The hippocampus is a small internal temporal cerebral structure which plays a primordial role in memory mechanisms. Magnetic resonance imaging (MRI) is the preferred method for analysing this ...structure. In older adults, dementia is the major cause of hippocampal anomalies, particularly atrophic anomalies, however, differential diagnoses involving other specific pathologies should also be recognised in this population. Most acute or recent hippocampal damage is detected based on MRI signal abnormalities. The aim of this article is to provide an iconographic review of normal and pathological hippocampal imaging in older adults with degenerative, infectious, vascular, inflammatory, tumoural, toxic, and metabolic disorders.
Many numerical observers have been proposed in the framework of task-based approach for medical image quality assessment. However, the existing numerical observers are still limited in diagnostic ...tasks: the detection task has been largely studied, while the localization task concerning one signal has been little studied and the localization of multiple signals has not been studied yet. In addition, most existing numerical observers need a priori knowledge about all the parameters of the underdetection signals, while only a few of them need at least two signal parameters. In this paper, we propose a novel numerical observer called the perceptually relevant channelized joint observer (PCJO), which cannot only detect but also localize multiple signals with unknown amplitude, orientation, size and location. We validated the PCJO for predicting human observer task performance by conducting a clinically relevant free-response subjective experiment in which six radiologists (including two experts) had to detect and localize multiple sclerosis (MS) lesions on magnetic resonance (MR) images. By using the jackknife alternative free-response operating characteristic (JAFROC) as the figure of merit (FOM), the detection-localization task performance of the PCJO was evaluated and then compared to that of the radiologists and two other numerical observers-channelized hotelling observer (CHO) and Goossenss CHO for detecting asymmetrical signals with random orientations. Overall, the results show that the PCJO performance was closer to that of the experts than to that of the other radiologists. The JAFROC1 FOMs of the PCJO (around 0.75) are not significantly different from those of the two experts (0.7672 and 0.7110), while the JAFROC1 FOMs of the numerical observers mentioned above (always over 0.84) outperform those of the experts. This indicates that the PCJO is a promising method for predicting radiologists' performance in the joint detection-localization task.
Graft copolymers were synthesized by direct condensation of methoxy‐poly(ethylene glycol) (MePEG) or methoxy‐poly(lactic acid) (MePLA) onto a reactive polyhydroxyalkanoate (PHA) backbone in organic ...solvent. Side carboxylic groups of the PHA were coupled with end hydroxyl groups of MePEG or MePLA in the presence of N,N′‐dicylohexylcarbodiimide (DCC). Graft copolymers were characterized by 1H NMR spectroscopy and size exclusion chromatography (SEC). NMR spectra of PHA‐g‐PEG and PHA‐g‐PLA showed the presence of significant amounts of PEG and PLA, respectively. No noticeable unreacted PEG or PLA were detected in SEC chromatograms. Grafting of hydrophilic polymers chains as PEG or biodegradable oligomers as PLA onto PHA backbone will generate polyesters with a more rapid water uptake and faster biodegradation rates. These PHA polymers conjugates could be interesting for bioactive agent delivery systems.
Background/Aims: Evaluation of the degree of hepatic fibrosis is especially important in patients with chronic liver disease. Our aim was to study the diagnostic accuracy of abdominal ultrasonography ...for cirrhosis or fibrosis.
Methods: Twenty-three clinical (
n=12) and Doppler ultrasonic (
n=11) variables were recorded in 243 patients with chronic (alcoholic and viral) liver disease under conditions close to those of clinical practice. Fibrosis was classified into six grades by two pathologists. Diagnostic accuracy was evaluated by discriminant analysis, first globally using all variables, then by stepwise analysis.
Results: A) Diagnosis of cirrhosis: 1) whole group (
n=243): diagnostic accuracy was globally 84%, and 84% with two variables: spleen length, portal velocity; 2) compensated chronic liver disease (
n=191): diagnostic accuracy was globally 85%, and 82% with two variables: liver surface, liver length (right kidney); 3) alcoholic compensated chronic liver disease (
n=109): diagnostic accuracy was globally 86%, and 88% with two variables: spleen length, liver length (middle clavicle); 4) viral compensated chronic liver disease (
n=83): diagnostic accuracy was globally 86% and 86% with one variable: liver surface. By subtracting the proportion of patients who could not be investigated due to anatomical limitations, the highest calculated univariate diagnostic accuracy decreased by 7%. B) Diagnosis of fibrosis: diagnostic accuracy was globally 84% for extensive fibrosis.
Conclusions: Cirrhosis can be correctly diagnosed in 82–88% of patients with chronic liver disease using a few ultrasonographic signs. However, the diagnostic accuracy of ultrasound is decreased by the anatomical limitations of this technique.
Abstract We report on the safety and feasibility of autologous tumor cell vaccination combined with infusion of granulocyte-macrophage colony-stimulating factor by a programmable pump in the ...treatment of recurrent malignant gliomas. The programmable pump is a promising tool used to infuse cytokines subcutaneously for vaccination. Our trial enrolled nine patients who had undergone surgery, radiation and had been successfully weaned off steroids. Unfortunately, only five patients completed the protocol and were monitored for side effects, local reactions, delayed-type hypersensitivity (DTH) responses and survival. The treatment was well tolerated. Two patients developed DTH reactions after vaccination and three patients had an unusually long survival without any other treatment. Despite the few patients treated, the results of this trial are encouraging. This study also highlights the specific difficulties encountered in vaccination programs for the treatment of glioma.
Magnetic resonance imaging (MRI) is susceptible to visual artifacts that can degrade the perceptual image quality, potentially leading to inaccurate or inefficient diagnoses in clinical practice. It ...is critical to evaluate the perceptual image quality and build this technique into clinical solutions. In a previous study, an MRI database was created for image quality assessment (IQA), where various types of MRI artifacts with different degrees of degradation were simulated. Application specialists assessed the image quality; however, radiologists’ perception of MRI image quality remains unknown. To make IQA clinically relevant, in this paper we conduct a new subjective experiment where 13 radiologists rated the quality of images contained in the MRI database. Based on this subjective IQA benchmark named RAD-IQMRI, we evaluate the performance of state-of-the-art objective IQA models, providing insights into their application for MRI image quality assessment in clinical settings.
The authors report a case of one patient from a family carrying the homoplasmic Leber hereditary optic neuropathy (LHON) G11778A mitochondrial DNA mutation with papilloedema 9 months prior to the ...acute stage of LHON and still present at the onset of visual loss. During the vision loss, the MRI demonstrated a T2 hyperintensity and an enhancement of the prechiasmal left optic nerve, suggesting the existence of an inflammatory mechanism. A retrospective review of the chart of two others members of the same family, with bilateral optic disc oedema at onset of the vision loss, suggests that the relationship of papilloedema and acute phase of LHON may not be just a coincidence, at least in this family. The visual loss related to LHON could have been triggered in the setting of the chronic papilloedema, associated with the intracranial hypertension.
Low quality medical images can lead to inaccurate interpretation and diagnosis. Therefore, it is important to understand radiologists' perception of distortions in visual content. In this study, 12 ...radiologists with different degrees of experience scored MRI images of varying levels of quality. Statistical analyses were conducted to reveal the influence of the radiologists' experience on their perception of image quality. In scoring images of joints, brain and liver, the highly experienced radiologists gave significantly higher scores than less experienced radiologists. In scoring images of fetus and spine, there were no significant differences in scores between groups with different degrees of experience. No radiologists had expertise in breast images, and their experience in other anatomical areas did not significantly affect scoring of breast images. Overall, highly experienced radiologists gave higher scores for images with edge ghosting, plain ghosting or white noise than radiologists with less experience. The findings will provide a reference for determining or improving image quality standards in clinical practice.
Geometrical parameters, including arterial bifurcation angle, tortuosity, and arterial diameters, have been associated with the pathophysiology of intracranial aneurysm (IA) formation. The aim of ...this study was to investigate whether these parameters were present before or if they resulted from IA formation and growth.
Patients from nine academic centers were retrospectively identified if they presented with a de novo IA or a significant IA growth on subsequent imaging. For each patient, geometrical parameters were extracted using a semi-automated algorithm and compared between bifurcations with IA formation or growth (aneurysmal group), and their contralateral side without IA (control group). These parameters were compared at two different times using univariable models, multivariable models, and a sensitivity analysis with paired comparison.
46 patients were included with 21 de novo IAs (46%) and 25 significant IA growths (54%). The initial angle was not different between the aneurysmal and control groups (129.7±42.1 vs 119.8±34.3; p=0.264) but was significantly wider at the final stage (140.4±40.9 vs 121.5±34.1; p=0.032), with a more important widening of the aneurysmal angle (10.8±15.8 vs 1.78±7.38; p=0.001). Variations in other parameters were not significant. These results were confirmed by paired comparisons.
Our study suggests that wider bifurcation angles that have long been deemed causal factors for IA formation or growth may be secondary to IA formation at pathologic bifurcation sites. This finding has implications for our understanding of IA formation pathophysiology.
PDF
