Motivation: We propose a new model-based technique for summarizing high-density oligonucleotide array data at probe level for Affymetrix GeneChips. The new summarization method is based on a factor ...analysis model for which a Bayesian maximum a posteriori method optimizes the model parameters under the assumption of Gaussian measurement noise. Thereafter, the RNA concentration is estimated from the model. In contrast to previous methods our new method called ‘Factor Analysis for Robust Microarray Summarization (FARMS)’ supplies both P-values indicating interesting information and signal intensity values. Results: We compare FARMS on Affymetrix's spike-in and Gene Logic's dilution data to established algorithms like Affymetrix Microarray Suite (MAS) 5.0, Model Based Expression Index (MBEI), Robust Multi-array Average (RMA). Further, we compared FARMS with 43 other methods via the ‘Affycomp II’ competition. The experimental results show that FARMS with default parameters outperforms previous methods if both sensitivity and specificity are simultaneously considered by the area under the receiver operating curve (AUC). We measured two quantities through the AUC: correctly detected expression changes versus wrongly detected (fold change) and correctly detected significantly different expressed genes in two sets of arrays versus wrongly detected (P-value). Furthermore FARMS is computationally less expensive then RMA, MAS and MBEI. Availability: The FARMS R package is available from Contact:hochreit@bioinf.jku.at Supplementary information:
To evaluate if MRI/ultrasound fusion based targeted biopsy (FBx) leads to a reduced rate of change in Gleason score (GS) compared to prostatectomy specimen.
The histopathological findings of the ...biopsy of the prostate and the radical prostatectomy (RP) specimen of 210 patients who were referred to our hospital between 2012 and 2017 were compared retrospectively in this study. One hundred and five patients who underwent FBx combined with ultrasound-guided 12-core biopsy of the prostate (SBx) were matched with 105 patients who underwent SBx only. This study evaluated the rate of up- or downgrading in the RP specimen in both groups and compared the results via matched pair analysis.
Concordance in Gleason grade group (GGG) was found in 52/105 patients (49.5%) in SBx and in 49/105 patients (46.7%) with FBx (p = 0.679). The rate of downgrading was statistically significant (p = 0.014) and was higher in the FBx group (14/105 patients, 13.3%) than in the SBx group (4/105 patients, 3.8%). A higher rate of upgrading was seen in SBx (49/105 patients; 46.7%) compared to FBx (42/105 patients; 40%), with no statistical significance (p = 0.331). The change in GGG from biopsy to final pathology in patients with GGG 1 and 2 at biopsy level was not statistically significant (p = 0.168).
FBx does not decrease the rate of upgrading between biopsy and final pathology in RP specimens. Our results indicate that FBx tends to overestimate the final GGG compared to SBx.
Motorsport karting has developed into a professional international competition. Kart racing poses a unique set of physiologic challenges for athletes who compete in this sport. Until today no major ...study has evaluated the physical and cardiac challenge in professional kart racing.
The aim for this study was to measure and analyze heart rate and cardiac rhythm by a mobile, smartphone based ECG (s-patch) on professional kart-race-drivers during actual karting races through annual seasons to test the hypotheses that high g-force and stress could trigger cardiac arrhythmia.
ECG-data from kart-drivers were acquired during local races, the ADAC Kart-Masters (KZ2), the German Kart Championship (DSKC) and the European Championship Senior CIK-FIA-Serie and analyzed in this observational study. In total, free practice, qualifying practice and 32 races were assessed during the kart season 2019. Data were interpreted by two independent experienced physicians.
The average heart rate (HR) during a selected German Kart Championship (DSKC) race in Genk (Belgium) was 169 beats min-1. The longest R-R interval was 0.72 sec. The average HR during a selected European Championship CIK-FIA-race in Lonato (Italy) was 160 beats min-1. The longest R-R interval was 0.74 sec. The average HR during a selected ADAC Kart-Masters (KZ2) races in Wackersdorf (Germany) was 147 beats min-1. The longest R-R interval was 0.86 sec. In total 32 races could be recorded successful. No couplets or bigeminy cycles were detected. In one other kart racer a supraventricular extrasystole and a ventricular extrasystole was detected. Interestingly, kart-drivers were found to have sinustachycardia throughout the races most likely triggered by emotional and physiological stress during speeding.
Professional kart racing drivers had sinustachycardia with heart rates up to 193 beats min-1 during races. This is most likely attributed to a considerably high emotional and physiological stress affecting the cardiovascular system. Episodes of tachycardia positively correlated with mean speed. In the warm-up lap the heart rate was significantly lower in comparison to the race, suggesting that faster driving speed would induce greater cardiovascular stress to professional drivers during actual races. The experimental results showed that the proposed S-patch system provided a good ECG signal quality with accurate measurements even during the kart race and could detect the ECG features of the race in real time. The cardiac interpretation software performs well and is a useful tool to assist clinicians.
Ultrasound is often the first imaging modality used in the diagnosis of abdominal vascular as well as parenchymal organ pathologies. Contrast-enhanced ultrasound (CEUS) enables the dynamic assessment ...and quantification of microvascularisation up to capillary perfusion. Current clinical applications of CEUS are mainly in detection and characterization of lesions, particularly benign and malignant hepatic and renal lesions, based on differences between lesion and organ perfusion. Multifrequency high-resolution transducers are being increasingly used, including intra-operatively. Dynamic 3D techniques and ultrasound image fusion with CT or MRI may assist the diagnosis and therapy control after interventional procedures. Our own studies have demonstrated the excellent diagnostic performance of CEUS with perfusion-analysis in the characterization of hepatic and renal lesions as well as the assessment of tissue transplant macro- and microvascularisation. CEUS opens up new possibilities in the characterization of the microvasculature with perfusion analysis, even during the course of interventions, thereby providing new possibilities for modified therapeutic strategies. In this review, the different new ultrasound techniques with their potential applications are described and illustrated.
Objective
To investigate the usefulness of contrast-enhanced ultrasound (CEUS) in the evaluation of renal masses.
Methods
This study included 255 patients with renal masses. Ages ranged from 18–86 ...years. CEUS was used for determining malignancy or benignancy and findings were correlated with the histopathological outcome. Out of 255 lesions, 212 lesions were malignant (83.1%) and 43 were benign (16.9%). Diagnostic accuracy was tested using the histopathological diagnosis as the gold standard.
Results
CEUS showed a sensitivity of 99.1% 95% confidence interval (CI): 96.7%, 99.9%, a specificity of 80.5% (CI: 65.1%, 91.2%), a positive predictive value of 96.4% (CI: 93.0%, 98.4%) and a negative predictive value of 94.3% (CI: 80.8%, 99.3%). Kappa for diagnostic accuracy was κ = 0.85 (CI: 0.75, 0.94). Of 212 malignant lesions, 200 renal cell carcinomas and 12 other malignant lesions were diagnosed. Out of 43 benign lesions, 10 angiomyolipomas, 3 oncocytomas, 8 renal cysts and 22 other benign lesions were diagnosed.
Conclusion
CEUS is an useful method to differentiate between malignant and benignant renal lesions. To date, to our knowledge, this is the largest study in Europe for the evaluation of renal lesions using CEUS with a histopathological validation.
Key Points
• CEUS helps clinicians detect and characterise unclear solid and cystic renal lesions
• CEUS shows a high diagnostic accuracy in the characterization of these lesions
• Proper surgical treatment or follow-up can be given with better diagnostic confidence
Vascular complications in renal transplant patients are a well-known issue in post transplant patient care. If malfunctioning of the renal transplant is suspected to be caused by vascular ...complications an early diagnosis and therapy is required to maintain the renal transplant. Computed tomography (CT), digital substraction angiography (DSA) and radioisotope renography are the gold standard imaging modalities to diagnose vascular complications.
To analyse the sensitivity and specificity of contrast-enhanced ultrasound (CEUS) in comparison to the standard imaging modalities CT, DSA and radioisotope renography in the diagnosis of vascular complications in renal transplant patients.
A total of 33 renal transplant recipients with elevated kidney function parameters with initial diagnostic imaging between 2006 and 2017 were included in the study. The imaging studies and clinical data were analysed retrospectively. The diagnostic accuracy of CEUS was compared to CT, DSA and renal scintigraphy respectively which are classified as gold standard for diagnosis of vascular complications in renal transplant patients. Out of 23 patients 15 patients showed vascular complications in CT, DSA or radioisotope renography and in 15 out of 15 patients CEUS detected the vascular complication.
CEUS showed a sensitivity of 100%, a specificity of 66.7%, a positive predictive value (PPV) of 71.4%, and a negative predictive value (NPV) of 100%.
CEUS is a non-nephrotoxic and safe method for the initial imaging of vascular complications in renal transplant recipients. Compared to the gold standard imaging modalities CT, DSA and radioisotope renography CEUS shows a high sensitivity and NPV in detecting vascular complications. In cases with suspected stenosis of the transplant renal artery additional DSA might be needed.
Focal therapy (FT) of the prostate for low risk prostate cancer (PCa) is an alternative to traditional definite treatment options like external beam radiotherapy or radical prostatectomy. However, ...follow up after FT is still challenging and is subject to current studies. Significance of imaging after FT such as multiparametric MRI (mpMRI) is currently not well established. In this study, we aimed to evaluate the efficacy of alternative imaging during the follow up of low risk PCa treated with focal HIFU therapy using CEUS and image fusion.
Retrospective single arm study in patients with uni- or bilateral, low or intermediate risk prostate cancer treated with HIFU at our institution between October 2016 and January 2018. CEUS in combination with image fusion using an axial T2-weighted MRI sequence was performed during follow up 3, 6, 9 and 12 months after the therapy.
4 consecutive patients with Gleason score (GS) 6 and 4 patients with GS 7a prostate cancer were included in the study. Hemiablation was performed in 7 patients with unilateral tumor. One patient underwent whole gland treatment due to histological proven bilateral PCa. Mean patient age at time of therapy was 70.3 (54-83) years and mean Prostate-specific antigen (PSA) level prior treatment was 7.8 ng/ml (2.1-14.4), after 3 months mean PSA level was 3.9 ng/ml (0.1-7.2), after 6 months 3.5 ng/ml (0.2-6.0), after 9 months 3.1 ng/ml (0.2-6.8) and 3.3 ng/ml (0.2-6.1) after 12 months. CEUS showed no signs of microvascularisation after 3, 6, 9 and 12 months in the ablated zone. 3 months posttreatment the necrotic tissue was still visible in the B-mode scan, although with no signs of vascularization performing CEUS. After 6 months the ablated side of the prostate was almost completely atrophic. And after 9 months the necrotic tissue was completely resolved. Between 9 and 12 months no changes in microvascularisation and perfusion could be shown.
MpMRI/CEUS image fusion is a cost-effective and feasible technique to monitor the perfusion of the ablation zone after focal therapy of the prostate.
To assess the diagnostic performance of multislice computed tomography (MS-CT) in the classification of atypical or complex cystic renal masses using the Bosniak system in comparison to ...contrast-enhanced ultrasound (CEUS) and, in unclear cases, to the surgery findings.Thirty-two consecutive patients (14 women, 18 men; age range 39-72 years) with 37 atypical or complex cystic renal masses at MS-CT underwent conventional ultrasound (US) and CEUS. CEUS employed a low-MI technique using 1.6-2.4 ml SonoVue (Bracco, Italy) i.v. and a 2-4 MHz multifrequency transducer (Siemens, Sequoia, Acuson). Fourteen masses were resected, the remaining 23 lesions were followed up for periods ranging from 3 months to 2 years. Images and digital cine clips of all lesions were evaluated by blinded readers. On the basis of MS-CT appearance the lesions were assigned to the Bosniak classification. Similar criteria modified for US imaging were used to score atypical cysts at CEUS. In the Bosniak classification at MS-CT the lesions were scored as category II (n=15), IIF (n=7), III (n=8) and IV (n=7). At CEUS, masses were classified as Bosniak classification II (n=8), IIF (n=12), III (n=8) or IV (n=9). All type IV and 6/8 type III and 1/8 type IIF lesions were removed surgically. All category IV and 3/8 category III lesions of the surgical group were malignant, the one type IIF lesion was benign. All class II and IIF cysts except one were stable after a follow-up period ranging from 3 months to 2 years. In 7/37 lesions (19%) the MS-CT and CEUS scores were different, while in 30/37 (81%) they were equivalent. CEUS depicted more thin septa than MS-CT, or upgraded wall thickness, resulting in a Bosniak score upgrade from category II to IIF in 5 lesions. Two cystic renal masses could not be clearly assigned by MS-CT but were considered malignant due to the additional information from CEUS, which was confirmed by surgical removal (small cystic renal cancer).CEUS with SonoVue allows an early evaluation of atypical or complex cystic renal masses. It is an additional examination to MS-CT. Due to the dynamic examination, additional information about perfusion of the cystic septa or cystic renal cancer can be gained.
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