Large-Scale Point-Cloud Visualization through Localized Textured Surface Reconstruction.

In this paper, we introduce a novel scene representation for the visualization of large-scale point clouds accompanied by a set of high-resolution photographs. Many real-world applications deal with very densely sampled point-cloud data, which are augmented with photographs that often reveal lighting variations and inaccuracies in registration. Consequently, the high-quality representation of the captured data, i.e., both point clouds and photographs together, is a challenging and time-consuming task. We propose a two-phase approach, in which the first (preprocessing) phase generates multiple overlapping surface patches and handles the problem of seamless texture generation locally for each patch. The second phase stitches these patches at render-time to produce a high-quality visualization of the data. As a result of the proposed localization of the global texturing problem, our algorithm is more than an order of magnitude faster than equivalent mesh-based texturing techniques. Furthermore, since our preprocessing phase requires only a minor fraction of the whole data set at once, we provide maximum flexibility when dealing with growing data sets.

Safety and efficacy of Eraser laser enucleation of the prostate: preliminary report.

PURPOSE: We ascertained the safety and efficacy of the 1,318 nm diode Eraser laser (Rolle and Rolle, Salzburg, Austria) for transurethral enucleation of the prostate. This laser has been successfully used to resect lung metastasis. It cuts and coagulates vascular rich tissue safely and effectively. We describe a prospective, randomized trial of Eraser laser prostate enucleation vs bipolar transurethral prostate resection. MATERIALS AND METHODS: A total of 60 patients with lower urinary tract symptoms suggesting bladder outlet obstruction and a mean prostate size of 59.5 ml on transrectal ultrasound were randomized to Eraser laser prostate enucleation or bipolar transurethral prostate resection. Patients were assessed preoperatively, and 1 and 6 months postoperatively. RESULTS: Eraser laser prostate enucleation was equivalent to bipolar transurethral prostate resection in improvement in International Prostate Symptom Score, maximal flow rate and quality of life. Laser enucleation was significantly superior to bipolar transurethral resection for measured blood loss (mean ± SD 116.83 ± 97.02 vs 409.83 ± 148.61 ml), catheter time (mean 32.80 ± 8.74 vs 65.73 ± 13.72 hours) and hospital time (mean 45.13 ± 14.77 vs 91.20 ± 11.76 hours, each p <0.05). Using the validated Clavien-Dindo system there were 3 grade Id and 1 grade II complications. CONCLUSIONS: Eraser laser prostate enucleation and bipolar transurethral prostate resection were equally safe and effective to relieve bladder outflow obstruction and lower urinary tract symptoms. This laser technique has the advantage of less blood loss, and shorter catheter time and hospital stay.

Route visualization using detail lenses.

We present a method designed to address some limitations of typical route map displays of driving directions. The main goal of our system is to generate a printable version of a route map that shows the overview and detail views of the route within a single, consistent visual frame. Our proposed visualization provides a more intuitive spatial context than a simple list of turns. We present a novel multifocus technique to achieve this goal, where the foci are defined by points of interest (POI) along the route. A detail lens that encapsulates the POI at a finer geospatial scale is created for each focus. The lenses are laid out on the map to avoid occlusion with the route and each other, and to optimally utilize the free space around the route. We define a set of layout metrics to evaluate the quality of a lens layout for a given route map visualization. We compare standard lens layout methods to our proposed method and demonstrate the effectiveness of our method in generating aesthetically pleasing layouts. Finally, we perform a user study to evaluate the effectiveness of our layout choices.

Nephron-sparing surgery for renal tumours: acceleration and facilitation of the laparoscopic technique.

OBJECTIVE: Present our surgical technique for and experience with laparoscopic partial nephrectomy (LPN) for renal tumours during warm ischaemia. METHODS: Twenty-five patients underwent LPN during warm ischaemia via a transperitoneal four-trocar approach. Mean tumour size was 26.2+/-7.3mm (range: 11-39 mm). Sixteen tumours were exophytic, 7 endophytic, and 2 central. The renal vessels were secured by an umbilical tape and occluded by a self-made Rumel tourniquet. Tumours were excised with a cold Endo-shear. The interstitial tissue and collecting system was closed using a running suture secured by two resorbable clips. Parenchymal edges were approximated using a running suture over a haemostatic bolster. The threads were secured by non-resorbable clips. During follow-up, renal function was evaluated by determination of serum creatinine, (99m)Tc-mercaptoacetyltriglycine scintigraphy, and parenchymal transit time. RESULTS: Mean ischaemia time was 28.9+/-5.2 min (range: 19-40 min) and the mean blood loss was 177.4+/-285.5 ml (range: 50-1500 ml). No intraoperative complications occurred and no patient needed conversion to open surgery. Surgical margins were negative in all patients. One postoperative surgical-related perirenal haematoma occurred, which was treated conservatively (no transfusions required). None of the patients had a urinary leak. During a mean follow-up of 6.2 mo (range: 1-15 mo), none of the patients had local or port-site recurrence or distant metastasis. Parenchymal transit time was increased in 1 of 10 investigated patients (ischaemia time: 26 min), indicating ischaemic parenchymal damage. CONCLUSION: Our technical refinements for LPN during warm ischaemia have widened indications to more complex tumours. The use of clips rather than knot tying made the procedure easier and faster and allowed completion of the suturing during an acceptable warm ischaemia time. The self-made Rumel tourniquet is safe and efficient for vessel control and occlusion. These improvements increase feasibility so that LPN can be used by more laparoscopic urologic surgeons.

Detection of pelvic lymph node metastases in patients with clinically localized prostate cancer: comparison of [18F]fluorocholine positron emission tomography-computerized tomography and laparoscopic radioisotope guided sentinel lymph node dissection.

PURPOSE: Accurate detection of lymph node metastases in prostate cancer has important implications for prognosis and approach to treatment. We investigated whether preoperative [18F]fluorocholine combined in-line positron emission tomography-computerized tomography and intraoperative laparoscopic radioisotope guided sentinel pelvic lymph node dissection can detect pelvic lymph node metastases in patients with clinically localized prostate cancer as reliably as extended pelvic lymph node dissection. MATERIALS AND METHODS: A total of 20 patients (mean age 63.9 +/- 6.7 years, range 52 to 75) with clinically localized prostate cancer, prostate specific antigen greater than 10 ng/ml, and/or a Gleason score sum of 7 or greater and negative bone scan were enrolled in the study. [18F]fluorocholine combined in-line positron emission tomography-computerized tomography was performed before surgery. Sentinel pelvic lymph node dissection preceded extended pelvic lymph node dissection including the area of the obturator fossa, external iliac artery/vein and internal iliac artery/vein up to the bifurcation of the common iliac artery. Laparoscopic radical prostatectomy was performed afterward. RESULTS: In 10 of the 20 patients (50%) lymph node metastases were detected, and were exclusively found outside the obturator fossa in 62%. These metastases would not have been identified with standard lymph node dissection of the obturator fossa only. [18F]fluorocholine combined in-line positron emission tomography-computerized tomography was true positive in 1, false-positive in 2, false-negative in 9 and true negative in 8 patients. The largest lymph node metastasis not seen with [18F]fluorocholine combined in-line positron emission tomography-computerized tomography was 8 mm. Laparoscopic sentinel guided lymph node dissection revealed lymph node metastases in 8 of 10 patients. In the other 2 patients sentinel lymph node dissection was not conclusive. In 1 patient normal nodal tissue was completely replaced by cancer and, therefore, there was no tracer uptake in the involved pelvic sidewall/node, and the other patient had no tracer activity at all in the involved pelvic sidewall. Extended pelvic lymph node dissection missed 1 lymph node metastasis (2 mm diameter near pudendal artery) which was detected by sentinel pelvic lymph node dissection only. CONCLUSIONS: Extended pelvic lymph node dissection reveals a higher number of lymph node metastases as described for obturator fossa dissection only. [18F]fluorocholine combined in-line positron emission tomography-computerized tomography is not useful in searching for occult lymph node metastases in clinically localized prostate cancer. Sentinel guided pelvic lymph node dissection allows the detection of even small lymph node metastases. The accuracy of sentinel pelvic lymph node dissection is comparable to that of extended pelvic lymph node dissection when the limitations of the method are taken into consideration.

Laparoscopic nephron sparing surgery: evolution in a decade.

OBJECTIVE: To present our experience with laparoscopic nephron sparing surgery (NSS) over a decade. METHODS: Seventy-eight patients underwent NSS since 1994. Two techniques were used-partial nephrectomy without ischemia (group 1) in 29 patients, and with ischemia (group 2) which was in cold or warm ischemia in 24 and 25 patients respectively. The mean tumour size was 1.97 and 2.2 cm in groups 1 and 2 respectively. Renal reconstruction evolved in our hands during this period. We changed many technical details and now we depend more on clips for securing the sutures rather than free hand knotting. RESULTS: The mean operative time was 162 and 216 minutes in groups 1 and 2 respectively. Mean ischemia time for patients with cold and warm ischemia was 44.9 and 33.8 minutes respectively. 3 patients in group 2 were converted to open surgery. Mean blood loss was 254 and 212 ml for group 1 and 2 respectively with two major bleedings in group 2. Minor intra-operative complication occurred in 3 patients, and major and minor postoperative complication in 15 patients. At a mean follow-up of 23.9 and 12.2 months for groups 1 and 2 respectively there was no recurrence. CONCLUSION: Warm and cold ischemia have widened the indications for laparoscopic NSS to more complex tumours and allow renal reconstruction with acceptable complication rate.