Biomedical subjects

R Spielmann

Publications and source records attributed to R Spielmann.

13 recordsLinked to original sources

PubMed1999

Diagnostic potential of combined transthoracic echocardiography and x-ray computed tomography in suspected aortic dissection.

BACKGROUND: Transesophageal echocardiography (TEE) and magnetic resonance imaging (MRI) are considered optimal diagnostic methods in the setting of suspected aortic dissection. However, although less sensitive as single modalities, transthoracic echocardiography (TTE) and contrast-enhanced computed tomography (x-ray CT) are more widely available and less costly. HYPOTHESIS: This study was undertaken to compare the diagnostic performance and reliability of the combined use of TTE and x-ray CT with TEE and/or MRI findings in the setting of suspected aortic dissection. METHODS: The diagnostic power of combined TTE and x-ray CT was compared with both single use of TTE and x-ray CT and with TEE and/or MRI in a series of 168 consecutive patients with suspected aortic dissection (AD). Of these, 28 women and 58 men (mean age 53 +/- 16 years) underwent TTE and x-ray CT prior to TEE (n = 52) and/or MRI (n = 69). Diagnostic results of combined TTE/x-ray CT were retrospectively but independently reevaluated in blinded fashion; diagnostic findings were validated by angiography (n = 63), surgery (n = 52), or autopsy (n = 7). RESULTS: Type A dissection was found in 29 patients (34%), type B dissection in 10 (12%), whereas aortic dissection was excluded in 47 (55%). With 95%, the sensitivity of TTE and x-ray CT was significantly enhanced when used in a combined access compared with 67 and 79%, respectively, when used as single methods (95%; p < 0.05). Sensitivity and specificity (95 and 91%, respectively) of combined TTE/x-ray CT evaluation were not different from TEE and/or MRI (100 and 96%, respectively; NS). Thrombus formation, side-branch involvement, aortic regurgitation, pericardial effusion or mediastinal hematoma were also detected with similar sensitivities and specificities both by combined TTE/x-ray CT and TEE and/or MRI. CONCLUSION: This first controlled study comparing the combined information of TTE and x-ray CT with TEE and/or MRI revealed a similar diagnostic potential of both diagnostic strategies in the setting of suspected aortic dissection. Thus, in an environment with access to color Doppler TTE and x-ray CT only, the information from both tests should be combined to decide on diagnostic management of these patients.

Aortic Dissection↗

PubMed1999

MR-guided percutaneous excisional and incisional biopsy of breast lesions.

The aim of this study was the realisation and clinical application of MR-guided vacuum biopsy for percutaneous excisional and incisional biopsy of enhancing breast lesions. A breast biopsy system and procedure have been developed which allow precise and safe access to breast lesions in any location and use of vacuum biopsy (VB) under MR guidance. Fifty-one patients with 55 MR-detected lesions were examined. Verification of these diagnoses included re-excision histology of all 14 malignancies and for benign lesions retrospective correlation of histology and imaging, assessment of complete or partial removal of the enhancing area directly after VB (40 of 40 lesions) and follow-up MRI (33 of 40 lesions), which in contrast to conventional needle biopsy can be used as proof of representative removal. Fifty-four of 55 procedures (including 15 lesions </= 5 mm and another 26 lesions of 5-10 mm size) were successful. One failure was caused by incorrect use of the VB gun. Vacuum biopsy yielded 14 malignancies and 40 benign lesions. With the available verification techniques all diagnoses proved correct. Percutaneous VB became possible under MR guidance. With minimal invasion it allowed increased certainty and accuracy even for very small lesions.

Biopsy↗

PubMed1998

Critical evaluation of the specificity of MRI and TVUS for differentiation of malignant from benign adnexal lesions.

The aim of our work was to study the specificity of MRI in comparison with transvaginal US for differentiation of malignant from benign adnexal lesions. A total of 67 patients with clinically suspicious adnexal lesions were evaluated by MRI. Transaxial and coronal images were acquired using T1-weighted sequences before and following IV contrast and T2-weighted sequences. In all patients transvaginal ultrasound examinations (TVUS) were performed. For both imaging modalities each lesion was classified separately as either benign or malignant according to previously published criteria. Pathologic findings were available in 65 cases. Both MRI and TVUS correctly classified the 12 malignant lesions (sensitivity 100 %). Specificity (MRI: 78.2 %, TVUS: 65.5 %) and accuracy (MRI: 82 %, TVUS: 71.6 %) were higher with MRI than with TVUS, but differences were statistically not significant (p = 0.18 and p = 0.20, chi-square test). There was agreement/disagreement between findings of MRI and US in 52/15 lesions. The macroscopic criteria for malignancy are unspecific and result in a limitation of the specificity of both MRI and TVUS. The MRI technique is a valuable adjunct to TVUS by enabling further clarification of adnexal tumors with equivocal complex or solid vaginal sonographic findings.

Adnexal Diseases↗

PubMed1996

[Not Available].

Explore the source record for details and available documents.

Dental Instruments↗

PubMed1995

Positive selection of growth-inhibitory genes.

We have isolated a limited set of cDNAs that limit cell proliferation using a unique assay based on the dilution of a lipophilic fluorescent dye as transfected cells divide. The identification of growth-inhibitory factors has been limited by the lack of a strong assay for growth inhibitors. A growth-inhibited cell does not grow and so is at a selective disadvantage in vitro when compared with any growing cell. Several assays have been used to screen for growth-inhibitory genes; however, these approaches are either very difficult to implement, leaky, or not comprehensive. We have developed an assay that selects for cDNAs capable of inhibiting proliferation in which cells are nonspecifically labeled with a lipophilic fluorescent dye, PKH-2, and subsequently transfected with a cDNA library made from growth-inhibited cells. With each cell division, the amount of dye per cell is reduced by one-half. Over time, growth-inhibited cells will retain more dye per cell relative to actively growing cells. The population is then analyzed by fluorescence-activated cell sorting, and the brightest cells in the population are isolated. This assay has allowed us to select pools of cDNAs enriched for growth-inhibitory activities and may provide a general method for identifying growth-inhibitory genes active in varying biological contexts. We report here the successful application of the dye retention assay to the selection of cDNAs that inhibit epithelial cell proliferation.

Animals↗

PubMed1990

[The diagnostic value of MR tomography following gadolinium-DTPA compared to computed tomography in bladder tumors].

In a prospective study, 58 patients with carcinomas of the bladder were examined by CT and MRI; in 48, gadolinium-DTPA was administered intravenously. MRI provided exact staging in 89%, compared with 80% with CT. There was 13% over-staging with CT and 11% with MRI. MRI, unlike CT did not result in any under-staging. In 36 patients a quotient could be calculated from the signal intensity of the tumour and surrounding soft tissues both before and after the intravenous contrast medium and the increased quotient after contrast administration could be estimated. There was a significant increase in the tumour/muscle quotient with a mean of 72 +/- 22% (minimum 43%, maximum 153%), corresponding to a marked increase of the signal from the tumour when compared with the pre-contrast images. This had the following advantages compared with CT: accurate differentiation between superficial and intramural spread. MRI was better than CT at demonstrating tumours in the roof of the bladder and at the trigone.

Adult↗

PubMed1990

[Dissecting aneurysm of the thoracic aorta. Diagnosis--surgical management--results].

From 1980 to 1989, 84 patients underwent surgery for dissection of thoracic aortic aneurysms. According to the DeBakey classification there were 23 dissections of type I, 35 of type II and 26 of type III. Magnetic resonance imaging and combined transesophageal and transthoracic echocardiography are highly sensitive and specific methods for diagnosis and followup of aortic dissection. 10% of the patients had to undergo surgery again during the first 5 years. The 5-year-survival rate was 56.1% and the 10-year rate was 40.1%.

Adult↗

PubMed1988

Iodine-123 meta-iodobenzylguanidine scintigraphy: a noninvasive method to demonstrate myocardial adrenergic nervous system disintegrity in patients with idiopathic dilated cardiomyopathy.

Iodine-123 (I-123) meta-iodobenzylguanidine (MIBG) imaging was performed in 31 patients. Three patients were without cardiac disease and 28 had idiopathic dilated cardiomyopathy with various degrees of left ventricular dysfunction. The qualitatively assessed myocardial I-123 MIBG scintigrams and the myocardial versus mediastinal I-123 MIBG uptake ratio were related to I-123 MIBG activity and norepinephrine concentration determined from endomyocardial biopsy samples taken from the right side of the interventricular septum. Scintigrams and the MIBG uptake ratio were also related to plasma catecholamine concentrations, left ventricular ejection fraction and New York Heart Association functional class. Patients with distinct myocardial I-123 MIBG uptake (score 1) had a normal ejection fraction (58 +/- 16%). Patients with diffusely reduced uptake or scintigraphic defects (score 2) had a significantly lower ejection fraction (38 +/- 9%, p less than 0.05), whereas patients with shadowy or no visible myocardial uptake (score 3) had the lowest ejection fraction (23 +/- 6%, p less than 0.002 versus patients with score 2). The scintigraphically determined I-123 MIBG activity in the septal region correlated significantly with I-123 MIBG activity from the endomyocardial biopsy samples (r = 0.78, p less than 0.001, n = 9). The myocardial versus mediastinal I-123 MIBG activity ratio was significantly related to myocardial norepinephrine concentration (r = 0.63, n = 28) and to left ventricular ejection fraction (r = 0.74, n = 31). These data suggest that myocardial I-123 MIBG scintigraphy is a useful noninvasive method for the assessment of myocardial adrenergic nervous system disintegrity in patients with idiopathic dilated cardiomyopathy.

3-Iodobenzylguanidine↗

PubMed1988

Recovery of left ventricular function after myocardial infarction can be predicted immediately after thrombolysis by semiquantitative intracoronary thallium and technetium pyrophosphate scintigraphy.

The accuracy with which intracoronary thallium and technetium pyrophosphate scintigraphy during intracoronary thrombolysis predicts myocardial salvage was studied in 58 patients with acute myocardial infarction by comparing the acute scintigraphic findings with subsequent left ventricular function. Scintigrams obtained before and immediately after thrombolysis were interpreted by three independent observers using a scoring system. Regional wall motion in the infarct area was determined from left ventricular (LV) cine angiograms using the center-line method. Patients with mild hypokinesis (hypokinesis less than or equal to -2 SD from normal) could be distinguished from those with severe hypokinesis (hypokinesis greater than -2 SD) using the prethrombolysis thallium score with an accuracy of 83%. Accuracy using the post-thrombolysis score was 76%. When the post-thrombolysis thallium and technetium pyrophosphate scores were combined, differentiation was possible in 91% of all patients studied, and in 100% of patients with anterior myocardial infarction. Thus, analysis of combined thallium and technetium pyrophosphate scintigraphy accurately predicts recovery of LV function after thrombolysis and may be helpful in deciding whether acute percutaneous transluminal coronary angioplasty or bypass surgery should be performed after thrombolysis.

Cardiac Output↗

PubMed1988

[Thallium single photon emission computed tomography following thrombolysis: missing relation to left ventricular function].

To address the question of whether infarct size after thrombolysis can comparably be estimated by thallium SPECT scintigraphy and contrast cineangiography, 32 patients in whom regional wall motion abnormality had been assessed by means of the "centerline" method, 10 to 21 days after infarction, underwent biphasic thallium SPECT scintigraphy with dipyridamole. There were no statistically significant correlations between left ventricular ejection fraction and the degree of hypokinesia in the infarct area on one hand, and thallium defect size in the early and late scintigram on the other. Hypokinesia was inversely correlated (r = -0.51) with the time interval from symptom onset to reperfusion, but no such correlation was found between thallium defect size and this parameter. In patients in whom reperfusion was achieved within 3 h of symptom onset, hypokinesia was significantly less (-1.11 +/- 0.6 standard deviations (SD] than in patients in whom reperfusion was achieved later (-2.16 +/- 0.8 SD; p less than 0.01). Thallium defect size, however, was not different in these two groups of patients. It is concluded that there is no close correlation between regional wall motion abnormality assessed subacutely after thrombolysis and infarct size determined by SPECT in the chronic state. Thus, impairment of left ventricular function may not be assessed from scintigraphic findings.

Adult↗

PubMed1988

[Comparison of the acute hemodynamic effect of nisoldipine (Bay k 5552) and nifedipine in patients with ischemia-induced left ventricular impaired function].

Calcium channel blockers of the dihydropyridine type have different sites of action that may cause negative inotropic effects in some patients; therefore, their use as systemic vasodilators in left heart failure may be limited. In 10 patients with coronary heart disease we compared the acute peripheral and central hemodynamic effects of i.v. nisoldipine vs. i.v. nifedipine intraindividually, using a sequential crossover protocol. All patients were subjected to right heart catheterization, arterial pressure monitoring, and simultaneous radionuclide angiography. The infusion of either calcium channel blocker was titrated to a similar steady-state reduction of mean arterial pressure by 15 +/- 3% and 15 +/- 2%, respectively, which reduced systemic vascular resistance by 25 +/- 5% and 17 +/- 2%, respectively. The required equally effective dosage was 0.17 +/- 0.06 micrograms/min/kg for nisoldipine and 0.58 +/- 0.1 micrograms/min/kg for nifedipine. In contrast to nifedipine, the administration of nisoldipine was associated with an increase in cardiac index by 0.45 +/- 0.33 l/min/m2 (p less than 0.05), stroke volume index by 3.91 +/- 3.0 ml/m2 (p less than 0.05), and left ventricular ejection fraction by 4.6 +/- 2.8% (p less than 0.05). Mean pulmonary capillary wedge pressure decreased with nisoldipine from 11.8 +/- 3.4 to 8.0 +/- 3.4 mm Hg (p less than 0.005) and mean pulmonary artery pressure decreased from 20.4 +/- 4.06 to 16.1 +/- 3.2 mm Hg (p less than 0.005), but was unaffected by nifedipine. Left and right ventricular endsystolic and enddiastolic volumes were not significantly altered by either drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Lack of correlation after reperfusion between ventricular function and infarct size estimated by thallium single-photon emission computed tomography.

In 32 patients with acute myocardial infarction, who had undergone successful intracoronary thrombolysis, the results of regional wall motion measured from contrast cineangiograms 10 to 21 days after thrombolysis were related to the results of thallium single-photon emission computed tomography (SPECT) after intravenous dipyridamole. Wall motion was measured by means of the centerline method, and thallium defect size was estimated by comparing the patient's circumferential profile with that of 20 normals. No correlation was found between ejection fraction or regional wall motion and thallium defect size. The time from symptom onset to thrombolysis was inversely correlated with the degree of hypokinesis (r = -0.51) but not with thallium defect size. In patients treated within 3 hours, hypokinesis was significantly less than in patients treated later (-1.1 +/- 0.6 SD vs -2.2 +/- 0.8 SD, p less than 0.01) whereas thallium defect size was not significantly different in both groups. It is concluded that, in patients after thrombolysis, thallium defect size determined by SPECT does not reflect the degree of left ventricular dysfunction.

Adult↗

PubMedDate not supplied

Synergetic interpretation of patterned vasomotor activity in microvascular perfusion: discrete effects of myogenic and neurogenic vasoconstriction as well as arterial and venous pressure fluctuations.

Synergetic concepts allow to identify emergent coordination phenomena between interacting physiological systems, for example between the cutaneous microcirculation, the sympathetic nervous system and the cardiac and pulmonary systems. The temporal patterns (oscillations of various frequencies) that are found in the data obtained with laser-Doppler anemometers (LDA; e.g. Periflux 2 used in the study) can be investigated by simultaneous recording of photoplethysmographic data obtained in the identical region of interest, as well as in cutaneous regions treated with vasoparalytic procedures which permit to record the dynamics of the arterial system. These strategies were applied to studies in the cutaneous microcirculation (volar side of the index fingers) as well as to mucosal microcirculation (maxillar gingiva) in healthy subjects and in patients suffering from autonomic dysfunction (cutaneous microcirculation) or gingivitis. By this procedure, it could be corroborated that - contrary to popular notions - the temporal fluctuations in the LDA records do not necessarily reflect myogenic vasomotion, but can have multiple causes. In a confirming recent study [Schmid-Schönbein et al., J Auton Nerv Syst, 57, 136-140, 1996], we have demonstrated that the LDA fluctuations under conditions of normal ambient temperature and hand position most likely reflect neurogenic vasoconstriction. Under exceptional conditions, different patterns emerge. Prolonged exposure to ambient temperature (18 degrees C) leads to marked vasoconstriction, with occasional vasodilator escape ('miniature hunting reaction'). Normal subjects under gravitational load and in warm environment (28 degrees C ambient) silence their neurogenetic vasoconstriction reactions, which allows sinusoidal vasomotion to dominate. A similar phenomenon is seen in neuropathic patients at 21-24 degrees C (presumably due to structural defects). Fluctuations in LDA signal taken from the healthy gingiva are entrained to arterial, those taken from inflamed gingiva to respiratory activity. The theory and practice of nonlinear analysis is discussed, and data compression procedures allowing to portray characteristic temporal patterns for future diagnostic procedures are presented.

Autonomic Nervous System Diseases↗