Normal and pathological imaging of the hippocampus in geriatric patients.

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.

[Normal and pathological hippocampal imaging in geriatric patients]. / Imagerie normale et pathologique de l'hippocampe en gériatrie.

The hippocampus is a small internal temporal cerebral structure, which plays a primordial role in the mechanisms of memory. Magnetic resonance imaging (MRI) is the reference imaging modality for the hippocampal analysis. In older adults, dementia represents the majority of hippocampal diseases, but other specific pathologies must be known in the differential diagnosis. Many hippocampal abnormalities are represented by a loss of substance (atrophy). However, most acute or recent hippocampal damage is detected by MRI signal abnormalities. The aim of this article is to offer a pictorial review of the normal and pathological hippocampal aspects of older adults, during degenerative, infectious, vascular, inflammatory, tumoral, toxic and metabolic disorders.

A perceptually relevant channelized joint observer (PCJO) for the detection-localization of parametric signals.

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.

Autologous tumor cell vaccination plus infusion of GM-CSF by a programmable pump in the treatment of recurrent malignant gliomas.

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.

Papilloedema and MRI enhancement of the prechiasmal optic nerve at the acute stage of Leber hereditary optic neuropathy.

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.

Ruptured aneurysm on a double origin of the posterior inferior cerebellar artery: a pathological entity in an anatomical variation. Report of two cases and review of the literature.

The posterior inferior cerebellar artery (PICA) is known to be very variable, and some of its anatomical variations can explain ischemic complications that occur during endovascular treatment of aneurysms. The authors report two cases of anatomical variation of the PICA that they have called its double origin, one of which gave rise to an aneurysm. The first patient was a 36-year-old man who presented with a subarachnoid hemorrhage related to the rupture of a PICA aneurysm. The aneurysm was treated by the endovascular route. Selective and superselective studies showed that the PICA origin was low on the fourth segment of the vertebral artery (VA). The aneurysm was located on an anastomosis between the PICA and a small upper arterial branch originating from the VA. Embolization was performed through the small branch with no problem, but a lateral medullary infarct followed, probably due to occlusion of the perforating vessels. The same anatomical variation was incidentally discovered in the second patient. To the authors' knowledge, neither this anatomical variation of the PICA nor the aneurysm's topography have been previously described angiographically. This highlights the role of angiography in pretreatment evaluation of aneurysms especially when perforating vessels or small accessory branches that are poorly visualized on angiographic studies are concerned, as in the territory of the PICA. Anatomy is sometimes unpredictable, and the surgeon must be very careful when confronted with these variations because they are potentially dangerous for endovascular treatment.