constant iodine delivery rate in coronary CT angiography (CTA).MethodsOne thousand twenty-four patients scheduled for coronary CTA were prospectively randomized to receive one of four contrast media: iopromide 300 mg I/ml, iohexol 350 mg I/ml, iopromide 370 mg I/ml, or iomeprol 400 mg I/ml. Contrast media were delivered at an equivalent iodine delivery rate of 2.0 g I/s. Intracoronary attenuation was measured and compared (per vessel and per segment). Heart rate before and after contrast media injection was documented. Injection pressure was recorded (n = 403) during contrast medium injection and compared between groups.ResultsIntracoronary attenuation values were similar for the different contrast groups. The mean attenuation over all segments ranged between 384 HU for 350 mg I/ml and 395 HU for 400 mg I/ml (p = 0.079). Dose-length product (p = 0.8424), signal-to-noise ratio (all p > 0.05), time to peak (p = 0.324), and changes in heart rate (p = 0.974) were comparable between groups. The peak pressures differed: 197.4 psi for 300 mg I/ml (viscosity 4.6 mPa s), 229.8 psi for 350 mg I/ml (10.4 mPa s), 216.1 psi for 370 mg I/ml (9.5 mPa s), and 243.7 psi for 400 mg I/ml (12.6 mPa s) (p < 0.0001).ConclusionIntravascular attenuation and changes in heart rate are independent of iodine concentration when contrast media are injected at the same iodine delivery rate. Differences in injection pressures are associated with the viscosity of the contrast media.Key Points• The contrast enhancement in coronary CT angiography is independent of the iodine concentration when contrast media are injected at body temperature (37 °C) with the same iodine delivery rate.• Iodine concentration does not influence the change in heart rate when contrast media are injected at identical iodine delivery rates.• For a fixed iodine delivery rate and contrast temperature, the viscosity of the contrast medium affects the injection pressure.

Clearance of an intravenous iohexol dose of 3235 mg is used to assess glomerular filtration rate (GFR), although systematic assessment of its pharmacokinetic (PK) properties is incomplete. The objectives of the present investigations were (i) to assess potential interactions of iohexol with important drug transporters, and (ii) whether a 259 mg dose could replace the current standard dose. In vitro, we evaluated whether iohexol inhibits or is transported by renal transporters (hOAT1/3, hOCT2, and hMATE1/2K) or other transporters (hOATP1B1/3, hOCT1, and hMDR1) using cell‐based and vesicle‐based systems. In vivo, we conducted a clinical trial with 12 volunteers with the administration of single intravenous doses of 3235 mg (“reference”) and 259 mg (“test”) using a changeover design. Plasma and urine samples were collected up to 24 h postdose. We assessed the dose linearity of iohexol pharmacokinetics using the standard bioequivalence approach and conducted a population PK analysis to characterize its profile. Our in vitro findings indicate that iohexol is neither a substrate nor a significant inhibitor of the transporters, suggesting it is unlikely to participate in transporter‐mediated drug–drug interactions in vivo. In the clinical trial, the test/reference ratio for plasma clearance, calculated as dose divided by the area under the plasma concentration–time curve, was 1.01 (90% confidence interval 0.968–1.05), confirming dose linearity. Population PK analysis further supported these results, showing no significant effect of dose on renal clearance and negligible nonrenal clearance of iohexol. Low‐dose iohexol is a suitable marker for precise GFR measurement, even when coadministered with other drugs.

Background For two decades, bright-blood late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) has been considered the reference standard for the non-invasive assessment of myocardial viability. While bright-blood LGE can clearly distinguish areas of myocardial infarction from viable myocardium, it often suffers from poor scar-to-blood contrast, making subendocardial scar difficult to detect. Recently, we proposed a novel dark-blood LGE approach that increases scar-to-blood contrast and thereby improves subendocardial scar conspicuity. In the present study we sought to assess the clinical value of this novel approach in a large patient cohort with various non-congenital ischemic and non-ischemic cardiomyopathies on both 1.5 T and 3 T CMR scanners of different vendors. Methods Three hundred consecutive patients referred for clinical CMR were randomly assigned to a 1.5 T or 3 T scanner. An entire short-axis stack and multiple long-axis views were acquired using conventional phase sensitive inversion recovery (PSIR) LGE with TI set to null myocardium (bright-blood) and proposed PSIR LGE with TI set to null blood (dark-blood), in a randomized order. The bright-blood LGE and dark-blood LGE images were separated, anonymized, and interpreted in a random order at different time points by one of five independent observers. Each case was analyzed for the type of scar, per-segment transmurality, papillary muscle enhancement, overall image quality, observer confidence, and presence of right ventricular scar and intraventricular thrombus. Results Dark-blood LGE detected significantly more cases with ischemic scar compared to conventional bright-blood LGE (97 vs 89, p  = 0.008), on both 1.5 T and 3 T, and led to a significantly increased total scar burden (3.3 ± 2.4 vs 3.0 ± 2.3 standard AHA segments, p  = 0.015). Overall image quality significantly improved using dark-blood LGE compared to bright-blood LGE (81.3% vs 74.0% of all segments were of highest diagnostic quality, p  = 0.006). Furthermore, dark-blood LGE led to significantly higher observer confidence (confident in 84.2% vs 78.4%, p  = 0.033). Conclusions The improved detection of ischemic scar makes the proposed dark-blood LGE method a valuable diagnostic tool in the non-invasive assessment of myocardial scar. The applicability in routine clinical practice is further strengthened, as the present approach, in contrast to other recently proposed dark- and black-blood LGE techniques, is readily available without the need for scanner adjustments, extensive optimizations, or additional training.

This study aims to explore the feasibility of applying the “Three-Low” technique (low injection rate, low iodine contrast volume, low radiation dose) in coronary CT angiography (CCTA). We prospectively collected data from 90 patients who underwent CCTA at our hospital between 2021 and 2024. The patients were randomly assigned to either the experimental group ( n  = 45) or the control group ( n  = 45). The experimental group parameters were as follows: injection rate of 3.5-4.0 ml/s, iodine contrast volume of 35–40 ml, tube voltage of 100 kVp, and tube current of 250 mA. The control group parameters were: injection rate of 4.5-5.0 ml/s, iodine contrast volume of 45–50 ml, tube voltage of 120 kVp, and tube current of 450 mA. Both groups received a high-concentration, non-ionic, water-soluble contrast agent (Iomeprol, 40 gl/100 ml). The heart rate of all patients was ≤ 70 bpm, and breath-hold scanning was performed after breathing training. The study compared the CT values of the left anterior descending artery, left circumflex artery, right coronary artery, and aorta, as well as background noise, signal-to-noise ratio (SNR), volumetric CT dose index, dose-length product, effective radiation dose, and total iodine dose between the two groups. In the control group, no cases of contrast extravasation occurred, while 6 cases of extravasation were observed in the experimental group ( p  = 0.026). There was no significant difference between the groups in terms of vascular image quality (mean vascular image quality score: experimental group 4.27 ± 0.62 vs. control group 4.24 ± 0.57, p  > 0.05) or vascular motion artifact score (mean vascular motion artifact score: experimental group 4.20 ± 0.59 vs. control group 4.13 ± 0.55, p  > 0.05). However, significant differences were found between the experimental and control groups in the CT values of the left anterior descending artery (experimental group: 571.31 ± 49.66 HU vs. control group: 449.20 ± 36.80 HU, p  < 0.05), left circumflex artery (experimental group: 570.41 ± 49.98 HU vs. control group: 450.95 ± 39.27 HU, p  < 0.05), right coronary artery (experimental group: 584.52 ± 53.70 HU vs. control group: 452.66 ± 40.67 HU, p  < 0.05), aorta (experimental group: 624.91 ± 48.99 HU vs. control group: 465.36 ± 34.37 HU, p  < 0.05), background noise (experimental group: 24.76 ± 1.97 vs. control group: 19.09 ± 1.69, p  < 0.05), SNR (experimental group: 25.30 ± 1.81 vs. control group: 24.47 ± 1.75, p  < 0.05), volumetric CT dose index (experimental group: 22.97 ± 1.47 mGy vs. control group: 50.53 ± 4.89 mGy, p  < 0.05), dose-length product (experimental group: 363.68 ± 21.45 mGy·cm vs. control group: 782.41 ± 58.20 mGy·cm, p  < 0.05), and effective radiation dose (experimental group: 5.09 ± 0.30 mSv vs. control group: 10.95 ± 0.81 mSv, p  < 0.05).The results of the Fisher test indicated that the extravasation rate was significantly higher in the high injection rate group compared to the low injection rate group ( P  = 0.024). The “Three-Low” technique in CCTA imaging effectively reduces the incidence of contrast extravasation caused by high injection rates and decreases the radiation dose, making it a highly feasible option for clinical application and worthy of broader adoption.

This study evaluates a novel dark-blood late gadolinium enhancement (LGE) cardiovascular magnetic resonance imaging (CMR) method, without using additional magnetization preparation, and compares it to conventional bright-blood LGE, for the detection of ischaemic myocardial scar. LGE is able to clearly depict myocardial infarction and macroscopic scarring from viable myocardium. However, due to the bright signal of adjacent left ventricular blood, the apparent volume of scar tissue can be significantly reduced, or even completely obscured. In addition, blood pool signal can mimic scar tissue and lead to false positive observations. Simply nulling the blood magnetization by choosing shorter inversion times, leads to a negative viable myocardium signal that appears equally as bright as scar due to the magnitude image reconstruction. However, by combining blood magnetization nulling with the extended grayscale range of phase-sensitive inversion-recovery (PSIR), a darker blood signal can be achieved whilst a dark myocardium and bright scar signal is preserved. LGE was performed in nine male patients (63 ± 11y) using a PSIR pulse sequence, with both conventional viable myocardium nulling and left ventricular blood nulling, in a randomized order. Regions of interest were drawn in the left ventricular blood, viable myocardium, and scar tissue, to assess contrast-to-noise ratios. Maximum scar transmurality, scar size, circumferential scar angle, and a confidence score for scar detection and maximum transmurality were also assessed. Bloch simulations were performed to simulate the magnetization levels of the left ventricular blood, viable myocardium, and scar tissue. Average scar-to-blood contrast was significantly (p < 0.001) increased by 99% when nulling left ventricular blood instead of viable myocardium, while scar-to-myocardium contrast was maintained. Nulling left ventricular blood also led to significantly (p = 0.038) higher expert confidence in scar detection and maximum transmurality. No significant changes were found in scar transmurality (p = 0.317), normalized scar size (p = 0.054), and circumferential scar angle (p = 0.117). Nulling left ventricular blood magnetization for PSIR LGE leads to improved scar-to-blood contrast and increased expert confidence in scar detection and scar transmurality. As no additional magnetization preparation is used, clinical application on current MR systems is readily available without the need for extensive optimizations, software modifications, and/or additional training.