Biomedical subjects

M Heller

Publications and source records attributed to M Heller.

At least 73 records · Page 4Linked to original sources

PubMed2001

Uncommon presentation of a giant biliary cystadenoma: correlation between MRI and pathologic findings.

An uncommon case of a giant mucinous biliary cystadenoma (BCA) of the liver is described. On T2-weighted and STIR images, a large hyperintense cystic mass revealed some septations and multiple intracystic masses of similar size and shape and uniform signal intensity, which was isointense to liver parenchyma. On T1-weighted images, intracystic bodies were obscured and the cyst was hyperintense. The magnetic resonance (MR) appearance of intracystic fluid and structures was not due to mucinous or proteinous or hyperproteinous material, but corresponded to clots floating within hemorrhagic fluid.

Aged↗

PubMed2001

Quinacrine induces cytochrome c-dependent apoptotic signaling in human cervical carcinoma cells.

Quinacrine (QU), a phospholipase-A2 (PLA-2) inhibitor has been used clinically as a chemotherapeutic adjuvant. To understand the mechanisms leading to its chemotherapeutic effect, we have investigated QU-induced apoptotic signaling pathways in human cervical squamous carcinoma HeLa cells. In this study, we found that QU induced cytochrome c-dependent apoptotic signaling. The release of pro-apoptotic cytochrome c was QU concentration- and time-dependent, and preceded activation of caspase-9 and -3. Flow cytometric FACScan analysis using fluorescence intensities of DiOC6 demonstrated that QU-induced cytochrome c release was independent of mitochondrial permeability transition (MPT), since the concentrations of QU that induced cytochrome c release did not alter mitochondrial membrane potential (delta pai(m)). Moreover, kinetic analysis of caspase activities showed that cytochrome c release led to the activation of caspase-9 and downstream death effector, caspase-3. Caspase-3 inhibitor (Ac-DEVD-CHO) partially blocked QU-induced apoptosis, suggesting the importance of caspase-3 in this apoptotic signaling mechanism. Supplementation with arachidonic acid (AA) sustained caspase-3 activation induced by QU. Using inhibitors against cellular arachidonate metabolism of lipooxygenase (Nordihydroxyguaiaretic Acid, NDGA) and cyclooxygenase (5,8,11,14-Eicosatetraynoic Acid, ETYA) demonstrated that QU-induced apoptotic signaling may be dependent on its role as a PLA-2 inhibitor. Interestingly, NDGA attenuated QU-induced cytochrome c release, caspase activity as well as apoptotic cell death. The blockade of cytochrome c release by NDGA was much more effective than that attained with cyclosporin A (CsA), a MPT inhibitor. ETYA was not effective in blocking cytochrome c release, except under very high concentrations. Caspase inhibitor z-VAD blocked the release of cytochrome c suggesting that this signaling event is caspase dependent, and caspase-8 activation may be upstream of the mitochondrial events. In summary, we report that QU induced cytochrome c-dependent apoptotic signaling cascade, which may be dependent on its role as a PLA-2 inhibitor. This apoptotic mechanism induced by QU may contribute to its known chemotherapeutic effects.

Antimalarials↗

PubMed2001

Flow patterns from metallic vascular endoprostheses: in vitro results.

The aim of this study was to determine flow characteristics and pressure gradients of different balloon- and self-expandable stents in an in vitro flow-model. Seven vascular stents (Bridge, Cragg, Memotherm, Palmaz PS 784, Sinus, Symphony, Wallstent), equal in length (60 mm) and diameter (10 mm), were deployed in a closed flow model. The inner diameter of the tube measured 9 mm. Flow at 1.5 and 6 l/min was applied. Flow patterns were visualized by anionic particles illuminated with two helium-neon lasers. Late laminary flow characteristics and pre-/post-stent pressure gradients were determined in either expanded stent, 25 and 50% tube stenosis. Stent implantation induced a decrease of laminary flow when compared with an unstented tube with and without concentric 25% stenosis (p < 0.01) at all flow rates and an increase of pressure gradients when compared with an unstented tube for a flow rate of 6 l/min and all stenoses (p < 0.01). At 1.5 l/min most stents revealed no significant change of pressure gradient, the highest gradient measured 4.0 mmHg. Sinus permitted maximum (expanded: 82.1% and 76.9% at 25% stenosis at 1.5 l/min; p < 0.01) and Palmaz minimum of laminary flow at all flow rates and stenoses (70.2 and 52.4% at 25% stenosis at 1.5 l/min; p < 0.01). At 6 l/min, when completely expanded, Sinus is equal to Bridge and Memotherm; in 25% stenosis Sinus is equal to Bridge, Memotherm, and additionally to Cragg and Wall. None of the endoprostheses revealed laminary flow at 50% stenosis. Inadequate stent deployment bears the risk of creating less laminary flow and pressure gradients. Since flow disturbances and pressure gradients may influence neointimal hyperplasia, stent design and completeness of stent expansion are important factors regarding the appearance of thrombus formation and postinterventional restenosis.

Arteries↗

PubMed2001

[Vasculitis--interdisciplinary diagnosis: radiology].

Determination of disease extension and disease activity are in the foreground of diagnostic imaging in vasculitides. There are several radiologic modalities available each having specific indications. Magnetic resonance imaging (MRI) readily depicts granulomas and mucosal inflammations in the paranasal sinuses, nasal cavity and orbits. Computed tomography detects osseous lesions of the skull. Due to its superb sensitivity MRI is an established screening modality for CNS vasculitides, although there are limitations with regard to specificity. In spite of its limited accuracy in most institutions angiography is still required for radiological confirmation of CNS vasculitis. Perfusion and diffusion MR-imaging may combine the advantages of 'conventional' MRI and angiography. By now the method is not fully validated for vasculitides, however. Vascular disease in Takayasu's arteritis and in giant cell arteritis involving predominantly large and medium sized vessels is readily diagnosed by non invasive magnetic resonance angiography. Percutaneous transluminal angioplasty has proven to be an effective and save therapeutic modality for the cure of vascular stenoses and occlusions. Plain film radiography in two planes is the established modality for pulmonary imaging. In pulmonary vasculitides a more thorough analysis of lung disease is provided by high resolution computed tomography. Diagnostic imaging does substantially assist in the interdisciplinary management of patients suffering from vasculitides.

Angioplasty↗

PubMed2001

Regional lean body mass and resting energy expenditure in non-obese adults.

OBJECTIVE: To study the effect of regional lean body mass (LBM) on resting energy expenditure (REE). Design Cross-sectional study in a homogenous group of 26 young healthy non-obese subjects. METHODS: Regional body composition was assessed by dual-energy X-ray absorptiometry (DEXA). REE was measured by indirect calorimetry. RESULTS: REE showed positive relationships with whole body LBM (LBMb; r=0.89) as well as with regional LBM (LBMtrunk = LBMt, r = 0.88, and LBMarms+legs = LBMe for LBMextremities, r = 0.89) with non-zero intercepts (between 1.86 and 2.83 MJ/d). REE per kg LBMb falls as LBMb increases (r = 0.77). By contrast, REE adjusted for regional distribution of LBM (i. e. the ratio of LBMt to LBMe) increases as LBMb increases (r = 0.91) showing a near-zero intercept (i. e. 0.048 MJ/d). Adjusting REE for LBMb as well as for the ratio of LBMt to LBMe can be used for comparison between subjects. CONCLUSIONS: Our data suggest that regional distribution of LBM is a determinant of REE. Assessment of LBMt and LBMe by DEXA provides a possibility to adjust for the non-linearity of REE on LBMb.

Absorptiometry, Photon↗

PubMed2001

Evaluation of hydroxyapatite implants in vertebral bodies and extremities by contrast-enhanced magnetic resonance imaging.

This pilot study evaluated hydroxyapatite (HA) implants (Endobon) into bone with magnetic resonance imaging (MRI). Nineteen patients (median age 57 years; range 18-67 years) have been evaluated. Eight received granulated HA into vertebral bodies after trauma, while 11 received HA blocks into extremity bones after trauma (n = 8) or fibrous dysplasia (n = 2). In a 1.5-T MR scanner, transversal T1-weighted, flash, 2-dimensional images were obtained. Signal intensities were measured in regions of interest (ROI) from the centre and periphery of HA, trabecular bone, fat and air before and after gadolinium (Gd) contrast enhancement, and the signal-to-noise ratio (SNR) was calculated. After Gd application the SNR in HA increased significantly, peripherally (11.7 without vs 18.2 with Gd, P = 0.003) more than in the centre (7.9 without vs 11.9 with Gd, P = 0.007). The SNR of the HA was higher in patients with block implants compared with granulated HA (P > 0.008). After Gd application, granulated HA enhances significantly less than HA blocks. During insertion of HA, the granulated form is compressed more and is therefore more compact than the HA block. This might hinder integration into the bone structure and the blood supply. SNR of the HA margin was higher than centrally, which might be due to granulomatous tissue after trauma and/or operation or beginning marginal integration.

Adolescent↗

PubMed2001

Magnetic resonance arthrography of the acetabular labrum: value of radial reconstructions.

The intention was to compare the sensitivity and specificity of radial planes with oblique coronal and oblique axial planes for the detection of labral abnormalities of the acetabulum on magnetic resonance arthrography (MRa). Twenty cadaveric hip joints were examined by radiography and MRa. For MRa, 15 ml of a solution of iodinated contrast material and gadolinium diethylene triamine tetra-acetic acid (Gd-DTPA; 100:1) were injected under fluoroscopic guidance. MRI was performed on a 1.5-T MR scanner with a fat-suppressed 3D-FLASH sequence (TR/TE/flip-angle 42 ms/10 ms/40 degrees; field of view 16 cm, matrix 256 x 256, section thickness 1.5 mm, pixel size 0.7 x 0.7 mm). Multiplanar image reconstructions were done perpendicular to the acetabulum in oblique coronal and oblique axial planes and in radial planes. Macroscopic and histopathologic examination of the labral specimens was performed. Labral lesions were found in 15/20 hips (75%) on pathologic examination. Six hips demonstrated labral degeneration. The labrum was partially detached in 7 hips and completely detached in 2 hips. A flap-like labrum was found in 2 cases, 1 with partial detachment of the labrum and 1 with a degenerated labrum. Using oblique coronal and oblique axial reconstructions, pathologic findings were confirmed by MRa in 9/15 specimens (sensitivity 60%). There were no false-positive findings (specificity 100%, accuracy 70%). Also, 3/6 labral degenerations without detachment, 4/7 partial detachments, and 2/2 complete detachments were correctly diagnosed. Two flap-like labra were not recognized. With radial reconstructions, pathologic findings were correctly confirmed in 12/15 specimens (sensitivity 80%) without false-positive findings (specificity 100%, accuracy 85%). Also, 3/6 labral degenerations without detachment, 6/7 partial detachments, 2/2 complete detachments, and 1/2 flap-like labra were correctly diagnosed. MRa of the acetabular labrum using radial reconstructions is well suited to delineate the acetabular labrum and to diagnose labral detachments. Radial reconstructions allow for perpendicular display of the whole acetabular circumference and are more accurate for the diagnosis of acetabular labral lesions, when compared with oblique coronal and oblique axial reconstructions.

Acetabulum↗

PubMed2001

Mechanical boundary conditions of fracture healing: borderline indications in the treatment of unreamed tibial nailing.

Unreamed nailing favors biology at the expense of the achievable mechanical stability. It is therefore of interest to define the limits of the clinical indications for this method. The extended usage of unreamed tibial nailing resulted in reports of an increased rate of complications, especially for the distal portion of the tibia. The goals of this work were to gain a thorough understanding of the load-sharing mechanism between unreamed nail and bone in a fractured tibia, to identify the mechanical reasons for the unfavorable clinical results, and to identify borderline indications due to biomechanical factors. In a three-dimensional finite element model of a human tibia, horizontal defects were stabilized by means of unreamed nailing for five different fracture locations, including proximal and distal borderline indications for this treatment method. The loading of the bone, the loading of the implant and the inter-fragmentary strains were computed. The findings of this study show that with all muscle and joint contact forces included, nailing leads to considerable unloading of the interlocked bone segments. Unreamed nailing of the distal defect results in an extremely low axial and high shear strain between the fragments. The results suggest that mechanical conditions are advantageous to unreamed nailing of proximal and mid-diaphyseal defects. Apart from biological reasons, clinical problems reported for distal fractures may be due to the less favorable mechanical conditions in unreamed nailing. From a biomechanical perspective, the treatment of distal tibial shaft fractures by means of unreamed nailing without additional fragment contact or without stabilizing the fibula should be carefully reconsidered.

Biomechanical Phenomena↗

PubMed2001

Hip contact forces and gait patterns from routine activities.

In vivo loads acting at the hip joint have so far only been measured in few patients and without detailed documentation of gait data. Such information is required to test and improve wear, strength and fixation stability of hip implants. Measurements of hip contact forces with instrumented implants and synchronous analyses of gait patterns and ground reaction forces were performed in four patients during the most frequent activities of daily living. From the individual data sets an average was calculated. The paper focuses on the loading of the femoral implant component but complete data are additionally stored on an associated compact disc. It contains complete gait and hip contact force data as well as calculated muscle activities during walking and stair climbing and the frequencies of daily activities observed in hip patients. The mechanical loading and function of the hip joint and proximal femur is thereby completely documented. The average patient loaded his hip joint with 238% BW (percent of body weight) when walking at about 4 km/h and with slightly less when standing on one leg. This is below the levels previously reported for two other patients (Bergmann et al., Clinical Biomechanics 26 (1993) 969-990). When climbing upstairs the joint contact force is 251% BW which is less than 260% BW when going downstairs. Inwards torsion of the implant is probably critical for the stem fixation. On average it is 23% larger when going upstairs than during normal level walking. The inter- and intra-individual variations during stair climbing are large and the highest torque values are 83% larger than during normal walking. Because the hip joint loading during all other common activities of most hip patients are comparably small (except during stumbling), implants should mainly be tested with loading conditions that mimic walking and stair climbing.

Activities of Daily Living↗

PubMed2001

Fast education: a comparison of teaching models for trauma sonography.

This study's objective was to evaluate the peritoneal dialysis and mannequin simulator models for the hands-on portion of a 4-h focused abdominal sonography for trauma (FAST) course. After an introductory lecture about trauma sonography and practice on normal models, trainees were assigned randomly to two groups. They practiced FAST on one of the two simulator models. After the didactic and hands-on portions of the seminar, FAST interpretation testing revealed mean scores of 82% and 78% for the peritoneal dialysis and mannequin simulator groups, respectively (p = 0.95). Post-course surveys demonstrated mean satisfaction scores for peritoneal dialysis and mannequin simulator models of 3.85 and 3.25, respectively, on a 4-point Likert scale (p = 0.317). A FAST educational seminar, which provides both didactic and hands-on instruction, can be completed in 4 h; the hands-on instruction phase can incorporate both normal models and abnormal simulation models, such as the peritoneal dialysis model and the multimedia mannequin simulator.

Emergency Medicine↗

PubMed2001

Randomized study to compare PTA alone versus PTA with Palmaz stent placement for femoropopliteal lesions.

PURPOSE: The purpose of this study was to evaluate whether percutaneous transluminal angioplasty (PTA) combined with Palmaz stent placement provides long-term advantages compared to PTA alone after 34 months of follow-up in the femoropopliteal region. MATERIALS AND METHODS: Thirty patients randomized to undergo PTA in combination with stent placement and 23 patients randomized to undergo PTA alone were evaluated. RESULTS: Mean follow-up (+/-SD) for the PTA group was 33.8 months (+/- 8.7) and for the Palmaz group 29.1 months (+/- 6.2), with a maximum follow-up period of 39 months for both groups. No significant differences in primary or secondary patency rates could be observed at 12 or 39 months. After 39 months, the primary patency rate for PTA alone was 68.4% and the secondary patency rate was 89.5%; the primary patency rate for PTA with stent placement was 62% and the secondary patency rate was 90%. CONCLUSIONS: The results of this study show that even after a long-term follow up of more than 3 years, PTA with stent placement in the femoropopliteal artery does not produce better results than PTA alone, although it does provide better initial luminal gain after the procedure.

Aged↗

PubMed2001

Comparison of in vitro effectiveness of mechanical thrombectomy devices.

PURPOSE: To determine the in vitro efficacy of clot removal of the following hydrodynamic thrombectomy devices: the AngioJet (AJ), Hydrolyser (HL), Oasis (OS), and Amplatz Thrombectomy Device (ATD). All devices have 6-F catheters. MATERIALS AND METHODS: Thrombectomy of 5-day-old porcine clots (n = 68; 8.5 g) was performed with the AJ without a guide wire [AJ(gw0)], with a coaxial 0.016-inch guide wire [AJ(gw.016)], and with a 0.035-inch guide wire [AJ(gw.035)]), and with the HL, OS, and ATD in an artery flow model (pulsed flow: 700 L/min) simulating the superficial femoral artery (7-mm inner tube diameter). The effluent was passed through a three-step filter system (10-1,000 microm; pressure drop: 35 mm Hg). RESULTS: Mean thrombectomy time ranged from 49 seconds (AJ(gw0)) to 88 seconds (OS; P < .001). The fluid balance with use of the AJ(gw.035) was 0.89, whereas the mean ratio of applied saline solution to aspirated fluid for the other devices was not isovolumetric (AJ(gw0), 0.8; AJ(gw.016), 0.78; HL, 0.73; OS, 0.62; P < .05). Remaining thrombus ranged in size from 8.2 mg (AJ(gw0)) to 27.3 mg (AJ(gw.035); P = .079). Hydrodynamic devices (0.6% [OS] to 0.98% [AJ(gw.016)]) caused low amounts of added emboli greater 10 microm, 100 microm, and 1,000 microm. The ATD (5.19%) caused the most extensive embolization (P < .001). CONCLUSIONS: The tested mechanical thrombectomy devices have the power for sufficient thrombectomy in vitro; however, they showed moderate differences in performance. In contrast to hydrodynamic devices, the ATD fragmentation device showed a higher peripheral embolization rate of particles larger than 1,000 microm; adjunctive in vivo treatment would probably be required.

Animals↗

PubMed2001

Treatment of infrapopliteal occlusive disease by high-speed rotational atherectomy: initial and mid-term results.

PURPOSE: To assess the effectiveness and patency rates of high-speed rotational atherectomy (HSRA) for the treatment of infrapopliteal arterial occlusive disease. MATERIAL AND METHODS: During an 18-month period, a total of 19 infrapopliteal lesions in 15 consecutive patients were treated primarily by HSRA with use of the Rotablator device. Patients were followed up with documentation of clinical symptoms, standardized treadmill exercise, and Doppler sonography at 1, 3, and 6 months. Control angiography was performed 6 months after primary treatment. RESULTS: HSRA was initially successful in 14 of 15 patients, yielding an initial technical success rate of 94%. Percutaneous treatment induced an improvement of the ankle-brachial index (ABI) from 0.6 +/- 0.09 to 0.86 +/- 0.2 after intervention (P < .0001). Doppler analysis showed a mean ABI of 0.85 +/- 0.2 (P < .001) at 1 month, 0.72 +/- 0.2 (P = .012) at 3 months, and 0.7 +/- 0.2 (P = .08) at 6 months after initial therapy. Although six patients were lost to follow-up at various times, control angiography at 6 months was carried out in nine of 15 patients, allowing direct assessment of 12 of 19 treated lesions. Among six high-grade restenoses and five total occlusions in the treated vascular segments, only one arterial lumen (of 12) remained patent without presenting a hemodynamically relevant restenosis. These results led to termination of the study. CONCLUSION: Although HSRA for the treatment of infrapopliteal occlusive disease yields a very high initial technical success rate, mid-term results are extremely poor. Therefore, HSRA cannot be recommended for primary treatment of this type of lesion.

Aged↗

PubMed2001

[Value of kinematic MRI in the evaluation of patients with exacerbated pain in cervical spine motion compared with static MRI].

OBJECTIVE: To assess the clinical value of kinematic MR imaging in patients with cervical radiculopathy and increasing symptoms after provocative maneuvers at flexion, extension, axial rotation and coupled motion of the cervical spine. METHODS: Thirty-five patients with cervical disc herniation or cervical spondylosis in whom symptoms were elicited at flexion, extension, axial rotation and coupled motion were studied inside a positioning device using T2-weighted TSE, 2D-FLASH, and reformatted 3D DESS and 3D-FISP sequences. The images were evaluated for the size of disc herniations, the foraminal size and cervical cord displacement at provocative position compared with neutral position (0 degree). In addition, the value of kinematic MR images were interpretated with regard to changes in the therapeutic procedure and intraoperative patient positioning. RESULTS: Compared with the neutral position (0 degree) a change in disc herniations was not found in any (0%) of the provocative positions. In five patients (14%) cervical cord displacement was noted at axial rotation. The foraminal size varied depending on the provocative position, increasing at flexion and decreasing at extension. CONCLUSION: Kinematic MR imaging in patients with cervical radiculopathy and increasing symptoms at provocative maneuvers provides no additional information for the therapeutic decision-making process.

Biomechanical Phenomena↗

PubMed2001

[Comparison of biphasic spiral CT and MnDPDP-enhanced MRI in the detection and characterization of liver lesions].

INTRODUCTION: To evaluate the efficacy of biphasic spiral CT and MnDPDP (Teslascan, Nycomed Amersham) enhanced MR imaging to detect and classify liver lesions. MATERIALS AND METHODS: 39 patients with known or suspected liver lesions were included into this study and examined with biphasic spiral CT and MnDPDP-enhanced MRI. 25 histological reports and 1 extreme increased serum AFP value could be obtained from 22 patients, therefore only these 26 proven lesions were included into this analysis. RESULTS: From 39 patients CT revealed in 54% (14 lesions) and MRI in 54% correct (i.e., corresponding to the histology) diagnosis. Correct CT/wrong MRT diagnosis and vice versa was present in only 2 lesions each. Differentiating into benign versus malignant lesion was successful in 73% for MRI and 77% for CT. In 81% MRI revealed the correct type of lesion (hepatocellular or non-hepatocellular) vs. 77% with CT. Sensitivity/specificity for differentiation into benign/malignant lesions was 86%/70% (MRI) and 87%/77% (CT) and for differentiation of the lesions origin 100%/80% (MRI) and 80%/75% (CT), these differences were not significant. MnDPDP-enhanced MRI showed significantly more lesions than non-enhanced MRI. CONCLUSION: MnDPDP-enhanced MRI is better than CT in differentiating hepatocellular liver lesions from non-hepatocellular lesions. After contrast enhancement with MnDPDP significantly more lesions could be evaluated in MRI. MnDPDP improves, in combination with biphasic helical CT, the diagnosis of liver lesions.

Adenoma↗

PubMed2001

[Results after placement of Memotherm stents in iliac and femoral arteries].

PURPOSE: To evaluate the effectivity, safety and midterm patency rates of iliac and femoral stent placement with the Memotherm stent (Bard-Angiomed, Karlsruhe). MATERIAL AND METHODS: In 41 patients (11 female, 30 male, mean age 63.9 years) 49 lesions were treated with 50 stents. Mean lesion length was 4.8 cm for 5 occlusions and 3.1 cm for 44 stenoses. Lesions were located in the common iliac (n = 31), the external iliac (n = 15), and the common femoral artery (n = 3). Patients were followed-up clinically, with ankle-brachial indices (ABI), and angiography. Angiographic patency rates (< or = 50% restenosis) were calculated using the Kaplan-Meier method, ABIs were compared before and after therapy with the Wilcoxon test. RESULTS: An immediate technical success was achieved in 48/49 lesions (98%, intention-to-treat). Visibility of the stent was poor. Four stent placement procedures were complicated by an advancement of the stent, which could not be corrected. A thrombosis of one stent during deployment had to be treated surgically. After a mean of 10.4 months (6-24) 33 lesions were followed-up with angiography. The primary angiographic patency rate was determined to be 89.9% after 9 months. An improvement of at least one Fontaine stage was observed in 85.4%. The mean ABI increased significantly from 0.64 to 0.84 after therapy. CONCLUSIONS: The patency rate of the Memotherm stent is comparable to that of other stent systems. The poor visibility and the advancement of the stent during deployment requires further modifications.

Aged↗

PubMed2001

[MR imaging of the articular cartilage].

MR imaging has evolved to the best non-invasive method for the evaluation of articular cartilage. MR imaging helps to understand the structure and physiology of cartilage, and to diagnose cartilage lesions. Numerous studies have shown high accuracy and reliability concerning detection of cartilage lesions and early changes in both structure and biochemistry. High contrast-to-noise ratio and high spatial resolution are essential for analysis of articular cartilage. Fat-suppressed 3D-T1 weighted gradient echo and T2-weighted fast spin echo sequences with or without fat suppression are recommended for clinical routine. In this article the anatomy and pathology of hyaline articular cartilage and the complex imaging characteristics of hyaline cartilage will be discussed.

Arthrography↗

PubMed2001

Magnetic resonance imaging of the lung with a volumetric interpolated 3D-gradient echo sequence.

OBJECTIVE: To evaluate the feasibility of a magnetic resonance imaging protocol for the lung using a volumetric interpolated 3D-gradient echo sequence (3D-GRE). SUBJECTS AND METHODS: A T(1)-weighted 3D-GRE sequence was used for volumetric interpolated breath-hold examinations ("VIBE") of the lung in twelve healthy volunteers (TR/TE 4.5/1.9 ms, flip-angle 12 degrees, matrix 502 X 512 [interpolated]). Three coronal 80 mm slabs (16 aportitions, 2.5 mm slices) were added to 3D data sets for multi-planar reformations. No contrast material was applied. Artifacts and resolution o vessel and airway structures in each lung segment were evaluated by two observers (12 volunteers, 228 lung segments). RESULTS: The protocol provided excellent images of vascular and tracheo-bronchial structures with very moderate pulsation artifacts. 224/228 lung segments were imaged with "good" (146/228) or "sufficient" quality (78/228). Segmental and sub-segmental vessels (5th order) were identified due to bright flow signal without administration of contrast material. Walls of segmental bronchi (3rd order) were delineated in all parts of the lung. CONCLUSIONS: The high spatial resolution, the excellent visualization of lung anatomy, the low rate of artifacts without respiratory triggering and the short acquisition times are clear advantages of the 3D-GRE (VI-BE) sequence compared to existing 2D-GRE strategies for MRI of the lung.

Adolescent↗