Biomedical subjects
Publications and source records attributed to A Zouaoui.
We report a case of ruptured subarachnoid dermoid cyst which was explored with both CT and MRI. This rare condition results from the accumulation of a large amount of fat with a characteristic aspect at-imaging. Rupture causes fat dissemination in the subarachnoid space. In most cases, CT or MRI can provide sure diagnosis of the tumor and of rupture.
Cerebral venous angiomas are vascular malformations of the brain which, before the advent of modern imaging, and in particular MRI, were thought to be rare. They have a specific angiographic aspect called "caput Meduse" as it corresponds to the description of a large draining vein to which converge numerous radial veins located in the white matter. These true vascular malformations have characteristic histological features making it possible to differentiate them from other vascular malformations, notably cavernomas. These lesions are less scanty than classically believed, being the most frequent malformations encountered in post-mortem examination series. The circumstances in which cerebral venous angiomas are discovered vary considerably, and haemorrhage can be the revealing sign. Some authors regard these malformations as "abnormalities" of white matter veins and not as pathological entities, since they derive from a change in development during embryogenesis, but this theory is not supported by any anatomical evidence. The same authors attribute the bleeding to an associated cavernoma. Whereas CT enables venous angiomas and possible associated cavernomas to be detected, only repeated MRI explorations performed after the finding of venous angioma and hemorrhage can permit, by analysis of signal changes, to confirm or invalidate the non-pathological theory of the venous malformation and its tendency to bleed. Apart from hemorrhages, since gadolinium is used MRI is the most reliable and least invasive means to diagnose angiomas and to detect associated occult angiographic malformations. For this reason, nowadays only hemorrhages require an angiography in search of an arteriovenous malformation demanding prompt treatment. Moreover, MRI makes it possible to detect angiographically occult malformations.
In this retrospective work based on a series of spinal angiograms performed in the Neuroradiology Department of the Salpêtrière Hospital, Paris, we studied the number of examinations that showed one or several anterior radiculospinal arteries at the thoracolumbar level, as well as their origin at different levels from T6 to L3. Analysis of the whole group of 552 patients showed some deviation from the previously published radio-anatomical papers. This was confirmed and illustrated more clearly by the analysis of a series of 174 cases selected among these 552 patients. This second series was particular in that it featured bilateral catheterization of every artery likely to give off a radiculospinal artery at all levels from T6 to L3, thus providing more reliable statistical data. We found that 48% of the patients had their thoracolumbar blood supply based on two anterior radiculospinal arteries the lowest of which was located at, or lower than, T12, and the second and higher one between T6 and T10. Only 45% of the studies showed a blood supply relying on a single anterior radiculospinal artery which most frequently had its origin at T9. In 7% of the cases the thoracolumbar spinal cord was supplied by 3 anterior radiculospinal arteries. Our results demonstrate the presence of at least two different patterns of spinal cord blood supply at the thoracolumbar level, with a variation in the origin of the anterior radiculospinal arteries. These recent findings may increase the reliability and improve the technique of spinal angiography, especially in difficult cases.
The anterior interhemispheric approach for aneurysms of the anterior communicating artery was studied in ten cadavers. This approach presents several advantages over the pterional approach widely used in neurosurgery. It allows direct access to the region of the anterior communicating artery complex with minimal retraction of the brain and preservation of the olfactory tract and the gyrus rectus.
The incidence of infectious maxillary sinusitis (IMS) and its clinical relevance was prospectively studied in 162 consecutive critically ill patients who were mechanically ventilated for a period longer than 7 d. All had a paranasal computed tomographic (CT) scan within 48 h of admission and were divided into three groups according to the radiologic aspect of their maxillary sinuses: Group 1 = normal maxillary sinuses (n = 40), Group 2 = maxillary mucosal thickening (n = 26), Group 3 = radiologic maxillary sinusitis (RMS) defined as the presence of an air fluid level and/or opacification of maxillary sinuses (n = 96). Group 1 patients were randomized between nasal and oral endotracheal intubation with a gastric intubation performed via the same route and had a second paranasal CT scan 7 d later. Endotracheal and gastric tubes were left in their original position in Group 2 patients and a second paranasal CT scan was performed 7 d later. All patients of Group 3 underwent a transnasal puncture for bacteriologic analysis of maxillary sinus content. Forty-five spontaneously breathing patients served as a control group. In all patients with RMS, the occurrence of bronchopneumonia (BPN) was prospectively assessed for 7 d following the initial CT scan. Upon inclusion, only 25% of the patients had normal maxillary sinuses whereas all patients in the control group had normal paranasal CT scans. After 7 d, 46% of Group 2 patients had evidence of RMS. Risk factors for RMS were nasal placement and duration of endotracheal and gastric intubation.(ABSTRACT TRUNCATED AT 250 WORDS)
PURPOSE: To develop a method for direct measurement, using anatomic specimens, of the precision of MR-guided stereotaxic location and to describe its application to a 1.5-T MR unit with a Leksell stereotaxic frame. METHODS: Small pieces of gelfoam (1 X 1 X 1 mm), soaked in gadopentetate dimeglumine, were stereotaxically introduced into formalin-fixed human heads using a Leksell D (three experiments) or G (nine experiments) stereotaxic frame. The head and the frame were then introduced into a 1.5-T MR unit. The target coordinates (as set on the stereotaxic frame by one investigator) were then compared with the MR-determined stereotaxic coordinates (calculated independently by another investigator). The imprecisions Ex, Ey, and Ez in each direction were defined as the differences between the calculated and the chosen coordinates. RESULTS: Regarding the three targets studied with the D frame, mean imprecision Ex was 1.08 +/- 0.50 mm (mean +/- SEM), Ey 0.83 +/- 0.58 mm, and Ez 0.75 +/- 0.25 mm. For the nine targets studied with the G frame, Ex was 0.48 +/- 0.17 mm, Ey 0.69 +/- 0.14 mm, and Ez 0.82 +/- 0.13 mm. Statistical analysis of the results showed no significant difference between Ex or Ey and half the size of a pixel, indicating that, in the axial plane, stereotaxic MR precision is limited only by pixel size. A statistically significant difference was observed in the coronal plane between Ez and half the size of a pixel, but it must be stressed that Ez remained smaller than 1 mm. CONCLUSION: MR-guided stereotaxic location can be used with confidence for most diagnostic, functional, and therapeutic procedures.
Nine patients with neurological manifestations of sarcoidosis were explored by MRI and, in some cases, CT. The MRI examinations were performed in T1- and T2-weighted spin-echo sequences in all patients, with gadolinium injection in seven. Several non-specific lesions were demonstrated, the most frequent of them showing on T2-weighted sequences as high-intensity signals in the periventricular white matter and the semi-oval centres. Other abnormalities, such as infiltrations of the hypothalamo-pituitary region, granulomatous masses within the brain tissue and meningeal infiltrations, were observed. These findings were in agreement with those found in the literature. Gadolinium injection seems to be important in this pathology, as it demonstrates lesions that are not visible on conventional T1- and T2-weighted spin-echo sequences.
Bronchial sutures grafts by epiplooplasty is a method used to allow a better vascularisation of the bronchial sutures. The authors purpose an other method using the pericardial fatty fringes (P.F.F.). The vascularisation of P.F.F. was studied on 30 fresh cadavers and 8 patients before surgery. Angiography of the internal thoracic artery was done in the first group and M.R.I. in the second group. M.R.I. is better than angiography because numerous parietal vessels project in the angiogram, and they overlap pericardial fat fringes vessels.
In all cases of post-traumatic sensorimotor deficit in the lower limbs unexplained by another pathology, it is not unreasonable to suspect a nerve root avulsion. Whenever available, MRI seems to be the choice examination as it is not invasive and provides a three-dimensional exploration. On the basis of two new cases and a review of the literature, the authors discuss the value of various imaging methods in this pathology.
From 93 skulls and 23 foeto-skeletals we give a glimpse of the rhythme of the human foetuse's facial bones growth and the main variations for facial measurements rating during foetal period. The best correlation between foetal age and facial measurements was obtained with facial height (correlation coefficient: 0.96). Evolution of cranio-facial rating, during foetal stages shows essentially: the increase of the height/width facial rating, the same rhythme of growth for frontal and facial width, the rapidly growth of biparietal diameter up to 30 amenorrhea weeks comparatively to the facial and frontal growth in width.
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Four cases of benign choroid plexus papillomas of the posterior fossa in adults are reported: two papillomas developed in the fourth ventricle, one in the cerebellopontine angle, and one extended from the fourth ventricle to the cerebellopontine angle. CT, MRI and surgical findings are described. The MRI characteristics on T1 and T2-weighted sequences are compared with those already published. In three cases the tumour signal observed after gadolinium enhancement was intense and homogeneous. The paramagnetic contrast agent provided direct visualization and better discrimination of papilloma location and extent.
Lymph nodes of the Barety's space (LNLB) often involved in lung diseases are known under various names for a long time ago by pathologists. Our study involves 360 cadavers of adult subjects. The injection of a dye was performed by direct catheterization of a pulmonary segment. L.N.L.B. were directly or indirectly coloured (inter connected ganglionary network) more often from the lobes of the right lung, but from the lobes of the left lung too. From L.N.L.B. the lymphatic flow discharges in the venous confluent of the neck in the right side; in 1/4 of the cases a mediastinal efferent joints the left venous confluent too. From the lower lymph nodes of the space efferents can go to lymph nodes which are located right along the arch of the azygos vein (and then to the thoracic duct) and in the left side the group of left suprabronchial lymph nodes (then either to the thoracic duct in the mediastinum, or to the recurrent chain to the neck). At last, it seems that inside the lymph nodes themselves, lymphatic flows exist, the topography and the nature of which change according to the area interested by the injection.
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