Dorsal Tilt of the Distal Radius Fracture Changes With Forearm Rotation When Measured on Radiographs

3D wrist imaging - Is it time for superman to retire?

Objectives

Computed tomography (CT) of the wrist may be challenged, due to patients' inability to extend the arm for a "Superman pose" resulting in increased radiation dose due to scatter. Alternative positions and less dose administering modalities such as 3D Cone-beam CT (CBCT) and single-shot CT could be considered. This phantom study aimed to estimate scatter radiation dose in different phantom positions using helical and single-shot CT and 3D CBCT.

Material and Methods

Wireless electronic dosimeters attached to the head and chest of an anthropomorphic phantom in various clinically relevant positions were used to measure scatter radiation. In helical CT, the following positions were used: Superman pose, semi-superman pose, wrist on the abdomen, and single-shot CT with the patient sitting in front of and behind the gantry. In 3D CBCT, the phantom was in a supine position with the arm extended laterally.

Results

Helical CT using the Superman pose resulted in a total scattered radiation dose of 64.8 µGy. The highest total dose (269.7 µGy) was obtained with the wrist positioned on the abdomen while the lowest total dose was achieved in single-shot CT with the phantom sitting behind the gantry with the forearm placed inside the gantry (3.2 µGy). The total dose in 3D CBCT was 171.1 µGy.

Conclusion

The commonly used semi-superman and wrist-on-abdomen positions in CT administer the highest scattered doses and should be avoided when either single-shot CT or 3D CBCT is available. Radiographers should carefully consider alternatives when a patient referred for wrist CT cannot comply with the Superman position.

The cost of perfection: An investigation into the unnecessary rejection of clinically acceptable lateral wrist imaging

INTRODUCTION

This study illustrates image rejection rates of the lateral wrist x-ray projection at a large, public teaching hospital. Rejected images were evaluated to determine the number of images that needed to be repeated based on the clinical indication. This study highlights the difference in subjective image-repeat decision-making skills existing between radiologists, experienced radiographers and junior radiographers.

METHODS

A retrospective review was conducted of all rejected lateral wrist x-ray images by a panel of three radiologists, three experienced radiographers and six junior radiographers. This review aimed to determine if rejected imaging met the consideration of the clinical indication and assumed appropriate acquisition of an orthogonal projection. A complement of images that had not been rejected were included in the review to create a blinded study.

RESULTS

The review demonstrated 85.8% of rejected images were deemed to meet clinical requirements according to radiologists. The experienced radiographers agreed with radiologists regarding 75.3% of images. Junior radiographers agreed with radiologists in 34.2% of cases. Junior radiographers were three times more likely to seek repeat imaging than the radiologists and experienced radiographers.

CONCLUSIONS

This review demonstrated a lateral wrist projection reject rate of 38.7% with unnecessary repeats according to clinical indications in 85.8% of cases. The review of experienced radiographers was comparable to radiologists; however, the difference in decision-making skills was evident in the junior radiographers. This highlights an alarming trend, should similar results be demonstrated at other health services and indicates an unnecessary burden to clinical practice. Inclusion of clinical reasoning for imaging and the need for repeat imaging is recommended for radiography training programs.

Accuracy of radiographic measurements of fracture-induced deformity in the distal radius

Background

Management of the distal radius fracture (DRF) is to some extent based on radiographic characterization of fracture displacement. It remains unclear, however, if the measurements used to quantify displacement are accurate.

Purpose

To quantify accuracy of two radiographic measurements: dorsal/volar tilt and fracture compression, measured indirectly as ulnar variance (UV), using radiostereometric analyses (RSA) as reference standard.

Material and Methods

Twenty-one fresh frozen non-fractured human cadaveric forearms (right = 11, left = 10) were thawed and eligible for inclusion. The forearms were mounted on a custom made platform that allowed for controlled forearm rotation, and they underwent two rounds of imaging (both rounds consisted of RSA and radiographs). In round one, the non-fractured forearms were radiographed. In round two, artificial DRF´s with compression and dorsal angulation were created and imaging procedures repeated. Change in tilt and UV between the non-fractured and later fractured forearms was defined as fracture-induced deformity. Deformity was measured radiographically and additionally calculated using RSA. Bland Altman analyses were used to estimate agreement between radiographically measured, and RSA calculated, fracture-induced deformity.

Results

Our results indicated that radiographs underestimate the amount of fracture-induced deformity. Mean measured differences (bias) in dorsal tilt deformity between radiographs and RSA were -2.5° for both observers. The corresponding values for UV were -1.4 mm and -1.5 mm.

Conclusion

Quantifying fracture-induced deformity on radiographs underestimated the actual deformity when compared to RSA calculated deformity. These findings suggest that clinicians, at least in part, base fracture management and potentially corrective surgery on inaccurate measurements.

Using virtual reality simulation for training practical skills in musculoskeletal wrist X-ray - A pilot study

OBJECTIVES

Using virtual reality (VR), students of radiography can practice acquisition and positioning of musculoskeletal radiographs and get immediate feedback on their performance within the simulator. The purpose of this study was to assess usability of a newly developed VR simulator and to explore self-perceived clinical readiness (SPCR) of radiography students before and after training acquisition of wrist radiographs in the VR simulator.

MATERIAL AND METHODS

A prospective methodology was applied where the students (n = 10) estimated their own SPCR in regard to acquisition of wrist radiographs pre- and post-VR training. A questionnaire on usability, realism, and educational value of the simulator was answered post-VR training. Usability and SPCR scores were calculated. The student's paired t-test was applied to explore the impact of VR training on SPCR.

RESULTS

The students (90%) reported that the simulator was realistic and they thought that it could contribute to learning. The pre- and post-SPCR scores were 75 (95% confidence interval [CI]: 54-96) and 77 (95% CI: 59-95), respectively. There was no significant difference (P = 0.4574) between the pre- and post-SPCR scores.

CONCLUSION

Results indicated that the concept of training acquisition and positioning of wrist radiographs in a VR simulator is feasible with positive feedback from the students. The SPCR scores improved slightly, although not statistically significant, after completion of the training session.

Observer agreement of volar tilt of the wrist is influenced by forearm rotation

Background

Dorsal/volar tilt is an important radiographic measurement commonly included in the treatment decision of distal radius fractures (DRFs). However, studies have shown that forearm positioning relative to rotation (i.e., supination and pronation) can affect the measured tilt value but with substantial interobserver variance.

Purpose

To examine whether interobserver agreement on radiographic tilt measurement is influenced by forearm rotation.

Material and Methods

We radiographed 21 cadaveric forearms at 5° rotational intervals between 15° supination and 15° pronation on lateral radiographs. A radiologist and a hand surgeon measured tilt in a blinded and randomized fashion. Bland-Altman analyses with bias and limits of agreement (LoA) were used to estimate interobserver agreement for forearms in all degrees of rotation, non-rotated forearms, supinated forearms, and pronated forearms.

Results

Interobserver agreement varied with forearm rotation. Bias (95% confidence interval [CI]; LoA) was -1.54° (95% CI: -2.53, -0.55; LoA: -13.46, 10.38) when measuring tilt on radiographs with all degrees of forearm rotation, and -1.48° (95% CI: -4.13, 1.17; LoA: -12.88, 9.92) when measuring tilt on true lateral 0° radiographs. When measuring on supinated and pronated radiographs, bias was -0.03° (95% CI: -1.35, 1.29; LoA: -8.34, 8.28) and -3.23° (95% CI: -5.41, -1.06; LoA: -16.90, 10.44), respectively.

Conclusion

Interobserver agreement on tilt was similar when comparing measurements made on true lateral radiographs to those made on the group with all degrees of forearm rotation. However, interobserver agreement improved with supination and worsened with pronation.

The lateral wrist radiograph - To retake or not to retake

INTRODUCTION

Patient positioning may impact diagnostic quality when obtaining radiographs of the musculoskeletal (MSK) system. Hence, knowledge on patient positioning, as seen in the radiograph, followed by informed adjusted retake if appropriate, is key when undertaking MSK radiographs. Forearm positioning is particularly important in lateral wrist radiographs where rotation impacts anatomic measurements. The purpose was to evaluate the accuracy of MSK and non-MSK radiographers' immediate assessments of wrist positioning including need for retake.

METHODS

A questionnaire including images of 18 lateral wrist radiographs and questions regarding positioning, i.e. forearm rotation and flexion of the wrist, were developed and distributed to radiographers worldwide via the European Federation of Radiographer Societies (EFRS) and the Research Hub at the European Congress of Radiology (ECR) 2021. Demographic data such as area of expertise, years of experience etc. were collected.

RESULTS

In total, 156 replies were included in the analyses. The inter-observer agreement of radiographers' assessment of the need for a retake was 47% (kappa = .25) and the intra-observer agreement was 81% (kappa = .62). Radiographers working with MSK radiography had more correct positioning assessments than radiographers who did not routinely obtain radiographs of the MSK system (p = 0.0003).

CONCLUSION

Results indicated that MSK radiographers are more consistent in assessment of the need for a retake in lateral wrist radiographs and more able to correctly judge positioning compared to non-MSK radiographers.

IMPLICATIONS FOR PRACTICE

Constant focus on image quality may lead to increased awareness and adherence to image criteria. Improved image quality will in turn improve the diagnostic value for the benefit of the patients potentially leading to better outcomes.