Digital subtraction ductography

Abstract

Digftal subtraction techniquesused in the examination of eight patients with salivary and nasolacrimal disease are described. Materials and MethodsThe theory and technology of digital video subtraction imaging has been described in detail [11. Eight consecutive patients referred for evaluation of suspected salivary or nasolacrimal pathology were examined using digital techniques. Our patients were examined using a dedicated Xonics digital DA-20 system. A 9-inch (23-cm) image intensifier (6-inch [1 5-cm] and 4.5-inch [1 1-cm] field sizes also available) is coupled to an Amperex Plumbicon-based television camera. Analog-to-digital conversion is performed with 1 0 bits of resolution, and video images are stored in a 51 2 x 51 2 x 8-bit-deep memory. The system is based on a PDP LSI 1 1/23 computer and a 184 Mbyte disk; image acquisition protocol programming, mask/image reregistration, and video window control are among the available facilities. For digital sialography, a 0 or 00 cannula was inserted into Stensen's duct, and meglumine iothalamate 60% (4-6 ml) was injected by hand. Video images were acquired at 1 frame/sec. The procedure was performed first in thelateral and then in the posteroanterior (PA) projection.Typical exposure values per frame were 90 kVp, 25 mAs. Each projections required a total of 1 0-25 frames per patient examined.For dacryocystography, a 00 cannula was inserted into the punctum of the inferior canaliculus, and 4 ml of meglumine iothalamate was hand-injected. Digital image acquisition was performed in the PA projection at a 1/sec frame rate for a total of five exposures. Technical factors used were 99 kVp and 64 mAs.Image selection, subtraction, and reregistration are performed by the radiologist. Hardcopy images are recorded by standard multiformat camera.Radiation exposure of the lens of the eye was estimated using a standard phantom and an MDH IOI5C x-ray probe for both procedures.

Per Oral Balloon Sialoplasty: Results in the Treatment of Salivary Duct Stenosis

“…Digital subtraction imaging provided superior diagnostic information over conventional sialography [18] and facilitated sialographic intervention [9]. In 2 further cases of balloon dilatation described by Buckenham and Guest [6], a 20-gauge plastic intravenous cannula was introduced as a sheath to secure access to the parotid duct.…”

Aussagekraft der digitalen Dakryozystographie in der Diagnose von Tränenwegserkrankungen

“…Cambell (5) empfahl 1964 eine vergrol3erende Darstellung des untersuchten Tränenwegsystems (Makrodakryozystographie). 1974 fuhrte Lloyd 21die fotografische Subtraktionsdakryozystographie em, die durch andere Autoren (11,23) (14,16,19,20,22,25,29,31,33,35).…”

Digitale Subtraktions-Dakryozystographie (DS-DCG) und Ergebnisbilanz endonasaler Tränenwegschirurgie*

“…Eine Computertomographie mit vorheriger Kontrastmittelffihlung der Trbnenwege hat sich nicht bewährt (5). Die digitale Subtraktionstechnik dagegen bietet trotz verminderter Ortsauflosung den Vorteil einer bildlichen Eliminierung der bei der konventionellen Technik vorhandenen Uberlagerungen des Gesichtsskelettes mit gleich-mal3iger, vom Hintergrund unabhängiger Darstellung auch schwach kontrastierter Strukturen (6,11,20,21) in Verbindung mit einer urn em Mehrfaches geringeren Strahiendosis im Bereich der Augenlinse (6) und reduzierter Untersuchungszeit.…”

“…73 (1994) struktiver Epiphora eine conditio sine qua non dar. Die digitale Subtraktionstechnik bietet den entscheidenden Vorteil einer bildlichen Eliminierung der bei der konventionellen Technik Uberlagernden knochernen Strukturen des Mittelgesichtes, welche sich hãufig nicht von kontrastierten Gangabschnitten unterscheiden lassen oder Belichtungsprobleme verursachen (6,11,20).…”