Visualization of injection depot after subcutaneous administration by syringe and needle-free device (Medi-Jector): first results with magnetic resonance imaging.
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Adult↗
Biomedical subjects
G Brinkmann
Publications and source records attributed to G Brinkmann.
[MR angiography of pelvic arteries].
During the last years, magnetic resonance angiography (MRA) has become a widely used modality for intracerebral and carotid artery imaging. Due to technical limitations, the clinical impact of MRA in the iliofemoral arteries has been rather poor. New developments in MRA like ECG-triggered sequences and the occurrence of contrast-enhanced MRA has overcome most of these limitations. Therefore, a major advance in clinical use of these diagnostic tools can be predicted. This paper discussed the advantages of ECG-gated 2D-Phase contrast, ECG-gated 2D-Time-of-Flight and contrast enhanced FLASH 3D angiography sequences from a clinical point of view. 2D-PC-MRA is a robust technique, which provides an overview of the iliofemoral artery system in less than 5 minutes. Limitations are the true 2D impression of the sequence and the partial venous overlay. 2D-TOF-MRA on the other hand is time consuming, however it enables 3D reconstruction and effective venous suppression can be applied. Contrast enhanced MRA as the third sequence discussed provides high resolution images in less than 30 sec. However contrast bolus timing might be a problem. In conclusion the authors suggest a combination of 2D-PC-MRA and additional 2D-TOF sequences at questionable vascular areas as the modality of choice, due to the fact, that MRA of the iliofemoral arteries ist mostly only one step of a complete lower limb examination. Contrast MRA might become the method of choice in the future however problems with multiple contrast injections and upper limits of contrast dose have to be solved.
Adult↗
MRI of the nasal cavity, the paranasal sinuses and orbits in Wegener's granulomatosis.
The purpose of this study was to evaluate diagnostic MRI criteria in Wegener's granulomatosis of the nasal cavity, the paranasal sinuses and orbits. Between March 1991 and January 1996, 62 patients with biopsy-proven Wegener's granulomatosis were studied with T1- and T2-weighted spin-echo (SE) sequences. In 32 patients coronal postcontrast T1-weighted images were obtained. Mucosal thickening of the nasal cavity and paranasal sinuses was demonstrated as high-intensity lesions on T2-weighted SE sequences in 57 patients (92%). Of this group, inflammatory granulomatous tissue was found on biopsy in 30 patients (48%) in the nasal cavity and in 4 patients (6%) in the paranasal sinuses. In 23 patients (37%) biopsy revealed unspecific inflammatory changes without evidence of granulomatous tissue. In 14 patients (23%) granulomas were depicted as low-signal intensity lesions on T1- and T2-weighted SE sequences in the paranasal sinuses and orbits. In 5 patients (8%) osseous destruction was found. After gadolinium injection, 12 of 14 granulomas showed inhomogeneous signal enhancement. In two granulomas no enhancement was found. The MRI technique is helpful in the diagnosis of patients with Wegener's granulomatosis. In the initial inflammatory process of Wegener's granulomatosis, it is not possible to differentiate between mucosal inflammation and granulomatous tissue in MRI. In the later stage of granulomatous transformation, granulomas can be depicted as low-signal-intensity lesions. Therefore, Wegener's granulomatosis should be included in the differential diagnosis of patients with low-signal-intensity lesions on T1- and T2-weighted SE sequences of the nasal cavity, paranasal sinuses and orbits.
Adult↗
[Thoracic manifestations of osteosarcoma].
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Adolescent↗
[Magnetic resonance tomography in the diagnosis of mandibular osteomyelitis].
PURPOSE: A prospective study of the value of MRI in the diagnosis of osteomyelitis of the mandible with special reference to the suitability of different MR sequences. MATERIAL AND METHODS: In 13 patients, average age 55 years (12-82), with clinical suspicion of osteomyelitis of the mandible, 18 MRI examinations were carried out (STIR, TSE T2, proton and SE T1 weighted scans with and without contrast, slice thickness 3.5 to 6 mm). Image quality of the sequences was evaluated as well as the suitability of the various sequences for showing the lesion, its location and extent. Activity of the osteomyelitis was judged by the degree of contrast uptake and was correlated with 3-phase bone scintigraphy and with histological findings. RESULTS: In 9 of the 14 cases the findings on MRI and of the scintigraphy agreed with the histology. In two patients the activity of the inflammatory process was exaggerated by the MRI. In another follow-up examination it was slightly underestimated. All lesions were shown to be highly active by the histology were recognized as such by MRI. For the localisation and recognition of the extent of the inflammatory processes STIR sequences and T1 weighted non-enhanced SE sequences proved the most suitable. Contrast medium is essential to evaluate the inflammatory activity. CONCLUSION: MRI is a sensitive diagnostic method; it is as good as 3-phase bone scintigraphy in demonstrating osteomyelitis of the mandible and of its activity but is superior for showing the pathological anatomy.
Adolescent↗
[Comparison of T2-weighted turbo spin-echo and ultrafast HASTE sequence in the diagnosis of cervical myelopathies and spinal stenoses and static and kinematic MRT of the spine].
PURPOSE: The purpose of this study was to compare HASTE-sequence with T2-weighted TSE-sequence in the detection of cervical myelopathy and cervical spinal stenosis in kinematic MRI. METHODS: 24 patients with degenerative disease of the cervical spine were studied. Images were evaluated according to the following criteria: artifacts, delineation of the vertebra, disks and degenerative changes, grade of spinal stenosis (grade 0-3) and evaluation of the cervical spinal cord. RESULTS: Due to image blurring and artifacts, evaluation and delineation of the cervical spine was possible in all cases in the T2-weighted TSE-sequence, but only in 23 of 24 patients using HASTE-sequence. Differentiation between osteophytes and disks was obtained in most cases (23/24) in the T2-weighted TSE-sequence but none in the HASTE-sequence. Cervical myelopathy was observed in 4 patients in T2-weighted TSE images but only in two cases using HASTE-sequence. Compared to T2-weighted TSE-sequence spinal canal stenosis was underestimated using HASTE-sequence. CONCLUSION: T2-TSE-sequence is superior to HASTE-sequence in the delineation of anatomical structures of the cervical spine, the grading of cervical spinal stenosis and the evaluation of cervical myelopathy.
Adult↗
Kinematic MR imaging of the ankle--initial results with ultra-fast sequence imaging.
PURPOSE: In order to evaluate the advantages of ultra-fast MR sequences, kinematic MR imaging studies were performed in 4 patients with osteochondritis dissecans of the talus and in 12 healthy volunteers. MATERIAL AND METHODS: The patients and volunteers were placed inside a custom-made positioning device. Sagittal ultra-fast T2-weighted turbo gradient-echo sequences and HASTE sequences were obtained during active joint motion from dorsiflexion to plantar flexion. Eight sagittal slices were scanned separately to cover this ankle motion. In each slice, 8 to 10 images were obtained in 12-s or 18-s periods. RESULTS: Adequate image quality for analyzing the normal kinematics of the ankle was obtained in all subjects. At surgery, the osteochondral fragment was found to be mobile in 3 of the 4 of the patients. In none of these cases was fragment mobility observed on kinematic MR imaging. No motion of the fragments was observed in the fourth patient, neither at surgery nor on kinematic MR imaging. CONCLUSION: Ultra-fast MR imaging sequences made it possible to produce kinematic MR imaging studies of active joint motion. The positioning device was useful for guiding joint motion in patients and for obtaining adequate image quality.
Adult↗
The total entropy for evaluating 31P-magnetic resonance spectra of the liver in healthy volunteers and patients with metastases.
RATIONALE AND OBJECTIVES: The authors describe the clinical status of liver tissue with only a single numerical quantity (total entropy) derived from spectroscopic data of 31P-magnetic resonance (MR) spectra. METHODS: Twenty-four patients with liver metastases and 20 volunteers were investigated with image-guided volume selective 31P-MR spectroscopy on a 1.5-T whole body scanner. From each in vivo 31P-MR spectrum, the ratios of phosphomonoester (PME)/beta-adenosine triphosphate (ATP), inorganic phosphate (Pi)/beta-ATP and phosphodiester (PDE)/ beta-ATP and the total entropy (H*) were calculated. Mean values and standard deviations were determined and significance of the differences were tested with Student's t test. RESULTS: For patients, the H* = 4.7 +/- 4.3, PME/beta-ATP 0.72 +/- 0.28, Pi/beta-ATP = 1.00 +/- 0.39, PDE/beta-ATP = 1.68 +/- 0.59. For the volunteers, H* = 7.6 +/- 2.5, PME/beta-ATP = 0.39 +/- 0.15, Pi/beta-ATP = 0.90 +/- 0.19, PDE/beta-ATP = 1.25 +/- 0.28. The total entropy of patients' spectra showed significantly lower values compared with those of volunteers. PME/beta-ATP and PDE/beta-ATP of the patients increased and differed significantly from volunteer data. CONCLUSIONS: It was demonstrated that the results of in vivo 31P-MR spectroscopy may be described with a single criterion by means of the total entropy.
Adenosine Triphosphate↗
Management of the difficult airway. A case of failed fiberoptic intubation.
BACKGROUND: Fiberoptic intubation is the current gold standard for the management of difficult intubation. Nevertheless, in rare circumstances even fiberoptic intubation fails. METHODS: We describe the case of a female patient suffering from neurofibromatosis Recklinghausen and a giant malignant schwannoma on the neck obstructing the pharynx and compromising respiration. Based on the clinical presentation and the MRI findings, difficulties in airway management were anticipated and fiberoptic intubation of the awake patient was planned. RESULTS: After localizing the vocal cords it was not possible to advance the tube into the trachea due to the severe deviation of the glottis. A decision was made to cancel any further fiberoptic intubation attempts and a conventional tracheotomy was performed under local anaesthesia without problems. CONCLUSION: This case illustrates that even awake fiberoptic intubation has its failure rate, due to inability to visualize the larynx, inability to advance the tube over the fiberscope (as in the present case), or inability to direct the tube towards the larynx. Due to the extreme deviation of the larynx other established techniques for difficult intubation were not deemed appropriate in this case. Therefore, weighing the risks and benefits, a decision was made to perform a tracheotomy under local anaesthesia.
Airway Obstruction↗
Cardiac-gated two-dimensional phase-contrast MR angiography of lower extremity occlusive disease.
OBJECTIVE: The purpose of this study was to evaluate our capability to use coronally acquired, cardiac-gated two-dimensional phase-contrast MR angiography (MRA) to correctly detect and grade arteriosclerotic lesions from the aortic bifurcation to the popliteal artery. SUBJECTS AND METHODS: One hundred fifteen patients with a total of 253 arteriosclerotic lesions proven by intraarterial digital subtraction angiography were examined prospectively by two-dimensional phase-contrast MRA. MRA was performed from the aortic bifurcation to the popliteal trifurcation. Imaging parameters were TR/TE, 83/9 msec; flip angle, 11 degrees; matrix, 256 x 192; acquisitions, two; slice thickness, 80 mm; and field of view, 320 mm. ECG gating was used routinely and eight to 10 phases were acquired during the cardiac cycle. Velocity encoding was set to 30 cm/sec in the iliac arteries and to 20 cm/sec in the femoral and popliteal arteries. Detected stenoses were graded in the following manner: 1% to less than 50% stenosis, group 1; 50% to less than 75% stenosis, group 2; 75% to less than 100% stenosis, group 3; and total occlusion, group 4. RESULTS: All arteriosclerotic lesions were revealed by MRA. Two hundred seventeen of 253 lesions were also graded correctly. Sensitivity was 95%, specificity was 90%, positive predictive value was 90%, and negative predictive value was 96%. The weighted kappa index was (.92). Sensitivity and specificity for occlusions were both 100%; for high-grade stenoses, 94% and 91%, respectively; for moderate stenoses, 84% and 94%, respectively; and for mild stenoses, 79% and 100%, respectively. CONCLUSION: Two-dimensional phase-contrast MRA can provide MR angiograms with high sensitivity and specificity for high-grade stenoses in a reasonable amount of time in patients with peripheral artery occlusive disease.
Adult↗
Influence of different fasting periods on P-31-MR-spectroscopy of the liver in normals and patients with liver metastases.
The purpose of this study was to determine the influence of different fasting periods on the in vivo P-31-MR spectroscopy of the healthy liver and patients with liver metastases. Image-guided localized P-31-MRS was performed in 24 patients with liver metastases and in 20 healthy volunteers. The spectra were obtained with a whole body scanner operating at 1.5 T using a surface coil. The P-31-MRS was performed after a fasting period of 3-5 h (group 1) and after overnight fasting (group 2). The PME/beta-NTP, PDE/beta-NTP and Pi/beta-NTP were calculated from P-31-MR spectra and were compared in relation to the nutrition status of the volunteers and patients. The PME/beta-NTP and PDE/beta-NTP were significantly increased in spectra of patients with metastases. There were no significant changes in the ratios of phosphorus metabolites in healthy liver tissue or in liver metastases after a fasting period of 3-5 h as compared with overnight fasting.
Adult↗
[Preoperative differential diagnosis of cystic adnexal tumors: double-contrast MRT].
PURPOSE: Preoperative assessment of adnexal lesions as benign or malignant by MRI with gastrointestinal and intravenous contrast. METHODS: 46 patients with benign (n = 42) and malignant (n = 4) cystic adnexal tumours underwent MRI of the pelvis. Transaxial and coronal images were acquired using conventional T1- and T2-weighted SE-sequences after oral administration of superparamagnetic iron oxide particles (Ferristene). Additional T1-weighted SE-images were obtained immediately following gadodiamide (Gd DTPA-BMA) injection. RESULTS: MRI correctly classified the four malignant lesions, whereas nine histologically benign lesions were misdiagnosed as malignant. Intravenous contrast yielded a superior delineation of intratumor architecture. CONCLUSION: Due to exclusion of solid structures. MRI with oral and i.v. contrast enables to dismiss suspected malignity in cystic adnexal lesions. Because of the non-specificity of the macroscopic criteria of dignity, the MR diagnosis "malignity" is of limited value.
Adenocarcinoma↗
[MR angiography of the carotid arteries using 3D TOF technique with sagittal double-volume acquisition using a new head-neck coil].
PURPOSE: The aim of the study was to assess the value of MR angiography (MRA) in sagittal technique compared to DSA in the evaluation of carotid artery stenosis. METHODS: 80 carotid arteries in 40 symptomatic patients were prospectively studied with DSA and MRA. MRA was carried out by means of 3 D time-of-flight technique with a FISP sequence (TE6 ms/TR80 ms, flip angle 25 degrees, FOV 240 x 210 mm, matrix 157 x 256 mm, in-plane resolution 1.34 x 0.94 mm, partition thickness 1.32 mm, slab thickness 45 mm, acquisition time 7 min) using a new head-neck coll. Data acquisition was performed in sagittal orientation with the "double-slab" technique. Imaging quality of the extracranial carotid arteries and correctness of quantification of stenosis was performed. RESULTS: Imaging quality was good at the origin of the carotid arteries in 65%, at the bifurcation region in 98% and near the skull base in 81%. The agreement of DSA and MRA was 96% of the normal arteries (24/25), 90% of the severe stenoses (28/31) and 100% of the occluded arteries (9/9). CONCLUSION: MRA in sagittal "double-slab" technique is a noninvasive technique allowing to detect normal arteries and candidates for surgery with a high degree of certainty.
Adult↗
Spiral CT angiography and selective digital subtraction angiography of internal carotid artery stenosis.
PURPOSE: To determine whether spiral CT angiography allows accurate, quantitative evaluation of anatomic abnormalities, including detection of additional lesions, delineation of plaque morphology, and estimation of degree of internal carotid artery stenosis. METHODS: Spiral CT angiography with a maximum intensity projection technique was compared with selective digital subtraction angiography (DSA) in 92 carotid arteries. The category of stenosis was determined according to the North American Symptomatic Carotid Endarterectomy Trial: mild (0% to 29%), moderate (30% to 69%), severe (70% to 99%), and occlusion (100%). RESULTS: In 78 (85%) of the 92 cases, spiral CT angiography and selective DSA demonstrated the same degree of stenosis. All occlusions (n = 19) were diagnosed correctly with spiral CT angiography. Spiral CT angiography agreed with selective DSA in the classification of stenosis in 59% of the group with mild stenosis, in 82% of the group with moderate stenosis, and in 90% of the group with severe stenosis. In the groups with mild (n = 13), moderate (n = 9), and severe (n = 27) stenosis, correlation of spiral CT angiography with selective DSA was significant. Calcified plaques were readily diagnosed with the use of spiral CT angiography but delineation of ulcers was poor. Tandem lesions were not visible owing to the limited coverage. CONCLUSION: Spiral CT angiography is useful for the detection of proximal internal carotid stenoses that are greater than 30%. Depiction of mild stenoses appears to be limited. CT is superior for the detection of calcified plaques but it is not useful for the detection of ulcers.
Adult↗
[CT and PRI angiographic findings in dissection of the neck arteries].
PURPOSE: To determine the usefulness of CT angiography (CTA) and MR angiography (MRA) for evaluation of dissection in cervical vessels. MATERIAL AND METHODS: Dissection of cervical vessels was revealed by conventional angiography in 4 patients (two female, two male) of 30-62 years of age. Dissection was located in the carotid artery (n = 3) and in the vertebral artery (n = 1). In two patients CTA and in two patients MRA was performed. RESULTS: Diagnosis of dissection was possible by CTA (internal carotid artery: n = 2) and by MRA (internal carotid artery and vertebral artery). Imaging of the dissection membrane of the vessel wall was possible in one case with MRA. CONCLUSION: CT and MR angiography was successful for detection of typical morphology of dissection in all cases. If results in a greater number can be obtained it seems to be conceivable that both methods can be used in primary diagnosis.
Adult↗
Cine MR imaging before and after realignment surgery for patellar maltracking -- comparison with axial radiographs.
OBJECTIVE: Comparison of motion-triggered cine magnetic resonance (MR) imaging and conventional radiographs for the assessment of operative results of patellar realignment. SUBJECTS AND METHODS: Fifteen patients with recurrent patellar dislocation or patellar subluxation were evaluated with conventional axial radiographs before and after realignment surgery by measuring the congruence angle (CA), lateral patellofemoral angle (LPFA), and lateral displacement (d). In eight patients the patellofemoral joint was additionally evaluated pre- and postoperatively with motion-triggered cine MR imaging by determining the bisect offset (BSO), lateral patellar displacement (LPD), and patellar tilt angle (PTA). RESULTS AND CONCLUSIONS: Significant differences between the pre- and postoperative measurements were found for all MR imaging parameters (BSO, LPD, PTA: p<0.01) but not for the conventional X-ray parameters (CA: p = 0.70, LPFA: p = 0.56; d: p = 0.04). Motion-triggered cine MR imaging was superior to conventional tangential radiographs for assessing the effectiveness of patellar realignment surgery.
Adolescent↗
[Quantitative computed tomography of the lung in the early diagnosis of asbestosis: initial results in asbestos-exposed navy personnel].
AIM: To evaluate the diagnostic role of respiratory gated quantitative CT of the lung with regard to the early detection of asbestos-induced lung fibrosis. MATERIAL AND METHODS: 29 navy personnel with a mean asbestos exposure of 21.3 years and exclusively low profusion stages with regard to plain film X-ray (0/1 and 1/0, ILO 1980) were examined using high resolution CT and respiratory gated quantitative CT of the lung. RESULTS: A low but significant increase of the global lung density with -816 HU (range -844 to -749 HU) was found in comparison with the age-matched reference values of -829.8 HU (range -834 to -819 HU). In individual cases the histogram analysis demonstrated a shift of the density distribution towards higher density intervals without corresponding findings in HRCT. No alterations in lung function were observed. There was no correlation between the latency period or length of exposure and density values. CONCLUSION: The respiratory gated quantitative CT of the lung may potentially develop into an accessory parameter for monitoring dust exposed personnel.
Adult↗
[Kinematic MRI in degenerative cervical spine changes].
AIM: To evaluate functional stenosis of the cervical spine, kinematic MRI was performed in 23 healthy volunteers and 23 patients with degenerative disease. MATERIAL AND METHOD: Kinematic MRI of the cervical spine was done from 50 degrees of inclination to 30 degrees of reclination. Depending on the maximum inclination and reclination the range of motion was divided into 9 equal angle positions. At each angle position sagittal T2* weighted gradient echo sequences were performed. RESULTS: In relation to the neutral position a physiological narrowing of the ventral epidural space was seen in healthy volunteers at inclination (50 degrees) in up to 50% and respectively widening at reclination (30 degrees) in up to 10%. An increase of spinal canal stenosis or even spinal cord compression was seen at inclination in 5 patients (22%) and in 15 patients (65%) at reclination. No change of spinal canal stenosis was found in three patients (13%). CONCLUSION: In patients with degenerative disease of the cervical spine kinematic MRI demonstrated in some patients functional spinal canal stenosis with myelon compression which was not seen in standard MRI. Therefore kinematic MR imaging can be recommended as a complementary examination in the early detection of functional myelon compression and in planning the further therapeutic work-up.
Adult↗