The value of a new diagnostic strategy for adipocytic soft tissue tumors in adults: A retrospective study

INTRODUCTION

The distinction between lipoma and well-differentiated liposarcoma (WDLPS), or "atypical lipomatous tumor" (ALT), is crucial as it impacts patient management. A group of European experts led by Benjamin Moulin recently issued a consensus report to define the role of radiology in managing these lesions. It describes an algorithm defining the criteria prompting a diagnostic biopsy of deep lipomatous tumors of the limbs and chest wall. The primary aim of this study was to evaluate the algorithm's diagnostic performance.

MATERIALS AND METHODS

Between 2012 and 2019, all biopsies of deep fatty tumors of the limbs or chest wall with a pre-biopsy MRI assessment were recorded at our institution. The MRI scans were reviewed by two radiologists. Each lesion was classified according to biopsy status by applying the algorithm of the European panel. The algorithm's diagnostic performance was assessed by calculating the sensitivity, specificity, positive predictive value and negative predictive value. Inter-rater agreement was also assessed.

RESULTS

Of the 156 tumors in our study, 148 (94.9%) required a biopsy, and the algorithm's sensitivity for detecting ALT/WDLPS was 100% with specificity of 6.3% and a PPV of 20.3%. Inter-rater agreement was almost perfect with a kappa value of 0.882.

CONCLUSION

The European algorithm demonstrates perfect sensitivity, an important criterion for a screening examination such as MRI in this setting. The algorithm's low specificity, however, emphasizes the need for further studies to redefine the optimum size cut-off value, especially for lesions without atypical criteria or an anatomical location at risk of post-surgical recurrence.

Anatomical study of the medial calcaneal nerve using high-resolution ultrasound

OBJECTIVES

To determine whether high-resolution ultrasound (US) can identify the course and relations of the medial calcaneal nerve (MCN).

METHODS

This investigation was initially undertaken in eight cadaveric specimens and followed by a high-resolution US study in 20 healthy adult volunteers (40 nerves) by two musculoskeletal radiologists in consensus. The location and course of the MCN as well as its relationship to adjacent anatomical structures were evaluated.

RESULTS

The MCN was consistently identified by US along its entire course. The mean cross-sectional area of the nerve was 1 mm2 (range 0.5-2). The level at which the MCN branched from the tibial nerve was variable, located a mean of 7 mm (range - 7-60) proximal to the tip of the medial malleolus. At the level of the medial retromalleolar fossa, the MCN was located inside the proximal tarsal tunnel a mean of 8 mm (range 0-16) posterior to the medial malleolus. More distally, the nerve was depicted in the subcutaneous tissue at the surface of the abductor hallucis fascia with a mean direct distance to the fascia of 1.5 mm (range 0.4-2.8).

CONCLUSIONS

High-resolution US can identify the MCN at the level of the medial retromalleolar fossa, as well as more distally in the subcutaneous tissue at the surface of the abductor hallucis fascia. In the setting of heel pain, precise sonographic mapping of the MCN course may enable the radiologist to make diagnosis of nerve compression or neuroma, and perform selective US-guided treatments.

CLINICAL RELEVANCE STATEMENT

In the setting of heel pain, sonography is an attractive tool for diagnosing compression neuropathy or neuroma of the medial calcaneal nerve, and enables the radiologist to perform selective image-guided treatments such as diagnostic blocks and injections.

KEY POINTS

• The MCN is a small cutaneous nerve which rises from the tibial nerve in the medial retromalleolar fossa to the medial side of the heel. • The MCN can be depicted by high-resolution ultrasound along its entire course. • In the setting of heel pain, precise sonographic mapping of the MCN course may enable the radiologist to make diagnosis of neuroma or nerve entrapment, and perform selective ultrasound-guided treatments such as steroid injection or tarsal tunnel release.

Deep learning to detect anterior cruciate ligament tear on knee MRI: multi-continental external validation

OBJECTIVES

To develop a deep-learning algorithm for anterior cruciate ligament (ACL) tear detection and to compare its accuracy using two external datasets.

METHODS

A database of 19,765 knee MRI scans (17,738 patients) issued from different manufacturers and magnetic fields was used to build a deep learning-based ACL tear detector. Fifteen percent showed partial or complete ACL rupture. Coronal and sagittal fat-suppressed proton density or T2-weighted sequences were used. A Natural Language Processing algorithm was used to automatically label reports associated with each MRI exam. We compared the accuracy of our model on two publicly available external datasets: MRNet, Bien et al, USA (PLoS Med 15:e1002699, 2018); and KneeMRI, Stajduhar et al, Croatia (Comput Methods Prog Biomed 140:151-164, 2017). Receptor operating characteristics (ROC) curves, area under the curve (AUC), sensitivity, specificity, and accuracy were used to evaluate our model.

RESULTS

Our neural networks achieved an AUC value of 0.939 for detection of ACL tears, with a sensitivity of 87% (0.875) and a specificity of 91% (0.908). After retraining our model on Bien dataset and Stajduhar dataset, our algorithm achieved AUC of 0.962 (95% CI 0.930-0.988) and 0.922 (95% CI 0.875, 0.962) respectively. Sensitivity, specificity, and accuracy were respectively 85% (95% CI 75-94%, 0.852), 89% (95% CI 82-97%, 0.894), 0.875 (95% CI 0.817-0.933) for Bien dataset, and 68% (95% CI 54-81%, 0.681), 93% (95% CI 89-97%, 0.934), and 0.870 (95% CI 0.821-0.913) for Stajduhar dataset.

CONCLUSION

Our algorithm showed high performance in the detection of ACL tears with AUC on two external datasets, demonstrating its generalizability on different manufacturers and populations. This study shows the performance of an algorithm for detecting anterior cruciate ligament tears with an external validation on populations from countries and continents different from the study population.

KEY POINTS

• An algorithm for detecting anterior cruciate ligament ruptures was built from a large dataset of nearly 20,000 MRI with AUC values of 0.939, sensitivity of 87%, and specificity of 91%. • This algorithm was tested on two external populations from different other countries: a dataset from an American population and a dataset from a Croatian population. Performance remains high on these two external validation populations (AUC of 0.962 and 0.922 respectively).

Anatomical basis for ultrasound-guided infiltration of the saphenous nerve in the subsartorial canal

The present work is aimed studying the visibility and position of the vasto-adductor membrane with ultrasonography and demonstrating that injection performed under this membrane allows to infiltrate the saphenous nerve. It was analyzed with ultrasonography in four cadaveric subjects and in 13 volunteers. This membrane was clearly visible and methylene blue was located underneath it after injection in all cadaveric subjects. This study demonstrates that it can be used as a reliable anatomic landmark when performing an injection for both regional anesthesia and in the treatment of saphenous nerve tunnel syndrome.

Sacroiliac joint in sarcoidosis on computed tomography: a monocentric retrospective study (SISTER)

Sacroiliitis and spondyloarthritis (SpA) have been associated to sarcoidosis. Sarcoidosis bone involvement of the sacral or iliac bones has been reported to mimic SpA. We aimed to evaluate the prevalence of structural sacroiliitis and structural changes of the sacroiliac joints (SIJ) in patients with sarcoidosis by abdominal-pelvic computed tomography (AP-CT). In this monocentric retrospective study, three blinded readers evaluated AP-CT that had already been performed on patients with sarcoidosis and classified them as normal, degenerative, or inflammatory. A consensus was reached for the divergent cases. Erosion, ankylosis, and sclerosis, classically associated with sacroiliitis, were noted. SpA was defined according to the ASAS 2009 classification criteria. We identified 217 patients with proven sarcoidosis who underwent AP-CT. Only three patients had sacroiliitis by CT and four had SpA, representing 1.38% and 1.85% of the patients, respectively. Degenerative SIJs represented 28.1% of patients and were significantly associated with age, at least one pregnancy, rural lifestyle, ankylosis, diffuse idiopathic skeletal hyperostosis, sclerosis, and the presence of osteophytes. Four patients had axial bone sarcoidosis. Sacroiliitis, SpA, and degenerative changes of the SIJ have been highlighted by AP-CT in patients with sarcoidosis. Osteoarthritis of the SIJ in sarcoidosis was associated with age, pregnancy, and rural lifestyle. Further studies are needed to assess the link between SpA and sarcoidosis.

Spondyloarthritis and sarcoidosis: Related or fake friends? A systematic literature review

BACKGROUND

Sarcoidosis and spondyloarthritis (SpA) have been regularly associated. Bone iliac granulomas have also been described. We propose herein a systematic review of rheumatologic axial manifestations of sarcoidosis.

METHODS

PubMed and the Cochrane Library were used to conduct this systematic literature review. Case reports and cross-sectional studies were reviewed according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

A total of 41 articles were eligible. Three cross-sectional studies on the association between SpA and sarcoidosis showed a prevalence of sacroiliitis and SpA ranging from 12.9 to 44.8% and 12.9 to 48.3% in inflammatory back pain (IBP) subgroups, respectively. However, the IBP definitions and sacroiliac joint (SIJ) imaging modalities (X-rays or magnetic resonance imaging) were heterogeneous, and X-ray was mainly used for sacroiliitis diagnosis (in 78% of cases). Thirty-one case-report articles of the sarcoidosis-sacroiliitis association were identified, representing 35 patients. ASAS criteria for SpA were met in half of cases (16/32) and 46% (12/26) had HLA B27 positivity. Sarcoidosis occurred after sacroiliac symptoms in 47% of cases. In the seven case-report articles with granulomatous sacroiliac bone involvement, unilateral involvement seemed higher than in the sarcoidosis-sacroiliitis group.

CONCLUSION

Literature analysis found a good evidence of the association between SpA and sarcoidosis, and special attention should be given to patients reporting IBP. Unilateral sacroiliitis may raise suspicion of granulomatous bone involvement, distinct from sacroiliitis. Imaging modalities used to study the SIJ in patients with sarcoidosis have been heterogeneous and further investigation is needed.

Painful Traumatic Neuromas in Subcutaneous Fat: Visibility and Morphologic Features With Ultrasound

OBJECTIVES

Subcutaneous neuromas usually result from trauma and may lead to dissatisfaction in patients with a trigger point, loss of sensitivity in the relevant territory of innervation, and spontaneous neuropathic pain. Confirming clinically suspected cases of neuroma may prove difficult. The objective of this study was to evaluate the visibility and morphologic features of traumatic subcutaneous neuromas of the limbs with ultrasound (US).

METHODS

Between January 2012 and August 2016, 38 consecutive patients clinically suspected of having subcutaneous neuromas were investigated with US. The diagnosis was confirmed on the basis of a focal morphologic abnormality of the nerve associated with trigger pain. Each neuroma was classified into 1 of 3 subtypes based on its injury pattern. The subtypes were terminal neuroma, spindle neuroma, and scar encasement, either isolated or associated with these subtypes.

RESULTS

Forty-four lesions were found in the 38 patients, including 29 spindle neuromas (65.9%), 14 terminal neuromas (31.8%) and 1 scar encasement with no nerve caliber abnormality (2.3%). Fifteen neuromas (35% of all neuromas) were associated with scar encasement. In 13 cases that required surgery, the diagnosis of neuroma or scar encasement could be surgically proven and confirmed the validity of the US findings.

CONCLUSIONS

Ultrasound can be used to show and classify subcutaneous nerves of the upper and lower limbs with high accuracy. The US trigger sign provides an indication of neuroma involvement in pain. This modality can play a substantial role both in the preoperative planning of neuroma surgery and in therapeutic US-guided procedures.

Back pain following instillations of BCG for superficial bladder cancer is not a reactive complication: review of 30 Mycobacterium bovis BCG vertebral osteomyelitis cases

Mycobacterium bovis Bacillus Calmette-Guérin (BCG) instillations are used in bladder cancer treatment. Adverse effects can occur. Osteoarticular complications are mainly reactive arthritis, but true infections have been described, such as vertebral osteomyelitis. We made a review of M. bovis BCG vertebral osteomyelitis after instillations for bladder cancer using PubMed search. We added three new French cases. Twenty-seven cases of BCG vertebral osteomyelitis had been reported on PubMed. Of the 30 cases, all were male, averaging 73.4 ± 8.7 years old. Median time between diagnosis and first and last instillation was 22.5 and 14 months respectively. Half of vertebral osteomyelitis was thoracic and lumbar in the other half. Sensitivo-motor deficit was present at diagnosis in 42% of cases. Other infectious locations were common, mainly infectious abdominal aortic aneurysms (20%). Rifampicin, ethambutol and isoniazid were the usual therapy. Poor outcomes were reported with 50% of one or more spine surgery. M. bovis BCG vertebral osteomyelitis following bladder instillation for bladder cancer is a rare complication. However, the late onset of back pain after instillations differentiates them from reactive arthritis. Concomitant septic location such as infectious abdominal aortic aneurysms must be known.

Ultrasound in Total Hip Replacement: Value of Anterior Acetabular Cup Visibility and Contact With the Iliopsoas Tendon

OBJECTIVES

To assess visibility of the acetabular cup in total hip replacement and to determine the value of direct and indirect signs of iliopsoas impingement syndrome with ultrasound.

METHODS

Ultrasound examinations were performed by a single operator in 17 patients with iliopsoas impingement syndrome and 48 control patients. Cup visibility, contact between the cup and psoas tendon, and the presence of indirect signs of iliopsoas impingement syndrome were investigated in all patients. When the acetabular cup was visible, its size and position in relation to the psoas tendon were recorded.

RESULTS

Anterior cup visibility (P = .03), contact with the psoas tendon (P < .001), psoas tendinopathy (P = .02), and iliopsoas bursitis (P < .001) were significantly associated with iliopsoas impingement syndrome, the latter reported with specificity of 100%. In the sagittal plane at the level of the psoas tendon, a maximum sagittal length of greater than 5 mm and a posteroanterior cup shift of 3 mm or greater yielded respective sensitivities of 82% and 59% and specificities of 81% and 100%.

CONCLUSIONS

When iliopsoas impingement syndrome is clinically suspected, the presence of iliopsoas bursitis or a posteroanterior cup shift of greater than 3 mm under the psoas tendon serve to confirm the diagnosis. In the absence of these conditions, a therapeutic test may be necessary because of the incomplete, albeit high, specificity of other signs.

Ultrasound characterization of ankle involvement in Löfgren syndrome

BACKGROUND

Bilateral ankle arthritis is a classic diagnostic criterion for Löfgren syndrome. The objective of this study was to use ultrasonography to characterize the articular and periarticular involvement of the ankles in patients with Löfgren syndrome.

METHODS

Multicenter descriptive cohort study of patients with Löfgren syndrome who underwent ultrasonography of the ankles. We collected clinical data, imaging study findings, blood test results, and joint fluid properties in patients who underwent joint aspiration.

RESULTS

Findings from ultrasonography of the ankles in 40 patients were analyzed. The most common B-mode abnormality was subcutaneous edema (26/40), followed by tenosynovitis (22/40), with no differences in frequency across compartments. Joint involvement manifested as synovitis in 7 patients and effusion in 10 patients. Synovitis with increased vascularity by power Doppler was found in 3 patients. No statistically significant associations were found linking synovitis or tenosynovitis to clinical features (age and gender), laboratory tests, or imaging study findings.

CONCLUSION

Contrary to the classical view, our results indicate that ankle involvement in Löfgren syndrome is more often abarticular than articular. The inclusion of bilateral ankle arthritis among the diagnostic criteria for Löfgren syndrome deserves reappraisal.

Entrapment and traumatic neuropathies of the elbow and hand: An imaging approach

Ultrasound and magnetic resonance imaging currently offer a detailed analysis of the peripheral nerves. Compressive and traumatic nerve injuries are the two main indications for imaging investigation of nerves with several publications describing the indications, technique and diagnostic capabilities of imaging signs. Investigation of entrapment neuropathies has three main goals, which are to confirm neuronal distress, search for the cause of nerve compression and exclude a differential diagnosis on the entire nerve. For traumatic nerve injuries, imaging, predominantly ultrasound, occasionally provides essential information for management including the type of nerve lesion, its exact site and local extension.

How long should arthroscopic clavicular resection be in acromioclavicular arthropathy? A radiological-clinical study (with computed tomography) of 18 cases at a mean 4 years' follow-up

INTRODUCTION

Endoscopic clavicular resection is a common procedure, but few studies have analyzed predictive factors for outcome.

HYPOTHESES

1) Computed tomography (CT) of clavicular resection is reproductible; 2) Functional outcome correlates with resection length; 3) Other factors also influence outcome.

MATERIAL AND METHODS

Patients operated on between 2005 and 2010 were called back to establish functional scores (Constant, Simple Shoulder Test [SST], satisfaction) and undergo low-dose bilateral comparative computed tomography (CT) centered on the acromioclavicular joints. The assessment criteria were resection edge parallelism and resection length, measured using OsiriX software. Radiological and clinical data were correlated.

RESULTS

18 out of 21 patients (85%: 3 female, 15 male) were assessed. Mean age at surgery was 49 years (range, 40-62 yrs); mean follow-up was 4.2 years (1.6-7.2 yrs). Mean Constant score rose from 57.7 (25-85) to 70.2 (30-96); mean postoperative SST was 9.3 (3-12). 11 patients had very good and 4 poor results. CT resection length was reproducible, with intraclass, intra- and interobserver correlation coefficients >95%. There was no significant correlation between articular resection length on CT and functional scores (P=0.2). Functional scores were negatively influenced by an occupational pathologic context (P<0.01) and by associated tendinopathy.

DISCUSSION AND CONCLUSION

Low-dose CT enabled reproducible analysis of clavicular resection. The hypothesized correlation between resection length and functional result was not confirmed. Work accidents and occupational disease emerged as risk factors.

LEVEL OF EVIDENCE

Single-center retrospective analytic cohort study. Level 4, guideline grade C.

Dynamic cervical myelopathy in young adults

PURPOSE

Non-traumatic cervical chronic joint instability in young adults is a rare and underexplored entity. We assessed the diagnostic relevance of dynamic MRI, and the clinical and radiological outcome after anterior cervical interbody fusion (ACIF) in these cases.

METHODS

Six young patients (mean age 34 years) with cervical myelopathy without compression on static imaging had a dynamic MRI. Joint instability was defined by a reduction of the canal diameter on dynamic sequences. Clinical and radiological outcomes were assessed after surgery by examination, cervical X-rays, static and dynamic MRI.

RESULTS

All the patients had joint instability. Four patients underwent surgery. Clinical status improved 1 year after surgery. All patients had a satisfactory fusion at 6-month follow-up and no residual compression at 1 year.

CONCLUSION

Dynamic MRI can help detect a joint instability in young patients with cervical myelopathy without compression. ACIF seems to be efficient in these cases.

How can we optimize anterior iliac crest bone harvesting? An anatomical and radiological study

PURPOSE

Anterior iliac crest bone is a widely used donor site for bone harvesting. It provides an autologous bone graft consisting of cancellous bone that can be packed or cortical bone with greater structural support. Uses include spinal fusion and fracture non-union surgery. Although its use is common, dedicated anatomical and radiological studies analysing graft dimensions and optimal harvesting site in relation to local anatomical landmarks [anterior superior iliac spine (ASIS), anterior iliac tubercle (AIT) and lateral femoral cutaneous nerve (LFCN)] have not been described.

METHODS

Twenty-eight female hemipelvises were dissected for this study. The LFCN, ASIS and AIT were identified. Calliper measurements and CT scan analysis were undertaken to determine the optimum positions in obtaining a 5-mm-thickness tricortical graft whilst remaining safe for the LFCN.

RESULTS

According to our measurements, the optimal location for harvesting a 5-mm-thick tricortical graft with 35-mm height and 47-mm width is situated anterior to a line passing at the level of the thickest point of the AIT. This thickest point was situated at a mean 67 mm from the centre of the EIAS in our study.

CONCLUSION

This anatomical and radiographic study determined the anatomical iliac crest landmarks to avoid neurological injury when taking an optimal 5-mm-width tricortical bone graft.

Sonography of orthopedic hardware impingement of the extremities

The purpose of this pictorial essay is to describe the sonographic appearance of orthopedic hardware impingement of the extremities. Sonography is not limited by metallic artifacts, can show the orthopedic hardware, and can be used to assess damage of adjacent soft tissues, including tendons, synovial bursas, muscles, nerves, and vessels. Its dynamic capabilities permit assessment of orthopedic hardware impingement present only in certain joint positions, during muscle contractions, and during tendon movements. Local pain elicited with application of pressure from the transducer confirms the diagnosis. Sonographically guided injections of steroid-anesthetic mixtures have both diagnostic and therapeutic effects.

Imaging of snapping phenomena

Snapping phenomena result from the sudden impingement between anatomical and/or heterotopical structures with subsequent abrupt movement and noise. Snaps are variously perceived by patients, from mild discomfort to significant pain requiring surgical management. Identifying the precise cause of snaps may be challenging when no abnormality is encountered on routinely performed static examinations. In this regard, dynamic imaging techniques have been developed over time, with various degrees of success. This review encompasses the main features of each imaging technique and proposes an overview of the main snapping phenomena in the musculoskeletal system.

Subperiosteal hematoma of the iliac bone: imaging features of acute and chronic stages with emphasis on pathophysiology

PURPOSE

The goal of this work is to describe the radiological appearance and clinical presentation of subperiosteal iliac hematoma and present a review of the literature.

MATERIALS AND METHODS

We retrospectively reviewed the radiological and clinical files of 19 patients (age range: 12-75; mean: 47) who presented with acute or chronic subperiosteal iliac hematomas. Imaging findings and relevant clinical information were recorded. A thorough literature search was performed to find additional cases of this rare condition.

RESULTS

Three young patients presented with acute subperiosteal iliac hematoma following a fall. Clinical presentation was characterized by pain and gait disturbance presumed to result from crural nerve compression. Unilateral or bilateral lenticular hematomas deep in the iliacus muscle were demonstrated by CT for all patients while MRI was also available for two of them. In 16 asymptomatic patients, chronic ossified subperiosteal iliac hematomas were incidentally detected by CT. Progressive ossification of acute hematoma was demonstrated at follow-up in two patients.

CONCLUSIONS

Subperiosteal iliac hematoma is rare but has typical imaging findings that may present acutely in adolescents or chronically in asymptomatic adults.

Sonographic assessment of orthopedic hardware impingement on soft tissues of the limbs

Ultrasonography allows high-resolution imaging with real-time correlation to patients' pain, and it is an indispensable tool for assessing disorders associated with soft tissue impingement by orthopedic hardware. The sonographic examination in these cases begins with static studies, and images are then obtained during active and passive joint mobilization designed to reproduce the conflict with the orthopedic hardware. Ultrasonography is particularly useful for documenting hardware-induced injury to tendons and synovial bursae, but also those of muscles and vascular structures. The frequency of hardware-soft tissue conflict varies with the site and type of surgical procedure, but in all cases ultrasonography plays an essential role in identifying this type of conflict and assessing the soft tissue lesions it causes.

Can we improve radiological analysis of osseous lesions in chronic anterior shoulder instability?

Osseous lesions of the glenoid cavity and humeral head are predictive of recurrence after Bankart arthroscopic procedures. The objective of this study was to analyze, for each glenoid and humeral defect plain x-ray criteria of the Instability Severity Index Score (ISIS), two aspects: inter- and intraobserver reliability of their qualitative and quantitative assessment and correlations between positive criteria and their quantitative measurement. Thirty-one medical files were retained for evaluation of the glenoid and 26 for humeral notch assessment. The yes or no response for the ISIS criterion was completed by its quantitative measurement using the Griffiths and Sugaya CT methods for the glenoid and the P/R index calculation on plain x-rays with internal rotation for the Hill-Sachs lesion. Three observers provided two consecutive readings for each criterion. The analysis of the glenoid radiological criterion of the ISIS seems sufficiently reproducible for daily practice. When the evaluation is positive, bone loss is greater than 15%, without a maximum value established. In this study, the analysis of the ISIS humeral notch criterion was not reproducible. It can be improved using the P/R index and should be completed by CT imaging.

Snapping biceps femoris tendon: a dynamic real-time sonographic evaluation

Snapping of the distal arms of the biceps femoris tendon may explain pain and discomfort at the lateral aspect of the knee. We report two cases in which dynamic sonography was able to confirm the diagnosis and document which of the main arms was involved in the process.