Olfactory Neuroblastoma Is Not Always Located at the Roof of the Nasal Cavity.

Objectives: To evaluate the imaging characteristics of the tumor, emphasizing its location, and to determine the frequency of typical and atypical locations of olfactory neuroblastoma (ONB). Materials and Methods: We retrospectively reviewed the computed tomography and magnetic resonance imaging findings of patients with pathologically proven ONB between April 2000 and April 2023. Demographic information, chief complaints, tumor location, and tumor extension were extracted. Results: Of the 58 patients, 50 (86.2%) had the epicenter of the mass at the superior part of the nasal cavity, while eight patients (13.8%) had the epicenter at other atypical locations: seven patients (12.1%) at the middle part of the nasal cavity and one patient (1.7%) within both sphenoid sinuses. Conclusion: ONB is not always present in the upper part or the roof of the nasal cavity, and a significant number of ONBs are occasionally found in the rest of the nasal cavity and other atypical locations.

Internal Cerebral Vein in Susceptibility-Weighted Imaging: A Reliable Tool to Differentiate Among Calcification, Microbleed, and Gross Hemorrhage in Brain Tumors.

Background and objective Susceptibility-weighted imaging (SWI) sequence is crucial for brain MRI examinations, as it is equipped with a high sensitivity to detect calcification, microbleed, and gross hemorrhage. Intracranial venous structures such as the superior sagittal sinus (SSS) and cortical veins are used as reference structures in phase image SWI to differentiate diamagnetic and paramagnetic substances. Our study focuses on the internal cerebral vein (ICV) as another reliable reference structure. We aimed to analyze the diagnostic accuracy and detectability of calcification and hemorrhagic components in brain tumors using ICV, cortical veins, and SSS as references on phase image SWI, with CT scans for comparison. Material and methods A retrospective review of calcification and hemorrhagic components in brain tumors was conducted using MRI and CT from January 2017 to June 2023. Results The study included a total of 192 patients with brain tumors. For calcification components (63 cases), ICV and cortical veins as reference structures showed excellent sensitivity (96.8%), specificity (100%), and accuracy (98.9%). SSS demonstrated slightly lower detectability but maintained high sensitivity (96.5%), specificity (100%), and accuracy (98.8%) levels. No statistical differences were noted among these reference structures (p>0.05) and excellent interobserver agreement (Cohen's Kappa of 1) was observed. Conclusions The ICV is located in the central image, is large, without any nearby arteries, and is easy to identify using SWI phase images. Using the ICV as a reference to characterize intratumoral calcification, microbleed, and hemorrhage demonstrates high accuracy and detectability. With its findings of excellent interobserver agreement, our study will be of immense benefit to radiologists.

Diagnostic value of contrast-enhanced 3D FLAIR sequence in acute optic neuritis.

PURPOSE: Contrast-enhanced fluid-attenuated inversion recovery (FLAIR) sequence of the brain has the potential for detecting optic nerve abnormality. This study aimed to compare the diagnostic value of whole-brain contrast-enhanced three-dimensional FLAIR with fat suppression (CE 3D FLAIR FS) sequence in detecting acute optic neuritis to dedicated orbit MRI and clinical diagnosis. MATERIALS AND METHODS: Twenty-two patients with acute optic neuritis who underwent whole-brain CE-3D-FLAIR FS and dedicated orbit MRI were retrospectively included. The hypersignal FLAIR of the optic nerve on whole-brain CE-3D-FLAIR FS, enhancement, and hypersignal T2W on orbit images were assessed. The optic nerve to frontal white matter signal intensity ratio on CE-FLAIR FS was calculated as maximum signal intensity ratio (SIR) and mean SIR. RESULTS: Twenty-six hypersignals of optic nerves were found on CE-FLAIR FS from 30 pathologic nerves. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of CE FLAIR FS brain and dedicated orbital images for diagnosing acute optic neuritis were 77%, 93%, 96%, 65%, and 82% and 83%, 93%, 96%, 72%, and 86%, respectively. Optic nerve to frontal white matter SIR of the affected optic nerves was higher than that of normal optic nerves. Using a cutoff maximum SIR of 1.24 and cutoff mean SIR of 1.16, the sensitivity, specificity, PPV, NPV, and accuracy were 93%, 86%, 93%, 80%, and 89% and 93%, 86%, 93%, 86%, and 91%, respectively. CONCLUSION: The hypersignal of the optic nerve on whole-brain CE 3D FLAIR FS sequence has qualitative and quantitative diagnostic potential in patients with acute optic neuritis.

Intravoxel incoherent motion for differentiating residual/recurrent tumor from post-treatment change in patients with high-grade glioma.

PURPOSE: To investigate the diagnostic value of f derived from IVIM technique and to correlate it with rCBV derived from DSC for the differentiation of residual/recurrent tumor from post-treatment change in patients with high-grade glioma. MATERIALS AND METHODS: Patients who underwent MR imaging with IVIM and DSC studies for evaluation of high-grade glioma after standard treatment were enrolled in this retrospective study. For qualitative analysis, the f and rCBV maps were interpreted as hypoperfused or hyperperfused in each parameter. Quantitative analysis was performed using ROI analysis in f and rCBV parameters. The lesions were divided into residual/recurrent tumor and post-treatment change groups. RESULTS: Nineteen patients with high-grade glioma were included. In qualitative analysis, the f-map shows higher sensitivity (100.0%) than rCBV map (92.3%), while the rCBV map shows higher specificity (100.0%) than the f-map (83.3%). In quantitative analysis, the optimal cutoff values of 1.19 for f and 1.06 for rCBV are shown to provide high diagnostic value with high sensitivity (91.7%) for both parameters but slightly higher specificity of rCBV (85.7%) than f (71.4%). The correlation between f and rCBV was good with ICC of 0.810. CONCLUSION: The f value measured by IVIM technique, non-contrast perfusion technique, has high diagnostic performance and potential to be an alternative method to CBV measured by DSC for differentiation between residual/recurrent tumor and post-treatment change in patients with high-grade glioma.

Differentiation between aggressive and benign intracranial non-cavernous dural arteriovenous fistulas using cortical venous reflux on susceptibility weighted images.

PURPOSE: This study aimed to evaluate the ability of susceptibility-weighted imaging (SWI) to detect cortical venous reflux (CVR) in patients with intracranial non-cavernous dural arteriovenous fistulas (DAVFs), which can be helpful to differentiate benign and aggressive DAVFs. MATERIAL AND METHODS: Twenty-seven patients (8 women and 19 men) with 33 non-cavernous DAVFs were divided into benign and aggressive groups. Presence of CVR and pseudophlebitic pattern (PPP) and location of fistula on SWI were determined. Digital subtraction angiography was used as the reference standard. Interobserver agreement for the presence of CVR and PPP and location of DAVF on SWI was evaluated using the kappa statistic. Statistical comparisons between the benign and aggressive DAVFs were performed. RESULTS: Sensitivity, specificity, positive predictive value, and negative predictive value of SWI for detecting CVR was 73.7%, 85.7%, 87.5%, and 70.6%, respectively. Corresponding values for detecting PPP were 95.2%, 83.3%, 95.2%, and 83.3%, respectively. SWI correctly identified DAVF location in 78.9%. Prevalence rates of CVR and PPP on SWI were significantly higher in aggressive DAVFs than benign ones. CONCLUSION: SWI exhibited high sensitivity and specificity for detection of CVR, a characteristic used to differentiate benign and aggressive lesions. CVR and PPP on SWI are signs of aggressive DAVFs that guide to perform angiography confirmation and prompt treatment to avoid serious complication.

Usefulness of apparent diffusion coefficient values for distinguishing between squamous cell carcinoma and malignant salivary gland tumor of the head and neck.

PURPOSE: The aim of the study was to assess the usefulness of apparent diffusion coefficient (ADC) values for differentiating between SCC and malignant salivary gland tumors of the head and neck. MATERIALS AND METHODS: This retrospective cross-sectional study was conducted on 29 patients with SCCs and 10 patients with malignant salivary gland tumors who underwent pretreatment MRI of the head and neck. The minimum and average ADC values of the tumors were measured, with normalized tumor to spinal cord ADC ratios generated. Comparisons of ADC values and normalized ADC ratios between the two tumor types were performed using the unpaired t-test. RESULTS: The minimum and average ADC values and normalized average ADC ratios of SCCs (753.17 ± 214.47 × 10-6 mm2/s, 848.79 ± 250.13 × 10-6 mm2/s, and 0.92 ± 0.25, respectively) were significantly lower than those of malignant salivary gland tumors (1084.90 ± 242.60 × 10-6 mm2/s, 1305.90 ± 270.99 × 10-6 mm2/s, and 1.58 ± 0.31, respectively; all p < 0.001). A cutoff value of 1.31 for the normalized average ADC ratio was used to distinguish between SCCs and malignant salivary gland tumors and achieved an area under the curve of 0.93, sensitivity of 96.6%, specificity of 90%, and accuracy of 94.6%. CONCLUSION: ADC value measurement could help differentiate between SCCs and malignant salivary gland tumors.

Utility of dual energy CT in differentiating clot in acute ischemic stroke.

PURPOSE: Red blood cells (RBC)-poor thrombi in acute ischemic stroke (AIS) are associated with longer recanalization time for mechanical thrombectomy than RBC-rich thrombi. The purpose of the study was to differentiate between RBC-rich and RBC-poor thrombi using dual energy computed tomography (DECT). MATERIALS AND METHODS: This retrospective study was conducted on patients with acute arterial occlusion of anterior circulation who underwent DECT cerebral angiography, followed by mechanical thrombectomy with the pathological diagnosis of thrombi, dividing into RBC-rich and RBC-poor thrombi. The CT attenuation values and thrombus enhancement were measured in non-contrast scans and CTA phases at different energy levels and compared between RBC-rich and RBC-poor groups. RESULTS: Fourteen acute stroke patients were included in the study. There were 7 patients in RBC-rich group and 7 patients in RBC-poor group. The CT attenuation values of RBC-rich thrombi were significantly higher than those of RBC-poor thrombi at energy levels of 40, 50, 60, 70, and 80 KeV, with the most significant difference at 80 KeV (p = 0.032). A cutoff value of 44.1 Hounsfield units (HU) on 80 keV monoenergetic reconstructions was used to distinguish between RBC-rich and RBC-poor thrombi. It achieved an area under the curve (AUC) of 0.878, sensitivity of 85.7%, specificity of 100%, and accuracy of 92.9%. The degree of enhancement was higher in RBC-poor thrombi than in RBC-rich thrombi, without statistically significant difference. CONCLUSION: DECT could help differentiate between RBC-rich and RBC-poor thrombi by using CT attenuation values in non-contrast phase at lower energy levels (40-80 KeV).

Utility of high-resolution magnetic resonance vessel wall imaging in differentiating between atherosclerotic plaques, vasculitis, and arterial dissection.

PURPOSE: Differentiating between atherosclerosis, vasculitis, and dissection is a diagnostic challenge because of inconclusive findings on conventional imaging and some overlap in the vessel wall patterns. The aim of this study was to determine whether vessel wall MRI patterns can differentiate between these vasculopathies. METHODS: We retrospectively reviewed 3T high-resolution vessel wall imaging studies of patients diagnosed with atherosclerotic plaques, vasculitis, and dissection. The patterns of involvement, wall enhancement, and T1 and T2 signals, as well as the specific patterns, were assessed and compared between the three diseases. RESULTS: Fifty-nine patients with atherosclerosis (n = 33), vasculitis (n = 13), and dissection (n = 13) were enrolled. There were significant differences in the pattern of involvement between the three groups (P < 0.001), with concentric wall thickening in vasculitis patients (84.6%) and eccentric wall thickening in atherosclerosis (97%) and dissection (92.3%) patients. There was also a significant difference in the specific pattern (P < 0.001), with intimal flap (76.9%) and intramural hematoma (23.1%) in dissection patients and intraplaque hemorrhage (18.2%) in atherosclerosis patients. Furthermore, subgroup analysis showed a significant difference in the wall enhancement pattern between atherosclerosis and vasculitis patients (P < 0.05). Finally, there was a significant difference in the location of involvement between the three groups (P < 0.001). CONCLUSION: By using the pattern of involvement, wall enhancement, and specific patterns, vessel wall MRI can help differentiate between atherosclerosis, vasculitis, and dissection.

Susceptibility-weighted imaging is helpful in diagnosis of cerebral gnathostomiasis.

PURPOSE: To describe the role of SWI compared with other MR imaging sequences and CT in diagnosis of cerebral gnathostomiasis. MATERIALS AND METHODS: CTs and MRIs of patients with cerebral gnathostomiasis were retrospectively reviewed. The types of intracranial hemorrhage, including intraparenchymal hemorrhage (IPH), subdural hemorrhage (SDH), subarachnoid hemorrhage (SAH), and their locations were recorded. RESULTS: Four patients proven as cerebral gnathostomiasis were included. Intracranial hemorrhage was detected in all patients. There was IPH in all patients, SAH in 2 patients, and SDH in 2 patients. All patients (4/4) revealed hemorrhagic tracts which were very conspicuously seen on SWI. Other imaging sequences could also reveal hemorrhagic tracts in 3 patients (3/4) but are less conspicuously seen than SWI. None of the CT brains could detect hemorrhagic tracts. CONCLUSIONS: Intracranial hemorrhage associated with hemorrhagic tract, best demonstrated by SWI, is the key imaging characteristic in diagnosis of cerebral gnathostomiasis.

Prevertebral fat in Madelung disease mimicking cervical spine injury: A case report.

Madelung disease is defined by multiple symmetric fatty accumulations, usually involving the upper trunk, and may sometimes have excessive fat deposition in the prevertebral space. On magnetic resonance imaging (MRI), findings of fat that are hyperintense on T1w and T2w images, may simulate subacute hematoma and mimic cervical spine injury. This is the first reported case of Madelung disease with prevertebral fat deposition mimicking prevertebral hematoma found in cervical spine injury on MRI. Fat suppression techniques are helpful in order to differentiate between these two conditions, which should be taken into consideration during routine clinical practice.

Signal intensity pattern of the normal oculomotor nerve on contrast-enhanced 3D FLAIR at 3.0 T MRI.

PURPOSE: The aim of this study was to depict the signal intensity pattern of the normal oculomotor nerve demonstrated on contrast-enhanced three-dimensional fluid-attenuated inversion recovery images. MATERIALS AND METHODS: Eighty-one patients were included in the study. Contrast-enhanced three-dimensional fluid-attenuated inversion recovery images with magnetisation-prepared rapid acquisition were reconstructed and evaluated in the coronal plane. The signal intensity of the cisternal segment of the oculomotor nerve was graded into a visual scale of 1 to 5 as compared to the white matter, grey matter and the pituitary stalk. The signal intensity ratio of the oculomotor nerve was consequently measured. RESULTS: By using the visual scale, more than half of the oculomotor nerves showed higher signal intensity than the grey matter signal on contrast-enhanced three-dimensional fluid-attenuated inversion recovery images (59.3-80.2%). It can demonstrate a signal intensity similar to the pituitary stalk (14.8%) by visualisation. None of them showed signal intensity equal to the normal white matter signal. By signal intensity measurement, the mean signal intensity ratio of oculomotor nerves to white matter equals 1.54±0.20 (95% confidence interval (CI) 1.51-1.57); mean signal intensity ratio to grey matter equals 1.16±0.15 (95% CI 1.14-1.18); mean signal intensity ratio to the pituitary stalk equals 0.68±0.10 (95% CI 0.64-0.70). CONCLUSIONS: The normal oculomotor nerve visualised on contrast-enhanced three-dimensional fluid-attenuated inversion recovery images has a higher signal intensity than the white matter and may have a signal intensity similar to the grey matter or the pituitary stalk. The high signal intensity of the oculomotor nerve in contrast-enhanced three-dimensional fluid-attenuated inversion recovery should not be misinterpreted as a pathology.

Role of Quantitative Spectral CT Analysis for Differentiation of Orbital Lymphoma and Other Orbital Lymphoproliferative Disease.

PURPOSE: To investigate the value of quantitative parameters from spectral computed tomography for the differentiation of orbital lymphoma from other lymphoproliferative disease, including idiopathic orbital inflammatory disease (IOID) and IgG4-related disease (IgG4-RD). METHODS: Patients with orbital masses who underwent pre-treatment contrast-enhanced spectral CT were enrolled in this retrospective study. The subjects were divided into lymphoma and other orbital lymphoproliferative disease groups. Qualitative imaging features (margin, location, enhancement pattern, cranial nerves, soft tissue, and bone involvement) were reviewed. Quantitative parameters (iodine density and spectral attenuation curve slope) derived from spectral CT were measured. RESULTS: Eleven patients had orbital lymphoma and 11 had other orbital lymphoproliferative diseases (idiopathic orbital inflammatory disease (IOID), n = 5; IgG4-related disease (IgG4-RD), n = 6). Qualitative analysis showed no significant difference between the two groups. There was significantly higher iodine density in orbital lymphoma (1.24 ±â€¯0.24 mg/ml) than in IOID/IgG4-RD (0.83 ±â€¯0.23 mg/ml; P = 0.001). An iodine density threshold of 1.0 mg/ml gave sensitivity, specificity, and accuracy of 81.8%, with an area under the curve of 0.876 (P = 0.0003). Orbital lymphoma had a significantly higher iodine spectral attenuation curve slope (2.44 ±â€¯0.51 HU/keV) than IOID/IgG4-RD (1.66 ±â€¯0.47 HU/keV; P = 0.001). A threshold of 1.99 HU/keV for the spectral attenuation curve slope of 40-70 keV gave sensitivity, specificity, and accuracy of 81.8%, with an area under the curve of 0.884 (P = 0.0002). CONCLUSIONS: Quantitative spectral CT parameters can help differentiate orbital lymphoma from other orbital lymphoproliferative disease, with lymphoma having a significantly higher iodine density value and spectral attenuation curve slope than IOID/IgG4-RD.

Accuracy of apparent diffusion coefficient values and magnetic resonance imaging in differentiating suprasellar germinomas from chiasmatic/hypothalamic gliomas.

OBJECTIVE: The aim of this study was to differentiate suprasellar germinomas from chiasmatic/hypothalamic gliomas (CHGs) using apparent diffusion coefficient (ADC) values and magnetic resonance imaging (MRI) characteristics. MATERIALS AND METHODS: A cross-sectional study was conducted on 11 patients with suprasellar germinomas and 11 patients with CHGs who underwent pretreatment MRI. The ADC values (minimum and average ADC values) of the tumors were measured and the MRI characteristics were evaluated. RESULTS: The average and minimum ADC values of suprasellar germinomas were significantly lower than those of CHGs (p = 0.016 and 0.004 respectively). The selection of 941.15 × 10-6 mm2/s as a cutoff value of the minimum ADC value was used to differentiate suprasellar germinomas and CHGs; the best results were obtained with area under the curve of 0.889, sensitivity of 87.5%, specificity of 77.8% and accuracy of 82.4%. MRI characteristics suggested the diagnosis of suprasellar germinomas were T2W hypointensity and involvement of pituitary gland and/or stalk. MRI characteristics suggested the diagnosis of CHGs was higher degree of contrast enhancement and presence of macrocysts. CONCLUSION: ADC values have a role in differentiating suprasellar germinomas and CHGs, especially when imaging findings on conventional MRI are inconclusive. Furthermore, some MRI features are in favor of differentiation between these tumor entities including tumor location, cyst pattern, T2W hypointensity, degree of contrast enhancement, stalk and pituitary gland involvement.

Varicella zoster CNS vascular complications. A report of four cases and literature review.

This study explored the neurologic vascular complications of varicella zoster virus (VZV). We describe four patients presenting at our institution with neurologic involvement by VZV. MR and MRA studies of the intracranial arterial circulation in the head were read by board-certified radiologists using standard clinical procedures. On MRI, three patients had acute infarcts and in two instances irregularities and narrowings of vessels were visible. Many of these complications are recognized to be due to a vasculopathy affecting small or large vessels and resulting in cerebral infarctions and rarely hemorrhages. The pattern of cerebral infarction and vascular abnormalities is not specific and resembles those of vasculitis/vasculopathy from other causes. The central nervous system (CNS) vascular complications of VZV should be considered in the patients with simultaneous primary or prior VZV infection whose imaging studies show cerebral infarction and/or vasculitic appearing intracranial arteries.