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J P Francke

Publications and source records attributed to J P Francke.

At least 19 recordsLinked to original sources
PubMed2006

[MRI localization of paraclinoid carotid aneurysms].

AIM: The distal dural ring plane (DDRP) separates the intracavernous from the supracavernous paraclinoid internal carotid artery. The purpose of this MRI protocol is to evaluate the position of this plane for the characterization of paraclinoid aneurysms. METHOD: The protocol uses a T2 weighted sequence in two orthogonal planes (diaphragmatic and carotid planes) and two correlation lines in each plane. These lines pass through anatomo-radiological reference points correlated with the medio-lateral and antero-posterior margins of the DDRP. We use the intersection angle of these lines as the inferior radiological limit of the DDRP curve. RESULTS: An aneurysm located above this angle is supracavernous; an aneurysm located below this angle is intracavernous; an aneurysm crossing this angle is transitional. CONCLUSION: In difficult cases, this MRI protocol could help better characterize the exact localization of paraclinoid aneurysms on both sides of the cavernous sinus roof.

Carotid Artery Diseases↗
PubMed2001

Lumbar spinal ganglia enhancement after gadolinium chelate administration: a radio-histological correlation.

The aim of the present study was to assess the frequency of enhancement of lumbar spinal ganglia after Gadolinium chelate injection in patients without radiculopathy, and to correlate the enhancement with histology. This study is based on the analysis of MR lumbar examinations conducted on 18 patients without radicular symptoms, or previous surgery of the lumbar spine, or disease of the nervous system. The patients were imaged with a 1.5 T unit. Sagittal images were first obtained with a T1-weighted turbo spin-echo. Axial and sagittal images were then obtained with a T1-weighted turbo spin-echo, fat-saturated sequence after Gadolinium intravenous injection from the T12/L1 to the L5/S1 level. All 180 spinal ganglia demonstrated an important and homogeneous enhancement after Gadolinium injection. Four spinal ganglia obtained by dissection from four different fresh cadavers were studied by light microscopy to determine the potential relationship between contrast enhancement and presence and topography of vessels within the spinal ganglia. Vessels were particularly abundant at the peripheral zone of the spinal ganglia. The post-contrast enhancement of the spinal ganglia after Gadolinium administration has to be known and may be explained by the microvasculature pattern.

Adult↗
PubMed2001

Rare variations in renal anatomy and blood supply: CT appearances and embryological background. A pictorial essay.

Helical CT angiography is increasingly used for the evaluation of the kidneys and the renal vessels. Knowledge of the potential variants in renal and renal vascular anatomy and of their appearances on helical CT are thus indispensable for radiologists who perform and interpret such examinations. We report six cases of anatomic variants that we encountered in our tertiary referral centre over the past 5 years, during which time we have performed 4850 helical CT angiograms, including 1432 renal artery examinations. These represent rarer anomalies in renal vascularization, most of which were associated with renal malformations (horseshoe kidney with or without cortical torsion, renal malrotation, single kidney, and thoracic origin of a renal artery). We present the helical CT findings and discuss the possible embryological mechanisms and the practical implications of these abnormalities for the radiologist.

Humans↗
PubMed2001

Anatomic study of arcus tendineus fasciae pelvis.

OBJECTIVE: To describe the anatomy of the arcus tendineus fasciae pelvis. MATERIAL AND METHODS: Two fixed female cadaver pelvises (88 and 66 years old) were dissected. RESULTS: The arcus tendineus fasciae pelvis is a 10-cm-long fibrous thickening of the pelvic fascia which is medial to the obturator internus muscle and lateral to the peritoneum. It is inserted on the ischiatic spine and courses downward and anteriorly to the pubovesical ligament. The posterior third of the arcus tendineus fasciae pelvis is fused with the posterior third of the arcus tendineus musculus levatoris ani, forming a curve with upward and anterior concavity. This portion of the arcus tendineus is thick and easy to recognise upon palpation. It is located 1cm slightly above and anterior to the ischiatic spine and 2 cm from of the pudendal vessels, which course around the posterior inferior margin of the ischiatic spine. The superior margin of the median part of the arcus tendineus fasciae pelvis is crossed laterally by vessels for the obturator internus muscle arising from the internal iliac vessels. CONCLUSION: In genital prolapse cure, sutures must be placed through the anterior or median parts of the arcus tendineus fasciae pelvis. In any case, they must remain anterior to the posterior part of the arcus tendineus fasciae pelvis to avoid injury to the pudendal vessels.

Aged↗
PubMed2000

Radio-anatomic demonstration of the vertebral lumbar venous plexuses: an MRI experimental study.

The aim of this study was to provide a basis of knowledge of the anatomy of the venous plexuses in the lumbar spine both in anatomical slices and in MR images in order to help the analysis of these structures in MR images of living subjects. Four fresh cadaveric lumbar spines were studied after the injection of coloured gelatin mixed with gadolinium. The specimens were injected by an intraosseous technique. Axial and sagittal fat-saturated T1-weighted MR images were performed on the specimens. Thereafter, specimens were frozen and cut into 5-mm thick slices, three in the axial plane and one in the sagittal plane. All the components of the internal and external venous plexuses were identified on the MR images in correlation with the corresponding anatomic sections. The MR anatomy of the venous system of the lumbar spine is important as it has been implicated in many pathophysiological mechanisms and as it may also cause pitfalls in MR imaging.

Cadaver↗
PubMed2000

Thoracic outlet: anatomic correlation with MR imaging.

OBJECTIVE: The purpose of this report is to describe the normal MR anatomy of the thoracic outlet and its modification after postural maneuvers using an anatomic-MR imaging correlation. CONCLUSION: MR imaging appears to be a useful technique to study the thoracic outlet and its contents because of its excellent soft-tissue depiction and its multiplanar capabilities. T1-weighted images obtained in the sagittal plane clearly depicted the different compartments of the cervicothoracic-brachial junction. Hyperabduction maneuvers may have potential applications in the assessment of the thoracic outlet syndrome by showing the location of compression.

Aged↗
PubMed2000

[Arcus tendineus fascia pelvis: anatomical study].

OBJECTIVE: To reveal the anatomy of arcus tendineus fascia pelvis. MATERIAL: and methods. 2 fixed female cadaver pelvises (88 and 66 years old) were dissected. RESULTS: The arcus tendineus fascia pelvis is a fibrous recess of the pelvic fascia which is 10 cm long, laterally to the obturator internus muscle and medially to the peritoneum. It reaches the ischial spine lower and anteriorly to the pubo-vesical ligament. The third posterior part of the arcus tendineus of the pelvic fascia is commun with the posterior part of the arcus tendineus of the levator ani. This third posterior part is like a curve concave anteriorly. This curve is thick and easy to recognize by the palpation. This third posterior curve is 1cm in front of the ischial spine and 2cm in front of the pudendal vessel which took place behind the ischial spine. The vessels of the obturator internus muscle originated from the internal iliac vessel and crossed laterally the median part of the arcus tendineus of the pelvic fascia. CONCLUSION: Sutures must be placed through the anterior and median part of the arcus tendineus fascia pelvis, in front of the posterior part of the arcus tendineus fascia pelvis to avoid any injury to the pudendal vessels.

Aged↗
PubMed1998

Duplication of the pituitary gland in a newborn with median cleft face syndrome and nasal teratoma.

A newborn suffered immediate neonatal respiratory distress because of an obstructive, soft-tissue nasal mass. Clinical examination revealed a cleft palate with a protruding polypoid mass. CT and MRI showed a heterogeneous nasopharyngeal mass and associated intracranial abnormalities - duplication of the hypophysis and hypoplasia of the corpus callosum. Duplication of the hypophysis is a very rare malformation, only 13 cases having been previously described. The suggested pathogenesis is duplication of the prechordal plate and anterior end of the notochord during early embryological development.

Cleft Palate↗
PubMed1998

[Imaging cranial nerves with inframillimetric T2-weighted MRI].

Fifty files were evaluated to determine the normal anatomy of the cranial nerves. All the cranial nerves were studied including the labyrinth, in different planes with a 3DFT-CISS imaging technique. The 3DFT-CISS is especially interesting to study cranial nerves because of the excellent contrast with CSF-fluid and the possibility of thin sections. It might be essential for the diagnosis of neuralgia and cranial nerves paralysis.

Cranial Nerves↗
PubMed1998

[Anatomic variants of Meckel's cave on MRI].

Magnetic resonance imaging (MRI) gives an accurate analysis of Meckel's cave variability. Images were acquired in 50 patients with several sections for anatomical comparison. Using several sections, MRI is a suitable method for better analysis of the trigeminal cistern. The most frequent findings are symmetrical trigeminal cisterns. Expansion of Meckel's cave or its disappearance has pathological significance.

Humans↗
PubMed1997

Anatomic basis for auditory brainstem implant.

Profound bilateral retrocochlear deafness cannot respond to a cochlear implant. For such patients only electrical stimulation of the cochlear nucleus complex can achieve, at best, a partial restoration of hearing. Based on the experience of the W.F. House group at the House Ear Institute in Los Angeles, we have developed an implantable device with many surface electrodes. A personal study has enabled us to establish the main relationships of the nucleus with the aim of inserting the device in contact with it, and to verify its effectiveness in the region. Histological study of anatomic specimens has shown the presence of spheroid neurone, considered to be the secondary neurone of the auditory pathway, at the level of the area of implantation.

Brain Stem↗
PubMed1997

[Identification of the central sulcus using the scanner and MRI].

Methods to directly and indirectly identify the central sulcus are presented. In the axial plan, direct method is remarkable but obviously requires good visualization of the sulci in the central region. Sulci are readily visible in 90% of the cases on CT scans and in 50% of the cases on MRI. The method can also be applied when tumoral development erases the cerebral sulci by direct lecture of the controlateral rolandic region and right-left transfer. Within the precision limits of the method, it can be considered that the central sulci are symmetrical. The main signs are: the relative morphologies of the superior frontal sulcus and the precentral sulcus, the hook-shaped aspect of the middle part of the central sulcus, the internal end of the central sulcus projection anteriorly to the pars marginalis, the bifid nature of the internal end of the posterior central sulcus contouring the pars marginalis, and the lesser thickness of the posterior central gyrus compared with the precentral gyrus. The indirect method is less precise and is used when the direct method is unsuccessful. The central sulcus is identified on the sagittal images and, using the lateral view of the skull as a reference image, the topographic information is transferred to the axial images.

Brain↗
PubMed1996

CT and MR imaging of squamous cell carcinoma of the tongue and floor of the mouth.

Because contemporary treatment of oral cavity cancer involves procedures that spare the tongue and mandible, an adequate assessment of the oral cavity is essential for appropriate surgical and radiation therapy planning. Computed tomography (CT) and magnetic resonance (MR) imaging, which allow differentiation between soft tissues, are valuable tools for assessing this complex region. Their main advantage resides in their capacity to show at best the normal anatomy and the exact extent of a low-lying tumor. For display of soft tissues and tumor, MR imaging, being a multiplanar and multicontrast technique, is superior to CT. Nonenhanced T1-weighted MR imaging is better for defining the exact extent of medullary bone invasion, which appears as a low-signal-intensity area within hyperintense medullary fat. CT is optimal in detection of cortical bone invasion, which appears as an interruption or erosion of the peripheral hyperattenuating rim. Thus, in cancer of the tongue, MR imaging should be performed first. If tumor extension to the mandible is suspected (due to clinical or MR imaging findings), CT should be added. In cancer of the floor of the mouth, both MR imaging and CT should be performed in the initial work-up, especially in those cases in which there is a clinical doubt about mandibular extension of disease. The main drawback of both modalities is their lack of specificity; other methods are needed to discriminate between tumors and inflammatory or infectious diseases, particularly in the mandible. However, once the diagnosis has been confirmed histologically, treatment can be chosen based on complementary information obtained from CT and MR imaging.

Carcinoma, Squamous Cell↗
PubMed1995

High resolution T1 weighted magnetic resonance imaging of the deep brain structures using a reduced bandwidth.

High spatial resolution T1 weighted images of the brain were acquired in 5-13 min on a whole-body magnetic resonance imager operating at 1.5 T. In order to obtain 5-8 cm field of view images, the receiver bandwidth (Bw) was lowered to 2 kHz. The use of a 2 kHz Bw, instead of the standard 16 kHz Bw, partially compensated the signal loss due to the small pixel size by increasing the signal-to-noise ratio, without scan time penalty. The chemical shift artifact associated with reduced Bw was not observed because fat signal is negligible in the brain.

Brain↗