Skull base osteomyelitis: clinical and radiologic analysis of a rare and multifaceted pathological entity.

Skull base osteomyelitis (SBO) is a potentially life-threatening inflammation of cranial base bony structures of variable origin. Criteria for diagnosis and treatment are still controversial. Demographics, predisposing factors, symptoms, imaging, and clinical, laboratory, histological, and microbiological data of patients managed for SBO at the University Hospital of Brescia (ASST Spedali Civili) between 2002 and 2017 were retrospectively reviewed. Patients were included in different etiological groups. The topographic distribution of magnetic resonance (MR) abnormalities was recorded on a bi-dimensional model of skull base, on which three different patterns of inflammatory changes (edematous, solid, or necrotic) were reported. In patients with a history of radiotherapy, the spatial distribution of SBO was compared with irradiation fields. The association between variables and etiological groups was verified with appropriate statistical tests. A classification tree analysis was performed with the aim of inferring a clinical-radiological diagnostic algorithm for SBO. The study included 47 patients, divided into 5 etiological groups: otogenic (n = 5), radio-induced (n = 16), fungal (n = 14), immune-mediated (n = 6), and idiopathic (n = 6). At MR, five types of topographical distribution were identified (central symmetric, central asymmetric, orbital apex, sinonasal, maxillary). In patients with a history of radiotherapy, the probability to develop SBO was significantly increased in areas receiving the highest radiation dosage. The analysis of patients allowed for design of a classification tree for the diagnosis of SBO. The integration of clinical and radiologic information is an efficient strategy to categorize SBO and potentially guide its complex management.

Early Postoperative Magnetic Resonance in the Diagnosis of Persistent Juvenile Angiofibroma.

OBJECTIVES/HYPOTHESIS: Despite improvements in the treatment of juvenile angiofibroma (JA), the rate of persistence (pJA) is still not negligible. In the present study, we assessed the value of early postoperative magnetic resonance imaging (MRI) in depicting unintentional pJAs and designed a MRI-driven decisional flow-chart for pJA management and follow-up. STUDY DESIGN: Observational study. METHODS: Patients undergoing early postoperative MRI after endoscopic resection of JA in the Unit of Otorhinolaryngology - ASST Spedali Civili, University of Brescia from 2007 to 2017 were enrolled. MRI was defined as negative or positive based on defined radiological criteria. The diagnostic performance of MRI was evaluated. RESULTS: The analysis included 26 patients, with a mean age of 16.5 years (range, 11-25). Early MRI was negative for pJA in 21 (80.8%) patients and positive in five (19.2%). No patient with a negative finding was found positive at subsequent follow-up MRIs. The accuracy of a positive finding was confirmed by pathologic examination (three cases) or follow-up MRIs (two cases). The diagnostic performance of MRI was excellent with sensitivity and specificity of 100%. An MRI-driven flow-chart for pJA management and follow-up was designed. CONCLUSIONS: Early postoperative MRI demonstrated a high diagnostic accuracy in the detection of unintentional pJA. Our MRI-driven strategy and decisional flow-chart could aid in the decision-making process in the management of pJA and definition of postoperative surveillance. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E2436-E2441, 2021.

Posttreatment Imaging Surveillance.

Posttreatment imaging surveillance in patients treated for anterior skull base tumors is a multifaceted issue which - as a first step - requires tailoring of the selection of imaging technique and acquisition protocol to the clinical scenario. As a general rule, acute symptoms suggesting the onset of a complication of treatment require prompt diagnosis through an easily accessible technique, such as CT; on the other hand, monitoring recurrences in asymptomatic patients is best achieved with MRI, exploiting the inherently higher contrast resolution. The interpretation of follow-up imaging studies is challenging. First of all, it is essential to be aware of specific characteristics of the natural history that may differ significantly between histologies, influencing the pattern and timing of recurrences. Additionally, resection of the lesion and reconstruction of the defect (as well as radiation treatment) produce complex anatomical changes, which may mislead inexperienced radiologists; this concept emphasizes the centrality of collecting accurate information on treatment modalities and procedures applied before scanning in each patient. This enables the pattern of expected posttreatment changes to be anticipated and, consequently, recurrences or complications to be more easily identified.

An additional challenge for head and neck radiologists: anatomic variants posing a surgical risk - a pictorial review.

Anatomic variants in the head and neck are quite numerous and occur frequently: a minority of them increase the risk of complications during surgical procedures and may be visualized on cross-sectional images. As some of these complications are potentially fatal, awareness (and accurate reporting) of such variants is a basic responsibility of radiologists, particularly when surgery in the pertinent anatomic area is under consideration.

Validation of a free software for unsupervised assessment of abdominal fat in MRI.

PURPOSE: To demonstrate the accuracy of an unsupervised (fully automated) software for fat segmentation in magnetic resonance imaging. The proposed software is a freeware solution developed in ImageJ that enables the quantification of metabolically different adipose tissues in large cohort studies. METHODS: The lumbar part of the abdomen (19cm in craniocaudal direction, centered in L3) of eleven healthy volunteers (age range: 21-46years, BMI range: 21.7-31.6kg/m2) was examined in a breath hold on expiration with a GE T1 Dixon sequence. Single-slice and volumetric data were considered for each subject. The results of the visceral and subcutaneous adipose tissue assessments obtained by the unsupervised software were compared to supervised segmentations of reference. The associated statistical analysis included Pearson correlations, Bland-Altman plots and volumetric differences (VD%). RESULTS: Values calculated by the unsupervised software significantly correlated with corresponding supervised segmentations of reference for both subcutaneous adipose tissue - SAT (R=0.9996, p<0.001) and visceral adipose tissue - VAT (R=0.995, p<0.001). Bland-Altman plots showed the absence of systematic errors and a limited spread of the differences. In the single-slice analysis, VD% were (1.6±2.9)% for SAT and (4.9±6.9)% for VAT. In the volumetric analysis, VD% were (1.3±0.9)% for SAT and (2.9±2.7)% for VAT. CONCLUSIONS: The developed software is capable of segmenting the metabolically different adipose tissues with a high degree of accuracy. This free add-on software for ImageJ can easily have a widespread and enable large-scale population studies regarding the adipose tissue and its related diseases.

High-resolution-cone beam tomography analysis of bone microarchitecture in patients with acromegaly and radiological vertebral fractures.

Vertebral fractures are an emerging complication of acromegaly but their prediction is still difficult occurring even in patients with normal bone mineral density. In this study we evaluated the ability of high-resolution cone-beam computed tomography to provide information on skeletal abnormalities associated with vertebral fractures in acromegaly. 40 patients (24 females, 16 males; median age 57 years, range 25-72) and 21 healthy volunteers (10 females, 11 males; median age 60 years, range: 25-68) were evaluated for trabecular (bone volume/trabecular volume ratio, mean trabecular separation, and mean trabecular thickness) and cortical (thickness and porosity) parameters at distal radius using a high-resolution cone-beam computed tomography system. All acromegaly patients were evaluated for morphometric vertebral fractures and for mineral bone density by dual-energy X-ray absorptiometry at lumbar spine, total hip, femoral neck, and distal radius. Acromegaly patients with vertebral fractures (15 cases) had significantly (p < 0.05) lower bone volume/trabecular volume ratio, greater mean trabecular separation, and higher cortical porosity vs. nonfractured patients, without statistically significant differences in mean trabecular thickness and cortical thickness. Fractured and nonfractured acromegaly patients did not have significant differences in bone density at either skeletal site. Patients with acromegaly showed lower bone volume/trabecular volume ratio (p = 0.003) and mean trabecular thickness (p < 0.001) and greater mean trabecular separation (p = 0.02) as compared to control subjects, without significant differences in cortical thickness and porosity. This study shows for the first time that abnormalities of bone microstructure are associated with radiological vertebral fractures in acromegaly. High-resolution cone-beam computed tomography at the distal radius may be useful to evaluate and predict the effects of acromegaly on bone microstructure.