SUMMARY: Texture analysis is a continuously evolving, noninvasive radiomics technique to quantify macroscopic tissue heterogeneity indirectly linked to microscopic tissue heterogeneity beyond human visual perception. In recent years, systemic oncologic applications of texture analysis have been increasingly explored. Here we discuss the basic concepts and methodologies of texture analysis, along with a review of various MR imaging texture analysis applications in glioma imaging. We also discuss MR imaging texture analysis limitations and the technical challenges that impede its widespread clinical implementation. With continued advancement in computational processing, MR imaging texture analysis could potentially develop into a valuable clinical tool in routine oncologic imaging.

Magnetic resonance (MR) imaging plays an important role in the evaluation of bacterial and tuberculous spondylodiscitis and associated complications. Owing to its high sensitivity and specificity, it is a powerful diagnostic tool in the early diagnosis of ongoing infections, and thus provides help in prompt initiation of appropriate, therapy which may be medical or surgical, by defining the extent of involvement and detection of complications such as epidural and paraspinal abscesses. More specifically, MR imaging helps in differentiating bacterial from tuberculous infections and enables follow up of progression or resolution after appropriate treatment. However, other non-infectious pathology can demonstrate similar MR imaging appearances and one should be aware of these potential mimickers when interpreting MR images. Radiologists and other clinicians need to be aware of these potential mimics, which include such pathologies as Modic type I degenerative changes, trauma, metastatic disease and amyloidosis. In this pictorial review, we will describe and illustrate imaging findings of bacterial and tuberculous spondylodiscitis, their complications and non-infectious pathologies that mimic these spinal infections.

Purpose: Spinal sarcoidosis, referring to involvement of the spine in sarcoidosis, is relatively rare and may mimic other neurological disease affecting the spine. The authors present a clinic radiological review of 18 spinal sarcoidosis patients who presented to a tertiary hospital, with emphasis on initial imaging and radiological response to treatment. Materials and methods: We retrospectively reviewed our departmental imaging archives over a 15-year period and found 49 cases of neurosarcoidosis out of which 18 patients had spinal magnetic resonance imaging. Results: Approximately 72% (13/18) of the neurosarcoidosis patients showed some form of spinal involvement. The clinical, epidemiological and imaging data were reviewed for these 13 patients at presentation and follow-up. The findings on magnetic resonance imaging included leptomeningeal enhancement (61%), pachymeningeal (23%), intramedullary enhancing lesions (38%) and bony involvement (15%). The cervical segment was most frequently involved followed by the thoracic segment. Involvement was often long segment (4.2 spinal segments) with proclivity for the dorsal cord. Mean follow-up was 23.2 months. A complete or near-complete radiological response occurred in 66% while partial response was seen in 25% patients. Four patients had isolated central nervous system involvement including one with isolated spinal cord involvement. On diffusion-weighted imaging, the apparent diffusion coefficient of intramedullary lesions was increased compared to normal-appearing cord on baseline and subsequent follow-up scans. Conclusions: Spinal sarcoidosis was previously considered uncommon but is being increasingly recognized with widespread use of magnetic resonance imaging. Proclivity for dorsal surface involvement is characteristic, although not necessarily pathognomonic. Also, quantitative diffusion studies may serve as a biomarker for the disease activity and parenchymal injury.

Cerebrovascular complications of tuberculous meningitis (TBM) are associated with increased morbidity and mortality. We retrospectively reviewed clinicoradiological findings of 90 TBM patients who presented to a tertiary care hospital, with emphasis on frequency and distribution of infarcts on diffusion imaging and pattern of vascular involvement on magnetic resonance (MR) angiography (MRA). MR images of 90 TBM patients at presentation (2012–2018) were coanalyzed by two radiologists for tuberculomas, leptomeningeal enhancement (LM), hydrocephalus, infarct and vascular abnormalities. Infarcts were categorized based on location (“tubercular” (TB) or “ischemic” zones) and arterial supply (perforators and cortical branches). Clinical and laboratory findings were correlated with imaging data. Ninety TBM patients (age 10–82 years) were enlisted after application of inclusion criteria. Tuberculomas were most common (100%) followed by LM (84.4%), cerebral infarcts (57.7%) and hydrocephalus (29%). Location-wise, 35% infarcts were in ischemic, 13% in TB and 15% in both zones. According to arterial supply, infarcts equally (50%) involved perforators from the lateral lenticulostriate and posterior cerebral (PCA)/basilar artery (BA) followed by medial lenticulostriate arteries (23%). MRA was available in 74.4% and abnormal in 43.2%. The middle cerebral artery was frequently involved (76%) followed by the anterior cerebral artery (38%), internal carotid artery (31%), PCA and BA. Six had diffuse narrowing with a paucity of distal vessels. Cerebral infarction was associated with hydrocephalus (p = .0019) and vasculitis (p < .001). In TBM, strokes are common and mainly involve the perforators and cortical branches. MR is the imaging modality of choice for early diagnosis and timely management.

SUMMARY: Sinonasal and skull base tumors are a heterogeneous group of neoplasms with considerable histologic variation and overlapping imaging features. In 2022, the World Health Organization updated the head and neck tumor classification, further emphasizing the importance of molecular data and genetic alterations in sinonasal neoplasms. The changes include the addition of new entities and discussion of emerging entities, as well as changes to the taxonomy and characterization of tumors. The new classification focuses on entities that develop in these sites either exclusively (eg, olfactory neuroblastoma) or most frequently. Another change includes reduction in the number of categories by creating separate category-specific chapters for soft-tissue, hematolymphoid, and neuroectodermal lesions. In this review, we briefly discuss the various categories in the new classification with a more detailed description of the 2 new entities (SWItch/Sucrose Non-Fermentable complex–deficient sinonasal carcinomas and human papillomavirus–related multiphenotypic sinonasal carcinoma). We also highlight the emerging entities including IDH–mutant sinonasal malignancies and DEK-AFF2 carcinoma, presently classified as sinonasal undifferentiated carcinoma and nonkeratinizing squamous cell carcinoma, respectively.