PubMed Health⌕ Search

Biomedical subjects

W Neff

Publications and source records attributed to W Neff.

14 recordsLinked to original sources
PubMed2007

[Neoadjuvant chemotherapy of breast carcinomas: what post-therapeutic (preoperative) information is provided by quantitative dynamic MRI?].

PURPOSE: The aim of this study was to evaluate whether quantitative changes in contrast enhancement (CE) after neoadjuvant chemotherapy (NC) are associated with histological signs of tumor regression and whether quantitative dynamic MRI (dMRI) is capable of accurately assessing preoperative tumor size compared to mammography (MG) and ultrasound (US). METHODS: Thirty-one patients with breast cancer underwent MRI before and after NC. Dynamic CE was measured using a turbo-FLASH sequence and quantified by a two-compartment model, where two parameters, k(ep) (distribution constant rate) and A (amplitude), were calculated and color mapped. RESULTS: When tumors had signs of histological regression in the operative specimen (n=17) decrease of the parameters A and k(ep) was significantly more marked compared to tumors without regression (n=12). The correlation between tumor size measured by dMRI and histopathology was 0.81 when areas of unspecific CE were included; when they were not included the correlation was 0.66 and tumor size was systematically underestimated. In 26 patients dMRI was retrospectively compared with MG (r=0.51; dMRI, r=0.80) and in 22 patients with US (r=0.60; dMRI, r=0.75). CONCLUSION: Changes in dynamic CE are associated with histological tumor regression. Quantitative dMRI enables a valid assessment of tumor residue and is superior to MG and US. Remaining unspecific CE within the original tumor site should be considered as potentially malignant.

Breast↗
PubMed2005

[Fetal surgery].

Fetal surgery is a newly evolving multidisciplinary medical field, being performed in specialized centers. It deals with the treatment of selected fetuses with congenital anomalies that cause high morbidity and mortality. The aim of the surgical treatment is to avoid the development of progressive and eventually irreversible damage at birth. Examples of entities treated are obstructive uropathy leading to renal insufficiency, lung hypoplasia in severe congenital diaphragmatic hernia, severe congenital cystic adenomatoid malformation of the lung, and sacrococcygeal teratoma. This review describes principles of fetal surgery, physiopathologic processes of some of the anomalies treated in this way, and diagnostic and therapeutic approaches. Recently published results are presented and discussed.

Coccyx↗
PubMed2005

Midwall myocardial fibrosis in Becker-Kiener muscular dystrophy.

We report on a 38- year-old man with Becker-Kiener muscular dystrophy (BMD) and dilated cardiomyopathy without clinical symptoms of congestive heart failure who was referred for risk evaluation of sudden cardiac death. The degree of cardiac involvement in BMD varies greatly from no or hardly any cardiac abnormality to severe arrhythmias, dilatative cardiomyopathy and heart failure to heart transplantation or sudden cardiac death. These cardiac abnormalities have been related to replacement of the cardiomyocytes by connecting tissue or fat. In the clinical setting, cardiovascular magnetic resonance (CMR) has been proved to be a valid non-invasive method for obtaining anatomical and structural information of the heart. Furthermore, gadolinium-enhanced CMR can also characterize areas of myocardial fibrosis. Demonstration of extensive areas of fibrosis in an early stage of the disease might be a surrogate marker for an impaired clinical outcome. Therefore, serial CMR examinations starting upon diagnosis of the disease should be considered, as this may lead to an earlier recognition of cardiac involvement and may affect further management of the patient.

Adult↗
PubMed2004

Evaluation of extracranial-intracranial arterial bypass function with magnetic resonance angiography.

Extracranial-intracranial (EC/IC) arterial bypass surgery is a valuable therapeutic modality in the field of cerebrovascular surgery. The assessment of bypass patency and its functional parameters are of utmost importance in the postoperative course. The present study examined the potential role of quantitative MR-based volume flow measurement techniques for the investigation of bypass patency. Forty-one patients with steno-occlusive cerebrovascular disease treated with EC/IC bypass surgery underwent conventional angiographic (CA) and two-dimensional cine-phase MR-based angiographic assessment (MRA) of bypass function. CA bypass function was evaluated as poor (grade I), moderate (grade II), or extensive (grade III) and was compared with quantitative volume flow measurements (BVF) obtained in MRA studies. Bypass filling was classified as grade I in 15% of the cases, grade II and grade III in 36% and 49% of the studies, respectively. Mean BVF differed significantly in the different grades: 31.94 +/- 9.8 ml/min in grade I, 73.6 +/- 16.7 ml/min in grade II, and 97.2 +/- 26.6 ml/min in grade III. BVF values of 48 ml/min or lower (n = 6) were specific for grade I bypass function, while only BVF values higher than 111 ml/min (3/20, 15%) are specific for extensive angiographic bypass function. The assessment of EC/IC bypass patency with quantitative BVF measurements provides exact, investigator-independent information under physiological conditions. MRA is well correlated with the angiographic bypass grading system.

Aged↗
PubMed2001

[Diagnosis of pancreas tumors: MRI or multidetector spiral CT?].

Recent technical advances in the field of abdominal MRI and multi-detector spiral-CT (MSCT) have resulted in improved diagnostic capabilities of pancreatic tumors. Preliminary data demonstrate slight advantages of MRI in the detection of liver metastases and papillary tumors as well as in the differential diagnosis of pancreatic masses while MSCT might be advantageous in the assessment of vascular infiltration, particular in uncooperative patients.

Diagnosis, Differential↗
PubMed2000

Pulse-inversion contrast harmonic imaging: ultrasonographic assessment of cerebral perfusion.

Pulse-inversion contrast harmonic imaging is a new ultrasonographic technique that can assess brain perfusion. In an adult with moyamoya disease and multiple recurrent strokes, this method detected subtle hemispheric differences in temporal-lobe perfusion, presumably due to neovascularisation, which were not shown by xenon-computed tomography or magnetic resonance perfusion imaging.

Adult↗
PubMed2000

Pancreas picture of the month. Pancreatic manifestation of cystic fibrosis.

The Magnetic Resonance Cholangio Pancreatography (MRCP) provides within a few seconds complete information on cystic degeneration of the pancreas in patients with cystic fibrosis. The authors present a case report of cystic fibrosis with a pathognomonic magnetic resonance cholangio pancreaticography image of the pancreas.

Adolescent↗
PubMed1998

Spontaneous healing of cervical pseudoaneurysm in vertebral artery dissection under anticoagulant therapy.

We report a 41-year-old woman with embolic stroke of the mid-pons attributed to embolism from vertebral artery dissection. Angiography revealed an occluded artery on one side and an incidental pseudoaneurysm of the midcervical portion of the vertebral artery on the other. After 3 months of warfare in therapy control angiography showed complete occlusion of the pseudoaneurysm. We discuss therapeutic choices and review the literature.

Adult↗
PubMed1998

Cranial nerve syndrome in thrombosis of the transverse/sigmoid sinuses.

Cerebral venous thrombosis (CVT) is a cerebrovascular disease associated with a wide variety of clinical signs and symptoms, which may often delay appropriate diagnosis. Single or multiple cranial nerve palsies (III-VIII) without evidence of other signs and symptoms have not, so far, been considered a relevant syndrome of CVT. This event turned out to be a characteristic finding in five patients with thrombosis of the ipsilateral transverse/sigmoid sinus, who were recruited prospectively over a 14-month period. The diagnosis was supported by non-invasive MRI with the application of a newly developed subtraction technique. In view of the considerable mimics of the syndrome, and the long-standing need for conventional angiography to confirm the disease, it is likely to have been underestimated in the past; since appropriate treatment seems possible the diagnosis and utility of early MR venography should be considered in patients with single or multiple cranial nerve lesions of uncertain aetiology.

Adult↗
PubMed1996

Ischemia-induced migraine from paradoxical cardioembolic stroke.

Although little is known on the pathophysiologic mechanism of migraine-related stroke, the prevailing attitude is that vasoconstriction and activation of clotting factors play a primary role. In 2 female patients presenting with migraine and stroke, risk profiles and history were consistent with this pathophysiologic mechanism. Cerebro- and cardiovascular workup, however, led to a diagnosis of paradoxical cardioembolic stroke through a patent foramen ovale. Since there is hardly any evidence in the literature that migraine acts as a risk factor for stroke on its own, these case reports emphasize the importance of complete cardiovascular evaluation in patients with suspected migrainous stroke.

Adolescent↗
PubMed1996

Assessment of regional cerebral blood volume in acute human stroke by use of single-slice dynamic susceptibility contrast-enhanced magnetic resonance imaging.

BACKGROUND AND PURPOSE: The purpose of this study was to evaluate the clinical usefulness of dynamic susceptibility contrast-enhanced MRI (DSC-MRI) in acute cerebral ischemia. METHODS: During bolus injection of gadolinium-diethylenetriamine pentaacetic acid, a series of rapid T2*-weighted images was recorded from one slice. Concentration-time curves and images of regional cerebral blood volume (rCBV) were calculated from this data set. DSC-MRI, MR angiography, conventional spin-echo MRI (SE-MRI), and CT were performed in 11 patients within 6 hours after stroke onset and before thrombolytic or anticoagulant treatment was begun. A follow-up MRI examination was performed 24 to 48 hours after stroke onset. RESULTS: In 7 of 11 patients (group 1) with territorial infarcts of the middle (n = 6) or posterior cerebral artery (n = 1), DSC-MRI showed reduced rCBV in the affected territory before conventional SE-MRI displayed ischemic lesions. DSC-MRI was helpful to differentiate severely ischemic tissue from peri-infarct parenchyma. Partial reperfusion (n = 3), unchanged reduction of rCBV (n = 2), and progressive reduction of rCBV (n = 2) were observed in the follow-up study. Normal DSC-MRI findings were present in 4 of 11 patients (group 2) with lacunar infarcts. CONCLUSIONS: DSC-MRI accomplished the detection of the ischemic territory in the very early stage (< 6 hours) before SE-MRI delivered unequivocal results. DSC-MRI might be helpful to discriminate completely ischemic tissue from potentially salvageable ischemic parenchyma at risk and may play an important role in stroke therapy and evaluation.

Aged↗
PubMed1995

New and future developments in cerebrovascular ultrasound, magnetic resonance angiography, and related techniques.

Four-dimensional (4D) analysis of atherosclerotic plaque and wall motion, the application of 4D ultrasound to the study of atherogenesis, and the incorporation of ultrasound data into flow models for simulation of cerebrovascular hemodynamics are new frontiers in diagnostic ultrasound that use computer vision and optical flow techniques to exploit the full potential of real-time imaging and Doppler studies. New approaches to improve blood vessel delineation with ultrasound include application of contrast agents, harmonic imaging, and red blood cell density imaging. An assessment of the potential clinical utility of these new developments in cerebrovascular ultrasound requires an analysis of comparable trends in magnetic resonance (MR) technology, eg, rapid advances in the fields of MR angiography, dynamic contrast-enhanced MR, and MR diffusion imaging. Likewise, the value of ultrasound techniques for the measurement of blood flow to evaluate cerebrovascular hemodynamics must be compared to related methods in magnetic resonance, such as dynamic MR inflow tracking. This article addresses several new and future developments in cerebrovascular ultrasound and discusses their relative merits in terms of ongoing research in the field of magnetic resonance angiography, imaging, and related techniques.

Blood Flow Velocity↗
PubMed1980

[Percutaneous catheter dilatation of carotid stenoses --animal experiments (author's transl)].

Thirty-one carotid artery stenoses were produced in thirty dogs by three different techniques. Twenty-three of these could be cured by transfemoral percutaneous catheter dilatation. High grade tight stenoses may present resistance which cannot be overcome by the catheter. Histological examination of the dilated vessels showed circumscribed changes in the vessel wall, with destruction of elastic membranes. From our experience of catheter dilatation of pelvic and lower limb arteries and of renal arteries, we consider it feasible to use this technique in selected patients with carotid stenosis.

Angiography↗