Purpose
To evaluate whether single-phase dual-energy-CT-based attenuation measurements can reliably differentiate lipid-rich adrenal adenomas from malignant adrenal lesions.
Materials and methods
We ...retrospectively identified 51 patients with adrenal masses who had undergone contrast-enhanced dual-energy-CT (140/100 or 140/80 kVp). Virtual non-contrast and colour-coded iodine images were generated, allowing for measurement of pre- and post-contrast density on a single-phase acquisition. Adrenal adenoma was diagnosed if density on virtual non-contrast images was ≤10 HU. Clinical follow-up, true non-contrast CT, PET/CT, in- and opposed-phase MRI, and histopathology served as the standard of reference.
Results
Based on the standard of reference, 46/57 (80.7 %) adrenal masses were characterised as adenomas or other benign lesions; 9 malignant lesions were detected. Based on a cutoff value of 10 HU, virtual non-contrast images allowed for correct identification of adrenal adenomas in 33 of 46 (71 %), whereas 13/46 (28 %) adrenal adenomas were lipid poor with a density ≥10 HU. Based on the threshold of 10 HU on the virtual non-contrast images, the sensitivity, specificity, and accuracy for detection of benign adrenal lesions was 73 %, 100 %, and 81 % respectively.
Conclusion
Virtual non-contrast images derived from dual-energy-CT allow for accurate characterisation of lipid-rich adrenal adenomas and can help to avoid additional follow-up imaging.
Key Points
•
Adrenal adenomas are a common lesion of the adrenal glands
.
•
Differentiation of benign adrenal adenomas from malignant adrenal lesions is important
.
•
Dual-energy based virtual non-contrast images help to evaluate patients with adrenal adenomas
.
Abstract Carotid duplex ultrasound is the standard of care for the initial diagnosis of carotid artery bifurcation diseases. But in difficult examinations, carotid abnormalities are commonly ...encountered and may represent a diagnostic challenge in patients with clinical symptoms as well as in the follow up after carotid endarterectomy or carotid artery stenting. Contrast enhanced ultrasound (CEUS) with low mechanical index (low MI) is a promising new method in the diagnosis and follow up of pathological carotid diseases. Unlike most contrast agents used for magnetic resonance imaging or computed tomography, the microbubbles used in CEUS with SonoVue® remain within the vascular space and hence can be used to study vascular disease. In addition to improving current carotid structural scans, CEUS has potential to improve or add extra information on carotid arterial diseases. This review describes the current carotid duplex ultrasound examination and compares the pathological findings with CEUS.
Objectives
To assess the benefit of quantitative computed tomography (CT) perfusion for differentiating acute tubular necrosis (ATN) and acute rejection (AR) in kidney allografts.
Methods
Twenty-two ...patients with acute kidney allograft dysfunction caused by either AR (
n
= 6) or ATN (
n
= 16) were retrospectively included in the study. All patients initially underwent a multiphase CT angiography (CTA) protocol (12 phases, one phase every 3.5 s) covering the whole graft to exclude acute postoperative complications. Multiphase CT dataset and dedicated software were used to calculate renal blood flow. Renal biopsy or clinical course of disease served as the standard of reference. Mean effective radiation dose and mean amount of contrast media were calculated.
Results
Renal blood flow values were significantly lower (
P
= 0.001) in allografts undergoing AR (48.3 ± 21 ml/100 ml/min) compared with those with ATN (77.5 ± 21 ml/100 ml/min). No significant difference (
P
= 0.71) was observed regarding creatinine level with 5.65 ± 3.1 mg/dl in AR and 5.3 ± 1.9 mg/dl in ATN. The mean effective radiation dose of the CT perfusion protocol was 13.6 ± 5.2 mSv; the mean amount of contrast media applied was 34.5 ± 5.1 ml. All examinations were performed without complications.
Conclusion
CT perfusion of kidney allografts may help to differentiate between ATN and rejection.
Key points
•
Quantitative CT perfusion of renal transplants is feasible.
•
CT perfusion could help to non-invasively differentiate AR from ATN.
•
CT perfusion might make some renal biopsies unnecessary.
To assess the benefit of ultrasound (US) image fusion in the identifiability and assessment of the dignity of renal lesions.
25 patients with 29 renal lesions were investigated using standard US and ...CEUS (contrast enhanced US) with image fusion (CT or MRI). Identifiability and assessment of dignity was evaluated using cross-sectional images and US separately as well as using both US-techniques with additional image fusion. The respective modality was rated by two experienced radiologists (10 and 5 years of experience) using a (subjective) 5 point rank scale (1 = best).
Using CEUS, image fusion resulted in improved identifiability (score: 1.1 ± 0.4) and improved assessment of dignity (score 1.0 ± 0) of renal lesions than using cross sectional images (score 1.8 ± 1.2 and 3.8 ± 1.2 respectively) separately.
Image fusion improved the identifiability and the assessment of the dignity of renal lesions compared to using the respective modalities separately.
The aim of the study was to evaluate whether contrast enhanced ultrasound (CEUS) can improve the visualization of in-stent restenosis after carotid stenting of the internal carotid artery (ICA) in ...comparison to color-coded duplex sonography (CCDS) and power Doppler.
The study included the follow up of thirty patients after carotid artery stenting (CAS). Intrastenotic flow detection and lengths of in-stent restenosis were the main criteria. A high-end ultrasound machine (Siemens, ACUSON, Sequoia or S2000) with a multi-frequency linear 9 MHz or 15 MHz transducer was used to carry out contrast-enhanced ultrasound with SonoVue. In cases of treatment of a high degree in-stent stenosis intra-arterial digital subtraction angiography (DSA) was used.
All patients were examined using all diagnostic ultrasound tools of the study. In five patients (17%) an in-stent restenosis of the internal carotid artery (ICA) was found. Two patients need a reintervention. The results show that the contrast enhanced ultrasound could improve the diagnostic assessment capabilities in comparison to CCDS and power Doppler for patients with in-stent restenosis after carotid stenting of the ICA.
Contrast enhanced ultrasound is a reliable method for the evaluation of in-stent restenosis after carotid stenting of the ICA. CEUS provides a reduction in intrastenotic flow artefacts, resulting in better visualisation and detection of the complete length of the stenosis in comparison with CCDS and power Doppler. In order to elucidate hemodynamic changes, additional Doppler examinations are still necessary.
To compare the value of a portable ultrasound system and a high end ultrasound system in detection of endoleaks after EVAR.
In this retrospective study, a cohort of 25 patients underwent both ...standard examination using a portable ultrasound system (Philips VISIQ) and a second examination using a high end ultrasound system (Philips EPIQ 7). The examination included B-mode and color Doppler in detection of endoleaks. Additional the maximum diameter of the aneurysm was measured in two planes (right-left and ventral-dorsal). The gold standard was contrast-enhanced ultrasound (CEUS) in detection of endoleaks.
25 patients were included in the study. Patients were predominantly male (n = 23) with an average age of 73,30±7.82 years (range 54-85). Diameters of the treated aneurysms were in the right-left plane 5,32±1.88 cm and ventral-dorsal 4,99±1.78 cm using the high end system. Diameters of the treated aneurysms were in the right-left plane 5,30±1.82 cm and ventral-dorsal 4,87±1.74 cm using portable ultrasound system. In 80% of the cases CEUS could detect an endoleak. Whereas the high end system could detect in B-mode 40% and color Doppler 45% of the cases an endoleak. The portable system could detect in B-mode 30% and in color Doppler 35% of the cases an endoleak. On both systems in B-mode a false positive endoleak was found on the same patient. All high flow endoleaks, which needed intervention, could be detected on all systems.
The high end ultrasound system does not seem to have an additional advantage in the measurement of the aneurysm diameter. Due to a higher resolution, more endoleaks could be detected in B-mode and color Doppler by using the high end system. The presence of small endoleaks could only be detected by using contrast enhanced ultrasound on an high end ultrasound system. High flow endoleaks could be reliable seen on both systems.
Purpose
To evaluate feasibility of automatic software-based path proposals for CT-guided percutaneous biopsies.
Methods
Thirty-three patients (60
±
12 years) referred for CT-guided biopsy of focal ...liver lesions were consecutively included. Pre-interventional CT and dedicated software (FraunhoferMeVis Pathfinder) were used for (semi)automatic segmentation of relevant structures. The software subsequently generated three path proposals in downward quality for CT-guided biopsy. Proposed needle paths were compared with consensus proposal of two experts (comparable, less suitable, not feasible). In case of comparable results, equivalent approach to software-based path proposal was used. Quality of segmentation process was evaluated (Likert scale, 1
=
best, 6
=
worst), and time for processing was registered.
Results
All biopsies were performed successfully without complications. In 91 % one of the three automatic path proposals was rated comparable to experts’ proposal. None of the first proposals was rated not feasible, and 76 % were rated comparable to the experts’ proposal. 7 % automatic path proposals were rated not feasible, all being second choice (
n
=
1
) or third choice (
n
=
6
). In 79 %, segmentation at least was good. Average total time for establishing automatic path proposal was 42
±
9 s.
Conclusion
Automatic software-based path proposal for CT-guided liver biopsies in the majority provides path proposals that are easy to establish and comparable to experts’ insertion trajectories.
The purpose of this study was to evaluate whether image fusion with contrast enhanced ultrasound (CEUS) and CT is effective in the pre-, intra- and post-interventional management of liver lesions ...during microwave or radiofrequency ablation.
Fifteen patients with a single hepatocellular carcinoma (HCC) up to 3 cm diameter, identified on both contrast-enhanced CT (Siemens Somatom Definition AS and Definition Edge, Siemens Healthcare, Erlangen, Germany) and ultrasound (Siemens ACUSON S2000™ or S3000™, Siemens Healthcare, Erlangen, Germany) were retrospectively enrolled between July 2011 and May 2012. Either automatic registration or plane match registration was chosen on CT and ultrasound for the pre-, intra- and postinterventional management of all treated liver lesions during microwave or radiofrequency ablation. Using conventional ultrasound B-mode, CEUS and image fusion including B-mode and CEUS the detectability of the liver lesions was evaluated semi-quantitatively by comparing the image sequences in a consensus reading. Eight patients underwent radiofrequency ablation and seven patients underwent microwave ablation.
All patients were examined using all diagnostic ultrasound tools of the study. The results show that the procedure is easy and convenient to perform, as well as efficient. The co-registration procedure took approximately 5 to 10 minutes depending on the amount of DICOM volume-data and the habitus of the patient. The results show that the use of image fusion with CT and contrast-enhanced ultrasound could improve the diagnostic assessment capabilities in comparison to the examination without image fusion in the pre-, intra- and postinterventional management of malignant liver lesions during thermal ablation.
Percutaneous thermal ablation guided by contrast-enhanced ultrasound and image fusion seems to be an efficient approach for malignant liver lesions especially if these are not clearly demarcated by B-mode. The use of the image fusion technique in the pre-, intra- and postinterventional management can increase operator confidence, the accuracy of the procedure, and technical success in real time.
To evaluate if vascular and pulmonary parenchymal enhancement values in dual-energy (DE) CT pulmonary angiography (CTPA) can suggest the diagnosis of pulmonary congestion.
DE-CTPA images of 90 out of ...1321 patients negative for pulmonary embolism showed signs of congestive heart failure. We measured DE-derived pulmonary parenchymal perfused blood volume (PBV), pulmonary artery (PA) and left atrium (LA) enhancement values in these patients and in 142 control patients. Enhancement values were compared between the populations and correlated with serum values of B-type natriuretic peptide (BNP) and proBNP, where available.
No significant difference of PBV but significant differences of mean PA and LA enhancement and individual enhancement differences (PA - LA) were found between the populations. PA - LA was higher in patients with elevated BNP and proBNP and was positively correlated with these values. Receiver operating characteristic analysis revealed a moderate discriminatory power of the PA - LA difference for the presence of cardiac biomarker elevations.
PBV in DE-CTPA is not altered in patients with signs of congestive heart failure. However, differences in enhancement values in the pre- and post-pulmonary vessels were found in comparison with the control population.
Altered pulmonary vascular haemodynamics in pulmonary venous congestion are not reflected in dual-energy-derived PBV maps. In the diagnosis of left heart failure in patients with chest pain and dyspnoea, density measurements in the pulmonary artery and in the left atrium in CTPA images may be a helpful diagnostic tool.
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