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01:50 CET
RC 108 - Differential diagnoses you don't want to miss
Head and Neck General Radiology
Wednesday, February 28, 08:30 - 10:00
Room: N
Moderator: M. R. Eriksen (Stavanger/NO)

A. Differential diagnoses of orbital masses
V. Chong; Singapore/SG
Learning Objectives

1. To become familiar with the anatomy of the orbit.
2. To learn which imaging technique to use.
3. To understand the typical imaging appearance of orbital masses.


The approach to orbital mass analysis follows two basic rules. The first rule emphasizes the general fact that diseases arise from pre-existing tissues or structures unique to different spaces in the orbit. The second rule highlights exceptions to the general rule. For example, metastatic or other systemic diseases may involve the orbit, while trans-spatial pathological processes such as infiltrative lesions may affect multiple compartments simultaneously or metachronously. The orbit can be divided (by the muscle cone) into an intra-conal and an extra-conal compartment. Structures in the intra-conal compartment include the optic nerve/sheath complex and the surrounding fibro-fatty tissues, small vessels and small nerve branches. The contents of the extra-conal space include the lacrimal gland, cranial nerves (V1 and V2) and the periosteum of the orbit. Hence, knowledge of the applied anatomy of the orbit with a working knowledge of commonly seen diseases is a prerequisite for generating lists of differential diagnoses. The analysis of orbital masses should always be carried out in the clinical context of the patient. Tentative as well as definitive diagnosis can often be made with reference to the clinical information. For example, a lesion with unusual morphology or location can be tentatively diagnosed as metastatic disease in the presence of a history of malignancy elsewhere. In conclusion, the integration of knowledge of orbital anatomy, pathology and clinical information provides the basis of sound radiological differential diagnoses for further patient management.

B. Differential diagnoses of the jaw masses
C. Czerny; Vienna/AT
Learning Objectives

1. To become familiar with the anatomy of the jaw.
2. To learn which imaging technique to use.
3. To understand the typical imaging appearance of jaw lesions.


Cystic and tumorous pathologies of the jaws can be imaged with cone-beam CT, CT and MRI. These pathologies include, e.g. in most cases inflammation or tumours. PET-CT or PET-MR may also be used. CT may be used without or with the i.v. application of iodinated contrast material dependent on the pathology. The images can be documented in soft-tissue- and/or bone-window-level setting. Imaging planes are usually axial, coronal or sagittal depending on the pathology. MRI has the advantage of higher soft tissue contrast and the possibility of using different sequences. Depending on the pathology, e.g. fat-suppressed T2-weighted, diffusion-weighted, T1-weighted sequences before and after the i.v. use of gadolinium and T1-weighted contrast-enhanced sequences with fat suppression are used. The imaging planes may be axial, coronal or sagittal. In this refresher course, the normal anatomy of the jaw, variants mimicking osteolytic or osteoblastic lesions, and cystic and tumorous pathologies of the jaws will be shown, and the imaging characteristics will be explained.

C. Differential diagnoses of soft tissue masses
D. Farina; Brescia/IT
Learning Objectives

1. To become familiar with the anatomy.
2. To learn which imaging technique to use.
3. To understand the typical imaging appearance of soft tissue masses.


Soft tissue masses of the supra and infrahyoid neck are a rather heterogeneous group of tumours, classified by WHO in nine categories, based on their histologic differentiation: adipocytic, fibroblastic or myofibroblastic, fibrohistiocytic, smooth muscle, skeletal muscle, vascular, pericytic, and chondro-osseous tumours, and tumours of uncertain differentiation. Based on their clinical behavior and history such tumours may be described as benign, malignant or intermediate, the latter further subclassified as locally invasive or metastatising at distant sites. US is generally the first imaging step in infrahyoid neck lesions; MDCT or MRI are mandatory in suprahyoid masses, but are also needed to better define the deep extent and anatomic relationships of infrahyoid tumours. In many cases, imaging findings are overlapping and insufficient for tumour characterisation; nonetheless, some specific clues may orient the differential diagnosis. Site of origin of the lesion is probably the first brick in the wall; therefore, knowledge of the space-based neck anatomy is essential prerequisite. Patient’s age, size and number of lesions, presence and pattern of calcifications are useful additional details. Some specific density or signal intensity patterns may cut the list of differentials, whereas the potential role of the additional information provided by DWI-MRI or dual-energy CT is far from being fully elucidated. However, it is clearly assumed that imaging diagnosis does not replace pathologic assessment, which in a significant number of cases can be accurately obtained with FNA.

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