The recent study by Hodi et al. published in the Journal of Clinical Oncology has evaluated unconventional response patterns during PD-1 inhibitor therapy using immune-related response criteria ...(irRC) in comparison with RECIST1.1, which constitutes an important step to further understand immune-related response phenomena. This commentary discusses the key observations in the study in terms of their implications and pitfalls, and describes unmet needs that remain to be addressed. The article also emphasizes the important role of tumor response criteria as a “common language” to describe the results of cancer treatment, and discusses future directions for further advances of the field of immuno-oncology.
Objectives
To evaluate the differences between filtered back projection (FBP) and model-based iterative reconstruction (MBIR) algorithms on semi-automatic measurements in subsolid nodules (SSNs).
...Methods
Unenhanced CT scans of 73 SSNs obtained using the same protocol and reconstructed with both FBP and MBIR algorithms were evaluated by two radiologists. Diameter, mean attenuation, mass and volume of whole nodules and their solid components were measured. Intra- and interobserver variability and differences between FBP and MBIR were then evaluated using Bland–Altman method and Wilcoxon tests.
Results
Longest diameter, volume and mass of nodules and those of their solid components were significantly higher using MBIR (
p
< 0.05) with mean differences of 1.1% (limits of agreement, −6.4 to 8.5%), 3.2% (−20.9 to 27.3%) and 2.9% (−16.9 to 22.7%) and 3.2% (−20.5 to 27%), 6.3% (−51.9 to 64.6%), 6.6% (−50.1 to 63.3%), respectively. The limits of agreement between FBP and MBIR were within the range of intra- and interobserver variability for both algorithms with respect to the diameter, volume and mass of nodules and their solid components. There were no significant differences in intra- or interobserver variability between FBP and MBIR (
p
> 0.05).
Conclusion
Semi-automatic measurements of SSNs significantly differed between FBP and MBIR; however, the differences were within the range of measurement variability.
Key points
•
Intra- and interobserver reproducibility of measurements did not differ between FBP and MBIR.
•
Differences in SSNs’ semi-automatic measurement induced by reconstruction algorithms were not clinically significant.
•
Semi-automatic measurement may be conducted regardless of reconstruction algorithm.
•
SSNs’ semi-automated classification agreement (pure vs. part-solid) did not significantly differ between algorithms.
Background
A novel measurement technique has been designed to assess femoral rotation deformation. The purpose of this study was to evaluate smartphone‐aided measurement, including measurement ...software, intra‐observer differences and the occurrence frequency of the unacceptable outliers.
Methods
Five positions (intact bone, external and internal rotations of 20° and 40° of the distal blocks after dividing the femoral shafts using a saw) were used in each of the five artificial femora. Guide wires were separately inserted into the proximal and distal ends of the model femora with a navigation system and the intersection angles between the guide wires were measured with a smartphone. The values obtained by two measurement software packages (Smart Tools and Super Swiss Army Knife) were compared with that measured on the overlapped computed tomography images.
Results
There were no significant differences between the intersection angles measured by smartphone and that measured on the overlapped images (P = 0.24). The mean absolute difference between pairs of measurements of the two software packages for all guide wire angles was 2.33 ± 2.34°, without statistically significant difference (P = 0.33). There was a significant correlation (r = 0.99) between the first and second (1 week apart) measurements with the same measurement tool. The values of offset capability index of the Smart Tools and the Super Swiss Army Knife measurement tools were 1.62 and 1.13, respectively.
Conclusion
Smartphone‐aided measurement technique could reliably assess femoral rotation deformation with more accurate angle measurement for software with zero calibration function.
A patent measurement technique has been designed to assess femoral rotation deformation. The aim of this study was to investigate and assess its possibility and reliability.
To estimate the critical duration of temporal summation for achromatic Goldmann III stimuli under the conditions of standard automated perimetry (SAP) and quantify response variability for ...short-duration stimuli.
Contrast thresholds were gathered using the method of constant stimuli for seven circular (0.48° diameter) incremental stimuli of varying duration (sum-of-frames equivalent: 8.3-198.3 ms), at an eccentricity of 8.8° along the four principal meridians of the visual field in two healthy, psychophysically experienced observers. Stimuli were presented on a high-resolution cathode ray tube display with a background luminance of 10 cd/m(2). Psychometric functions were fitted using a probit model and nonparametric local-linear analysis. The critical duration was estimated using iterative two-phase regression analysis, the results also being compared with values produced using previously published methods of analysis.
The median critical duration estimated using iterative two-phase regression analysis was 27.7 ms (IQR 22.5-29.8). A slight steepening of the psychometric function slope (lower variability) was observed for longer stimulus durations, using both probit and local-linear analysis techniques, but this was not statistically significant.
Critical duration estimates in this study are substantially shorter than those previously reported for a Goldmann III stimulus, under the conditions of SAP. Further work is required to firmly establish the relationship between measurement variability and the degree of local temporal and spatial summation.
The measurement of ventilation rates is crucial in understanding buildings’ performances, but can be a rather complex task due to the time-dependency of wind and buoyancy forces, which are ...responsible for the pressure differences that induce air movement across the envelope. Thus, assessing air change rate through one-time measurements during brief periods of time may not be a reliable indicator. In this paper, the variability in the measurement of ventilation rates using the decay technique was evaluated. To that end, two compartments of a typical single-family detached dwelling were selected as a case study and 132 tests were performed, considering two different boundary conditions (door closed and door open). This work allowed the large variability of the results to be highlighted, as the coefficient of variation ranged from 20% to 64%. Wind speed had a key effect on the results, especially because during the measurements indoor–outdoor temperature differences were not so significant. The possibility of using occupant-generated carbon dioxide as tracer gas was also analyzed, but problems of cross-contamination were identified.
Purpose
To assess intra‐ and interobserver variability in the apparent diffusion coefficient (ADC) measurements of pleural abnormalities.
Materials and Methods
Diffusion‐weighted magnetic resonance ...imaging was performed in 34 patients to characterize pleural abnormalities, with a 1.5T unit at b values of 0/150/500/800 sec/mm2. In two sessions held 3 months apart, on perfusion‐free ADC maps, two independent readers measured the ADC of pleural abnormalities (two readings for each reader in each case) using different methods of region‐of‐interest (ROI) positioning. In three methods, freehand ROIs were drawn within tumor boundaries to encompass the entire lesion on one or more axial slices (whole tumor volume WTV, three slices observer‐defined TSOD, single‐slice SS), while in two methods one or more ROIs were placed on the more restricted areas (multiple small round ROI MSR, one small round ROI OSR). Measurement variability between readings by each reader (intraobserver repeatability) and between readers in first reading (interobserver repeatability) were assessed using intraclass correlation coefficient (ICC) and coefficient of variation (CoV). Analysis of variance (ANOVA) was performed to compare ADC values between the different methods. The measurement time of each case for all methods in first reading was recorded and compared between methods and readers.
Results
All methods demonstrated good (MSR, OSR) and excellent (WTV, TSOD, SS) intra‐ and interreader agreement, with best and worst repeatability in WTV (lower ICC, 0.977; higher CoV, 3.5%) and OSR (lower ICC, 0.625; higher CoV, 22.8%), respectively. The lower 95% confidence interval of ICC resulted in fair to moderate agreement for OSR (up to 0.379) and in excellent agreement for WTV, TSV, and SS (up to 0.918). ADC values of OSR and MSR were significantly lower compared to other methods (P < 0.001). The OSR and SS required less measurement time (10 and 21/22 sec, respectively) compared to the others (P < 0.0001), while the WTV required the longest measurement time (132/134 sec) (P < 0.0001).
Conclusion
ADC measurements of pleural abnormalities are repeatable. The SS method has excellent repeatability, similar to WTV, but requires significantly less measurement time. Thus, its use should be preferred in clinical practice.
Level of Evidence: 4
Technical Efficacy: Stage 2
J. MAGN. RESON. IMAGING 2017;46:769–782
The comparison between methods, evaluation of portal hypertension and many other questions are still open issues in liver elastography. New elastographic applications are under evaluation and close ...to being used in clinical practice. Strain imaging has been incorporated into many disciplines and EFSUMB guidelines are under preparation. More research is necessary for improved evidence for clinical applications in daily practice. The Special Issue published papers on recent advances in development and application of Ultrasound Elastography.
Distress intolerance (DI), the inability to tolerate stressful experiences, has been linked to multiple psychiatric conditions and maladaptive coping patterns. Although DI is often considered a ...trait-like variable, evidence indicates that self-report and behavioral indices of DI can be manipulated by contextual factors. Understanding such contextual influences is important given evidence of unexpected variability in these presumed trait-like measures over brief intervals. The current study examined the influence of context (manipulated by priming concepts of “Interminability” and “Brevity”) in predicting behavioral persistence, in relation to self-reported DI. Results indicated that priming Brevity was associated with terminating a cold-pressor task more quickly. Self-reported DI was linked to earlier termination, but there was no interaction between self-reported DI and priming condition. Results indicate that contextual cues modulate performance on behavioral measures of DI. Hence, models of DI should consider both trait-like and contextual factors in understanding variability in DI measures.
To address the need for more objective and quantitative measures of tendon healing in research studies, we intend to use computed tomography (CT) with implanted radiopaque markers on the repaired ...tendon to measure tendon retraction following rotator cuff repair. In our small prior study, retraction at 1-year follow-up averaged 16.1± 5.3 mm and exceeded 10.0 mm in 12 of 13 patients, and thus tendon retraction appears to be a common clinical phenomenon. This study's objectives were to assess, using 5 longitudinal CT scans obtained over 1 year following rotator cuff repair, the variability in glenohumeral positioning because of pragmatic variations in achieving perfect arm repositioning and to estimate the associated measurement variability in bone-to-tendon marker length measurements.
Forty-eight patients underwent rotator cuff repair with intraoperative placement of radiopaque tendon markers at the repair site. All patients had a CT scan with their arms at the side on the day of surgery and at 3, 12, 26, and 52 weeks postoperatively. Glenohumeral position (defined by the orientation and distance of the humerus with respect to the scapula) and bone-to-tendon marker lengths were measured from each scan. Within-patient variation in glenohumeral position measurements was described by their pooled within-patient standard deviations (SDs), and variation in bone-to-tendon marker lengths by their standard errors of measurement (SEMs) and 95% confidence level minimally detectable distances (MDD95) and changes (MDC95).
The mean glenohumeral orientation from the 5 longitudinal CT scans averaged across the 48 patients was 12.6° abduction, 0.4° flexion, and –0.1° internal rotation. Within-patient SDs (95% confidence intervals) of glenohumeral orientation were 3.0° (2.7°-3.4°) in extension/flexion, 5.2° (4.6°-5.8°) in abduction/adduction, and 8.2° (7.3°-9.2°) in internal/external rotation. The SDs of glenohumeral distances were less than 1 mm in any direction. The estimated SEMs of bone-to-tendon lengths were consistent with a common value of 2.4 mm for any of the tendon markers placed across the repair, with MDD95 of 4.7 mm and MDC95 of 6.7 mm.
Apparent tendon retraction of 5 mm or more, when measured as the distance from a tendon marker's day of surgery location to its new location on a volumetrically registered longitudinal CT scan, may be considered above the usual range of measurement variation. Tendon retraction measured using implanted radiopaque tendon markers offers an objective and sufficiently reliable means for quantifying the commonly expected changes in structural healing following rotator cuff repair.
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