Investigative Radiology

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Human Hair as a Possible Surrogate Marker of Retained Tissue Gadolinium: A Pilot Autopsy Study Correlating Gadolinium Concentrations in Hair With Brain and Other Tissues Among Decedents Who Received Gadolinium-Based Contrast Agents

imageObjectives
We used laser ablation inductively coupled plasma mass spectrometry to quantify gadolinium in hair samples from autopsy cases with gadolinium-based contrast agent (GBCA) exposure. Hair gadolinium data were correlated with gadolinium concentrations in brain, skin, and bone tissues from the same case to investigate a potential noninvasive method for gadolinium quantification and monitoring.
Materials and Methods
Medical records from autopsy cases at our institution were screened for history of GBCA exposure. Cases with exposure to a single type of GBCA with the most recent injection occurring within 1 year were identified and included in the study. The concentration of gadolinium in hair samples was analyzed by laser ablation inductively coupled plasma mass spectrometry, and brain (globus pallidus, dentate nucleus, white matter), bone, and skin tissues were analyzed by bulk inductively coupled plasma mass spectrometry. The mean of the maximum value in the hair samples was used to generate a representative measurement of the hair gadolinium concentration for each case. A linear regression analysis between each tissue type and hair was conducted to assess for possible correlation.
Results
Tissue and hair samples from 18 autopsies (16 cases with exposure to GBCA, 2 controls) were included in the study. Comparing the different tissues revealed good correlation between some tissue types. The best model fit occurred between white matter and hair (R2 = 0.83; P < 0.0001) followed by the comparison between dentate nucleus and hair (R2 = 0.72; P < 0.0001) and dentate nucleus and skin (R2 = 0.70; P < 0.0001).
Conclusions
A significant correlation in this study between hair gadolinium concentrations and brain and skin gadolinium concentrations suggests that hair may serve as a safe and effective biomonitoring tissue for patients who receive GBCA injections.

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https://journals.lww.com/investigativeradiology/Fulltext/2020/10000/Human_Hair_as_a_Possible_Surrogate_Marker_of.2.aspx

A Solution for Homogeneous Liver Enhancement in Computed Tomography: Results From the COMpLEx Trial

imageObjectives
The aim of the study was to reach homogeneous enhancement of the liver, irrespective of total body weight (TBW) or tube voltage. An easy-to-use rule of thumb, the 10-to-10 rule, which pairs a 10 kV reduction in tube voltage with a 10% decrease in contrast media (CM) dose, was evaluated.
Materials and Methods
A total of 256 patients scheduled for an abdominal CT in portal venous phase were randomly allocated to 1 of 4 groups. In group 1 (n = 64), a tube voltage of 120 kV and a TBW-adapted CM injection protocol was used: 0.521 g I/kg. In group 2 (n = 63), tube voltage was 90 kV and the TBW-adapted CM dosing factor remained 0.521 g I/kg. In group 3 (n = 63), tube voltage was reduced by 20 kV and CM dosing factor by 20% compared with group 1, in line with the 10-to-10 rule (100 kV; 0.417 g I/kg). In group 4 (n = 66), tube voltage was decreased by 30 kV paired with a 30% decrease in CM dosing factor compared with group 1, in line with the 10-to-10 rule (90 kV; 0.365 g I/kg). Objective image quality was evaluated by measuring attenuation in Hounsfield units (HU), signal-to-noise ratio, and contrast-to-noise ratio in the liver. Overall subjective image quality was assessed by 2 experienced readers by using a 5-point Likert scale. Two-sided P values below 0.05 were considered significant.
Results
Mean attenuation values in groups 1, 3, and 4 were comparable (118.2 ± 10.0, 117.6 ± 13.9, 117.3 ± 21.6 HU, respectively), whereas attenuation in group 2 (141.0 ± 18.2 HU) was significantly higher than all other groups (P < 0.01). No significant difference in attenuation was found between weight categories 80 kg or less and greater than 80 kg within the 4 groups (P ≥ 0.371). No significant differences in subjective image quality were found (P = 0.180).
Conclusions
The proposed 10-to-10 rule is an easily reproducible method resulting in similar enhancement in portal venous CT of the liver throughout the patient population, irrespective of TBW or tube voltage.

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https://journals.lww.com/investigativeradiology/Fulltext/2020/10000/A_Solution_for_Homogeneous_Liver_Enhancement_in.5.aspx

Evaluation of the Reproducibility of Bolus Transit Quantification With Contrast-Enhanced Ultrasound Across Multiple Scanners and Analysis Software Packages—A Quantitative Imaging Biomarker Alliance Study

imageObjectives
Contrast enhanced ultrasound (CEUS) is now broadly used clinically for liver lesion detection and characterization. Obstacles to the efforts to quantify perfusion with CEUS have been the lack of a standardized approach and undocumented reproducibility. The use of multiple scanners and different analysis software packages compounds the degree of variability. Our objectives were to standardize a CEUS-based approach for quantification of perfusion-related parameters of liver lesions and to evaluate the variability of bolus transit parameters (rise time [RT], mean transit time [MTT], peak intensity, and area under the curve) obtained from various clinical ultrasound scanners and analysis software.
Materials and Methods
Bolus transit as a way of evaluating perfusion has been investigated both in vivo and in vitro in the past but without establishing its reproducibility. We developed a tissue flow phantom that produces time-intensity curves very similar to those extracted from clinical cine loops of liver lesions. We evaluated the variability of the bolus transit parameters with 4 commercial scanners (Philips iU22, Philips EPIQ, GE LOGIQ E9, and Siemens Acuson Sequoia) and 3 different analysis software packages in multiple trials (15 per scanner).
Results
The variability (coefficient of variation) from repeated trials and while using a single scanner and software was less than 8% for RT, less than 12% for MTT, less than 49% for peak intensity, and less than 50% for area under the curve. Currently, it is not possible to directly compare amplitude values from different scanners and analysis software packages owing to the arbitrary linearization algorithm used among manufacturers; however, it is possible for time parameters (RT and MTT). The variability when using a different scanner with the same analysis software package was less than 9% for RT and less than 21% for MTT. The variability when using a different analysis software with the same scanner was less than 9% for RT and less than 15% for MTT. In all the evaluations we have performed, RT is the least variable parameter, while MTT is only slightly more variable.
Conclusions
The present study will lay the groundwork for multicenter patient evaluations with CEUS quantification of perfusion-related parameters with the bolus transit technique. When using the protocol and method developed here, it is possible to perform perfusion quantification on different scanners and analysis software and be able to compare the results. The current work is the first study that presents a comparison of bolus transit parameters derived from multiple systems and software packages.

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https://journals.lww.com/investigativeradiology/Fulltext/2020/10000/Evaluation_of_the_Reproducibility_of_Bolus_Transit.3.aspx