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Biomedical subjects

E Merkle

Publications and source records attributed to E Merkle.

At least 19 recordsLinked to original sources
PubMed2000

[Contrast enhanced power Doppler sonography: comparison of various administration forms of the ultrasound contrast agent Levovist].

PURPOSE: Objective of the present study was the comparison of various administration forms of the ultrasound contrast medium Levovist with regard to duration and intensity of contrast enhancement in patients with tumors of the liver or pancreas. PATIENTS AND METHODS: Seven patients with tumors of the liver or pancreas were examined prospectively using power Doppler sonography. Ultrasound contrast enhancement was achieved using Levovist (8 ml, 400 mg/ml) in three different administration forms: 1st as a bolus injection through the main channel, 2nd through the injection valve of an intravenous cannula, or 3rd as a continuous infusion. Semiquantitative evaluation of the degree of contrast enhancement over the course of the examination was conducted by three independent examiners. RESULTS: Levovist, administered by continuous infusion, resulted in a significantly longer average period of contrast enhancement (9:43 min (extratumoral), 7:34 min (intratumoral)) than did the same dosage administered as a bolus injection through the main channel (6:01 min (extratumoral), 4:54 min (intratumoral), p = 0.0156 (extratumoral); p = 0.0313 (intratumoral), but contrast intensity was decreased. Bolus injection through the injection valve of the i.v. cannula was associated with decreased duration and intensity of contrast enhancement compared with injection through the main channel. CONCLUSION: Compared with bolus injection, the continuous infusion of Levovist resulted in a significant prolongation of the duration but in a decreased intensity of contrast enhancement. Administration of Levovist through the injection valve does not result in optimal contrast enhancement and is therefore not recommended.

Adult↗
PubMed2000

CT and arteriography in the evaluation of indirect myocardial revascularization with a free-muscle transplant: initial experience.

PURPOSE: To examine patients with advanced cardiovascular disease with radiology after indirect myocardial revascularization with a free-skeletal-muscle transplant and to determine whether the attached vessel remains patent over the middle and long terms. MATERIALS AND METHODS: In 10 patients with advanced, inoperable cardiovascular disease treated with indirect myocardial revascularization with a free-muscle transplant, radiologic follow-up was performed postoperatively and every 6 months. All 10 patients underwent selective arteriography of the anastomosed vessel and contrast material-enhanced helical computed tomography (CT) (transverse sections and reconstructions). RESULTS: All patients showed adequate vascular conditions postoperatively, as did nine of 10 patients after 1 year. In one patient, the anastomosed artery was occluded. CT showed time-dependent muscle degeneration in all patients. Postoperative, contrast-enhanced, superselective CT showed an area of high-attenuating uptake in the muscle transplant in all patients. After 1 year, CT depicted perfusion defects of the skeletal muscle in two patients. In eight patients, however, small vascular bridges from the skeletal muscle to the myocardium were detected. Radiologic results correlated well with clinical outcome and stress electrocardiograms. CONCLUSION: Helical intraarterial CT and arteriography were sensitive in depicting enhancement and remaining vital function in nine of 10 patients after indirect myocardial revascularization with a free-muscle transplant. This combination seems promising for postoperative examination in such patients.

Aged↗
PubMed1999

Improved device definition in interventional magnetic resonance imaging using a rotated stripes keyhole acquisition.

Keyhole acquisition techniques have been used to reduce image acquisition times primarily in contrast agent studies and via simulation in interventional MRI procedures. More recent simulations have suggested that improved definition of an interventional device [e.g., biopsy needles, radio frequency (RF) electrodes] could be achieved by rotating the keyhole pattern in k-space so that the read out direction lies perpendicular to the device orientation in real space. This study seeks to validate the earlier predictions of improved efficacy of a rotated stripes keyhole acquisition in actual in vitro and in vivo interventional MR imaging procedures. A true-FISP sequence was modified to perform central stripes keyhole (as known as conventional keyhole) acquisitions after a full initial reference data set was acquired. The gradients of this sequence were then modified to rotate the k-space definition and the keyhole stripes by 10 degrees, 20 degrees, 30 degrees, 45 degrees, and 60 degrees from their conventional k-space orientation. Acquisitions were performed during insertion of interventional devices in phantom and in vivo RF ablation procedures, using the modified sequence selected which placed the phase encoding axis at parallel and perpendicular orientations to the devices. Resulting images were compared between the two orientations for needle width and tip accuracy. Apparent needle width was thinner and tip position more accurately determined for placement of phase encoding parallel to the needle in all cases. Rotated keyhole imaging provides the required temporal advantage of conventional keyhole imaging along with a near optimal definition of an interventional device when the phase encoding is oriented parallel to the direction of the needle motion. Magn Reson Med 42:554-560, 1999.

Animals↗
PubMed1999

MR mammography: influence of menstrual cycle on the dynamic contrast enhancement of fibrocystic disease.

Magnetic resonance mammography (MRM) provides data regarding the nature of tumours based on contrast medium dynamics; fibrocystic changes in the breast, however, may lead to false-positive results. This study investigated whether the contrast medium dynamics of fibrocystic changes are dependent on the menstrual cycle. Twenty-four patients with palpable lumps but normal mammographies and ultrasound studies were examined. The MRM technique was performed during the first and second part of the menstrual cycle using a FLASH 3D sequence, both native and at 1, 2, 3 and 8 min after intravenous application of 0.15 mmol/kg body weight of gadodiamide. The calculated time-intensity curves were evaluated based on the following criteria: early percentage of contrast medium uptake in relation to the native value; formation of a plateau phenomenon after the second minute; the point of maximal contrast medium uptake; and calculation of the contrast enhancing index. During the second half of the menstrual cycle, a generally greater contrast medium uptake was observed. Nevertheless, when further diagnostic criteria, such as continuous contrast medium increase as a function of time, were considered, there was no increased rate of false-positive findings. The phase of the menstrual cycle may affect the specificity of the examination, if only the quantitative contrast medium uptake and the percentage of contrast medium uptake in the first 2 min are considered. A control MRM during the other half of the cycle may then be indicated and additional diagnostic criteria may improve specificity.

Adult↗
PubMed1999

The role of docetaxel (Taxotere) in neoadjuvant chemotherapy of breast cancer.

Neoadjuvant chemotherapy has become standard therapy in the management of breast cancer patients with locally advanced disease with inoperable tumors and inflammatory breast cancer. Patients with earlier stage breast cancer and operable tumors may also benefit from treatment with neoadjuvant chemotherapy. Docetaxel (Taxotere; Rhône-Poulenc Rorer, Collegeville, PA) is thought to be one of the most potent agents in the treatment of metastatic breast cancer and is therefore being investigated for its likely benefit in preoperative, neoadjuvant regimens. Several large phase II and randomized phase III trials are evaluating docetaxel as a single agent, in combination, and/or sequentially in the preoperative setting. Preliminary findings demonstrate high complete and partial response rates and a tolerable toxicity profile. These results are consistent with the view that incorporation of docetaxel in neoadjuvant chemotherapy regimens will contribute to improved patient outcome. Ongoing studies will provide important information regarding the most appropriate regimens and schedules of docetaxel to use in the preoperative, neoadjuvant setting.

Anthracyclines↗
PubMed1998

MRI follow-up of pisiform bone transposition for treatment of lunatomalacia.

OBJECTIVE: Transposition of the pisiform bone is an operative treatment for lunatomalacia. The postoperative viability of the transposed pisiform bone is difficult to assess. The purpose of the study was to evaluate the utility of MRI for postoperative assessment of viability of the pisiform and lunate bones. DESIGN AND PATIENTS: Six patients who underwent transposition of the pisiform for treatment of lunatomalacia, were assessed pre- and postoperatively with conventional radiographs (including tomography), CT and MRI. RESULTS: Conventional radiographs, conventional tomograms and CT were all useful in demonstrating the location of the transposed pisiform. CT showed the transposed pisiform without superposition. However, neither CT nor conventional techniques provided information regarding viability of the pisiform. In all patients investigated in the first year following surgery, T1-weighted MR images showed high signal intensity in the transposed bones. In all patients investigated after 1 year, the signal intensity decreased to an intermediate level on T1-weighted images. Enhancement following contrast medium administration in the transposed pisiform and the lunate was noted in all patients, indicative of viability. CONCLUSION: Contrast-enhanced MRI is able to provide important information regarding the viability of the transposed pisiform and the remaining parts of the lunate. Thus, contrast-enhanced MRI provides an improved means of postoperative assessment regarding short-term follow-up following pisiform transposition. In the long-term follow-up conventional radiography and CT may be equal to MRI in showing increasing sclerosis and/or fragmentation.

Adolescent↗
PubMed1998

[Value of dynamic MRI in the diagnosis of hypophyseal microadenomas].

PURPOSE: To evaluate dynamic MR imaging of the pituitary gland. MATERIAL AND METHODS: 19 patients with suspected mass lesions of the pituitary gland were examined at 1.5 Tesla with dynamic and standard MRI using a Turbo-FLASH sequence (1 image/s for 40 s). RESULTS: In 13/19 patients microadenomas were detected. One of the 13 microadenomas was detected using dynamic imaging and was not seen on standard MRI. The remaining 12 microadenomas were diagnosed with standard MRI. CONCLUSION: Dynamic imaging of the pituitary gland is a time-consuming and costly diagnostic technique. If laboratory results suggest the presence of a microadenoma and conventional MRI is unable to localise it, dynamic imaging should be performed.

Adenoma↗
PubMed1998

Extranodal malignant lymphoma: detection with FDG PET versus CT.

PURPOSE: To evaluate use of functional imaging with positron emission tomography (PET) versus computed tomography (CT) for detection of extranodal lymphoma spread. MATERIALS AND METHODS: Eighty-one consecutive and previously untreated patients with malignant non-Hodgkin lymphoma (n = 43) or Hodgkin disease (n = 38) were examined with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) PET and contrast material-enhanced CT. Concordant findings at both CT and FDG PET were regarded as actual locations of disease; discordant results were resolved on the basis of biopsy or follow-up results when possible. RESULTS: Forty-two lesions were identified at both PET and CT, and 19 were verified with biopsy results. PET demonstrated a further 24 lesions. Verification was possible in 15 of these lesions with biopsy (n = 10), magnetic resonance imaging (n = 1), scintigraphic (n = 1), or follow-up (n = 3) results. In 14 of these 15 lesions, PET findings were confirmed (bone marrow, nine; spleen, three; other, two). Seven lesions not visualized at FDG PET were identified at CT, six of which were verified with biopsy (n = 2) or follow-up (n = 4) results. Five of these six CT findings were found to be erroneous. In 13 patients, PET findings led to changes in tumor staging. CONCLUSION: PET may provide more information about extranodal lymphoma than does incremental CT.

Adult↗
PubMed1998

The average dose-area product at intravenous urography in 205 adults.

The intravenous urography (IVU) is the most important and most frequently performed radiological examination in urology. This prospective study determined the dose-area product as a measurement of radiation dose in 205 adult patients undergoing IVU. Average dose-area product was 1017 cGy cm2. An average 3.7 radiographs were obtained per patient. Tomographic views were required in only 8.8% of cases. Radiation dose is dependent not only on the number and size of the obtained radiographs, but on the physical constitution of the patient. The dose-area products measured show a clear relationship to the body weight of the patient.

Adolescent↗
PubMed1997

Oral administration of iopentol (Imagopaque 300 mg I/ml) compared with amidotrizoate (Peritrast 300 mg I/ml), both diluted to 2% (v/v), in imaging of the gastrointestinal tract in abdominal contrast enhanced CT. A clinical trial assessing patient tolerance, distribution of contrast medium and Hounsfield unit measurements.

The aim of the trial was to evaluate and compare the safety and efficacy of iopentol (Imagopaque, Nycomed Imaging AS, Oslo, Norway) and amidotrizoate (Peritrast, Köhler Pharma, Alsbach, Germany), both 300 mg I/ml initially, but diluted to 2% (v/v) and administered orally. Sixty-four and 65 patients were included in the respective contrast medium groups. Portions of contrast medium, totally 1.51, were taken every 15 min during the hour before the examination. A standard radiological procedure for abdominal CT was followed. Nine percent of the patients in each group experienced adverse events which were possibly contrast medium related. Taste acceptance was comparable in the two groups. Except for the stomach, radiographic efficacy was satisfactory for all intestinal segments. The difference in density in the proximal small bowel (main parameter) achieved with the media was not significant (p = 0.33), nor was that as regards image homogeneity (contrast distribution). In conclusion, iopentol is well suited for oral contrast enhancement of the gastrointestinal tract in abdominal computed tomography.

Administration, Oral↗
PubMed1997

Tunnel placement in anterior cruciate ligament reconstruction: MRI analysis as an important factor in the radiological report.

OBJECTIVE: Correct placement of tunnels for anterior cruciate ligament (ACL) reconstruction is of prime importance for the clinical outcome of the patient. In this study, the possibility of using MRI to document tunnel placement and provide a more comprehensive report following ACL reconstruction was explored at no additional cost in patients scheduled for routine knee MRI DESIGN AND PATIENTS: One year after ACL reconstruction, 45 patients underwent clinical examination (IKCD score), radiographic examination, and MRI using a 1.5-T unit. RESULTS: Twenty patients with good tibial and femoral attachment results were found at clinical examination to have a stable knee joint with a full range of motion. In 25 patients with suboptimal placements, examination showed either a stable knee with a decreased range of motion or instability with a normal range of motion. CONCLUSION: Patients' clinical outcome, and the radiographic and MRI findings, correlated closely with the quality of operative tunnel placement. A record of this finding is important for completeness of the radiological report. Furthermore the MRI findings can be used to improve the surgical quality of tunnel placement. Because tunnel placement can be shown adequately with radiography, however, MRI cannot be justified for this reason alone, so such assessment is advised only when MRI is needed to show all postoperative features.

Adult↗
PubMed1997

Usefulness of FDG-PET in diagnosing primary lymphoma of the liver.

This case report shows for the first time the usefulness of positron emission tomography (PET) with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) in the diagnosis of primary non Hodgkin's lymphoma of the liver. Results of FDG-PET, which in contrast to other imaging techniques offers the advantage of screening the whole body, demonstrated a high glycolytic activity of a solitary mass in the liver with central necrosis (loss of glycolytic activity), but no spread of lymphoma to the body. These results were confirmed by ultrasound, computed tomography, magnetic resonance imaging and were biopsy proven. From our findings we conclude that in patients with liver masses with high uptake of FDG, lack of liver dysfunction and absence of signs indicating other malignancies, a primary lymphoma of the liver should be considered as a possible diagnosis.

Female↗
PubMed1997

[Mechanically detachable minicoils attached to a wire for superselective embolization].

PURPOSE: Evaluation of clinical usability and effectivity of newly developed, mechanically applicable minicoils attached to a wire for super-selective embolisation. MATERIAL AND METHODS: The new embolisation coils have been used in 16 patients aged between 28 and 90 years for the following indications: 4 haemorrhages in cases of advanced carcinoma of the cervix, one false aneurysm, 7 traumatic lesions and 4 arteriovenous fistulas. The minicoils are made of platinum and are attached to a guide wire with a connecting hook. Application is via a microcatheter in coaxial technique. RESULTS: Percutaneous embolisation has been successful in patients. Additional surgery has not been required in any of them. Manipulation of the system is relatively easy and embolisation is made possible under controlled circumstances. In one case a minicoil disappeared into a peripheral vessel, but could be recovered percutaneously. CONCLUSION: The minicoils allow super-selective embolisation but, for reasons of cost, should be reserved to such vascular regions where the risk of misplacing must be kept at a minimum. Basic experience with embolisation techniques is indispensable for the application of this method.

Adult↗
PubMed1997

[Doubtful mammographic findings: the value of negative MR mammography for tumor exclusion].

PURPOSE: To determine whether the addition of MR mammography (MRM) is useful in excluding malignant lesions and how reliable negative MRM findings are. METHODS: Amongst 694 MRM's, those originally regarded as normal were retrospectively reappraised. 239 female patients were involved. In all these patients there were clinical, sonographic and/or mammographic findings which were not entirely normal but there was no urgent indication for histological clarification. In 46 patients there were, however, histological examinations since the patients themselves insisted on it. In the remaining patients there was clinical, sonographic, mammographic and/or MRM follow-up after 12 to 18 months. RESULTS: In 95.4% (200/239) a carcinoma could be excluded by means of MRM, in 7 patients a carcinoma in situ and in two patients an invasive carcinoma was demonstrated histologically which had not been demonstrated by MRM. Even in retrospect, no abnormality could be found. CONCLUSION: Because of the only moderate sensitivity of MRM in the recognition of carcinoma in situ, doubtful lesions which can be localised, should be biopsied by a stereotactic method. In cases where evaluation is difficult on clinical, sonographic and mammographic findings, MRM is of value in excluding tumours, particularly in patients with increased carcinoma risk.

Adolescent↗
PubMed1997

Lymphoma: role of whole-body 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) PET in nodal staging.

PURPOSE: To compare 2-deoxy-2-[fluorine-18]fluoro-D-glucose (FDG) positron emission tomography (PET) with computed tomography (CT) in primary nodal staging of malignant lymphoma. MATERIALS AND METHODS: Sixty consecutive patients with untreated, histopathologically proved malignant lymphoma (aged 7-72 years; 33 with non-Hodgkin lymphoma, 27 with Hodgkin disease) underwent FDG PET and contrast material-enhanced CT for nodal staging. Lymph node regions identified at both CT and PET were regarded as actual locations of disease. Discordant results were verified with biopsy or clinical follow-up whenever possible. RESULTS: One hundred sixty of 740 evaluated lymph node regions were identified as diseased at both CT and PET. Of the 25 additional regions seen with PET, seven were true-positive; two, false-positive; and 16, unresolved. CT showed six additional disease manifestations; three were false-positive, and three were unresolved. Staging was changed in the four patients with the seven confirmed additional PET findings: from stage I to II in one patient and from stage II to III in three patients. Staging was changed from stage II to I in one of the three patients with false-positive CT findings. CONCLUSION: FDG PET may be more accurate for detecting nodal lymphoma than incremental CT.

Adolescent↗