Imaging in infections of the head and neck.

Infections of the head and neck vary in their clinical course and outcome because of the diversity of organs and anatomic compartments involved. Imaging plays a central role in delineating the anatomic extent of the disease process, identifying the infection source, and detecting complications. The utility of imaging to differentiate between a solid phlegmonous mass and an abscess cannot be overemphasized. This review briefly describes and pictorially illustrates the typical imaging findings of some important head and neck infections, such as malignant otitis externa, otomastoiditis bacterial and fungal sinusitis, orbital cellulitis, sialadenitis, cervical lymphadenitis, and deep neck space infections.

Differential diagnosis for bilateral abnormalities of the basal ganglia and thalamus.

The basal ganglia and thalamus are paired deep gray matter structures that may be involved by a wide variety of disease entities. The basal ganglia are highly metabolically active and are symmetrically affected in toxic poisoning, metabolic abnormalities, and neurodegeneration with brain iron accumulation. Both the basal ganglia and thalamus may be affected by other systemic or metabolic disease, degenerative disease, and vascular conditions. Focal flavivirus infections, toxoplasmosis, and primary central nervous system lymphoma may also involve both deep gray matter structures. The thalamus is more typically affected alone by focal conditions than by systemic disease. Radiologists may detect bilateral abnormalities of the basal ganglia and thalamus in different acute and chronic clinical situations, and although magnetic resonance (MR) imaging is the modality of choice for evaluation, the correct diagnosis can be made only by taking all relevant clinical and laboratory information into account. The neuroimaging diagnosis is influenced not only by detection of specific MR imaging features such as restricted diffusion and the presence of hemorrhage, but also by detection of abnormalities involving other parts of the brain, especially the cerebral cortex, brainstem, and white matter. Judicious use of confirmatory neuroimaging investigations, especially diffusion-weighted imaging, MR angiography, MR venography, and MR spectroscopy during the same examination, may help improve characterization of these abnormalities and help narrow the differential diagnosis.

Two cases of anomalous origins of left coronary artery with a course between the aortic root and the free standing subpulmonary infundibulum on CT coronary angiography.

Two cases of anomalous origins of the left coronary artery have been demonstrated on a CT coronary angiogram. In one case the left main coronary artery arose from the right aortic sinus of valsalva, separate from the right coronary artery. In the second case there was a single coronary artery arising from the right aortic sinus of valsalva. In both these rare cases, the left main coronary artery traversed between the aortic root and the freestanding subpulmonary infundibulum and then divided into its regular branches. These cases show well, the left main artery actually coursing free of the crista supraventricularis portion of the outlet septum. This is contrary to the commonly used classifications and descriptions, which describe the anomalous coronary artery actually traversing through the outlet septum.