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Biomedical subjects

G H Mostbeck

Publications and source records attributed to G H Mostbeck.

At least 19 recordsLinked to original sources
PubMed1999

Randomized in vitro and in vivo evaluation of different biopsy needles and devices for breast biopsy.

In an experimental study (in vitro and in vivo) we evaluated the efficacy of various biopsy needles/devices for breast biopsy. In vitro, biopsies of five human cadaveric breast specimens were performed using 33 different needles/devices ranging from 14 to 20-gauge. Of these 33 needles/devices, 22 optimally performing needles were selected for the in vivo study. In the clinical part of the study, 44 breast lesions were randomly biopsied with each of the 22 needles/devices under stereotactic guidance. Tissue specimens were analysed quantitatively and qualitatively. Several automatic long-throw guns (Acecut, Asap, Biopty, Magnum) obtained greater tissue areas and had a better histopathologic score than the conventional type of a side-notch needle like Trucut, an aspiration needle like Surecut, or an end-cut needle like Autovac. The automatic long-throw guns performed better than the short-throw Monopty gun. Regardless of needle size (14-20-gauge), breast biopsies should be routinely performed with automated long-throw side-notch guns (Acecut, Asap, Biopty, Magnum).

Adult↗
PubMed1999

The postoperative spine.

During the last decade, magnetic resonance imaging (MRI) mostly has replaced computed tomography for evaluation of spinal surgery patients. The inherent advantages of MRI are obvious for this particularly difficult field of imaging. With MRI, it is possible to demonstrate anatomic as well as pathological and iatrogenic changes in three different imaging planes and countless neighboring planes and to obtain a superior view of the complex postoperative situation regardless of the spinal level imaged. Soft-tissue masses in particular can be identified more readily and located within three-dimensional space. One of the major advantages is that the nature and histology of the mass can be estimated precisely using different MR sequences in combination with intravenous contrast media. The most important benefit may be demonstration of inflammatory and hemorrhagic masses in the early postoperative periods (with special emphasis on alterations visible in the spinal cord itself) as well as repair processes and ongoing degeneration in later stages. This visualization is possible even when their extent is limited. In the postoperative spine, the application of MRI was facilitated with the advent of new materials, such as titanium alloys, used for surgical instrumentation. These new materials limit the amount of artifacts visible on MR images. Earlier implants made of other metallic material prohibit the use of computed tomography in the spine. This article provides a brief overview of the progress in spinal surgery and focuses on the developments in MRI techniques during the last decade. Technical questions about imaging of spinal instrumentation are discussed. "Normal" postoperative findings needed for interpretation of pathologic conditions are also discussed. Finally, the most important frequently asked questions from referring surgeons that radiologists must be able to answer by MRI are presented.

Alloys↗
PubMed1998

[Ewing sarcoma. Diagnostic imaging].

Ewing's sarcoma is a highly malignant neoplasm of the bone whose origin is still uncertain. A strong relationship exists between Ewing's sarcoma and tumors of neural origin (Ewing family of tumors). Ewing's sarcoma must be distinguished from other round-cell tumors like lymphoma and neuroblastoma and also must be differentiated from osteogenic sarcomas. On plain radiographs, Ewing's sarcoma appears as a lytic or mixed lytic-sclerotic, rarely as predominantly sclerotic lesion with margins Lodwick grade III. It is located primarily in the diaphyseal and metadiaphyseal regions of the long bones of the lower extremities. A large soft tissue tumor is usually present. Magnetic resonance imaging is the imaging modality of choice to evaluate the extent of the primary lesion, to monitor the response to neoadjuvant chemotherapy and to follow up non-resected Ewing's sarcomas. Bone scintigraphy is necessary to detect skeletal metastasis, and 201thallium scanning has been shown to be sensitive in the monitoring of treatment response. Today, computed tomography is not longer used to image the tumor site; however, spiral CT of the lungs plays a central role as a staging and follow-up tool.

Bone Neoplasms↗
PubMed1998

Central nervous system disease in Langerhans cell histiocytosis.

Central nervous system (CNS) disease in Langerhans cell histiocytosis (LCH) is a poorly understood complication of yet unknown frequency. By far the most common manifestation is in the hypothalamic-pituitary system with diabetes insipidus as the leading sign, followed by other endocrinopathies and hypothalamic dysfunction. However, essentially all other parts of the CNS may be involved. On the one hand, space-occupying histiocytic infiltrates may lead to size- and site-depending symptoms, extending from adjacent bone lesions or arising from the meninges or choroid plexus. On the other hand, a progressive neurological deterioration can occur with mainly cerebellar-pontine symptoms. In this article, these clinical patterns are described in correlation with the morphology on MR imaging and histopathology. Further, the therapeutic strategies are reviewed critically, and guidelines for the management of patients with LCH-related CNS disease are presented.

Central Nervous System↗
PubMed1998

Pulmonary and aortic blood flow measurements in normal subjects and patients after single lung transplantation at 0.5 T using velocity encoded cine MRI.

PURPOSE: It is the purpose of this study to compare pulmonary and aortic blood flow measurements obtained in patients after single lung transplantation (SLTX) with those in volunteers. METHODS/MATERIAL: In nine patients after SLTX (three male, six female) and nine volunteers (seven male, two female), double oblique phase contrast cine-MRI sequences perpendicular to the direction of blood flow were obtained in the ascending aorta, main, right, and left pulmonary artery on a 0.5-T unit (Philips Gyroscan; Best, the Netherlands) (repetition time, 600 to 800 ms; echo time, 8 ms; alpha=30; field of view=280 mm matrix, 128x256, ECG gating, temporal resolution 16 time frames/RR interval). An initial in vitro study using the same sequence on a nonpulsatile flow phantom showed excellent correlation (r=0.99) between MRI measurements of flow velocity and flow volume and true velocity and flow volume. Measurements of blood flow volume (mL/min), peak mean systolic velocity, resistive index, and distensibility index were obtained in each vessel. RESULTS: We found excellent correlations between left and right cardiac output as measured by velocity encoded cine-MRI (VEC-MRI) in the ascending aorta and main pulmonary artery both in normal volunteers (r=0.95) and in patients (r=0.91). Differential pulmonary blood flow measurements in volunteers showed that 55% of the right cardiac output was directed to the right and 45% to the left lung. Differential pulmonary blood flow in patients showed that most of the blood flow (81%) reaches the transplanted lung and only 19% reaches the patient's own lung (SLTX: 4.5+/-1.8 L/min, patient's own lung: 1.2+/-0.8 L/min). There were significant differences (p<0.05) in peak mean systolic velocity and resistive index obtained in the pulmonary arteries, both between normal volunteers and patients and between measurements obtained in the patient's own lung and the transplanted lung. CONCLUSION: VEC-MRI blood flow measurements are a promising noninvasive tool to monitor the hemodynamic changes of pulmonary blood flow after SLTX.

Adult↗
PubMed1998

Evaluation of needle size for breast biopsy: comparison of 14-, 16-, and 18-gauge biopsy needles.

OBJECTIVE: The purpose of our study was to compare the quantity and quality of tissue harvested from breast biopsy when using 14-, 16-, and 18-gauge "long-throw" needles. SUBJECTS AND METHODS: We performed a prospective randomized study in 64 patients with 66 breast lesions. Under stereotactic guidance, passes were made in random order with each of the three biopsy needles in each lesion. Samples were measured for tissue area and scored for their quality. All lesions, including benign and malignant lesions and lesions with and without microcalcifications, were analyzed. Findings of the biopsy samples were compared with the final diagnoses made at surgical excision. RESULTS: In all 66 lesions, 14-gauge biopsy needles obtained significantly larger specimens (14-gauge, 13.14 mm2; 16-gauge, 9.6 mm2; 18-gauge, 6.41 mm2; p < .05) and scored significantly better (14-gauge, 8.37; 16-gauge, 7.56; 18-gauge, 7.14; p < .016) than either of the smaller needles. The results for malignant and benign lesions and for lesions with and without microcalcifications were similar but not equal to the overall results. However, benign lesions and areas with microcalcifications seem to be more problematic for both smaller needles than for 14-gauge needles. CONCLUSION: Our results indicate that the quantity and quality of breast biopsy specimens depend on the needle size. Of the three needle sizes tested, only 14-gauge long-throw biopsy needles can be recommended for breast biopsy.

Biopsy, Needle↗
PubMed1997

[Pulmonary hypertension and cor pulmonale].

Pulmonary hypertension is a severe disorder of the pulmonary circulation and occurs in a variety of vascular and parenchymal lung diseases. It leads to volume and/or pressure overload of the right ventricle and finally to right heart failure. Pulmonary vascular diseases such as chronic pulmonary embolism cause a drastic increase in pulmonary vascular resistance, which results in extremely high pulmonary artery pressures that can even reach systemic levels. On the other hand, moderate pulmonary hypertension can also occur in chronic obstructive and restrictive lung diseases. For a long time, the diagnosis of pulmonary hypertension and cor pulmonale was based upon findings in echocardiography and right heart catheterization. Today modern imaging techniques allow the radiologist to assess right ventricular and pulmonary artery morphology and function. The application of spiral CT, electron-beam CT and MRT permits the diagnosis and differential diagnosis of pulmonary hypertension and also the evaluation and follow-up of underlying vascular or parenchymal lung disorders. In addition, quantification of right ventricular function and calculation of pulmonary hemodynamic parameters are possible.

Adult↗
PubMed1997

[Sitting or supine stereotaxic core biopsy of the breast? A comparison based on a randomized, prospective study].

UNLABELLED: OBJECTIVE/MATERIAL AND METHODS: In a prospective randomized study, the techniques of stereotactic breast biopsies in prone and sitting position were compared. Part of the data has already been published. A total of 103 women underwent stereotactic breast biopsies, either prone (n = 51; using TRC-Mammotest, Sweden) or in the sitting position (n = 52; using Stereotix 2, General Electric Medical Systems, Milwaukee, Wisconsin, USA). With the help of pre- and post-biopsy questionnaires, anxiety, pain, and subjective experience were recorded in all patients. Vasovagal reactions were scored from 0 to 2 according to their severity. All biopsy results were verified by surgery. The specificities and sensitivities for the two positions were calculated and statistically compared. RESULTS: With regard to overall tolerance no statistically significant difference between biopsies performed in the sitting or the prone position was noted. Significantly more patients (p = 0.04) in the prone position stated they would prefer premedication prior to a repeat biopsy. Three patients (prone; n = 1; sitting; n = 2) fainted during the procedure. There was no statistically significant difference between the two biopsy positions regarding sensitivity (95%) and specificity (100%). CONCLUSIONS: More attention should be paid to patient care and, especially, preintervention information. Biopsies in the prone or sitting position are equally well tolerated. Somatic reactions are not a major problem during breast biopsy. Success and validity are independent of the biopsy position.

Adult↗
PubMed1997

Sonomorphology of the gallbladder in critically ill patients. Value of a scoring system and follow-up examinations.

PURPOSE: The aim of the study was to assess the value of a scoring system for the diagnosis of acalculous cholecystitis (AC) on ultrasound (US) follow-up examinations and to discuss the merits of scoring system compared to clinical outcome and pathohistologic findings. MATERIAL AND METHODS: In this prospective study, 21 patients at the intensive care unit (ICU) of a medical department were examined by follow-up US. Sonographic parameters of the gallbladder (GB) were obtained (longitudinal and transversal diameter, wall thickening, contents, and pericholecystic fluid) and scored (2 points: distension of GB, thickening of GB wall; 1 point: striated thickening of GB wall, sludge, and pericholecystic fluid; range (0-8). The US findings were correlated with clinical findings and histology at cholecystectomy or autopsy. RESULTS: Of a total of 77 follow-up examinations in these 21 patients, US demonstrated GB distension in 19 patients, wall thickening in 18, sludge in 15, striated thickening of the GB wall in 13, and pericholecystic fluid in 12 patients. Of these, 41 (53%) examinations were scored > or = 6, and 36 (47%) examinations < or = 5. None of the patients with a maximum score during follow-up of < or = 5 (n = 8) had pathohistologic proof of AC or died due to GB complications. Patients with maximum scores of > or = 6: had pathohistologic proof of AC (n = 4); survived with normalization of GB morphology (n = 4); had a normal GB at autopsy (n = 1); or were lost for pathohistologic proof at autopsy (n = 2). CONCLUSION: Our results indicate that regular, short-term follow-up allows early diagnosis and immediate therapy for AC. The scoring system could be helpful in differentiating between patients with an abnormal GB without AC (score < or = 5) and those with an abnormal GB (score > or = 6) with a suspicion of AC. In the latter group, more aggressive diagnostic and therapeutic procedures may be indicated.

Adolescent↗
PubMed1997

Differentiation of benign and malignant breast lesions: MR imaging versus Tc-99m sestamibi scintimammography.

PURPOSE: To compare the accuracies of magnetic resonance (MR) imaging and scintimammography in differentiating benign from malignant breast lesions. MATERIALS AND METHODS: MR imaging was performed in 66 women with 75 lesions during intravenous administration of gadopentetate dimeglumine. Planar and single photon emission computed tomographic (SPECT) scintimammography were performed (with 740 MBq technetium-99m sestamibi administered intravenously) in all 66 patients with 75 lesions and in 64 patients with 73 lesions, respectively. MR imaging and scintimammographic studies were independently evaluated by using signal intensity measurements versus time or focal tracer uptake to differentiate benign from malignant lesions. Histopathologic proof was obtained in 63 lesions. Twelve lesions were monitored with follow-up. RESULTS: MR imaging was false-negative in one and false-positive in nine lesions. Planar scintimammography was false-negative in 10 and false-positive in six lesions. SPECT scintimammography was false-negative in four and false-positive in 10 lesions. Sensitivities and specificities for malignancy were, respectively, 96% and 82% for MR imaging, 62% and 88% for planar scintimammography, and 83% and 80% for SPECT scintimammography. CONCLUSION: Both MR imaging and scintimammography are useful in the evaluation of breast cancer. MR imaging is more sensitive and as specific as scintimammography.

Adult↗
PubMed1997

Coaxial technique: approach to breast core biopsies.

PURPOSE: To assess the feasibility of the coaxial core breast biopsy technique performed under stereotactic and ultrasound (US) guidance in vitro and in vivo. MATERIALS AND METHODS: Biopsies were performed in vitro and in vivo with a coaxial technique. In vitro, the true needle-tip deviation was measured with a breast phantom on a stereotactic device with alteration of x and y axes. In vitro US studies were performed to evaluate the optimal technique for harvesting sufficient material for histologic work-up. In 205 patients, coaxial biopsy was performed in 210 suspicious lesions under US (61 lesions) or stereotactic (patient in the sitting position, n = 67; patient in the prone position, n = 82) guidance. In addition, the coaxial system was used for preoperative localization. Surgery and histologic work-up were performed in all cases. RESULTS: In vitro, the true needle-tip deviation was found to be less than indicated on the stereotactic device. A factor was introduced to correct this error. For US guidance, angulation or rotation of the coaxial needle within the lesion proved to be the best technique to increase the size of histologic specimen. Of the 210 lesions, 112 were benign and 98 were malignant. Agreement between biopsy results and final postsurgical histologic analysis was found in 205 cases (98%). CONCLUSION: The coaxial breast biopsy technique is an accurate, simple, and time-saving method performed under stereotactic or US guidance.

Adult↗
PubMed1996

[Calcium in the lung or: it might not always be tuberculosis].

Pulmonary calcifications are a frequent finding in CT examinations of the chest. In many cases, characteristic CT morphology and distribution of pulmonary and mediastinal calcifications may lead to a straightforward specific diagnosis of the underlying disease. In that respect, calcifications are often the residual finding of previous infections. Less often, they may be due to neoplasms, metabolic disorders, occupational exposure or previous therapy. This review focuses on the etiology, pathogenesis and morphological CT features of pulmonary calcifications. A knowledge of the technical aspects of CT imaging is required to verify calcifications and avoid pitfalls.

Calcinosis↗
PubMed1996

[Ultrasound "screening examination" of the abdomen: of value or senseless?].

Screening examinations are diagnostic procedures without an individual indication with the purpose to detect a possible disease in an early, asymptomatic stage. Primary sonographic screening of the abdomen in individuals without any signs or symptoms of abdominal disease cannot be recommended. Secondary screening (sonographic examinations of the total abdomen in patients with unspecific symptoms) and to examine the remaining abdominal, pelvic and retroperitoneal organs which are not needed to answer the specific diagnostic question are procedures of doubtful benefit. However, ultrasound is recommended for specific screening programs, i.e. tumour detection or diagnosis of aneurysms, in those subpopulations with a high prevalence for the specific disease.

Abdomen↗
PubMed1996

[Evaluation system in assessing radiological examinations of clinical significance for the patient].

PURPOSE: The purpose of this study was to test a scoring system and its utility for the assessment of the clinical significance of radiological examinations. MATERIAL AND METHODS: The reports of all diagnostic studies obtained in patients with a clinical suspicion of pancreatitis, urinary tract obstruction, biliary or gallbladder diseases, ileus and gastrointestinal perforation were scored prospectively in 4 categories from 0 to 3. These categories were related to the ability to establish a definite diagnosis, to exclude suspected disease, to influence further diagnostic work-up and therapeutic decision-making. RESULTS: This scoring system showed significant differences of the efficacy of different imaging modalities in these 5 clinical settings. CONCLUSION: This scoring system was helpful to determine the clinical significance of radiological examinations.

Adult↗
PubMed1996

Three-dimensional spiral CT cholangiography in patients with suspected obstructive biliary disease: comparison with endoscopic retrograde cholangiography.

PURPOSE: To evaluate the diagnostic potential of spiral computed tomography (CT) performed after the administration of cholangiographic contrast material (spiral CT cholangiography) in patients with suspected obstructive biliary disease. MATERIALS AND METHODS: After infusion of meglumine iodoxamate, 29 patients underwent upper abdominal spiral CT with subsequent three-dimensional rendering of the biliary tract. In 27 patients, the presence, site, and extent of biliary obstruction were compared with that at endoscopic retrograde cholangiography (ERC). RESULTS: Spiral CT cholangiography correctly depicted biliary obstruction in 14 of 27 patients, with no false-positive or false-negative cases. In one patient, the precise length of a common bile duct stenosis could not be assessed with spiral CT cholangiography. ERC demonstrated intrahepatic ductal stenoses more clearly in two patients. In two patients with hilar cholangiocarcinomas, spiral CT cholangiography depicted undrained areas not seen with ERC. CONCLUSION: Spiral CT cholangiography allows accurate assessment of the biliary system in patients with suspected obstructive biliary disease.

Adult↗