Study of neurinomas with ultrasound contrast media: review of a case series to identify characteristic imaging patterns

The Clinical Value of Extracorporeal Shock Wave Therapy Evaluated by Contrast-Enhanced Ultrasound for Noninfectious Nonunion

Objectives: The aim of this study was to investigate the clinical value of Contrast-enhanced ultrasound (CEUS) in evaluating Extracorporeal shock wave therapy (ESWT) for noninfectious nonunion. Methods: Thirty-eight patients with long bone nonunion fractures whose were treated in our hospital from October 2016 to October 2019 were included (20 males and 18 females). The patients received ESWT once a week for 12 consecutive weeks. CEUS was performed before and after the first ESWT session. According to the ratio of the perfusion area to the callus area, neovascular blood flow observed in CEUS was divided into 4 grades: grade 0 = 0%, grade 1 = 0–30%, grade 2 = 30–70% and grade 3 = 70–100%. The peak values of microbubbles perfusion in the callus area were recorded before and after ESWT. Each patient was followed up for 12 months to record the healing time. Nonunion over 12 months was considered a nonhealing fracture. To compare the ultrasonic data before and after ESWT, paired T test was used and the correlation between the ultrasonic data and the nonunion healing time, the pearson analysis was used. Results: Of the 38 patients, 35 patients achieved nonunion healing. The healing time ranged from 5 months to 12 months. Among the 38 patients, 24 patients had a microvascular health score of 0 points and 14 patients had a score of 1 point before treatment. After therapy, the neovascular health score was 0, 1, 2 and 3 in 5, 10, 15 and 8 patients, respectively. There was a statistically significant difference before and after treatment (P < 0.05). The peak value of microbubbles perfusion in the fracture site after ESWT was significantly higher than that before ESWT (P < 0.05). The greater of difference, the shorter of healing time. Conclusion: Under the supervision of CEUS, the changes in microvascular perfusion of noninfectious nonunion patients before and after ESWT effectively reflected the therapeutic effect. CEUS could predict the ESWT on bone nonunion at an early stage. Level of evidence: Level III.

Technical and clinical feasibility of contrast-enhanced ultrasound evaluation of long bone non-infected nonunion healing

PURPOSE

To assess the technical feasibility of contrast-enhanced ultrasound (CEUS) in the monitoring of non-infected long bone nonunion healing.

METHODS

Twenty-five patients (16 males; mean age: 40.4 ± 11.7) with long bone nonunion were treated using surgery and mesenchymal stem cells and platelet-rich plasma. They performed CEUS up to 15 days before, 7 days, 4 and 8 weeks after treatment. To categorize the angiogenesis around the fracture site, the microvascular blood flow from CEUS was classified into four categories, depending on the portion of the investigated area that was involved in the neovascularization process: grade 0 = 0%; grade 1 = 0-30%; grade 2 = 30-70%; grade 3 = 70-100%. Nonparametric Friedman and Wilcoxon statistics were used.

RESULTS

Before treatment, neovascularization was graded as 0 in 15/25 patients, as 1 in 10/25. Vascularity significantly increased over time (P < 0.001), namely: 1 (25th-75th percentile = 1-2) at 7 days; 2 (1-2) at 4 weeks; 3 (0-2) at 8 weeks. All patients but one showed early progressive increase in neovascularization well identified with CEUS at the fracture site.

CONCLUSION

CEUS is a feasible method to monitor healing in patients with long bone nonunion.

Perfusion pattern and time of vascularisation with CEUS increase accuracy in differentiating between benign and malignant tumours in 216 musculoskeletal soft tissue masses

INTRODUCTION

Musculoskeletal Soft Tissue Tumours (STT) are frequent heterogeneous lesions. Guidelines consider a mass larger than 5 cm and deep with respect to the deep fascia potentially malignant. Contrast Enhanced Ultrasound (CEUS) can detect both vascularity and tumour neoangiogenesis. We hypothesised that perfusion patterns and vascularisation time could improve the accuracy of CEUS in discriminating malignant tumours from benign lesions.

MATERIALS AND METHODS

216 STT were studied: 40% benign lesions, 60% malignant tumours, 56% in the lower limbs. Seven CEUS perfusion patterns and three types of vascularisation (arterial-venous uptake, absence of uptake) were applied. Accuracy was evaluated by comparing imaging with the histological diagnosis. Univariate and multivariate analysis, Chi-square test and t-test for independent variables were applied; significance was set at p<0.05 level, 95% computed CI.

RESULTS

CEUS pattern 6 (inhomogeneous perfusion), arterial uptake and location in the lower limb were associated with high risk of malignancy. CEUS pattern has PPV 77%, rapidity of vascularisation PPV 69%; location in the limbs is the most sensitive indicator, but NPV 52%, PPV 65%. The combination of CEUS-pattern and vascularisation has 74% PPV, 60% NPV, 70% sensitivity. No correlation with size and location in relation to the deep fascia was found.

CONCLUSION

US with CEUS qualitative analysis could be an accurate technique to identify potentially malignant STT, for which second line imaging and biopsy are indicated in Referral Centers. Intense inhomogeneous enhancement with avascular areas and rapid vascularisation time could be useful in discriminating benign from malignant SST, overall when the lower limbs are involved.

Imaging of the peripheral nervous system

This chapter summarizes progress in the evaluation of peripheral nerve (PN) lesions and disorders by imaging techniques encompassing magnetic resonance imaging (MRI) and nerve ultrasound (US). Due to the radiation exposure and limited sensitivity in soft tissue contrast, computed-tomography (CT) plays no significant role in the diagnostic work-up of PN disorders. MRI and US are complementary techniques for the evaluation of peripheral nerves, each having particular advantages and disadvantages. Nerve injury induces intrinsic MRI signal alterations on T2-weighted sequences in degenerating or demyelinating nerve segments as well as in corresponding muscle groups exhibiting denervation which can be exploited diagnostically. Nerve US is based on changes in the nerve echotexture due to tumor formation or focal enlargement caused by entrapment or inflammation. Both MRI and US provide morphological information on the precise site and extent of nerve injury. While US has the advantage of easy accessibility, providing images with superior spatial resolution at low cost, MRI shows better soft tissue contrast and better image quality for deep-lying nerve structures since imaging is not hindered by bone. Recent advances have remarkably increased spatial resolution of both MRI and US making imaging indispensible for the elucidation of causes of nerve compression, peripheral nerve tumors, and focal inflammatory conditions. Both MRI and US further guide neurosurgical exploration and can simplify treatment. Importantly, imaging can reveal treatable conditions even in the absence of gross electrophysiological alterations, illustrating its increasing role in clinical practice. In experimental settings, novel molecular and cellular MRI contrast agents allow in-vivo assessment of nerve regeneration as well as monitoring of neuroinflammation. Depending on further clinical development, contrast-enhanced MRI has the potential to follow cellular responses over time in vivo and to overcome the current limitations of histological assessment of nerve afflictions. Further advances in contrast-enhanced US has the potential for developing into a tool for the assessment of nerve blood perfusion, paving the way for better assessments of ischemic neuropathies.

Ultrasonography in the diagnosis of peripheral nerve disease

INTRODUCTION

High-resolution ultrasound (US) of the peripheral nerves is now a standard means of assessing neuromuscular disorders in many centers. Currently used in conjunction with electrodiagnostic (EDX) studies, nerve US is especially effective in the diagnosis of entrapment neuropathies.

AREAS COVERED

This article reviews the basic physics of peripheral nerve US, guidelines for its current use and future directions. Advantages of using nerve US alongside EDX studies are outlined along with current limitations of testing. The role of US in the diagnosis of entrapment neuropathy is emphasized, particularly in carpal tunnel syndrome (CTS). US assisted diagnosis of peripheral nerve tumors, hereditary neuropathy and dysimmune neuropathy and traumatic injuries is also described.

EXPERT OPINION

US is a powerful tool in the assessment of peripheral nerve disease. Nerve US is an evolving, young discipline. There is still much to learn, but current evidence supports US imaging of all patients presenting for evaluation of possible mononeuropathy. With improvements in resolution, the introduction of US contrast agents and objective measures of nerve echogenicity, there is promise for further expanding its role in the diagnosis of all peripheral neuropathies.