Search results for "Nuclear Medicine and Imaging"
showing 10 items of 2516 documents
RCBF-quantification with 99mTc-HMPAO-SPECT: theory and first results.
1989
The activity concentrations of 99mTc-HMPAO in brain after intravenous injection were evaluated in 25 patients using SPECT. With additional first pass studies of heart and brain with the short lived isotope 195mAu, the cardiac output and the mean cerebral transit times of the patients were measured a short time before the HMPAO injection. The time dependence of 99mTc-HMPAO activity in the brain was registered during the first 5 min after injection over both hemispheres. Using a simplified three compartment model it was possible to calculate the mean retention fraction of HMPAO in brain from the time activity curves. It could be shown that the regional cerebral blood flow in ml/min per 100 g …
Assessment of normal patellar cartilage volume and thickness using MRI: an analysis of currently available pulse sequences.
1996
Objective. The objective of this study was to analyse the potential of magnetic resonance imaging for valid determination of patellar cartilage thickness, comparing currently available pulse sequences. Design. In six patients and one cadaver the cartilage was repetitively imaged employing three spin-echo and six three-dimensional gradient-echo sequences. In the cadaveric specimen the total volume and the regional distribution of cartilage thickness were assessed and compared with the values obtained from anatomical sections by image analysis. Results and conclusions. The FLASH and fat-suppressed FLASH sequences allowed the most accurate determination of the cartilage volume and thickness. F…
Facilitating cartilage volume measurement using MRI.
2010
To compare quantitative cartilage volume measurement (CVM) using different slice thicknesses.Ten knees were scanned with a 1.5T MRI (Sonata, Siemens, Erlangen, Germany) using a 3D gradient echo sequence (FLASH, fast low-angle shot). Cartilage volume of the medial and lateral tibial plateau was measured by two independent readers in 1.5mm, 3.0mm and 5.0mm slices using the Argus software application. Accuracy and time effectiveness served as control parameters.Determining cartilage volume, time for calculation diminished for the lateral tibial plateau from 384.6+/-127.7s and 379.1+/-117.6s to 214.9+/-109.9s and 213.9+/-102.2s to 122.1+/-60.1s and 126.8+/-56.2s and for the medial tibial platea…
Magnetic resonance chondro-crassometry (MR CCM): a method for accurate determination of articular cartilage thickness?
1996
A method for the assessment of articular cartilage thickness based on MRI is presented and its accuracy and reproducibility tested. Six specimens of human patellae were imaged, using a fat-suppressed FLASH 3D sequence, and sectioned with a high-precision band saw. The regional distribution of articular cartilage thickness was determined from the MR images and from the anatomical sections (intervals of 0.5 mm). With image analysis 50-90% of the image points were found to lie within exactly the same thickness interval in corresponding patterns, and less than 17% deviated more than 0.5 mm. More than 85% of all pixels were reproducible with MRI after new positioning of the joint. No influence o…
Determination of knee joint cartilage thickness using three-dimensional magnetic resonance chondro-crassometry (3D MR-CCM)
1996
The objective of this article was to analyze the accuracy and precision with which the quantitative distribution of articular cartilage can be determined in the knee joint using MRI. A three-dimensional (3D) technique that accounts for the out-of-plane deviation of the interface normal in strongly curved joint surfaces (3D MR-CCM) has been developed for cartilage thickness measurements. Eight cadaveric knee-joint specimens and six volunteers were imaged using a fat-suppressed gradient-echo sequence at a resolution of 2 x 0.31 x 0.31 mm3. Cartilage volumes and topographical thickness maps were obtained and compared with those derived from anatomical sections by image analysis. The deviation …
Reduced interhemispheric structural connectivity between anterior cingulate cortices in borderline personality disorder
2008
Functional and structural alterations of the anterior cingulate cortex (ACC), a key region for emotional and cognitive processing, are associated with borderline personality disorder (BPD). However, the interhemispheric structural connectivity between the left and right ACC and between other prefrontal regions in this condition is unknown. We acquired diffusion-tensor imaging data from 20 healthy women and 19 women with BPD and comorbid attention-deficit hyperactivity disorder (ADHD). Interhemispheric structural connectivity between both sides of the ACC, dorsolateral prefrontal cortices and medial orbitofrontal cortices was assessed by a novel probabilistic diffusion tensor-based fiber tra…
The Resilient Emotional Brain: A Scoping Review of the Medial Prefrontal Cortex and Limbic Structure and Function in Resilient Adults With a History …
2020
Childhood Maltreatment (CM) is one of the strongest predictors of adult mental illness, though not all adults with CM develop psychopathology. Here, we describe the structure and function of emotional brain regions that may contribute to resilient functioning after CM. We review studies that report medial prefrontal cortex (mPFC), amygdala and hippocampus (‘limbic regions’) structure, function, and/or connections, in resilient (i.e., adults reporting CM without psychopathology) vs. vulnerable (i.e., adults reporting CM with psychopathology), or healthy adults (adults without CM with no psychopatology). We find that resilient adults have larger hippocampal grey and white matter volume, and i…
Lifestyle changes in cancer patients undergoing curative or palliative chemotherapy: is it feasible?
2017
This study aimed to explore the feasibility of an individualized comprehensive lifestyle intervention in cancer patients undergoing curative or palliative chemotherapy.At one cancer center, serving a population of 180,000, 100 consecutive of 161 eligible newly diagnosed cancer patients starting curative or palliative chemotherapy entered a 12-month comprehensive, individualized lifestyle intervention. Participants received a grouped startup course and monthly counseling, based on self-reported and electronically evaluated lifestyle behaviors. Patients with completed baseline and end of study measurements are included in the final analyses. Patients who did not complete end of study measurem…
Enhancement pattern of small hepatocellular carcinoma (HCC) at contrast-enhanced US (CEUS), MDCT, and MRI: intermodality agreement and comparison of …
2012
OBJECTIVE:To evaluate agreement between contrast-enhanced ultrasound (CEUS), multi-detector row computed tomography (MDCT) and magnetic resonance imaging (MRI) for the assessment of typical and atypical enhancement patterns of small hepatocellular carcinoma (HCC); and to compare diagnostic sensitivity of 2005 and 2010 American Association for the Study of Liver Diseases (AASLD) guidelines. MATERIALS AND METHODS: Between January 2008 and December 2009, we included cirrhotic patients with newly diagnosed 10-20 mm HCC imaged at two contrast-enhanced imaging techniques among CEUS, MDCT, and MRI. Dynamic studies were reviewed by two radiologists to assess enhancement pattern. Percentage of cases…
Imaging findings of liver resection using a bipolar radiofrequency electrosurgical device—Initial observations
2010
Abstract Objective To assess contrast-enhanced US (CEUS), computed tomography (CT) and magnetic resonance (MR) imaging findings and serial changes of the treated area at follow-up in patients who underwent liver resection using a bipolar radiofrequency electrosurgical device. Methods Imaging findings of 27 patients with resected hepatocellular carcinomas (HCCs) ( n = 24) and metastases ( n = 3) (mean size: 2.6 cm), were retrospectively evaluated. Two readers assessed: the (a) presence, (b) thickness, (c) shape and (d) echogenicity (CEUS)/attenuation (CT)/signal intensity (MR imaging) at coagulated site and the (e) presence of residual tumor of the bipolar radiofrequency electrosurgical de…