Bo Redder Mussmann

Agreement and precision of periprosthetic bone density measurements in micro-CT, single and dual energy CT.

The objective of this study was to test the precision and agreement between bone mineral density measurements performed in micro CT, single and dual energy computed tomography, to determine how the keV level influences density measurements and to assess the usefulness of quantitative dual energy computed tomography as a research tool for longitudinal studies aiming to measure bone loss adjacent to total hip replacements. Samples from 10 fresh‐frozen porcine femoral heads were placed in a Perspex phantom and computed tomography was performed with two acquisition modes. Bone mineral density was calculated and compared with measurements derived from micro CT. Repeated scans and dual measurements were performed in order to measure between‐ and within‐scan precision. Mean density difference between micro CT and single energy computed tomography was 72 mg HA/cm3. For dual energy CT, the mean difference at 100 keV was 128 mg HA/cm3 while the mean difference at 110–140 keV ranged from −84 to −67 mg HA/cm3 compared with micro CT. Rescanning the samples resulted in a non‐significant overall between‐scan difference of 13 mg HA/cm3. Bland–Altman limits of agreement were wide and intraclass correlation coefficients ranged from 0.29 to 0.72, while 95% confidence intervals covered almost the full possible range. Repeating the density measurements for within‐scan precision resulted in ICCs >0.99 and narrow limits of agreement. Single and dual energy quantitative CT showed excellent within‐scan precision, but poor between‐scan precision. No significant density differences were found in dual energy quantitative CT at keV‐levels above 110 keV.

Intra- and inter-observer agreement and reliability of bone mineral density measurements around acetabular cup: a porcine ex-vivo study using single- and dual-energy computed tomography

Background Periprosthetic bone loss is considered to be a potentially contributing factor in aseptic loosening of acetabular hip components, but no studies have shown this association. The lack of association might be caused by insufficient image quality because of metal artifacts and challenges in measuring bone density (BMD) in complex anatomic structures which might be overcome using dual-energy computed tomography (DECT). Purpose To test inter- and intra-observer agreement and reliability of in-house segmentation software measuring BMD adjacent to acetabular cup and to compare measurements performed with single-energy CT (SECT) and DECT in cemented and cementless cups. Material and Methods Twenty-four acetabular cups inserted in porcine hip specimens were scanned with SECT and DECT. Bone density was measured in a three-dimensional volume adjacent to the cup. Double measurements were performed. Results BMD derived from SECT was approximately four times higher than that of DECT. In both scan modes, intraclass correlation coefficient (ICC) was >0.90 with no differences between repeated measurements, except for uncemented cups where a statistically significant difference of 11 mg/cm3 was found with DECT. DECT showed narrower limits of agreement than SECT. Inter-observer analysis showed small differences. Conclusion BMD can be estimated with high intra- and inter-observer reliability with SECT and DECT around acetabular cups using custom software. The intra- and inter-observer agreement of DECT is superior to that of SECT and better in the cementless concept. Good intra- and inter-observer reliability can be obtained in both cemented and cementless cups using the segmentation software. SECT and DECT cannot be used interchangeably.

CT triage for lung malignancy: coronal multiplanar reformation versus images in three orthogonal planes.

Background Generation of multiplanar reformation (MPR) images has become automatic on most modern computed tomography (CT) scanners, potentially increasing the workload of the reporting radiologists. It is not always clear if this increases diagnostic performance in all clinical tasks. Purpose To assess detection performance using only coronal multiplanar reformations (MPR) when triaging patients for lung malignancies with CT compared to images in three orthogonal planes, and to evaluate performance comparison of novice and experienced readers. Material and Methods Retrospective study of 63 patients with suspicion of lung cancer, scanned on 64-slice multidetector computed tomography (MDCT) with images reconstructed in three planes. Coronal images were presented to four readers, two novice and two experienced. Readers decided whether the patients were suspicious for malignant disease, and indicated their confidence on a five-point scale. Sensitivity and specificity on per-patient basis was calculated with regards to a reference standard of histological diagnosis, and compared with the original report using McNemar’s test. Receiver operating characteristic (ROC) curves were plotted to compare the performance of the four readers, using the area under the curve (AUC) as figure of merit. Results No statistically significant difference of sensitivity and specificity was found for any of the readers when compared to the original reports. ROC analysis yielded AUCs in the range of 0.92–0.93 for all readers with no significant difference. Inter-rater agreement was substantial (kappa = 0.72). Conclusion Sensitivity and specificity were comparable to diagnosis using images in three planes. No significant difference was found between experienced and novice readers.

Optimizing chest x-rays in patients treated with the LUCAS chest compression system

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Bone density measurements adjacent to acetabular cups in total hip arthroplasty using dual-energy CT: an in vivo reliability and agreement study

Background Measuring bone mineral density (BMD) around acetabular prosthetic components with computed tomography (CT) is challenged by the complex anatomy and metal artifacts. Three-dimensional (3D) segmentation is required for the analysis, but it is usually not practically applicable on current CT workstations Purpose To test the between-scan agreement and reliability of custom segmentation software for BMD measurements adjacent to cemented and uncemented acetabular cups in dual-energy CT (DECT). Material and Methods Twenty-four male patients with total hip arthroplasty were scanned and rescanned using 130-keV virtual monochromatic DECT images. Hemispherical regions of interest were defined slice-by-slice and BMD was calculated around the acetabular cup using custom segmentation software. Results In the uncemented cup, the mean BMD was 153 mg/cm3 with a between-scan difference of 10 mg/cm3 (P < 0.0001). In the cemented cup, the mean BMD was 186 mg/cm3 with a between-scan difference of 6 mg/cm3 (P = 0.15). In both uncemented and cemented cups the intraclass correlation coefficient between repeated measurements was >0.95 and narrow Bland–Altman Limits of Agreement. Conclusion BMD can be measured with high absolute between-scan agreement and good reliability adjacent to acetabular cemented and uncemented cups using DECT and segmentation software.

Single- and dual-energy quantitative CT adjacent to acetabular prosthetic components: a reliability study

Purpose: To gather opinions of radiographers regarding the use of humour among students and professionals, and to apprehend possible positive and/or negative impacts of its use on the care relationship. Methods: Sample. Six hundred forty-one senior radiographers and 411 first, second or third year undergraduate radiographers, for a total sample of 1052 subjects from all over France. Material. Within a quantitative phase, both professionals radiographers and radiographers-in-training were assessed on several Likert-type scales involving concepts such as the functions of humour, and a second, qualitative phase based on open survey questions further focused on investigating the most salient concepts, notably within the senior radiographer sample. Results: Although radiographer apprentices saw the major benefits of humour in their relationships with patients (i.e. building a trust relationship, distraction technique), the senior radiographers put forward benefits especially regarding their colleagues or their own person (pleasant working environment, coping strategy during stressful events). Positive aspects of humour do prevail over the negative ones in both radiographer groups, but professionals emphasize the contextualized aspects of humour and warn that it may infringe on patients and their dignity. Conclusion: Considering humour as a personal and a professional value among the samples studied opens new perspectives on use of humour and its training within both institutional and educational contexts, preventing any possible harmful use.

Iceball fracture during CT guided Cryoablation of Renal Papillary Adenocarcinoma

Scientific Sessions – Oral presentations – Program Overview Everyday challenges in radiology 62nd Nordic Congress of Radiology & 23rd Nordic Congress of Radiography Program Overview Thursday June 29th Time Silfurberg Kaldalon Rima Moderator H. M. Thorisson K. Sigurdardottir H. Bjarnason 08:00-09:30 New standards for the MR safety organizational structure for MR sites worldwide

Microdose acquisition in adolescent leg length discrepancy using a low-dose biplane imaging system

Background Children with leg length discrepancy often undergo repeat imaging. Therefore, every effort to reduce radiation dose is important. Using low dose preview images and noise reduction software rather than diagnostic images for length measurements might contribute to reducing dose. Purpose To compare leg length measurements performed on diagnostic images and low dose preview images both acquired using a low-dose bi-planar imaging system. Material and Methods Preview and diagnostic images from 22 patients were retrospectively collected (14 girls, 8 boys; mean age, 12.8 years; age range, 10–15 years). All images were anonymized and measured independently by two musculoskeletal radiologists. Three sets of measurements were performed on all images; the mechanical axis lines of the femur and the tibia as well as the anatomical line of the entire extremity. Statistical significance was tested with a paired t-test. Results No statistically significant difference was found between measurements performed on the preview and on the diagnostic image. The mean tibial length difference between the observers was −0.06 cm (95% confidence interval [CI], −0.12 to 0.01) and −0.08 cm (95% CI, −0.21 to 0.05), respectively; 0.10 cm (95% CI, 0.02–0.17) and 0.06 cm (95% CI, −0.02 to 0.14) for the femoral measurements and 0.12 cm (95% CI, −0.05 to 0.26) and 0.08 cm (95% CI, −0.02 to 0.19) for total leg length discrepancy. ICCs were >0.99 indicating excellent inter- and intra-rater reliability. Conclusion The data strongly imply that leg length measurements performed on preview images from a low-dose bi-planar imaging system are comparable to measurements performed on diagnostic images.