An ultra-fast user-steered image segmentation paradigm: live wire on the fly.

We have been developing general user steered image segmentation strategies for routine use in applications involving a large number of data sets. In the past, we have presented three segmentation paradigms: live wire, live lane, and a three-dimensional (3-D) extension of the live-wire method. In this paper, we introduce an ultra-fast live-wire method, referred to as live wire on the fly, for further reducing user's time compared to the basic live-wire method. In live wire, 3-D/four-dimensional (4-D) object boundaries are segmented in a slice-by-slice fashion. To segment a two-dimensional (2-D) boundary, the user initially picks a point on the boundary and all possible minimum-cost paths from this point to all other points in the image are computed via Dijkstra's algorithm. Subsequently, a live wire is displayed in real time from the initial point to any subsequent position taken by the cursor. If the cursor is close to the desired boundary, the live wire snaps on to the boundary. The cursor is then deposited and a new live-wire segment is found next. The entire 2-D boundary is specified via a set of live-wire segments in this fashion. A drawback of this method is that the speed of optimal path computation depends on image size. On modestly powered computers, for images of even modest size, some sluggishness appears in user interaction, which reduces the overall segmentation efficiency. In this work, we solve this problem by exploiting some known properties of graphs to avoid unnecessary minimum-cost path computation during segmentation. In live wire on the fly, when the user selects a point on the boundary the live-wire segment is computed and displayed in real time from the selected point to any subsequent position of the cursor in the image, even for large images and even on low-powered computers. Based on 492 tracing experiments from an actual medical application, we demonstrate that live wire on the fly is 1.3-31 times faster than live wire for actual segmentation for varying image sizes, although the pure computational part alone is found to be about 120 times faster.

[Intrathecal morphine for postoperative pain relief after transvaginal hysterectomy].

We studied the effect of a low-dose intrathecal morphine (0.1 or 0.2 mg) in postoperative pain relief and the incidence of side effects. Two hundred and fifteen patients scheduled for transvaginal hysterectomy were divided into 3 groups according to intrathecal morphine doses: M1 (morphine 0.1 mg N = 75), M2 (morphine 0.2 mg N = 69) and C (control N = 71). A standard mid-line lumbar puncture was performed using a 25-gauze needle in the L3/4 interspace. Preservative-free morphine hydrochloride mixed in hyperbaric tetracaine solution was administered intrathecally. Pain relief was significantly greater for the first 24 hrs in groups M1 and M2 compared with group C. Respiratory depression was not seen in any groups. The incidence of vomiting was about 40% in all groups. We conclude that intrathecal morphine 0.1-0.2 mg is useful for pain relief after transvaginal hysterectomy and accompanies no major side effects.

[A case report of emergency thoracotomy and aortic cross clamp for massive abdominal hemorrhage due to the rupture of a pancreatic pseudocyst].

The authors present a rare case of a 58-year-old female who had cardiac arrest due to massive abdominal hemorrhage because of the rupture of pancreatic pseudocyst during an emergency operation. We succeeded in resuscitation by performing emergency thoracotomy and internal cardiac compression. Thoracic aortic cross clamping was employed to control bleeding, and we could perform the operation. She recovered without any neurological deficits. Thoracic descending aortic cross clamping should be always considered both before and during operation for the control of massive abdominal hemorrhage to avoid circulatory collapse.