Atypical Hemangioma Mimicking Metastasis on 18F-Sodium Fluoride Positron Emission Tomography-Computed Tomography and Magnetic Resonance Imaging: Gallium-68-Prostate-Specific Membrane Antigen Positron Emission Tomography Improves the Specificity of Bone Lesions

Accuracy of diffusion-weighted imaging in discriminating atypical vertebral haemangiomas from malignant masses in patients with vertebral lesions: a cross-sectional study

Purpose

Vertebral haemangiomas are incidental findings in imaging modalities. Atypical haemangiomas are haeman-giomas rich in vascular tissue, and they are found to be hypointense in T1 sequences and hyperintense in T2 sequences, mimicking the findings of metastatic lesions. In the present study we aim to evaluate the ability of diffusion- weighted imaging to differentiate these two groups of vertebral lesions.

Material and methods

In the present cross-sectional study, a total of 23 lesions were included, including 10 haemangiomas and 13 malignant lesions. Diffusion-weighted imaging was used to compare atypical haemangiomas and metastatic lesions. The apparent diffusion co-efficient was determined for each lesion, and then the mean of each group was calculated. The means were then compared. Receiver operating characteristic analysis was used to determine a cut-off ADC value to differentiate these lesions.

Results

The difference between the mean age of the two groups was not significant. The mean ADC value for atypical haemangiomas was 1884 ± 74 × 10^-6 mm²/s and 1008 ± 81 × 10^-6 mm²/s for the malignant lesions. The difference between the two groups was statistically significant (p < 10^-3). ROC curve analysis determined an ADC value of 958 × 10^-6 mm²/s to be able to differentiate between atypical haemangiomas and malignant lesions.

Conclusions

Diffusion-weighted MRI could be used to differentiate between atypical haemangiomas and malignant metastatic lesions.

Spinal Intraosseous Hibernoma: A Case Report and Review of Literature

Hibernoma is a rare benign tumor that arises from vestiges of brown fat. Spinal intraosseous hibernoma has only recently been described in the literature, and only 12 cases have been reported to date due to its extreme rarity. Here, we report the case of a patient who was incidentally diagnosed with an intraosseous hibernoma in the thoracic spine, following a diverse imaging work-up and pathologic confirmation. We correlate the clinical presentation and imaging features of our case with those of previously reported cases during our review of the literature.

The Dixon technique for MRI of the bone marrow

Dixon sequences are established as a reliable MRI technique that can be used for problem-solving in the assessment of bone marrow lesions. Unlike other fat suppression methods, Dixon techniques rely on the difference in resonance frequency between fat and water and in a single acquisition, fat only, water only, in-phase and out-of-phase images are acquired. This gives Dixon techniques the unique ability to quantify the amount of fat within a bone lesion, allowing discrimination between marrow-infiltrating and non-marrow-infiltrating lesions such as focal nodular marrow hyperplasia. Dixon can be used with gradient echo and spin echo techniques, both two-dimensional and three-dimensional imaging. Another advantage is its rapid acquisition time, especially when using traditional two-point Dixon gradient echo sequences. Overall, Dixon is a robust fat suppression method that can also be used with intravenous contrast agents. After reviewing the available literature, we would like to advocate the implementation of additional Dixon sequences as a problem-solving tool during the assessment of bone marrow pathology.