Effects of radiation dose reduction on diagnostic performance of 3rd generation Dual Source CT pulmonary angiography.

PURPOSE: To evaluate the effects of radiation dose reduction on diagnostic accuracy and image quality of pulmonary angiography CT (CTPA) in adults with suspected pulmonary embolism (PE). MATERIAL & METHODS: 52 consecutive patients received CTPA for suspected PE. Realistic low-Dose CT simulations were generated using an offline software (ReconCT, Siemens Healthineers, Forchheim, Germany), as either filter back projections (FBP) or iterative reconstruction as ADMIRE (strength 3 or 5) with 25 %, 50 % and 75 % of the original dose. To assess image quality (overall image quality, noise, artifacts, and sharpness) and diagnostic confidence, a five-point scale was used. Patient-based and segment-based diagnostic accuracy was calculated for Low-dose computed tomography (LDCT)-reconstruction with original dose CTPA as a standard of reference. Furthermore, effective radiation doses were calculated using a commercially available dose management platform (Radimetrics, Bayer HealthCare, Leverkusen, Germany). RESULTS: Among 52 patients, a total of 15 patients (28.8 %) had acute pulmonary artery embolism. The median dose-length product and effective dose for all 52 scans were 291.1 ±â€¯210.1 mGy⋅cm and 5.8 ±â€¯3.4 mSv. Overall subjective image quality was highest for ADMIRE 5 with 75 % and lowest for FBP with 25 % of the original dose (median [interquartile range]:5 [5] vs. 3 [2-3], p < 0.001. Patient-based diagnostic accuracy was perfect for all iteratively reconstructed data sets (ADMIRE 3 and 5) (sensitivity: 100 %, negative predictive value [NPV]: 100 %). LDCT data sets with FBP had perfect diagnostic accuracy at 50 % and 75 % of the original dose, which however decreased at 25 % of the original dose (sensitivity: 93 %; [NPV]: 97 %). Segment-based diagnostic accuracy was high for ADMIRE 3 and 5 down to 25 % dose reduction (sensitivity: 90.4 % specificity: 99.5 %) and lowest for FBP with 25 % dose reduction (sensitivity: 84.6 %, specificity: 98.9 %). Inter-class correlation regarding the detection of PE was almost perfect at all doses and recons (ICC: 96.1-1.0). Thus, accurate diagnosis for PE was possible for ADMIRE 3 and 5 datasets with 25 % of the original dose (1.45 mSv) and for FBP with 50 % of the original dose (2.9 mSv). CONCLUSION: Our findings indicate that radiation dose reduction down to 25 % (1.45 mSv) of the original data via iterative reconstruction algorithms on a 3rd generation Dual Source CT (DSCT) scanner maintained the diagnostic accuracy and image quality for the assessment of PE in CTPA.

Diagnostic Performance of Different Simulated Low-Dose Levels in Patients with Suspected Cervical Abscess Using a Third-Generation Dual-Source CT Scanner.

The aim of this study was to investigate the effects of dose reduction on diagnostic accuracy and image quality of cervical computed tomography (CT) in patients with suspected cervical abscess. Forty-eight patients (mean age 45.5 years) received a CT for suspected cervical abscess. Low-dose CT (LDCT) datasets with 25%, 50%, and 75% of the original dose were generated with a realistic simulation. The image data were reconstructed with filtered back projection (FBP) and with advanced modeled iterative reconstruction (ADMIRE) (strengths 3 and 5). A five-point Likert scale was used to assess subjective image quality and diagnostic confidence. The signal-to-noise ratio (SNR) of the sternocleidomastoid muscle and submandibular gland and the contrast-to-noise ratio (CNR) of the sternocleidomastoid muscle and submandibular glandular fat were calculated to assess the objective image quality. Diagnostic accuracy was calculated for LDCT using the original dose as the reference standard. The prevalence of cervical abscesses was high (72.9%) in the cohort; the mean effective dose for all 48 scans was 1.8 ± 0.8 mSv. Sternocleidomastoid and submandibular SNR and sternocleidomastoid muscle fat and submandibular gland fat CNR increased with higher doses and were significantly higher for ADMIRE compared to FBP, with the best results in ADMIRE 5 (all p < 0.001). Subjective image quality was highest for ADMIRE 5 at 75% and lowest for FBP at 25% of the original dose (p < 0.001). Diagnostic confidence was highest for ADMIRE 5 at 75% and lowest for FBP at 25% (p < 0.001). Patient-based diagnostic accuracy was high for all LDCT datasets, down to 25% for ADMIRE 3 and 5 (sensitivity: 100%; specificity: 100%) and lower for FBP at 25% dose reduction (sensitivity: 88.6-94.3%; specificity: 92.3-100%). The use of a modern dual-source CT of the third generation and iterative reconstruction allows a reduction in the radiation dose to 25% (0.5 mSv) of the original dose with the same diagnostic accuracy for the assessment of neck abscesses.

The Belgian Virtual Tumorbank: A Tool for Translational Cancer Research.

Background: Biobanks play a critical role in cancer research by providing high quality biological samples for research. However, the availability of tumor samples in single research institutions is often limited, especially for rare cancers. In order to facilitate the search for samples scattered among different Belgian institutions, a nationwide virtual tumorbank project was launched and is operational since February 2012. The Belgian Virtual Tumorbank (BVT) network encompasses the tumor biobanks from eleven Belgian university hospitals that collect and store residual human tumor samples locally and is coordinated by the Belgian Cancer Registry. Materials and Methods: A web application was developed and consists of two modules. The registration module (BVTr) centralizes the tumor sample data from the local partner biobanks. The catalog module (BVTc) allows researchers to trace the tumor samples in the 11 tumor biobanks. The BVTc contains patient, medical and technical data, but excludes identifying information to ensure privacy of individuals. Automatic and manual controls guarantee high quality data on the samples requested by scientists for research purposes in oncology. A major advantage of the BVT network is that the available data can be linked to the data of the Belgian Cancer Registry for quality control purposes. Results: Currently, more than 92,000 registrations are available in the catalog. Twenty-seven percent of the residual primary tumor samples originate from breast tissue, but also less frequent localisations such as head and neck (4%), male genital organs (1.7%), and urinary tract (1%) are available. In addition to the residual tumor tissue samples, also other available material can be stored and registered by the local biobanks. The most common type is corresponding normal tissue (19%).Other frequently available materials are plasma, blood, serum, DNA, and buffy coat. Even PBMCs, RNA, cytology, and urine are available in some cases. Discussion and Conclusion: The BVT catalog is a valuable source of information for oncology research and the ultimate goal is to promote multidisciplinary cancer research (i.e., pathogenesis, disease prediction, prevention, diagnosis, treatment, and prognosis) for the benefit of all cancer patients.