Imaging of skull base pathologies: Role of advanced magnetic resonance imaging techniques

[Simultaneous occurrence of facial neurinoma in internal auditory canal and middle ear paraganglioma in patient. Unusual combination and difficult surgical task]

CLINICAL CASE

The 59-year-old patient complained of hearing loss on the left, ear murmur for a long time, periodic pain and discomfort in the left ear, dizziness for 6 months. She was found to have concurrent vestibular schwannoma in the internal auditory canal and temporal bone paraganglioma. Both tumors were removed in one operation. The schwannoma was removed by translabirinth access due to preoperative deafness, while the glomus tumor was removed during this access. Postoperative biopsy showed the presence of two unrelated diseases: paraganglioma (ICD-0 code 8690/3) and schwannoma (ICD-0 code 9560/0).

Capillary Hemangioma of the Maxillary Sinus: A Rare Cause of Massive Life-Threatening Epistaxis

Hemangioma of the paranasal sinus is an infrequent condition. Two types of hemangioma are present at the nose; cavernous and capillary. Capillary hemangioma is rare in the sinonasal tract. Patients presented with massive epistaxis should think of nasal hemangioma. Resuscitation of patients is important and urgent Computerized Tomography scans should be performed which will help character and extension of any mass present at the nasal cavity. Initial nasal packing may help to prevent bleeding. We report a case of capillary hemangioma of a 30-year lady present with massive epistaxis initially controlled by Nasal packing. Her CT scan shows a homogenous mass at left maxillary sinuses and underwent left endoscopic sphenopalatine artery ligation and removal of the mass.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-023-04046-z.

Preoperative Magnetic Resonance Elastography (MRE) of Skull Base Tumours: A Review

Conventional magnetic resonance imaging (MRI) can detect tumors consistency, but it can't predict tumor stiffness or adherence of the tumor to nearby structures. Magnetic resonance elastography (MRE) is a known non-invasive MRI based imaging technique used to assess the viscoelasticity of the tissues particularly liver fibrosis. This study discussed the importance of preoperative MRE in skull base tumors and the future implications of this new imaging modality. We did review of the English literature (by searching PubMed) regarding the use of MRE in preoperative assessment of skull base tumours stiffness and adherence to surrounding tissues. Recent research demonstrated that MRE can detect the stiffness and adherence of skull base tumors to surrounding structures by recording the spread of mechanical waves in the different tissues. In addition to non-radiation exposure, this technique is fast and can be incorporated into the conventional (MRI) study. MRE can palpate skull base tumours by imaging, allowing the stiffness of the tumour to be assessed. Preoperative assessment of brain tumours consistency, stiffness, and adherence to surrounding tissues is critical to avoid injury of important nearby structures and better preoperative patient counselling regarding surgical approach (endoscopic or open), operative time, and suspected surgical complications. However, the accuracy of MRE is less in small and highly vascular tumors. Also, MRE can't accurately detect tumour-brain adherence, but the new modality (slip-interface imaging) can. Hence, adding MRE to the conventional MRI study may help in preoperative diagnosis and treatment of skull base tumours.

Neurosurgical Management of Cerebrospinal Tumors in the Era of Artificial Intelligence : A Scoping Review

Central nervous system tumors are identified as tumors of the brain and spinal cord. The associated morbidity and mortality of cerebrospinal tumors are disproportionately high compared to other malignancies. While minimally invasive techniques have initiated a revolution in neurosurgery, artificial intelligence (AI) is expediting it. Our study aims to analyze AI's role in the neurosurgical management of cerebrospinal tumors. We conducted a scoping review using the Arksey and O'Malley framework. Upon screening, data extraction and analysis were focused on exploring all potential implications of AI, classification of these implications in the management of cerebrospinal tumors. AI has enhanced the precision of diagnosis of these tumors, enables surgeons to excise the tumor margins completely, thereby reducing the risk of recurrence, and helps to make a more accurate prediction of the patient's prognosis than the conventional methods. AI also offers real-time training to neurosurgeons using virtual and 3D simulation, thereby increasing their confidence and skills during procedures. In addition, robotics is integrated into neurosurgery and identified to increase patient outcomes by making surgery less invasive. AI, including machine learning, is rigorously considered for its applications in the neurosurgical management of cerebrospinal tumors. This field requires further research focused on areas clinically essential in improving the outcome that is also economically feasible for clinical use. The authors suggest that data analysts and neurosurgeons collaborate to explore the full potential of AI.

External auditory canal and middle ear tumors: characterization by morphology and diffusion features on CT and MRI

PURPOSE

To explore the value of morphology and diffusion features on CT and MRI in the characterization of external auditory canal and middle ear tumors (EAMETs).

METHODS

Forty-seven patients with histologically proved EAMETs (23 benign and 24 malignant) who underwent CT and MRI were retrospectively analyzed in this study. CT and MRI characteristics (including size, shape, signal intensity, border, enhancement degree, and bone changes) and apparent diffusion coefficient (ADC) value were analyzed and compared between benign and malignant EAMETs. Logistic regression, receiver operating characteristic (ROC) curve, and Delong test were performed to assess the diagnostic performance.

RESULTS

Compared with benign tumors, the malignant EAMETs are characterized by irregular shape, ill-defined border, invasive bone destruction, and intense enhancement (all p < 0.05). There were no significant differences on the size and signal intensity between benign and malignant tumors. The ADC value of malignant tumors were (879.96 ± 201.15) × 10^-6 mm²/s, which was significantly lower than benign ones (p < 0.05). Logistic regression demonstrates the presence of ill-defined margin, invasive bone destruction, and low ADC value (≤ 920.33 × 10^-6 mm²/s) have significant relationship with malignant EAMETs. The combination of characterization by morphology and diffusion features on CT and MRI can further improve the diagnostic efficiency when compared with morphology and diffusion features alone (both p < 0.05).

CONCLUSION

Some CT and MRI characteristics are helpful in identifying malignant EAMETs from benign ones (especially ill-defined margin, invasive bone destruction, and low ADC value), and the combination of morphology and diffusion features on CT and MRI has best diagnostic efficiency for discriminating these two entities.

Advanced Magnetic Resonance Imaging of the Skull Base

Magnetic resonance (MR) imaging is a crucial tool for evaluation of the skull base, enabling characterization of complex anatomy by utilizing multiple image contrasts. Recent technical MR advances have greatly enhanced radiologists' capability to diagnose skull base pathology and help direct management. In this paper, we will summarize cutting-edge clinical and emerging research MR techniques for the skull base, including high-resolution, phase-contrast, diffusion, perfusion, vascular, zero echo-time, elastography, spectroscopy, chemical exchange saturation transfer, PET/MR, ultra-high-field, and 3D visualization. For each imaging technique, we provide a high-level summary of underlying technical principles accompanied by relevant literature review and clinical imaging examples.

Heavily calcified parapharyngeal space mesenchymal chondrosarcoma: Imaging and pathological findings and a review of the literature

Parapharyngeal space (PPS) masses are relatively rare lesions of the head and neck, and account for 0.5-1.5% of head and neck lesions. The most common lesion to occur in the PPS is a benign salivary neoplasm, typically pleomorphic adenoma either from the deep parotid or from ectopic parotid tissue rests within the PPS. A calcified or ossified mass in this location is exceedingly rare, but a calcified variant of pleomorphic adenoma has been reported. In this study, we present a patient with a heavily calcified PPS mesenchymal chondrosarcoma with an unusual presentation. We discuss the imaging and pathologic findings followed by a review of the current literature.

Additional diagnostic role of MRI spectroscopy, diffusion and susceptibility imaging in differentiation of CPA masses: our experience with emphasis on schwannomas and meningiomas

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.

Clinical-radiological-pathological correlation of cavernous sinus hemangioma: Incremental value of diffusion-weighted imaging

AIM

To elucidate the clinical, magnetic resonance imaging (MRI), pathological features of these lesions and asses the incremental value of diffusion-weighted imaging (DWI) in diagnosing them.

METHODS

Fifteen consecutive patients (11 females and 4 males; mean age 40.93 years; age range 13-63 years) with cavernous sinus hemangiomas (CSH) who underwent examination between November 2008 and May 2016 were included for the analysis. MRI, clinical and surgical findings of each patient was retrospectively reviewed. DWI were also analysed and mean-apparent diffusion coefficient (ADC) value was calculated. Eleven patients underwent surgical removal of the lesion and 2 patients had biopsy only. Diagnosis of CSH was confirmed histologically in 13 patients.

RESULTS

Eleven patients (73%) presented with headaches and 10 (66%) had cranial nerve involvement. Extra cavernous sinus extension was noted in 14 (94%). Surgery was performed in 13 (87%) and post-operative radiation was given to 4 (28%) patients. Thirteen patients remained asymptomatic on follow up. Three conspicuous imaging features were highly suggestive of the diagnosis: Lack of diffusion restriction (100%), homogeneous hyperintensity on T2 weighted image sequences (93.3%) and intense post-contrast enhancement (100%). The mean ADC was 1.82 × 10^-3 ± 0.2186 cm²/s.

CONCLUSION

T1-weighted hypointensity with homogeneous hyperintensity on T2-weighted sequences, intense enhancement and absence of hemosiderin within the lesion on GRE sequence favour the diagnosis. Facilitated diffusion on DWI differentiates CSH from other solid cavernous sinus lesions and significantly improves the diagnostic accuracy, a critical factor for planning surgery.

Role of diffusion-weighted imaging in skull base lesions: A pictorial review

Skull base lesions can be related to wide number of pathologies including infections, benign and malignant tumors. Accurate diagnosis and differentiation between these entities is important for prompt and appropriate treatment. However, computed tomography and routine magnetic resonance imaging techniques only provide information on the extent of the lesions, with limited ability to differentiate between benign and malignant lesions. Diffusion-weighted imaging can help in many such situations by providing additional information, including help in differentiating benign from malignant lesions, so that appropriate treatment can be initiated. In this review article, we illustrate the imaging findings of the spectrum of skull base lesions, emphasizing the role of diffusion-weighted imaging in this domain.