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Biomedical subjects

M Laval-Jeantet

Publications and source records attributed to M Laval-Jeantet.

At least 37 records · Page 2Linked to original sources

[Detection of cancer of the prostate. A study of 600 cases].

A free screening consultation for carcinoma of the prostate was proposed to men over the age of 50 years working in different companies in the areas of Paris. This consultation included a digital rectal examination, a blood test for determination of serum acid phosphatase and prostatic specific antigen, and two dimensional trans-rectal ultrasonography of the prostate. 600 patients were seen. 575 were evaluable. Prostate biopsy was recommended in 152 men. Ninety-three prostate biopsies were performed. Eighteen prostatic cancers and 1 urothelial cancer invading the prostate were detected with an overall incidence of prostate cancer of 3.1%. Radical prostatectomies were performed in 10 of the 18 patients with a prostate cancer. Sensitivity of digital rectal examination ultrasonography and PSA were respectively 42.8%, 47.3% and 68.4% with an abnormal serum PSA level defined as being greater than 5 ng/ml. The predictive value of a positive ultrasonography (18.7%) contrasts with the predictive value of a positive digital rectal examination (30.7%) and serum PSA (30%). Digital rectal examination and determination of serum prostatic specific antigen seem to be the most useful tests for mass screening of prostate cancer. Transrectal ultrasonography is very useful for guided prostatic biopsy and for a better topographic evaluation of the tumor.

Aged↗

[Changes in bone volume and mineral density during aging in humans. In vitro study on 80 subjects].

The extent of bone loss was measured and compared at three characteristic skeletal sites: the humerus, iliac crest and vertebrum. The most important effect of ageing is the fall in bone volume: reduction of bone trabeculae, thinning of compact bone and increase in intracortical porosity. Between 40 and 80 years of age, women lose 42 percent of their vertebral spongy tissue, 29 percent of their iliac spongy tissue and 31 percent of humerus cortical bone. The mean degree of mineralization of bone tissue remains constant between 40 and 80 years of age. Cortical bone is mineralized to a greater extent than spongy bone: 1.20 g/cm3 versus 1.0 g/cm3. Bone loss from different skeletal sites varies; within a given bone-organ it varies from one point to another. The mineral content of the iliac crest differs from that of the vertebrum, but the change is parallel at these two sites.

Adult↗

Artifacts on lung CT scans: removal with Fourier filtration.

A preliminary study was done of Fourier analysis of high-resolution computed tomographic (CT) images of normal pulmonary parenchyma. A two-dimensional fast Fourier transform was applied to 20 regions of interest (64 x 64 pixels) obtained from CT images of six lungs. A qualitative analysis of the spectra and the application of filters in the frequency domain allowed the characterization and removal of reconstruction artifacts. Selective application of a low-pass filter removed these parasitic frequencies and clearly enhanced the quality of the image.

Filtration↗

[Magnetic resonance imaging of cancer of the prostate. Preliminary study].

Twenty-two patients with prostatic carcinoma have been studied by magnetic resonance imaging (MRI). Twenty-three examinations have been done for 2 stage A, 11 stage B, 2 stage C and 7 stage D. Prostatic signal and locoregional extension have been compared with rectal examination and the 3 prostatectomies. Cancer looked homogeneous in 4 cases, heterogeneous in 10 cases with a nodule in 5 cases either with hyper of hyposignal compared to the normal prostate. Local extension in stages C and D is seen, especially to the periprostatic fat and seminal vesicles. MRI appears to be sensitive but poorly specific in the diagnosis of prostatic cancer. On the other hand, it is an interesting examination in the staging of prostatic cancer. These results must be confirmed with more comparisons of images and prostatectomy specimens.

Aged↗

[Value of a new non-ionic contrast medium, iopromide 300 in renal arteriography using an arterial route. Comparative study with ioxaglate 320 mgI/ml].

Thirty-nine patients with hypertension were included in a prospective randomized trial comparing two contrast media in intra arterial digital subtraction arteriography of renal arteries. Efficacy and safety were evaluated for a new non-ionic contrast medium, iopromide 320 and the ionic low-osmolar medium, ioxaglate 320 mgI/ml. We have been able to show a statistically significant difference between these two products: iopromide 370 is, in this situation, less painful than ioxaglate 320 mgI/ml.

Angiography, Digital Subtraction↗

[Contribution of MRI in the staging of cancer of the bladder. Apropos of 40 cases].

56 patients with bladder carcinoma were examined by magnetic resonance in the pre-operative staging. In 40 patients where total cystectomy with enterocystoplasty and pelvic node dissection were performed, a good correlation with surgical and pathologic findings was obtained. MR examination using T1 (TR 400 ms, TE 28 ms) and T2 (TR 1,200-1,600 ms, TE 40 80 120 ms) weighted images in different planes where performed after biopsy of the bladder tumor through endoscopy and within 1 or 2 weeks before surgery. Neoplasms were characterized by site, size and growth pattern. Extension through the deep muscle of the bladder wall was correctly identified in 95% with a sensitivity of 95% and a specificity of 95%. Extension through perivesical fat was assessed accurately in 85% with a sensitivity of 66% and a specificity of 100%. Accuracy in evaluating invasion of adjacent organs was 85%, sensitivity 44%, specificity 96%. Lymphadenopathy has been accurately assessed in 97.5% with a sensitivity of 83% and a specificity of 100%. MR correctly staged the tumor according to TNM classification in 24/40 (60%) patients, overestimated the extension in 3/40 (7.5%) and underestimated the extension in 13/40 (32.5%).

Adult↗

[Imaging technics in extra-cardiac thoracic amyloidosis].

This report deals with five observations of tracheobronchial, pleuropulmonary and mediastinal amyloidosis. Exploration was performed with plain radiographs, computed tomography in three cases, and magnetic resonance imaging in one case of tracheobronchial and interstitial amyloidosis. After their review of literature, the authors describe the main features of extracardiac thoracic amyloidosis observed with imaging and establish the contribution of the various techniques to the diagnosis and follow-up of the disease.

Aged↗

[High-resolution x-ray computed tomography in lymphoid interstitial pneumonia].

Three patients with lymphoid interstitial pneumonia (two HIV 1+ patients with chronic lymphadenopathic syndromes and one with a not-characterized autoimmune disease) have been studied with high-resolution computed tomography (HR-CT). This technique reveals septal lines, small reticulonodular opacities, polyhedral micronodular opacities, "ground-glass" opacities and a dense, subpleural, curved broken line in one patient. The lesions dominate in the bases of the lungs. They are not characteristic for lymphoid interstitial pneumonia. If a patient present with a chronic lymphadenopathic syndrome, the diagnosis of an opportunistic infection should not be automatically made, since the syndrome can be caused by lymphoid interstitial pneumonia.

Adult↗

[Magnetic resonance imaging of the knee menisci. Normal aspects. Misleading images. Meniscus degeneration. Anatomic correlations].

The authors report the result of a study on 5 knees of fresh corpses explored with magnetic resonance imaging, including 1 examined before and after intraarticular contrast injection, and on 15 asymptomatic subjects examined with the same procedure. A very thorough study of the menisci and of their attachment, ie. The tibial insertion of the menisceal horns, the transverse ligament, and the meniscofemoral ligament, is possible with T1-weighted MR sequences. The T2-weighted sequences, either following intraarticular contrast injection or in cases of articular effusion, allow analyzing the capsular attachments of the posterior horn of the lateral meniscus and its relationships with the tendon of the popliteal muscle. Five misleading images must be known for the exploration of the menisci, in order to avoid a number of interpretation problems. Images of type I and II initial meniscus degeneration are observed in 47% of all cases (control group). One case of menisceal cyst developing in the anterior horn of the lateral meniscus, with anatomical correlation, is also reported.

Adult↗

[Magnetic resonance imaging in paralysis of the upper limb of traumatic origin].

We have used magnetic resonance imaging in addition to the other imaging techniques for the examination of 31 patients with traumatic upper limb paralysis. The therapeutic indications of traumatic brachial plexus paralysis depend on the early and precise assessment of the lesions. Computed tomography with a contrast injection at a lumbar level opacifying the subarachnoid spaces provides a morphological study of the canal, spine and nerve roots and of container-contents relationships. In our experience, the diagnostic reliability for the detection of intraspinal radicular lesions is 86%. A study in all 3 spatial planes is possible with MRI with T1- and T2-weighted or gradient echo sequences. The reliability of the technique for the diagnosis of meningoceles in the detection of nerve root avulsion is similar to that of CT (85%). The excellent spatial resolution and natural high contrast allow following the nerve roots in their extraspinal course and determining the site of nerve trunk rupture (50%). The use of oblique and double-obliquity sections should yet improve these results. These first results lead us to proposing magnetic resonance imaging for the exploration of traumatic lesions of the brachial plexus. This nonagressive, more precise and more complete assessment of the lesions certainly has a significant influence on therapeutic choice.

Adolescent↗

Separation of diffusion and perfusion in intravoxel incoherent motion MR imaging.

Intravoxel incoherent motion (IVIM) imaging is a method the authors developed to visualize microscopic motions of water. In biologic tissues, these motions include molecular diffusion and microcirculation of blood in the capillary network. IVIM images are quantified by an apparent diffusion coefficient (ADC), which integrates the effects of both diffusion and perfusion. The aim of this work was to demonstrate how much perfusion contributes to the ADC and to present a method for obtaining separate images of diffusion and perfusion. Images were obtained at 0.5 T with high-resolution multisection sequences and without the use of contrast material. Results in a phantom made of resin microspheres demonstrated the ability of the method to separately evaluate diffusion and perfusion. The method was then applied in patients with brain and bone tumors and brain ischemia. Clinical results showed significant promise of the method for tissue characterization by perfusion patterns and for functional studies in the evaluation of the microcirculation in physiologic and pathologic conditions, as, for instance, in brain ischemia.

Bone Neoplasms↗

Changes in lipid and lipoprotein levels and Achilles tendon diameters and indices in familial hypercholesterolaemic patients with tendinous xanthomatosis treated by diet and bezafibrate for 2 years.

Thirteen young adult patients suffering from heterozygotic familial hypercholesterolaemia with tendinous xanthomatosis, previously treated with a suitable special diet, were studied to assess the effect of bezafibrate, given for 2 years at a dose of 800 mg/day, on plasma lipid and lipoprotein levels and on changes in size of the Achilles tendon xanthomas. Measurements were made before and at intervals during treatment, the tendinous xanthomas being measured by an echographic procedure to give data on antero-posterior and lateral diameters, thus enabling an Achilles tendon index to be defined. The results confirm the hypolipidaemic activity of bezafibrate, changes in the levels of total cholesterol, triglycerides, lipids and lipoproteins (LDL, VLDL and HDL) being similar in direction and magnitude to those reported previously. A significant regression in the size of the Achilles tendon xanthomas was observed in 11 of the 13 patients, and the regression in the Achilles tendon index correlated significantly with a favourable change in the ratio HDL/LDL + VLDL. It is suggested that, as a result of this objective observation, a favourable effect of bezafibrate treatment would possibly be seen on the anatomical atheromatous lesions which are usual in this type of hyperlipidaemia.

Achilles Tendon↗

Imaging of posttraumatic brachial plexus injury.

After reviewing a series of 220 patients operated upon between 1975 and 1985 for traumatic brachial plexus injuries, the authors present the results of 103 myelographies, 48 computed tomographies (CT scans) combined with standard myelography, and 25 series of images obtained by magnetic resonance imaging (MRI). To evaluate precisely the type and level of injury, the accuracy of these three techniques was compared with clinical and operative findings. The accuracy of myelography was considered good in 84% of the cases, but 4% were evaluated as false positive results and 12% as false negative or doubtful results. The combined CT scan and myelography reduced the number of doubtful results and accuracy reached 94.25%, but they did not visualize the roots distal to the spinal foramina. MRI correlated well with CT scan images and, in addition, offered visualization of distal radicular injuries. MRI seems a promising diagnostic procedure and should also help to situate nerve grafts and check their viability.

Adult↗