Evaluation of MR-derived CT-like images and simulated radiographs compared to conventional radiography in patients with benign and malignant bone tumors

CT-like images based on T1-weighted gradient echo MRI sequences for the assessment of fractures of the hand and wrist compared to CT

OBJECTIVE

To evaluate the performance of a 3D T1-weighted gradient-echo (3D T1GRE) computed tomography (CT)-like magnetic resonance imaging (MRI) sequence for detecting and assessing wrist and hand fractures compared to conventional CT.

METHODS

Subjects with acute wrist or hand fracture in CT underwent additional 3 T MRI including a CT-like 3D T1GRE sequence and were compared to patients without fractures. Two radiologists assessed fracture morphology on both modalities according to the Arbeitsgemeinschaft Osteosynthese (AO) and graded image quality and diagnostic confidence on a 5-point Likert scale. Besides diagnostic test evaluation, differences in image quality and diagnostic confidence between CT-like MRI and CT were calculated using the Wilcoxon test. Agreement of AO classification between modalities and readers was assessed using Cohen's Kappa.

RESULTS

Twenty-eight patients with 43 fractures and 43 controls were included. Image quality (3D T1GRE 1.19 ± 0.37 vs. CT 1.22 ± 0.42; p = 0.65) and diagnostic confidence (3D T1GRE 1.28 ± 0.53 vs. CT 1.28 ± 0.55; p = 1.00) were rated excellent for both modalities. Regarding the AO classification, intra- (rater 1 and rater 2, κ = 0.89; 95% CI 0.80-0.97) and interrater agreement were excellent (3D T1GRE, κ = 0.82; 95% CI, 0.70-0.93; CT, κ = 0.85; 95% CI, 0.75-0.94). CT-like MRI showed excellent sensitivity, specificity and accuracy for fracture detection (reader 1: 1.00, 0.92, 0.96; reader 2: 0.98, 0.94, 0.96).

CONCLUSION

CT-like MRI is a comparable alternative to CT for assessing hand and wrist fractures, offering the advantage of avoiding radiation exposure.

Squamous papilloma involving the mandible: A case report and descriptive literature review

Squamous papilloma is a benign neoplasm that originates from the stratified squamous epithelium of the mucous membrane. Its principal etiological factor is human papillomavirus infection, with a predilection for manifesting within the oral cavity. Squamous papilloma predominantly affects regions on the palate, cheeks, lips and tongue. However, to the best of our knowledge, the occurrence of squamous papilloma within the confines of the mandible remains unreported hitherto. The present report documents a case of squamous papilloma involving the mandible who was managed at the First Affiliated Hospital of Sun Yat-sen University (Guangzhou, China) in January 2023. The patient underwent a series of recurrent jaw inflammations, manifesting with malignant imaging characteristics. Subsequent pathological analysis confirmed a diagnosis of papilloma in the jaw. The present report highlights the pivotal role of prolonged inflammation in the genesis of jaw squamous papilloma, prompting avenues for further investigation, including the potential of inflammation to induce aberrant cell growth, mediate cell interactions, orchestrate cytokine actions and influence stress mediators. In addition, the current study posits a plausible connection between persistent inflammation, compromised epithelial integrity and an increased likelihood of head and neck papilloma, particularly concerning human papillomavirus infection. This article delineates the clinical attributes of the uncommon manifestations of jaw papilloma and delves into the associated mechanisms, thereby contributing to an enhanced comprehension of jaw disorders. This comprehensive insight equips clinicians with a heightened knowledge base for more precise diagnosis and treatment of analogous cases.

Automatic detection, segmentation, and classification of primary bone tumors and bone infections using an ensemble multi-task deep learning framework on multi-parametric MRIs: a multi-center study

OBJECTIVES

To develop an ensemble multi-task deep learning (DL) framework for automatic and simultaneous detection, segmentation, and classification of primary bone tumors (PBTs) and bone infections based on multi-parametric MRI from multi-center.

METHODS

This retrospective study divided 749 patients with PBTs or bone infections from two hospitals into a training set (N = 557), an internal validation set (N = 139), and an external validation set (N = 53). The ensemble framework was constructed using T1-weighted image (T1WI), T2-weighted image (T2WI), and clinical characteristics for binary (PBTs/bone infections) and three-category (benign/intermediate/malignant PBTs) classification. The detection and segmentation performances were evaluated using Intersection over Union (IoU) and Dice score. The classification performance was evaluated using the receiver operating characteristic (ROC) curve and compared with radiologist interpretations.

RESULT

On the external validation set, the single T1WI-based and T2WI-based multi-task models obtained IoUs of 0.71 ± 0.25/0.65 ± 0.30 for detection and Dice scores of 0.75 ± 0.26/0.70 ± 0.33 for segmentation. The framework achieved AUCs of 0.959 (95%CI, 0.955-1.000)/0.900 (95%CI, 0.773-0.100) and accuracies of 90.6% (95%CI, 79.7-95.9%)/78.3% (95%CI, 58.1-90.3%) for the binary/three-category classification. Meanwhile, for the three-category classification, the performance of the framework was superior to that of three junior radiologists (accuracy: 65.2%, 69.6%, and 69.6%, respectively) and comparable to that of two senior radiologists (accuracy: 78.3% and 78.3%).

CONCLUSION

The MRI-based ensemble multi-task framework shows promising performance in automatically and simultaneously detecting, segmenting, and classifying PBTs and bone infections, which was preferable to junior radiologists.

CLINICAL RELEVANCE STATEMENT

Compared with junior radiologists, the ensemble multi-task deep learning framework effectively improves differential diagnosis for patients with primary bone tumors or bone infections. This finding may help physicians make treatment decisions and enable timely treatment of patients.

KEY POINTS

• The ensemble framework fusing multi-parametric MRI and clinical characteristics effectively improves the classification ability of single-modality models. • The ensemble multi-task deep learning framework performed well in detecting, segmenting, and classifying primary bone tumors and bone infections. • The ensemble framework achieves an optimal classification performance superior to junior radiologists' interpretations, assisting the clinical differential diagnosis of primary bone tumors and bone infections.

Comparing CT-Like Images Based on Ultra-Short Echo Time and Gradient Echo T1-Weighted MRI Sequences for the Assessment of Vertebral Disorders Using Histology and True CT as the Reference Standard

BACKGROUND

Several magnetic resonance (MR) techniques have been suggested for radiation-free imaging of osseous structures.

PURPOSE

To compare the diagnostic value of ultra-short echo time and gradient echo T1-weighted MRI for the assessment of vertebral pathologies using histology and computed tomography (CT) as the reference standard.

STUDY TYPE

Prospective.

SUBJECTS

Fifty-nine lumbar vertebral bodies harvested from 20 human cadavers (donor age 73 ± 13 years; 9 male).

FIELD STRENGTH/SEQUENCE

Ultra-short echo time sequence optimized for both bone (UTEb) and cartilage (UTEc) imaging and 3D T1-weighted gradient-echo sequence (T1GRE) at 3 T; susceptibility-weighted imaging (SWI) gradient echo sequence at 1.5 T. CT was performed on a dual-layer dual-energy CT scanner using a routine clinical protocol.

ASSESSMENT

Histopathology and conventional CT were acquired as standard of reference. Semi-quantitative and quantitative morphological features of degenerative changes of the spines were evaluated by four radiologists independently on CT and MR images independently and blinded to all other information. Features assessed were osteophytes, endplate sclerosis, visualization of cartilaginous endplate, facet joint degeneration, presence of Schmorl's nodes, and vertebral dimensions. Vertebral disorders were assessed by a pathologist on histology.

STATISTICAL TESTS

Agreement between T1GRE, SWI, UTEc, and UTEb sequences and CT imaging and histology as standard of reference were assessed using Fleiss' κ and intra-class correlation coefficients, respectively.

RESULTS

For the morphological assessment of osteophytes and endplate sclerosis, the overall agreement between SWI, T1GRE, UTEb, and UTEc with the reference standard (histology combined with CT) was moderate to almost perfect for all readers (osteophytes: SWI, κ range: 0.68-0.76; T1GRE: 0.92-1.00; UTEb: 0.92-1.00; UTEc: 0.77-0.85; sclerosis: SWI, κ range: 0.60-0.70; T1GRE: 0.77-0.82; UTEb: 0.81-0.92; UTEc: 0.61-0.71). For the visualization of the cartilaginous endplate, UTEc showed the overall best agreement with the reference standard (histology) for all readers (κ range: 0.85-0.93).

DATA CONCLUSIONS

Morphological assessment of vertebral pathologies was feasible and accurate using the MR-based bone imaging sequences compared to CT and histopathology. T1GRE showed the overall best performance for osseous changes and UTEc for the visualization of the cartilaginous endplate.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 2.

Advances in Imaging (Intraop Cone-Beam Computed Tomography, Synthetic Computed Tomography, Bone Scan, Low-Dose Protocols)

Spine surgery has seen a rapid advance in the refinement and development of 3-dimensional and nuclear imaging modalities in recent years. Cone-beam CT has proven to be a valuable tool for improving the accuracy of pedicle screw placement. The use of synthetic CT and low-dose CT have also emerged as modalities which allow for little to no radiation while streamlining imaging workflows. Bone scans also serve to provide functional information about bone metabolism in both the preoperative and postoperative monitoring phases.

Fast field echo resembling CT using restricted echo-spacing (FRACTURE) MR sequence can provide craniocervical region images comparable to a CT in dogs

Magnetic resonance imaging (MRI) is essential for evaluating cerebellar compression in patients with craniocervical junction abnormalities (CJA). However, it is limited in depicting cortical bone because of its short T2 relaxation times, low proton density, and organized structure. Fast field echo resembling a computed tomography (CT) scan using restricted echo-spacing (FRACTURE) MRI, is a new technique that offers CT-like bone contrast without radiation. This study aimed to assess the feasibility of using FRACTURE MRI for craniocervical junction (CCJ) assessment compared with CT and conventional MRI, potentially reducing the need for multiple scans and radiation exposure, and simplifying procedures in veterinary medicine. CT and MRI of the CCJ were obtained from five healthy beagles. MRI was performed using three-dimensional (3D) T1-weighted, T2-weighted, proton density-weighted (PDW), single echo-FRACTURE (sFRACTURE), and multiple echo-FRACTURE (mFRACTURE) sequences. For qualitative assessment, cortical delineation, trabecular bone visibility, joint space visibility, vertebral canal definition, overall quality, and artifacts were evaluated for each sequence. The geometrical accuracy, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were quantified. Both sFRACTURE and CT images provided significantly higher scores for cortical delineation and trabecular bone visibility than conventional MRI. Joint space visibility and vertebral canal definition were similar to those observed on CT images, regardless of the MR sequence. In the quantitative assessment, the distances measured on T2-weighted images differed significantly from those measured on CT. There were no significant differences between the distances taken using T1-weighted, PD-weighted, sFRACTURE, mFRACTURE and those taken using CT. T1-weighted and sFRACTURE had a higher SNR for trabecular bone than CT. The CNR between the cortical bone and muscle was high on CT and FRACTURE images. However, the CNR between the cortical and trabecular bones was low in mFRACTURE. Similar to CT, FRACTURE sequences showed higher cortical delineation and trabecular bone visibility than T2-weighted, T1-weighted, and PDW CCJ sequences. In particular, sFRACTURE provided a high signal-to-noise ratio (SNR) of the trabecular bone and a high CNR between the cortical bone and muscle and between the cortical and trabecular bones. FRACTURE sequences can complement conventional MR sequences for bone assessment of the CCJ in dogs.

Deep-learning-based image quality enhancement of CT-like MR imaging in patients with suspected traumatic shoulder injury

PURPOSE

To evaluate the diagnostic performance of CT-like MR images reconstructed with an algorithm combining compressed sense (CS) with deep learning (DL) in patients with suspected osseous shoulder injury compared to conventional CS-reconstructed images.

METHODS

Thirty-two patients (12 women, mean age 46 ± 14.9 years) with suspected traumatic shoulder injury were prospectively enrolled into the study. All patients received MR imaging of the shoulder, including a CT-like 3D T1-weighted gradient-echo (T1 GRE) sequence and in case of suspected fracture a conventional CT. An automated DL-based algorithm, combining CS and DL (CS DL) was used to reconstruct images of the same k-space data as used for CS reconstructions. Two musculoskeletal radiologists assessed the images for osseous pathologies, image quality and visibility of anatomical landmarks using a 5-point Likert scale. Moreover, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated.

RESULTS

Compared to CT, all acute fractures (n = 23) and osseous pathologies were detected accurately on the CS only and CS DL images with almost perfect agreement between the CS DL and CS only images (κ 0.95 (95 %confidence interval 0.82-1.00). Image quality as well as the visibility of the fracture lines, bone fragments and glenoid borders were overall rated significantly higher for the CS DL reconstructions than the CS only images (CS DL range 3.7-4.9 and CS only range 3.2-3.8, P = 0.01-0.04). Significantly higher SNR and CNR values were observed for the CS DL reconstructions (P = 0.02-0.03).

CONCLUSION

Evaluation of traumatic shoulder pathologies is feasible using a DL-based algorithm for reconstruction of high-resolution CT-like MR imaging.

Clinical feasibility of MRI-based synthetic CT imaging in the diagnosis of lumbar disc herniation: a comparative study

BACKGROUND

Computed tomography (CT) and magnetic resonance imaging (MRI) are indicated for use in preoperative planning and may complicate diagnosis and place a burden on patients with lumbar disc herniation.

PURPOSE

To investigate the diagnostic potential of MRI-based synthetic CT with conventional CT in the diagnosis of lumbar disc herniation.

MATERIAL AND METHODS

After obtaining prior institutional review board approval, 19 patients who underwent conventional and synthetic CT imaging were enrolled in this prospective study. Synthetic CT images were generated from the MRI data using U-net. The two sets of images were compared and analyzed qualitatively by two musculoskeletal radiologists. The images were rated on a 4-point scale to determine their subjective quality. The agreement between the conventional and synthetic images for a diagnosis of lumbar disc herniation was determined independently using the kappa statistic. The diagnostic performances of conventional and synthetic CT images were evaluated for sensitivity, specificity, and accuracy, and the consensual results based on T2-weighted imaging were employed as the reference standard.

RESULTS

The inter-reader and intra-reader agreement were almost moderate for all evaluated modalities (κ = 0.57-0.79 and 0.47-0.75, respectively). The sensitivity, specificity, and accuracy for detecting lumbar disc herniation were similar for synthetic and conventional CT images (synthetic vs. conventional, reader 1: sensitivity = 91% vs. 81%, specificity = 83% vs. 100%, accuracy = 87% vs. 91%; P < 0.001; reader 2: sensitivity = 84% vs. 81%, specificity = 85% vs. 98%, accuracy = 84% vs. 90%; P < 0.001).

CONCLUSION

Synthetic CT images can be used in the diagnostics of lumbar disc herniation.

Assessment of glenoid bone loss and other osseous shoulder pathologies comparing MR-based CT-like images with conventional CT

OBJECTIVES

To evaluate and compare the diagnostic performance of CT-like images based on a 3D T1-weighted spoiled gradient-echo sequence (T1 GRE), an ultra-short echo time sequence (UTE), and a 3D T1-weighted spoiled multi-echo gradient-echo sequence (FRACTURE) with conventional CT in patients with suspected osseous shoulder pathologies.

MATERIALS AND METHODS

Patients with suspected traumatic dislocation of the shoulder (n = 46, mean age 40 ± 14.5 years, 19 women) were prospectively recruited and received 3-T MR imaging including 3D T1 GRE, UTE, and 3D FRACTURE sequences. CT was performed in patients with acute fractures and served as standard of reference (n = 25). Agreement of morphological features between the modalities was analyzed including the glenoid bone loss, Hill-Sachs interval, glenoid track, and the anterior straight-line length. Agreement between the modalities was assessed using Bland-Altman plots, Student's t-test, and Pearson's correlation coefficient. Inter- and intrareader assessment was evaluated with weighted Cohen's κ and intraclass correlation coefficient.

RESULTS

All osseous pathologies were detected accurately on all three CT-like sequences (n = 25, κ = 1.00). No significant difference in the percentage of glenoid bone loss was found between CT (mean ± standard deviation, 20.3% ± 8.0) and CT-like MR images (FRACTURE 20.6% ± 7.9, T1 GRE 20.4% ± 7.6, UTE 20.3% ± 7.7, p > 0.05). When comparing the different measurements on CT-like images, measurements performed using the UTE images correlated best with CT.

CONCLUSION

Assessment of bony Bankart lesions and other osseous pathologies was feasible and accurate using CT-like images based on 3-T MRI compared with conventional CT. Compared to the T1 GRE and FRACTURE sequence, the UTE measurements correlated best with CT.

CLINICAL RELEVANCE STATEMENT

In an acute trauma setting, CT-like images based on a T1 GRE, UTE, or FRACTURE sequence might be a useful alternative to conventional CT scan sparing associated costs as well as radiation exposure.

KEY POINTS

• No significant differences were found for the assessment of the glenoid bone loss when comparing measurements of CT-like MR images with measurements of conventional CT images. • Compared to the T1 GRE and FRACTURE sequence, the UTE measurements correlated best with CT whereas the FRACTURE sequence appeared to be the most robust regarding motion artifacts. • The T1 GRE sequence had the highest resolution with high bone contrast and detailed delineation of even small fractures but was more susceptible to motion artifacts.

Magnetic resonance bone imaging: applications to vertebral lesions

MR bone imaging is a recently introduced technique, that allows visualization of bony structures in good contrast against adjacent structures, like CT. Although CT has long been considered the modality of choice for bone imaging, MR bone imaging allows visualization of the bone without radiation exposure while simultaneously allowing conventional MR images to be obtained. Accordingly, MR bone imaging is expected as a new imaging technique for the diagnosis of miscellaneous spinal diseases. This review presents several sequences used in MR bone imaging including black bone imaging, ultrashort/zero echo time (UTE/ZTE) sequences, and T1-weighted 3D gradient-echo sequence. We also illustrate clinical cases in which spinal lesions could be effectively demonstrated on MR bone imaging, performed in most cases using a 3D gradient-echo sequence at our institution. The lesions presented herein include degenerative diseases, tumors and similar diseases, fractures, infectious diseases, and hemangioma. Finally, we discuss the differences between MR bone imaging and previously reported techniques, and the limitations and future perspectives of MR bone imaging.

Zero Echo Time vs. T1-Weighted MRI for Assessment of Cortical and Medullary Bone Morphology Abnormalities Using CT as the Reference Standard

BACKGROUND

Conventional MR pulse sequences result in poor signal from low T2 cortical bone because the minimum achievable echo time is limited. A sequence resulting in improved bone contrast is desirable.

PURPOSE

To evaluate the image quality and diagnostic performance of grayscale inversion zero echo time imaging (GI-ZTE) and grayscale inversion T1-weighted imaging (GI-T1WI) compared with computed tomography (CT).

STUDY TYPE

Prospective.

SUBJECTS

A total of 50 patients with musculoskeletal tumors or tumor-like diseases of the lower extremities having MRI and CT studies.

FIELD STRENGTH/SEQUENCE

GI-T1WI and GI-ZTE sequences at 1.5 T.

ASSESSMENT

Assessed cortical and medullary bone morphology abnormalities using CT as the reference standard. Three radiologists scored the images quality and recorded nine metrics to assess the diagnostic performance.

STATISTICAL TESTS

Differences in image quality were calculated using the Wilcoxon signed-rank test. The intraclass correlation coefficient (ICC) was used to analyze the agreement of quantitative lesion parameters between CT and MR sequences, as well as the interobserver reliability. A P value <0.05 was considered statistically significant.

RESULTS

Image quality score was significantly higher for CT images than GI-TIWI images. Except for radiologist 3 [4(0) vs 4 (1)], there was no significant difference in scores between CT and GI-ZTE [radiologist 1: 4 (0) vs 4 (0), P = 0.133; radiologist 2: 4 (0) vs 4 (0), P = 0.085]. There was good-excellent agreement between both MR sequences and CT for size, lesion number, location, sclerotic rim, expanded shell, destruction pattern, and matrix mineralization for all radiologists (ICC: 0.636-1.000). The consistency of periosteal reaction and penetration of the cortex was fair to good (0.481-0.729) between GI-T1WI and CT and good to excellent between GI-ZTE and CT (0.682-0.852).

DATA CONCLUSIONS

GI-ZTE images had superior intermodality agreement with CT images and allowed visualization of more cortical bone detail than GI-T1WI images.

EVIDENCE LEVEL

1.

TECHNICAL EFFICACY

Stage 2.

Evaluation of a deep learning-based reconstruction method for denoising and image enhancement of shoulder MRI in patients with shoulder pain

OBJECTIVES

To evaluate the diagnostic performance of an automated reconstruction algorithm combining MR imaging acquired using compressed SENSE (CS) with deep learning (DL) in order to reconstruct denoised high-quality images from undersampled MR images in patients with shoulder pain.

METHODS

Prospectively, thirty-eight patients (14 women, mean age 40.0 ± 15.2 years) with shoulder pain underwent morphological MRI using a pseudo-random, density-weighted k-space scheme with an acceleration factor of 2.5 using CS only. An automated DL-based algorithm (CS DL) was used to create reconstructions of the same k-space data as used for CS reconstructions. Images were analyzed by two radiologists and assessed for pathologies, image quality, and visibility of anatomical landmarks using a 4-point Likert scale.

RESULTS

Overall agreement for the detection of pathologies between the CS DL reconstructions and CS images was substantial to almost perfect (κ 0.95 (95% confidence interval 0.82-1.00)). Image quality and the visibility of the rotator cuff, articular cartilage, and axillary recess were overall rated significantly higher for CS DL images compared to CS (p < 0.03). Contrast-to-noise ratios were significantly higher for cartilage/fluid (CS DL 198 ± 24.3, CS 130 ± 32.2, p = 0.02) and ligament/fluid (CS DL 184 ± 17.3, CS 141 ± 23.5, p = 0.03) and SNR values were significantly higher for ligaments and muscle of the CS DL reconstructions (p < 0.04).

CONCLUSION

Evaluation of shoulder pathologies was feasible using a DL-based algorithm for MRI reconstruction and denoising. In clinical routine, CS DL may be beneficial in particular for reducing image noise and may be useful for the detection and better discrimination of discrete pathologies. Assessment of shoulder pathologies was feasible with improved image quality as well as higher SNR using a compressed sensing deep learning-based framework for image reconstructions and denoising.

KEY POINTS

• Automated deep learning-based reconstructions showed a significant increase in signal-to-noise ratio and contrast-to-noise ratio (p < 0.04) with only a slight increase of reconstruction time of 40 s compared to CS. • All pathologies were accurately detected with no loss of diagnostic information or prolongation of the scan time. • Significant improvements of the image quality as well as the visibility of the rotator cuff, articular cartilage, and axillary recess were detected.

Ankle Sprains in Athletes: Current Epidemiological, Clinical and Imaging Trends

Purpose

Ankle injuries are frequent sports injuries. Despite optimizing treatment strategies during recent years, the percentage of chronification following an ankle sprain remains high. The purpose of this review article is, to highlight current epidemiological, clinical and novel advanced cross-sectional imaging trends that may help to evaluate ankle sprain injuries.

Methods

Systematic PubMed literature research. Identification and review of studies (i) analyzing and describing ankle sprain and (ii) focusing on advanced cross-sectional imaging techniques at the ankle.

Results

The ankle is one of the most frequently injured body parts in sports. During the COVID-19 pandemic, there was a change in sporting behavior and sports injuries. Ankle sprains account for about 16-40% of the sports-related injuries. Novel cross-sectional imaging techniques, including Compressed Sensing MRI, 3D MRI, ankle MRI with traction or plantarflexion-supination, quantitative MRI, CT-like MRI, CT arthrography, weight-bearing cone beam CT, dual-energy CT, photon-counting CT, and projection-based metal artifact reduction CT may be introduced for detection and evaluation of specific pathologies after ankle injury. While simple ankle sprains are generally treated conservatively, unstable syndesmotic injuries may undergo stabilization using suture-button-fixation. Minced cartilage implantation is a novel cartilage repair technique for osteochondral defects at the ankle.

Conclusion

Applications and advantages of different cross-sectional imaging techniques at the ankle are highlighted. In a personalized approach, optimal imaging techniques may be chosen that best detect and delineate structural ankle injuries in athletes.

Imaging of traumatic mandibular fractures in young adults using CT-like MRI: a feasibility study

OBJECTIVES

To assess and compare the diagnostic performance of CT-like images based on a three- dimensional (3D) T1-weighted spoiled gradient-echo sequence (3D T1 GRE) with CT in patients with acute traumatic fractures of the mandible.

MATERIALS AND METHODS

Subjects with acute mandibular fractures diagnosed on conventional CT were prospectively recruited and received an additional 3 T MRI with a CT-like 3D T1 GRE sequence. The images were assessed by two radiologists with regard to fracture localization, degree of dislocation, and number of fragments. Bone to soft tissue contrast, diagnostic confidence, artifacts, and overall image quality were rated using a five-point Likert-scale. Agreement of measurements was assessed using an independent t-test.

RESULTS

Fourteen subjects and 22 fracture sites were included (26 ± 3.9 years; 4 females, 10 males). All traumatic fractures were accurately detected on CT-like MRI (n = 22, κ 1.00 (95% CI 1.00-1.00)). There was no statistically significant difference in the assessment of the fracture dislocation (axial mean difference (MD) 0.06 mm, p = 0.93, coronal MD, 0.08 mm, p = 0.89 and sagittal MD, 0.04 mm, p = 0.96). The agreement for the fracture classification as well as the inter- and intra-rater agreement was excellent (range κ 0.92-0.98 (95% CI 0.96-0.99)).

CONCLUSION

Assessment of mandibular fractures was feasible and accurate using CT-like MRI based on a 3D T1 GRE sequence and is comparable to conventional CT.

CLINICAL RELEVANCE

For the assessment of acute mandibular fractures, CT-like MRI might become a useful alternative to CT in order to reduce radiation exposure particularly in young patients.

CT-like MR-derived Images for the Assessment of Craniosynostosis and other Pathologies of the Pediatric Skull

PURPOSE

To evaluate the diagnostic value of CT-like images based on a 3D T1-weighted spoiled gradient echo-based sequence (T1SGRE) for the visualization of the pediatric skull and the identification of pathologies, such as craniosynostosis or fractures.

METHODS

In this prospective study, 20 patients with suspected craniosynostosis (mean age 1.26 ± 1.38 years, 10 females) underwent MR imaging including the T1SGRE sequence and 2 more patients were included who presented with skull fractures (0.5 and 6.3 years, both male). Additionally, the skull of all patients was assessed using radiography or CT in combination with ultrasound. Two radiologists, blinded to the clinical information, evaluated the CT-like images. The results were compared to the diagnosis derived from the other imaging modalities and intraoperative findings. Intrarater and interrater agreement was calculated using Cohen's κ.

RESULTS

Of the 22 patients 8 had a metopic, 4 a coronal and 2 a sagittal craniosynostosis and 2 patients showed a complex combination of craniosynostoses. The agreement between the diagnosis based on the T1SGRE and the final diagnosis was substantial (Cohen's κ = 0.92, 95% confidence interval (CI) 0.77-1.00 for radiologist 1 and κ = 0.76, CI 0.51-1.00 for radiologist 2). Of the patients with fractures, one presented with a ping pong fracture and one with a fracture of the temporal bone. Both radiologists could identify the fractures using the T1SGRE.

CONCLUSION

The visualization of the pediatric skull and the assessment of sutures using a CT-like T1SGRE MR-sequence is feasible and comparable to other imaging modalities, and thus may help to reduce radiation exposure in pediatric patients. The technique may also be a promising imaging tool for other pathologies, such as fractures.

Emerging Technology in Musculoskeletal MRI and CT

This article provides a focused overview of emerging technology in musculoskeletal MRI and CT. These technological advances have primarily focused on decreasing examination times, obtaining higher quality images, providing more convenient and economical imaging alternatives, and improving patient safety through lower radiation doses. New MRI acceleration methods using deep learning and novel reconstruction algorithms can reduce scanning times while maintaining high image quality. New synthetic techniques are now available that provide multiple tissue contrasts from a limited amount of MRI and CT data. Modern low-field-strength MRI scanners can provide a more convenient and economical imaging alternative in clinical practice, while clinical 7.0-T scanners have the potential to maximize image quality. Three-dimensional MRI curved planar reformation and cinematic rendering can provide improved methods for image representation. Photon-counting detector CT can provide lower radiation doses, higher spatial resolution, greater tissue contrast, and reduced noise in comparison with currently used energy-integrating detector CT scanners. Technological advances have also been made in challenging areas of musculoskeletal imaging, including MR neurography, imaging around metal, and dual-energy CT. While the preliminary results of these emerging technologies have been encouraging, whether they result in higher diagnostic performance requires further investigation.

Synthetic CT in Musculoskeletal Disorders: A Systematic Review

ABSTRACT

Repeated computed tomography (CT) examinations increase patients' ionizing radiation exposure and health costs, making an alternative method desirable. Cortical and trabecular bone, however, have short T2 relaxation times, causing low signal intensity on conventional magnetic resonance (MR) sequences. Different techniques are available to create a "CT-like" contrast of bone, such as ultrashort echo time, zero echo time, gradient-echo, and susceptibility-weighted image MR sequences, and artificial intelligence. This systematic review summarizes the essential technical background and developments of ultrashort echo time, zero echo time, gradient-echo, susceptibility-weighted image MR imaging sequences and artificial intelligence; presents studies on research and clinical applications of "CT-like" MR imaging; and describes their main advantages and limitations. We also discuss future opportunities in research, which patients would benefit the most, the most appropriate situations for using the technique, and the potential to replace CT in the clinical workflow.

Evaluation of MR-derived simulated CT-like images and simulated radiographs compared to conventional radiography in patients with shoulder pain: a proof-of-concept study

Background

To evaluate the diagnostic value of MR-derived CT-like images and simulated radiographs compared with conventional radiographs in patients with suspected shoulder pathology.

Methods

3 T MRI of the shoulder including a 3D T1-weighted gradient echo sequence was performed in 25 patients (mean age 52.4 ± 18 years, 13 women) with suspected shoulder pathology. Subsequently a cone-beam forward projection algorithm was used to obtain intensity-inverted CT-like images and simulated radiographs. Two radiologists evaluated the simulated images separately and independently using the conventional radiographs as the standard of reference, including measurements of the image quality, acromiohumeral distance, critical shoulder angle, degenerative joint changes and the acromial type. Additionally, the CT-like MR images were evaluated for glenoid defects, subcortical cysts and calcifications. Agreement between the MR-derived simulated radiographs and conventional radiographs was calculated using Cohen’s Kappa.

Results

Measurements on simulated radiographs and conventional radiographs overall showed a substantial to almost perfect inter- and intra-rater agreement (κ = 0.69–1.00 and κ = 0.65–0.85, respectively). Image quality of the simulated radiographs was rated good to excellent (1.6 ± 0.7 and 1.8 ± 0.6, respectively) by the radiologists. A substantial agreement was found regarding diagnostically relevant features, assessed on Y- and anteroposterior projections (κ = 0.84 and κ = 0.69 for the measurement of the CSA; κ = 0.95 and κ = 0.60 for the measurement of the AHD; κ = 0.77 and κ = 0.77 for grading of the Samilson-Prieto classification; κ = 0.83 and κ = 0.67 for the grading of the Bigliani classification, respectively).

Conclusion

In this proof-of-concept study, clinically relevant features of the shoulder joint were assessed reliably using MR-derived CT-like images and simulated radiographs with an image quality equivalent to conventional radiographs. MR-derived CT-like images and simulated radiographs may provide useful diagnostic information while reducing the amount of radiation exposure.

Magnetic Resonance Imaging Versus Computed Tomography for Three-Dimensional Bone Imaging of Musculoskeletal Pathologies: A Review

Magnetic resonance imaging (MRI) is increasingly utilized as a radiation‐free alternative to computed tomography (CT) for the diagnosis and treatment planning of musculoskeletal pathologies. MR imaging of hard tissues such as cortical bone remains challenging due to their low proton density and short transverse relaxation times, rendering bone tissues as nonspecific low signal structures on MR images obtained from most sequences. Developments in MR image acquisition and post‐processing have opened the path for enhanced MR‐based bone visualization aiming to provide a CT‐like contrast and, as such, ease clinical interpretation. The purpose of this review is to provide an overview of studies comparing MR and CT imaging for diagnostic and treatment planning purposes in orthopedic care, with a special focus on selective bone visualization, bone segmentation, and three‐dimensional (3D) modeling. This review discusses conventional gradient‐echo derived techniques as well as dedicated short echo time acquisition techniques and post‐processing techniques, including the generation of synthetic CT, in the context of 3D and specific bone visualization. Based on the reviewed literature, it may be concluded that the recent developments in MRI‐based bone visualization are promising. MRI alone provides valuable information on both bone and soft tissues for a broad range of applications including diagnostics, 3D modeling, and treatment planning in multiple anatomical regions, including the skull, spine, shoulder, pelvis, and long bones.

MR Imaging of the Pelvic Bones: The Current and Cutting-Edge Techniques

This review presents an overview of the spectrum of the current and cutting-edge MRI techniques for pelvic bone imaging in clinical practice. The current MRI sequences and their advantages, disadvantages and usefullness in the imaging of this complex anatomical region are addressed. Finally, cutting-edge techniques are discussed, including susceptibility weighted MRI, ultrashort echo time MRI, zero echo time MRI and a deep learning-based multiparametric MRI technique named 'synthetic CT,' creating CT-like images without ionizing radiaton.

MAIN POINTS

GRE, SWI, UTE, ZTE MRI and synthetic CT sequences depict the cortical outline of the bones better in comparison to conventional MR images.MRI-based synthetic CT can create HU maps and allows for automated segmentation of pelvic bones.The current and cutting-edge MR techniques for bone imaging are complementary in the characterization of a variety of musculoskeletal disorders.

MRI-based synthetic CT of the lumbar spine: Geometric measurements for surgery planning in comparison with CT

PURPOSE

MRI is the imaging modality of choice for soft tissue-related spine disease. However, CT is superior to MRI in providing clear visualization of bony morphology. The purpose of this study is to test equivalency of MRI-based synthetic CT to conventional CT in quantitatively assessing bony morphology of the lumbar spine.

METHOD

A prospective study with an equivalency design was performed. Adult patients who had undergone MRI and CT of the lumbar spine were included. Synthetic CT images were generated from MRI using a deep learning-based image synthesis method. Two readers independently measured pedicle width, spinal canal width, neuroforamen length, anterior and posterior vertebral body height, superior and inferior vertebral body length, superior and inferior vertebral body width, maximal disc height, lumbar curvature and spinous process length on synthetic CT and CT. The agreement among CT and synthetic CT was evaluated using equivalency statistical testing.

RESULTS

Thirty participants were included (14 men and 16 women, range 20-60 years). The measurements performed on synthetic CT of pedicle width, spinal canal width, vertebral body height, vertebral body width, vertebral body length and spinous process length were statistically equivalent to CT measurements at the considered margins. Excellent inter- and intra-reader reliability was found for both synthetic CT and CT.

CONCLUSIONS

Equivalency of MRI-based synthetic CT to CT was demonstrated on geometrical measurements in the lumbar spine. In combination with the soft tissue information of the conventional MRI, this provides new possibilities in diagnosis and surgical planning without ionizing radiation.

3D MRI in Musculoskeletal Oncology

Advances in magnetic resonance imaging (MRI) technology now enable the feasible three-dimensional (3D) acquisition of images. With respect to the imaging of musculoskeletal (MSK) tumors, literature is beginning to accumulate on the use of 3D MRI acquisition for tumor detection and characterization. The benefits of 3D MRI, including general advantages, such as decreased acquisition time, isotropic resolution, and increased image quality, are not only inherently useful for tumor imaging, but they also contribute to the feasibility of more specialized tumor-imaging techniques, such as whole-body MRI, and are reviewed here. Disadvantages of 3D acquisition, such as motion artifact and equipment requirements, do exist and are also discussed. Although further study is needed, 3D MRI acquisition will likely prove increasingly useful in the evaluation of patients with tumors of the MSK system.

3D MRI with CT-like bone contrast - An overview of current approaches and practical clinical implementation

CT is the imaging modality of choice for assessment of 3D bony morphology but incurs the penalty of ionizing radiation. Improving the ability of 3D MRI to provide high-resolution images of cortical bone with CT-like bone contrast has been a focus of recent research. The ability of 3D MRI to deliver cortical bone information with similar diagnostic performance to CT would complement assessment of soft tissues and medullary bone from a single MRI examination, simplifying evaluation and obviating radiation exposure from additional CT. This article presents an overview of current 3D MRI approaches for imaging cortical bone with CT-like bone contrast including ultrashort echo time, zero echo time, T1-weighted gradient recalled echo, susceptibility-weighted imaging and deep learning techniques. We also discuss clinical implementation of an optimized stack-of-stars 3D gradient recalled echo pulse sequence (3D-Bone) on commercially available MRI scanners for rendering 3D MRI with CT-like bone contrast in our institutional practice.

Geometric accuracy of magnetic resonance imaging-derived virtual 3-dimensional bone surface models of the mandible in comparison to computed tomography and cone beam computed tomography: A porcine cadaver study

BACKGROUND

Providing accurate 3-dimensional virtual bone surface models is a prerequisite for virtual surgical planning and additive manufacturing in craniomaxillofacial surgery. For this purpose, magnetic resonance imaging (MRI) may be a radiation-free alternative to computed tomography (CT) and cone beam computed tomography (CBCT).

PURPOSE

The aim of this study was to assess the geometric accuracy of 3-dimensional T1-weighted MRI-derived virtual bone surface models of the mandible in comparison to CT and CBCT.

MATERIALS AND METHODS

Specimens of the mandible from porcine cadavers were scanned with (1) a 3-dimensional T1-weighted MRI sequence (0.6 mm isotropic voxel) optimized for bone imaging, (2) CT, and (3) CBCT. Cortical mandibular structures (n = 10) were segmented using semiautomated and manual techniques. Imaging-based virtual 3-dimensional models were aligned with a high-resolution optical 3-dimensional surface scan of the dissected bone (=ground truth) and global geometric deviations were calculated (mean surface distance [MSD]/root-mean-square distance [RMSD]). Agreement between the imaging modalities was assessed by equivalence testing and Bland-Altman analysis.

RESULTS

Intra- and inter-rater agreement was on a high level for all modalities. Global geometric deviations (MSD/RMSD) between optical scans and imaging modalities were 0.225 ± 0.020 mm/0.345 ± 0.074 mm for CT, 0.280 ± 0.067 mm/0.371 ± 0.074 mm for MRI, and 0.352 ± 0.076 mm/0.454 ± 0.071 mm for CBCT. All imaging modalities were statistically equivalent within an equivalence margin of ±0.3 mm, and Bland-Altman analysis indicated high agreement as well.

CONCLUSIONS

The results of this study indicate that the accuracy and reliability of MRI-derived virtual 3-dimensional bone surface models is equal to CT and CBCT. MRI may be considered as a reliable alternative to CT and CBCT in computer-assisted craniomaxillofacial surgery.

Magnetic resonance imaging as a diagnostic tool for periodontal disease: A prospective study with correlation to standard clinical findings-Is there added value?

AIM

To evaluate the correlation between standard clinical findings, radiographic (OPT) and magnetic resonance imaging (MRI) as well as to assess whether MRI is capable of providing additional information related to the severity and extent of periodontal disease.

METHODS

42 patients with generalized periodontitis received pre-interventional MRI scans. These were compared to MR images of a periodontal healthy control group (n = 34). The extent of the osseous oedema, detected by MRI, was set in correlation with clinical periodontitis-associated findings.

RESULTS

A highly significant correlation between bone oedema and clinical testings such as probing depth (p < 0.0001) and bleeding on probing (p < 0.0001) was revealed. The oedema exceeded the extent of demineralized bone. Patients with a positive BOP test showed a 2.51-fold increase in risk of already having a bone oedema around the respective tooth even if probing depth was ≤3 mm (logistic binary regression analysis, OR 2.51; 95% CI: 1.54-4.11; p < 0.0001).

CONCLUSION

MRI findings correlated with standard clinical findings, and MRI was able to depict intraosseous changes before any osseous defect had occurred.

Imaging of Bone Sarcomas and Soft-Tissue Sarcomas

BACKGROUND

 In the diagnosis of bone and soft-tissue sarcomas, the continuous advancement of various imaging modalities has improved the detection of small lesions, surgical planning, assessment of chemotherapeutic effects, and, importantly, guidance for surgery or biopsy.

METHOD

 This review was composed based on a PubMed literature search for the terms "bone sarcoma," "bone cancer" and "soft tissue sarcoma," "imaging," "magnetic resonance imaging", "computed tomography", "ultrasound", "radiography", and "radiomics" covering the publication period 2005-2020.

RESULTS AND CONCLUSION

 As discussed in this review, radiography, ultrasound, CT, and MRI all play key roles in the imaging evaluation of bone and soft-tissue sarcomas. In daily practice, advanced MRI techniques complement standard MRI but remain underused, as they are considered time-consuming, technically challenging, and not reliable enough to replace biopsy and histology. PET/MRI and radiomics have shown promise regarding the imaging of sarcomas in the future.

KEY POINTS

  · Radiographs remain crucial in diagnostic imaging algorithms for sarcomas.. · US is an initial imaging study for the evaluation of superficial soft-tissue tumors.. · The role of CT continues to evolve as new techniques emerge.. · MRI allows the noninvasive evaluation of soft-tissue, osseous, and articular structures.. · Machine learning methods could improve personalized selection of therapy for patients with sarcoma..

CITATION FORMAT

· Igrec J, Fuchsjäger MH. Imaging of Bone and Soft-Tissue Sarcomas. Fortschr Röntgenstr 2021; 193: 1171 - 1182.

Evaluation of cervical ossification of the posterior longitudinal ligament with 3D broadband IR-prepared ultrashort echo-time imaging: a pilot study

PURPOSE

We aimed to evaluate the feasibility of 3D broadband inversion-recovery-prepared ultrashort echo-time (3D IRP UTE) imaging for assessing ossification of the posterior longitudinal ligament (OPLL).

MATERIALS AND METHODS

The study consisted of 25 consecutive patients with cervical OPLL [13 women, 12 men; mean age 66.3 (47-84) years] who underwent CT, 3T conventional MR, and 3D IRP UTE imaging studies. Two readers independently assessed the 3D IRP UTE images for the type (mixed, continuous, circumscribed, segmental) and distribution of OPLL. All readers consensually assessed the diagnostic certainty of OPLL on conventional MR and 3D IRP UTE images by using a 3-point scale system. Interobserver and intermodality agreement was assessed by κ statistics. A Wilcoxon signed-rank test was used to evaluate the difference of diagnostic certainty between conventional MR and 3D IRP UTE imaging.

RESULTS

Interobserver and intermodality agreements were good (κ = 0.73) and excellent (κ = 0.81) for the OPLL type, and excellent (κ = 0.85) and good (κ = 0.76) for the assessment of the distribution of OPLL, respectively. The mean level of the diagnostic certainty of OPLL was significantly higher for 3D IRP UTE than conventional MR imaging (p = 0.002).

CONCLUSION

3D IRP UTE imaging may be useful for assessing OPLL.

CT-like images based on T1 spoiled gradient-echo and ultra-short echo time MRI sequences for the assessment of vertebral fractures and degenerative bone changes of the spine

Objectives

To evaluate the performance of 3D T1w spoiled gradient-echo (T1SGRE) and ultra-short echo time (UTE) MRI sequences for the detection and assessment of vertebral fractures and degenerative bone changes compared with conventional CT.

Methods

Fractures (n = 44) and degenerative changes (n = 60 spinal segments) were evaluated in 30 patients (65 ± 14 years, 18 women) on CT and 3-T MRI, including CT-like images derived from T1SGRE and UTE. Two radiologists evaluated morphological features on both modalities: Genant and AO/Magerl classifications, anterior/posterior vertebral height, fracture age; disc height, neuroforaminal diameter, grades of spondylolisthesis, osteophytes, sclerosis, and facet joint degeneration. Diagnostic accuracy and agreement between MRI and CT and between radiologists were assessed using crosstabs, weighted κ, and intraclass correlation coefficients. Image quality was graded on a Likert scale.

Results

For fracture detection, sensitivity, specificity, and accuracy were 0.95, 0.98, and 0.97 for T1SGRE and 0.91, 0.96, and 0.95 for UTE. Agreement between T1SGRE and CT was substantial to excellent (e.g., Genant: κ, 0.92 [95% confidence interval, 0.83–1.00]; AO/Magerl: κ, 0.90 [0.76–1.00]; osteophytes: κ, 0.91 [0.82–1.00]; sclerosis: κ, 0.68 [0.48–0.88]; spondylolisthesis: ICCs, 0.99 [0.99–1.00]). Agreement between UTE and CT was lower, ranging from moderate (e.g., sclerosis: κ, 0.43 [0.26–0.60]) to excellent (spondylolisthesis: ICC, 0.99 [0.99–1.00]). Inter-reader agreement was substantial to excellent (0.52–1.00), respectively, for all parameters. Median image quality of T1SGRE was rated significantly higher than that of UTE (p < 0.001).

Conclusions

Morphologic assessment of bone pathologies of the spine using MRI was feasible and comparable to CT, with T1SGRE being more robust than UTE.

Key Points

• Vertebral fractures and degenerative bone changes can be assessed on CT-like MR images, with 3D T1w spoiled gradient-echo–based images showing a high diagnostic accuracy and agreement with CT.

• This could enable MRI to precisely assess bone morphology, and 3D T1SGRE MRI sequences may substitute additional spinal CT examinations in the future.

• Image quality and robustness of T1SGRE sequences are higher than those of UTE MRI for the assessment of bone structures.

MRI-based Synthetic CT in the Detection of Structural Lesions in Patients with Suspected Sacroiliitis: Comparison with MRI

Background Evaluation of structural lesions in the sacroiliac (SI) joints can improve the accuracy for diagnosis of spondyloarthritis. However, structural lesions, such as erosions, are difficult to assess on routine T1-weighted MRI scans. Purpose To determine the diagnostic performance of MRI-based synthetic CT (sCT) in the depiction of erosions, sclerosis, and ankylosis of the SI joints compared with T1-weighted MRI, with CT as the reference standard. Materials and Methods A prospective study (clinical trial registration no. B670201837885) was performed from February 2019 to November 2019. Adults were referred from a tertiary hospital rheumatology outpatient clinic with clinical suspicion of inflammatory sacroiliitis. MRI and CT of the SI joints were performed on the same day. SCT images were generated from MRI scans using a commercially available deep learning-based image synthesis method. Two readers independently recorded if structural lesions (erosions, sclerosis, and ankylosis) were present on T1-weighted MRI, sCT, and CT scans in different reading sessions, with readers blinded to clinical information and other images. Diagnostic performance of sCT and T1-weighted MRI scans were analyzed using generalized estimating equation models, with consensus results of CT as the reference standard. Results Thirty participants were included (16 men, 14 women; mean age, 40 years ± 10 [standard deviation]). Diagnostic accuracy of sCT was higher than that of T1-weighted MRI for erosion (94% vs 86%, P = .003), sclerosis (97% vs 81%, P < .001), and ankylosis (92% vs 84%, P = .04). With sCT, specificity for erosion detection (96% [95% CI: 90, 98] vs 89% [95% CI: 81, 94], P = .01] and sensitivity for detection of sclerosis [94% [95% CI: 87, 97] vs 20% [95% CI: 10, 35], P < .001] and ankylosis (93% [95% CI: 78, 98] vs 70% [95% CI: 47, 87], P = .001) were improved. Conclusion With CT as the reference standard, synthetic CT of the sacroiliac joints has better diagnostic performance in the detection of structural lesions in individuals suspected of having sacroiliitis compared with routine T1-weighted MRI. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Fritz in this issue.

[The importance of radiology in bone sarcoma diagnostics : Initial and advanced diagnostics]

BACKGROUND

Reliable diagnostic assessment of malignant bone lesions remains a challenge in all the medical disciplines involved. The high incidence of benign (mainly pediatric) bone lesions needs to be distinguished from the rare malignant counterparts. If clinical presentation and patient history are unable to exclude a malignant tumour, adequate imaging of the affected region is necessary.

OBJECTIVES

This article focuses on giving implementable advice in dealing with problems and questions arising in the diagnostic process of treating patients with suspected or confirmed bone sarcoma. Also, follow-up recommendations from a radiological point of view are presented.

METHODS

Review and discussion of relevant literature against personal experiences in the medical imaging of patients with bone sarcomas.

RESULTS

Interpretation of projection radiographic images usually succeeds in assessing a bone tumour's dignity by evaluating periosteal reaction, the formation of a tumour matrix and consideration of the Lodwick classification. A current adaptation of the classic Lodwick classification incorporates diagnostic possibilities of more recent imaging techniques (magnetic resonance imaging (MRI), positron emission tomography (PET)) and is presented in this article. Plain radiographs are superseded by MRI as the primary imaging performed when depicting bone lesions with increasing frequency. The role of MRI in terms of primary diagnostics, staging, planning of biopsy tracts and tumour resections, evaluation of treatment response and follow-up are discussed. All diagnostic imaging techniques, including whole-body imaging methods, relevant in the diagnosis and therapy of bone sarcomas are presented in the sequence in which they appear during treatment.

CONCLUSIONS

Radiological imaging and expertise are important pillars in diagnosis and treatment of bone sarcomas. A variety of complementing imaging techniques provide a treatment-relevant basis significant for all medical disciplines involved.