Imaging approach for jaw and maxillofacial bone tumors with updates from the 2022 World Health Organization classification

Jaw and maxillofacial bone lesions encompass a wide variety of both neoplastic and non-neoplastic pathologies.These lesions can arise from various tissues,including bone,cartilage,and soft tissue,each presenting distinct challenges in diagnosis and treatment.While some pathologies exhibit characteristic imaging features that aid in diagnosis,many others are nonspecific.This overlap often necessitates a multimodal imaging approach,combining techniques such as radiographs,computed tomography,and magnetic resonance imaging to achieve a diagnosis or narrow the diagnostic considerations.This article provides a comprehensive review of the imaging approach to jaw and maxillofacial bone tumors,including updates on the 2022 World Health Organization classification of these tumors.The relevant anatomy of the jaw and dental structures that is important for accurate imaging interpretation is discussed.

Endovascular treatment of extracranial vertebral artery stenosis

Percutaneous angioplasty and stenting for the treatment of extracranial vertebral artery(VA) stenosis seems a safe,effective and useful technique for resolving symptoms and improving blood flow to the posterior circulation,with a low complication rate and good long-term results.In patients with severe tortuosity of the vessel,stent placement is a real challenge.The new coronary balloon-expandable stents may be preferred.A large variability of restenosis rates has been reported.Drug-eluting stents may be the solution.After a comprehensive review of the literature,it can be concluded that percutaneous angioplasty and stenting of extracranial VA stenosis is technically feasible,but there is insufficient evidence from randomized trials to demonstrate that endovascular management is superior to best medical management.

Endovascular treatment of carotid cavernous sinus fistula: A systematic review

Carotid cavernous sinus fistulas are abnormal communications between the carotid system and the cavernous sinus. Several classification schemes have described carotid cavernous sinus fistulas according to etiology, hemodynamic features, or the angiographic arterial architecture. Increased pressure within the cavernous sinus appears to be the main factor in pathophysiology. The clinical features are related to size, exact location, and duration of the fistula, adequacy and route of venous drainage and the presence of arterial/venous collaterals. Noninvasive imaging (computed tomography, magnetic resonance, computed tomography angiography, magnetic resonance angiography, Doppler) is often used in the initial workup of a possible carotid cavernous sinus fistulas. Cerebral angiography is the gold standard for the definitive diagnosis, classification, and planning of treatment for these lesions. The endovascular approach has evolved as the mainstay therapy for definitive treatment in situations including clinical emergencies. Conservative treatment, surgery and radiosurgery constitute other management options for these lesions.

Value of liver computed tomography with iodixanol 270, 80 kVp and iterative reconstruction

AIM: To evaluate the image quality of hepatic multidetector computed tomography(MDCT) with dynamic contrast enhancement. METHODS: It uses iodixanol 270 mg/m L(Visipaque 270) and 80 kVp acquisitions reconstructed with sinogram affirmed iterative reconstruction(SAFIRE?) in comparison with a standard MDCT protocol. Fiftythree consecutive patients with known or suspected hepatocellular carcinoma underwent 55 CT examinations, with two different four-phase CT protocols. The first group of 30 patients underwent a standard 120 kVp acquisition after injection of Iohexol 350 mg/m L(Accupaque 350~?) and reconstructed with filtered back projection. The second group of 25 patients underwent a dual-energy CT at 80-140 kVp with iodixanol 270. The 80 kVp component of the second group was reconstructed iteratively(SAFIRE?-Siemens). All hyperdense and hypodense hepatic lesions ≥ 5 mm were identified with both protocols. Aorta and portal vessels/liver parenchyma contrast to noise ratio(CNR) in arterial phase, hypervascular lesion/liver parenchyma CNR in arterial phase, hypodense lesion/liver parenchyma CNR in portal and late phase were calculated in both groups.RESULTS: Aorta/liver and focal lesions altogether/liver CNR were higher for the second protocol(P = 0.0078 and 0.0346). Hypervascular lesions/liver CNR was not statistically different(P = 0.86). Hypodense lesion/liver CNR in the portal phase was significantly higher for the second group(P = 0.0107). Hypodense lesion/liver CNR in the late phase was the same for both groups(P = 0.9926).CONCLUSION: MDCT imaging with 80 kVp with iterative reconstruction and iodixanol 270 yields equal or even better image quality.

Role of ^(18)F-FDG PET/CT in pre and post treatment evaluation in head and neck carcinoma

Head and neck cancer(HNC) ranks as the 6th most common cancer worldwide, with the vast majority being head and neck squamous cell carcinoma(HNSCC). The majority of patients present with complicated locally advanced disease(typically stage Ⅲ and Ⅳ) requiring multidisciplinary treatment plans with combinations of surgery, radiation therapy and chemotherapy. Tumor staging is critical to decide therapeutic planning. Multiple challenges include accurate tumor localization with precise delineation of tumor volume, cervical lymph node staging, detection of distant metastasis as well as ruling out synchronous second primary tumors. Somepatients present with cervical lymph node metastasis without obvious primary tumors on clinical examination or conventional cross sectional imaging. Treatment planning includes surgery, radiation, chemotherapy or combinations that could significantly alter the anatomy and physiology of this complex head and neck region, making assessment of treatment response and detection of residual/ recurrent tumor very difficult by clinical evaluation and computed tomography(CT) or magnetic resonance imaging(MRI). 18F-2-fluoro-2-deoxyD-glucose positron emission tomography/CT(18F-FDG PET/CT) has been widely used to assess HNC for more than a decade with high diagnostic accuracy especially in detection of initial distant metastasis and evaluation of treatment response. There are some limitations that are unique to PET/CT including artifacts, lower soft tissue contrast and resolution as compared to MRI, false positivity in post-treatment phase due to inflammation and granulation tissues, etc. The aim of this article is to review the roles of PET/CT in both pre and post treatment management of HNSCC including its limitations that radiologists must know. Accurate PET/CT interpretation is the crucial initial step that leads to appropriate tumor staging and treatment planning.

Rarity among benign gastric tumors: Plexiform fibromyxoma-Report of two cases

Plexiform fibromyxoma is a very rare mesenchymal tumor of the stomach, found almost exclusively in the antrum/pylorus region. The most common presenting symptoms are anemia, hematemesis, nausea and unintentional weight loss, without sex or age predilection. We describe here two cases of plexiform fibromyxoma, involving a 16-year-old female and a 34-year-old male. Both patients underwent complete resection(R0) by distal gastrectomy and retrocolic gastrojejunostomy(according to Billroth 2); for both, the postoperative course was uneventful. Histology showed multiple intramural and subserosal nodules with characteristic plexiform growth, featuring bland spindle cells situated in an abundant myxoid stroma with low mitotic activity. Immunohistochemistry showed α-smooth muscle actin-positive spindle cells, focal positivity for CD10, and negative staining for KIT, DOG1, CD34, S100, β-catenin, STAT-6 and anaplastic lymphoma kinase. One of the cases showed focal positivity for h-caldesmon and desmin. Upon followup, no sign of disease was found. In the differential diagnosis of plexiform fibromyxoma, it is important to exclude the more common gastrointestinal stromal tumors as they have greater potential for aggressivebehavior. Other lesions, like neuronal and vascular tumors, inflammatory fibroid polyps, abdominal desmoid-type fibromatosis, solitary fibrous tumors and smooth muscle tumors, must also be excluded.

Dynamic Contrast-Enhanced Perfusion MR Imaging Measurements of Endothelial Permeability: Differentiation between Atypical and Typical Meningiomas

BACKGROUND: AND PURPOSE: The measurement of relative cerebral blood volume (rCBV) and the volume transfer constant (K(trans)) by means of dynamic contrast-enhanced (DCE) perfusion MR imaging (pMRI) can be useful in characterizing brain tumors. The purpose of our study was to evaluate the utility of these measurements in differentiating typical meningiomas and atypical meningiomas. METHODS: Fifteen patients with pathologically confirmed typical meningiomas and seven with atypical meningiomas underwent conventional imaging and DCE pMRI before resection.rCBV measurements were calculated by using standard intravascular

Quantitative comparison of cranial approaches in the anatomy laboratory: A neuronavigation based research method

AIMTo describe the development and validation of a novel neuronavigation-based method, which allows the quan-tification of the anatomical features that define anapproach, as well as real-time visualization of the surgicapyramid. METHODSThe method was initially developed with commercially-available hardware for coordinate collection （a digitizerand a frameless navigation system） and software forvolume rendering; dedicated neuronavigation software （ApproachViewer, part of GTx-UHN） was then developed. The accuracy of measurements and the possibility of volumetric rendering of surgical approaches simulated in a phantom were compared among three different methods and commercially-available radiological software. In the anatomy laboratory, ApproachViewer was applied to the comparative quantitative analysis of multiple neurosurgical approaches and was used by many surgeons who were untrained for the research method.RESULTSThe accuracy of ApproachViewer is comparable to com-mercially-available radiological software. In the anatomy laboratory, the method appears versatile. The system can be easily used after brief training. ApproachViewer allows for real-time evaluation and comparison of surgical approaches, as well as post-dissection analyses of collected data. The accuracy of the method depends on the navigation registration： with a 1-2 mm registration error, it is adequate for evaluation and comparison of most neurosurgical approaches.CONCLUSIONThis new research method and software allows semi-automated visualization, quantifcation, and comparison of neurosurgical approaches in the anatomy laboratory.

Susceptibility weighted imaging: Clinical applications and future directions

Susceptibility weighted imaging(SWI) is a recently developed magnetic resonance imaging(MRI) technique that is increasingly being used to narrow the differential diagnosis of many neurologic disorders. It exploits the magnetic susceptibility differences of various compounds including deoxygenated blood, blood products, iron and calcium, thus enabling a new source of contrast in MR. In this review, we illustrate its basic clinical applications in neuroimaging. SWI is based on a fully velocity-compensated, high-resolution, three dimensional gradientecho sequence using magnitude and phase images either separately or in combination with each other, in order to characterize brain tissue. SWI is particularly useful in the setting of trauma and acute neurologic presentations suggestive of stroke, but can also characterize occult low-flow vascular malformations, cerebral microbleeds, intracranial calcifications, neurodegenerative diseases and brain tumors. Furthermore, advanced MRI post-processing technique with quantitative susceptibility mapping, enables detailed anatomical differentiation based on quantification of brain iron from SWI raw data.

Arterial spin labeling in neuroimaging

Arterial spin labeling(ASL) is a magnetic resonance imaging technique for measuring tissue perfusion using a freely diffusible intrinsic tracer.As compared with other perfusion techniques,ASL offers several advantages and is now available for routine clinical practice in many institutions.Its noninvasive nature and ability to quantitatively measure tissue perfusion make ASL ideal for research and clinical studies.Recent technical advances have increased its sensitivity and also extended its potential applications.This review focuses on some basic knowledge of ASL perfusion,emerging techniques and clinical applications in neuroimaging.

Cerebrovascular reactivity mapping for brain tumor presurgical planning

This article provides a review of Blood Oxygen Level Dependent functional magnetic resonance imaging(BOLD fMRI)applications for presurgical mapping in patients with brain tumors who are being considered for lesion resection.Initially,the physical principle of the BOLD effect is discussed,followed by a general overview of the aims of presurgical planning.Subsequently,a review of sensorimotor,language and visual paradigms that are typically utilized in clinical fMRI is provided,followed by a brief description of studies demonstrating the clinical impact of preoperative BOLD fMRI.After this thorough introduction to presurgical fMRI,a detailed explanation of the phenomenon of neurovascular uncoupling(NVU),a major limitation of fMRI,is provided,followed by a discussion of the different approaches taken for BOLD cerebrovascular reactivity(CVR)mapping,which is an effective method of detecting NVU.We then include one clinical case which demonstrates the value of CVR mapping in clinical preoperative fMRI interpretation.The paper then concludes with a brief review of applications of CVR mapping other than for presurgical mapping.

脑铁定量的MRI检查:尸检证实性研究

目的以横向弛豫率R2和R2*评估脑铁含量,并与化学方法测定的脑铁含量进行对照分析。材料与方法本研究经地方伦理委员会批准。

Positron-emission tomography/computed tomography imaging in head and neck oncology:An update

Cancers of the head and neck account for more than half a million cases worldwide annually, with a significant majority diagnosed as squamous cell carcinoma(HNSCC). Imaging studies such as contrast-enhanced computed tomography(CT), magnetic resonance imaging(MRI) and ^(18)F-2-fluoro-2-deoxy-D-glucose positron-emission tomography/computed tomography(^(18)F-FDG PET/CT) are widely used to determine the presence and extent of tumors and metastatic disease, both before and after treatment. Advances in PET/CT imaging have allowed it to emerge as a superior imaging modality compared to both CT and MRI, especially in detection of carcinoma of unknown primary, cervical lymph node metastasis, distant metastasis, residual/recurrent cancer and second primary tumors, often leading to alteration in management. PET/CT biomarker may further provide an overall assessment of tumor aggressiveness with prognostic implications. As new developments emerged leading to better understanding and use of PET/CT in head and neck oncology, the aim of this article is to review the roles of PET/CT in both pre- and post-treatment management of HNSCC and PET-derived parameters as prognostic indicators.

镰状细胞疾病:颅内与颅外脑动脉血流速度的比值——初步经验

目的建立镰状细胞疾病的儿童大脑中动脉（VMCA）和颈内动脉终末端（VtICA）与颈内动脉（VICA）颅外段的血流速度比值的参考值。方法本项前瞻性研究经机构伦理委员会批准并且得到患儿父母的知情同意。68例[[38例女性；平均年龄（7．7＋3．3）岁，年龄范围2～14岁]携带血红蛋白HbSS基因的患儿，无神经系统及脑卒中病史，参与了本研究。最终有56例[平均年龄（8．0±3．3）岁；女26例1患儿采用MRA检查排除了颅内动脉狭窄，作为本研究资料。采用经颅多普勒彩超、

Simulated MRI Artifacts:Testing Machine Learning Failure Modes

Objective.Seven types of MRI artifacts,including acquisition and preprocessing errors,were simulated to test a machine learning brain tumor segmentation model for potential failure modes.Introduction.Real-world medical deployments of machine learning algorithms are less common than the number of medical research papers using machine learning.Part of the gap between the performance of models in research and deployment comes from a lack of hard test cases in the data used to train a model.Methods.These failure modes were simulated for a pretrained brain tumor segmentation model that utilizes standard MRI and used to evaluate the performance of the model under duress.These simulated MRI artifacts consisted of motion,susceptibility induced signal loss,aliasing,field inhomogeneity,sequence mislabeling,sequence misalignment,and skull stripping failures.Results.The artifact with the largest effect was the simplest,sequence mislabeling,though motion,field inhomogeneity,and sequence misalignment also caused significant performance decreases.The model was most susceptible to artifacts affecting the FLAIR(fluid attenuation inversion recovery)sequence.Conclusion.Overall,these simulated artifacts could be used to test other brain MRI models,but this approach could be used across medical imaging applications.

头颈部肿瘤中周围神经肿瘤扩散的影像学指证:^(18)F-FDG PET图像的指引及与CT和MR的相关性

神经周围扩散(PNS)是指肿瘤沿着大神经生长,是微观上周围神经侵袭的宏观表现。这种现象最常见于头颈部,但其发生率因组织学肿瘤亚型而异。PNS是由肿瘤细胞、神经和结缔间质间复杂分子相互作用的结果。尽管PNS对患者的预后和治疗有影响,但在临床上仍存在诊断不足。相较于确认为"金标准"的MRI来说,^(18)F-脱氧葡萄糖(FDG)PET在头颈部肿瘤PNS评估中的作用尚待探讨。在PNS患者中,^(18)F-FDG PET显示受累神经的异常,也显示失神经后出现的肌肉变化。在^(18)F-FDG PET上评估PNS需要相关神经通路的知识,并且可以通过与解剖成像的融合、图像的附加处理和临床背景的回顾来改进。

颅内血管壁MRI：原理和美国神经放射学学会专家共识

颅内血管壁磁共振成像是对常规血管造影方法（CT血管造影、磁共振血管造影或数字减影血管造影）的一种补充.该技术在缺血性卒中和颅内出血情况下有诸多潜在用途.尽管对颅内血管壁磁共振成像结果的理解还存在歧异,相关研究也还正在进行之中,但该技术已在许多中心应用于临床.本文代表美国神经放射学学会血管壁成像研究组为当前临床实践提供了专家共识推荐意见.

Imaging biomarkers in Parkinson’s disease and Parkinsonian syndromes:current and emerging concepts

Two centuries ago in 1817,James Parkinson provided the first medical description of Parkinson’s disease,later refined by Jean-Martin Charcot in the mid-to-late 19th century to include the atypical parkinsonian variants(also termed,Parkinson-plus syndromes).Today,Parkinson’s disease represents the second most common neurodegenerative disorder with an estimated global prevalence of over 10 million.Conversely,atypical parkinsonian syndromes encompass a group of relatively heterogeneous disorders that may share some clinical features with Parkinson’s disease,but are uncommon distinct clinicopathological diseases.Decades of scientific advancements have vastly improved our understanding of these disorders,including improvements in in vivo imaging for biomarker identification.Multimodal imaging for the visualization of structural and functional brain changes is especially important,as it allows a‘window’into the underlying pathophysiological abnormalities.In this article,we first present an overview of the cardinal clinical and neuropathological features of,1)synucleinopathies:Parkinson’s disease and other Lewy body spectrum disorders,as well as multiple system atrophy,and 2)tauopathies:progressive supranuclear palsy,and corticobasal degeneration.A comprehensive presentation of wellestablished and emerging imaging biomarkers for each disorder are then discussed.Biomarkers for the following imaging modalities are reviewed:1)structural magnetic resonance imaging(MRI)using T1,T2,and susceptibilityweighted sequences for volumetric and voxel-based morphometric analyses,as well as MRI derived visual signatures,2)diffusion tensor MRI for the assessment of white matter tract injury and microstructural integrity,3)proton magnetic resonance spectroscopy for quantifying proton-containing brain metabolites,4)single photon emission computed tomography for the evaluation of nigrostriatal integrity(as assessed by presynaptic dopamine transporters and postsynaptic dopamine D2 receptors),and cerebral perfusion,5)positron emission tomography for gauging nigrostriatal functions,glucose metabolism,amyloid and tau molecular imaging,as well as neuroinflammation,6)myocardial scintigraphy for dysautonomia,and 7)transcranial sonography for measuring substantia nigra and lentiform nucleus echogenicity.Imaging biomarkers,using the‘multimodal approach’,may aid in making early,accurate and objective diagnostic decisions,highlight neuroanatomical and pathophysiological mechanisms,as well as assist in evaluating disease progression and therapeutic responses to drugs in clinical trials.