A test of the lateral semicircular canal correlation to head posture, diet and other biological traits in "ungulate" mammals.

For over a century, researchers have assumed that the plane of the lateral semicircular canal of the inner ear lies parallel to the horizon when the head is at rest, and used this assumption to reconstruct head posture in extinct species. Although this hypothesis has been repeatedly questioned, it has never been tested on a large sample size and at a broad taxonomic scale in mammals. This study presents a comprehensive test of this hypothesis in over one hundred "ungulate" species. Using CT scanning and manual segmentation, the orientation of the skull was reconstructed as if the lateral semicircular canal of the bony labyrinth was aligned horizontally. This reconstructed cranial orientation was statistically compared to the actual head posture of the corresponding species using a dataset of 10,000 photographs and phylogenetic regression analysis. A statistically significant correlation between the reconstructed cranial orientation and head posture is found, although the plane of the lateral semicircular canal departs significantly from horizontal. We thus caution against the use of the lateral semicircular canal as a proxy to infer precisely the horizontal plane on dry skulls and in extinct species. Diet (browsing or grazing) and head-butting behaviour are significantly correlated to the orientation of the lateral semicircular canal, but not to the actual head posture. Head posture and the orientation of the lateral semicircular canal are both strongly correlated with phylogenetic history.

Infection of the right iliac fossa.

Febrile pain in the right iliac fossa is one of the most common reasons for consulting at an emergency service. Within this framework, the main diagnosis that is considered is appendicitis, the main complication of which is perforation. However, a certain number of other conditions can be responsible for this clinical picture, primarily including digestive tract and mesentery disorders including mesenteric lymphadenitis, Crohn's disease, infectious enterocolitis, small intestine or colonic diverticulitis, ischaemic colitis or cancer of the caecum. This article illustrates the imaging semiology of the various right colonic, iliac, mesenteric and appendicular conditions that could potentially cause an infection of the right iliac fossa. It specifies the indications of ultrasound and CT scans, respectively, which depend on the age of the patient and the clinical signs and symptoms. Though the CT scan is commonly used in abdominal emergencies in general, and particularly in clinical pictures of infection of the right iliac fossa, ultrasound remains recommended as first line imaging when confronted with suspected appendicitis or lymphadenitis in a young subject or in the monitoring of Crohn's disease.

Pearls and pitfalls in breast MRI.

At our academic institution, we have noticed repeated examples of both false-positive and false-negative MR diagnoses in breast cancer. The most common diagnostic errors in interpreting MRI of the breast are discussed in this review and experience-based advice is provided to avoid similar mistakes. The most common reasons for false-positive diagnoses are misinterpretation of artefacts, confusion between normal enhancing structures and tumours and, above all, insufficient use of the American College of Radiology breast imaging reporting and data system lexicon, whereas false-negative diagnoses are made as a result of missed tiny enhancement, a background-enhancing breast, or enhancement interpreted as benign rather than malignant.

[Imaging features of granulosa cell tumors of the ovary: about three cases]. / Aspect en imagerie des tumeurs de la granulosa de l'ovaire: à propos de trois cas.

Granulosa cell tumors of the ovary are rare, and included in the sex cord-stromal tumor category. They have a low malignancy potential and generally have a good prognosis. They are the most frequent hormone-secreting tumors of the ovary and may lead to suggestive clinical symptoms. Some biological markers (serum inhibin B and AMH) may be helpful for diagnosis, though their sensitivity is not perfect. Preoperative imaging diagnosis remains challenging due to the wide variability in morphology and lack of epidemiological data in the imaging literature (small patient populations). From a review of the clinical and MR imaging features of three cases of granulosa cell tumor of the adult and a review of the literature, we will describe a few imaging features that may suggest the correct diagnosis.

[Tomosynthesis: luxury or necessity?]. / Tomosynthèse: luxe ou nécessité

Digital mammography is replacing conventional film-screen mammography. One of its advantages is to offer options of advanced processing such as tomosynthesis. Tomosynthesis allows to avoid the overlap of tissues depitected on mammograms, and potentially to improve the detection of subtle lesion such as architectural distortion, permits the characterization of masses and of density asymmetry and the accurate measurement of beast lesion by a better delineation of the lesion borders. Furthermore, in cases of superimposition mimicking an abnormality, it can show the lack of a significant finding and decrease the recall rate. However, additional studies are necessary to evaluate its added valve by comparison to mammography in consecutive patients and not only in retrospectively selectioned cases and to define its indication in diagnostic and screening.

[MR Imaging of primary ovarian tumors with pathologic correlation]. / Corrélations anatomopathologiques: IRM des tumeurs ovariennes primitives.

Ovarian tumors are classified based on the cell of origin into epithelial tumors, germ cell tumors and sex cord-stromal tumors. This pictorial essay illustrates the MR imaging features of the main ovarian tumors with pathologic correlation. These key features are helpful to suggest a specific diagnosis or narrow the differential diagnosis, in order to optimize the surgical approach.

[Trauma of the thoraco-abdominal area: imaging strategy]. / Traumatisme thoraco-abdominal: stratégie en imagerie.

The imaging work up of patients following trauma to the thorax and/or abdomen is dependent upon the hemodynamic and respiratory status. In patients with respiratory distress, management is based on a chest radiograph to detect pleural effusion or pneumothorax requiring immediate drainage. In patients with hemodynamic shock despite adequate resuscitation, FAST US may be the only imaging study performed, along with a chest radiograph, prior to laparotomy in the presence of hemoperitoneum. CT is the key to the management of patients with potentially severe trauma based on clinical findings and/or the nature of the trauma. CT analysis must be rigorous and exhaustive to detect lesions responsible for the clinical findings but also to identify dangerous lesions even if not currently symptomatic, such as contained isthmic aortic transection, bowel perforation or diaphragmatic injury. In patients with less severe trauma, the choice between chest radiographs and abdominal US, more economical, and with less radiation, and CT of the thorax and abdomen, more exhaustive and more accurate, will be discussed on a case by case analysis.

[Does breast density have an impact on the indications for MRI?]. / La densité mammaire change-t-elle les indications d'IRM du sein?

MRI indications in breast imaging in breast imaging are now well codified. In diagnostic and screening, MRI in recommended in patients with likely metastatic lymph nodes and in metastasis of unknown cause, and in women with high risk family. In characterisation MRI is recommend in non-calcified subtle findings, non suitable for biopsy. In the staging of a diagnosed breast cancer, MRI has a great impact both for the diagnosis and for the treatment, event if group of women for whom MRI is recommended is still discussed. In follow-up of patients with an history of breast cancer, MRI permits to differentiate recurrence from scarr and to monitor the response to a neo-adjuvant chemotherapy. Dense breast don't constitute a MRI indication by itself, but strengthen recognized MRI indications. Fatty breast easily readable on mammogram don't justify not to perform MRI in the screening of women with high risk family. Conservely in the staging of a breast cancer in an woman or in the monitoring of a neo-adjuvant chemotherapy fatty breast may make US sufficient.

[Tinnitus and stenosis of the cavernous internal carotid artery]. / Acouphènes et sténose de l'artère carotide interne intracaverneuse.

We report a case of isolated unilateral pulsatile tinnitus. Cerebral angiography showed a right intra-cranial internal carotid artery stenosis. Treatment by dilatation and stenting resulted in symptom resolution.