Jean-François Bonneville

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.

Free-floating thrombus of the extracranial internal carotid artery.

Free-floating clots of the extracranial internal carotid artery are generally considered as surgical emergencies. This retrospective study analyzes six free-floating clots diagnosed by arteriography. Three of these patients had a fixed stroke while the other three had an evolving stroke. Three patients had antecedent ocular or hemispheric transient ischemic attacks. The causes of free-floating clots in the internal carotid artery were atheromatous stenosis in two cases, ulcerated plaque in three cases, and carotid artery dissection in one. All six patients were seen late, approximately 15 hours after their neurologic accident. They were treated with intravenous heparin over a two to five week period. Repeat arteriograms demonstrated complete clot lysis in four instances, while partial lysis was seen in one case. Moderate extension of thrombus occurred in one case only. No further neurologic complications were noted during the treatment by heparin. As indicated by follow-up arteriographic findings, secondary surgery was performed for major carotid lesions and residual clots in five cases. The free-floating thrombus syndrome of the carotid artery should not be considered as a surgical emergency when discovered late in the wake of an acute neurologic accident.

Computed tomography of the pituitary gland

This book is written entirely to include the imaging of the pituitary gland by computed tomography (CT). The first three chapters illustrated technical aspects of scanning, anatomic depiction of the gland by CT, and the use of dynamic CT scanning for detecting and displaying abnormalities. The chapters discuss and illustrate various types of pathologic processes in and around the pituitary gland. One short but very helpful chapter demonstrates potential pitfalls due to the combination of anatomic variants and the geometry of CT sections. Some illustrations of disease processed are depicted by magnetic resonance imaging. All major types of pituitary diseases are illustrated. Lists of readily available English-language references are available. A small subject index is provided at the end of the book in which the illustrations are identified by use of a special numeric front.

Pituitary MRI characteristics in 297 acromegaly patients based on T2-weighted sequences

Responses of GH-secreting adenomas to multimodal management of acromegaly vary widely between patients. Understanding the behavioral patterns of GH-secreting adenomas by identifying factors predictive of their evolution is a research priority. The aim of this study was to clarify the relationship between the T2-weighted adenoma signal on diagnostic magnetic resonance imaging (MRI) in acromegaly and clinical and biological features at diagnosis. An international, multicenter, retrospective analysis was performed using a large population of 297 acromegalic patients recently diagnosed with available diagnostic MRI evaluations. The study was conducted at ten endocrine tertiary referral centers. Clinical and biochemical characteristics, and MRI signal findings were evaluated. T2-hypointense adenomas represented 52.9% of the series, were smaller than their T2-hyperintense and isointense counterparts (P<0.0001), were associated with higher IGF1 levels (P=0.0001), invaded the cavernous sinus less frequently (P=0.0002), and rarely caused optic chiasm compression (P<0.0001). Acromegalic men tended to be younger at diagnosis than women (P=0.067) and presented higher IGF1 values (P=0.01). Although in total, adenomas had a predominantly inferior extension in 45.8% of cases, in men this was more frequent (P<0.0001), whereas in women optic chiasm compression of macroadenomas occurred more often (P=0.0067). Most adenomas (45.1%) measured between 11 and 20 mm in maximal diameter and bigger adenomas were diagnosed at younger ages (P=0.0001). The T2-weighted signal differentiates GH-secreting adenomas into subgroups with particular behaviors. This raises the question of whether the T2-weighted signal could represent a factor in the classification of acromegalic patients in future studies.

Post-surgical management of non-functioning pituitary adenoma.

Post-surgical surveillance of non-functioning pituitary adenoma (NFPA) is based on magnetic resonance imaging (MRI) at 3 or 6 months then 1 year. When there is no adenomatous residue, annual surveillance is recommended for 5 years and then at 7, 10 and 15 years. In case of residue or doubtful MRI, prolonged annual surveillance monitors any progression. Reintervention is indicated if complete residue resection is feasible, or for symptomatic optic pathway compression, to create a safety margin between the tumor and the optic pathways ahead of complementary radiation therapy (RT), or in case of post-RT progression. In case of residue, unless the tumor displays elevated growth potential, it is usually recommended to postpone RT until progression is manifest, as efficacy is comparable whether treatment is immediate or postponed. The efficacy of the various RT techniques in terms of tumor volume control is likewise comparable. RT-induced hypopituitarism is frequent, whatever the technique. The choice thus depends basically on residue characteristics: size, delineation, and proximity to neighboring radiation-sensitive structures. Reduced rates of vascular complications and secondary brain tumor can be hoped for with one-dose or hypofractionated stereotactic RT, but there has been insufficient follow-up to provide evidence. Somatostatin analogs and dopaminergic agonists have yet to demonstrate sufficient efficacy. Temozolomide is an option in aggressive NFPA resistant to surgery and RT.

Cerebral Aneurysms in a Patient with Osteogenesis Imperfecta and Exon 28 Polymorphism of COL1A2

Osteogenesis imperfecta (OI) is a heterogeneous group of heritable disorders characterized by increased bone fragility. Typical extraskeletal manifestations (hearing loss, blue sclerae, dentinogenesis imperfecta, and hyperlaxity of ligaments and skin) can be variably associated, but no agreed

Extraforaminal lumbar disc herniations: CT demonstration of Sharpey's fibers avulsion

SummaryForty-seven extraforaminal lumbar disc herniations (EFLDH) accounting for 7% of all lumbar disc herniations encountered during the same period of time were reviewed. L3–L4 or L4–L5 disc was involved in 89% of the cases giving rise to a L3 or L4 nerve root compression. An abnormal motion of lateral bending with rotation of the trunk was found retrospectively in 60% of the patients. In 53% of all EFLDH a bony avulsion of the vertebral endplante facing the herniation was demonstrated at the site of attachment of Sharpeys fibers. This study suggests that this previously undescribed bony change witnesses a special injury of the spine responsible for most EFLDH.

Dural enhancement in pituitary macroadenomas

Abstract We describe the normal dural enhancement patterns of the sellar region and determine whether the duramater is affected by pituitary macroadenomas. Dural enhancement appeared to be usually abnormal in 20 patients with pituitary macroadenoma compared with 20 control patients, mainly at the planum sphenoidale and carotid sulcus. However dural changes are subtle and their recognition requires knowledge of the normal enhancement patterns. Dural changes, reported in a variety of inflammatory and infectious dural diseases and after surgery, are not specific and may be also seen in pituitary macroadenomas.

CT follow-up of microprolactinomas during bromocriptine-induced pregnancy

SummaryIn the last few years complete or partial regression of prolactinomas has been demonstrated in nonpregnant women treated by bromocriptine. Thus bromocriptine therapy appears as an attractive alternative to surgery for management of infertility related to hyperprolactinemia. However, numerous reports emphasized the possibility of an excessive growth of the pituitary adenoma with visual field defects during the last 3 months of pregnancy. To avoid these complications, the authors followed with serial CT scans the growth of microprolactinoma at the 5th or 6th month of pregnancy. Among six pregnant women, one patient presented a marked upward extension of the adenoma. Bromocriptine was then reintroduced and the effectiveness in reducing tumor growth was proved by CT scan at the 7th month. Regarding low risk of using intravenous iodinated contrast medium in pregnant women and of fetal radiation damage, the authors emphasize the value of CT in the follow-up of bromocriptine-induced pregnancies.

Imagerie des adénomes hypophysaires

In cases of pituitary hormone hypersecretion, magnetic resonance imaging (MRI) can demonstrate the causal lesion, which is often small (microadenoma). In pituitary adenomas with suprasellar extension, MRI shows the tumors relation to the surrounding structures: the optic chiasm, the internal carotid artery, the sphenoidal sinus, etc. MRI usually makes it possible confirm or rule out any cavernous sinus invasion by the pituitary adenoma, a determination essential for planning treatment. After pituitary surgery, MR imaging is again essential for visualizing any residual tumor tissue and - if the MRI is carefully performed to be reproducible - for assessing its development over time.