Influence of age on the dynamics of fMRI activations during a semantic fluency task.

PURPOSE: Age-related fMRI changes have not been extensively studied for language, whereas important adaptive mechanisms have been seen in other cognitive fields. This study examined age-related changes in fMRI activation during language tasks and, in particular, their dynamic course. PATIENTS AND METHODS: fMRI was performed on 22 young and 21 old healthy right-handed subjects during a silent category word-generation task. Activation and dynamics of BOLD signals were studied separately during the first and second portions of each 30-s block. RESULTS: Activation of the left frontal lobe was initially similar in young and old participants; however, it decreased after 30 s in the old participants. On the other hand, additional areas were initially involved only in old subjects and especially in the default mode network. CONCLUSION: This study showed age-related differences in the dynamics of fMRI activation during a silent word-generation task, suggesting a different pattern of language function with aging.

Intracranial primary synovial sarcoma mimicking a spontaneous cerebral hematoma-a case report and review of the literature.

BACKGROUND: Synovial sarcoma is a soft tissue sarcoma, of uncertain histological origin, usually located near large joints and concerning mainly young adults. Intracranial presentation in the form of metastasis from a primitive body sarcoma has been rarely reported. However, intracranial primitive synovial sarcoma (IPSS) is extremely rare and only a few cases have been reported in the literature. CASE DESCRIPTION: We present the case of a 48-year-old man, with no particular medical history, that was referred to our hospital for severe headache with a normal neurological exam and a CT cerebral scan showing a left frontal lobe hematoma. The initial cerebral CT scan didn't show any vascular malformation and the body CT scan was negative for a primitive lesion. A close follow-up with a cerebral MRI three months later, demonstrated a T1 enhanced lesion with an important volume progression. The patient underwent a complete surgical removal of this lesion and the first pathology diagnosis was compatible with a meningioma. After further proofreading by an expert and molecular analysis, the diagnosis of monophasic synovial sarcoma was confirmed. Nine months after the first surgery, the follow-up MRI showed the progressive recurrence of the lesion and in this context the patient underwent a second surgery with total resection of the tumor and frontal thin margin excision. Afterwards, the patient was treated with adjuvant radiotherapy, with a good clinical evolution, and till now the follow-up shows no recurrence. CONCLUSION: IPSS is an extremely rare sarcoma, with challenging diagnosis and difficult management. Specific molecular analysis is necessary. Complete resection followed by radiotherapy seem to be the most appropriate therapeutic approach. However, the prognosis is still poor. Our case is even rarer because of the initial presentation as a cerebral hematoma.

[Spasmodic torticollis caused by metoclopramide: a rare etiology of C1-C2 rotatory pseudoluxation in children]. / Un torticolis spasmodique lié à la prise de métoclopramide: une cause rare de pseudoluxation rotatoire C1-C2 chez l'enfant.

Torticollis in children must always instigate a search for trauma. Many other etiologies can be found. The authors report a case of postmedicinal atlantoaxial rotatory pseudoluxation (AARP) occurring in a child. This child had fallen down in the morning with head trauma followed by headache. Clinically, a stiff neck with an irreducible right rotation of his neck, and an osteotendinous hyperreflexia were noted. There was a C1-C2 rotatory dislocation with no traumatic lesion on the cervical CT scan. After a few hours, the torticollis spontaneously reduced and then reappeared on the left side. This clinical fluctuation and the absorption of metoclopramide (Primpéran) started in the morning for acute gastroenteritis provided the diagnosis of AARP. This entity was confirmed by the good clinical and radiological follow-up and was caused by the substantial ligament laxity of the craniovertebral junction encountered in children. The analysis of medical imaging and the systematic search for a medicinal cause helped make the right diagnosis.

[Abnormal features of the sub renal portion of the inferior vena cava]. / Anomalies de la veine cave inférieure sous rénale.

AIM: to determine the frequency of the abnormal anatomical features affecting the inferior vena cava (IVC). MATERIAL AND METHODS: we performed 161 dissections of the ICV on fresh (145) or formaldehyde-injected (16) cadavers. There were 86 men and 75 women. RESULTS: we found two abnormalities of the IVC: one left IVC in a woman and one double IVC in a man. These malformations can be explained by the embryology of the IVC. DISCUSSION: the frequency of abnormalities of the IVC is highly variable according to the studies: Richardson (1983) found 3% for the duplication of the IVC. Other malformations have been reported: double IVC, left IVC or right IVC with azygos prolongation. We never observed such associations in our study. Left IVC could be explained by the development of the left supra-cardinal vein and by that of the left sub-cardinal and intercardinal anastomoses. Double IVC corresponds either to the development of the left supra-cardinal vein or to the persistence of the left cardinal vein or the left sub-cardinal vein. CONCLUSION: abnormalities of the ICV dysplay different anatomical features due to the complexity of the embryogenesis of this vessel; their frequency is far from being rare. Unknowing these abnormalities could lead to severe haemorrhages during surgical interventions on the retroperitoneal, cardiac or oesophageal regions.

[Duplication of the inferior vena cava: anatomical dissection and clinical implications]. / Dédoublement de la veine cave inférieure: dissection anatomique et applications cliniques.

The duplication of the inferior vena cava is often incidentally discovered during radiological studies. The presence of this anomaly can be mistaken for retroperitoneal adenopathy. Its knowledge allows to avoid hemorrhagic complications during retroperitoneal surgery. An anatomical dissection of a duplication of the inferior vena cava is presented. Embryogenesis and variations are described. Radiological and clinical implications are discussed.

From Vesalius to tractography.

The description of an anatomical specimen may look straightforward, but it appears that it depends in fact on several intermingled factors: technical methods for conservation, dissection and vascular injection and the anatomist skills are of course important. This is especially true when the studied organ, as for instance the brain, is subject to rapid putrefaction after death without any preservation technique. Nevertheless the possibility to reject, or at least criticize, the dominant paradigm is probably as important as these technical considerations: important changes occurred in brain representation between the early Middle Ages and the Early Modern Times, without major improvements of cadaveric preservation or dissection methods; Vesalius rejected the existence of the rete mirabile in human not only because he was a talented anatomist but also because he accepted and had the courage to fight the dominant tradition inherited from Galen. Such difficulties in the scientific approach obviously remain vivid, and should not be forgotten despite the development of modern tools for studying brain morphology and function.

[Predictive factors for visual outcome after corneal collagen crosslinking treatment in progressive keratoconus: One-year refractive and topographic results]. / Facteurs prédictifs de bonne réponse au crosslinking d'un kératocône évolutif : résultats réfractifs et topographiques à un an postopératoire.

PURPOSE: To assess the effects of preoperative patient characteristics on clinical outcomes of corneal collagen crosslinking (CXL) in patients with progressive keratoconus. PATIENTS AND METHODS: Fifty-four eyes of 41 patients underwent CXL for progressive keratoconus between June 2011 and December 2012. Corneal topography (Orbscan(®)) was assessed at 1, 3, and 6 months and 1 year after CXL treatment and compared with preoperative data. RESULTS: A significant improvement in 1-year postoperative best-corrected visual acuity (BCVA) (0.16±0.21 LogMar preoperatively versus 0.09±0.16 LogMar postoperatively, P=0.007) and in 3mm topographic central irregular astigmatism (P=0.04) was demonstrated with CXL. No significant change was noted for refractive astigmatism (P=0.69), or for 1-year postoperative Kmax (48.4 D±4.1 at baseline versus 48.5 D±4.1 postoperatively, P=0.46). Predictive factors for BVCA improvement were low preoperative BCVA, high refractive astigmatism and advanced keratoconus. Predictive factors for stability of postoperative Kmax values were early keratoconus, and central cone ("nipple" morphology of the cone mainly located in the central 3mm of the cornea). CONCLUSION: This retrospective study confirms the efficacy of CXL for progressive keratoconus, from a refractive as well as topographic standpoint. While cone localization or its eccentricity seems to explain the variability of CXL efficacy reported in the literature, cone severity appears to be the main predictive factor for a lack of topographic stability after CXL treatment but must be weighted by the preferential localization of the cone (3 or 5mm central corneal zone).

Fronto-orbital sphenoidal fibrous dysplasia.

We report the clinical, radiological, and histological features of an 8-year-old boy with an unusual presentation of fronto-orbital sphenoidal fibrous dysplasia. The various forms of fibrous dysplasia are outlined and the differential diagnosis discussed. An approach to surgical management is proposed.

Microanatomy of the pericallosal arterial complex.

OBJECT: The pericallosal arterial complex supplies the callosal and pericallosal regions, as well as the anterior two thirds of the medial and superomedial aspects of both hemispheres. It is composed of the pericallosal artery (that is, the segment of the anterior cerebral artery located distal to the anterior communicating artery [ACoA]) and the median callosal artery (or third pericallosal artery), which originates from the ACoA. This system was studied in 46 specimens (23 human cadaver heads) injected with colored latex. METHODS: After being injected with colored latex, embalmed, and bleached, the specimens were studied with the aid of optic magnification. The pericallosal artery was found to be divided into four segments (A2-A5 in the proximodistal direction). After giving rise to central, callosal, and cortical branches, it terminated near the splenium of the corpus callosum as the posterior pericallosal artery, or on the precuneus as the inferomedial parietal artery. CONCLUSIONS: The authors propose a logical classification of the different variations in the pericallosal arterial complex based on embryological development. This complex can be considered a hemodynamic solution to an abnormal regression of one of its parts, which is balanced by the development of supplemental channels from other parts.

Microanatomy of the hypophyseal fossa boundaries.

OBJECT: The authors studied the heads of 17 adult cadavers and one fetus to clarify the anatomy of the sellar region, particularly the lateral boundaries of the hypophyseal fossa. METHODS: Vascular injections and microdissection or histological techniques were used in this study. The roof of the cavernous sinuses and diaphragma sellae were part of a single horizontal dural layer that joined the two anterior petroclinoid folds. Laterally, the direction of this layer changed; it became the lateral wall of the cavernous sinus and joined the dura mater of the middle cerebral fossa. On the midline, this layer ballooned toward the sella through the diaphragmatic foramina, created a dural bag containing the hypophysis, and attached to the inferior aspect of the diaphragma sellae. As a consequence, no straight sagittal dural wall existed between the pituitary gland and cavernous sinus; the lateral border of the hypophyseal fossa was part of this anteroposterior and superoinferior convex bag. The authors stress the importance of the venous elements of the region and discuss the structure of the cavernous and coronary sinuses. CONCLUSIONS: Invasion of the cavernous sinus makes surgery more risky and difficult and may necessitate modification of the surgical treatment plan. The preoperative diagnosis of cavernous sinus invasion is thus of great interest, but the possibility of normal lateral expansions of the pituitary gland must be kept in mind. A lateral expansion of this gland into the cavernous sinus was encountered in 29% of the specimens, and an adenoma that developed in such an expansion could easily mimic cavernous sinus invasion.

A new concept in Dorello's canal microanatomy: the petroclival venous confluence.

The so-called Dorello's canal was studied in 32 specimens (16 human cadaver heads) injected with colored latex and fixed in formalin (28 specimens) or studied with microscopic and ultrastructural methods (four specimens). To avoid the differences usually encountered in the description of this area, the authors preferred to consider a larger space that they have named the petroclival venous confluence (PVC). It was located between two dural layers: inner (or cerebral) and outer (or osteoperiosteal). The PVC was quadrangular on transverse section. The posterior petroclinoid fold and the axial plane below the dural foramen of the abducent nerve (sixth cranial nerve) limited the PVC at the top and bottom, respectively. Its anteroinferior limit was the posterosuperior aspect of the upper clivus and outer layer of the dura mater. Its anterior limit was the vertical plane containing the posterior petroclinoid fold, and its posterior limit was the inner layer of the dura. The PVC was limited laterally by the medial aspect of the petrous bone apex and medially by the virtual sagittal plane extending the medial limit of the inferior petrosal sinus upward. The PVC was a venous space bordered by endothelium and continuous with the cavernous sinus, the basal sinus of the clivus, and the inferior petrosal sinus. There were trabeculations between the two dural layers. The petrosphenoidal ligament of Gruber may be regarded as a larger trabeculation, and it divided the PVC into a superior and an inferior compartment. The abducent nerve generally ran through the inferior compartment, where it was fixed to the surrounding dura mater. This nerve was only separated from venous blood by a meningeal sheath of varying thinness lined with endothelium. The clinical implications of these findings are discussed.

[Role of high-dose chemotherapy with hemopoietic stem-cell support in the treatment of adult patients with high-grade glioma]. / Place de la chimiothérapie intensive avec autogreffe de cellules souches hématopoïétiques dans le traitement des tumeurs gliales de haut grade chez l'adulte.

Despite surgery, post-operative irradiation and adjuvant conventional chemotherapy, prognosis of high-grade gliomas remains poor. Carmustine (BCNU) has been shown to have limited activity at conventional dosage but is still the standard chemotherapy. Activity of chemotherapy is limited by the blood-brain barrier impermeability and high levels of expression of multidrug resistance proteins on tumor and/or endothelial cells. Despite high response rates, development of intra-arterial chemotherapy remains limited because of frequent acute brain toxicity related to drug administration. High-dose intravenous chemotherapy rescued by autologous hemopoietic stem cell transplantation is an alternative that might increase drug delivery through the blood-brain barrier and tumor control. Several phase I-II trials using high-dose BCNU were published. The maximum tolerated dose seems to be 800 mg/m2 and interstitial pneumonitis and hepatitis are dose-limiting toxicities. Few phase I-II trials of high-dose therapy were published using drug combinations. High response rates in patients with progressive tumor were observed and in adjuvant setting, encouraging results in terms of median survival time and long survivors were published. No phase III trial was reported to date. Future investigations should include randomized trials comparing high-dose and conventional-dose chemotherapy and development of new high-dose regimens that incorporate new drugs such as temozolomide.

[MRI diagnosis of sinus cavernous invasion by pituitary adenomas]. / Diagnostic en IRM de l'envahissement du sinus caverneux par les adénomes hypophysaires.

PURPOSE: To evaluate the preoperative MRI criteria of a sinus cavernous invasion by a pituitary adenoma. MATERIAL AND METHODS: Study of 102 cavernous sinuses among 51 patients who had had a surgical cure of pituitary adenoma. Thirteen patients had a surgical invasion of the cavernous sinus. RESULTS: A certain number of signs eliminated cavernous sinus invasion. The best means consisted in not crossing the intercarotid line (Sensitivity-Se = 100%, Specificity-Sp = 85% and Negative Predictive Value-NPV = 100%). The others means implied: not going past twelve o'clock on the internal carotid artery-ICA (NPV = 97.1%), symmetrical size of the cavernous sinus (NPV = 92.5%), non-convexity of the lateral wall (NPV = 90.2%), visualization of at least two venous groups of the laterosellar space (NPV = 90.2%) and finally, non-displacement of the ICA (NPV = 89.2%). The best criteria for diagnosis were passing by the intra and supracavernous ICA lateral tangent (Se = 84.6%, Sp = 95%) and the percentage of ICA encasement by the adenoma exceeding 25% (Se = 92.3%, Sp = 85%). CONCLUSION: Except the total encasement of the intracavernous ICA, the cavernous sinus can be invaded when the lateral tangent of the supra and the intracavernous ICA is crossed, and also when the percentage of ICA encasement exceeds 25%.

[MRI diagnosis of cavernous sinus invasion by pituitary adenomas]. / Etude IRM de l'invasion des sinus caverneux par les adénomes hypophysaires.

Several MRI signs are helpful for the preoperative MRI diagnosis of cavernous sinus invasion by an adenoma. The first step is to analyse the percentage of encasement of the intracavernous ICA by the adenoma. If this percentage is greater than or equal to 66%, the cavernous sinus is invaded. If the percentage of encasement of intracavernous CA is less than 25%, the cavernous sinus is not invaded. If the percentage of encasement is between 25 and 66%, the analysis of the cavernous venous compartment, the drawing of intercarotid lines and the analysis of the shape and venous compartments of the cavernous sinus are necessary. The cavernous sinus invasion remains very likely if the carotid sulcus venous compartment is obliterated, or if the lateral intercarotid line is crossed. Conversely, if the median intercarotid line is uncrossed, the superior venous compartment is visible, the cavernous sinus is of normal size, or there is no bulging of its lateral dural wall, invasion of the cavernous sinus space can reliably be excluded.

[Intracavernous invagination of pituitary macro-adenomas]. / L'invagination intra-caverneuse des macro-adénomes hypophysaires.

Depending on authors, intra-cavernous invasion by a pituitary adenoma is found in 9% to 40% of cases. In the light of our own experience, we think that such an invasion is probably much less frequent than usually evoked on CT-scan and MRI. In our study, it was confirmed in only one case over 125 (0.80%), though radiological data suspected an intra-cavernous invasion 17 times. An anatomical study on 20 cadavers showed that 30% of normal pituitary glands present with a lateral expansion into one or both cavernous sinuses (CS). These natural invaginations were already evoked by Harris and Rhoton in 1976. They can resemble an intra-cavernous extension or invasion on MRI views, moreover when an adenoma increases the volume of this expansion, and in the absence of any rupture of the medial wall of the CS. The medial wall of the CS is, in fact, constituted by a dural pouch which close-fits the pituitary gland and its expansions; it invaginates more or less in the CS, depending on the importance of the pituitary lateral expansion. In case of a large adenoma, the finger-glove lateral distension of the pouch disappears progressively during the tumoral removal. Finally the dura returns to its normal place back, at the end of the procedure. This concept of invagination of the CS medial wall, as opposed to that of invasion and therefore of rupture of the dural plane, explains the wide range of figures concerning the frequency of intracavernous invasion by pituitary adenomas, in the literature. These figures are all the more variable as there is no absolute criteria of intra-cavernous invasion on CT-scan nor MRI views. In the same way, no clinical criteria can be retained to assume the existence of such an invasion. So, an ophthalmoplegia seems to be usually linked to a compression of occulomotors nerves; it recovers in a large majority of cases, after the adenoma is removed. In conclusion we emphasize the necessity of interpreting with great care radiological imaging when it evokes' a possible intra-cavernous invasion of a pituitary adenoma. The indication of an eventual radiotherapy should be retained with as much care as possible, since complete removal of an adenoma and its lateral expansion(s) is almost always feasible through a trans-sphenoidal route.

[Pituitary disorders in pregnancy]. / Pathologie hypophysaire et grossesse.

During pregnancy there is a normal increase in the volume of the anterior pituitary as demonstrated by MRI and hormone secretions which increase (PRL) or decrease (FSH, LH). During pregnancy pituitary adenomas, especially prolactinomas, may evolve as in non-pregnant women (microadenomas) or differently (macroadenomas). In 35 % of cases macroprolactinomas worsen during pregnancy making their medico-surgical management mandatory prior to pregnancy. Inversely, pregnancy occurring in a subject with a microprolactinoma never induces severe local complications so such tumors may be managed surgically or medically. Surgery should be performed for acromegaly or Cushing's disease before or early in pregnancy. Subacute pituitary apoplexy (intratumoral hemorrhage) occurs in about 10 to 15 % of adenomas but, generally speaking, clinical symptoms remain mild in pregnant women. Lymphocytic hypophysitis occurs at the end of pregnancy, or during the post-partum period. The association of complete pan-hypopituitarism and hypersignal on MRI examination may mimic hypophyseal apoplexy and could lead to and inappropriate surgical procedure.

[Development of the corpus callosum (CC)]. / Développement du corps calleux.

Corpus callosum embryology can be divided into three parts: during "commissuration", a cellular mass develops between the two telencephalic vesicles. The primitive lamina terminalis corresponds to the closing point of the anterior neuropore. Its dorsal part grows and forms the lamina reunions (6-8 intra uterine weeks, IUW). From ventral to dorsal, this lamina reunions gives rise to the area praecommissuralis (origin of the anterior commissure), to the primordium hippocampi (10 I.U.W., fornix), and to the massa commissuralis (10 S.I.U., corpus callosum). Fibers arising from the developing hemispheres run through this primitive corpus callosum. The growth of the corpus callosum follows the expansion of the hemispheres, in a rostro-caudal and then dorso-ventral circular movement. The last part of the corpus callosum to form is the rostrum. Maturation occurs postnatally, and corresponds to axonal elimination, and myelination, progressively changing the callosal connection pattern of the newborn and infant into the adult pattern.

[Morphologic anatomy of the corpus callosum]. / Anatomie morphologique du corps calleux.

The corpus callosum is a neopallial commissure. In inferior vertebrates, the pallial commissures are essentially represented by the anterior commissure. The corpus callosum appears in mammals only. Eutherians alone have a corpus callosum, the other mammals have an anterior commissure and hipocampal commissure. In humans, the different portions of the corps callosum are described on a median sagittal slice: rostrum, genu, body, isthmus, splenium. Klingler method allows to dissect fibers of each of these portions and their relationship with the corona radiata and optic radiations. These latter are separated from the ventricular ependyme by callosal radiations. Finally, each part of the corpus callosum participates in lateral ventricle wall formation.

[Arterial and venous vascularization of the corpus callosum]. / Vascularisation artérielle et veineuse du corps calleux.

Blood supply of the corpus callosum is assured by two arterial systems, the carotid system mainly and the vertebrobasilar system accessorily. The carotid system intervenes via the pericallosal artery, portion of the anterior cerebral artery distal to the anterior communicating artery. This pericallosal artery can be bihemispheric in 4 to 12% of the cases or azygos in 0.26% of cases. In 20 to 80% of cases, the median callosal artery arises from the communicating artery. The vertebrobasilar system intervenes in splenium vascularization by its terminal branches. These two carotid and vertebrobasilar systems give rise to perforating arteries that assure intrinsic vascularization of the corpus callosum creating a system of regular vascular stitches around the fibers of the corpus callosum. The venous drainage of the corpus callosum is essentially via callosal veins and callosocingulate veins towards the deep venous system of the brain.