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Biomedical subjects

B Brunot

Publications and source records attributed to B Brunot.

At least 19 recordsLinked to original sources
PubMed2003

[Pheochromocytoma in internal medicine: distinctive features and place of 123I MIBG scintigraphy].

PURPOSE: Pheochromocytoma diagnosis uses the localization of the tumour, particularly thanks to MIBG scintigraphy. The aims of this study were to evaluate the sensibility and specificity of this exam, his opportunity towards clinical and biological profile of patients with pheochromocytoma suspicion in Internal Medicine and towards others techniques of imaging. We tried to define the most effective and least expensive approach of pheochromocytoma diagnosis. METHOD: This study was carried out over 15 years period on 80 patients in Internal Medicine who underwent 123I MIBG scintigraphy for pheochromocytoma suspicion. RESULTS: Among the 80 patients who underwent 123I MIBG scintigraphy, only 18 suffered from a pheochromocytoma. A very few symptoms were specific, like the triad "headaches, sweating, palpitations" whose onlyone third of patients was concerned by. The diagnosis approach carried on with urine catecholamine measurement, who was specific when metanephrines were increased whatever their levels and when normetanephrines were higher or equal than 1,5 time the norme. Then, abdominal CT or MRI scanning and 123I MIBG scintigraphy were performed for localization of the tumor. The sensibility of scintigraphy was 83%, its specificity was 89%. That is comparable with other studies about 131I MIBG. CONCLUSION: Prescription of MIBG scintigraphy in Internal Medicine appears to be excessive: 77,5% of patients don't have a pheochromocytoma. It is related to the lack of specific symptoms, the wrong positives in urine normetanephrines measurement and the discovery of incidentaloms by CT scanning. The scintigraphy should be used like a topographic and not a diagnosis exam.

3-Iodobenzylguanidine↗
PubMed2003

Functional evaluation by quantitative dimercaptosuccinic Acid scintigraphy after kidney trauma in children.

PURPOSE: Most pediatric surgical teams have adopted nonoperative treatment for a traumatic kidney lesion in children. In the emergency setting and at long-term followup dimercaptosuccinic acid (DMSA) scintigraphy enables us to identify the consequences on global renal function as well as on the function of each individual kidney. MATERIALS AND METHODS: Eight boys and 12 girls between 0.6 and 15.9 years old (average age 9.7) were evaluated after including renal trauma, minor and major injury in 10 each. Scintigraphy was performed 8 days and 6 months after injury. The tracer used was 2 MBq./kg. Tc-DMSA. Semiquantitative analysis of the images consisted of determining 2 parameters, namely relative renal function, corresponding to the fraction of activity of a single kidney compared to the activity of the 2 kidneys, and the calculated renal activity fraction, corresponding to the function of each kidney compared with the activity of a theoretical kidney in a child of the same age. The posttraumatic renal scintigraphy series was paired with a series of healthy children matched by age, weight, height, sex and affected side of function as a control group. Global renal function was also measured using a formula based on ethylenediaminetetraacetic acid scintigraphy with the height, weight and increased serum creatinine in each patient. RESULTS: For minor injuries the quantitative functional evaluation revealed a significant average loss of renal function +/- SD on the side of the lesion (12.8% +/- 3.1% versus 18.3% +/- 2%, p = 0.001). For major injuries on relative renal function evaluation we noted an average 36-point difference in the damaged and contralateral kidneys 8 days after the accident. Six months after trauma we noted a definitive loss of 48% in the calculated renal activity fraction on the side of the lesion. There was no compensatory hypertrophy on the noninjured side when the calculated renal activity fraction was compared with that of a normal kidney in a control patient (mean 19.1% +/- 4.2% versus 19.5% +/- 3.7%, not significant). Creatinine clearance was normal in each patient. DISCUSSION A renal contusion always induces parenchymal loss. Major kidney trauma has significant consequences on the opposite side. At 6 months the presumably uninjured contralateral kidney may be limited in its ability to compensate through hypertrophy, which worsens the global renal functional prognosis of a traumatic but initially unilateral lesion. CONCLUSIONS: Posttraumatic functional evaluation by DMSA scintigraphy, which measures the nephron capital of each kidney and the 2 together, seems essential to inform patients about the seriousness of the lesion and lead them to an eventual long-term nephrological followup with regular blood pressure assessment.

Adolescent↗
PubMed1997

Myocardial perfusion and function imaging at rest with simultaneous thallium-201 and technetium-99m blood-pool dual-isotope gated SPECT.

UNLABELLED: We present a simultaneous gated SPECT (G-SPECT) dual-isotope technique using 201Tl for perfusion and 99mTc blood-pool labeling for function imaging. METHODS: Seventeen patients (13 with previous myocardial infarction, MI) and a control group of three normal volunteers were investigated. They received, 15 min after a 201Tl stress/redistribution protocol with reinjection, 900-950 MBq 99mTc-HSA for blood-pool labeling. Eight frames per R-R interval were recorded in the G-SPECT mode with three windows: window A with 20% centered at 71 keV for 201Tl, window B with 10% centered at 105 keV for Tc scatter contamination and window C centered at 140 keV with 20% for 99mTc. Nongated, crosstalk-corrected 201Tl SPECT perfusion images were reconstructed according to normalized projection-by-projection subtraction from data from windows A and B. G-SPECT data from window C were reconstructed with the same reconstruction limits to allow topographic correlations of left ventricular perfusion and wall motion abnormalities. Polar maps of perfusion and function were used to divide the myocardium into 20 segments. Perfusion was expressed as the percentage of thallium uptake and function corresponding to diastolic to systolic shortening normalized by end diastolic volume. RESULTS: Segmental comparison of uncontaminated-to-contaminated and corrected 201Tl patient images demonstrated an overall agreement score of 93%, with a kappa statistic of 0.76 +/- 0.06 when normal perfused segments were excluded. Segmental matching of perfusion against function at rest showed no correlation for the 10 patients with preserved ejection fraction of 59% +/- 8% nor for the control group. For the remaining seven patients with an ejection fraction of 34% +/- 10%, there was linear correlation between perfusion and function (r2 = 0.61). CONCLUSIONS: The feasibility of dual TI-Tc G-SPECT was examined at rest and suggests low perfusion hypokinesis that matches linear dependence for CAD patients with low ejection fraction.

Adult↗
PubMed1996

Diversion of salivary flow to treat drooling in patients with cerebral palsy.

The authors performed six sialodochoplasties between 1991 and 1994 to treat drooling in six children who suffered from cerebral palsy. There were three boys and three girls, aged 13 to 22 years (mean, 16 years). All patients underwent parotid duct rerouting. The first four patients (group I) also underwent associated excision of submandibular ducts, and the last two patients (group II) benefited from rerouting of the submandibular ducts. In group I, results were considered good in two cases, fair in one case, and poor in one case. A fistula of the new Stenon duct appeared in one patient, which required excision and ligation followed by progressive involution of the parotid gland. Both group II patients had excellent and rapid results. The requirements leading to surgical decision are determined. The importance of physiotherapy is emphasized. Surgical techniques are described and discussed, as are objective criteria for the assessment of surgical results, namely salivary radioisotopic scanning.

Adolescent↗
PubMed1996

[Interventional MRI. Value of low field strength and very fast 3D steady state imaging sequences for the guidance of a "non" ferromagnetic needle].

PURPOSE: The excellent tissue differenciation provided by MRI in the three directions and the lack of ionizing radiations make it ideal for interventional procedures. Many problems must still be solved: the access to the patient, the size of the artefact produced by interventional instruments and the acquisition time. In this study, we evaluated the influence of field strength for standard imaging sequences on the MRI artefact of a non ferro-magnetic biopsy needle. Then, we developed very fast sequences on a opened 0.1 T dedicated magnet to test in vitro and ex vivo the potential ability of this system in the guidance of the needle. MATERIAL AND METHODS: The biopsy needle was a new stainless steel needle made of 49% Nickel. The needle artefact's size measurements were made at 0.1 T, 0.5 T and 1 T on a bicompartmental phantom (one compartment with a long T1 and another with a long T2), with standard gradient echo (400/12/90 degrees) and spin echo (500/25) sequences. At 0.1 T, we optimized very fast steady state 3D FAST (T1 weighted) and 3D CE-FAST (T2 weighted) sequences to reduce the acquisition time, preserving good image contrasts for a field of view reaching 38 mm and 48 x 64 or 24 x 32 matrix. RESULTS: The larger needle artefact observed on gradient echo images varied from 3.6 mm at 0.1 T to 8.6 mm at 1 T. The shortest acquisition time for 4 contiguous slices of 2mm with a 1.2 mm/pixel resolution and a 24 x 32 matrix was 1.5 s for the 3D FAST (16/9/65 degrees) sequence and 3 s for the 3D CE-FAST (29/22/65 degrees) sequence. We realized a complete MRI guided abdominal puncture on a cat cadaver with 4 series of 15 s 3D FAST images (16/9/65 degrees, 4 slices, 5 excitations, 1.2 mm/pixel, FOV = 77 mm). Besides the cat positioning and the image reconstruction time, the whole puncture lasted 1 min (4 x 15 s). CONCLUSION: Low field MRI (0.1 T) combined with very fast 3D steady state sequences is adapted for the real time guidance of biopsy needles.

Biopsy, Needle↗
PubMed1995

Auxiliary liver transplantation for fulminant and subfulminant hepatic failure.

We report the first series of 9 auxiliary liver transplantations performed as a bridge to recovery in 8 patients with fulminant and subfulminant hepatic failure. Hepatic failure was due to hepatitis A virus (n = 3), hepatitis B virus (n = 1), hepatotoxic drugs (n = 2), autoimmune disease (n = 1), or it was of unknown origin (n = 1). The donor liver was reduced to a left lobe (n = 2), a left liver (n = 4), or a right liver (n = 3), and was implanted in an orthotopic position beside the native liver after it was resected by a left or a right hepatectomy. Conventional immunosuppression was used to prevent rejection. Six patients regained normal consciousness within 2 weeks, without any sequelae. Two patients had persisting encephalopathy due to graft initial dysfunction, one of whom showed portal vein thrombosis, which was successfully cleared. The other one showed hepatic vein stenosis and was retransplanted at day 15. Five of eight patients had to be reoperated because of a surgical complication. Five patients showed rapid regeneration of their native liver, but one died at day 45 from severe herpes virus broncholitis. The auxiliary grafts were removed (n = 3) or left to atrophy by tapering immunosuppression (n = 1). One patient developed cirrhosis of the native liver and died of infectious complications at day 42. The native livers of the two remaining patients are still atrophic, one at 4 months and one at 1 month posttransplant. Finally, 6 of 8 patients are alive with a follow-up of 1 to 17 months. Four of them have permanently stopped their immunosuppressive therapy. Our experience demonstrates that auxiliary orthotopic liver transplantation (1) is feasible in children and adults, using either a left or a right liver graft, (2) is efficient in providing adequate liver function, and (3) gives a real chance to the native liver to regenerate, offering these patients a future free of immunosuppression.

Adolescent↗
PubMed1995

An in vitro study at low field for MR guidance of a biopsy needle.

The aim of this study is to demonstrate in vitro that low field strength can be used for MR interventional procedures. At 0.1 T, we developed 3D, T1-, and T2-weighted fast steady state sequences and measured the artifact created by an MR biopsy needle (22 gauge, 0.7 mm diameter) on a bicompartmental phantom. The artifact generated by the needle placed perpendicular to B0 did not exceed 3.6 mm for 3D steady state sequences and acquisition times reaching 1.5 s. Corresponding artifacts at higher field strength were 7.6 mm for 0.5 T and 8.6 mm for 1 T. Low field MRI proved to be potentially adaptable for the guidance of MR biopsy needles.

Artifacts↗
PubMed1994

Detection of glomus tumor of the finger by dedicated MRI at 0.1 T.

Three glomus tumors of the fingers were detected using a dedicated hand and wrist low field (0.1 T) MR imager equipped with solenoidal coils allowing a FOV of 2 cm. Three-dimensional T1-, T*2-, or T2-weighted images were used (8 contiguous slices of 2 mm thickness). Glomus tumors had low or intermediate signal intensity (2 cases) or no signal (1 case) on T1-weighted images. On T*2- or T2-weighted images they had high signal intensity. MRI findings correlate well with surgery and biopsy.

Adult↗
PubMed1994

A study of cerebral perfusion using single photon emission computed tomography in neonates with brain lesions.

In this study we used a single photon emission computed tomography technique (SPECT) with radiolabelled 99mTcHMPAO to assess cerebral perfusion in newborn infants with documented cerebral lesions and to determine to what extent brain SPECT might be useful in the neonatal period. A total of 15 newborn infants with the following cerebral pathologies were enrolled: severe parietal bilateral periventricular leucomalacia (PVL, n = 6); moderate parietal bilateral PVL (n = 2); intraventricular haemorrhage grade II with unilateral parietal parenchymal extension (IHV + PE, n = 3); cerebral infarction (CI, n = 2) in the zone of middle cerebral artery; and post-haemorrhagic hydrocephalus (n = 2). Follow-up was available in all infants. Alterations in cerebral perfusion were seen in only 12 of 15 infants and at the location of severe PVL, PE and CI. We have noted that the regions of diminished perfusion extended beyond the apparent extent of cerebral pathology delineated by ultrasound or magnetic resonance imaging. Markedly diminished perfusion was seen in 1 infant with hydrocephalus, which recovered following placement of ventriculo-peritoneal shunt. Regarding outcome, SPECT data failed to provide additional information than that of neuroradiological investigations. We conclude that the use of SPECT, under these conditions, to assess alteration of cerebral perfusion in the neonatal period will not provide any additional information than that of neuroradiological investigations.

Brain↗
PubMed1994

Cerebral perfusion studies during maturation using single photon emission computed tomography in the neonatal period.

In this study, we used single photon emission computed tomography (SPECT) radiolabelled 99mTc HMPAO to assess cerebral perfusion during maturation in the neonatal period. Results of SPECT examinations in 18 newborn infants, in whom gestational age ranged form 30 to 41 weeks, and who were found to be neurologically normal in retrospect, were reviewed. The developmental changes in cerebral perfusion during the neonatal period shown by SPECT parallel findings of other methods on maturational changes of the central nervous system (neuropathological studies, positron emission tomography scan, magnetic resonance imaging). Cerebral perfusion progresses from the central part of the brain to the cerebellum, sensorimotor and then visual cortex. A close relation seems to exist between cerebral perfusion, metabolism and behavior under normal conditions in the neonatal period.

Brain↗
PubMed1994

Biopsy and quantitative hepatobiliary scintigraphy in the evaluation of liver transplantation.

METHODS: Hepatobiliary scintigraphy with technetium-99m-mebrofenin including a first-pass study of 60 two-sec images and a functional phase of 40 one-min images was performed in 26 patients (42.5 +/- 12.5 yr) in the early postoperative period (9.1 +/- 4.3 days) after liver grafting. Needle biopsy was carried out within a mean of 0.5 +/- 2.2 days of the scintigraphy study. Considering only rejection and cholestasis, biopsy results were used to classify the patients in three groups: control group I (11 patients) with minimal lesions, group II (9 patients) with moderate histologic modifications, and group III (6 patients) with severe dysfunction showing important structural changes. First-pass time-activity curves were used to calculate arterial (alpha-A) and portal (alpha-P) angles as well as a portal perfusion index. Functional time-activity curves were used to define two blood retention indices (BRI1 and BRI2) and two liver uptake indices (LUI1 and LUI2). Excretion was not quantified. RESULTS: Simple linear regression analysis showed a significant correlation between portal perfusion index and BRI1 (p < 0.05, r = -0.43) and BRI2 (p = 0.01, r = -0.53). The validity of the histologic classification was assessed by the existence of significantly different (p < 0.05) mean values for alpha-P, portal perfusion index and LUI1 in the three groups. All other indices could distinguish significantly between groups I and II. Furthermore, arterial angle alpha-A allowed differentiation of group II from group III but not group I from group II; on the contrary, LUI2 and BRI1 distinguished group I from group II but not group II from group III. CONCLUSION: This study demonstrated a close correlation between early biopsy results and perfusion indices in patients with a liver graft as well as uptake parameters determined by hepatobiliary scintigraphy.

Adult↗
PubMed1992

High resolution MRI of the normal finger at 0.1 T: anatomic correlations.

MR images of the fingers are obtained in a 128 x 128 or 256 x 256 matrix format using a prototype of a mini imager dedicated to the hand. The vertical field of 0.1 T is provided by an electro-magnet with an air gap of 15 cm equipped with a single solenoidal coil. No Faraday cage is used. The maximum in plane pixel resolution of 100 mu is obtained for a field of view of 2.5 cm with a slice thickness of 2 mm. The identification of fine structures of the finger is demonstrated by the anatomical and histological correlations. This type of imager which is adapted to very limited field of views demonstrate that high resolution MRI of limb extremities can be achieved at 0.1 T.

Fingers↗
PubMed1992

MRI of hand and wrist with a dedicated low field mini imager: preliminary report.

In this paper we describe the development and the early results of an MRI system designed specifically for imaging of the hand and wrist. The imager takes up little space, uses a small 0.1 Tesla water-cooled electro-magnet with a vertical magnetic field and a 15 cm air gap. The system is based on a PC micro-computer and an integrated image processing board. There is no need for a Faraday cage. The image resolution is less than 1 mm using a 128 x 128 matrix format for a typical slice thickness of 3 mm. It is possible to achieve a 0.2 mm per pixel spatial resolution when imaging the fingers.

Hand↗
PubMed1992

Increase in radionuclide left ventricular ejection fraction after cardioversion of chronic atrial fibrillation in idiopathic dilated cardiomyopathy.

To assess the potential improvement in left ventricular ejection fraction after cardioversion of chronic atrial fibrillation to sinus rhythm in idiopathic dilated cardiomyopathy, we studied prospectively 17 patients, aged 58 +/- 6 years, by radionuclide angiocardiography at rest. Left ventricular ejection fraction was determined before treatment and at a mean delay of 4.7 months after cardioversion. Return to sinus rhythm was obtained in 12 patients, pharmacologically or by electrical cardioversion. Five patients remained in atrial fibrillation. No clinical, echocardiographic or haemodynamic finding could predict the success of cardioversion. In chronic atrial fibrillation, the ejection fraction did not change significantly: 30.0 +/- 9.1% (19 to 44%) at the first evaluation and 29.5 +/- 8.3% (22 to 41%) after 4.7 months. After successful cardioversion, left ventricular ejection fraction improved from 32.1 +/- 5.3% (24 to 41%) to 52.9 +/- 9.7% (37 to 71%) (P less than 0.001). The difference was 20.8 +/- 11.3% and left ventricular ejection fraction was normalized in 50% (6/12) of the patients. There was a significant reduction in the cardiothoracic ratio on chest X-rays and of the left ventricular end-diastolic diameter on echocardiography; fractional shortening increased (27.7 +/- 4.3% vs 20.3 +/- 2.7%, P less than 0.01). A third evaluation was realized after a mean delay of 11.7 months in the patients with successful cardioversion. Sinus rhythm was present in 83% (10/12) of the patients: seven patients were reevaluated by radionuclide angiography. The improvement in left ventricular function observed at the 4.7 months evaluation was still present. In two patients with recurrence of atrial fibrillation, there was a severe deterioration of left ventricular systolic function.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

MR imaging of hand and wrist with a dedicated 0.1-T low-field imaging system.

We describe the first results of a new magnetic resonance imaging (MRI) system specially developed for hand and wrist imaging. The system uses a small resistive water-cooled magnet with a vertical magnetic field of 0.1 T in an air gap of 15 cm. The console is based on a microcomputer with a vector signal processor and an image-processing board. There is actually no Faraday cage. For the whole hand, the in-plane spatial resolution is less than 1 mm in the 128 x 128-pixels format for typical slice thicknesses of 3 to 5 mm. Solenoidal volume coils for fingers were developed, giving, in the same matrix format, an in-plane high spatial resolution of 0.22 mm for a typical slice thickness of 3 mm.

Hand↗
PubMed1991

[Congestive heart failure with intact systolic function].

A retrospective study was undertaken of the cases of patients admitted for congestive cardiac failure over a 4 year period, and investigated by radionuclide angiography to determine the prevalence of cardiac failure with normal left ventricular systolic function, to document the underlying mechanisms of this condition and to assess whether the clinical data could predict the presence or absence of left ventricular systolic dysfunction. After excluding patients with significant valvular disease, severe renal failure, or myocardial infarction in the previous 2 months, the study population comprised 152 patients divided into 2 groups: Group I (N = 112) with abnormal systolic function (radionuclide ejection fraction less than 45%) and Group II (N = 40) with normal systolic function (radionuclide ejection fraction greater than or equal to 45%). The clinical, echocardiographic and radionuclide angiographic data was analysed (global ejection fraction in both groups and peak filling rate in Group II). The patients in Group II (26% of the total study population) were older (66.5 +/- 12.4 vs 61.3 +/- 12.3 years, p less than or equal to 0.02), were more often female (35% vs 17.9%, p less than or equal to 0.02), had acute cardiac failure (75% vs 37%, p less than 0.00001), and were frequently hypertensive (65% vs 39%, p less than or equal to 0.005). Univariate analysis of clinical and radiological signs did not show any significant difference between the two groups except for increased jugular venous pressure and cardiomegaly which were more common in Group I (56% vs 25%, p less than 0.00001 and 93% vs 68%, p less than or equal to 0.00001, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗