Evaluation of [18F]-choline PET/CT for staging and restaging of prostate cancer

Purpose: To evaluate the accuracy of [18F]-choline (FCH) positron emission tomography/computed tomography (PET/CT) for staging and restaging of prostate cancer. Methods: FCH PET/CT was performed in 111 patients with prostate cancer using 200MBq FCH: 43 patients [mean age 63years; mean prostrate specific antigen (PSA) 11.58μg/l] were examined for initial staging, and 68 patients (mean age 66.4years) were examined for restaging (mean PSA 10.81μg/l). FCH PET/CT results were correlated to histopathology, bone scan, morphology as revealed by magnetic resonance imaging (MRI) and CT, PET/CT follow-up and PSA follow-up after therapy. Results: FCH PET/CT scans at initial staging correctly showed no metastases in 36/38 patients undergoing radical surgery, as confirmed by PSA levels 2μg/

High-pitch coronary CT angiography with third generation dual-source CT: limits of heart rate

To determine the average heart rate (HR) and heart rate variability (HRV) required for diagnostic imaging of the coronary arteries in patients undergoing high-pitch CT-angiography (CTA) with third-generation dual-source CT. Fifty consecutive patients underwent CTA of the thoracic (n=8) and thoracoabdominal (n=42) aorta with third-generation dual-source 192-slice CT with prospective electrocardiography (ECG)-gating at a pitch of 3.2. No β-blockers were administered. Motion artifacts of coronary arteries were graded on a 4-point scale. Average HR and HRV were noted. The average HR was 66±11beats per minute (bpm) (range 45-96bpm); the HRV was 7.3±4.4bpm (range 3-20bpm). Interobserver agreement on grade of image quality for the 642 coronary segments evaluated by both observers was good (κ=0.71). Diagnostic image quality was found for 608 of the 642 segments (95%) in 43 of 50 patients (86%). In 14% of the patients, image quality was nondiagnostic for at least one segment. HR (p=0.001) was significantly higher in patients with at least one non-diagnostic segment compared to those without. There was no significant difference (p>0.05) in HRV between patients with nondiagnostic segments and those with diagnostic images of all segments. All patients with a HR<70bpm had diagnostic image quality in all coronary segments. The effective radiation dose and scan time for the heart were 0.4±0.1mSv and 0.17±0.02s, respectively. Third-generation dual-source 192-slice CT allows for coronary angiography in the prospectively ECG-gated high-pitch mode with diagnostic image quality at HR up to 70bpm. HRV is not significantly related to image quality of coronary CTA

Combining automated attenuation-based tube voltage selection and iterative reconstruction: a liver phantom study

Objectives: To determine the value of combined automated attenuation-based tube-potential selection and iterative reconstructions (IRs) for optimising computed tomography (CT) imaging of hypodense liver lesions. Methods: A liver phantom containing hypodense lesions was imaged by CT with and without automated attenuation-based tube-potential selection (80, 100 and 120kVp). Acquisitions were reconstructed with filtered back projection (FBP) and sinogram-affirmed IR. Image noise and contrast-to-noise ratio (CNR) were measured. Two readers marked lesion localisation and rated confidence, sharpness, noise and image quality on a five-point scale (1 = worst, 5 = best). Results: Image noise was lower (31-52%) and CNR higher (43-102%) on IR than on FBP images at all tube voltages. On 100-kVp and 80-kVp IR images, confidence and sharpness were higher than on 120-kVp FBP images. Scores for image quality score and noise as well as sensitivity for 100-kVp IR were similar or higher than for 120-kVp FBP and lower for 80-kVp IR. Radiation dose was reduced by 26% at 100kVp and 56% at 80kVp. Conclusions: Compared with 120-kVp FBP images, the combination of automated attenuation-based tube-potential selection at 100kVp and IR provides higher image quality and improved sensitivity for detecting hypodense liver lesions in vitro at a dose reduced by 26%. Key Points: • Combining automated tube voltage selection/iterative CT reconstruction improves image quality. • Attenuation values remain stable on IR compared with FBP images. • Lesion detection was highest on 100-kVp IR images

Clinical impact of 18F-choline PET/CT in patients with recurrent prostate cancer

Purpose: To investigate the clinical value of 18F-fluorocholine PET/CT (CH-PET/CT) in treatment decisions in patients with recurrent prostate cancer (rPCA). Methods: The study was a retrospective evaluation of 156 patients with rPCA and CH-PET/CT for restaging. Questionnaires for each examination were sent to the referring physicians 14-64months after examination. Questions included information regarding initial extent of disease, curative first-line treatment, and the treatment plan before and after CH-PET/CT. Additionally, PSA values at diagnosis, after initial treatment, before CH-PET/CT and at the end of follow-up were also obtained from the questionnaires. Results: Mean follow-up was 42months. The mean Gleason score was 6.9 at initial diagnosis. Initial treatment was: radical prostatectomy in 110 patients, radiotherapy in 39, and combined prostatectomy and radiotherapy in 7. Median PSA values before CH-PET/CT and at the end of follow-up were 3.40ng/ml and 0.91ng/ml. PSA levels remained stable, decreased or were below measurable levels in 108 patients. PSA levels increased in 48 patients. In 75 of the 156 patients (48%) the treatment plan was changed due to the CH-PET/CT findings. In 33 patients the therapeutic plan was changed from palliative treatment to treatment with curative intent. In 15 patients treatment was changed from curative to palliative. In 8 patients treatment was changed from curative to another strategy and in 2 patients from one palliative strategy to another. In 17 patients the treatment plan was adapted. Conclusion: CH-PET/CT has an important impact on the therapeutic strategy in patients with rPCA and can help to determine an appropriate treatmen

Randomised trial of oral versus sequential intravenous/oral cephalosporins in children with pyelonephritis

The hypothesis was tested that oral antibiotic treatment in children with acute pyelonephritis and scintigraphy-documented lesions is equally as efficacious as sequential intravenous/oral therapy with respect to the incidence of renal scarring. A randomised multi-centre trial was conducted in 365 children aged 6 months to 16years with bacterial growth in cultures from urine collected by catheter. The children were assigned to receive either oral ceftibuten (9mg/kg once daily) for 14days or intravenous ceftriaxone (50mg/kg once daily) for 3days followed by oral ceftibuten for 11days. Only patients with lesions detected on acute-phase dimercaptosuccinic acid (DMSA) scintigraphy underwent follow-up scintigraphy. Efficacy was evaluated by the rate of renal scarring after 6 months on follow-up scintigraphy. Of 219 children with lesions on acute-phase scintigraphy, 152 completed the study; 80 (72 females, median age 2.2 years) were given ceftibuten and 72 (62 females, median age 1.6years) were given ceftriaxone/ceftibuten. Patients in the intravenous/oral group had significantly higher C-reactive protein (CRP) concentrations at baseline and larger lesion(s) on acute-phase scintigraphy. Follow-up scintigraphy showed renal scarring in 21/80 children treated with ceftibuten and 33/72 with ceftriaxone/ceftibuten (p = 0.01). However, after adjustment for the confounding variables (CRP and size of acute-phase lesion), no significant difference was observed for renal scarring between the two groups (p = 0.2). Renal scarring correlated with the extent of the acute-phase lesion (r = 0.60, p < 0.0001) and the grade of vesico-ureteric reflux (r = 0.31, p = 0.03), and was more frequent in refluxing renal units (p = 0.04). The majority of patients, i.e. 44 in the oral group and 47 in the intravenous/oral group, were managed as out-patients. Side effects were not observed. From this study, we can conclude that once-daily oral ceftibuten for 14days yielded comparable results to sequential ceftriaxone/ceftibuten treatment in children aged 6months to 16years with DMSA-documented acute pyelonephritis and it allowed out-patient management in the majority of these childre

Performance of turbo high-pitch dual-source CT for coronary CT angiography: first ex vivo and patient experience

Objectives: To evaluate image quality, maximal heart rate allowing for diagnostic imaging, and radiation dose of turbo high-pitch dual-source coronary computed tomographic angiography (CCTA). Methods: First, a cardiac motion phantom simulating heart rates (HRs) from 60-90bpm in 5-bpm steps was examined on a third-generation dual-source 192-slice CT (prospective ECG-triggering, pitch 3.2; rotation time, 250ms). Subjective image quality regarding the presence of motion artefacts was interpreted by two readers on a four-point scale (1, excellent; 4, non-diagnostic). Objective image quality was assessed by calculating distortion vectors. Thereafter, 20 consecutive patients (median, 50years) undergoing clinically indicated CCTA were included. Results: In the phantom study, image quality was rated diagnostic up to the HR75 bpm, with object distortion being 1mm or less. Distortion increased above 1mm at HR of 80-90bpm. Patients had a mean HR of 66bpm (47-78bpm). Coronary segments were of diagnostic image quality for all patients with HR up to 73bpm. Average effective radiation dose in patients was 0.6 ± 0.3mSv. Conclusions: Our combined phantom and patient study indicates that CCTA with turbo high-pitch third-generation dual-source 192-slice CT can be performed at HR up to 75bpm while maintaining diagnostic image quality, being associated with an average radiation dose of 0.6mSv. Key points : • CCTA is feasible with the turbo high-pitch mode. • Turbo high-pitch CCTA provides diagnostic image quality up to 73bpm. • The radiation dose of high-pitch CCTA is 0.6mSv on average

Assessment of focal liver lesions in non-cirrhotic liver – expert opinion statement by the Swiss Association for the Study of the Liver and the Swiss Society of Gastroenterology

Focal liver lesions are common, with a prevalence up to 20%. The lesions must be evaluated in context of risk factors associated with malignancy. Risk factors include age >40 years, known current or past malignancy, presence of liver cirrhosis or chronic liver disease (i.e. suspected by elevated liver elastography measurement ≥8 kPa or FIB-4 score ≥1.3), unintentional weight loss, fever or night sweats, newly detected focal liver lesions, documented growth of focal liver lesions, current or past use of androgens (e.g. testosterone, oxymetholone, danazol), increased serum tumour markers (i.e. alpha-fetoprotein, carbohydrate antigen 19-9 [CA19-9], carcinoembryonic antigen [CEA]) and family history of malignancy. In patients without risk factors of malignancy, regional (non-)fatty changes, simple liver cysts and typical haemangiomas can be diagnosed by conventional ultrasound (without contrast). Conventional ultrasound Doppler is recommended to rule out vascular malformations such as portosystemic shunts. In all other cases of focal liver lesions, contrast-enhanced imaging is indicated for differentiation in benign and malignant dignity. Contrast-enhanced ultrasound (CEUS) as a first diagnostic step and contrast-enhanced magnetic resonance imaging (MRI) are accurate tests to diagnose haemangioma and focal nodular hyperplasia. Hepatocellular adenoma is diagnosed by contrast-enhanced MRI and/or histology. “Wash out” on CEUS is highly suspicious for a malignant focal liver lesion. Additional investigations aimed at identifying the primary tumour, as well as staging-computed tomography, MRI and/or histology may be necessary and should be decided on a case-by-case basis. A biopsy of focal liver lesions is indicated in cases of unclear dignity, malignant aspect and focal liver lesions of unclear origin as well as for guiding surgical and oncological management

Automated attenuation-based tube voltage selection for body CTA: Performance evaluation of 192-slice dual-source CT

OBJECTIVE To assess radiation dose and image quality in body CT-angiography (CTA) with automated attenuation-based tube voltage selection (ATVS) on a 192-slice dual-source CT (DSCT). METHODS Forty patients (69.5 ± 9.6 years) who had undergone body CTA with ATVS (ref.kVp 100, ref.mAs 90) using a 2x192-slice CT in single-source mode were retrospectively included. All patients had undergone prior CTA with a 2x128-slice CT and ATVS with identical imaging and contrast media protocols, serving for comparison. Images were reconstructed with iterative reconstruction at similar strength levels. Radiation dose was determined. Image quality was assessed semi-quantitatively (1:excellent, 5:non-diagnostic), aortic attenuation, noise and CNR were determined. RESULTS As compared to 128-slice DSCT, 192-slice DSCT selected tube voltages were lower in 30 patients (75 %), higher in 3 (7.5 %), and similar in 7 patients (17.5 %). CTDIvol was lower with 192-slice DSCT (4.7 ± 1.9 mGy vs. 5.8 ± 2.1 mGy; p < 0.001). Subjective image quality, mean aortic attenuation (342 ± 67HU vs. 268 ± 67HU) and CNR (9.8 ± 2.5 vs. 8.2 ± 2.9) were higher with 192-slice DSCT (all p < 0.01), all datasets being diagnostic. CONCLUSION Our study suggests that ATVS of 192-slice DSCT for body CTA is associated with an improved image quality and further radiation dose reduction of 19 % compared to 128-slice DSCT. KEY POINTS • 192-slice DSCT allows imaging from 70 kVp to 150 kVp at 10 kVp increments. • 192-slice DSCT allows for radiation-dose reduction in body-CTA with ATVS. • Subjective and objective image quality increase compared to 128-slice DSCT

Precision of iodine quantification in hepatic CT: effects of iterative reconstruction with various imaging parameters

OBJECTIVE: The objective of this study was to evaluate the feasibility of using iterative reconstructions in hepatic CT to improve the precision of Hounsfield unit quantification, which is the degree to which repeated measurements under unchanged conditions provide consistent results. MATERIALS AND METHODS: An anthropomorphic liver phantom with iodinated lesions designed to simulate the enhancement of hypervascular tumors during the late hepatic arterial phase was imaged, and images were reconstructed with both filtered back projection (FBP) and iterative reconstructions, such as adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR). This protocol was further expanded into various dose levels, tube voltages, and slice thicknesses to investigate the effect of iterative reconstructions under all these conditions. The iodine concentrations of the lesions were quantified, with their precision calculated in terms of repeatability coefficient. RESULTS: ASIR reduced image noise by approximately 35%, and improved the quantitative precision by approximately 5%, compared with FBP. MBIR reduced noise by more than 65% and improved the precision by approximately 25% compared with the routine protocol. MBIR consistently showed better precision across a thinner slice thickness, lower tube voltage, and larger patient, achieving the target precision level at a dose lower (≥ 40%) than that of FBP. CONCLUSION: ASIR blended with 50% of FBP indicated a moderate gain in quantitative precision compared with FBP but could achieve more with a higher percentage. A higher gain was achieved by MBIR. These findings may be used to reduce the dose required for reliable quantification and may further serve as a basis for protocol optimization in terms of iodine quantification