Soft tissue tumor imaging in adults: European Society of Musculoskeletal Radiology-Guidelines 2023-overview, and primary local imaging: how and where?

OBJECTIVES: Early, accurate diagnosis is crucial for the prognosis of patients with soft tissue sarcomas. To this end, standardization of imaging algorithms, technical requirements, and reporting is therefore a prerequisite. Since the first European Society of Musculoskeletal Radiology (ESSR) consensus in 2015, technical achievements, further insights into specific entities, and the revised WHO-classification (2020) and AJCC staging system (2017) made an update necessary. The guidelines are intended to support radiologists in their decision-making and contribute to interdisciplinary tumor board discussions. MATERIALS AND METHODS: A validated Delphi method based on peer-reviewed literature was used to derive consensus among a panel of 46 specialized musculoskeletal radiologists from 12 European countries. Statements were scored online by level of agreement (0 to 10) during two iterative rounds. Either "group consensus," "group agreement," or "lack of agreement" was achieved. RESULTS: Eight sections were defined that finally contained 145 statements with comments. Overall, group consensus was reached in 95.9%, and group agreement in 4.1%. This communication contains the first part consisting of the imaging algorithm for suspected soft tissue tumors, methods for local imaging, and the role of tumor centers. CONCLUSION: Ultrasound represents the initial triage imaging modality for accessible and small tumors. MRI is the modality of choice for the characterization and local staging of most soft tissue tumors. CT is indicated in special situations. In suspicious or likely malignant tumors, a specialist tumor center should be contacted for referral or teleradiologic second opinion. This should be done before performing a biopsy, without exception. CLINICAL RELEVANCE: The updated ESSR soft tissue tumor imaging guidelines aim to provide best practice expert consensus for standardized imaging, to support radiologists in their decision-making, and to improve examination comparability both in individual patients and in future studies on individualized strategies. KEY POINTS: • Ultrasound remains the best initial triage imaging modality for accessible and small suspected soft tissue tumors. • MRI is the modality of choice for the characterization and local staging of soft tissue tumors in most cases; CT is indicated in special situations. Suspicious or likely malignant tumors should undergo biopsy. • In patients with large, indeterminate or suspicious tumors, a tumor reference center should be contacted for referral or teleradiologic second opinion; this must be done before a biopsy.

Imaging modalities in the diagnosis and monitoring of Achilles tendon ruptures: A systematic review.

OBJECTIVE: To determine the role of imaging in the diagnosis and monitoring of the Achilles tendon rupture (ATR). STUDY DESIGN: Systematic review. DATA SOURCES: PubMed and EMBASE in November 2016. ELIGIBILITY CRITERIA: Clinical studies providing information on the methods and role of imaging in the diagnosis and monitoring of the ATR were included. RESULTS: Fifty-six studies were included, most concerning the use of ultrasound (n=37) or MRI (n=18). Seven studies provided data on the diagnostic accuracy of imaging. Most ultrasound studies used a 7.5MHz probe (19/32 studies) and scanned the patient bilaterally in prone position, with recent studies tending to use higher frequency probes (r=0.42). Sensitivity [for detecting a rupture] ranged from 79.6 to 100%; the spread in specificity was large but two studies showed perfect (100%) data. Negative and positive likelihood ratios ranged from 0 to 0.23 and 1.0 to 10 respectively. MRI examination was generally performed with 1.5Tesla (T) MRI (6/12 studies) with a strong trend for higher T strength in more recent studies (r=0.71). One study reported a sensitivity of 90.9% and one a specificity of 100%. Although imaging can visualize structure and healing, these results were generally not related to the clinical picture. Overall, ultrasound was recommended over MRI for diagnosis and monitoring. Results of other imaging modalities remain inconclusive. CONCLUSION: The adjunct role of imaging, especially of ultrasound and MRI, in the diagnosis and monitoring of ATRs was established. It is therefore recommended to rely primarily on the clinical examination and evaluation and to use imaging for ruling out other injuries and providing additional clinical information. More high-quality research is warranted into the diagnostic accuracy of imaging as well as less conventional imaging modalities' diagnostic and monitoring capabilities.

The Anterolateral Ligament of the Knee: What the Radiologist Needs to Know.

The anterolateral ligament (ALL) was recently identified as a distinct component of the anterolateral capsule of the human knee joint with consistent origin and insertion sites. Biomechanical studies revealed that the current association between the pivot shift and an injured anterior cruciate ligament (ACL) should be loosened and that the rotational component of the pivot shift is significantly affected by the ALL. This may change the clinical approach toward ACL-injured patients presenting with anterolateral rotatory instability (ALRI), the most common instability pattern after ACL rupture. Radiologists should be aware of the importance of the ALL to ACL injuries. They should not overlook pathology of the anterolateral knee structures, including the ALL, when reviewing MR images of the ACL-deficient knee. In this article, the current knowledge regarding the anatomy, biomechanical function, and imaging appearance of the ALL of the knee is discussed with emphasis on the clinical implications of these findings.

Imaging of the Postoperative Anterior Cruciate Ligament: Emphasis on New Surgical and Imaging Methods.

The aim of anterior cruciate ligament (ACL) reconstruction is to restore normal function of the knee, but unfortunately abnormal kinematics and a predisposition to knee osteoarthritis occur in a significant percentage of patients. So there is an ongoing need to improve treatment options and long-term outcome of patients with a ruptured ACL. With the recent advancements in the field of ACL tissue engineering, the focus of treatment for ACL injuries is changing from resection and reconstruction toward repair and regeneration. Several new ACL repair methods were recently introduced as an alternative to traditional ACL reconstructive procedures. Radiologists must become familiar with these new surgical methods to interpret their appearance correctly on postoperative imaging studies. This article provides an overview of the latest advancements in ACL surgical methods and discusses the role of imaging to assess the postoperative ACL including both standard and advanced imaging methods.

Anterolateral ligament abnormalities in patients with acute anterior cruciate ligament rupture are associated with lateral meniscal and osseous injuries.

OBJECTIVE: To determine the frequency of anterolateral ligament (ALL) injury in patients with acute anterior cruciate ligament (ACL) rupture and to analyse its associated injury patterns. METHODS: Ninety patients with acute ACL rupture for which MRI was obtained within 8 weeks after the initial trauma were retrospectively identified. Two radiologists assessed the status of the ALL on MRI by consensus. The presence or absence of an ALL abnormality was compared with the existence of medial and lateral meniscal tears diagnosed during arthroscopy. Associated collateral ligament and osseous injuries were documented with MRI. RESULTS: Forty-one of 90 knees (46 %) demonstrated ALL abnormalities on MRI. Of 49 knees with intact ALL, 15 (31 %) had a torn lateral meniscus as compared to 25 torn lateral menisci in 41 knees (61 %) with abnormal ALL (p = 0.008). Collateral ligament (p ≤ 0.05) and osseous injuries (p = 0.0037) were more frequent and severe in ALL-injured as compared with ALL-intact knees. CONCLUSION: ALL injuries are fairly common in patients with acute ACL rupture and are statistically significantly associated with lateral meniscal, collateral ligament and osseous injuries. KEY POINTS: • ALL injuries are fairly common in patients with acute ACL rupture. • ALL injuries are highly associated with lateral meniscal and osseous injuries. • MRI assessment of ACL-injured knees should include evaluation of the ALL.

Morphological MR imaging of the articular cartilage of the knee at 3 T-comparison of standard and novel 3D sequences.

OBJECTIVES: This study sought to compare various 3D cartilage sequences and to evaluate the usefulness of ultrashort TE (UTE) imaging, a new technique to isolate signal from the osteochondral junction. METHODS: Twenty knees were examined at 3 T with 3D spoiled GRE (FLASH), double-echo steady-state (DESS), balanced SSFP, 3D turbo spin-echo (TSE), and a prototype UTE sequence. Two radiologists independently evaluated all images. Consensus readings of all sequences were the reference standard. Statistical analysis included Friedman and pairwise Wilcoxon tests. Retrospective analysis of UTE morphology of osteochondral tissue in normal and abnormal cartilage seen at conventional MR was also performed. RESULTS: Three-dimensional TSE was superior to other sequences for detecting cartilage lesions. FLASH and DESS performed best in the subjective quality analysis. On UTE images, normal cartilage exhibited a high-intensity linear signal near the osteochondral junction. Retrospective analysis revealed abnormal UTE morphology of the osteochondral junction in 50 % of cartilage lesions diagnosed at conventional MR. CONCLUSIONS: Cartilage imaging of the knee at 3 T can be reliably performed using 3D TSE, showing high accuracy when compared to standard sequences. Although UTE depicts signal from the deep cartilage layer, further studies are needed to establish its role for assessment of cartilage. MAIN MESSAGES: • MRI is the best available imaging method for assessment of knee cartilage. • Cartilage imaging can be reliably performed using 3D TSE. • UTE cannot be used as a single sequence to assess cartilage.

Comparison of 1.5- and 3-T MR imaging for evaluating the articular cartilage of the knee.

PURPOSE: The aim of this prospective study was to compare routine MRI scans of the knee at 1.5 and 3 T obtained in the same individuals in terms of their performance in the diagnosis of cartilage lesions. METHODS: One hundred patients underwent MRI of the knee at 1.5 and 3 T and subsequent knee arthroscopy. All MR examinations consisted of multiplanar 2D turbo spin-echo sequences. Three radiologists independently graded all articular surfaces of the knee joint seen at MRI. With arthroscopy as the reference standard, the sensitivity, specificity, and accuracy of 1.5- and 3-T MRI for detecting cartilage lesions and the proportion of correctly graded cartilage lesions within the knee joint were determined and compared using resampling statistics. RESULTS: For all readers and surfaces combined, the respective sensitivity, specificity, and accuracy for detecting all grades of cartilage lesions in the knee joint using MRI were 60, 96, and 87% at 1.5 T and 69, 96, and 90% at 3 T. There was a statistically significant improvement in sensitivity (p < 0.05), but not specificity or accuracy (n.s.) for the detection of cartilage lesions at 3 T. There was also a statistically significant (p < 0.05) improvement in the proportion of correctly graded cartilage lesions at 3 T as compared to 1.5 T. CONCLUSION: A 3-T MR protocol significantly improves diagnostic performance for the purpose of detecting cartilage lesions within the knee joint, when compared with a similar protocol performed at 1.5 T. LEVEL OF EVIDENCE: III.

Prospective comparison of 1.5 and 3.0-T MRI for evaluating the knee menisci and ACL.

BACKGROUND: MRI (magnetic resonance imaging) is widely used to diagnose meniscal pathology and ACL (anterior cruciate ligament) tears. Because of the enhanced signal-to-noise ratio and improved image quality at higher field strength, knee MRI equipment is shifting from 1.5 to 3.0 T. To date, objective evidence of improved diagnostic ability at 3.0 T is lacking. The purpose of this prospective study was to assess the accuracy of 1.5 and 3.0-T MRI of the knee, in the same individuals, for diagnosing meniscal pathology and ACL tears, utilizing arthroscopy as the reference standard. METHODS: Two hundred patients underwent MRI of the knee at 1.5 and 3.0 T. All MRI examinations consisted of multiplanar turbo spin-echo sequences. One hundred patients underwent subsequent knee arthroscopy. Two blinded independent radiologists assessed all MRI studies to identify meniscal pathology and ACL tears. In patients with MRI results indicating the need for surgical treatment, the sensitivity and specificity of the 1.5 and 3.0-T protocols for detecting these lesions were determined, utilizing arthroscopy as the reference standard, and compared with use of the McNemar test. The kappa statistic for inter-reader agreement in the 200 patients was calculated. RESULTS: For medial meniscal tears, the mean sensitivity and specificity for the two readers were 93% and 90%, respectively, at 1.5 T and 96% and 88%, respectively, at 3.0 T. For lateral meniscal tears, the mean sensitivity and specificity were 77% and 99%, respectively, at 1.5 T and 82% and 98%, respectively, at 3.0 T. For ACL tears, the mean sensitivity and specificity were 78% and 100%, respectively, at 1.5 T and 80% and 100%, respectively, at 3.0 T. None of the values for either reader differed significantly between the 1.5 and 3.0-T MRI protocols. Inter-reader agreement was almost perfect to perfect (kappa = 0.82 to 1.00). CONCLUSIONS: Routine use of a 3.0-T MRI protocol did not significantly improve accuracy for evaluating the knee menisci and ACL compared with a similar 1.5-T protocol.

Diagnostic performance of 3D SPACE for comprehensive knee joint assessment at 3 T.

OBJECTIVE: To assess the diagnostic performance of 3D sampling perfection with application-optimised contrasts using variable flip-angle evolution (SPACE) turbo spin-echo (TSE) sequences compared to 2D TSE for comprehensive knee assessment at 3 T. METHODS: From January to July 2011, isotropic 3D SPACE was added to a 2D knee protocol at 3 T. Forty patients underwent subsequent arthroscopy. Three readers independently assessed MR images for meniscus, anterior cruciate ligament (ACL) and cartilage lesions. Readers 1 and 2 evaluated 3D and 2D data at separate sittings; reader 3 interpreted the complete exam including 3D and 2D sequences. Accuracies were calculated using arthroscopy as reference standard. McNemar's test (p < 0.05) was used to compare 3D and 2D techniques. RESULTS: The highest diagnostic yield was obtained by reader 3 (accuracies ≥88 %). For the medial meniscus, readers performed better with the 2D technique than with 3D SPACE (accuracies 85-88 % vs. 78-80 %, respectively) (p > 0.05). For the lateral meniscus and ACL, 3D and 2D techniques had similar performance (accuracies ≥93 %). For cartilage lesions, 3D SPACE had significantly lower specificity (p = 0.0156) than the 2D protocol for one reader. CONCLUSION: The conventional 2D TSE acquisition is more reliable than 3D SPACE for comprehensive assessment of the knee at 3.0 T. MAIN MESSAGES: • 3D SPACE is a valuable component of a knee MR protocol at 3 T. • 3D SPACE cannot be used as a single sequence in the MR evaluation of the knee at 3 T. • Knee MR protocols at 3 T should include both 2D and 3D TSE sequences.

Stable or unstable tear of the anterior cruciate ligament of the knee: an MR diagnosis?

PURPOSE: To determine the usefulness of magnetic resonance (MR) imaging to distinguish stable from unstable tears of the anterior cruciate ligament (ACL) of the knee. MATERIALS AND METHODS: MR images of 97 patients with surgically confirmed ACL tear were retrospectively reviewed. According to arthroscopic and clinical examination, these patients had 36 stable and 61 unstable (9 partial and 52 complete) ACL tears. MR images were interpreted by two blinded reviewers and scored with respect to previously reported primary and secondary MR signs of ACL injury. Based on a comprehensive assessment of all the MR findings, ACLs were categorized as being stable or unstable. MR accuracy was calculated considering only primary MR signs and considering both primary and secondary MR signs of ACL injury, separately. Accuracy of each individual primary and secondary MR sign was calculated. RESULTS: Considering only primary MR signs, sensitivity, specificity, and accuracy of MR were 77, 92, and 82%, respectively. Considering both primary and secondary MR signs, sensitivity, specificity, and accuracy of MR were 59, 81, and 67%, respectively. Of all MR signs, discontinuity and abnormal orientation had highest test accuracy (79 and 87%, respectively). Anterior tibial translation, uncovering of the posterior horn of the lateral meniscus, and hyperbuckled PCL were only seen in unstable ACLs (specificity 100%), but these secondary findings had low sensitivity (23%). Bone contusion around the lateral knee compartment was seen in both unstable and stable ACLs (accuracy 64%). CONCLUSION: Previously reported MR imaging signs do not allow accurate distinction between clinically stable and unstable ACL injuries. Anterior tibial translation, uncovering of the posterior horn of the lateral meniscus, and hyperbuckled PCL, if present, are helpful signs in the diagnosis of an unstable tear. The presence of bone marrow edema around the lateral knee compartment is not predictive of ACL insufficiency.

Experience with a frontal core biopsy device in soft tissue and bone lesions.

OBJECTIVE: To assess the efficacy and cost of a new frontloading biopsy system, Spirotome® (system 1), in musculoskeletal lesions, and to compare the results with those obtained with commonly used biopsy devices. METHODS: System 1 was used in all soft tissue lesions (STL) and osteolytic bone lesions (OBL) of patients who presented at our department for CT-guided biopsy between January 2009 and June 2010. Accuracy and cost were compared to those of Bonopty® (system 2) and Tru-cut (system 3) procedures. RESULTS: The efficacy of system 1 was 85% in STL and 89% in OBL. The procedure was well tolerated and caused no complications. System 3 had an efficacy of 84% in STL and OBL combined. The efficacy of system 2 in OBL was 85%. The cost of single-use system 1 and system 2 was comparable, the cost of system 3 and multiuse system 1 compared to single-use system 1 was 25 and 7%, respectively. CONCLUSIONS: The efficacy of system 1 in biopsy of STL and OBL was better than that of system 3. In OBL, the efficacy of system 1 was better than that of system 2. In STL at hazardous locations and small OBL with a thin cortical shell, system 1 offers the advantage of variable length and controlled loading. In these cases, single-use system 1 was cost-effective when compared to surgical biopsy. The cost per procedure of multiuse system 1 was lower than of system 3.

Partial tear of the anterior cruciate ligament of the knee: injury patterns on MR imaging.

PURPOSE: To describe rupture patterns of partial anterior cruciate ligament (ACL) tears on magnetic resonance (MR) imaging. METHODS: MR images of 51 patients with a surgically confirmed partial ACL tear were retrospectively and independently interpreted by 2 experienced, blinded radiologists. Using previously described MR criteria, ACLs were categorized as follows: complete tear, partial tear, isolated anteromedial or posterolateral bundle tear, mucoid degeneration or normal ACL. MR interpretations were compared with the arthroscopic results as the standard of reference. Inter- and intraobserver agreements were determined using kappa (к) coefficients. RESULTS: On MR imaging, ACL injuries were categorized as complete tears (16-23%), partial tears (20-47%), mucoid degeneration (12-27%) or normal ACLs (18-23%). Isolated ACL bundle tears were diagnosed on MR in 6% of our patients. Accuracy of MR for the diagnosis of partial ACL tears was 25-53%. Interobserver agreement was moderate (к = 0.48-0.56). Intraobserver agreement was good (к = 0.72-0.76). CONCLUSION: MR diagnosis of a partial ACL tear is difficult because various tear patterns may be seen. Many partial tears demonstrate MR features that are indistinguishable from complete ACL tear, mucoid ACL degeneration or normal ACL. An isolated ACL bundle tear is infrequently detected on MR images.

Three tesla magnetic resonance imaging of the anterior cruciate ligament of the knee: can we differentiate complete from partial tears?

PURPOSE: To determine the ability of 3.0T magnetic resonance (MR) imaging to identify partial tears of the anterior cruciate ligament (ACL) and to allow distinction of complete from partial ACL tears. MATERIALS AND METHODS: One hundred seventy-two patients were prospectively studied by 3.0T MR imaging and arthroscopy in our institution. MR images were interpreted in consensus by two experienced reviewers, and the ACL was diagnosed as being normal, partially torn, or completely torn. Diagnostic accuracy of 3.0T MR for the detection of both complete and partial tears of the ACL was calculated using arthroscopy as the standard of reference. RESULTS: There were 132 patients with an intact ACL, 17 had a partial, and 23 had a complete tear of the ACL seen at arthroscopy. Sensitivity, specificity, and accuracy of 3.0T MR for complete ACL tears were 83, 99, and 97%, respectively, and, for partial ACL tears, 77, 97, and 95%, respectively. Five of 40 ACL lesions (13%) could not correctly be identified as complete or partial ACL tears. CONCLUSION: MR imaging at 3.0T represents a highly accurate method for identifying tears of the ACL. However, differentiation between complete and partial ACL tears and identification of partial tears of this ligament remains difficult, even at 3.0T.

Three-Tesla magnetic resonance imaging of the meniscus of the knee: What about equivocal errors?

BACKGROUND: The significance of borderline magnetic resonance (MR) findings that are equivocal for a tear of the knee meniscus remains uncertain. Given their higher signal-to-noise ratio (SNR) and greater spatial resolution, these equivocal meniscal tears could be expected to be less frequent using a 3.0T MR system. PURPOSE: To investigate the prevalence of equivocal meniscal tears using 3.0T MR, and to study their impact on MR accuracy compared with arthroscopy in the detection of meniscal tears. MATERIAL AND METHODS: The medical records of 100 patients who underwent 3.0T MR imaging and subsequent arthroscopy of the knee were retrospectively reviewed. Two observers interpreted MR images in consensus, and menisci were diagnosed as torn (abnormality on two or more images), equivocal for a tear (abnormality on one image), or intact, using arthroscopy as the standard of reference. The prevalence of equivocal meniscal tears was assessed, and MR accuracy was calculated as follows: first, considering both torn menisci and equivocal diagnoses as positive for a tear; and second, considering only torn menisci as positive for a tear. RESULTS: Evidence of meniscal tears on MR images was equivocal in 12 medial (12%) and three lateral (3%) menisci. Of these equivocal MR diagnoses, tears were found at arthroscopy in eight medial and one lateral meniscus. In our study, the specificity and positive predictive value increased for both the medial and lateral meniscus when only menisci with two or more abnormal images were considered to be torn: from 80% and 89% to 91% and 94% for the medial meniscus, and from 91% and 73% to 93% and 78% for the lateral meniscus, respectively. CONCLUSION: Subtle findings that are equivocal for a tear of the knee meniscus still make MR diagnosis difficult, even at 3.0T. We recommend that radiologists should rather be descriptive in reporting subtle or equivocal MR findings, alerting the clinician of possible meniscal tear.

Sports-related acute and chronic avulsion injuries in children and adolescents with special emphasis on tennis.

Acute and chronic sports-related muscle and tendon injuries are not infrequent in youngsters. In particular, the physis is prone to trauma as it constitutes the weakest part of the immature skeleton. The type of sports activity determines the location of the lesion. Most commonly, apophyses of the hip and pelvis are subject to avulsion. The purpose of this paper is to give a short overview of the pathogenesis, location, prevalence and imaging characteristics of acute and chronic avulsion injuries in the immature skeleton, with special emphasis on tennis-related injuries. Tennis-related injuries particularly involve apophyses of the ischial tuberosity, the anterior inferior or superior iliac spine and the iliac crest.

Accuracy of MRI in characterization of soft tissue tumors and tumor-like lesions. A prospective study in 548 patients.

The purpose of our study was to assess prospectively the value of MRI in characterization of soft tissue tumors (STT) and soft tissue tumor-like lesions in a multi-institutional setting by a group of experts. The material consisted of 548 untreated and proven STT or tumor-like lesions originating from a multi-institutional database of STT in which 930 consecutive patients with STT examined by MRI were registered between 1 January 2001 and 28 April 2003. Based on MRI findings, a suitably ordered differential diagnosis was made in consensus by two radiologists (J.L.M.A.G and A.M.D.S). MRI diagnoses were compared with histology results (455 cases, 83%) and/or 6-month follow-up (93 cases, 17%) as reference standards. The correlation between the MRI and histological diagnosis and between the radiological and histological phenotype were statistically determined. One hundred twenty-three patients presented with a malignant STT; 425 patients presented with a benign one. Concerning differentiation between malignant and benign lesions (dignity), a sensitivity of 93%, specificity of 82%, negative predictive value (NPV) of 98% and positive predictive value (PPV) of 60% with accuracy of 85% were obtained. Concerning phenotype characterization, if only the first MRI diagnosis was taken into account, a sensitivity of 67%, specificity of 98%, NPV of 98%, PPV of 70% and accuracy of 96% were obtained. For benign lesions, sensitivity of 75%, specificity of 98%, NPV of 98%, PPV of 76% and accuracy of 97% were obtained. The phenotype's definition of malignant STT had a sensitivity of 37%, a specificity of 96%, NPV of 96%, PPV of 40% and an accuracy of 92%. A correct diagnosis compared with histological assessment was proposed in 227(50%) of the 455 histologically confirmed cases. Despite non-quantified MR parameter evaluation, the results of our prospective study were better than those reported in previous studies and demonstrated the need for a centralized approach to such rare pathology.