We obtained the venograms using the two-dimensional digital subtraction angiography (2D DSA) images and three dimensional rotation venography (3D RV) images and investigated the potential usefulness of the 3D RV compared with venograms of 2D DSA using the newly developed three-dimensional rotation angiography unit with a flat-panel detector (FPD). This study included 26 sides (11 left, 15 right) in 20 cases (4 males and 16 females) who underwent radiographic examination for management of intracranial tumors and vascular diseases between May 2003 and December 2003. Each patient underwent diagnostic angiography performed on a DSA unit with a FPD. In all patients, the 2D DSA images, including anteroposterior view and lateral view of the carotid artery, were obtained in two stereoscopic views. The 3D RV was used to produce volume-rendered images. Two neuroradiologists investigated the venous configuration of 3D RV compared with that of 2D DSA about the relationship of the venous drainage system on the temporal lobe according to Guppy et al.'s classification. Twenty-four sides of the 26 sides enabled the precious visualization on 3D RV images. In investigation of 2D DSA, 9 sides (37.5%) were classified into type A, 13 (54.2%) into type B, two (8.3%) into type C, and no sides into types D, E, and F. In investigation of 3D RV images, 10 sides (41.7%) were classified into type A, 9 (37.5%) into type B, 1 (4.2%) into type C, 2 (8.3%) into type E, and 2 (8.3%) into type F. Seven of 24 sides demonstrated discrepancy in results between 2D DSA and 3D RV. The 3D RV could be performed by setting the adequate delay in between the injection of the contrast material and starting time of third rotation to acquire the opacified images. In Guppy et al.'s classification, the 3D RV images could demonstrate the precious venous drainage including the venous lakes with use of multiple views and variable reconstruction compared with 2D DSA. Our DSA system with FPD could provide good 3D RV images. These images are very useful for the skull-base surgery because we can understand the three-dimensional vascular anatomy preoperatively.

SummaryWe have been engaged in clinical work using DSA, the first in the world, under a joint study agreement with Hitachi Medical Corporation on the use of the Flat Panel Detector FPD since 2001. We are now in the stage where a certain evaluation process has been finished, but the FPD performance study in angiography has just begun, and, therefore, its clinical evaluation results are very few. Therefore, we studied the relativity between clinical images and physical characteristics in order to examine the characteristics of FPD by referencing them to clinical images. We did an evaluation of the clinical images to which their physical characteristics such as granularity, resolution, contrast, etc., are reflected by comparing FPD and I.I. images.

We have been using an X-ray angiography system that incorporates a flat panel detector (FPD) since December 2001. This system is equipped with the scintillator-type FPD PaxScan 4030A from Varian Medical Systems, and for objective comparison of the image intensifier (I.I.) and FPD, the system is constructed so that these detectors can be used alternatively. Using this system and other X-ray angiography systems, visual studies have been conducted on the digital subtraction angiography (DSA) images acquired by FPD and I.I. We have found from the clinical images that the FPD is superior to the I.I. in depiction of fine blood vessels as well as of physical characteristics. Fluoroscopy images acquired by the FPD were not entirely satisfactory, however the improvement made in its performance now permits equal use of the FPD and I.I. systems.

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