The Role of Ultrasound in the Diagnosis of Soft Tissue Tumors

The beauty of pediatric musculoskeletal ultrasound

Ultrasound is a powerful technique in pediatric imaging and musculoskeletal (MSK) imaging in many specific clinical scenarios. This article will feature some common and less common spot diagnoses in pediatric musculoskeletal ultrasound.Cases were collected by members of the Educational Committee of the ESSR (European Society of musculoSkeletal Radiology) and the Pediatric Subcommittee of the ESSR with expertise in musculoskeletal ultrasound.Fifteen clinical entities are discussed based on the features that allow diagnosis by ultrasound.Clinical history, location, and ultrasound appearance are the keys to spot diagnoses when performing pediatric musculoskeletal ultrasound. · Ultrasound in pediatric musculoskeletal imaging can achieve a diagnosis in specific clinical settings.. · Clinical history, location, and ultrasound appearance are keys to spot diagnoses.. · Knowledge of spot diagnoses in pediatric musculoskeletal ultrasound facilitates daily clinical practice..

Deep learning models of ultrasonography significantly improved the differential diagnosis performance for superficial soft-tissue masses: a retrospective multicenter study

BACKGROUND

Most of superficial soft-tissue masses are benign tumors, and very few are malignant tumors. However, persistent growth, of both benign and malignant tumors, can be painful and even life-threatening. It is necessary to improve the differential diagnosis performance for superficial soft-tissue masses by using deep learning models. This study aimed to propose a new ultrasonic deep learning model (DLM) system for the differential diagnosis of superficial soft-tissue masses.

METHODS

Between January 2015 and December 2022, data for 1615 patients with superficial soft-tissue masses were retrospectively collected. Two experienced radiologists (radiologists 1 and 2 with 8 and 30 years' experience, respectively) analyzed the ultrasound images of each superficial soft-tissue mass and made a diagnosis of malignant mass or one of the five most common benign masses. After referring to the DLM results, they re-evaluated the diagnoses. The diagnostic performance and concerns of the radiologists were analyzed before and after referring to the results of the DLM results.

RESULTS

In the validation cohort, DLM-1 was trained to distinguish between benign and malignant masses, with an AUC of 0.992 (95% CI: 0.980, 1.0) and an ACC of 0.987 (95% CI: 0.968, 1.0). DLM-2 was trained to classify the five most common benign masses (lipomyoma, hemangioma, neurinoma, epidermal cyst, and calcifying epithelioma) with AUCs of 0.986, 0.993, 0.944, 0.973, and 0.903, respectively. In addition, under the condition of the DLM-assisted diagnosis, the radiologists greatly improved their accuracy of differential diagnosis between benign and malignant tumors.

CONCLUSIONS

The proposed DLM system has high clinical application value in the differential diagnosis of superficial soft-tissue masses.

ACR Appropriateness Criteria® Soft Tissue Masses: 2022 Update

Imaging should be performed in patients with a suspected soft tissue mass that cannot be clinically confirmed as benign. Imaging provides essential information necessary for diagnosis, local staging, and biopsy planning. Although the modalities available for imaging of musculoskeletal masses have undergone progressive technological advancements in recent years, their overall purpose in the setting of a soft tissue mass remains unchanged. This document identifies the most common clinical scenarios related to soft tissue masses and the most appropriate imaging for their assessment on the basis of the current literature. It also provides general guidance for those scenarios that are not specifically addressed. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Sarcoma Imaging Surveillance

Soft tissue sarcomas (STS) are a heterogeneous group of solid tumors. There are many histologic subtypes. The prognosis after treatment may be estimated by the analysis of the type of tumor, grade, depth, size at diagnosis, and age of the patient. These type of sarcomas most commonly metastasize to the lungs and may have a relatively high rate of local recurrence, depending on the histologic type and surgical margins. Patients with recurrence have a poorer prognosis. The surveillance of patients with STS is therefore extremely important. This review analyzes the role of MR imaging and US in detecting local recurrence.

The Role of Thoracic Ultrasound for Diagnosis of Diseases of the Chest Wall, the Mediastinum, and the Diaphragm-Narrative Review and Pictorial Essay

The diagnostic capabilities of ultrasound extend far beyond the evaluation of the pleural space and lungs. Sonographic evaluation of the chest wall is a classic extension of the clinical examination of visible, palpable, or dolent findings. Unclear mass lesions of the chest wall can be differentiated accurately and with low risk by additional techniques such as color Doppler imaging, contrast-enhanced ultrasound, and, in particular, ultrasound-guided biopsy. For imaging of mediastinal pathologies, ultrasound has only a complementary function but is valuable for guidance of percutaneous biopsies of malignant masses. In emergency medicine, ultrasound can verify and support correct positioning of endotracheal tubes. Diaphragmatic ultrasound benefits from the real-time nature of sonographic imaging and is becoming increasingly important for the assessment of diaphragmatic function in long-term ventilated patients. The clinical role of thoracic ultrasound is reviewed in a combination of narrative review and pictorial essay.

Magnetic Resonance Imaging or Ultrasound in Localized Intermediate- or High-Risk Soft Tissue Tumors of the Extremities (MUSTT): Final Results of a Prospective Comparative Trial

Objectives: To report final results of the MUSTT trial, which has been designed to independently compare magnetic resonance imaging (MRI) and ultrasound (US) for local recurrences of non-metastatic patients operated for malignant soft tissue tumors (STT). Methods: Magnetic resonance imaging or ultrasound in soft tissue tumors (MUSTT) is a prospective monocentric study recruiting asymptomatic, non-metastatic patients operated on for localized soft tissue sarcomas between 2015 and April. Eligible patients had MRI and physician-performed ultrasound (US) with an independent interpretation of imaging. Outcome measures were compared using ROC analysis and the X² test. An analysis of all patients was performed on a per-follow-up event basis. Results: A total of n = 51 patients who met the inclusion criteria agreed to participate. Among them, n = 8 were lost to follow-up, n = 6 had US and MRI acquired after a time frame > 7 days and were therefore excluded. Complete data available for 37 patients with 232 MRI and 232 US scan were finally considered (men/women: 18/20; age range, 18–84 years). Recurrences within 5 years occurred in 10/37 patients (27%). ROC analysis comparing US and MRI showed an AUC with 95% confidence intervals of 0.909 (0.832 to 0.981) for US and 0.966 (0.939 to 0.989) for MRI with Prob > X² = 0. Conclusions: Each of these tests detected local recurrences with suitable accuracy. MRI did not result clearly superior to US in terms of diagnostic accuracy, but US showed some false positive or negative results.

Herniated superficial lipomas in gluteal and thigh support areas: a special clinical ultrasound presentation

BACKGROUND

Lipomas are the most frequent benign tumor. They have been described as soft, well-defined, slow-growing palpable masses, and classified as deep or superficial.

PURPOSE

To present the clinical and ultrasound findings of herniated superficial subcutaneous lipoma (HSL), located in pressure/support areas, not previously described.

MATERIAL AND METHODS

A seven-year retrospective review was performed. Patients with a preoperative high-resolution ultrasound (HRUS) diagnosis of HSL archived in the computational system and histological study information were selected.

RESULTS

A total of 37 patients (mean age = 46 years) were recruited. The clinical diagnoses were "lipoma" or "suspected lipoma" in just 46% of the cases. This was three times more frequent in women. Tumors were located mainly in the gluteal (38%) and proximal thigh areas (35%). Clinically, all patients showed small, soft, rounded skin nodules. On HRUS, they appear as lipomatous tumors that protruded, compressed, and thinned the covering dermal layer. The subcutaneous portion was bigger than the herniated part, with an iceberg image.

CONCLUSION

HSL in support areas have a special clinical ultrasound presentation, not previously described. It is important to recognize them for a proper diagnosis and treatment, especially because they clinically may present as small superficial lesions; however, they are associated with a larger subcutaneous portion (iceberg image). It is probable that an estrogen influence on the adipose tissue can be suspected because of the female predominance.

Primary Tumors of the Sacrum: Imaging Findings

The diagnosis of sacral neoplasms is often delayed because they tend to remain clinically silent for a long time. Imaging is useful at all stages of managing sacral bone tumors: from the detection of the neoplasm to the long-term follow-up. Radiographs are recommended as the modality of choice to begin the imaging workup of a patient with known or suspected sacral pathology. More sensitive examinations such as computerized tomography (CT), magnetic resonance (MRI), or scintigraphy are often necessary. The morphological features of the lesions on CT and MRI help to orientate the diagnosis. Although some imaging characteristics are helpful to limit the differential diagnosis, an imaging-guided biopsy is often ultimately required to establish a specific diagnosis. Imaging is of paramount importance even in the long-term follow-up in order to assess any residual tumor when surgical resection is incomplete, to assess the efficacy of adjuvant chemotherapy and radiotherapy, and to detect recurrence.