Investigative Radiology最新文献

Objectives: This study aimed to investigate the association between the use of linear and macrocyclic gadolinium-based contrast agents (GBCAs) and the subsequent development of Parkinson disease (PD).

Methods: In this retrospective cohort study, data were extracted from the Korean National Health Insurance Service database, comprising 1,038,439 individuals. From this population, 175,125 adults aged 40 to 60 years with no history of brain disease were identified. All patients including 3835 who were administered GBCA at least once were monitored until 2022 for the onset of PD. Propensity score (PS) matching was employed to compare the incidence of PD between those exposed to GBCAs (either linear or macrocyclic) and those not exposed (no-GBCA group).

Results: The final cohort consisted of 1175 subjects exposed to linear GBCAs, 2334 exposed to macrocyclic GBCAs, and 171,616 unexposed to any GBCA (no-GBCA group). After PS matching, PD incidence was significantly higher in the linear GBCA group compared with the no-GBCA group (0.9% vs 0.0%, P = 0.002) and was also significantly higher in the macrocyclic GBCA group than in the no-GBCA group (0.5% vs 0.04%, P = 0.003). No significant difference in PD incidence was observed between the linear and macrocyclic GBCA groups.

Conclusions: Exposure to GBCAs was linked to an increased risk of developing PD in this large population-based study. The risk of PD did not differ significantly between linear and macrocyclic GBCAs.

Objectives: Double-dose contrast-enhanced brain imaging improves tumor delineation and detection of occult metastases but is limited by concerns about gadolinium-based contrast agents' effects on patients and the environment. The purpose of this study was to test the benefit of a deep learning-based contrast signal amplification in true single-dose T1-weighted (T-SD) images creating artificial double-dose (A-DD) images for metastasis detection in brain magnetic resonance imaging.

Materials and methods: In this prospective, multicenter study, a deep learning-based method originally trained on noncontrast, low-dose, and T-SD brain images was applied to T-SD images of 30 participants (mean age ± SD, 58.5 ± 11.8 years; 23 women) acquired externally between November 2022 and June 2023. Four readers with different levels of experience independently reviewed T-SD and A-DD images for metastases with 4 weeks between readings. A reference reader reviewed additionally acquired true double-dose images to determine any metastases present. Performances were compared using Mid-p McNemar tests for sensitivity and Wilcoxon signed rank tests for false-positive findings.

Results: All readers found more metastases using A-DD images. The 2 experienced neuroradiologists achieved the same level of sensitivity using T-SD images (62 of 91 metastases, 68.1%). While the increase in sensitivity using A-DD images was only descriptive for 1 of them (A-DD: 65 of 91 metastases, +3.3%, P = 0.424), the second neuroradiologist benefited significantly with a sensitivity increase of 12.1% (73 of 91 metastases, P = 0.008). The 2 less experienced readers (1 resident and 1 fellow) both found significantly more metastases on A-DD images (resident, T-SD: 61.5%, A-DD: 68.1%, P = 0.039; fellow, T-SD: 58.2%, A-DD: 70.3%, P = 0.008). They were therefore able to use A-DD images to increase their sensitivity to the neuroradiologists' initial level on regular T-SD images. False-positive findings did not differ significantly between sequences. However, readers showed descriptively more false-positive findings on A-DD images. The benefit in sensitivity particularly applied to metastases ≤5 mm (5.7%-17.3% increase in sensitivity).

Conclusions: A-DD images can improve the detectability of brain metastases without a significant loss of precision and could therefore represent a potentially valuable addition to regular single-dose brain imaging.

Purpose: The aim of this study was to determine in a prospective patient study the accuracy of areal bone mineral density (aBMD) measurements with spectral localizer radiographs obtained with a clinical photon-counting detector computed tomography (PCD-CT) scanner in comparison with dual-energy x-ray absorptiometry (DXA).

Methods: In this institutional review board-approved, prospective study, 41 patients (15 females, 26 males; mean age 61.3 years, age range 35-78 years) underwent PCD-CT of the abdomen with a spectral localizer radiograph (tube voltage 140 kVp, tube current 30 mA) and DXA within a median of 45 days. aBMD values were derived for lumbar vertebrae L1-L4 from both methods and were compared with linear regression, Pearson correlation, intraclass correlation coefficients (ICCs), and Bland-Altman plots. T-scores were calculated on a patient level and were compared between methods.

Results: DXA and spectral localizer radiographs showed strong correlation in aBMD measurements ( R = 0.97, P < 0.001) and patient level T-scores ( R = 0.99, P < 0.001). There was a strong agreement between aBMD from both methods (ICC, 0.96; 95% CI, 0.94-0.97). Bland-Altman analysis revealed a very small mean difference in aBMD between methods (mean absolute error 0.019 g/cm 2 ) with narrow limits of agreement (-0.083 g/cm 2 to 0.121 g/cm 2 ). Similarly, there were small differences in regard to the T-score (mean absolute error 0.156) with narrow limits of agreement (-0.422 to 0.734) between methods. ICCs indicated an excellent agreement between T-scores from DXA and spectral localizer radiographs (ICC, 0.98; 95% confidence interval, 0.95-0.99).

Conclusions: Our prospective patient study indicates that spectral localizer radiographs obtained with a clinical PCD-CT system enable accurate quantification of the lumbar bone areal mineral density. This opens up the opportunity for opportunistic screening of osteoporosis in patients who undergo CT for other indications.

Objectives: Anti-amyloid-beta immunotherapy requires frequent MRI screening for amyloid-related imaging abnormalities-hemorrhage subtype (ARIA-H), consisting of cerebral microbleeds (CMB) and/or superficial siderosis (SS), using gradient-recalled echo (GRE) or susceptibility-weighted imaging (SWI). Screening MRI sequences for ARIA-H may benefit from acceleration to maximize patient enrollment by increased throughput and reduced motion degradation. This study assessed the diagnostic performance of standard GRE and SWI to echo-planar imaging (EPI) accelerated substitutions for detecting CMB and SS.

Materials and methods: This retrospective single-center rater study included 50 patients, 25 with CMB and 25 patients without CMB (median age 77 y, IQR: 70 to 82 y; 30 of 50 female) who were imaged with FDG PET-3T MRI from April to July 2023. Standard GRE (90 s) and SWI (192 s) were compared with an EPI-accelerated GRE (aGRE; 13 s, 86% time reduction) and an EPI-accelerated SWI substitution (aSWI; 33 s, 83% time reduction). Three board-certified neuroradiologists independently reported CMB and SS (per ARIA-H monitoring guidelines), perceived image quality and motion for each sequence. There were 240 total assessments per rater (the 4 different sequences for the 50 patients plus 10 duplicated patients). Sensitivity, specificity, positive and negative predictive values, area under the curve (AUC), inter-rater and intrarater agreement were determined for each sequence and rater.

Results: The aggregate AUCs for the 4 individual sequences were excellent for detecting CMB (0.84 to 0.94) and SS (0.89 to 1.00) without statistical differences observed between standard and EPI-accelerated substitutions. Both aGRE and aSWI had high negative predictive values (96.5% to 100%). There were modest quantitative correlations between standard and accelerated sequences (0.606 and 0.391 for GRE and SWI, respectively), no differences in CMB count for aGRE (bias 0.01, P=0.895), but reduced CMB count with aSWI (bias -1.12, P=0.014). Inter-rater agreements were mildly reduced for both GRE versus aGRE (eg, 0.757 to 0.622 for CMB detection) and SWI versus aSWI (eg, 0.834 to 0.649 for SS detection). Perceived image quality for accelerated sequences was reduced, but with less motion observed with aSWI.

Conclusions: The aGRE and aSWI sequences shorten scan times 86% and 83%, respectively, with similar diagnostic performance for ARIA-H screening, but reduced rater agreement and perceived image quality.

Objectives: This study aimed to compare biventricular cine measurements and quantitative maps of myocardial T1 and T2 relaxation times at field strengths ranging from 0.55T to 1.5T in patients with a clinical indication for cardiac magnetic resonance imaging (CMR). Establishing the feasibility of low-field CMR may improve accessibility due to easier siting and lower cost of the low-field systems.

Materials and methods: Thirteen patients underwent same-day comparative CMR at 0.55T and on a commercial scanner at 1.5T. We examined all individuals with breath-held segmented bSSFP cine sequences for volumetric assessment of the left ventricle (LV), right ventricle (RV), and visual assessment of wall motion abnormalities (WMA) and valve pathologies. The quantitative T1 and T2 maps were acquired in 3 short-axis views for tissue characterization. Blinded readers scored the image quality on a 3-point Likert scale. Ten healthy volunteers were additionally examined at 0.55T to obtain reference values for the parametric maps.

Results: Functional analysis of both ventricles at low-field CMR has a reasonable correlation (r=0.94 to 0.99) with conventional 1.5T measurements. LV ejection fraction (EF) (P=0.62) and RV measurements (all P>0.05) were highly reproducible, but LV absolute volumetric measurements were slightly lower at the low-field strength (all P<0.05). T1 and T2 relaxation times correlated strongly between field strengths (r=0.79; P<0.01 and r=0.63; P=0.02). Reference values from the volunteers were 678.6±13.5 ms (T1) and 66.5±4.1 ms (T2). Overall, good image quality was achieved, and visual assessment showed excellent agreement with 1.5T. Trigger artifacts occurred more frequently during 0.55T scans compared with 1.5T. Correct clinical stratification of volumetric parameters, WMA, valve pathologies, and parametric maps was possible in 94% of all cases.

Conclusions: CMR at 0.55T provides a comprehensive assessment of function, structure, and tissue characterization comparable to that of 1.5T. The diagnostic accuracy in this clinical cohort is high. Identification of the specific trigger problems and optimization of the trigger technique could help to overcome the slight inaccuracies in the LV absolute volumetric measurements. Low-field CMR holds promise for expanding access to this valuable diagnostic tool, benefiting patients worldwide and on an individual level.

Objectives: Quantitative chemical exchange saturation transfer (CEST) breast imaging is limited by pronounced fat-induced artifacts. The strongest fat artifact, appearing between [-2, -4] ppm in the Z-spectrum, directly overlaps the signal of the exchange-relayed nuclear Overhauser effect (rNOE) at around -3.5 ppm, a key biomarker for protein content and cellularity, making accurate rNOE-CEST evaluation extremely challenging. The aim of this study is to evaluate rNOE-CEST contrast corrected for fat-related artifacts using a novel, fully software-based fat correction method in breast cancer patients.

Materials and methods: FATLESS (Fat Attenuation Technique using Lipid signal Estimation and Simulated Saturations in postprocessing) was developed for correcting fat-related artifacts across the entire Z-spectrum in CEST MRI. The FATLESS method estimates fat signals from residual signals at the direct water saturation offset (0 ppm) while accounting for partial saturation of fat resonances. FATLESS was retrospectively applied to 7T CEST data from breast cancer patients (acquired September 2018 to May 2019). Resulting fat-corrected rNOE, amide, and guanidino MTRRex contrast values were quantified from 2D snapshot GRE CEST with low saturation power (B1=0.6, 0.9 μT). Kruskal-Wallis tests and Pearson correlation analyses were used to compare MTRRex values between tumor and normal-appearing fibroglandular tissue and assess correlations with Ki-67, a tumor proliferation marker.

Results: Nine biopsy-confirmed breast cancer patients [mean age, 50 y ± 10 (SD)] and 7 healthy controls [mean age, 25 y ± 4 (SD)] were included. Fat-corrected MTRRex rNOE maps were validated in phantom and in vivo data, confirming independence from fat artifacts using the FATLESS method. Tumor regions showed significantly higher fat-corrected MTRRex rNOE values than healthy tissue (+140% mean increase, P<0.001). A strong positive correlation was found between fat-corrected MTRRex rNOE values and Ki-67 (R² = 0.71).

Conclusions: The developed FATLESS fat correction method enables full utilization of all CEST MRI contrasts in the human breast. The observed significant rNOE contrast elevation and strong correlation with tumor proliferation highlight its potential as a non-invasive imaging biomarker for breast cancer characterization.

Rationale and objectives: Dual-source photon-counting CT (DS-PCCT) facilitates an unprecedented combination of spectral information and ultra-high resolution in whole-body imaging of multiple myeloma. This study explored the distinct characteristics of soft tissue, fat, and calcium in virtual monoenergetic images (VMI) with low photon energy, aiming to identify criteria of lesion vitality.

Materials and methods: This retrospective study included 51 patients with multiple myeloma (67.1±10.1 y, 36 men) who underwent unenhanced whole-body DS-PCCT between October 2024 and February 2025. Three board-certified radiologists measured CT numbers within 169 osteolytic lesions (85 active) and their surrounding tissues. Differences between 40 and 70 keV were compared among active and inactive lesions. In addition, the presence of intralesional fat, calcifications, hypodense rims, homogeneity, and highlighting in color-coded virtual non-calcium maps was assessed subjectively.

Results: The attenuation difference between 40 and 70 keV VMI was markedly larger in active than inactive lesions [median 19.3 (interquartile range: 12.7-27.0) vs. -3.8 (-26.1 to 17.0) HU; P <0.001]. Homogenous density (86.3% vs. 2.4%) and conspicuous color-coding (94.9 vs. 68.7%) were more common in active myeloma, whereas intralesional fat (10.6 vs. 72.2%), calcifications (1.6% vs. 40.1%), and hypodense rims (0 vs. 37.3%) were more frequent in inactive lesions (all P <0.001). Interrater measurement reliability was excellent (intraclass correlation coefficient ≥0.95), and agreement for all qualitative criteria was high (Krippendorff α ≥0.85).

Conclusions: This investigation on whole-body DS-PCCT demonstrated a significant difference in attenuation changes from 70 to 40 keV VMI across multiple myeloma patients with a therapy response versus initial diagnosis and disease progression. Qualitative characteristics of medullary lesions, such as heterogeneity, partial recalcification, or a hypodense rim ("halo sign"), can serve as additional indicators of therapy response.