CT and MR Appearance of Teeth: Analysis of Anatomy and Embryology and Implications for Disease.

Abnormalities of dental development and anatomy may suggest the presence of congenital or acquired anomalies. The detection of abnormalities, therefore, is an important skill for radiologists to achieve. Knowledge of dental embryology and an understanding of the radiologic appearances of teeth at various stages of maturation are required for the appreciation of abnormal dental development. While many tooth abnormalities are well-depicted on dedicated dental radiographs, the first encounter with a dental anomaly may be by a radiologist on a computed tomographic (CT) or magnetic resonance (MR) exam performed for other reasons. This article depicts normal dental anatomy and development, describing the appearance of the neonatal dentition on CT and MRI, the modalities most often encountered by clinical radiologists. The radiology and dental literature are reviewed, and key concepts are illustrated with supplemental cases from our institution. The value of knowledge of dental development is investigated using the analysis of consecutive MR brain examinations. Finally, the anatomical principles are applied to the diagnosis of odontogenic infection on CT. Through analysis of the literature and case data, the contrast of dental pathology with normal anatomy and development facilitates the detection and characterization of both congenital and acquired dental disease.

Clinical and histological spectrum of elastotic changes induced by penicillamine.

A 79-year-old-man with cystinuria requiring long-term penicillamine therapy presented with a 6-month history of itchy annular lesions in both axillae. Clinical examination revealed lesions consisting of crusted keratotic papules coalescing in an annular distribution. Associated findings included generalized skin laxity accentuated on the upper trunk and arms, as well as small yellowish papules on the neck. Histological evaluation revealed short, thick, eosinophilic elastic fibres with nodular protrusions. Transepidermal elimination of abnormal elastic fibres was also evident. We discuss the histological and clinical spectrum of penicillamine-induced elastotic changes and compare these changes to those seen in primary elastotic disorders.