Underreported vertebral fractures in an Italian population: comparison of plain radiographs vs quantitative measurements

An overview of the performance of AI in fracture detection in lumbar and thoracic spine radiographs on a per vertebra basis

PURPOSE

Subtle spinal compression fractures can easily be missed. AI may help in interpreting these images. We propose to test the performance of an FDA-approved algorithm for fracture detection in radiographs on a per vertebra basis, assessing performance based on grade of compression, presence of foreign material, severity of degenerative changes, and acuity of the fracture.

METHODS

Thoracic and lumbar spine radiographs with inquiries for fracture were retrospectively collected and analyzed by the AI. The presence or absence of fracture was defined by the written report or cross-sectional imaging where available. Fractures were classified semi-quantitatively by the Genant classification, by acuity, by the presence of foreign material, and overall degree of degenerative change of the spine. The results of the AI were compared to the gold standard.

RESULTS

A total of 512 exams were included, depicting 4114 vertebra with 495 fractures. Overall sensitivity was 63.2% for the lumbar spine, significantly higher than the thoracic spine with 50.6%. Specificity was 96.7 and 98.3% respectively. Sensitivity increased with fracture grade, without a significant difference between grade 2 and 3 compression fractures (lumbar spine: grade 1, 52.5%; grade 2, 72.3%; grade 3, 75.8%; thoracic spine: grade 1, 42.4%; grade 2, 60.0%; grade 3, 60.0%). The presence of foreign material and a high degree of degenerative changes reduced sensitivity.

CONCLUSION

Overall performance of the AI on a per vertebra basis was degraded in clinically relevant scenarios such as for low-grade compression fractures.

Delay in diagnosis of thoracolumbar fractures

The time interval between the date of trauma and the diagnosis of vertebral column fractures hinders management and increases liability. We have examined the features and implications of this delay. 585 consecutive thoracolumbar fractures (2005-2016), were considered; 382 (65.30%) were males and 203 (34.70%) females. Mean age was 51 yr. Fall from a height (187; 31.97%), simple fall (147; 25.13%) and road accidents (111; 18.97%) were the most frequent causes of trauma. Physical exertion caused 8.38% (N=49). 142 patients (24.27%) were not diagnosed on the injury day (mean = 3.2 days). Delay was longer in females (mean = 5.5 vs. 2.7 days) and shorter in falls from a height (mean = 2.3) or road accidents (2.8). Mean age of diagnosed on the injury day differed from those diagnosed in the first month (49.2 vs 60.1). Plain X-ray signs were found in 7 misdiagnosed cases (46.6%). Delay was more frequent in low mineralization cases. Diagnostic delay of spine fractures is frequent. Some risk profiles can help to reduce it. Careful emergency X-ray examination is encouraged, as well as early magnetic resonance imaging in risk profiles.

Quality assurance of imaging techniques used in the clinical management of osteoporosis

Recent advances in the densitometric and imaging techniques involved in the management of osteoporosis are associated with increasing accuracy and precision as well as with higher exposure to ionising radiation. Therefore, special attention to quality assurance (QA) procedures is needed in this field. The development of effective and efficient QA programmes is mandatory to guarantee optimal image quality while reducing radiation exposure levels to the ALARA principle (as low as reasonably achievable). In this review article, the basic QA procedures are discussed for the techniques applied to everyday clinical practice.

New dual-energy X-ray absorptiometry equipment in the assessment of vertebral fractures: technical limits and software accuracy

OBJECTIVE

The aim of this study was to investigate software accuracy and influence of body mass index on image quality of Lunar iDXA (Lunar, Madison, WI, USA; software enCORE 12.0) in vertebral fracture (VFs) assessment.

MATERIALS AND METHODS

We enrolled 65 normal or overweight patients (group 1) and 64 obese patients (group 2) with indication for morphometric evaluation of the spine. Patients underwent iDXA, with scans performed in the standard manner by an expert technologist. Lateral images of the spine were subsequently evaluated by a musculoskeletal radiologist as the gold standard. Our analysis considered five points: vertebral bodies missed or not assessable or wrongly labeled on T4-L4 segment, diagnostic performance of the automatic morphometric point-positioning system in the detection of VFs, upgrading and downgrading of fractures, radiologist intervention rate, and BMI influence.

RESULTS

In group 1, 57/845 (6.7%) vertebral bodies and 34/832 (4.1%) in group 2 were not assessable-the upper thoracic spine. enCORE failed to recognize vertebral levels in 5.4% of the patients (7.7% in group 1 vs. 3.1% in group 2). On a lesion-based analysis sensitivity, specificity and accuracy of the software were 81.4, 93.8, and 93.1% in group 1 and 69.1, 88.3, and 86.7% in group 2, respectively. For 52.7% of the vertebrae in group 1 (51/8 upgraded/downgraded) and 70.0% in group 2 (96/26 upgraded/downgraded), a point correction was necessary and this changed the diagnosis respectively in 29.2 and 50.0% of the patients. Differences in diagnostic performance and point correction rate were significantly different between the two groups; however, BMI did not significantly affect vertebral level labeling and was correlated with a better visualization of the whole T4-L4 spine segment.

CONCLUSIONS

This study provides new and interesting information about the accuracy, reliability, and imaging quality provided by iDXA in the assessment of VFs.

Vertebral morphometry by dual-energy X-ray absorptiometry (DXA) for osteoporotic vertebral fractures assessment (VFA)

PURPOSE

This study was done to evaluate the diagnostic accuracy of dual-energy X-ray absorptiometry (DXA) compared with conventional radiography for identifying vertebral fractures.

MATERIALS AND METHODS

A total of 930 postmenopausal women underwent conventional radiography and DXA imaging of the spine. The images were evaluated by two expert skeletal radiologists using the semiquantitative (SQ) method for conventional radiography and the morphometric vertebral fracture assessment (VFA) for DXA.

RESULTS

The SQ method for radiography (SQ-Rx) analysed 99.1% of vertebrae, identifying 442 vertebral fractures; VFA analysed 97.5% vertebrae, detecting 420 vertebral fractures. Agreement between SQ-Rx and VFA reached 98.76%, and the κ-score was 0.96 [95% confidence interval (CI), 0.95-0.98]. Assessing the grading of vertebral fractures, agreement reached 97.5% and the κ-score was 0.841 (95% CI, 0.821-0.891). Considering SQ-Rx method as "gold standard", VFA had a sensitivity of 97.85 % and a specificity of 99.81%. The negative (NPV) and positive (PPV) predictive value for VFA were 99.83 % and 98.15%, respectively. Fractures were identified in 251 (27 %) and 242 (26 %) of patients on SQ-Rx and VFA, respectively. On a per-patient basis, the agreement between the two methods was 97% and the κ-score was 0.95 (95% CI, 0.920-0.968). The diagnostic parameters for VFA were 97.23% sensitivity, 98.86% specificity, 97.60% PPV and 98.84% NPV.

CONCLUSIONS

This study demonstrated that VFA with DXA may reach a high level of accuracy for diagnosing vertebral fractures, suggesting that VFA should be introduced in the screening of individuals with a risk of osteoporosis and in the follow-up of osteoporotic patients receiving treatment.