Metanephric adenoma diagnosed on biopsy in an infant: a case report

BACKGROUND

Metanephric adenoma is a rare benign renal tumor of the kidney, uncommonly observed in children. It is often misdiagnosed preoperatively as a malignant neoplasm, leading to an unnecessary nephrectomy. The challenge is to make the right diagnosis preoperatively and therefore manage it with conservative surgery. We report a case of a child with metanephric adenoma who underwent nephron-sparing surgery.

CASE PRESENTATION

A renal tumor was discovered fortuitously in an 18-month-old Caucasian girl with several congenital malformations. Investigations showed a 28 × 27 × 27 mm left renal mass centrally located, well defined, nonvascularized, with no calcifications and which compressed the adjacent renal tissue. Furthermore, there were no signs of metastasis. The decision of a multidisciplinary meeting was to perform a computed tomography (CT)-scan-guided biopsy. Histologic examination concluded it was a metanephric adenoma. We performed a left open partial nephrectomy via a flank retroperitoneal incision. The final histopathological examination confirmed the diagnosis. The postoperative course was uneventful.

CONCLUSION

Preoperative diagnosis of metanephric adenoma is challenging. Because of the high probability of unnecessary radical nephrectomy, preoperative biopsy can be safe and determining to guide a more conservative approach so nephron-sparing surgery can be performed.

Secondary closure of large omphalocele using component separation technique: A pediatric case report

Introduction and importance

Component separation technique is utilized in adults to repair large abdominal wall defects but rarely used in children. We report a successfully performed component separation technique in a child after neonatal Gross closure for large omphalocele without biologic mesh placement.

Case presentation

A 6-year-old girl was treated at the age of 4 days for omphalocele type 2 according to Gross technique. She reconsulted six years later. Clinical examination showed a large eventration measuring 150 ∗ 100 mm. CT scan revealed a broad collar of 150 mm and a large pocket containing liver, transverse colon, stomach and part of the small intestine. The child was proposed for a cure of the eventration using synthetic mesh type GORTEX. Intraoperatively, releasing bowel adhesions with abdominal wall resulted in perforation of the small intestine. Faced with the inability to use the mesh we resorted to abdominal closure with component separation technique. The postoperative was simple without complications or recurrence of the eventration. Follow up was of 4 years.

Clinical discussion

Staged surgical closure and non-operative delayed closure are the two distinct strategies for managing giant omphaloceles. By providing closure with less intra-abdominal pressure, the Component separation technique is a procedure which can be used in the two strategies. It may minimize the complications associated with large omphalocele management.

Conclusion

Faced with the impossibility of using a mesh, the component separation technique must be recognized as part of the therapeutic arsenal for secondary closure in children with a giant omphalocele.

•

We report a case of a secondary closure of large omphalocele using component separation technique in 12 years-old girl.

•

Our pediatric patient illustrates the safety and feasibility of this technique in children without any complication.

•

Component separation technique must be recognized in the therapeutic arsenal closure of large abdominal wall defect in children

Is pneumoperitoneum specific of post-traumatic appendicitis? Case report and literature review

Introduction

Acute appendicitis and blunt abdominal trauma may co-exist, imposing a dilemma of whether there is only coincidence or there is a cause to effect relationship. The etiopathogenesis of this rare association remains obscure. Pneumoperitoneum has rarely been described in patients with acute perforative appendicitis following abdominal trauma.

Case presentation

We report a rare case of acute perforated appendicitis after blunt abdominal trauma in an 8-year-old boy revealed by a pneumoperitoneum. We also reviewed the literature on this rare condition to assess the specificity of pneumoperitoneum in the diagnosis and to understand its etiopathogenesis.

Conclusion

Abdominal pain and fever several days after an abdominal trauma may be a sign of post-traumatic appendicitis in the pediatric population. Pneumoperitoneum is not specific of post-traumatic appendicitis but it can be a protective sign, since it will lead to immediate laparotomy in patients with an unrecognized surgical abdomen.

Spontaneous perforation of common hepatic duct: an intraoperative surprise

Background

Pediatric spontaneous bile duct perforation is one of the rare causes of acute abdomen in infants. With a highly variable presentation, diagnosis and treatment can prove challenging. We report a case of spontaneous common hepatic duct perforation mistaken for appendicular peritonitis.

Case presentation

An otherwise healthy 3-year-old boy presented to the emergency department with complaints of abdominal pain, distention, bilious vomiting, and fever evolving for 4 days. Preoperative ultrasound was suggestive of appendicular peritonitis. Laparotomy revealed abundant biliary fluid, a distended gallbladder with thickened and inflammatory wall, and a macroscopically normal appendix. Intraoperative cholangiography showed a leak of contrast from the anterior wall of the common hepatic duct, 2–3 mm below the upper biliary confluence and 2 cm above the junction of the cystic duct to the common hepatic duct. A cholecystostomy was performed, and two external intraabdominal drains were placed. A retrograde cholangiogram was performed on postoperative day 21 showing no extravasation of contrast product. The patient was discharged on postoperative day 25.

Conclusion

Spontaneous perforation of the common hepatic duct is a rare phenomenon. It should be considered as a differential diagnosis in pediatric patients that present with unexplained peritonitis. The optimal method of diagnosis and management remains controversial.

[Pulmonary arteriovenous malformation in a bronchoscopy simulating a carcinoid tumour]

The authors report a case of pulmonary arteriovenous malformation in a 48-year-old man. The bronchoscopy revealed a fragile lingular tumoral formation. The diagnosis was based on the thoracotomy and the histopathological findings. The endoscopic features and the different diagnostic options of pulmonary arteriovenous malformation are discussed.

Proposed graphical system of evaluating disc–condyle displacements of the temporomandibular joint in MRI

The aim of this preliminary study was to standardize the reading of magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ). The MRI was conducted on a control group of eight subjects. In this study, the analysis of joint relationships was limited to the oblique sagittal plane, during the movement of controlled opening. The sections were analyzed by a computer-assisted quantitative method of graphical evaluation. The total surface area (TS) of the disc section was divided into an anterior surface area (AS) and a posterior area (PA), in accordance with a line joining the center of the condyle (C) to the center of the articular tubercle of the temporal bone (T). The disc-condyle relationships in the chosen plane of section were evaluated by the AS/TS ratio. If TS remains relatively constant, the AS/TS values on average decrease from 0.5 to 0.3 between the closed mouth position and the 25 mm open position. The results show good intra-observer reproducibility (p=0.26), evaluated by Wilcoxon's test. In conclusion, this protocol enables the displacement of the disc-condyle assembly during mouth opening to be described. Observed on a larger sample, the AS/TS would be able to show a range of variability in functional disc positions.

Functional anatomy of the human lateral pterygoid muscle

The authors studied the lateral pterygoid muscle of 179 fresh cadavers by both anatomical dissection and magnetic resonance imaging. The aim was to define the general morphology and the architectural organisation of the lateral pterygoid muscle. Dissection plane by plane, anatomical sections in different planes of space and dissections via multiple approaches on harvested blocks allowed the demonstration that the lateral pterygoid shows an architectural arrangement different from that which is usually described but similar to that, from its typically penniform structure of the masseter and the medial pterygoid. The anatomical situation of this muscle gives rise to numerous differences in opinion much to its morphology as to its functional examination. This study has shown that one part of the muscle has a typical penniform structure made up of alternating musculo-aponeurotic layers and by the absence of individual muscle bellies. In addition the particular shape of this muscle makes it useless to insert intramuscular electrodes in its only accessible portion, which makes the results of electromyographic studies debatable.

General organization of the human intra-masseteric aponeuroses: changes with ageing

A magnetic resonance imaging (MRI) study of the layout of the aponeurotic layers of the masseter muscle was done on a series of 18 patients, aged from 6 to 79 years. The study was undertaken in parallel with a study on 169 cadavers to correlate the anatomical dissection and MRI findings. The aims were as follows. On the cadavers, the results of dissection were compared with the results of MRI: the layer-by-layer dissections and the anatomical dissections of the different spatial planes have shown that the masseter muscle displays a penniform structure typically characterized by the presence of alternating muscular/aponeurotic layers. The anatomical sections and the MRI section in the same plane allowed the appearance of the intra-muscular aponeurotic layers on MRI to be defined. The patients were then divided into four age cohorts, and the arrangement and variations of the human masseter muscle defined as a function of age. This double study has brought new elements to the understanding of the timing of the development of the intra-muscular aponeurotic structures and the modifications which they undergo with ageing. It appears that the aponeurotic structures only become individually identifiable towards the age of 17 years and that ageing is accompanied by a reduction in the transverse muscular mass accompanied by a verticalization of the aponeurotic layers.

Functional anatomy of the human temporal muscle

The authors carried out an anatomical and magnetic resonance imaging study on the architecture of the mandibular elevator muscles of 169 cadavers. The aim of the study was to define the organisational architecture of the human masseter, temporal and pterygoid muscles. Layer by layer dissection and anatomical cuts in different spatial planes showed that the temporal muscle has a different architecture to the other mandibular elevator muscles. Indeed this muscle does not have the pennate structure of the masseter and pterygoid muscles. Through electromyographic study the behavior of this muscle allowed the establishment of its functional segmentation during the masticatory cycle. Our study showed three distinct anatomical portions in the middle of the temporal muscle which correspond to this functional classification. The MRI study confirmed the results of our anatomical study.

Midbrain deafness with normal brainstem auditory evoked potentials

The authors report two cases of patients with word deafness. The word deafness occurred after a head injury for the first patient and after an arterio venous malformation embolization for the second patient. MRI demonstrated bilateral lesions of the inferior colliculi but brainstem auditory-evoked potentials (BAEP) were within normal limits. These cases demonstrated that lesions involving the two inferior colliculi induced pure word deafness but do not affect BAEP.

Carotid artery stenosis: prospective comparison of CT, three-dimensional gadolinium-enhanced MR, and conventional angiography

PURPOSE

To prospectively compare gadolinium-enhanced magnetic resonance (MR) angiography and computed tomographic (CT) angiography with digital subtraction angiography (DSA) for use in detecting atheromatous stenosis and plaque morphology at the carotid bifurcation.

MATERIALS AND METHODS

Forty-four carotid arteries (in 22 patients) were analyzed by using CT angiography, enhanced MR angiography, and DSA. CT and enhanced MR angiograms were reconstructed with maximum intensity projection and multiplanar volume reconstruction. The following four features were analyzed: degree of stenosis on the basis of North American Symptomatic Carotid Endarterectomy Trial criteria, length of stenosis, luminal surface, and presence of ulcers.

RESULTS

There was significant correlation between CT angiography, enhanced MR angiography, and DSA for degree and length of stenosis. With enhanced MR angiography and CT angiography, degree of stenosis was underestimated in two of 44 cases. No case of overestimation with CT angiography was found. Severe internal carotid artery stenoses were detected with high sensitivity and specificity: 100% and 100%, respectively, with CT angiography; 93% and 100%, respectively, with enhanced MR angiography. Luminal surface irregularities were most frequently seen at CT angiography. With CT angiography and enhanced MR angiography, more ulceration was detected than with DSA.

CONCLUSION

There was a significant correlation between CT angiography, enhanced MR angiography, and DSA in evaluation of carotid artery stenosis. Enhanced MR angiography or CT angiography can be used to adequately evaluate carotid stenosis.

Functional organization of the human masseter muscle

The authors carried out an anatomic and magnetic resonance imaging study of the architecture of the elevator muscles of the mandible in 169 cadavers. The aim of this study was to define the architectural organization of the human masseter muscle, temporalis and pterygoid muscles. Layered dissections and anatomic sections in different spatial planes showed that the masseter muscle exhibited a typical pennate structure consisting of a succession of alternating musculoaponeurotic layers. The muscle had three well-differentiated parts: the superficial, intermediate and deep masseter muscles. The same pattern was constantly found: 1) for the superficial masseter, two alternate musculoaponeurotic layers oriented at 60 degrees in relation to the plane of occlusion, 2) for the intermediate masseter, a single musculo-aponeurotic layer oriented at 90 degrees in relation to the occlusal plane, 3) for the deep masseter, three musculoaponeurotic layers whose general orientation was at 90 degrees for the bounding layers and 110 degrees for the intermediate layer. The MRI study confirmed the reality of this architectural arrangement.

Magnetic resonance imaging of cerebral central sulci: a study of monozygotic twins

The cerebral central sulci, seat of the sensorimotor cortex, vary anatomically in form, length and depth among individuals and present a left/right asymmetry. The purpose of this work was to measure central sulcus's lengths, at the surface and in-depth, in each hemisphere of monozygotic twins in order to evaluate the influence of environmental factors on the morphometry and asymmetry of this structure. A measurement technique on MR images of the brains using 3 D software was developed. Two operators applied this technique to measure central sulcus lengths at the surface of the brain and in-depth in each hemisphere. Besides the fact that the technique developed gave high Intraclass Correlation Coefficients (ICC) for the surface lengths (mean value 0.94), and slightly less high for the in-depth length (mean value 0.87), we found a weak (from 0.57 to 0.73 for raw data) but significant ICC between homologous sulci in pairs of twins. In addition, the ICC for asymmetry indices were not significant. Hence, if central sulcus morphometry is in part genetically influenced, these results show that nongenetic factors are nonetheless important in their development.

Statistical sulcal shape comparisons: application to the detection of genetic encoding of the central sulcus shape

Principal Component Analysis allows a quantitative description of shape variability with a restricted number of parameters (or modes) which can be used to quantify the difference between two shapes through the computation of a modal distance. A statistical test can then be applied to this set of measurements in order to detect a statistically significant difference between two groups. We have applied this methodology to highlight evidence of genetic encoding of the shape of neuroanatomical structures. To investigate genetic constraint, we studied if shapes were more similar within 10 pairs of monozygotic twins than within interpairs and compared the results with those obtained from 10 pairs of dizygotic twins. The statistical analysis was performed using a Mantel permutation test. We show, using simulations, that this statistical test applied on modal distances can detect a possible genetic encoding. When applied to real data, this study highlighted genetic constraints on the shape of the central sulcus. We found from 10 pairs of monozygotic twins that the intrapair modal distance of the central sulcus was significantly smaller than the interpair modal distance, for both the left central sulcus (Z = -2.66; P < 0.005) and the right central sulcus (Z = -2.26; P < 0.05). Genetic constraints on the definition of the central sulcus shape were confirmed by applying the same experiment to 10 pairs of normal young individuals (Z = -1.39; Z = -0.63, i.e., values not significant at the P < 0.05 level) and 10 pairs of dizygotic twins (Z = 0.47; Z = 0.03, i.e., values not significant at the P < 0.05 level).

[3D-CT angiography with volume rendering technique in the intracerebral aneurysms]

PURPOSE

Many techniques of 3D reconstruction (MIP, SSD) permit a good evaluation of the circle of Willis in order to detect cerebral aneurysms. More recently, the advent in the clinical practice of a calculation algorithm (VRT) adapted to the workstations for images treatment seems to improve evaluation of the characteristics regarding these aneurysms.

MATERIALS AND METHODS

We report 4 cases with cerebral aneurysms studies with CT-angiography using the technique MIP and VRT.

RESULTS

The VRT, using the totality of image informations, allows a better understanding than MIP about the intracranial cerebral aneurysms including their constitution and 3D localization.

CONCLUSION

The VRT reconstruction permits to obtain quickly good quality and reproductive images, without relationship with threshold.

Intracranial aneurysm on CTA: demonstration using a transparency volume-rendering technique

We report an interesting transparency study using a volume-rendering technique applied to CT angiography in a patient with a sylvian aneurysm. On a single view, all the information required for the aneurysmal treatment could be analyzed. Comparison with maximum intensity projection and virtual endoscopy reconstructions was performed.

Hemispheric asymmetry and corpus callosum morphometry: a magnetic resonance imaging study

Previous post-mortem studies (Aboitiz, F., Scheibel, A.B., Fisher, R.S., Zaidel, E., 1992. Brain Res. 598, 154-161 and Aboitiz, F., Scheibel, A.B., Zaidel, E., 1992. Brain 115, 1521-1541) have shown an inverse association between asymmetry in perisylvian areas and the size of a specific segment, the isthmus, of the corpus callosum (CC) in males. The purpose of this work was to study in vivo the association between hemispheric asymmetry and the total size of the CC in 35 right-handed subjects (16 males, 19 females; mean age 24.9 +/- 3.9). An MRI scan was performed for each subject. The area of the right (RH) and left (LH) hemispheres were measured from images in the sagittal plane and the area of the CC from images in the mid-sagittal plane. The index of hemispheric asymmetry was absolute value((LH - RH)/[(LH + RH)/2]). There was a negative correlation between the absolute value of hemispheric asymmetry and the size of the CC in males (r = -0.55, P = 0.03) but not in females (r = -0.20, P = 0.42). These findings, like those of Aboitiz et al. (Aboitiz, F., Scheibel, A.B., Zaidel, E., 1992. Brain 115, 1521-1541), suggest a sex-dependent decrease in interhemispheric connectivity with increasing hemispheric asymmetry.

Is there a negative correlation between explicit memory and hippocampal volume?

The aim of this research was to study the relationship between explicit memory and hippocampal volume. Seventy healthy adults were administered one implicit memory test and one explicit memory (EM) test and underwent magnetic resonance imaging. The major finding was a negative correlation between the EM test and the right hippocampus/brain volume ratio (t = -0.25, P = 0.03) and the left hippocampus/brain volume ratio (t = -0.27, P = 0.02). This finding is not consistent with pathologic findings, which tend to show a relationship between decrease in memory performance and hippocampal atrophy. This discrepancy is discussed.

Computerized tomographic angiography scan following carotid endarterectomy

The purpose of this study was to evaluate the role of computed tomographic angiography (CTA) for postoperative assessment of carotid endarterectomy (CE). Twenty carotid endarterectomies were performed and controlled by using (1) intraoperative angiography, (2) postoperative duplex scanning and CTA with multiprojection volume reconstruction (MPVR). Intraoperative angiographic controls were deemed satisfactory for all patients. In 12 patients, the postoperative morphological aspect was satisfactory with CTA and duplex scanning. In the eight remaining patients, CTA and/or duplex scanning revealed 12 abnormalities: 3 were equally visualized on CTA and duplex scanning, 6 only on CTA and 3 only on duplex scanning. CTA is a rapid and noninvasive technique allowing the surgeon to get informative and comparative data. It might be an interesting alternative to postoperative angiography.

[Magnetic resonance imaging and the discoid meniscus in children]

Discoid meniscus is an uncommon dysplasia generally affecting the lateral meniscus. Its congenital or acquired origin remains a question of debate. We report 5 cases or lateral discoid meniscus in 4 girls and 1 boy, aged from 6 to 11 years. The main clinical signs were snapping knee and pain. The discoid meniscus appeared in MRI as an abnormally large meniscus extending into the joint space. It appeared as a central band giving increased signal in 3 out of 5 cases. The significance of this probably trauma-induced image was uncertain. Surgery confirmed MRI findings in 4 cases in which total resection of the meniscus was performed. No operation was performed in the fifth case.

Are the brains of monozygotic twins similar? A three-dimensional MR study

PURPOSE

The role of genetic mechanisms and the influence of environmental events in human brain development have been difficult to evaluate. The purpose of this study was to compare the cerebral cortical morphology and midline structures of monozygotic twin pairs using MR imaging.

METHODS

Six observers, blinded to twin pairings, evaluated the 3-D renderings of the cortical surface and midline structures from MR images of seven monozygotic twin pairs. A morphometric analysis of the corpus callosum and of the distance between the anterior and posterior commissures was also performed.

RESULTS

Despite surprising anatomic differences, the brains of the twin pairs were similar enough to enable the observers to distinguish twin pairs from unrelated subjects. Five of six observers correctly identified the brains of all seven twin pairs; the remaining observer failed to make a correct match in only one of seven pairs. Three of six observers identified the midline sagittal images of the related twins in all seven pairs, and the other three identified the related midline sagittal images in five of seven pairs. The results were statistically significant.

CONCLUSION

Although the observed differences in morphologic characteristics between twins necessarily reflect nongenetic influences, the cortical patterns and midline structures of monozygotic twins probably are genetically similar.

Intracranial aneurysm: inner view and neck identification with CT angiography virtual endoscopy

We describe a virtual endoscopy tool applied on CT angiography acquisitions to analyze the neck and inner structures of an intracranial aneurysm. This technique, applied on a basilar artery aneurysm, accurately described its morphology and helped in making a choice between surgical and endovascular treatment.

Three-dimensional computed tomographic angiography in detection of cerebral aneurysms in acute subarachnoid hemorrhage

OBJECTIVE

Three-dimensional computed tomographic angiography (CTA) is a recently developed imaging modality. We demonstrate the value of this noninvasive method in replacing digital subtraction angiography (DSA) in the detection of aneurysms of the circle of Willis in patients with subarachnoid hemorrhage admitted to our institution.

METHODS

A helical acquisition was performed for computed tomographic scans obtained for 120 patients with a 1 mm per second table speed and a 1-mm collimation, 1:1 pitch. Axial source images were transferred on a console Advantage Windows workstation (General Electric, Milwaukee, WI) and CTA was obtained using maximum intensity projection reconstruction. All patients had undergone DSA of the circle of Willis (80 patients preoperatively and 40 postoperatively).

RESULTS

A total of 129 aneurysms were detected in 107 patients. Three-dimensional CTA disclosed nothing abnormal in 13 patients. Ninety-two patients sustained one aneurysm, 10 patients sustained two, 3 patients sustained three, and 2 patients sustained four. All results were confirmed by DSA. In two cases, aneurysms of the middle cerebral artery were defected by CTA but not by DSA. When using angiographic views, the aneurysm was always masked by a branch of the middle cerebral artery.

CONCLUSION

The sensitivity of three-dimensional CTA is comparable with that of DSA, and its specificity is 100%. Because CTA is simple, quick, noninvasive, and reliable, we think that it can eventually replace DSA.

MRI of pituitary adenomas in acromegaly

Adenomas causing acromegaly represent at least a quarter of pituitary adenomas. We studied 12 patients presenting with active acromegaly due to a pituitary adenoma with a 1.5 T superconductive MRI unit. All had T1-weighted sagittal and coronal sections before and after Gd-DTPA; six had coronal T2-weighted images. Surgical correlation was obtained in seven patients. Histologically, there were eight growth hormone (GH)-secreting and three mixed [GH and prolactin (PRL) secreting] adenomas, and one secreting GH, PRL and follicle-stimulating hormone. Macroadenomas (10) were more frequent than microadenomas (2). No correlation was found between serum GH and tumour size. There were nine adenomas in the lateral part of the pituitary gland; seven showed lateral or infrasellar invasion. Homogeneous, isointense signal on T1- and T2-weighted images was observed in six cases. Heterogeneous adenomas had cystic or necrotic components.

[Subarachnoid rupture of supratentorial dermoid cyst: CT and MRI aspects]

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.

MR determination of hippocampal volume: comparison of three methods

PURPOSE

To determine whether measurements of the volume of the hippocampal formation obtained from a three-dimensional acquisition not perpendicular to the hippocampus are statistically different from those obtained from a perpendicular acquisition.

METHODS

Both hippocampi were studied in 10 healthy volunteers with two three-dimensional acquisitions, allowing three different volume-calculation protocols: (a) on sections from a coronal 3-D acquisition not perpendicular to the axis of the hippocampal formation (NOPERP protocol), (b) on sections obtained with the same acquisition but reformatted perpendicular to the axis of the hippocampal formation (REFOR protocol), and (c) on sections from a coronal 3-D acquisition perpendicular to the axis of the hippocampal formation (PERP protocol) obtained with the patient's head tilted backward. To obtain measurements of the volume of the hippocampal formations, an accurate 3-D processing technique was used to segment the hippocampus. In all subjects, two hippocampal formation right-left asymmetry indexes were calculated by using each of the three protocols.

RESULTS

For the right hippocampus, the mean volume was 3.42 cm3 (NOPERP protocol), 4.18 cm3 (REFOR protocol), and 3.91 cm3 (PERP protocol). For the left hippocampus, the mean volume was 3.29 cm3 (NOPERP protocol), 4.02 cm3 (REFOR protocol), and 3.74 cm3 (PERP protocol). For both hippocampi, the differences of the mean volumes were significant between each protocol. However, for both hippocampi, a high correlation was observed between volumes obtained with the different protocols. For the two asymmetry indexes, there were no significant differences for the means obtained with the three protocols.

CONCLUSION

With the use of 3-D acquisitions in the study of hippocampal formation biometry, different procedures lead to significant variations in the absolute values of the volume of the hippocampal formation. However, there is a strong correlation between the results obtained by each method.

[Modern imaging in cerebral vein angioma]

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.

[An angiographic study of spinal vascularization at the thoracic-lumbar level]

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.

Risk factors and clinical relevance of nosocomial maxillary sinusitis in the critically ill

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)

Neurosurgical anatomy of the anterior interhemispheric approach for aneurysms of the anterior communicating artery (26.6.92)

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.

A technique of measuring the precision of an MR-guided stereotaxic installation using anatomic specimens

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.

Intracranial extension of an idiopathic orbital inflammatory pseudotumor

Idiopathic orbital inflammatory pseudotumor (IOIP) with endocranial extension is very unusual. The authors used CT and MR to diagnose IOIP and demonstrate the presence of intracranial extension of orbital and lacrimal gland lesions. While providing additional evidence of IOIP having intracranial extension, this case report emphasizes the need to include IOIP as a possible differential diagnosis when radiologic explorations reveal lesions extending from the orbit to intracranial structures.

MRI in neurosarcoidosis

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.

[Pericardial fatty fringes: preoperative anatomo-radiographic value of their use in the protection of bronchial sutures]

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.

[Parameters of the facial bones in the fetus. Anthropology and medico-legal application for the determination of the fetal age]

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.