Localizer sequences of magnetic resonance imaging accurately identify osteoporotic vertebral fractures

Why Should Radiologists Evaluate MR Localizer Sequences?

AIM

This study aimed to assess the diagnostic accuracy of magnetic resonance (MR) localizer sequences in the detection of spinal incidental findings.

MATERIALS AND METHODS

MR localizer sequence findings from 384 patients were reviewed retrospectively. The images were evaluated by an experienced radiologist. T2-weighted diagnostic sagittal and coronal images included in the abdominal images were taken as references.

RESULTS

Of the 384 patients, 170 were female and 214 were male. Pathology was detected in 63 of the patients. The findings were more common in male groups. These pathologies were spinal discopathy, metastases, hemangioma, angulation in the coccyx, and hemivertebra.

CONCLUSIONS

Although often overlooked, MR localizer images enable diagnosing additional pathologies in the spine. These are unsuspected but can be critical for patient management, reducing patient morbidity and mortality.

Readability of extraspinal organs on scout images of lumbar spine MRI according to different protocols

Background

Scout images of lumbar spine MRI often include the extraspinal organs, which are barely included in routine MRI and can be a potential cause of lumbar pain.

Purpose

To evaluate the readability of scout images for extraspinal organs in lumbar spine MRI according to different protocols.

Materials and methods

A total of 150 patients who underwent 1.5 T or 3 T lumbar spine MRI from March to September 2015 at three hospitals with different scout image protocols, were selected. Two radiologists independently reviewed the scout images to investigate whether exclusive diagnosis of major diseases involving the femoral head, femoral neck, sacroiliac joint, and kidneys was possible. Readability levels were divided into four categories: definitely, possibly, limited, and non-evaluable. The readability of scout images according to the protocols was compared using Chi-square test. Interobserver agreement for the readability level of scout images was assessed using weighted κ statistics.

Results

Of 150 patients, “definitely evaluable” cases classified by two readers were 50–62 (33.3–41.3%) for femoral head (κ = 0.63–0.71), 37–66 (24.7–44.0%) for femoral neck (κ = 0.41–0.48), 72–93 (48.0–62.0%) for sacroiliac joint (κ = 0.35–0.37), and 63–73 (42.0–48.7%) for kidneys (κ = 0.45–0.47). More than 50% of femoral heads were classified as readable (definitely or possible evaluable) cases by two readers with excellent interobserver agreement. The readability level of scout images was significantly different according to image protocols including the MRI sequence, number of coronal plane slices, and intersection gap of coronal plane slices (p≤0.015).

Conclusion

Scout images of lumbar spine MRI may be readable enough to rule out some major diseases of extraspinal organs. Standardization of the protocol will be needed to validate the potential role of scout images for screening extraspinal organs.

High bone marrow fat in patients with Cushing's syndrome and vertebral fractures

PURPOSE

The evaluation of skeletal fragility in Cushing's syndrome (CS) is a clinical challenge, since dual-energy X-ray absorptiometry (DXA) does not capture abnormalities in bone microstructure induced by glucocorticoid excess. Hypercortisolism was shown to increase bone marrow adiposity, but it is still unknown whether high bone marrow fat (BMF) as measured by vertebral magnetic resonance spectroscopy may predict fracture risk in this clinical setting. In this cross-sectional study, we evaluated the association between BMF and vertebral fractures (VFs) in patients with CS.

METHODS

Twenty patients (5 M, age 44 ± 13 years) with active CS were evaluated for morphometric VFs, lumbar spine BMF, and bone mineral density (BMD). Fifteen healthy volunteers (4 M, age 43 ± 12 years) acted as control group for BMF evaluation.

RESULTS

BMF was significantly higher in CS patients vs. controls (52.0% vs. 27.0%, p < 0.01), and was directly correlated with patients' age (p = 0.03), 24-hours urine-free cortisol (p = 0.03), midnight serum cortisol (p = 0.02), and serum CTX (p = 0.01). Patients with VFs (13 cases) showed significantly higher BMF vs. patients without VFs (65.0% vs. 24.0%, p = 0.03). Fractured patients with either normal BMD or osteopenia showed comparable BMF to fractured patients with either osteoporosis or low BMD for age (p = 0.71). When the analysis was restricted to patients with normal BMD or osteopenia, VFs were still significantly associated with higher BMF (p = 0.05).

CONCLUSIONS

This study provides a first evidence that vertebral adiposity may be a marker of hypercortisolism-induced skeletal fragility and measurement of spine BMF could have a role in the diagnostic work-up for the assessment of fracture risk in CS.

Role of lumbar spine signal intensity measurement by MRI in the diagnosis of osteoporosis in post-menopausal women

Background

Osteoporosis is a worldwide health problem and a common cause of bone fractures; the most common type of osteoporosis is post-menopausal type. MRI has a role in the diagnosis of osteoporosis and can be used as a screening tool, so the purpose of our study was to define a quantitative MRI-based score (M-score) for the detection of lumbar spine osteoporosis and to evaluate the correlation between lumbar spine signal intensity measured by MRI and BMD (bone mineral density) in post-menopausal women. Our case-control study involved 100 cases (50 old post-menopausal females as a case group and 50 healthy females as a control group of matched age). Both groups were subjected to history taking, dual-energy X-ray absorptiometry (DEXA), and conventional lumbar MRI. DEXA was performed for the lumbar spine and all scores (T-score, Z-score, BMD) were calculated. Lumbar MRI was performed (sagittal T1WI and T2WI) from L1–L4 levels. SNRL1–L4 and M-score were calculated from T1W images.

Results

All DEXA scores were significantly lower in post-menopausal females compared to the control group (P < 0.0001). Meanwhile, SNRL1–L4 and M-score were significantly higher among cases than controls (P < 0.0001). The diagnostic threshold of SNRL1–L4 and M-score for distinguishing osteoporotic from non-osteoporotic females was 104.5 for SNRL1–L4 with a sensitivity of 94%, specificity 60%, positive predictive values (PPV) 31%, and negative predictive values (NPV) 98%, and 3.5 for M-score with a sensitivity of 93.3%, specificity 83.5%, PPV 50%, and NPV 98.6%. SNRL1–L4 was negatively correlated with M-score (r = − 0.74, P < 0.0001), T-score (r = − 0.42, P < 0.0001), Z-score (r = − 0.32, P < 0.0001), and BMD (r = − 0.31, P < 0.0001). M-score was negatively correlated with T-score (r = − 0.48, P < 0.0001), Z-score (r = − 0.36, P < 0.0001), and BMD (r = − 0.37, P < 0.0001). M-score moderately agreed with T-score (κ = 0.5, P < 0.0001).

Conclusion

The MRI-based score (M-score) of the lumbar spine is an accurate quantitative method for distinguishing osteoporotic from non-osteoporotic females. M-score and SNRL1–L4 are significantly correlated with osteoporotic indices (T-score and BMD).

Whole spine localizers of magnetic resonance imaging detect unexpected vertebral fractures

BACKGROUND

Whole spine localizers (WS-loc) of magnetic resonance imaging (MRI) are performed for enumeration of the vertebrae but they can be also used for the evaluation of the spine.

PURPOSE

To assess the accuracy of fracture detection using WS-locs of MRI and compare the findings with standard high-resolution short tau inversion recovery (STIR) sequences, and to determine whether the review of WS-locs is useful and if additional information can be gained by assessing the thoracic spine section of the WS-locs.

MATERIAL AND METHODS

A total of 298 magnetic resonance (MR) examinations of the lumbar spine with WS-locs were evaluated. Two independent readers reviewed the images. In case of fracture detection, further characterization of the fracture was performed. To assess inter-reader agreement, unweighted Cohen's kappa with 95% confidence intervals (CI) and Phi coefficients were calculated.

RESULTS

The study sample included 187 female and 111 male patients (age range = 65-94 years; median age = 75.0 years). The WS-locs detected 42 fractures of the lumbar spine and 36 of the thoracic spine. Inter-reader agreement for fracture detection in the lumbar and thoracic spine was strong (K = 0.87, 95% CI = 0.78-0.95, Phi = 0.87, and K = 0.88, 95% CI = 0.79-0.96, Phi = 0.88, respectively).

CONCLUSION

WS-locs from MR examinations of the lumbar spine provide a good diagnostic tool for the detection and evaluation of unsuspected vertebral fractures. WS-locs show strong inter-reader agreement for fracture detection in the thoracic and lumbar spine.

Vertebral Fracture Identification as Part of a Comprehensive Risk Assessment in Patients with Osteoporosis

PURPOSE OF REVIEW

To review current evidence regarding the vertebral fracture prevalence, the accuracy of vertebral fracture identification on current imaging technologies, and the potential impact of vertebral fracture identification on fracture risk.

RECENT FINDINGS

Important new studies have clarified the features of prevalent vertebral fracture that most strongly predict incident fractures. Age- and sex-stratified estimates of vertebral fracture prevalence on densitometric lateral spine images in the US population are now available. The accuracy of densitometric vertebral fracture assessment, how computed tomography scans and other spinal images obtained for indications other than vertebral fracture assessment can be leveraged to detect prevalent vertebral fractures, and the potential impact of vertebral fracture assessment on patient and provider fracture risk management behavior have been clarified. Substantial progress has been made regarding screening strategies using lateral spine imaging to detect prevalent vertebral fracture in the older population. Further research regarding implementation of these strategies in clinical practice and their impact on clinical outcomes is needed.

Quantitative imaging techniques for the assessment of osteoporosis and sarcopenia

Bone and muscle are two deeply interconnected organs and a strong relationship between them exists in their development and maintenance. The peak of both bone and muscle mass is achieved in early adulthood, followed by a progressive decline after the age of 40. The increase in life expectancy in developed countries resulted in an increase of degenerative diseases affecting the musculoskeletal system. Osteoporosis and sarcopenia represent a major cause of morbidity and mortality in the elderly population and are associated with a significant increase in healthcare costs. Several imaging techniques are currently available for the non-invasive investigation of bone and muscle mass and quality. Conventional radiology, dual energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound often play a complementary role in the study of osteoporosis and sarcopenia, depicting different aspects of the same pathology. This paper presents the different imaging modalities currently used for the investigation of bone and muscle mass and quality in osteoporosis and sarcopenia with special emphasis on the clinical applications and limitations of each technique and with the intent to provide interesting insights into recent advances in the field of conventional imaging, novel high-resolution techniques and fracture risk.

Opportunistic Identification of Vertebral Fractures

Vertebral fractures are powerful predictors of future fracture, so, their identification is important to ensure that patients are commenced on appropriate bone protective or bone-enhancing therapy. Risk factors (e.g., low bone mineral density and increasing age) and symptoms (back pain, loss of height) may herald the presence of vertebral fractures, which are usually confirmed by performing spinal radiographs or, increasingly, using vertebral fracture assessment with dual-energy X-ray absorptiometry scanners. However, a large number (30% or more) of vertebral fractures are asymptomatic and do not come to clinical attention. There is, therefore, scope for opportunistic (fortuitous) identification of vertebral fractures from various imaging modalities (radiographs, computed tomography, magnetic resonance imaging, and radionuclide scans) performed for other clinical indications and which include the spine in the field of view, with midline sagittal reformatted images from computed tomography having the greatest potential for such opportunistic detection. Numerous studies confirm this potential for identification but consistently find underreporting of vertebral fractures. So, a valuable opportunity to improve the management of patients at increased risk of future fracture is being squandered. Educational training programs for all clinicians and constant reiteration, stressing the importance of the accurate and clear reporting of vertebral fractures ("you only see what you look for"), can improve the situation, and automated computer-aided diagnostic tools also show promise to solve the problem of this underreporting of vertebral fractures.

A new diagnostic score to detect osteoporosis in patients undergoing lumbar spine MRI

OBJECTIVES

Signal intensity of lumbar-spine at magnetic resonance imaging (MRI) correlates to bone mineral density (BMD). Our aim was to define a quantitative MRI-based score to detect osteoporosis on lumbar-spine MRI.

METHODS

After Ethics Committee approval, we selected female patients who underwent both lumbar-spine MRI and dual-energy X-ray absorptiometry (DXA) and a reference group of 131 healthy females (20-29 years) who underwent lumbar-spine MRI. We measured the intra-vertebral signal-to-noise ratio in L1-L4. We introduced an MRI-based score (M-score), on the model of T-score. M-score diagnostic performance in diagnosing osteoporosis was estimated against DXA using receiver operator characteristic (ROC) analysis.

RESULTS

We included 226 patients (median age 65 years), 70 (31%) being osteoporotic at DXA. MRI signal-to-noise ratio correlated to BMD (r = -0.677, P < 0.001). M-score negatively correlated to T-score (r = -0.682, P < 0.001). Setting a 90%-specificity, an M-score threshold of 5.5 was found, distinguishing osteoporosis from non-osteoporosis (sensitivity 54%; ROC AUC 0.844). Thirty-one (14%) patients had a fragility fracture, with osteoporosis detected in 15 (48%) according to M-score and eight (26%) according to T-score (P = 0.016).

CONCLUSIONS

M-score obtained on lumbar spine MRI is a quantitative method correlating with osteoporosis. Its diagnostic value remains to be demonstrated on a large prospective cohort of patients.

KEY POINTS

• M-score is a quantitative score potentially screening osteoporosis on lumbar-spine MRI; • This method showed good intra- and inter-reader reproducibility; • M-score may be used for identifying patients who should undergo DXA.

Bone metabolic changes during pregnancy: a period of vulnerability to osteoporosis and fracture

Changes in bone density and bone markers suggest that pregnancy is associated with deterioration of bone mass in the mother. The metabolism of calcium resets to allow for the needs imposed by the building of the fetal skeleton. The fetus contributes to the process through the output of regulators from the placenta. Understanding of the whole process is limited, but some changes are unambiguous. There is an increase in the circulating levels of vitamin D, but its functional impact is unclear. Fetal parathyroid hormone (PTH) and PTH-related peptide (PTHrp) play an indirect role through support of a calcium gradient that creates hypercalcemia in the fetus. Placental GH, which increases up to the end of pregnancy, may exert some anabolic effects, either directly or through the regulation of the IGF1 production. Other key regulators of bone metabolism, such as estrogens or prolactin, are elevated during pregnancy, but their role is uncertain. An increase in the ratio of receptor activator of nuclear factor kappa B ligand (RANKL) to osteoprotegerin (OPG) acts as an additional pro-resorbing factor in bone. The increase in bone resorption may lead to osteoporosis and fragility fracture, which have been diagnosed, although rarely. However, the condition is transitory as long-term studies do not link the number of pregnancies with osteoporosis. Prevention is limited by the lack of identifiable risk factors. When fractures are diagnosed, rest, analgesics, or, when indicated, orthopedic intervention have demonstrated efficacy. Systemic treatment with anti-osteoporotic drugs is effective, but the potential harm to the fetus imposes caution in their use.