Correlation between choline level and Gd-DTPA enhancement in patients with brain metastases of mammary carcinoma

Single voxel 1HH double spin-echo MR spectroscopy was used to examine 15 cases of brain metastasis of mammary carcinoma (18 lesions) in relation to Gd-DTPA enhanced MR imaging. For lesions larger than 50% of MRS voxel size, there was significant correlation between Gd-DTPA-enhanced MRI signal and MRS-detected signal of choline (Cho) containing compounds (r = 0.86, P < 0.01; n = 8). The observed loss of correlation when including the smaller lesions was overcome by correcting for partial volume effects (r = 0.69, P < 0.002; n = 18). Metastasis spectra showed increased Cho compared with control spectra, except for those lesions showing detectable lactate (Lact) signal. The detection of Lact in four of the larger lesions coincided with comparatively low levels of creatine (Cr) and Cho and heterogeneous Gd-DTPA enhancement (ring-enhancement). It was concluded that in brain metastases of mammary carcinoma Lact represents a product of ischemia preceding/during tissue decay resulting in central necrosis, rather than tumor specific metabolism resulting in increas

Automatic Pulmonary Nodule Detection in CT Scans Using Convolutional Neural Networks Based on Maximum Intensity Projection

Accurate pulmonary nodule detection is a crucial step in lung cancer screening. Computer-aided detection (CAD) systems are not routinely used by radiologists for pulmonary nodule detection in clinical practice despite their potential benefits. Maximum intensity projection (MIP) images improve the detection of pulmonary nodules in radiological evaluation with computed tomography (CT) scans. Inspired by the clinical methodology of radiologists, we aim to explore the feasibility of applying MIP images to improve the effectiveness of automatic lung nodule detection using convolutional neural networks (CNNs). We propose a CNN-based approach that takes MIP images of different slab thicknesses (5 mm, 10 mm, 15 mm) and 1 mm axial section slices as input. Such an approach augments the two-dimensional (2-D) CT slice images with more representative spatial information that helps discriminate nodules from vessels through their morphologies. Our proposed method achieves sensitivity of 92.67% with 1 false positive per scan and sensitivity of 94.19% with 2 false positives per scan for lung nodule detection on 888 scans in the LIDC-IDRI dataset. The use of thick MIP images helps the detection of small pulmonary nodules (3 mm-10 mm) and results in fewer false positives. Experimental results show that utilizing MIP images can increase the sensitivity and lower the number of false positives, which demonstrates the effectiveness and significance of the proposed MIP-based CNNs framework for automatic pulmonary nodule detection in CT scans. The proposed method also shows the potential that CNNs could gain benefits for nodule detection by combining the clinical procedure.Comment: Submitted to IEEE TM

Breath-hold MR cholangiopancreatography with three-dimensional, segmented, echo-planar imaging and volume rendering

End-expiration, 21-second breath-hold, three-dimensional magnetic resonance (MR) cholangiopancreatography (MRCP) was developed with segmented echo-planar imaging. In 15 healthy subjects and 14 randomly selected patients undergoing liver studies, three-dimensional MRCP images were obtained and volume rendered. In 15 (100%) healthy subjects and 13 (93%) patients, clear depiction of biliary, hepatic, and pancreatic ducts (with lumen diameter of at least 2 mm) was possible with good signal-to-noise ratio

Detection of liver metastases from colorectal carcinoma: Is there a place for routine computed tomography arteriography?

Background. A prospective evaluation of the liver by preoperative ultrasonography, conventional computed tomography (CT), and continuous CT angiography (CCTA) was performed in 60 patients with primary or secondary colorectal carcinoma. Methods. The standards of reference were palpation of the liver and intraoperative ultrasonography. The imaging techniques were assessed independently of each other. Results. In 37 patients 105 liver metastases were identified; 23 patients had no metastases. CCTA had a high sensitivity of 94% (99 lesions identified) in contrast to ultrasonography (48%) and conventional CT (52%). The superiority of CCTA was also manifest in lesions less than 1 cm in diameter. However, the high sensitivity was accompanied by a high false-positive rate, particularly because of variations in the perfusion of normal liver parenchyma. Overall, CCTA had the highest accuracy (74%) compared with ultrasonography and CT (both 57%). The data indicate that preoperative ultrasonography and conventional CT have low sensitivity in the detection of liver metastases. Conclusions. Although CCTA seems to be superior to other preoperative imaging techniques, the too low specificity will hamper its routine application in patients with hepatic metastases from colorectal carcinoma

Quantitative image analysis for the detection of motion artefacts in coronary artery computed tomography

Multi detector-row CT (MDCT), the current preferred method for coronary artery disease assessment, is still affected by motion artefacts. To rule out motion artefacts, qualitative image analysis is usually performed. Our study aimed to develop a quantitative image analysis for motion artefacts detection as an added value to the qualitative analysis. An anthropomorphic moving heart phantom with adjustable heart-rate was scanned on 64-MDCT and dual-source-CT. A new software technique was developed which detected motion artefacts in the coronaries and also in the myocardium, where motion artefacts are more apparent; with direct association to the qualitative analysis. The new quantitative analysis managed to detect motion artefacts in phantom scans and relate them to artefact-induced vessel stenoses. Quantifying these artefacts at corresponding locations in the myocardium, artefact-induced vessel stenosis findings could be avoided. In conclusion, the quantitative analysis together with the qualitative analysis rules out artefact-induced stenosis

Solid breast neoplasms: Differential diagnosis with pulsed Doppler ultrasound

In this prospective study, duplex Doppler ultrasound was used in 95 consecutive patients with solid breast masses to evaluate the presence of neovascular flow. A positive Doppler signal, i.e., a Doppler shift frequency of more than 1 kHz using a 5 MHz insonating frequency, was found in 34 of 57 patients with a carcinoma, and also in three patients with a benign condition. These results indicate that negative findings with pulsed Doppler ultrasound cannot be used to exclude malignancy. However, a frequency shift of more than 1 kHz indicates a high probability for malignancy. In our study a high frequency shift was not related to tumor size. We also evaluated the correlation between a high frequency shift and axillary nodal metastasis. According to our results there is a very low chance of axillary metastasis when no high frequency shifts are found

Renal Function Is Related to Severity of Coronary Artery Calcification in Elderly Persons: The Rotterdam Study

Background: Coronary artery calcification (CAC) has been proposed to be the underlying mechanism of the increased risk of coronary heart disease with reductions in glomerular filtration rate (GFR). Since renal function diminishes with aging we examined the association between GFR and CAC in the Rotterdam Study, a population-based study of elderly individuals. Methods: The study was performed in 1703 subjects without a history of coronary heart disease. GFR was estimated using the modification of diet in renal disease equation. We used analysis of covariance to test for mean differences in CAC between GFR tertiles. Results: The mean CAC scores in the middle and lowest GFR tertile did not significantly differ from the mean CAC score in the highest GFR tertile (geometric mean CAC score 4.1 and 4.3 vs 4.2). In a multivariable model the mean CAC score did also not differ between the GFR tertiles. As the interaction term between age and GFR was significant (P = 0.037), we divided the population in two age categories based on median age of 70 years. Below 70 years, the mean CAC scores did not differ between the GFR tertiles. Above median age, mean CAC score in the lowest GFR tertile was significantly higher than the mean CAC score in the highest tertile in a multivariable model (CAC 4.9 vs 4.5, p = 0.010). Conclusion: In this population-based study we observed that the association between CAC and GFR is modified by age. In participants at least 70 years of age, a decrease in GFR was associated with increased CAC