Читать книгу Salivary Gland Pathology - Группа авторов - Страница 105

 Among the choices for imaging of the salivary glands, CT with IV contrast is the most commonly performed procedure. Coronal and sagittal reformatted images provide excellent evaluation soft tissues in orthogonal planes. The latest generation MDCT scanners provide rapid image acquisition, reducing motion artifact and produce exquisite multiplanar reformatted images.

 US has the inherent limitation of being operator dependent, poor at assessing deep lobe of the parotid gland, and surveying the neck for lymphadenopathy, as well as time consuming relative to the latest generation MDCT scanners.

 MRI should not be used as a primary imaging modality but reserved for special situations, such as assessment of the skull base for perineural spread of tumors. Although MRI provides similar information to CT, it is more susceptible to motion and has longer image acquisition time but has better soft‐tissue delineation.

 PET/CT can also be utilized for initial diagnosis and staging but excels in localizing recurrent disease in postsurgical or radiation fields. Its limitations are specificity, as inflammatory diseases and some benign lesions can mimic malignant neoplasms, and malignant lesions such as adenoid cystic carcinoma may not demonstrate significantly increased uptake of FDG. A major benefit is its ability to perform combined anatomic and functional evaluation of the head and neck as well as upper and lower torso in the same setting. The serial acquisitions are fused to provide a direct anatomic correlate to a focus of radiotracer uptake.

 Newer MRI techniques such as dynamic contrast enhancement, MR sialography, diffusion weighted imaging, MR spectroscopy, and MR microscopy are challenging PET/CT in functional evaluation of salivary gland disease and delineation of benign versus malignant tumors. However, PET/CT with novel tracers may repel this challenge.

 Conventional radionuclide scintigraphic imaging has largely been displaced. However, conventional scintigraphy with 99mTc‐pertechnetate can be useful for the evaluation of masses suspected to be Warthin tumors or oncocytomas, which accumulate the tracer and retain it after washout of the normal gland with acid stimulants. The advent of SPECT/CT in a similar manner to PET/CT may breathe new life into older scintigraphic exams.

 Radiology continues to provide a very significant contribution to clinicians and surgeons in the diagnosis, staging, and post‐therapy follow‐up of disease. Because of the complex anatomy of the head and neck, imaging is even more important in evaluation of diseases affecting this region. The anatomic and functional imaging, as well as the direct fusion of data from these methods, has had a beneficial effect on disease treatment and outcome. A close working relationship is important between radiologists, pathologists, and surgeons to achieve these goals.