MRI-Based radiomics nomogram for differentiation of benign and malignant lesions of the parotid gland.

OBJECTIVES: Preoperative differentiation between benign parotid gland tumors (BPGT) and malignant parotid gland tumors (MPGT) is important for treatment decisions. The purpose of this study was to develop and validate an MRI-based radiomics nomogram for the preoperative differentiation of BPGT from MPGT. METHODS: A total of 115 patients (80 in training set and 35 in external validation set) with BPGT (n = 60) or MPGT (n = 55) were enrolled. Radiomics features were extracted from T1-weighted and fat-saturated T2-weighted images. A radiomics signature model and a radiomics score (Rad-score) were constructed and calculated. A clinical-factors model was built based on demographics and MRI findings. A radiomics nomogram model combining the Rad-score and independent clinical factors was constructed using multivariate logistic regression analysis. The diagnostic performance of the three models was evaluated and validated using ROC curves on the training and validation datasets. RESULTS: Seventeen features from MR images were used to build the radiomics signature. The radiomics nomogram incorporating the clinical factors and radiomics signature had an AUC value of 0.952 in the training set and 0.938 in the validation set. Decision curve analysis showed that the nomogram outperformed the clinical-factors model in terms of clinical usefulness. CONCLUSIONS: The above-described radiomics nomogram performed well for differentiating BPGT from MPGT, and may help in the clinical decision-making process. KEY POINTS: • Differential diagnosis between BPGT and MPGT is rather difficult by conventional imaging modalities. • A radiomics nomogram integrated with the radiomics signature, clinical data, and MRI features facilitates differentiation of BPGT from MPGT with improved diagnostic efficacy.

Extraosseous spinal epidural plasmocytoma associated with multiple myeloma: Two case reports.

BACKGROUND: Multiple myeloma is a malignant hematological disease characterized by proliferation of monoclonal plasma cells mainly in the bone marrow. Extraosseous epidural plasmacytoma associated with myeloma arises from lymphoid tissue in the epidural space without focal vertebral involvement, and is rare. CASE SUMMARY: A 52-year-old woman was diagnosed with kappa subtype nonsecretory multiple myeloma and presented with bilateral arm weakness 11 mo after completing multiple courses of chemotherapy. Spinal magnetic resonance imaging (MRI) showed a posterior C7-T3 epidural mass with spinal cord compression. After five courses of chemotherapy, follow-up MRI showed resolution of cord compression. A 54-year-old man presented with paraplegia 15 mo after a diagnosis of IgD kappa subtype multiple myeloma and completing multiple courses of chemotherapy. He underwent Th11 and L1 laminectomies for tumor resection because MRI showed an epidural mass causing cord compression. His-topathologic examination was consistent with IgD multiple myeloma. The patients have currently survived for 33 mo and 19 mo, respectively. CONCLUSION: Isolated extraosseous epidural plasmacytoma associated with multiple myeloma without bony involvement is difficult to diagnose by imaging. Definitive diagnosis requires pathological and immunohistochemical examination.

Computed tomography and magnetic resonance imaging features of cervical chordoma.

Computed tomography (CT) and magnetic resonance imaging (MRI) scans of 11 patients with histologically proven cervical chordoma were retrospectively evaluated. Imaging features assessed included location, morphology, association with adjacent structures, vertebral destruction, status of cortical bone, periosteal reaction, attenuation and calcification by CT, and signal intensity and enhancement pattern by MRI. Of 7 cases with CT, 6 exhibited lytic-sclerotic bone destruction. A total of 5 cases exhibited pressure erosion of outer cortex, 3 of which had spiculated periosteal reaction. Calcification was observed in 3 cases. All cases were heterogeneous and hypodense. MRI T2-weighted images (n=10) revealed heterogeneous hyperintense (n=5), intermediate (n=2) and intermediate-hyperintense signal intensity (n=3). Hypointense septa between lobules (n=5) and stripes (n=3) were observed on T2-weighted images. Post-contrast magnetic resonance images (n=6) demonstrated marked heterogeneous (n=3) and ring-like (n=3) enhancement. CT scanning is valuable in revealing the lytic-sclerotic bone destruction, pressure erosion of outer cortex and calcification. MRI is useful in demonstrating the results of soft tissue mass. The two examinations are necessary for differential diagnosis of patients with suspected cervical chordoma.

Spinal Epidural Cavernous Hemangioma: A Clinical Series of 7 Patients.

OBJECTIVE: To investigate imaging characteristics of spinal epidural cavernous hemangiomas (ECHs) and improve understanding of this rare disease. METHODS: This retrospective study included 7 cases of ECH, confirmed with surgical pathology and imaging. All patients underwent computed tomography and conventional magnetic resonance imaging. One patient underwent diffusion-weighted imaging. RESULTS: ECH originated from vertebrae with coarsened trabeculae in 5 patients. Among these, 1 tumor was mainly in the intervertebral foramen and paravertebral space, 2 extended to the intraspinal and paravertebral spaces and appeared dumbbell-shaped, and 2 were located in the intraspinal space. Purely epidural hemangiomas were present in 2 patients; 1 of these patients had adjacent bony erosion. Epidural hemangiomas were isointense in 6 patients and hyperintense in 1 patient on T1-weighted images; lesions were hyperintense on T2-weighted images in all 7 patients. Peripheral fat was present in 4 ECHs; 2 were of vertebral origin, and 2 were of epidural space origin. In the patient who underwent diffusion-weighted imaging, the lesion showed restricted diffusion. The affected vertebra had coarsened trabeculae, which may be a critical finding for differentiating ECHs of vertebral origin from foraminal nerve sheath tumors. Peripheral fat around hemangiomas of vertebral origin and primary epidural space hemangiomas indicates chronicity. CONCLUSIONS: ECHs are classified either as epidural hemangiomas of vertebral origin or as primary epidural hemangiomas. Awareness of imaging characteristics of ECHs may facilitate diagnosis and treatment of these lesions.

Magnetic Resonance Features and Characteristic Vascular Pattern of Alveolar Soft-Part Sarcoma.

OBJECTIVE: The aim of this study was to investigate the magnetic resonance (MR) features of alveolar soft-part sarcoma (ASPS). METHODS: We studied 12 patients with ASPS confirmed by pathology in this retrospective study. MR features were analyzed, especially for the location, morphology, signals, and related enhanced features of the tumor vessels. RESULTS: Flow voids were shown in the central part of the tumor on T2-weighted imaging (T2WI) in all patients; they were arrayed in a radiating mode gathered toward the center (8 cases), designated by us as vascular center-gathered syndrome (VCGS), or scattered like twigs (4 cases). The flow voids were accompanied by high signals in all patients, including tubular (6 cases) and platy (6 cases) signals. Slightly higher signals were shown in the peripheral part of the tumor in all patients. Flow voids in the peripheral part were shown in all patients, and the majority of the flow voids surrounded the tumor (8 cases). The vessels around the tumor in 9 patients showed high signals, and the majority of the vessels were located at the superior and inferior poles (8 cases). 6 patients underwent enhanced scanning, including moderate (5 cases) and significant enhancement (1 case). CONCLUSION: Low signals of radiating flow voids accompanied by high signals of slow blood flow or blood sinuses in the center part have high significance for the diagnosis of ASPS.