Location of the ovaries in children and efficacy of gonadal shielding in hip and pelvis radiography

BACKGROUND

Patients with hip disorders undergo multiple radiographic examinations, so gonadal radiation risk should be minimized. Inaccurate shield placement, including obscuring landmarks, has been widely reported, and some studies reported that covering the true pelvis was inappropriate to shield young girls' ovaries. However, no reports on ovaries in Asian patients identified on magnetic resonance imaging exist. We aimed to identify the location of the ovaries in Japanese children and assess the efficacy of gonadal shielding.

METHODS

Female patients aged ≤16 years who underwent magnetic resonance imaging for hip disorders that displayed at least one ovary were included. Sixty ovaries from 31 patients were classified into two age groups: <2 years and >2 years, and the ovaries' position was classified according to the following four zones on the anteroposterior pelvic radiograph: zone 1 (true pelvis) - area surrounded by the line of the anterior superior iliac spines, inner side walls of the ilium, and symphysis pubis; zone 2 - areas lateral to zone 1; zone 3 - sacral area superior to zone 1; and zone 4 - areas lateral to zone 3. The ovaries' position was analyzed according to age group.

RESULTS

Thirty-one ovaries in 16 patients were <2 years, and 29 ovaries in 15 patients were >2 years. Thirteen ovaries in the true pelvis, 18 ovaries in the false pelvis were <2 years, and 27 in the true pelvis and 2 in the false pelvis were in >2 years. In girls aged <2 years, most ovaries in the false pelvis were located in zone 3.

CONCLUSIONS

Girls aged >2 years mostly have their ovaries in the true pelvis, and ovaries in infants tend to be located superior to the true pelvis. Covering the true pelvis is plausible for shielding ovaries. Shields should be placed slightly more cranially than the true pelvis for infants.

Gonad shielding in pelvic radiography: modern optimised X-ray systems might allow its discontinuation

OBJECTIVE

As gonad shielding is currently under debate, this study evaluates the practice, from its introduction in about 1905 until today.

METHODS

The literature was searched for developments in shielding and insights into the effects of ionising radiation on gonads. Based on own pre-1927 dose reconstructions, reported doses after 1927, a 2015-report from the European Union and recent own measurements, the effects of technological evolution and optimisation on radiation dose and hereditary risk were assessed.

RESULTS

In the 1900s, gonad shielding was first applied to prevent male sterility, but was discontinued when instrumental developments led to reduced radiation doses. In the 1950s, concerns about hereditary risks intensified and gonad shielding was recommended again, becoming routine worldwide. Imaging-chain improvements over time were considerable: in 2018, the absorbed dose was 0.5% of its 1905 value for the testes and 2% for the ovaries, our optimised effective dose a factor five lower than the value corresponding to the current EU diagnostic reference level, and the reduction in detriment-adjusted risk by shielding less than 1 × 10-6 for women and 5 × 10-6 for men.

CONCLUSIONS

Assessment of pelvic doses revealed a large reduction in radiation risks facilitated by technological developments. Optimisation likewise contributed, but unfortunately, its potential was never adequately exploited. Today, using a modern and optimised X-ray system, gonad shielding can be safely discontinued for women. For men, there might be a marginal benefit, but potential negative side-effects may well dominate. Discontinuation of gonad shielding seems therefore justifiable.

The skin dose of pelvic radiographs since 1896

OBJECTIVES

To derive conversions of antiquated exposure data into modern equivalents and to apply these in the assessment of the skin dose of pelvic radiographs since 1896.

METHODS

The literature 1896-2018 was searched for implicit and explicit dose information. The early implicit dose data contained now obsolete descriptions of radiation quality and quantity for long since disappeared X-ray systems of limited efficiency. Converting the old information into modern specifications was achieved using contemporary data and computer simulations. Final dose calculations were done with modern software. Explicit radiation doses of later date reported in old quantities and units were adapted according to current recommendations.

RESULTS

For the period before 1927 conversion algorithms for spark gap data and penetrometer hardnesses to high voltage could be derived. Electrical and X-ray efficiencies of several old röntgen systems were determined. Together they allowed reconstruction of 53 doses. After 1927 doses were generally explicitly specified; 114 were retrieved. Although an enormous spread was observed, the average skin dose was reduced by a factor of about 400.

CONCLUSIONS

Antiquated exposure data were successfully used for dose reconstruction. Extreme dose variability was a constant. Efforts to cut down doses were effective as skin doses went down from sub-erythema values to about one milligray.

Computed tomography versus plain radiography assessment of acetabular fracture reduction is more predictive for native hip survivorship

INTRODUCTION

Computed tomography (CT) is more accurate than plain pelvic radiography (PXR) for evaluating acetabular fracture reduction. As yet unknown is whether CT-based assessment is more predictive for clinical outcome. We determined the independent association between reduction quality according to both methods and native hip survivorship following acetabular fracture fixation.

MATERIALS AND METHODS

Retrospectively, 220 acetabular fracture patients were reviewed. Reductions on PXR were graded as adequate or inadequate (0-1 mm or > 1 mm displacement) (Matta's criteria). For CT-based assessment, adequate reductions were defined as < 1 mm step and < 5 mm gap, and inadequate reductions as ≥ 1 mm step and/or ≥ 5 mm gap displacement. Predictive values and Kaplan-Meier hip survivorship curves were compared and risk factors for conversion to total hip arthroplasty (THA) were identified.

RESULTS

Mean follow-up was 8.9 years (SD 5.6, range 0.5-23.3 years), and 52 patients converted to THA (24%). Adequate reductions according to CT versus PXR assessment were associated with higher predictive values for native hip survivorship (92% vs. 82%; p = 0.043). Inadequate reductions were equally predictive for conversion to THA (33% for CT and 30% for PXR; p = 0.623). For both methods, survivorship curves of adequate versus inadequate reductions were significantly different (p = 0.030 for PXR, p < 0.001 for CT). Only age ≥ 50 years (p < 0.001) and inadequate reductions as assessed on CT (p = 0.038) were found to be independent risk factors for conversion to THA. Reduction quality as assessed on PXR was not found to be independently predictive for this outcome (p = 0.585).

CONCLUSION

Native hip survivorship is better predicted based on postoperative CT imaging as compared to PXR assessment. Predicting need for THA in patients with inadequate reductions based on both assessment methods remains challenging. While both PXR and CT-based methods are associated with hip survivorship, only an inadequate reduction according to CT assessment was an independent risk factor for conversion to THA.

Forensic age estimation through evaluation of the apophyseal ossification of the iliac crest in Western Chinese

The criminal age estimation procedures have gained greatest significance to date, a reliable age diagnostics may depend on data of skeletal maturation from different socioeconomic status. In order to establish the iliac crest apophysis as a possible criterion for forensic age estimation in a different socioeconomic status, and to examine the pace of ossification for the iliac crest apophysis in Western Chinese, one thousand seven hundreds and seventy-seven conventional pelvic radiographs relating to West China Han group routinely taken between January 2010 and June 2012 have been sighted. The data was analysed with separation of the sexes. The results indicated that stage 2a was last observed in females at the age of 17.00 and in males at the age of 18.01, stage 3a was first achieved in females at the age of 14.46 and in males at the age of 15.31, stage 4 was observed between 17.95 and 25.98 years for male and between 18.36 and 25.95 years for female. By comparison with previous studies, our research indicated that Western Chinese presents a delaying development for the iliac crest apophysis. Furthermore, the present study with eight stages of ossification for the iliac crest offers a valuable alternative method of estimation of 18 years of age for Western Chinese.