Biomedical subjects

K F Kreitner

Publications and source records attributed to K F Kreitner.

At least 73 records · Page 4Linked to original sources

PubMed1998

[Low-field MR arthrography of the shoulder: early results using an open 0.2T MR system].

PURPOSE: To assess the practicability and image quality of doing MR arthrography of the shoulder using a 0.2T system. PATIENTS AND METHOD: 60 patients (24 with chronic instability, 36 with impingement syndrome) were examined in an open 0.2T MR apparatus (Magnetom Open, Siemens). After the intra-articular injections of 15-20 ml of a 2 mmol Gd-DTPA solution, coronary STIR, T1-weighted, sagittal and axial T2*-weighted FLASH 2D sequences were performed. 21 patients subsequently underwent surgery. RESULTS: Image quality of the T1- and T2*-weighted FLASH 2D sequences was regarded as good or adequate and movement artifacts were minor or moderate. STIR sequences were statistically significantly worse in respect of image quality and movement artifacts (p < 0.001, p < 0.005). The sensitivity and specificity in the diagnosis of rotator cuff rupture as confirmed by surgery was 100% (labrum lesions 100%, 93%). Agreement in the diagnosis of rupture of the supraspinatus and infraspinatus tendons was 0.93 and 0.65. CONCLUSION: MR arthrography of the shoulder using an open 0.2 T MR system provides adequate information concerning the intra articular structures of the joint. The disadvantage is the prolonged duration of the examination with the risk of poor image quality resulting from movement artifacts.

Adult↗

PubMed1998

[Flow quantification of intracardiac shunt volumes using MR phase contrast technique in the breath holding phase].

PURPOSE: Comparison of a breath-hold, velocity-encoded, phase-difference magnetic resonance (MR) sequence for intracardiac shunt flow measurement with the invasive shunt size determination by oximetry. PATIENTS AND METHODS: 10 patients with different cardiac shunts (6 ASD/3 VSD/1 PDA) and four healthy individuals were investigated using a 1.5 Tesla Siemens Vision system. For flow measurements a breath-hold, velocity-encoded, phase-difference magnetic resonance (MR) sequence was used ('through plane', FLASH 2D-sequence, TR/TE 110/5 ms, 'velocity encoding' 250 cm/s). Mean flow (ml/R-R interval) in the ascending aorta, the pulmonary trunk, and the right and left pulmonary arteries was determined. The ratio of the mean flow in the pulmonary circulation (Qp: sum of the mean flows in the right and left pulmonary arteries) and the systemic circulation (Qs: mean flow in the proximal aorta) was compared with the Qp/Qs ratios determined by the invasive oxymetric technique. Oximetry was performed within 24 hours after MR imaging. RESULTS: In the 4 healthy individuals MR flow measurement yielded a Qp/Qs ratio of 0.96 +/- 0.15. In the 10 patients with the various shunt defects, the non-invasive shunt determination by MR gave a Qp/Qs ratio of 2.09 +/- 0.67. The percentage of the calculated shunt sizes was 47.05 +/- 17.45%. In the comparison with the results determined by the invasive oxymetric technique, the MR data showed a strong correlation of r = 0.87. CONCLUSIONS: Breath-hold, velocity-encoded, phase-difference MR-technique enables a reliable quantification of cardiac shunts within a short acquisition time.

Adult↗

PubMed1998

[Stress fractures of the femoral neck due to step aerobics--case report].

With the rising public interest in physical fitness an increasing number of stress reactions of the bone are diagnosed. Commonly known in competitive athletes, they are increasingly seen in recreational sports. Stress reactions of the bone are a disorder between the loading force and the capability to compensate. Stress fractures with displacement of the bone are more rarely diagnosed due to improved diagnostic means. Stress fractures of the medial femoral neck in young athletes are uncommon. We are reporting the case of a beginning tension type stress fracture of the medial femoral neck of a 29 year old female recreational athlete after excessive stepping and step aerobic at a fitness center.

Adult↗

PubMed1998

Superior labrum and labral-bicipital complex: MR imaging with pathologic-anatomic and histologic correlation.

OBJECTIVE: The purpose of this study was to analyze the anatomic relationship between the superior labrum, the superior glenoid rim, the superior glenohumeral ligament, and the long head of the biceps tendon. MATERIALS AND METHODS: Seventeen cadaveric shoulder specimens underwent axial, oblique coronal, and oblique sagittal MR imaging on a 1.5-T imager. Unenhanced proton density- and T2-weighted spin-echo images with and without fat suppression, and T1-weighted fat-suppressed spin-echo images after intraarticular injection of gadolinium, were obtained of each specimen. The shoulders were then frozen and sectioned into 4-mm-thick slices, either transversely or oblique coronally. After gross anatomic correlation, histologic analysis was performed on 32 sections. RESULTS: A sublabral recess was present in 12 (71%) of 17 shoulders. MR arthrography was significantly better at showing the sublabral recess than was unenhanced MR imaging. Histologically, the synovial recess in all cases was covered by synovial lining cells. Intralabral altered histologic patterns were found in 20 (63%) of 32 labral sections. In addition to signs of degeneration, five sections of two specimens showed proliferating fibroblasts and vessels, as well as fibrosis, suggesting trauma. The presence or absence of altered intralabral histologic patterns was better assessed with T1-weighted fat-suppressed arthrograms than with unenhanced MR images. We found a close association grossly and histologically between the superior labrum and the biceps tendon. CONCLUSION: The attachment of the superior glenoid labrum to the glenoid rim shows great variability. In MR imaging, an overlap appears to exist between physiologic recesses of the superior labrum and a type 2 superior labrum anterior-posterior lesion. T1-weighted fat-suppressed MR arthrograms provided the best view of the superior labrum and the labral-bicipital complex.

Aged↗

PubMed1998

[Persistent pulmonary opacification as a sequela of portopulmonary shunt in portal vein thrombosis].

Portopulmonary venous anastomosis are a very rare complication of chronic liver diseases. We report on a patient with a cryptogenic liver cirrhosis and thrombosis of the portal vein who underwent antibiotic treatment because of recurrent pneumonias several times. Although treated successfully a pulmonal infiltrate persisted in further radiologic controls. By means of a velocity-encoded MRI a portopulmonary shunt of 30% of the cardiac output was assured. An operative correction with a distal splenorenal shunt was performed successfully. Former reports of portopulmonary anastomoses complicating chronic liver disease never were hemodynamically relevant. In the presented case, a portopulmonary anastomosis lead to recurrent pneumonias and a restrictive ventilatory disorder.

Female↗

PubMed1997

[Magnetic resonance tomography examination of thoracolumbar spinal fractures after fixateur interne stabilization].

To analyse the possible injuries of vertebral segments, especially the disc, after unstable thoracolumbar fractures stabilised with AO internal fixator, we performed magnetic resonance imaging (MRI) of the traumatised region after implant removal. There were two aspects of disc degeneration (DD):(1) biochemical changes and (2) structural damage. MRI detects biochemical processes as one aspect of DD that is often small even in the presence of greater structural damage of the nucleus pulposus caused by fracture. None of the patients presented with structural failure of the anulus fibrosus, which is the essential structural component of the vertebral segments with regard to stability. We observed biochemical changes more often in the lower of the two fracture-adjacent discs and alterations of discal shape more often in the upper of the two, whereas loss of height concerned both discs to approximately the same degree. The supporters of upper-disc resection in thoracolumbar fractures justify their procedure among other things with the structural disc damage, such as alteration of shape and loss of height (altogether more frequent in the upper disc). Our observations that a disc with a structurally altered nucleus pulposus can be biochemically intact and can show an intact anulus fibrosus are arguments in favour of disc preservation. With regard to the upper disc, the widespread opinion that complete and regular disc damage requires a resection has to be revised. The question of whether the lower disc should be resected more often because of its greater biochemical changes cannot be answered by the present study alone. Besides the excellent static information in all anatomical structures of the vertebral column available by MRI, a repeat examination in a prone position yields dynamic information on the spinal cord in the case of suspected dorsal adhesions.

Adolescent↗

PubMed1997

Hamartoma of the triceps surae muscle.

A 9-year-old, otherwise healthy girl presented with a 5-year history of pain in her right calf with retarded growth and development of an equinus contracture of her right leg. Magnetic resonance imaging showed an irregular mass with heterogeneous enhancement after contrast in her right triceps surae muscles, especially the soleus. Histological studies of this triceps surae muscle tissue revealed a haphazard distribution of adipose and connective tissue, striated and smooth muscle cells, vessels and lymphoid follicles, as well as nerve bundles which, together, were considered components of a hamartoma.

Child↗

PubMed1997

[The helium-3 MRT of pulmonary ventilation: the initial clinical applications].

PURPOSE: of the study is the visualisation of normal pulmonary ventilation in healthy volunteers and the evaluation of abnormalities in patients with different lung diseases using 3He magnetic resonance imaging (3He-MRI). MATERIAL AND METHODS: Hyperpolarized 3He gas (V = 300 ml, p = 3 x 10(5) Pa, polarised to 35-45% by optical pumping, provided in special glass cells) was inhaled by eight healthy volunteers and ten patients with different lung diseases. A 3D FLASH sequence (TR = 11.8 ms; TE = 5 ms; matrix 144 x 256, FOV 350 mm, section thickness 7-10 mm, coronal orientation) was performed in a single breath-hold (22-42 s). Clinical and radiological examinations were available for correlation. RESULTS: The studies were successfully carried out in 8/8 volunteers and in 8/10 patients. The central airways were constantly visualised with intermediate to high signal intensity. The lung parenchyma of volunteers with normal ventilatory function showed rather homogeneous intermediate to high signal, whereas patients with chronic obstructive lung disease and/or pneumonia presented severe signal inhomogeneities. Space-occupying lesions and pleural effusion caused large areas with little or no signal. The represented the lesion and adjacent ventilatory disturbances whose extent had not been presumed from chest x-ray or CT. The spatial resolution was higher than in ventilation scintigraphy. CONCLUSION: 3He MRI is a promising new modality for the assessment of pulmonary ventilation and its anomalies.

Administration, Inhalation↗

PubMed1997

[Follow-up of Crohn's disease: can hydro-MRI replace fractionated gastrointestinal passage examination?].

PURPOSE: To compare the value of hydro-MRI with follow-through examinations in the follow-up of Crohn's disease. METHOD: 22 patients known to be suffering from Crohn's disease were examined via 1.5 T-MR system; an oral contrast examination using 1000 ml of a 2.5% mannitol solution was performed in all patients. T2-weighted TSE sequences and T1-weighted SE sequences were performed before and after the intravenous injection of Gd-DTPA. To reduce movement artifacts caused by peristalsis of the gut, intravenous injection of 40 mg Buscopan was given. The findings of hydro-MRI were compared with the follow-through examinations. RESULTS: In the upper gastrointestinal tract, the follow-through examination showed clear advantages compared with hydro-MRI for the demonstration of inflammatory changes in the gut; Hydro-MRI was, however, somewhat more reliable in the ileum and colon. It was also more sensitive than the follow-through for the demonstration of enteric fistulae (four as compared with two cases), and in demonstration extraluminal changes (free fluid in six against zero, and inflammatory adherent loops (four against zero)). Amongst the 22 patients, hydro-MRI was equal (in 10) or better (in 8) than the follow-through examination for demonstrating the intestinal manifestations of Crohn's disease, and follow-through was better in only four. CONCLUSION: For follow-up of Crohn's disease, hydro-MRI is at least as good as follow-through examination, and is even preferable, because of the absence of radiation exposure of the usually young patients.

Administration, Oral↗

PubMed1997

[Computerized tomography of the epiphyseal union of the medial clavicle: an auxiliary method of age determination during adolescence and the 3d decade of life?].

PURPOSE: To establish a reference population for the stages of epiphyseal union of the medical clavicle determined by CT. MATERIAL AND METHODS: Retrospectively, the thoracic CTs of patients under 30 years of age were reevaluated. Basic conditions were the lack of a bone development disorder and a sufficient assessment of the medial clavicle in a bone window setting. The stages of epiphyseal union were categorized as follows: Stage 1 refers to nonunion without ossification of the epiphysis, Stage 2 to nonunion with a separate and ossified epiphysis, Stage 3 to partial, and Stage 4 to complete union. RESULTS: Up to now, 279 individuals could be included in the study. Stage 1 was observed till age 16, Stage 2 occurred from ages 13 through 22, Stage 3 was found from ages 16 through 26. Stage 4 was first noted at age 22, and in 100% of the sample at age 27. CONCLUSIONS: CT is well suitable to determine the stages of epiphyseal union of the medial clavicle. It may become a generally accepted method of age identification during adolescence and the 3rd decade of life. The presented data serve as a reference population at least for white Europeans.

Adolescent↗

PubMed1997

[Radiological changes after implantation of 2 different cementless hip prostheses].

PURPOSE: Of the study was to evaluate radiological alterations of the femoral bone after implantation of two different prostheses. METHODS: 81 patients with 87 hips underwent total hip arthroplasty by using the Zweymüller-stem fixating in the medullary canal, and 175 patients with 182 ABG-stems with a proximally fixating, anatomical design were followed up clinically and radiologically. RESULTS: Adaptive bone remodelling in Zweymüller-stems showed in some patients thickening of the cortex of the femur and proximal bone-stock loss; reactive lines were seen in the proximal areas surrounding the prosthesis. Radiographs of patients with ABG-stems showed these lines in the distal, smooth part of the prosthesis and cancellous densification occurred in the area of load transfer distal to the trochanteric region. CONCLUSION: Typical x-ray findings due to various stem designs were identified and can be transferred to other cementless prostheses and should be considered if there is a suspicion of aseptic loosening.

Biomechanical Phenomena↗

PubMed1997

[Traumatic thrombosis of the distal ulnar artery (hypothenar hammer syndrome) in a golf player with an accessory muscle loop around Guyon's canal. Case report].

Arteriography of a 34-year-old golf player with M. Raynaud symptoms of his left hand revealed filling defects in the digital arteries II to IV fingers associated with corkscrew-like configuration of the ulnar artery in Guyon's space. The preoperative workup including 50 clinical laboratory tests searching for connective tissue diseases, vasculitis, and haematological disorders was without pathological findings; more central embolic sources were excluded angio- and cardiologically. MRI-scan demonstrated an anomalous muscle at the level of the hamate hook located underneath the M. palmaris brevis forming a sling around the ulnar artery. Surgery showed the ulnar artery distal to the anomalous muscle dilated with fibrotic thickening and intraluminal thrombosis. The involved A. ulnaris segment was resected and an interpositional vein graft performed. Histopathologic sections showed fibrosis of the arterial wall with intraluminal thrombosis and elastica fragmentation indicating traumatic genesis (hypothenar-hammer syndrome). We suspect intensive golf playing with the grip style and repetitive movements leading to pressure injury of the hypothenar area and the underlying ulnar artery. Contraction of the anomalous muscle belly may have additionally compressed the artery slowing down the arterial flow and accelerating the thrombosis.

Adult↗

PubMed1996

Hypothenar hammer syndrome in sports.

Repetitive blunt trauma or single severe trauma to the hypothenar region may lead to traumatic thrombosis of the distal ulnar artery (hypothenar hammer syndrome, HHS). In the sports-related literature we found and analysed isolated cases attributed to injuries sustained during sporting activities such as baseball, badminton, handball, football, frisbee, softball, karate, weight-lifting and hockey. Further, we report the case of an amateur golf player with ischaemic symptoms of his left hand, where angiography revealed filling defects in the digital arteries associated with a corkscrew-like configuration of the distal ulnar artery. Magnetic resonance imaging (MRI) scan demonstrated, at the level of the hamulus ossis hamati, accessory fibres of m. palmaris brevis forming a sling around the ulnar artery. Treatment by resection of the thrombosed a. ulnaris segment and replacement with an autologous vein graft resulted in complete relief of symptoms. Histological sections revealed partially organized thrombi adherent to the intimal surface with fragmentation of the internal elastic membrane, indicating a traumatic genesis. As the mechanism of injury, we suspected intensive golf playing with the grip style and subsequent motions leading to pressure injury of the hypothenar area and the underlying ulnar artery. Contraction of the anomalous muscle belly may have additionally compressed the artery, slowing down the arterial flow and promoting thrombosis. In most reported cases including our own, it took a relatively long time until the cause of the disease as traumatic was found and accepted. The initial repetitive blunt or single severe trauma initiating the HHS can easily be overlooked or ignored. After intimal damage of a. ulnaris, the beginning of symptoms may be prolonged and mislead one into thinking the cause is a collagen or vasospastic disease.

Adult↗

PubMed1996

Normal and abnormal pulmonary ventilation: visualization at hyperpolarized He-3 MR imaging.

To assess the feasibility of helium-3 magnetic resonance (MR) imaging with a three-dimensional fast low-angle shot (FLASH) sequence, He-3 gas (volume, 300 mL; pressure, 3 x 10(5) Pa; polarized up to 45% by means of optimal pumping) was inhaled by five healthy volunteers and five patients with pulmonary diseases. All breath-hold examinations (22-42 seconds) were completed successfully. Normal ventilation was depicted with homogeneous high signal intensity, lesions were depicted as causing defects, and obstructive lung disease was depicted with severely inhomogeneous signal intensity.

Administration, Inhalation↗

PubMed1996

[Synovial sarcoma of the foot].

The case of a 29 year-old female patient who had experienced pain in the right midfoot for 5 years which was diagnosed as a degenerative or rheumatic change and treated by physiotherapy and medication. By means of magnetic resonance imaging we identified a soft-tissue tumor of the midfoot. Histology provided the findings of a monophasic fibrous synovial sarcoma. The case history is reported together with a presentation of the disease and its radiological diagnosis.

Adult↗

PubMed1995

[The magnetic resonance tomographic findings following the resection arthroplasty of the caput humeri].

PURPOSE: The resection of the humeral head is normally carried out only with respect to four-part and dislocation fractures in elderly patients. The purpose of this study was to examine whether there is a correlation between the clinical results and the MRI findings. MATERIAL AND METHODS: 8 patients underwent clinical and MR examination two to 6 years after resection. RESULTS: A cartilage-like tissue formation between the remaining humeral head and the glenoid fossa, with signal intensities comparable to hyalin cartilage was found in all patients. CONCLUSION: The good functional results following resectional surgery of the humeral head can partially be related to new substitute cartilage resulting from a chondroid metaplasia.

Aged↗

PubMed1995

[The value of MR tomography in traumatic patella dislocations].

PURPOSE: To describe the MR imaging findings in patients with lateral patellar dislocation. MATERIAL AND METHODS: The MRIs of 31 patients with patellar dislocation were evaluated retrospectively. Arthroscopic surgery was performed in 23 cases. RESULTS: Hemarthrosis was found in 30/31, contusions of the lateral femoral condyle in 30/31 and of the medial patellar facet in 26/31 cases. Injury of the medial patellar retinaculum was seen in 28/31 cases. Osteochondral fractures were found in 18 patients; compared to arthroscopy there were one false-positive and 5 false-negative findings concerning loose cartilage bodies. In 7 cases, patellar dislocation was not suspected before MR imaging. CONCLUSION: Hemarthrosis, lateral femoral and medial patellar contusion, and retinacular disruption are typical findings after lateral patellar dislocation. A careful search for free osteochondral fragments is mandatory as it influences the indication and performance of arthroscopic surgery.

Adolescent↗

PubMed1995

[MRI studies on the distensibility of cruciate ligaments of healthy knee joint].

AIM: Examination of the distensibility of the cruciate ligaments to evaluate the tense plasty of the cruciate ligaments. MATERIAL AND METHOD: A functional MR study was performed using a Magnetom Open (0.2 Tesla, Fa. Siemens). We measured the length and width of the anterior and posterior cruciate ligament in volunteers (n = 12), age 20-40. We examined in 4 knee positions between maximal extension and maximal flexion. RESULTS: Using the Wilcoxon test, the statistics do not show any significant difference between the length and width of the cruciate ligaments in the monoxial movement. CONCLUSION: Our results may support the operative tense plasty of the cruciate ligaments although the entire complex mechanical system has not been examined.

Adult↗