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Biomedical subjects

M Claudon

Publications and source records attributed to M Claudon.

At least 55 records · Page 3Linked to original sources
PubMed1997

Three-dimensional CT-scan reconstruction of renal calculi. A new tool for mapping-out staghorn calculi and follow-up of radiolucent stones.

OBJECTIVES: The development of CT scanners (CT scan) with continuous rapid spiral acquisition now allows three-dimensional reconstructions of mobile organs such as kidneys. The aim of this study was to appreciate the merits of this new technique in the field of renal lithiasis. METHOD: This non-invasive technique was applied in 27 renal calculi (23 staghorn and 4 radiolucent stones). The acquisition does not require any injection of contrast material. Reconstruction was carried out by three-dimensional (3D) shaded surface display. RESULTS: 3D reconstruction of calculi permits a precise study of the shape of the stone, and of the number, size and direction of its branches. Therefore, it allows for better planning of the PCNL (number of ports, per-operative pelvi-caliceal exploration ...). Large radiolucent calculi are clearly defined with 3DS, facilitating the follow-up under medical treatment. CONCLUSION: 3D CT scan reconstruction is a noninvasive, cost-effective method which offers high quality 3D images of renal calculi. These results should spur the more widespread use of this technique.

Cost-Benefit Analysis↗
PubMed1997

Malignant change in an intradiploic epidermoid cyst.

We describe a unique case of an intra-diploic epidermoid cyst of the parietal and occipital right bone in a 43 year-old man. The tumor remained quiescent for 12 years and then spontaneously showed malignant changes with intra-cerebral involvement. Fatal outcome occurred one year after surgery, radiation therapy and chemotherapy because of a recurrence. Malignant transformation of the epithelium in epidermoid cyst is very rare. Our case is the first one where this transformation occurred spontaneously without previous surgery.

Adult↗
PubMed1997

Relationship between blood pressure and renin, angiotensin II and atrial natriuretic factor after renal transplantation.

The objective of the study was to assess the evolution of renin, angiotensin II, atrial natriuretic factor (ANF) and blood pressure (BP) in the first trimester following renal transplantation in man Thirty-two recipients were investigated for 3 months post-transplantation. Twenty had a history of hypertension with moderate cardiac hypertrophy. Thirty-one retained their native kidneys. Five kidney donors had a history of mild hypertension. The recipients were perioperatively volume-expanded with 0.9% saline and diuresis was maintained for 48 h with furosemide and dopamine. The sodium intake was 25 mEq/24 hours. Prophylactic immunosuppressive therapy was antilymphocyteglobulins (25 cases), or anti-LFA1 (7 cases) and maintenance therapy was cyclosporine-prednisone (8 cases), or cyclosporine-prednisone-azathioprine (24 cases). Mean BP, serum creatinine, urinary sodium excretion (UNA) and hormonal (renin, angiotensin II and ANF) parameters were collected every other day for the first week after transplantation and then twice monthly. Twenty (62.5%) patients developed hypertension and hypertension was more frequent in patients with a delayed graft function, than in patients with immediate good graft function (10/20 vs. 4/12, p < 0.05%). Both hypertensive (group HBP) and normotensive (group NBP) patients had similar very low renin and angiotensin II plasma levels, after an initial early peak. Analysis of covariance with multiple regression analysis showed that in the HBP patients, BP was negatively correlated with UNA (p = 0.02) and positively with plasma ANF (p < 0.01). The normal BP patients also showed a correlation between BP and UNA, although it was limit of statistical significance (p = 0.05); there was no correlation between ANF and BP. We conclude that the RAS is rapidly depressed after renal transplantation and does not interfere with BP regulation. The hypertension in the early stage of post-transplantation varies inversely with the urinary sodium excretion. The defective sodium excretion, which dominates the effect of the low sodium diet, results in volume overload, increased ANF and volume-dependent hypertension.

Adult↗
PubMed1995

Renal angiomyolipoma: growth followed up with CT and/or US.

PURPOSE: To follow up the growth of renal angiomyolipomas (AMLs). MATERIALS AND METHODS: Patients with known AML (n = 55) were divided into three groups on the basis of initial clinical and computed tomographic (CT) findings: group 1, isolated AML (n = 43); group 2, multiple AMLs without tuberous sclerosis (TS) (n = 6); group 3, multiple AMLs with TS (n = 6). Follow-up ultrasonography (US) and CT were performed in 55 and 31 patients, respectively. Growth of the AMLs (n = 59) was evaluated on the basis of area on initial and follow-up images. RESULTS: Mean percentage growth was 17%, 128%, and 47%, and mean growth rate per year was 5%, 22%, and 18% in groups 1, 2, and 3, respectively. New renal lesions were noted in three patients in groups 1 and 2, but no new lesions were detected in group 3, because of the large number of AMLs. New extrarenal lesions were observed in four, two, and three patients in groups 1, 2, and 3, respectively. No correlation was found between percentage of fatty tissue and growth rate. CONCLUSION: Multiple AMLs show more growth than solitary AMLs.

Adipose Tissue↗
PubMed1995

[Imaging of severe forms of hematoma in the rectus abdominis under anticoagulants].

AIM: To describe the US, CT and MRI pattern of the severe rectus sheath hematoma (RSH) complicating anticoagulant therapy. MATERIALS AND METHODS: CT scans were performed in thirteen patients (12 women, 1 man) aged from 53 to 90 (mean age, 74) with severe RSH. Five patients also underwent ultrasound examination and three MR examination. Nine patients (69%) were receiving subcutaneous injection of heparin, three (23%) oral anticoagulant therapy and one continuous IV infusion of heparin. Clinical diagnosis was reached in 6 cases. Excessive activity of anticoagulant therapy was noted in 4 cases. The location of the RSH, their densities and their signal were analysed. RESULTS: All the RSH were mostly developed in the lower third of the abdominal wall, had a large spreading into the Retzius space and compressed the bladder and/or the bowels. RSH were all hyperdense and in 8 cases (61%) a fluid-fluid level due to the hematocrit effect was noted. In one case, a retroperitoneal hematoma was discovered. The extension of the RSH was well delineated with MRI. The RSH showed itself with heterogeneous signal intensities with areas of high-signal-intensity on T1-weighted images. Fluid-fluid levels and a concentric ring sign were also noted. CONCLUSION: Older women with subcutaneous injection of heparin are especially prone to RSH even though there is no overall excessive activity of anticoagulant therapy. Clinical and biological diagnosis may be difficult. CT scan is the exam of choice to reach a precise and acute diagnosis of RSH.

Aged↗
PubMed1995

[Intracaval neoplastic thrombi from clear cell adenocarcinoma of the kidney involving the righ renal and spermatic veins. Report of a case].

The authors report the case of a patient with right renal cell carcinoma with two intracaval tumour nodules, one arising in the renal vein and the other arising in the spermatic vein. They discuss the complementary investigations and propose a pathophysiological explanation for this rare neoplastic extension to the spermatic vein.

Adenocarcinoma, Clear Cell↗
PubMed1995

[New imaging techniques in pulmonary embolism].

Acute pulmonary embolism is a medical emergency and diagnostic certitude must be obtained as early as possible. In clinically serious situations, spiral CT is a reliable diagnostic tool. It provides direct signs of embolism with visualisation of thrombi in the pulmonary arteries as far as the segmental branches and its diagnostic value does not change in cases of pulmonary parenchymal involvement. In emergencies, spiral CT should replace pulmonary angiography, which is more costly and associated with greater morbidity and mortality. Other methods, in particular MRI, which is totally innocuous, could play an important role in the diagnostic strategy of acute pulmonary embolism in the near future.

Diagnostic Imaging↗
PubMed1994

[Value of three-dimensional surface reconstruction scanning in urology. Preliminary results].

The development of helicoidal CT acquisition allows 3D reconstruction of vessels, cavities or parenchyma of mobile organs such as the kidney. The value of this 3D surface reconstruction was investigated in various areas of urology: congenital malformations (horseshoe kidney, megaureter, ectopic organs), acquired malformations (diverticulum, trabeculated bladder), renal stones, particularly staghorn calculi, and renal transplantation. The fields of interest of 3D CT scans are still poorly defined, but are probably threefold: diagnostic, therapeutic and for teaching purposes. 3D representation completes classical axial scans and, in some cases, competes with other more invasive imaging techniques.

Female↗
PubMed1994

[Qualitative and quantitative study of bone colonisation in a wired surface effect. An experimental study].

PURPOSE: The aim of this study was to evaluate the bony anchorage of a new implant (orderly wired surface effect with alloy Ti Al Va and ordered pores of 488 mu). Bony integration was analyzed on qualitative and quantitative aspects. MATERIALS AND METHODS: The implants were inserted into both femurs of six sheep in three localisations, in all 36 implants, during a period of 6 to 33 weeks. The implants were opposed on cortical bone or impacted into trabecular cancelous bone after corticotomy. Evaluation of rehabitation was realized using conventional radiography, MRI, isotopic study and particularly by computer assisted histomorphometry (BIOCOM program). This new technic evaluated the trabecular bone volume (TBV) of the implant, the trabecular bone density, and the mean trabecular width in real value with precision and objectivity. RESULTS: This study shows that there was good osteointegration of the implant, that this osteointegration differed with the localization of implantation. Quantitatively, the BIOCOM program showed that for metaphyseal implants in cancelous bone, the TBV of the implant was greater than that of the environment of the implant. DISCUSSION: It is questionable to speak of osteoinduction in an osteogenic situation but it is certain that in many implantation conditions, the TBV is more important in the implant than that of the environment surrounding the implant. This shows the excellent osteointegration of the implant. CONCLUSION: This implant brings a new concept of rehabitation space with its particular geometry of structure. This quality is confirmed by clinical experience with uncemented knee prosthesis.

Animals↗
PubMed1994

[Splenic arteriovenous fistula. Apropos of 2 cases and review of the literature].

Two cases of splenic arteriovenous fistula (SAVF) are reported and the literature pertaining to this disease is discussed. SAVF is a rare but curable cause of portal hypertension. Until recently, diagnosis was based and angiographic findings. However, it can now be reached with duplex-Doppler sonography, CT or MRI. Duplex-Doppler sonography highlights an enlarged splenic vein with a turbulent flow. CT scan detects the arterial aneurysms and shows the early opacification of the enlarged splenic vein. MRI depicts all the morphological abnormalities and flow-void due to time-of-flight losses may indicate the location of the fistula. Intra-arterial obliteration of the fistula is a good alternative to surgical procedure for treating SAVF in avoiding the potentially serious threat of gastrointestinal hemorrhage.

Adult↗
PubMed1994

[Acute postoperative renal insufficiency in renal transplantation. Incidence and risk factors].

Delayed renal function (DFG) is known to influence both the short and long-term outcome of transplanted kidneys. Data collected retrospectively on all 129 cadaveric renal transplants performed between January 1991 and January 1993 within a single center were analyzed. 42 (32.55%) cases of acute renal failure (ARF) occurred during the immediate postoperative period and 28 patients required dialysis. When compared with immediate good allograft function, DGF was associated with previous failed transplant (7/15 vs 35/114, p = 0.01), donor age (39.2 +/- 13 vs 30.1 +/- 12 years, p = 0.01), and episodes of collapsus of the donor (11/25 vs 31/104, p < 0.01). The graft function of the recipient was not correlated with the serum creatinine of the donor. There was no apparent relationship between the cold ischemia or the anastomosis time and the occurrence of DGF. One-year patient and graft survival were similar in the two groups (respectively for the group ARF and without ARF: 96.4% and 96.5%; 88.8% and 89%), but patients with DGF had higher serum creatinine values at 12 months post DGF (185.6 +/- 44.8 mumol/l vs 157.5 +/- 30.8 mumol/l, p = 0.06). This study suggests that DGF is related to the characteristics of the donor graft and is more frequently encountered in previously transplanted recipients.

Acute Kidney Injury↗
PubMed1994

[Diagnosis and percutaneous treatment of urinary collections and obstructions].

The collections encountered around the renal transplant are mainly lymphoceles, more rarely hematomas, abscesses and urinomas, the frequency of which constituting 12% of cases. Their diagnosis is usually made by sonography; the percutaneous puncture is guided by US or CT in order to define its nature and drain the cavity. Urinary obstruction (6% of the cases) may be detected by sonography or scintigraphy, but percutaneous pyelography is often required to confirm the obstruction, to precise its level and nature, and to guide the percutaneous procedure. In the case of urinoma (3% of the cases), ultrasound may be unclear and the urinary extravasation must be then confirmed by scintigraphy, postinjection delayed plain or CT scan films.

Abscess↗
PubMed1993

Limited T-cell receptor diversity in liver-infiltrating lymphocytes from patients with primary biliary cirrhosis.

Primary biliary cirrhosis is associated with the presence of high-titer anti-mitochondrial autoantibodies as well as T-cell infiltration of the liver, suggesting the involvement of autoimmune mechanisms. We have studied here the sequences of T-cell receptor alpha and beta chains expressed by T-cell clones derived from liver-infiltrating lymphocytes of two patients with primary biliary cirrhosis. Among the eight clones studied from the first patient, four expressed the same member of the V beta 6 subfamily, associated with either V alpha 4 (three clones) or V alpha 21 (one clone) gene segment. Two other clones expressed an identical V beta 12 transcript, and two in-frame alpha chain transcripts, involving V alpha 2 and V alpha 7 gene segments. From the second patient, eight out of the nine clones were found to rearrange V beta 17-J beta 2.1 and V alpha 3 gene segments. The remaining clone expressed distinct T-cell receptor chains, involving V beta 9 and V alpha 11 gene segments. As deduced from the analysis of their junctional regions, the eight T-cell clones expressing V beta 17/V alpha 3 gene segments derived from only three different T cells. Furthermore, conserved amino acid motifs were found to be encoded in both the alpha and the beta-chain junctional regions. Together, these data show a local amplification of unique T lymphocytes in both patients. The use of identical V beta J beta and V alpha gene segments with similar junctional sequences by three different cells, evidenced in one of the two cases, strengthens the view that liver-infiltrating T lymphocytes are selected locally by autoantigens in PBC.

Aged↗
PubMed1993

Direct coronal view of the shoulder with arthrographic CT.

Direct coronal oblique views of the shoulder were obtained with arthrographic computed tomography (CT) in 35 shoulders with surgical correlation. There were 18 complete cuff tears, four partial ones, two type 3 superior labral, anterior, and posterior (SLAP) lesions, and one type 4 SLAP lesion. The coronal sections were obtained after double-contrast shoulder arthrography and axial CT sections had already been obtained. The patient was seated directly on the slope of the gantry, and the shoulder to be studied was positioned in the center of the gantry. The maximal time needed for this procedure was 5 minutes. Rotator cuff tears were detected with a sensitivity of 95% and a specificity of 100%. The size of the tears as determined on the coronal sections was strongly correlated with surgical measurement (r = .939). All SLAP lesions were detected. The authors' experience shows that obtaining coronal oblique sections is an effective way to improve arthrographic CT.

Adolescent↗