Fabrice Bonneville

Parkinson's disease with camptocormia

Background: Camptocormia is defined as an abnormal flexion of the trunk that appears when standing or walking and disappears in the supine position. The origin of the disorder is unknown, but it is usually attributed either to a primary or a secondary paravertebral muscle myopathy or a motor neurone disorder. Camptocormia is also observed in a minority of patients with parkinsonism. Objective: To characterise the clinical and electrophysiological features of camptocormia and parkinsonian symptoms in patients with Parkinson’s disease and camptocormia compared with patients with Parkinson’s disease without camptocormia. Methods: Patients with parkinsonism and camptocormia (excluding patients with multiple system atrophy) prospectively underwent a multidisciplinary clinical (neurological, neuropsychological, psychological, rheumatological) and neurophysiological (electromyogram, ocular movement recording) examination and were compared with age-matched patients with Parkinson’s disease without camptocormia. Results: The camptocormia developed after 8.5 (SD 5.3) years of parkinsonism, responded poorly to levodopa treatment (20%) and displayed features consistent with axial dystonia. Patients with camptocormia were characterised by prominent levodopa-unresponsive axial symptoms (ie, axial rigidity, gait disorder and postural instability), along with a tendency for greater error in the antisaccade paradigm. Conclusion: We suggest that (1) the salient features of parkinsonism observed in patients with camptocormia are likely to represent a specific form of Parkinson’s disease and camptocormia is an axial dystonia and (2) both camptocormia and parkinsonism in these patients might result from additional, non-dopaminergic neuronal dysfunction in the basal ganglia.

Magnetic resonance imaging of pituitary adenomas.

Today, MR is the only method needed for the morphological investigation of endocrine-active pituitary adenomas. In acromegaly and Cushing’s syndrome, the therapeutic attitude is directly dictated by MR data. We present the MR aspect of pituitary adenomas according to size, sex, age, endocrine activity and a few particular conditions such as hemorrhagic pituitary adenomas, pituitary adenomas during pregnancy, cavernous sinus invasion and postsurgical changes. When an intrasellar mass extending out of the sella turcica is detected, the goal of the MR examination is to indicate precisely the origin of the tumor, its extension in relation to the various surrounding structures, its structure and its enhancement in order to help in the differential diagnosis. Demonstration of very small pituitary adenomas remains a challenge. When SE T1- and Turbo SE T2-weighted sequences are non-diagnostic, enhanced imaging becomes mandatory; half-dose gadolinium injection, delayed sequence, dynamic imaging can be of some help.

Imaging of cerebellopontine angle lesions: an update. Part 2: intra-axial lesions, skull base lesions that may invade the CPA region, and non-enhancing extra-axial lesions

Computed tomography (CT) and magnetic resonance (MR) imaging reliably demonstrate typical features of vestibular schwannomas or meningiomas in the vast majority of mass lesions responsible for cerebellopontine angle (CPA) syndrome. However, a large variety of unusual lesions can also be encountered in the CPA. Covering the entire spectrum of lesions potentially found in the CPA, these articles explain the pertinent neuroimaging features that radiologists need to know to make clinically relevant diagnoses in these cases, including data from diffusion- and perfusion-weighted imaging or MR spectroscopy, when available. A diagnostic algorithm based on the lesion’s site of origin, shape and margins, density, signal intensity and contrast material uptake is also proposed. Non-enhancing extra-axial CPA masses are cystic (epidermoid cyst, arachnoid cyst, neurenteric cyst) or contain fat (dermoid cyst, lipoma). Tumours can also extend into the CPA by extension from the skull base (paraganglioma, chondromatous tumours, chordoma, cholesterol granuloma, endolymphatic sac tumour). Finally, brain stem or ventricular tumours can present with a significant exophytic component in the CPA that may be difficult to differentiate from an extra-axial lesion (lymphoma, hemangioblastoma, choroid plexus papilloma, ependymoma, glioma, medulloblastoma, dysembryoplastic neuroepithelial tumour).

Imaging of cerebellopontine angle lesions: an update. Part 1: enhancing extra-axial lesions

Computed tomography (CT) and magnetic resonance (MR) imaging reliably demonstrate typical features of vestibular schwannomas or meningiomas in the vast majority of mass lesions in the cerebellopontine angle (CPA). However, a large variety of unusual lesions can also be encountered in the CPA. Covering the entire spectrum of lesions potentially found in the CPA, these articles explain the pertinent neuroimaging features that radiologists need to know to make clinically relevant diagnoses in these cases, including data from diffusion and perfusion-weighted imaging or MR spectroscopy, when available. A diagnostic algorithm based on the lesion’s site of origin, shape and margins, density, signal intensity and contrast material uptake is also proposed. Part 1 describes the different enhancing extra-axial CPA masses primarily arising from the cerebellopontine cistern and its contents, including vestibular and non-vestibular schwannomas, meningioma, metastasis, aneurysm, tuberculosis and other miscellaneous meningeal lesions.

Gait and balance disorders in Parkinson's disease: impaired active braking of the fall of centre of gravity.

Gait and balance disorders are common in Parkinsons disease (PD), but its pathophysiology is still poorly understood. Step length, antero‐posterior, and vertical velocities of the center of gravity (CG) during gait initiation were analyzed in 32 controls and 32 PD patients, with and without levodopa, using a force platform. Brain volumes and mesencephalic surface area were measured in PD patients. During the swing limb period, controls showed a fall in the CG, which was reversed before foot‐contact indicating active braking of the CG fall. In PD patients, without levodopa, step length and velocity were significantly reduced and no braking occurred before foot‐contact in 22 patients. With levodopa, step length and velocity increased in all patients and 7 patients improved their braking capacity. PD patients with normal braking (n = 17) had significantly lower gait and balance disorder scores and higher normalized‐mesencephalic surface areas compared to patients with impaired braking (n = 15). The decreased step length and velocity, characteristic of PD, mainly result from degeneration of central dopaminergic systems. The markedly decreased braking capacity observed in half the PD patients contributes to their gait disorders and postural instability, perhaps as a result of nondopaminergic lesions, possibly at the mesencephalic level.

High-Resolution MR Imaging of the Cervical Arterial Wall: What the Radiologist Needs to Know

The emergence of high-resolution rapid imaging methods has enabled magnetic resonance (MR) imagers to noninvasively image the fine internal structure of cervical arterial walls. In this article, a comprehensive guide to performing high-resolution MR imaging of cervical arteries is provided, including the choice of coils, sequences, and imaging parameters, as well as tips for optimal image quality. Explanations and illustrations are given of using high-resolution MR imaging to quantify plaque volume, determine atherosclerotic plaque burden, depict plaque composition, and ultimately identify unstable plaque before it leads to a clinical event. Finally, the role of high-resolution MR imaging in the diagnosis of cervical dissection and inflammatory disease of the arterial wall is emphasized.

Flow diversion treatment of complex bifurcation aneurysms beyond the circle of Willis: a single-center series with special emphasis on covered cortical branches and perforating arteries

Background Data regarding anatomic and clinical results of flow diversion treatment in complex bifurcation aneurysms of the anterior circulation are scarce. Objective To present our results of treatment of these lesions with special emphasis on the fate of ‘jailed’ cortical branches and perforating arteries. Methods Seventeen patients were treated with flow diverters (FDs) for 18 aneurysms of the middle cerebral artery bifurcation (n=13) and the anterior communicating artery complex (n=5). Nineteen cortical branches were covered. A single FD was used in all patients. Results At latest follow-up (mean 7.9 months; range 3–36; median 4.0) 2/19 (10.5%) of the covered branches were occluded, 9/19 (47.4%) showed a decreased caliber and the remaining branches were unchanged. All branch modifications were clinically asymptomatic. Mortality and permanent morbidity were 0%. Symptomatic ischemic events in perforator territories occurred in three patients (17.6%), which were reversible in all of them within 24 h. Follow-up MRI disclosed asymptomatic lacunar defects corresponding to covered perforating artery territories in five patients (29.4%). Altogether, perforator lesions—symptomatic and asymptomatic—occurred in 7/17 patients (41.2%). 33.3% of the aneurysms were occluded at latest follow-up; decreased diameters were seen in the other 66.7%. Conclusions Flow diversion of bifurcation aneurysms is feasible with low rates of permanent morbidity and mortality. Caliber reduction and asymptomatic occlusion of covered cortical branches seems to be common, yet ischemic complications are rather linked to perforator occlusions. Our results on aneurysm occlusion rates are preliminary and longer follow-up periods are warranted.

Camptocormia and Parkinson's disease: MR imaging

Camptocormia is characterized by an excessive anterior flexion of the spine that appears only when standing or walking. The origin of this symptom remains unknown, but recent clinical reports of camptocormia associated with Parkinson’s disease (PD) suggest cerebral involvement in the pathogenesis of camptocormia. This study was undertaken to investigate the hypothesis that camptocormia in PD has a central origin. Seventeen PD patients with camptocormia were prospectively enrolled and were compared to 10 matched PD patients without camptocormia and 12 normal controls. The normalized volumes of the brain, striatal nuclei, and the cross-sectional areas of the midbrain and pons were measured on three-dimensional magnetic resonance imaging. Data were correlated with the severity of the symptoms. The normalized axial surface of the midbrain was statistically smaller in PD patients with camptocormia than in normal controls (P = 0.01). The normalized volumetric data were not statistically different in PD patients with camptocormia. There was a significant negative correlation between the severity of camptocormia and the normalized brain volume (P < 0.009; R = −0.649) and sagittal pons area (P < 0.01; R = −0.642). The results suggest that PD with camptocormia may represent a selective form of PD in which a specific neuronal dysfunction possibly occurs within the brainstem.

Parkinson disease, brain volumes, and subthalamic nucleus stimulation

Background: High-frequency stimulation of the subthalamic nucleus (STN) is an effective treatment for advanced Parkinson disease (PD). The clinical and preoperative predictive factors of the best postoperative outcome have been identified. Radiologic predictive factors were investigated. Methods: Forty patients with PD underwent surgery for bilateral STN stimulation. MRI was performed in stereotactic conditions before surgery. Brain parenchyma, caudate nucleus, putamen, pallidum, and red nucleus volumes and the surface of the mesencephalon were measured and normalized as percentages of the intracranial volume. Clinical evaluation was performed 1 month before and 6 months after surgery. Results: The normalized brain parenchyma volume was lower in patients who were older and had a longer disease duration or a lower frontal score and was not predictive of the postoperative outcome. The residual scores for activities of daily living and parkinsonian motor disability were higher in patients with a smaller normalized mesencephalon. The normalized caudate nucleus volume was predictive of the pre- and postoperative levodopa-equivalent dosage. Conclusions: Brain atrophy is not an exclusion criterion for neurosurgery, indicating that patients’ neurologic, psychiatric, and neuropsychological characteristics are the best predictive factors for neurosurgery. The fact that a smaller normalized mesencephalon surface was associated with a lower beneficial effect of the subthalamic nucleus stimulation on the parkinsonian motor disability suggests that the normalized mesencephalon surface is a predictive factor of the postoperative outcome.

Executive dysfunction in adults with moyamoya disease is associated with increased diffusion in frontal white matter

Background and purpose Alteration of the cerebrovascular reserve (CVR) in the frontal lobes has been associated with cognitive dysfunction in adults with moyamoya disease (MMD). Elevation of the apparent diffusion coefficient (ADC) in normal-appearing white matter on conventional MRI may occur as a consequence of chronic haemodynamic failure. In the present study, the authors examined the relation of ADC with CVR and cognitive dysfunction in adults with MMD. Methods The authors measured ADC and CVR in the normal-appearing frontal white matter. CVR was calculated using dynamic susceptibility contrast-enhanced MRI and the acetazolamide challenge. A standardised and validated neuropsychological assessment test battery focusing on executive function was used. Results 14 patients, 9 women and 5 men (mean age 36.6±12.9 years), were included. The authors found executive dysfunction in 7 of 13 tested patients. ADC and CVR were negatively correlated (Spearman coefficient: −0.46; p=0.015). Elevation of ADC predicted executive dysfunction (area under receiver operating characteristic curve (95% CI): 0.85 (0.59 to 1.16); p=0.032). Conclusion Elevation of ADC in the normal-appearing frontal white matter of adults with MMD was associated with reduced CVR and executive dysfunction. This preliminary study suggests that measurement of ADC might be used to detect patients at risk for cerebral ischaemia and cognitive impairment.