Lung segment geometry study: simulation of largest possible tumours that fit into bronchopulmonary segments.

BACKGROUND: Segmental resection in stage I non-small cell lung cancer (NSCLC) has been well described and is considered to have similar survival rates as lobectomy but with increased rates of local tumour recurrence due to inadequate parenchymal margins. In consequence, today segmentectomy is only performed when the tumour is smaller than 2 cm. METHODS: Three-dimensional reconstructions from 11 thin-slice CT scans of bronchopulmonary segments were generated, and virtual spherical tumours were placed over the segments, respecting all segmental borders. As a next step, virtual parenchymal safety margins of 2 cm and 3 cm were subtracted and the size of the remaining tumour calculated. RESULTS: The maximum tumour diameters with a 30-mm parenchymal safety margin ranged from 26.1 mm in right-sided segments 7 + 8 to 59.8 mm in the left apical segments 1-3. CONCLUSIONS: Using a three-dimensional reconstruction of lung CT scans, we demonstrated that segmentectomy or resection of segmental groups should be feasible with adequate margins, even for larger tumours in selected cases.

[Virtual organization in the digital age of radiology - principle and solution for radiologic research?]. / Virtuelle Organisation im digitalen Zeitalter der Radiologie - Prinzip und Lösung für die radiologische Forschung?

The research project "VICORA - Virtual Institute for Computer-Assisted Radiology", funded by the German Federal Ministry of Education and Research, was initiated in the year 2000. Its virtual organization brings together physical science, engineering, information technology, clinical radiology and the medical technology industry. In the German radiology research domain VICORA serves as a model for interdisciplinary collaboration for the changing radiology paradigm illustrated by a "radiologycube". The project does not only aim at scientific goals but also considers the infrastructure, components and human resource management within a virtual organization. The common rapid prototyping platform ILAB 4 ensures user-friendly and time-efficient software that assists with the routine radiology work-flow including full DICOM functionality. By offering a new work environment and collaborative culture based on telematics and knowledge exchange in radiology research, VICORA overcomes limitations of traditional research organization.

[Three-dimensional reconstruction of central lung tumors based on CT data]. / Dreidimensionale Rekonstruktion von zentralen Lungentumoren basierend auf CT-Daten : Erste klinische Erfahrungen First clinical experiences.

BACKGROUND: CT scanning of the lungs is the standard procedure for preoperative evaluation of central lung tumors. The extent of the tumor and infiltration of central lung structures or lung segments are decisive parameters to clarify whether surgery is possible and the extent of resection. With computer-assisted methods for the segmentation of anatomical structures based on CT data (Fraunhofer MeVis, Bremen) an enhanced, three-dimensional selective visualization is now possible. PATIENTS AND METHODS: From August 2007 through June 2009, 22 patients with central lung tumors were treated at the department of thoracic surgery, University of Schleswig-Holstein, campus Lübeck. There were 15 males and 7 females with a mean age of 60.2 years (range 41-74 years), 18 patients had a long history of smoking, while 4 patients had never smoked. Of the patients 20 had a primary lung carcinoma, 1 patient had local recurrent lung cancer after lobectomy and 1 patient had a central lung metastasis from a non-pulmonary primary carcinoma. A multi-slice detector computer tomogram (MSDCT) scan was performed in all cases. All data were three-dimensionally reconstructed and visualized using special computer-aided software (Fraunhofer MeVis, Bremen). Pulmonary lung function tests, computed postoperative lung volume, bronchoscopic findings, general condition of the patients and the three-dimensionally reconstructed CT data were used for an individual risk analysis and surgical planning. RESULTS: According to the risk analysis 14 out of the 22 patients were surgically treated, 7 patients were staged as functionally inoperable and 1 as technically inoperable. A pneumonectomy was performed in 5 cases, a lobectomy/bilobectomy in 4 cases, an extended lobectomy in 3 cases and 1 case each of a wedge resection and a sleeve resection. Of the 14 patients 2 were classified as stage Ia/b, 7 patients as stage IIa/b and 5 patients as stage IIIa. The median length of time spent in hospital was 8.5±33 days and the mortality rate was 0%. The three-dimensional visualization of the tumor and its anatomical relationship to central pulmonary vessels and the airway system was feasible in all cases. The three-dimensional reconstruction was confirmed in all cases by surgical exploration. CONCLUSION: Three-dimensional reconstruction of CT scan data is a new and promising method for preoperative presentation and risk analysis of central lung tumors. The three-dimensional visualization with anatomical reformatting and color-coded segmentation enables the surgeon to make a more precise strategic approach for central lung tumors.

Importance of calibration for diameter and area determination by intravascular ultrasound.

BACKGROUND: Intravascular ultrasound (IVUS) permits quantitative assessment of the lumen diameter and area of coronary arteries. The experimental study was performed to evaluate the accuracy of diameter and area measurements. METHODS AND RESULTS: Lumen quantitation (lumen diameter D and cross-sectional area A) in lucite tubes (lumen diameter 2.5 to 5.7 mm, Plexiglas) was performed using a mechanical IVUS system (HP console, 3.5 F catheter, Boston Scientific, 30 MHz). The influence of fluid type (blood, water and saline solution), fluid temperature (20 degrees C/37 degrees C), catheter to catheter variation, gain setting and ultrasound frequency (12, 20 and 30 MHz) was determined. In blood at 20 degrees C there was a constant deviation of the measured diameter from the true luminal diameter of -0.29 +/- -0.04 mm (p < 0.06). In water and saline solution at 20 degrees C the mean deviation from true diameter was -0.21 +/- -0.06 mm (p < 0.06). At 37 degrees C, the deviation in blood was greater than at 20 degrees (-0.34 +/- -0.02 mm) which is > 10% in a 3 mm tube (p < 0.06). Three of the ten catheters tested in water at 20 degrees C underestimated true diameter by more than -0.3 mm. The deviation from true diameter (5 mm tube) with varying gain settings was -0.14 mm to -0.23 mm compared to -0.19 mm at standard settings (p > 0.288). At 12 MHz diameter measured was over-estimated. The error in absolute area estimation increased with increasing diameter tested in blood at 37 degrees C (-1.21 to -2.72 mm2), whereas the relative error ([Measured Area-True Area]/True Area x 100 [%]) was more striking at smaller diameters (up to -25% in the 2.5 mm tube). CONCLUSION: Luminal diameters and areas are underestimated by this particular IVUS system. When IVUS imaging and measurements are made during coronary interventions this error should be taken into account with regard to appropriate sizing of the device and the assessment of the postprocedure result. Because systematic errors might also occur in other IVUS system (not tested in this study), it is advisable to ensure that each system is validated prior to clinical use, especially when exact measurements are required.