Background: Inverted papilloma (IP) is an uncommon sino-nasal neoplasm with potentially distinctive MRI and CT features. The MR "striated" imaging pattern has been reported as a valuable MR imaging feature of IP. The purpose of this study was to validate the usefulness of this sign using detailed criteria of the sign itself. Results: All imaging findings were described for 16 patients in descriptive pattern. The nasal involvement showed highest prevalence followed by the maxillary sinus. The bony changes include remodeling and defects (n = 6), remodeling only (n = 4), and None (n = 6). Changes were severe 1/10, moderate in 3/10, and mild 5/10. Focal hyperostosis was seen in six. A striated pattern was "diffuse" in all 16 (100%) of the IPs; it followed a certain direction in all 16 patients: divergent (n = 6), convoluted (n = 2), and parallel (n = 8). Divergent growth from focal hyperostosis was seen (n = 4). Visibility of the sign was superior in T2 images (n = 11), superior in enhanced images (n = 3), and equal in both (n = 2). Conclusions: The striated pattern is a reliable MR imaging feature of sino-nasal IPs. Validity and usefulness of this sign can be emphasized by defining parameters of the signs itself including the following: diffusivity, direction of striations and relation to hyperostosis, and comparing visibility in both T2 and GAD-enhanced images, as well as combining this imaging signature with remolding bony changes < 1.5.
Background
Deep neck infections are showing resurgence in the current era and still pose threatening diagnosis. CT is the gold standard imaging modality; still, the reported low sensitivity and specificity was suggested in view of monophasic injection technique.
The purpose of the study was to discuss the diagnostic accuracy of CT with biphasic mode of injection using and a single scanning phase. The first 50–60 cc of IV contrast are injected at a slow rate of 1 cc/s to (tissue impregnation phase). The other 50–60 cc was injected at a high rate of 2 cc/sec, approximately 1 min after the first injection. The single phase of scanning is made followed by multi-planar image analysis of collection. Discrimination of abscess versus phlegmon is made according to described criteria.
Results
Radiological diagnosis was made of 64/66 cases of abscess and two cases only had phlegmon. The 64 cases of abscess underwent drainage by ENT surgeon showing correctly diagnosed drainable abscess in 59 out of 64 cases and 5 falsely diagnosed as abscess proved to be non-drainable phlegmon. The two patients with radiological diagnosis of non-drainable phlegmons were correctly diagnosed.
Conclusion
The study achieved a high accuracy of 92%. This is likely attributed to dual-phase technique that allows enhancement of the core of a phlegmon by slow interstitial phase, while combined dual injections allow enhancing the “rim enhancement sign” of abscess.
Background
CPA masses are uncommon lesions and usually have quite distinctive imaging features. Still, diagnosis can be challenging in some cases, carrying a significant impact on the choice of treatment and surgical approach. The purpose of this study was to validate the usefulness of MRI spectroscopy, diffusion, and susceptibility in the characterization of CPA masses with the emphasis on the two commonest lesions: schwannomas and meningiomas.
Results
The study included a total of 27 cases: schwannomas (n = 12), meningiomas (n = 7), epidermoid cysts (n = 2), two chondrosarcomas (n = 2), arachnoid cyst (n = 1), glomus tumor (n = 1), a meningeal metastasis (n = 1), and an endolymphatic sac tumor (n = 1). DWI revealed: eight lesions showed low ADC (<1 × 10−3 mm2/s), 15 lesions with intermediate ADC values (1–1.8 × 10−3 mm2/s), and 4 lesions had high ADC (>1.8 × 10−3 mm2/s.) Meningiomas showed low to intermediate ADC values while schwannomas showed intermediate to high ADC values. A cut-off ADC value of (1 × 10−3 mm2/s) is statistically significant in the differentiation of meningioma from schwannoma. A myoinositol peak was in all 12 schwannomas and single meningioma while 6 meningiomas displayed alanine peak, with a very good statistical significance. Remaining lesions revealed non-specific spectra. SWI made in 18 lesions revealed signal voids in three schwannomas and glomus.
Conclusions
Though MRI features of CPA masses are distinctive in most clinical settings; MRI spectroscopy, diffusion, and susceptibility can provide highly informative additional data in problematic cases. An intermediate to high ADC value plus myoinositol peak and signal voids of micro-bleeds are highly suggestive of schwannomas. This is in contrary to meningiomas displaying low to intermediate ADC and an alanine peak with no micro-bleeds. The less common lesions revealed non-specific data.
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