VOL 65 NO 776 AUGUST 1992 The British Journal of Radiology Contents Page t Papen 649 Use of A. K Direct 653 A. B Sublux ' ' %^mm',/ -N ; tiaging 662 K. A ^ sfty$2^ ^ ndT.Kozuka What , " • . of patients not re-e> . * * / 668 Y. 0 - (tf/ty ~~ 7 ¥ >- *' H' Matsumoto and ~ /, > > of metastasis 672 Intracs 7 JjCt^f^f t D-^- - - « The radiology and terminology of cryptogenic organizing pneumonia 674 J. A. A. Haddock and D. M. Hansell The radiological imaging of bronchial atresia 681 D. Kinsella, G. Sissons and M. P. Williams An alternative approach to contrast-detail testing of X-ray image intensifier Systems 686 C. /. Kotre, N. W. Marshall and K. Faulkner Accelerated fast neutron therapy: a pilot study 691 D. J. Husband, R. D. Errington, S. Myint, J. A. H. Linier and H. M. Warenius Low oxygen extraction fraction in tumours measured with the oxygen-15 steady State technique: effect of tissue heterogeneity 697 A. A. Lammertsma and T. Jones Image comparison techniques for use with megavoltage imaging Systems 701 P. M. Evans, J. Q. Gildersleve, E. J. Morton, W. Swindell, R. Coles, M. Ferraro, C. Rawlings, Z. JR. Xiao and J. Dyer Asymptomatic temporal lobe injury after radiotherapy for nasopharyngeal Carcinoma: incidence and determinants 710 S. F. Leung, L, Kreel and S. Y. Tsao Technical notes Anal endosonography: which endoprobe? 715 M, Papachrysostomou, S. D. Pye, S. R. Wild and A. N. Smith Virtual source distances and field geometry independent Output factors for 5-14 MeV electron beams from a Siemens Mevatron M7145 717 J. H. Plane and M. M. Trevor Case reports Gadolinium-DTPA enhanced MRI in neonatal Osteomyelitis of the cervical spine 720 A. Martijn, A. M. van der Vliet, W. M. van Waar de and W. M. C. van Aalderen Patellar metastasis: a rare presentation 722 R. K. Sur, D. P, Singh, M. S. Dhillon, B. D. Gupta, D. Murali and R. Sidhu Renal ultrasonographic appearances at presentation in an infant with Lesch-Nyhan Syndrome 724 C. N. Ludman, C. Dicks-Mireaux and A. J. Saunders Small cell Carcinoma of the prostate 726 7. Sule-Suso and A. M. Brunt Case of the month A rare cause of a common Symptom 729 P. J. Close and P. L. Monks Correspondence Spontaneous disappearance of staghorn calculus L. Sheppard Author's reply D. S. Grant Radiation damage to mouse skin and Oesophagus A. Michalowski Proceedings Proceedings of the British Institute of Radiology The new legislation—friend or foe (after the White Paper and into Europe), 13 June 1991 733 Book reviews Introduction to Radiobiology. M. Tubiana, J. Dutreix and A. Wamber sie 736 The Visible Human Body: An Atlas of Sectional Anatomy. G. Von Hagens, L. J. Romrell, M. H, Ross and K. Tiedemann 736 Easily Missed Fractures and Corner Signs in Radiology. H. O. Riddervold 736 BIR Bulletin facing page 736 © 1992 The British Institute of Radiology. This publication is Copyright under the Berne Convention and the Universal Copyright Convention. All rights reserved, apart from any relaxations permitted under national Copyright laws, no part of this publication rnay be reproduced, siored in a retrieval system or transmitted in any form or by any means without the prior permission of the Copyright owners. Permission is not, however, required to copy abstracts of papers or of articles on condition that a füll reference to the source is shown. Multiple copying of the Contents of the publication without permission is always illegal. Published by The British Institute of Radiology, 36 Portland Place. London WIN 4AT. Origination by BPCC Whitefriars Ltd, Tunbridge Wells, and printed and bound in Great Britain by BPCC Wheatons Ltd, Exeter. ISSN 0007 1285 1992, The British Journal of Radiology, 65, 653-661 Direct and CT measurements of canals and foramina of the skull base By *A. Berus, R. Putz, MD and *M. Schumacher, MD Anatomische Anstalt, Ludwig-Maximilians-Universität Müchen, Pettenkoferstrasse 11, D-8000 München and 'Abteilung Röntgendiagnostik, Sektion Neuroradiologie, Albert-Ludwigs-Universität Freiburg i.Br., D-7800 Freiburg i.Br., Hauptstrasse 5, Germany (Received 9 July 1991 and in revised form 20 November 1991, accepted 14 January 1992) Keywords: Skull base, CT, Foramen, Canal, Fissure Abstract. This investigation is based on measurements of 60 macerated adult European skulls from the Alexander-Ecker Collection at the Anatomy Department of the University of Freiburg. Computer tomographical (CT) and anatomical measurements were compared to assess the accuracy of the CT representation of osseous structures. Nine structures were examined: the optic canal; the superior orbital fissure; the foramen rotundum; the foramen ovale; the foramen spinosum; the foramen Vesaiii (venosum); the carotid canal; the internal auditory canal, and the hypoglossal canal. The results show a good and even excellent correlation if the cranial opening is approximately at a right angle to the scanline. For this reason, the results of the coronal examination of the internal auditory canal are less satisfactory, and the coronal and axial measurements of the hypoglossal canal show only a moderately good correlation. Knowledge of the normal and variant positions of the (0-260 + 1 mm) and a tintack with a millimetre rule canals and foramina of the skull base is important for (±1 mm). radiologists, neurosurgeons and anatomists, because of The CT scans of the skull base were obtained using a the increasingly refined techniques available. Although Siemens Somatom DR-H. Continuous 1 mm sections the effectiveness of computed tomography (CT) in diag- were taken at angles of 10° (axial projection) and 70° nosing bony lesions is uncontested, most of the authors (coronal projection) to the radiographic baseline (RB) describe optimal positioning without mentioning the (Reid's baseline or anthropological baseline). The CT correlation between their Undings and the actual anato• number ränge was viewed at a window width of mical position of the osseous structures referred to at 4000 HE. The exposure factors were 550 mA and the time of writing. CT measurements of the position of 125 kV with a scan speed of 9.6 s. The skulls were the internal auditory porus (Heller et al, 1983), the positioned in plastic on a table and the scanlines were internal auditory canal (Silverstein et al, 1988) and the defined by Topo-scan. Double measurements were foramen Vesaiii (venosum) (Lanzieri et al, 1988) are recorded directly on the monitor using a Joystick. available. Only Silverstein et al (1988), however, have assessed the correlation between CT measurements and those taken from dissections of the temporal bone. Results In the following study, anatomical and CT measure• Optic canal (Figs 1 & 8). Following Lang (1981), we ments, including length, breadth and height of optic divided this canal into three parts: an orbital part (an canals, superior orbital fissure, foramen rotundum, elongated oval on section), a middle part or "optic foramen ovale, foramen spinosum, foramen Vesaiii waist" (Lang & Oehmann, 1976) and an intracranial (venosum), carotid canal, internal auditory canal, and part. The mean angle of the axis of the canal and the hypoglossal canal, and the distances between these sagittal plane (SP) was 39.1°, and the RB was -15.5°. structures, are evaluated. The extent to which anato• This means that the coronal sections met the canal at an mical variations can be assessed by CT has also been angle of 85.5°. investigated. Several variants show asymmetry in the shape of the canal. The so-called keyhole anomaly (Fig. 1) is a result Material and methods of the absence of the floor at the cranial opening (Potter A total of 60 macerated adult European skulls from & Trokel, 1971). This anomaly appears in 3.3% of our the Alexander-Ecker Collection at the Anatomy material. Another variant is the figure-of-eight optic Department of the University of Frei bürg were studied. canal, with a separate canal for the Ophthalmie artery For the direct anatomical measurements we used produced by a spicule of bone uniting the roots of the digital internal callipers (Mitutoyo 526-153/526-163: lesser wing of the sphenoid. This appeared as a dupli- 1.50-7.30 + 0.01 mm), a digital measuring instrument cate cranial opening with lengths of 3.0, 2.5 or 1.6 mm (Mitutoyo 500-110: 0-150 + 0.02 mm), an anthropo- and a thickness of 1.4, 1.7 or 1.5 mm. The lumen metric instrument (Bertis, 1990) of our own construction measured 2.11 x 1.55, 1.76 x 1.00 or 2.50 x 2.00 mm, and Vol. 65, No. 776 653 A. Berlis, R. Putz and M. Schumacher Figure 2. Axial projection of the skull base. 1 = Measuring line Figure 1. Coronal projection of the optic canal of the skull between foramina ovalia; 2 = measuring line between foramina 42/351. A separate passage for the Ophthalmie artery appears spinosa; 3 = carotid canal; 4 = pharyngotympanic tube; 5 = on both sides of the skull. 1 = Right optic canal—it appears to external auditory meatus; 6 = inferior orbital fissure; 7 = be a "keyhole" anomaly, but its "figure-of-eight" character can middle cranial fossa; 8 = foramen Vesaiii and 9 = mandibular be seen at a deeper level; 2 = left optic canal of "keyhole" type fossa. and 3 = foramen ovale. sphenoidal wing posterior to the foramen rotundum. In had an incidence of 2.5% (individual measurements in most cases it is postero-medial, and in a few cases Table I). postero-lateral, to the foramen rotundum. In 25% of Superior orbital fissure. The superior orbital fissure cases we found the foramen on the right side, in 35% on was explored in coronal projection and could be seen in the left side, bilaterally in 15% and completely absent in its entirety (individual measurements in Table II).