Fluid-fluid levels in bone neoplasms: variation of T1-weighted signal intensity of the superior to inferior layers—diagnostic significance on magnetic resonance imaging

Abstract

The diagnostic relevance of the relative T1-weighted (T1W) and T2-weighted (T2W)/short tau inversion recovery (STIR) MRI signal intensity characteristics of the superior to inferior fluid layers within fluid-fluid levels (FFLs) found in bone tumours was investigated. A retrospective analysis was performed of MRI studies of 2,568 patients presenting with a suspected bone tumour over an 8-year period. Final diagnosis was made by biopsy/surgical resection or characteristic imaging/clinical findings. Subjects were divided by the absence/presence of FFLs and benign/malignant histology. Cases with FFLs were sub-categorised by the relative signal intensity of the superior/inferior layer as high/low or low/high on T1W and T2W/STIR sequences. Out of the total of 2,568 cases, 214 (8.3%, CI 7.3-9.5%) had FFLs and 2,354 (91.7%, CI 90.5-92.7%) had no FFLs. All 214 cases with FFLs had T2W/STIR sequences available, all demonstrating high/low signal intensity characteristics; 135/214 (63.1%, CI 56.2-69.6%) were benign and 79/214 (36.9%, CI 30.4-43.8%) were malignant. Out of the 214 patients, 151 had T1W sequences performed; 52 showed high/low signal intensity, of which 30 (57.7%, CI 34.2-71.3%) were benign and 22 (42.3%, CI 28.7-56.8%) were malignant (P = 0.06 compared with no FFL group); 50 showed low/high signal intensity, of which 40 (80%, CI 66.3-90.0%) were benign and ten (20%, CI 10.0-33.7%) were malignant (P = 0.0000, compared with the no FFL group). The low/high and high/low groups had a significantly greater proportion of benign and malignant lesions, respectively (P = 0.015). In conclusion, all FFLs showed high/low signal intensity characteristics on T2W/STIR sequences. Low/high signal on T1W was significantly associated with benign disease. Malignancy may occur slightly more frequently with high/low signal on T1W.

Primary giant cell tumor of soft tissue: fluid-fluid levels at MRI (2010:3b)

“…In our case there were also fluid-fluid levels (FFLs) in more than half of the mass, an unspecific finding that may occur in a wide range of bone and soft tissue tumors, benign and malignant and non-neoplastic disease [13][14][15][16]. Usually they are related to prior hemorrhage or tumor necrosis [13,14].…”

CT and MRI of Pediatric Skull Lesions with Fluid-Fluid Levels

“…There is no dedicated study on the most common etiology of osseous lesions with FFLs in pediatric patients, to our knowledge. In addition, large studies that may have included some pediatric patients had not published their detailed results based on age groups, [5][6][7] and the current literature is mainly limited to published case reports. [9][10][11][12][13][14] There are only 2 case reports describing the presence of fluid-fluid level in LCH.…”

“…However, 2 large studies primarily in adult patients have demonstrated that ABCs are the most common etiology of osseous lesions with FFLs throughout the body. 5,6 Despite these data, the presence of FFLs remains a nonspecific finding and can be seen in a wide range of benign and malignant bone lesions, including fibrous dysplasia, telangiectatic osteosarcoma, osteoblastoma, simple bone cyst, lymphatic malformations, Ewing sarcoma, brown tumor, giant cell tumor, and chondroblastoma. [5][6][7][8][9] In this study, head CT and MR imaging of pediatric patients having skull lesions with FFLs were retrospectively reviewed with the aim of characterizing these lesions.…”

Craniospinal Polyostotic Fibrous Dysplasia, Aneurysmal Bone Cysts, and Chiari Type 1 Malformation Coexistence in a Patient with McCune-Albright Syndrome

“…CT and MRI reveal FD as diffuse hyperostosis, bony expansion with ground glass appearance, intraosseous cysts, and contrast enhancement [9,13], whereas ABCs are expansile and destructive, containing blood-fluid level lesions [13]. However, the presence of free-fluid levels remains a nonspecific finding and can be seen in a wide range of benign and malignant bone lesions, including cephalohematoma, histiocytosis, telangiectatic osteosarcoma, osteoblastoma, simple bone cyst, lymphatic malformations, Ewing sarcoma, brown tumor, giant cell tumor, leukemia, myelodysplasia syndromes, metastases, non-Hodgkin lymphoma, multiple myeloma, mastocytosis, Paget disease, and chondroblastoma [14,15,16,17]. …”