Imaging of thoracic aortic injury.

Isthmic aortic rupture or disruption should be systematically sought when there is high kinetic energy trauma to the thorax. This condition is extremely serious and life threatening. It needs to be diagnosed rapidly but diagnostic pitfalls must be avoided. CT angiography is the standard examination. The main CT signs of rupture or disruption of the thoracic aorta are periaortic hematoma, intimal flap, pseudo-aneurysm and contrast agent extravasation. There are three types of lesion: intimal, subadventitial or pseudo-aneurysmal, and complete rupture with lesion of the three tunicae, and it is important to grade them for better therapeutic management. The main diagnostic pitfalls of the CT scan are the presence of a ductus diverticulum and post-isthmic fusiform dilatation. Associated lesions must not be overlooked. The most common are ruptures of the aortic root and the thoracic aorta in the diaphragmatic hiatus.

Early presentation of primary glioblastoma.

BACKGROUND: Clinical and neuroimaging findings of glioblastomas (GBM) at an early stage have rarely been described and those tumors are most probably under-diagnosed. Furthermore, their genetic alterations, to our knowledge, have never been previously reported. METHODS: We report the clinical as well as neuroimaging findings of four early cases of patients with GBM. RESULTS: In our series, early stage GBM occurred at a mean age of 57 years. All patients had seizures as their first symptom. In all early stages, MRI showed a hyperintense signal on T2-weighted sequences and an enhancement on GdE-T1WI sequences. A hyperintense signal on diffusion sequences with a low ADC value was also found. These early observed occurrences of GBM developed rapidly and presented the MRI characteristics of classic GBM within a few weeks. The GBM size was multiplied by 32 in one month. Immunohistochemical analysis indicated the de novo nature of these tumors, i.e. absence of mutant IDH1 R132H protein expression, which is a diagnostic marker of low-grade diffuse glioma and secondary GBM. CONCLUSIONS: A better knowledge of early GBM presentation would allow a more suitable management of the patients and may improve their prognosis.

[Differential diagnosis of local tumor recurrence or radionecrosis after stereotactic radiosurgery for treatment of brain metastasis]. / Diagnostic différentiel entre récidive tumorale et radionécrose après radiothérapie stéréotaxique d'une métastase cérébrale.

Magnetic resonance imaging (MRI) is a method of choice for follow-up of irradiated brain metastasis. It is difficult to differentiate local tumour recurrences from radiation induced-changes in case of suspicious contrast enhancement. New advanced MRI techniques (perfusion and spectrometry) and amino acid positron-emission tomography (PET) allow to be more accurate and could avoid a stereotactic biopsy for histological assessment, the only reliable but invasive method. We report the case of a patient who underwent surgery for a single, left frontal brain metastasis of a breast carcinoma, followed by adjuvant stereotactic radiotherapy in the operative bed. Seven months after, she presented a local change in the irradiated area on the perfusion-weighted MRI, for which the differentiation between a local tumour recurrence and radionecrosis was not possible. PET with 2-deoxy-((18)F)-fluoro-D-glucose (FDG) revealed a hypermetabolic lesion. After surgical resection, the histological assessment has mainly recovered radionecrosis with few carcinoma cells. The multimodal MRI has greatly contributed to refine the differential diagnosis between tumour recurrence and radionecrosis, which remains difficult. The FDG PET is helpful, in favour of the diagnosis of local tumour recurrence when a hypermetabolic lesion is found. Others tracers (such as carbon 11 or a fluoride isotope) deserve interest but are not available in all centres. Stereotactic biopsy should be discussed if any doubt remains.

Bilateral semicircular canal aplasia.

INTRODUCTION: Bilateral semicircular canal aplasia is extremely rare; discovery, when the cochlear-vestibular system is normal and there is no hearing loss, is serendipitous. CASE REPORT: Bilateral semicircular canal aplasia was serendipitously discovered in a 24-year-old male during assessment of unilateral mixed hearing loss with subnormal contralateral hearing. The deformity was isolated, with no associated syndrome. DISCUSSION/CONCLUSION: Incidence of this isolated entity is unknown, but doubtless greatly underestimated due to the absence of associated symptomatology. To the best of our knowledge, this is only the second report of bilateral aplasia of the entire semicircular canal system involving unilateral hearing loss. A review of the literature focuses on the embryological and molecular aspects.

[Persistent stapedial artery with otosclerosis]. / Artère stapédienne persistante et ankylose stapédovestibulaire.

OBJECTIVES: A persistent stapedial artery is a rare vascular malformation. This diagnosis is based on CT scan and intraoperative findings. MATERIAL AND METHODS: The case of a 19-year-old woman with a persistent stapedial artery found during stapes surgery is reported. This vascular malformation was explored with a CT scan showing the bilaterality of this anatomical variation and signs of associated otosclerosis. RESULTS: This malformation was successfully coagulated with laser allowing the stapedotomy to be completed. CONCLUSIONS: A persistent stapedial artery is not a contraindication to stapedotomy because it can be safely coagulated during the same procedure.

An autopsy case of acute multiple sclerosis (Marburg's type) during pregnancy.

We report a case of a 9-month pregnant woman who presented acute psychiatric and neurological symptoms with extensive involvement of the white matter on MRI and no oligoclonal bands on CSF examination. Despite high doses of intravenous steroids, plasmapheresis and immunosuppressive drugs, a fatal outcome (coma) was noted 8 months later. Neuropathological examination confirmed the diagnosis of Marburg's type of multiple sclerosis showing sharp-edged lesions of demyelination, giant astrocytes, numerous macrophages and little perivascular inflammation. We discuss the definition and limits of the Marburg entity with reference to acute disseminated encephalomyelitis, impact of pregnancy, unusual MRI features, neuropathology and treatment.

[Conventional and diffusion magnetic resonance imaging in the acute phase of severe traumatic brain injury]. / Apports de l'IRM conventionnelle et de l'IRM de diffusion à la phase aiguë du traumatisme crânien grave.

Neuro-imaging is essential for the initial evaluation and subsequent control in the acute stage of severe head injury. In these indications tomodensitometry (TDM) has a pivotal role. Despite the well recognized contribution of magnetic resonance imaging (MRI) to the investigation of most of acute neurological pathologies, MRI is not still a routine procedure for the initial investigation of patients with acute head injury. The superiority of morphological and functional MRI on TDM in this indication is discussed.

Persistent carotid-vertebrobasilar anastomoses: how and why differentiating them?

The persistent carotid-vertebrobasilar anastomoses (PCVBA) can be explained by an interruption of the vertebrobasilar system (VBS) embryogenesis. We present two very rare cases of persistent anastomoses: a hypoglossal artery and a type I proatlantal artery, insisting on the angiographic criteria allowing differentiation. After a brief review of the embryogenesis of the VBS, we describe the different types of persistent anastomoses (hypoglossal, type I and II proatlantal, trigeminal and otic arteries). We will insist on the potential risks, not well-known, but typical of each anastomosis. PCVBA usually are incidental findings but imaging follow-up may be required since aneurysms may develop.

Radio-anatomic study of the pancreatic duct by MR cholangiopancreatography.

To compare the performance of MR-cholangiopancreatography (MRCP) and that of classical anatomy in the depiction of the main pancreatic duct, 50 MRCP examinations were done in patients free of pancreatic disease. Axial and coronal sections 20 mm thick were obtained in a Single Shot Fast Spin Echo (SSFSE) sequence. The following were analyzed: (1) visibility of pancreatic duct structures, (2) form of the main pancreatic duct, (3) various angulations of the duct and (4) diameter of the duct. Anatomic variants were noted. These findings were compared with anatomic and radio-anatomic (ERCP) data in the literature. The main pancreatic duct was visualized in 100% of cases and the accessory pancreatic duct in 61%. The form, diameter and angulations of the various segments of the pancreatic duct were similar to those reported in the literature. These findings are reported in the axial and coronal planes. Comparison with major anatomic classifications was not possible. MRCP enables in vivo anatomic exploration of the main pancreatic duct. Horizontal sections provided new radio-anatomic information. The technique nevertheless remains limited by poor spatial resolution.

Use of half-dose gadolinium-enhanced MRI and magnetization transfer saturation in brain tumors.

The aim of this study was to search if half-dose gadolinium (Gd)-enhanced MR imaging with magnetization transfer saturation (MT) can replace standard-dose T1-weighted spin echo (SE) without MT saturation in brain tumors. Thirty patients with a total of 33 brain tumors (14 gliomas, 13 meningiomas, 6 metastases) were prospectively studied using T1-weighted SE half-dose of Gd with MT, and T1-weighted SE standard-dose Gd without MT. The contrast-to-noise ratio (CNR) of the two sequences was calculated and four radiologists reviewed qualitatively the images of the two sequences. There was no significant difference between both techniques for quantitative analysis (Wilcoxon test). However, there was a good agreement between sequences to evidence an intraclass correlation coefficient (r = 0.70) of all lesions. In cases of meningioma, the agreement was better (r = 0.84). The results show a difference in the qualitative data between the two sequences, suggesting the use of the T1-weighted MR images with MT and half-dose of Gd with good results in the whole tested parameters except the lesional edema and the presence of artifacts. Half-dose T1-weighted SE with MT can replace standard-dose T1-weighted SE without MT with no loss of contrast enhancement in investigation of meningiomas and saving 50% of the contrast material.

Anatomic and radioanatomic study of the lateral genicular arteries: application to prevention of postoperative hemarthrosis after arthroscopic lateral retinacular release.

Arthroscopic lateral retinacular release can be complicated by hemarthrosis in 10 to 18% of cases. The vascular structures involved are the lateral vascular pedicles of the knee. This study examines the topography of these pedicles. Anatomic and radioanatomic studies carried out in 50 specimens defined the route of the vascular pedicles at the lateral aspect of the knee. From the measurements carried out, we noted the relative homogeneity of the routes taken by the different proximo-lateral vascular pedicles, which are highly vulnerable, and the variability of the disto-lateral arterial routes. A tracing-paper study identified two distinct routes for the disto-lateral vascular pedicle and evaluated the risk of injury to it in surgical approaches to the lateral aspect of the knee. Finally, the topographic data of the study suggest the possibility of preventive hemostasis of the proximo-lateral pedicle via a minimal approach close to the patella. Furthermore, it seems possible to avoid cutting the disto-lateral pedicle if it is localised by cutaneous trans-illumination at the beginning of the operation.

Ultrasonographic diagnosis of hepatic fibrosis or cirrhosis.

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.

[Cervical deficit radiculopathy in 3 cases of vertebral artery dissection]. / Radiculopathie cervicale déficitaire au cours de trois cas de dissection de l'artère vertébrale.

Three cases of extracranial vertebral artery dissections with upper limb peripheral motor deficit (C5-C6) are reported. Six similar cases were also found in the literature. Central neurological symptoms occurred in five of these nine cases, suggesting the diagnosis of dissection. The peripheral motor or sensorial deficit was strictly isolated in the four other cases, simulating radicular neuralgia due to discopathy or foraminal compression. In case of dissections, a precise analysis of pain is helpful to guide diagnosis; sharp, unbearable, continuous and extended neck pain without nocturnal paroxysms and posterior neck stiffness is typical. Analgesics or anti-inflammatory drugs are ineffective. Peripheral motor deficit is more common than sensory deficit. Recovery was complete in this series. In most cases, the radiculopathy appears to be due to cervical root compression in its extraforaminal course due to the dissection hematoma and rarely to radicular ischemia.