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Biomedical subjects

D Weishaupt

Publications and source records attributed to D Weishaupt.

At least 55 records · Page 3Linked to original sources
PubMed1999

Sequential fast 3D MRI following oral ingestion of Gd-DOTA: A new means to assess intestinal transit time.

A magnetic resonance image (MRI)-based method to determine the colonic transit time is described. It is based on the oral ingestion of a single dose of 4 ml Gd-DOTA following an overnight fast and the subsequent acquisition of fast three-dimensional (3D) gradient-echo sequences under apnea conditions. The technique was successfully evaluated in three healthy volunteers. Transit of the contrast agent through the small and large intestines was easily followed. Thus, MRI-based colonic transit time determinations are feasible.

Administration, Oral↗
PubMed1999

MR imaging and CT in osteoarthritis of the lumbar facet joints.

OBJECTIVE: To test the agreement between MR imaging and CT in the assessment of osteoarthritis of the lumbar facet joints, and thus to provide data about the need for an additional CT scan in the presence of an MR examination. DESIGN AND PATIENTS: Using a four-point scale, two musculoskeletal radiologists independently graded the severity of osteoarthritis of 308 lumbar facet joints on axial T2-weighted and on sagittal T1- and T2-weighted turbo-spin-echo images and separately on the corresponding axial CT scans. Kappa statistics and percentage agreement were calculated. RESULTS: The weighted kappa coefficients for MR imaging versus CT were 0.61 and 0.49 for readers 1 and 2, respectively. The weighted kappa coefficients for interobserver agreement were 0.41 for MR imaging and 0.60 for CT, respectively. There was agreement within one grade between MR and CT images in 95% of cases for reader 1, and in 97% of cases for reader 2. CONCLUSION: With regard to osteoarthritis of the lumbar facet joints there is moderate to good agreement between MR imaging and CT. When differences of one grade are disregarded agreement is even excellent. Therefore, in the presence of an MR examination CT is not required for the assessment of facet joint degeneration.

Adult↗
PubMed1999

MR imaging of inflammatory joint diseases of the foot and ankle.

Pain affecting the foot and ankle is a common complaint frequently attributable to inflammatory joint diseases. Although conventional radiography is regarded as the initial step in the diagnostic investigation, MR imaging may contribute to further evaluation of these patients due to the direct visualization of the inflammatory soft tissue formed in the disease and its effects on bone, cartilage and para-articular structures. The high spatial resolution of MR imaging combined with tissue characterization often allows initial detection of inflammatory joint abnormalities at a stage that precedes radiographic evaluation. The typical MR appearance of certain inflammatory joint disorders may be helpful in narrowing the wide differential diagnosis. Furthermore, MR imaging can be used for an exact assessment of the extent of the disorder as well as its complications. Accurate diagnostic information can guide the clinician in further diagnostic tests and implementation of proper therapeutic treatment.

Adult↗
PubMed1999

Real-time MR-guided joint puncture and arthrography: preliminary results.

The purpose of this study was to evaluate interactive MR-guided joint puncture with intra-articular application of contrast agent. MR-guided arthrography of the shoulder joint was successfully performed in three patients using an interactive guidance system implemented in an open-configuration MR system. Visualization of the needle pathway and contrast inflow was comparable to that with conventional X-ray fluoroscopy. The position of the intra-articular needle tip was accurately confirmed and subsequent MR arthrography was diagnostic in all cases.

Adult↗
PubMed1999

Lesions of the reflection pulley of the long biceps tendon. MR arthrographic findings.

RATIONALE AND OBJECTIVES: The purpose of this study was to assess the diagnostic value of MR arthrography in detecting a lesion of the common insertion of the coracohumeral and the superior glenohumeral ligaments and the superior border of the subscapularis tendon (pulley lesion), which predisposes to biceps tendon subluxation and subsequent degeneration. METHODS: Parasagittal T1-weighted turbo spin-echo and axial gradient-echo (three-dimensional fast imaging with steady state-precession [FISP]) MR arthrographic images were obtained in 14 patients with surgically confirmed pulley lesions and in 10 patients with an intact pulley. Various MR arthrographic signs potentially associated with a pulley lesion were evaluated separately and independently in a blinded fashion by two radiologists. RESULTS: Abnormalities of the superior border of the subscapularis tendon on axial and parasagittal images, extra-articular contrast collection, and biceps tendon subluxation were the MR findings of a pulley lesion. The coracohumeral and superior glenohumeral ligaments were not readily visible in all patients and were not helpful in diagnosing pulley lesions in this study. The overall sensitivity for detecting a pulley lesion by MR arthrography was 86% and 93% for readers 1 and 2, with a specificity of 100% and 80% and an accuracy of 92% and 87% (kappa = 0.75). CONCLUSIONS: Based on the authors' experience, MR arthrography is valuable in detecting lesions of the reflection pulley of the long biceps tendon, although differentiation from an isolated lesion of the superior border of the subscapularis tendon may not be possible.

Adult↗
PubMed1999

Magnetic resonance: evaluation of adrenal lesions.

Magnetic resonance imaging provides a detailed display of adrenal anatomy. The development of new imaging sequences, especially chemical shift imaging, has vastly enhanced the specificity of magnetic resonance imaging. This review outlines current magnetic resonance imaging strategies for assessing disease affecting the adrenal glands. Particular emphasis is placed on the characterization of adrenal masses.

Adrenal Gland Diseases↗
PubMed1999

Comparison of three dimensional magnetic resonance imaging in conjunction with a blood pool contrast agent and nuclear scintigraphy for the detection of experimentally induced gastrointestinal bleeding.

BACKGROUND AND AIMS: To compare the performance of 3D magnetic resonance imaging (MRI) in conjunction with an intravascular contrast agent with that of scintigraphy, with respect to detection and localisation of gastrointestinal haemorrhage in vivo in pigs. METHODS: Intraluminal bleeding sites were surgically created in the small bowel and colon of six pigs. The animals underwent scintigraphy with (99m)Tc labelled red blood cells and 3D MRI following administration of an intravascular contrast agent (NC100150) at five minute intervals over 30 minutes. For analysis, the intestinal tract was divided into six segments. Based on the two evaluated methods, each segment was characterised on a five point scale regarding the presence of a bleed. At autopsy, the surgically manipulated bowel segments were inspected for the presence of haemorrhage. RESULTS: Bleeding was confirmed at autopsy in 18/36 segments. Contrast extravasation with subsequent movement through the bowel could be documented on MRI data sets. All segments were correctly characterised, resulting in 100% sensitivity and specificity for MRI. Based on scintigraphy, interpretation of seven segments (19%) was false (sensitivity/specificity of 78%/72%). Differences in diagnostic performance were evident in the receiver operator characteristic (ROC) analysis, with an area under the MRI curve of 0.99 and under the scintigraphy curve of 0.85. CONCLUSION: In conjunction with an intravascular contrast agent, 3D MRI permits accurate detection and localisation of gastrointestinal bleeding. The extent and evolution of intestinal bleeding can be determined with repeated data acquisition.

Animals↗
PubMed1999

MR colonography: optimized enema composition.

Manganese chloride, iron glycerophosphate, and cellulose additive were assessed as base materials for use in a T1-shortening single contrast enema for magnetic resonance (MR) colonography. Contrast-to-noise ratios (CNRs) were compared to those with the standard 10 mmol/L gadolinium-based enema. On T1-weighted three-dimensional gradient-recalled-echo images, CNRs with the iron glycerophosphate enema exceeded those with the manganese- and gadolinium-based enemas. Use of an additive of 0.8% wt/wt cellulose was found to be practicable as it increased viscosity sufficiently without altering CNR. The gadolinium-based enema can be replaced with an iron glycerophosphate enema to render MR colonography less costly.

Adult↗
PubMed1999

Subscapularis tendon tears: detection and grading at MR arthrography.

PURPOSE: To assess diagnostic accuracy in the detection and grading of subscapularis tendon lesions at magnetic resonance (MR) arthrography. MATERIALS AND METHODS: MR arthrograms in 50 consecutive patients (29 with normal subscapularis tendons, 11 with a lesion in the cranial quarter, seven with a major tear but not complete detachment, three with complete detachment) with arthroscopic or surgical confirmation were evaluated independently by two radiologists. Diagnosis was established on findings from transverse and/or parasagittal images. RESULTS: With transverse images alone, sensitivity was 95%/100% (reader 1/reader 2); specificity was 55%/62%. With parasagittal images alone, sensitivity was 91%/91%; specificity was 76%/90%. With combined images, sensitivity was 91%/91%; specificity was 86%/79%. Interobserver agreement was substantial (kappa = 0.67). Forty-one of 50 (82%) grades for subscapularis abnormalities matched at MR imaging and surgery; nine mismatches differed by only one degree. Several signs were specific (90%-100%) but insensitive (29%-62%); these included leakage of contrast material onto the lesser tuberosity, fatty degeneration of the subscapularis muscle, and abnormality in the course of the long biceps tendon (luxation, subluxation). CONCLUSION: MR arthrography is accurate in the detection and grading of subscapularis tendon lesions. Specificity of findings on transverse images for this diagnosis can be improved by including indirect signs and findings on parasagittal images.

Adult↗
PubMed1999

MR imaging for traumatic tears of the rotator cuff: high prevalence of greater tuberosity fractures and subscapularis tendon tears.

OBJECTIVE: The purpose of this study was to determine whether occult bony injuries or other characteristic MR abnormalities are frequent in patients suspected of having traumatic tears of the rotator cuff. SUBJECTS AND METHODS: MR arthrography of the shoulder was performed in 24 consecutive patients with suspected traumatic tears of the rotator cuff. MR findings were analyzed with regard to abnormalities of the supraspinatus, infraspinatus, and subscapularis tendons; and the humeral head. A comparison group of 24 consecutive patients with symptoms of nontraumatic tears of the rotator cuff was included in the investigation. RESULTS: Radiographically occult fractures of the greater tuberosity were found in nine (38%) of 24 patients with clinically suspected traumatic tears of the rotator cuff (seven of which occurred in patients <40 years old). Nine partial-thickness and five full-thickness supraspinatus tears were found in the trauma group. In the comparison group, the corresponding numbers were 13 and 10, respectively. Seven partial lesions of the cranial border of the subscapularis and six complete subscapularis tears (all six in patients >40 years old) were found in the trauma group (nine and one in the comparison group). CONCLUSION: Occult greater tuberosity fractures and complete subscapularis tears are commonly seen on MR images in patients suspected of having traumatic tears of the rotator cuff. Greater tuberosity fractures should be looked for specifically in patients younger than 40 years, and subscapularis tears should be looked for specifically in patients older than 40 years.

Adult↗
PubMed1998

Therapeutic embolization of a systemic arterialization of lung without sequestration.

We report the case of a 51-year-old man with massive haemoptysis due to a systemic arterialization of lung without sequestration. Unlike bronchopulmonary sequestration there was a normal bronchial distribution and the involved lung parenchyma was normal. Therefore a therapeutic transarterial embolization of the aberrant systemic vessel from the distal thoracic aorta was performed. The embolization was successful and the patient did not suffer from further haemoptysis during the subsequent follow-up of ten months. A postembolization aortogram 6 months later demonstrated a complete occlusion of the embolized aberrant artery; in the lung perfusion scan there was only a small perfusion defect, but normal ventilation in the embolized basal part of the left lower lobe. Our case represents an alternative treatment to surgery for this rare anomaly.

Angiography↗
PubMed1998

MR imaging of the lumbar spine: prevalence of intervertebral disk extrusion and sequestration, nerve root compression, end plate abnormalities, and osteoarthritis of the facet joints in asymptomatic volunteers.

PURPOSE: To identify the magnetic resonance (MR) abnormalities of the lumbar spine that have a low prevalence in asymptomatic patients and thus determine the findings that are predictive of low back pain in symptomatic patients. MATERIALS AND METHODS: Sagittal T1-weighted and sagittal and axial T2-weighted MR images were obtained in 60 asymptomatic volunteers aged 20-50 years. The MR images were evaluated with regard to intervertebral disk abnormalities, end plate abnormalities, and osteoarthritis of the facet joints by two musculoskeletal radiologists independently. RESULTS: Disk bulging or disk protrusion was found in 42 (14%) and 48 (16%) of the intervertebral spaces in 37 (62%) and 40 (67%) subjects, respectively. High-signal-intensity zones were found commonly (in 23 [7.7%] and 25 [8.3%] of the intervertebral spaces in 19 (32%) and 20 (33%) subjects, respectively). Disk extrusions were less common (in 11 [3.7%] and 11 [3.7%] of the intervertebral spaces in 11 (18%) and 11 (18%) subjects, respectively). There were no disk sequestrations. A nerve root compression in a single intervertebral space was diagnosed by one reader. End plate abnormalities were found in two (0.7%) and six (1.9%) of the intervertebral spaces in two (3%) and six (10%) subjects, respectively. No severe osteoarthritis was diagnosed by either reader. CONCLUSION: In patients younger than 50 years, disk extrusion and sequestration, nerve root compression, end plate abnormalities, and osteoarthritis of the facet joints are rare and, therefore, may be predictive of low back pain in symptomatic patients.

Adult↗
PubMed1998

Tendinopathy and rupture of the tendon of the long head of the biceps brachii muscle: evaluation with MR arthrography.

OBJECTIVE: The purpose of this study was to assess the diagnostic role of MR arthrography in patients with tendinopathy or rupture of the long biceps tendon. MATERIALS AND METHODS: MR arthrograms of 42 consecutive patients with arthroscopic or surgical confirmation of diagnosis (16 normal biceps tendons, 19 with tendinopathy, and seven with ruptures) were analyzed independently by two radiologists. Visibility of the biceps tendon, caliber changes, contour irregularities, and signal intensities were assessed separately in the parasagittal and axial planes. In addition, the two radiologists made an overall evaluation of abnormalities of the biceps tendon using both MR imaging planes. RESULTS: The most reliable MR findings for tendinopathy were caliber changes (sensitivity was 59% for observer 1 and 82% for observer 2; specificity was 88% and 64%, respectively) and signal abnormalities (sensitivity, 77% and 88%, respectively; specificity, 75% and 43%, respectively) in the parasagittal plane. Absence of visualization of the tendon in the parasagittal plane was a reliable sign for rupture (sensitivity, 86% and 86%, respectively; specificity, 94% and 87%, respectively). The overall sensitivity for detecting abnormalities (tendinopathy or rupture) was 92% for observer 1 and 89% for observer 2. Specificity was 56% and 81%, respectively. CONCLUSION: MR findings of tendinopathy and rupture of the biceps tendon are subtle. However, the combination of several MR criteria in two imaging planes makes a reasonably accurate diagnosis possible. The biceps tendon should not only be assessed in the bicipital sulcus on axial images but also on parasagittal images.

Adult↗
PubMed1997

[Ultrasound findings after shoulder dislocation].

AIM: Sonography of the shoulder is an effective method for detecting tears of the rotator cuff and bone lesions. The purpose of this study was to evaluate prospectively the sonographic findings after shoulder dislocation. METHODS: Sonography was performed on 208 patients with 210 shoulder dislocations, which were all verified by radiography. RESULTS: We diagnosed 62 rotator cuff lesions (29.5%), which were all in the group with traumatic shoulder dislocation. The incidence of tears in patients with first traumatic dislocation (n = 134) was 36.5%. 12 tears (21.8%) of the rotator cuff were noted in recurrent dislocations (n = 55). 23 fractures or bony avulsions of the greater tuberosity of the humerus (11%) and 168 Hill-Sachs lesions (80%) were seen. CONCLUSION: Sonographic examination of the shoulder revealed a significant amount of information that would remain undetected without the aid of expensive and/or invasive diagnostic tools.

Adolescent↗
PubMedDate not supplied

Primary neuroendocrine tumors of the liver: MRI features in two cases.

We report on two patients who underwent magnetic resonance imaging (MRI) as part of the evaluation of focal liver lesions. Both lesions had completely different MRI appearances, showing characteristics of benign and malignant liver lesions. Neither patient had clinical signs of endocrine hyperactivity, and both underwent subsequent liver resection. Histology showed neuroendocrine liver tumors in both patients; and because no primary tumor could be identified after careful search, the diagnosis of primary neureoendocrine tumor of the liver was established. Our observations suggest that primary neuroendocrine tumors of the liver may have a wide spectrum of appearances on MRI.

Female↗
PubMedDate not supplied

Pulmonary hemorrhage: imaging with a new magnetic resonance blood pool agent in conjunction with breathheld three-dimensional magnetic resonance angiography.

PURPOSE: To describe the three-dimensional magnetic resonance angiography (3D MRA) imaging appearance of the pulmonary arteries following administration of a superparamagnetic iron oxide blood pool agent to human volunteers, and to demonstrate in an animal model (pigs) how this technique can be used to detect pulmonary parenchymal hemorrhage. METHODS: Two volunteers were examined following the intravenous administration of a superparamagnetic iron oxide blood pool agent (NC100150 Injection, Nycomed Amersham Imaging, Wayne, PA, USA). T1-weighted 3D gradient recalled echo (GRE) image sets (TR/TE 5.1/1.4 msec, flip angle 30 degrees ) were acquired breath-held over 24 sec. To assess the detectability of pulmonary bleeding with intravascular MR contrast, pulmonary parenchymal injuries were created in two animals under general anesthesia, and fast T1-weighted 3D GRE image sets collected before and after the injury. RESULTS: Administration of the intravascular contrast in the two volunteers resulted in selective enhancement of the pulmonary vasculature permitting complete visualization and excellent delineation of central, segmental, and subsegmental arteries. Following iatrogenic injury in the two animals, pulmonary hemorrhage was readily detected on the 3D image sets. CONCLUSION: The data presented illustrate that ultrafast 3D GRE MR imaging in conjunction with an intravenously administered intravascular blood pool agent can be used to perform high-quality pulmonary MRA as well as to detect pulmonary hemorrhage.

Adult↗