Contrast-enhanced Reformatted MR Images for Preoperative Assessment of the Bridging Veins of the Skull Base.

Magnetic resonance (MR) venography and computed tomographic (CT) venography are suited for displaying the convexity veins that drain the medial and lateral surfaces of the brain hemispheres. However, such is not the case for the bridging veins of the skull base. Technical factors prevent contrast material-enhanced MR or CT images obtained in standard axial, coronal, and sagittal planes from fully displaying the curved pathways of these clinically important venous structures. This limitation can be overcome by using a reconstruction technique that depicts these venous structures and their interconnections. Curved and multiplanar reformatted images that distill the important venous features often require knowledgeable manipulation of source images by an operator who is familiar with numerous venous variants and their surgical implications. The normal anatomy of the draining veins is detailed-anatomy that radiologists must master before they can show the surgeon the important venous anatomy that is often missing at standard imaging; this information will foster better communication between radiologists and their surgical colleagues. As a practical matter, the skull base veins are arbitrarily subdivided into those that are at greatest risk with the pterional approach and the subtemporal approach, respectively. These approaches can be expanded to define connections between the superficial venous system and the other valveless venous networks that drain the deep portions of the cerebral hemisphere, the scalp, face, muscles of the neck, diploë of the skull, and meninges. As radiologists gain experience, their image interpretations should mature beyond simple analysis of the primary hemodynamic changes induced by intraoperative sacrifice or injury.

Bone invasion by adenoid cystic carcinoma of the lacrimal gland: preoperative imaging assessment and surgical considerations.

PURPOSE: To identify the incidence of radiologically and histologically documented bony invasion of the lacrimal gland fossa by adenoid cystic carcinoma. PATIENTS AND METHODS: The authors reviewed the records of all 18 patients with lacrimal gland adenoid cystic carcinoma surgically treated at their institution from 1997 to 2009 for imaging findings (blinded review) and histologic findings on evaluation of the lacrimal gland fossa. Preoperative CT and/or MRI findings were available for 17 patients. RESULTS: The 8 men and 10 women ranged in age from 9 to 69 years. American Joint Committee on Cancer tumor stages after preoperative imaging were as follows: T1N0M0, 2 patients; T2N0M0, 5 patients; T3aN0M0, 2 patients; T3bN0M0, 5 patients; T3bN0M1, 2 patients; T4bN0M0, one patient; and TxN0M0, one patient. Preoperative imaging suggested bony involvement of the lacrimal gland fossa in 13 patients (76.5%); this was histologically confirmed in 11 of the 13. Preoperative imaging suggested no bone involvement in 4 patients, 3 of whom had bone involvement by histology. Overall, 14 of 17 histologically evaluable cases (82.3%) had invasion of the lacrimal gland fossa. Histologic findings of bone/periosteal involvement led to upstaging of 3 tumors. Metastases developed in 8 of 18 patients and trended with basaloid histology (p = 0.066). CONCLUSIONS: Adenoid cystic carcinoma of the lacrimal gland is associated with bone invasion in essentially all but the smallest of tumors (T1). This high rate of bone involvement may warrant addressing the bony walls during surgery for adenoid cystic carcinoma of the lacrimal gland.