B-0323 Apparent diffusion coefficient for evaluating early tumour response to neoadjuvant chemo-radiotherapy in locally advanced cervical cancer: correlation with histopathology. Preliminary results
M. Iacobucci, M. Miccò, A.L. Valentini, B. Gui, A.M. De Gaetano, L. Bonomo | Friday, March 8, 10:30 – 12:00 / Room F1
Purpose: To evaluate diagnostic accuracy of diffusion-weighted magnetic resonance imaging (DWI) in predicting response to neo-adjuvant chemo-radiotherapy (nCRT) in patients with locally advanced cervical carcinoma using apparent diffusion coefficient (ADC). Cervical lesions ADC were correlated with post-surgical histopathology.
Methods and Materials: 24 women (FIGO>IB Bulky) underwent MRI and DWI prior to, after 2 weeks and at the end of nCRT, using 1.5 T scanner. Cervical lesion volume and ADC were measured at each assessment. Radical hysterectomy was performed 4 weeks after MRI. Treatment response was determined based on histopathology and was classified as complete response (CR), residual (RD) or stable disease (SD). Mean ADCs (mADC), ADC increase and volume reduction (VR) rates were compared using histopathology as reference standard
Results: According to histology, 13/24 (54%) had CR, 11/24 (46%) had RD <1 cm. 2 patients presented SD. Before therapy, in the study population mADC was 0.96±0.06×10-³ mm²/s but it was lower in SD (0.76±0.1×10-³ mm²/s). After 2 weeks of nCRT, mADC correlated with tumour response: a) in CR with 23 % percent change (1.20±0.02×10-³ mm²/s vs 0.98±0.06×10-³ mm²/s; P<0.001); b) in RD with 10 % percent change (1.05±0.02×10-³ mm²/s vs 0.93±0.06×10-³ mm²/s; P<0.001). Tumour volume decreased in CR and RD with reduction rate of 48 % and 46 %, respectively. At the end of CRT, no significant differences on ADC between CR and RD (mADC 1.20±0.07×10-³ mm²/s vs 1.17±0.06×10-³ mm²/s; P>1) were observed. All CR had local inflammation at histology.
Conclusion: ADC is early indicator of tumour response in patients with advanced cervical cancer.
B-0297 Non-solid, part-solid or solid? Classification of pulmonary nodules in thoracic CT by radiologists and a computer-aided diagnosis system
C. Jacobs, E.M. van Rikxoort, J.-M. Kuhnigk, E.T. Scholten, P.A. de Jong, C. Schaefer-Prokop, M. Prokop, B. van Ginneken | Friday, March 8, 10:30 – 12:00 / Room D1
Purpose: Classifying pulmonary nodules into solid, part-solid and non-solid is crucial for patient management. A computer algorithm is compared to a radiologist on a large data set obtained from a multi-center lung cancer screening trial.
Methods and Materials: Low-dose chest CT scans (16×0.75mm, 120-140 kVp, 30 mAs) with part-solid, non-solid, and solid nodules with a diameter between 7 and 30 mm were randomly selected from two sites participating in the Dutch-Belgian NELSON lung cancer screening trial. The set contained 137 scans, including 50 part-solid, 50 non-solid and 52 solid nodules. The nodule-type recorded in the screening database was used as a reference standard. An automated classification system for characterization of nodules was designed using morphometric features. The accuracy of the computer algorithm was evaluated in three ways: classifying nodules (1) as solid or subsolid, (2) as solid, part-solid or non-solid, and, (3) for the subsolid lesions only, as part-solid or non-solid. An experienced thoracic radiologist independently performed the same classification.
Results: The accuracy of the automated system to differentiate between solid and subsolid nodules was 0.88, compared to 0.95 for the radiologist. The computer classified the nodules as solid, part-solid or non-solid with an accuracy of 0.72 versus 0.80 for the radiologist. The software reached an accuracy of 0.71 in differentiating part-solid from non-solid nodules, where the radiologist had an accuracy of 0.77.
Conclusion: A novel automated characterization tool for pulmonary nodules shows promising performance and could aid radiologists in selecting the appropriate workup for pulmonary nodules.
A-339 Chairman’s introduction
M. Krokidis, A.A. Hatzidakis | Saturday, March 9, 16:00 – 17:30 / Room N/O
There are some basic IR techniques everybody needs to know before starting to treat biliary diseases. Τhese are Percutaneous Transhepatic Cholangiography (PTC) and Percutaneous Transhepatic Biliary Drainage (PTBD). These basic procedures are essential first for opacification and then for getting access into the biliary tree. After accessing the biliary system, decisions must be made about the need for further interventional procedures. Presence of benign or malignant strictures, stones or other kind of disease are leading us to the necessary actions, such as dilatation, stenting or lithotripsy. Dilatation of stenosed parts of the biliary system is performed after negotiation of the stricture or occlusion with help of high-pressure angioplasty balloons of variant sizes. Balloons of 8-14 mm width can be used alone or two parallel to each other. Stenting is rarely needed in benign biliary disease and usually in cases where multiple dilatations are not responding. Percutaneous lithotripsy with or without cholangioscopic assistance is a wide-used technique for clearance of biliary stones or fragments. Extraction balloons or baskets and special lithotripsy devices are commonly used for impacted or large calculi.
