Assessment of osteopenia from spine radiographs using two different methods: the Chingford Study

Towards the diagnosis of osteoporosis - contributions from coincidental diagnostic imaging findings in chiropractors' practice

BACKGROUND

Osteoporosis is significantly associated with fractures and burdens the health of especially older people. Osteoporotic fractures cause pain, disability, and increased mortality. Early diagnosis of osteoporosis allows earlier initiation of treatment, thereby reducing the risk of osteoporotic fractures. Chiropractors encounter potential osteoporotic patients daily, and perform radiological evaluation of these and other patients, including evaluation of X-rays done for other purposes than osteoporosis. Therefore, chiropractors may identify vertebral fractures, vertebral deformity or osteopenia not otherwise suspected or recorded.

METHODS

This study examines procedures available to the chiropractor to describe conventional X-rays with the focus of osteoporosis related findings. We review the indications for radiological examination in chiropractic practice, and in the realm of osteoporosis we describe radiological methods available for examination of conventional radiographs, and the necessity of inter-disciplinary communication.

RESULTS

National guidelines are available regarding referral for X-rays in chiropractic practice. Standardized protocols ensure image acquisition of the highest quality in the chiropractors' radiological department. Conventional X-ray examination is not indicated on clinical suspicion of osteoporosis alone, as bone mineral density testing is the diagnostic test. Radiological assessment of all available X-rays of patients above the age of 50 years should include evaluation of the bone quality, and hip and vertebral fracture assessment. The Singh index, Genant Semi-Quantitative tool (GSQ), and Algorithm-Based Qualitative method (ABQ) should be used consistently during interpretation. Referral for additional imaging and evaluation should be prompt and systematic when needed.

CONCLUSIONS

This article presents an overview of evidence-based radiological procedures for the purpose of promoting early diagnosis of osteoporosis. We present recommendations to the clinicians where we propose an opportunistic evaluation of X-rays, done for any reason, which include systematic evaluation of bone quality, presence of hip and vertebral fractures, and vertebral deformation of all patients above the age of 50 years. Detailed referral to healthcare professionals for further diagnostic evaluation is performed when needed. Consistent, high-quality radiological procedures in chiropractic practices could feasibly contribute to the timely diagnosis of osteoporosis, ultimately minimizing the impact of osteoporosis-related complications on patients' health.

DicomAnnotator: a Configurable Open-Source Software Program for Efficient DICOM Image Annotation

Modern, supervised machine learning approaches to medical image classification, image segmentation, and object detection usually require many annotated images. As manual annotation is usually labor-intensive and time-consuming, a well-designed software program can aid and expedite the annotation process. Ideally, this program should be configurable for various annotation tasks, enable efficient placement of several types of annotations on an image or a region of an image, attribute annotations to individual annotators, and be able to display Digital Imaging and Communications in Medicine (DICOM)-formatted images. No current open-source software program fulfills these requirements. To fill this gap, we developed DicomAnnotator, a configurable open-source software program for DICOM image annotation. This program fulfills the above requirements and provides user-friendly features to aid the annotation process. In this paper, we present the design and implementation of DicomAnnotator. Using spine image annotation as a test case, our evaluation showed that annotators with various backgrounds can use DicomAnnotator to annotate DICOM images efficiently. DicomAnnotator is freely available at https://github.com/UW-CLEAR-Center/DICOM-Annotator under the GPLv3 license.

Radiographic characteristics on conventional radiographs after posterior lumbar interbody fusion: comparative study between radiotranslucent and radiopaque cages

The problem of determining solidity of a fused spinal segment still remains. Our purpose is to evaluate radiographic findings after posterior lumbar interbody fusion (PLIF) with cages and estimate their relative value in judging fusion status. Radiographic follow-up was performed in patients after PLIF with cages of either radiotranslucent or radiopaque material. Conventional radiographs were obtained 6 weeks, 3 and 6 months, and then yearly after surgery for spinal instability for 64 patients. We differentiated between uncertain (increased density within the cage, increase of sclerotic endplates, and posterolateral fusion) and definite (trabecular continuous bone bridging within the implant and periimplant new bone formation with bridging of the intervertebral space) fusion signs. A fusion rate of 51.5% after 12 months, 61.4% after 24 months, 66.7% after 36 months, and 77.8% after 48 months postoperatively was found. We found only a slight, nonsignificant correlation between radiographic fusion and patient-assessed clinical outcome. There is evidence that radiographic fusion criteria occur in a specific chronologic order. The interpretation of fusion status is notably impaired by the use of radiopaque cages. Criteria to standardize the interpretation and evaluation of radiographic findings after PLIF are discussed.

Radiographic spinal profile changes induced by cage design after posterior lumbar interbody fusion preliminary report of a study with wedged implants

STUDY DESIGN

A prospective comparative radiographic study between two geometrically varying implants utilized in single-level posterior lumbar interbody fusion (PLIF) was performed.

OBJECTIVE

The aim of this study was to determine the influence of 4 degrees wedged cages on postoperative lateral lumbar spinal profile.

SUMMARY OF BACKGROUND DATA

The biomechanical and clinical importance of realigning the sagittal lumbar profile in surgical management of spinal instabilities is known. Wedged cages are therefore increasingly attaining popularity in PLIF. As yet the significance of wedged implants on postoperative sagittal spinal profile has not been assessed.

METHODS

Forty patients were randomly assigned to two equal-sized groups. In one group rectangular cages and in the second group cages with a wedged design and an inclination of 4 degrees were implanted. Quantitative assessment of the lumbar spinal profile on standing neutral lateral radiographs was performed before surgery as well as 6 weeks and 12 months after surgery. Results were statistically compared.

RESULTS

A significant improvement of lumbar sagittal profile after use of 4 degrees wedged compared with nonwedged cages was not found. The greatest effect on lumbar profile and segmental lordosis was observed in fusion of segment L4-L5 with 4 degrees wedged cages.

CONCLUSIONS

These results show that normal sagittal alignment after single-level lumbar fusion can be achieved with rectangular and 4 degrees wedged cages. Although results after utilization of 4 degrees wedged cages do not significantly differ, these implants offer the surgeon one more sizing variation with which physiologic lumbar lordosis may be attained. The biomechanical implications of wedged implants on the rigidity of a fused segment remain to be analyzed.

Morphometric dual-energy X-ray absorptiometry of the spine: report of a large series and correlation with axial bone mineral density

We studied vertebral morphometry and its relation to bone mineral density (BMD) in normal Brazilian women (n = 605). All women (age 22-97 years) were ambulatory and healthy. A lateral spine scan was done for morphometric X-ray absorptiometry using an imaging densitometer. In 429 of these women, BMD of the spine and proximal femur also were measured using dual-energy X-ray absorptiometry. All women were white with mean (+/- 1 SD) age of 53.7 (+/- 9.5) years. About 21% of the women over 50 years had a T score for spine BMD lower than -2.5 SD, and 7% had a femoral neck BMD below this osteoporosis threshold. Vertebral heights (anterior, HA; middle, HM; and posterior, HP) and ratios (HA/HP and HM/HP) were assessed. There was no systematic difference between younger (20-49 years) and older (50+ years) women in heights or ratios. The vertebral heights were normalized for those observed in each individual case for the L2-L4 sequence. This normalization was adequate for all vertebral heights; the Z score averaged about +0.1. The average Z score for HA/HP was +0.01, but that for the HM/HP was -0.72, indicating that the latter ratio might differ from the reference population used (white American and European women). We observed a small positive correlation between vertebral heights and spine or femur BMD, but this was due entirely to the influence of body size on BMD. On a group basis, the HM/HP showed a significant association with axial BMD; the 1 SD difference between the lowest and highest quartile was associated with a difference of 8-15% (0.5-1.0 SD) in axial BMD.

Radiation exposure in bone mineral density assessment

Osteoporosis is a systematic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue which leads to diminished biomechanical competence of the skeleton and low-trauma or atraumatic fractures. Due to increased awareness of the impact of osteoporosis on the elderly population, the use of bone densitometric techniques is becoming more widespread. Considerable progress has been made in the development of non-invasive methods for the assessment of the skeleton. While DXA and QCT are commonly used techniques, the popularity of other approaches such as RA, SXA and QUS is gaining grounds. QCT has an advantage over the other techniques in its ability to measure the true volumetric density of trabecular or cortical bone. We therefore present an overview of these current techniques for bone mineral density (BMD) measurements. In the second section we discuss the radiation doses incurred in BMD measurements by patients and methods for reducing patient and staff radiation exposure are given. Studies of radiation dose to patient from DXA confirms that patient dose is small (0.08-4.6 muSv) compared to that given by many other investigations involving ionizing radiation. Fan beam technology with increased resolution has resulted in increase patient dose radiation dose (6.7-31 muSv) but this is still relatively small. Carrying vertebral morphometry using DXA also incurs less radiation dose (< 60 muSv) than standard lateral radiographs QCT has radiation dose (25-360 muSv) comparable to simple radiological examination such as chest X-ray but lower than imaging CT. Radiation dose from other techniques such as RA and SXA are in the same order of magnitude as pencil beam DXA. For pencil beam DXA and SXA systems the time average dose to staff from scatter is very low even with the operator sitting as close as 1 m from the patient during measurement. However the scatter dose from fan beam DXA systems is considerable higher and approaches limits set by regulator bodies for occupational exposure.

Exercise-induced loss of bone density in athletes

In athletes, the rarely identified malady of osteoporosis differs from other chronic effects of exercise. The most obvious difference is that hormonal imbalance leads to compensatory mechanisms that in turn lead to osteoporosis and increased incidence of fracture. Most research on this subject has dealt with women, because hormonal imbalances in women are easier to detect than those in men. Endurance athletes are known to have decreased levels of sex hormones, which can cause physiologic changes that lead to bone loss. This may result in relative osteoporosis despite the loading of the bone during exercise, which would normally increase bone mineral density. Premature osteoporosis may be irreversible, causing young athletes to become osteoporotic at an earlier age and have an increased risk of fracture later in life.

Which vertebrae should be assessed in diagnosing osteoporosis by plain radiography? Comparative study of radiographic findings and bone mineral density measured by dual energy X-ray absorptiometry

In 1990, the Ministry of Health and Welfare of Japan advocated a criterion for the diagnosis radiographic bone atrophy in lumbar vertebrae. We carried out a comparative study of this criterion (i.e. , radiographic bone atrophy grading) and bone mineral density measured by posteroanterior and lateral dual energy X-ray absorptiometry. We investigated the second to fourth lumbar vertebrae of 47 postmenopausal women (mean age, 67.2 years; range, 57-82 years), to determine which vertebra would most accurately indicate osteoporosis. A significant difference in bone mineral density (P < 0.01) was found between each grade of radiographic bone atrophy in all of the second, third, and fourth vertebrae examined. The highest correlation (r = 0.714) was found between the radiographic grades and the bone mineral density on lateral dual energy X-ray absorptiometry of the third lumbar vertebrae. Our visual determinations were dependable, radiographic and a examination of the third lumbar vertebra rather than that of other lumbar vertebrae was more helpful for the detection of radiographic bone atrophy. Plain radiographic film can provide a rough estimation of bone atrophy.

Observer variation in plain radiography of the lumbosacral spine

In this study, interobserver and intraobserver variations in the interpretation of plain radiographs of the lumbosacral spine were evaluated. Three radiologists independently interpreted the radiographs from 200 consecutive outpatients, aged 13-93 years, mostly referred from general practitioners. Interobserver agreement was best for vertebral fractures, osteopenia, spondylolisthesis at L5-S1, lumbosacral junctional vertebra, reduced disc height at L4-S1 and osteophytes at L2-S1 (kappa 0.61-0.95), and poorest for spina bifida of S1, degenerative spondylolisthesis and facet joint arthrosis at T12-L4, sacroiliac joint arthrosis, narrow central spinal canal, film quality, and for decisions concerning evaluation of facet joints and spinal canal (kappa < 0.34). For several diagnoses, the number of abnormal findings differed significantly between observers (p < 0.05, McNemar's test), indicating different diagnostic thresholds. Intraobserver agreement in 36 reevaluated patients was fair to excellent for almost all variables (kappa > 0.46). Although some diagnoses related to low back pain were quite consistently evaluated, the substantial disagreement on many findings should alert clinicians and radiologists against overestimating the validity and usefulness of the examinations. To improve diagnostic consistency, it is important to reduce variation caused by different thresholds for abnormality.