Biomedical subjects

S Miller

Publications and source records attributed to S Miller.

At least 37 records · Page 2Linked to original sources

PubMed2005

[MR angiography and determination of the flow reserve after minimal invasive direct coronary artery bypass (MIDCAB) surgery of the left internal mammary artery in comparison to multirow CT].

PURPOSE: To evaluate graft patency, flow and flow reserve in patients with minimal invasive direct coronary artery bypass (MIDCAB) of internal mammary artery (IMA) grafts using a combined MR protocol with phase-contrast technique and MR angiography. MATERIAL AND METHODS: At a 1.5T Magnetom Sonata (SIEMENS), 19 symptomatic (angina CCS I-III, intermittent thoracic discomfort, scar disorders) patients (59.9 +/- 7.9 years old) with 19 left internal mammary artery (LIMA) grafts implanted in minimal invasive technique were examined 6.9 +/- 1.5 years post surgery. Contrast enhanced MR angiography (TR 2.5 ms, TE 1 ms, flip angle 20 (o), spatial resolution 1.4 x 0.9 x 1.0 mm(3), breath hold technique, no ECG-triggering, 25 ml Gd-DTPA) was performed to assess bypass patency. Phase-contrast flow measurements with retrospective gating (TR 41 msec, TE 3.2 msec, flip angle 30 degrees , spatial resolution 1.1 x 1.1 x 5 mm(3), temporal resolution 42 msec, venc 90 cm/sec) were applied in the IMA grafts at rest and after stress induction with dipyridamole (0.56 mg/kg/BW). For comparison, graft patency was evaluated by multidetector-row computed tomography (16-row CT). In 9 patients a selective catheter angiography was performed. RESULTS: MIDCAB grafts were occluded in 4/19 patients. In 4 patients the anastomosis to LAD was highly stenotic (> 70 %) at MDCT (2 experienced investigators in consensus reading). In MRA 9 grafts could be delineated completely including the distal anastomosis to LAD (47 %). In 9 patients the distal part could not be evaluated. In patients with patent grafts (MDCT), a significant improvement of graft flow (at rest 75.4 +/- 33.3 ml/min; after stress 202.7 +/- 49.6; P < 0.002) and flow reserve (patent grafts 3.0 +/- 1.1; stenotic grafts 1.5 +/- 0.2, P < 0.02; occluded grafts 0.9 +/- 0.2, P < 0.01) after stress induction was detected. Diastolic-to-systolic peak velocity ratios (D/S-PVR) at baseline were not significant between patent and stenotic grafts. Mean flow at baseline and after stress induction and flow reserve show a high sensitivity (91/92 /83 %) and specificity (86 /100/83 %) for detection of graft stenosis. MR angiography combined with flow reserve measurements could distinguish between occluded/stenotic and patent grafts in all MIDCAB grafts. CONCLUSION: MR imaging allows combined assessment of bypass patency and flow with flow reserve in patients after MIDCAB. The protocol of this study is applicable for the evaluation of graft patency in patients after revascularization.

Blood Flow Velocity↗

PubMed2005

[MR imaging in cardiomyopathies].

According to the WHO classification, cardiomyopathies are a group of diseases which are associated with myocardial dysfunction and can be classified either as primary or secondary cardiomyopathies. Genetic disorders have been identified in certain primary cardiomyopathies, however often the etiology remains unknown. The term "secondary cardiomyopathy" is used to specify diseases with the clinical indications of a cardiomyopathy, but can be attributed to a certain pathophysiological mechanism such as exposure to toxic substances, metabolic syndromes or systemic diseases. Based on morphological and functional criteria, primary cardiomyopathies are divided into dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), arrhythmogenic right ventricular cardiomyopathy (ARVC) and restrictive cardiomyopathy (RCM). During the last two decades MR imaging has emerged to a well established diagnostic tool for the understanding and treatment of cardiomyopathies. Morphological and functional information can be achieved with a high level of accuracy and reproducibility. Tissue alteration of the myocardium can be detected assessing regional contrast enhancement, T1- and T2-signal intensities and chemical shift phenomena. This article describes characteristic aspects of MR imaging for the diagnosis of primary and secondary cardiomyopathies.

Adult↗

PubMed2005

Aortic root remodeling: functional MRI as an accurate tool for complete follow-up.

BACKGROUND: After aortic valve-sparing procedures patients should be evaluated regularly because of the risk for further disease progression in the remaining aorta as well as recurrent aortic insufficiency. The purpose of this study was to evaluate the potential of functional MRI as a single examination for complete follow-up of these patients. METHODS: Twenty-two patients with a mean age of 54 years (range 30 - 66) were prospectively examined at 1, 12, 24, 36, and 74 months postoperatively, following a Yacoub aortic root remodeling operation, using a 1.5 T MRI. The original disease was chronic aneurysm of the ascending aorta or root in 17, chronic dissection in 3, and acute dissection in 2 patients. Transverse graft diameters, regurgitant fraction, LVEDV, and cardiac index were measured using cine MRI. Results were compared to spiral computed tomography and transthoracic color Doppler echocardiography. Mean time of follow-up was 24.9 months and ranged from 1 to 74 months. RESULTS: There were 2 re-operations, 2 years after primary surgery, due to high aortic insufficiency. CT and MRI measurements of graft diameters correlated well (p = 0.4544). Mean graft diameter (mean +/- SD) was 30 +/- 3.7, 33 +/- 3.4, 36.5 +/- 1.5, 37 +/- 2.8, and 38.3 +/- 2.8 mm at 1, 12, 24, 36, and 74 months, respectively, indicating a significant increase of graft diameter (p < 0.0001). Mean regurgitant fraction as determined by MRI was 14 +/- 7, 12 +/- 9, 13 +/- 9, 15 +/- 7, and 14 +/- 9 % at 1, 12, 24, 36, and 74 months, respectively. Flow based grading of aortic insufficiency by MR imaging correlated well with color Doppler echocardiography (p < 0.0001). CONCLUSIONS: MRI provides an excellent, noninvasive, comprehensive tool for follow-up after valve-sparing aortic root reconstruction. The determination of regurgitant fraction, ventricular dimensions and functions, and graft diameters allows standardized imaging protocols with a high reproducibility, which may lead to this technique being favored for the follow-up of patients after aortic root remodeling.

Adult↗

PubMed2005

Compatible scales for progressive and additive MRI assessments of haemophilic arthropathy.

The international MRI expert subgroup of the International Prophylaxis Study Group (IPSG) has developed a consensus for magnetic resonance imaging (MRI) scales for assessment of haemophilic arthropathy. A MRI scoring scheme including a 10 step progressive scale and a 20 step additive scale with identical definitions of mutual steps is presented. Using the progressive scale, effusion/haemarthrosis can correspond to progressive scores of 1, 2, or 3, and synovial hypertrophy and/or haemosiderin deposition to 4, 5, or 6. The progressive score can be 7 or 8 if there are subchondral cysts and/or surface erosions, and it is 9 or 10 if there is loss of cartilage. Using the additive scale, synovial hypertrophy contributes 1-3 points to the additive score and haemosiderin deposition contributes 1 point. For osteochondral changes, 16 statements are evaluated as to whether they are true or false, and each true statement contributes 1 point to the additive score. The use of these two compatible scales for progressive and additive MRI assessments can facilitate international comparison of data and enhance the accumulation of experience on MRI scoring of haemophilic arthropathy.

Cartilage, Articular↗

PubMed2005

Reliability of progressive and additive MRI scoring systems for evaluation of haemophilic arthropathy in children: expert MRI Working Group of the International Prophylaxis Study Group.

Effective treatment of haemophilic arthropathy requires a detailed evaluation of joint integrity. Methodological assessment of magnetic resonance imaging (MRI) scores are needed to assure reproducibility of measurements when comparing results of clinical trials conducted in different centres. We compared the reliability of two MRI scoring systems for assessment of haemophilic arthropathy: one progressive system that displays the most severe change and one additive system that depicts osteochondral and soft tissue-related changes. A total of 47 1.5 T MRI examinations of knees (n = 21) and ankles (n = 26) of 42 haemophilic boys, age range, 22 months to 18 years, performed at different centres (Toronto, n = 20, Europe, n = 12 and Denver, n = 15) were independently reviewed by four radiologists at two occasions. Twenty-two examinations were from children <9 years and 25 from children >/=9. Sagittal and coronal gradient-echo (MPGR, 3D FLASH with fat saturation, GRASS) images were obtained. The MRI examinations of the ankle and knee studies presented with osteochondral abnormalities in 38.5% and 23.8% of the cases respectively. The two scoring systems demonstrated an excellent inter-reader [progressive, 0.88; additive (A, e, s and h components), 0.86] and intra-reader [progressive, 0.92; additive (A, e, s and h components), 0.93] reliability using intraclass correlation coefficients (ICCs). Although ICCs were slightly higher for knees when compared with ankles, and for older children when compared with younger children, all values fell within excellent inter- and intra-reader reliability categories. The two MRI scoring systems demonstrated a comparable reliability. This result constitutes the basis for further development of a combined MRI scoring system for assessment of haemophilic arthropathy, which incorporates progressive and additive components.

Adolescent↗

PubMed2005

Optometric and ophthalmic contact in elderly hip fracture patients with visual impairment.

AIM: To describe previous contact with optometry and ophthalmic services in a group of elderly patients with and without visual impairment (VI) who had fallen and sustained a fractured neck of femur. METHOD: A cross sectional study of 537 patients aged 65 and over who had undergone hip fracture surgery in four Scottish centres (Glasgow, Ayr, Dundee and Fife). All patients had an in-depth optometric history, ophthalmic history and examination. RESULTS: Three hundred and ninety-three (79%) patients reported optometric contact in the 3 years preceding surgery and 107 (21%) patients had not seen an optometrist for more than 3 years. In the latter group, 64 had VI, which was due to uncorrected refractive error in 17 (27%) and untreated cataract in 20 (31%). VI (best binocular visual acuity of 6/18 or less) was found in 239 (46%) patients. A past ophthalmic history was present in 257 (50%) patients. Only 39 (16%) patients with VI were under ophthalmic care at the time of the study. CONCLUSIONS: There was significantly poor optometric and ophthalmic contact in patients who had VI and had fallen and sustained hip fracture. A proportion of the VI (66%) was due to uncorrected refractive error and untreated cataract. Public health providers should be made aware of the fact that current optometric and ophthalmic care pathways are not accessed by this group of elderly patients with VI and at risk of falling.

Accidental Falls↗

PubMed2005

Effects of magnesium on atrial fibrillation after cardiac surgery: a meta-analysis.

OBJECTIVES: To assess the efficacy of the administration of magnesium as a method for the prevention of postoperative atrial fibrillation (AF) and to evaluate its influence on hospital length of stay (LOS) and mortality. METHODS: Literature search and meta-analysis of the randomised control studies published since 1966. RESULTS: 20 randomised trials were identified, enrolling a total of 2490 patients. Study sample size varied between 20 and 400 patients. Magnesium administration decreased the proportion of patients developing postoperative AF from 28% in the control group to 18% in the treatment group (odds ratio 0.54, 95% confidence interval (CI) 0.38 to 0.75). Data on LOS were available from seven trials (1227 patients). Magnesium did not significantly affect LOS (weighted mean difference -0.07 days of stay, 95% CI -0.66 to 0.53). The overall mortality was low (0.7%) and was not affected by magnesium administration (odds ratio 1.22, 95% CI 0.39 to 3.77). CONCLUSION: Magnesium administration is an effective prophylactic measure for the prevention of postoperative AF. It does not significantly alter LOS or in-hospital mortality.

Anti-Arrhythmia Agents↗

PubMed2005

Perioperative monitoring of flow and patency in native and grafted internal mammary arteries using a combined MR protocol.

The objective of this study was to evaluate graft flow (f) and patency (p) in patients with internal mammary artery (f,p) and venous (p only) grafts using a combined MR protocol with phase-contrast technique and MR angiography. 42 patients with 42 left internal mammary artery (LIMA) and 63 venous grafts were examined pre and 6 months post coronary artery bypass graft (CABG) surgery. Phase-contrast flow measurements were applied to the IMA. Post-operatively, a contrast enhanced MR angiogram was performed to assess bypass patency. LIMA/venous grafts were occluded in 3/42 and 13/63, respectively. Flow in LIMA decreased from 19.4+/-10.4 ml min(-1) m(-2) pre-operatively to 13.4+/-9.7 ml min(-1) m(-2) post-operatively (p<0.002). In contrast, flow in the native right IMA increased from 17.6+/-8.7 ml min(-1) m(-2) pre-operatively to 24.8+/-9.0 ml min(-1) m(-2) post-operatively (p<0.001). MRI allows a combined assessment of bypass patency and flow. This study protocol may be applicable to perioperative follow-up studies in patients after CABG surgery.

Aged↗

PubMed2005

Effects of adjuvants on safety and efficacy of an Escherichia coli J5 bacterin.

The effects of using a water-soluble adjuvant or an emulsified oil-based adjuvant on the safety, antibody titer, and clinical responses of an Escherichia coli J5 bacterin were tested in an experimental infection trial. Fifty-one cows were assigned to 17 blocks of 3. Two cows within each block of 3 were vaccinated with a commercially prepared E. coli J5 bacterin containing either a water-soluble adjuvant or the same bacterin preparation emulsified in oil. One cow in each block was an unvaccinated control. Cows were immunized at drying off and 42 d later. The right or left front mammary quarter of each experimental cow was challenged by intramammary infusion of E. coli 727 between 14 and 35 DIM. Areas of inflammation at the primary injection site were greater 1, 2, and 3 d following primary vaccination for bacterin containing oil-in-water adjuvant compared with bacterin containing water-soluble adjuvant. Whey anti-E. coli J5 IgG titers were higher at calving for cows vaccinated with bacterin containing oil-in-water adjuvant than for cows either vaccinated with bacterin containing water-soluble adjuvant or unvaccinated controls. Serum x-E. coli J5 IgG titers were higher at calving for vaccinated cows than for unvaccinated controls. Peak bacterial counts in milk from challenged quarters were greater for unvaccinated controls than for cows vaccinated with bacterin containing water-in-oil adjuvant. Bacterial counts in milk from challenged quarters and clinical score both were greater in unvaccinated controls than cows vaccinated with bacterin containing water-in-oil adjuvant between 12 and 24 h postchallenge. Clinical responses were similar between unvaccinated controls and cows vaccinated with bacterin containing water-soluble adjuvant.

Adjuvants, Immunologic↗

PubMed2004

Unexpected complexity in the haplotypes of commonly used inbred strains of laboratory mice.

Investigation of sequence variation in common inbred mouse strains has revealed a segmented pattern in which regions of high and low variant density are intermixed. Furthermore, it has been suggested that allelic strain distribution patterns also occur in well defined blocks and consequently could be used to map quantitative trait loci (QTL) in comparisons between inbred strains. We report a detailed analysis of polymorphism distribution in multiple inbred mouse strains over a 4.8-megabase region containing a QTL influencing anxiety. Our analysis indicates that it is only partly true that the genomes of inbred strains exist as a patchwork of segments of sequence identity and difference. We show that the definition of haplotype blocks is not robust and that methods for QTL mapping may fail if they assume a simple block-like structure.

Alleles↗

PubMed2004

Comparison of first-line antiretroviral therapy with regimens including nevirapine, efavirenz, or both drugs, plus stavudine and lamivudine: a randomised open-label trial, the 2NN Study.

BACKGROUND: The 2NN Study was a randomised comparison of the non-nucleoside reverse-transcriptase inhibitors (NNRTI) nevirapine and efavirenz. METHODS: In this multicentre, open-label, randomised trial, 1216 antiretroviral-therapy-naive patients were assigned nevirapine 400 mg once daily, nevirapine 200 mg twice daily, efavirenz 600 mg once daily, or nevirapine (400 mg) and efavirenz (800 mg) once daily, plus stavudine and lamivudine, for 48 weeks. The primary endpoint was the proportion of patients with treatment failure (less than 1 log(10) decline in plasma HIV-1 RNA in the first 12 weeks or two consecutive measurements of more than 50 copies per mL from week 24 onwards, disease progression [new Centers for Disease Control and Prevention grade C event or death], or change of allocated treatment). Analyses were by intention to treat. FINDINGS: Treatment failure occurred in 96 (43.6%) of 220 patients assigned nevirapine once daily, 169 (43.7%) of 387 assigned nevirapine twice daily, 151 (37.8%) of 400 assigned efavirenz, and 111 (53.1%) of 209 assigned nevirapine plus efavirenz. The difference between nevirapine twice daily and efavirenz was 5.9% (95% CI -0.9 to 12.8). There were no significant differences among the study groups in the proportions with plasma HIV-1 RNA concentrations below 50 copies per mL at week 48 (p=0.193) or the increases in CD4-positive cells (p=0.800). Nevirapine plus efavirenz was associated with the highest frequency of clinical adverse events, and nevirapine once daily with significantly more hepatobiliary laboratory toxicities than efavirenz. Of 25 observed deaths, two were attributed to nevirapine. INTERPRETATION: Antiretroviral therapy with nevirapine or efavirenz showed similar efficacy, so triple-drug regimens with either NNRTI are valid for first-line treatment. There are, however, differences in safety profiles. Combination of nevirapine and efavirenz did not improve efficacy but caused more adverse events.

Adult↗

PubMed2004

Cluster growth in two- and three-dimensional granular gases.

Dissipation in granular media leads to interesting phenomena such as cluster formation and crystallization in nonequilibrium dynamical states. The freely cooling system is examined concerning the energy decay and the cluster evolution in time, both in two and three dimensions. We also suggest an interpretation of the three-dimensional cluster growth in terms of percolation theory, but this point deserves further study.

Journal Article↗

PubMed2004

A non-inflatable anti-shock garment for obstetric hemorrhage.

OBJECTIVES: Maternal death from hemorrhage in low resource settings is frequently due to long delays in transportation to referral centers and/or in obtaining blood and surgical interventions. This case series was designed to demonstrate the feasibility, efficacy and safety of the non-inflatable anti-shock garment (NI-ASG) for resuscitation and hemostasis in the initial management of obstetric hemorrhage and shock. METHODS: Fourteen cases of obstetric hemorrhage and hypovolemic shock at Memorial Christian Hospital, Sialkot, Pakistan were managed with a specific clinical protocol based on using NI-ASG as the primary intervention. RESULTS: The NI-ASG was used to resuscitate and stabilize women with hypovolemic shock from 18 to 57 h. Thirteen patients survived without evidence of morbidity, but one had prolonged shock followed by multiple organ failure and death. CONCLUSIONS: This study confirmed that the NI-ASG quickly restored the vital signs of most women in severe hemorrhagic shock and stabilized them while awaiting blood transfusion.

Adult↗

PubMed2004

A preliminary study identifying risk factors in drop-out from a prison therapeutic community.

Three different groups of therapy leavers and current residents (total n = 80) from Dovegate Prison's Therapeutic Community (TC) were compared on various demographic, criminogenic and psychometric attributes. Statistically significant findings distinguished the leaver groups from current residents and differentiated between type of leavers. Those leavers judged as unsuitable for therapy were characterised by high scores of Psychopathy, Neuroticism, Criminality, Addiction, Venturesomeness, and Avoidant and Schizoid Personality Disorders. Those leavers who had elected to leave the TC were more likely to have a sexual index offence, significant scores on the Multiphasic Sex Inventory, and Paranoid and Depressive Personality Disorders. Logistic Regression analysis confirmed that particular personality disorders were predictive of therapy leaver group membership. Paranoid Personality Disorder was identified as a predictor of all types of drop-out. These findings provide a psychological profile of the different types of residents who have left a prison therapeutic community and can be used to support and inform selection and assessment practices.

Adult↗

PubMed2004

Linkage disequilibrium maps constructed with common SNPs are useful for first-pass disease association screens.

To develop an efficient strategy for mapping genetic factors associated with common diseases, we constructed linkage disequilibrium (LD) maps of human chromosomes 5, 7, 17, and X. These maps consist of common single nucleotide polymorphisms at an average intermarker distance of 100 kb. The genotype data from these markers in a panel of American samples of European descent were analyzed to produce blocks of markers in strong pair-wise LD. Power calculations were used to guide block definitions and predicted that high-level LD maps would be useful in initial genome scans for susceptibility alleles in case-control association studies of complex diseases. As anticipated, LD blocks on the X chromosome were larger and covered more of the chromosome than those found on the autosomes.

Black or African American↗

PubMed2004

[TrueFISP MR imaging to determine the influence of hemodialysis on the myocardial functional parameters in patients with terminal renal insufficiency].

PURPOSE: To assess the characteristic signs of uremic cardiomyopathy in patients with chronic renal failure (CRF) in comparison with healthy volunteers and to determine changes of left ventricular (LV) functional parameters in patients undergoing hemo-dialysis (HD). METHODS AND MATERIALS: Using a 1.5 T Magnetom Sonata system (Siemens, Erlangen), cardiac MR imaging was performed on 26 patients (20 men, 6 women, mean age 54.7 years) and 14 volunteers (8 men, 6 women, mean age 27.7 years). Single-slice true FISP sequences (TR 3.2 ms, TE 1.6 ms, flip angel 58 degrees, matrix 256 x 208, slice thickness 5 mm) were used to obtain contiguous short axis slices covering the whole left ventricle. Patients were examined before and immediately after HD. Cardiodynamic parameters [end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), myocardial mass (MM), cardiac output (CO)] were calculated using the modified Simpson's rule (Argus Software, Siemens). Patient data were compared to reference values taken from healthy volunteers. RESULTS: As a consequence of HD, significant differences (p < 0.01) were observed for EDV (150 + 47 ml/114 + 49 ml), ESV (71 + 46 ml/60 + 56 ml), SV (79 + 25 ml/57 + 27 ml) and CO (3.6 + 1.0 l/min*m (2)/2.6 + 1.1 l/min*m (2)). Although EF (56 + 15 %/53 + 18 %) was decreased after HD, values did not differ significantly (p > 0.05). MM (148 + 47 g/148 + 52 g) and myocardial mass index (80.7 +/- 27.4 g/m (2)/80.1 +/- 9.1 g/m (2)) did not change before and after HD. In all patients, signs of LV-hypertrophy (LVH) and increased CO were diagnosed compared to reference values. In 8 of 26 patients, additional pathology, such as valvular dysfunction or global cardiac insufficiency, was detected. CONCLUSION: Cardiac MRI is an accurate tool to identify uremic cardiomyopathy in patients with chronic renal failure undergoing HD. LV functional parameters could be monitored reliably.

Adult↗

PubMed2004

[Clinical value of mammography, ultrasound and MR imaging during the first year after breast conserving therapy of breast cancer].

PURPOSE: To compare the accuracy of lesion detection and characterization and to determine the agreement of observers, methods and timing of mammography (MX), ultrasound (US) and MR imaging (MRI) during the first year after breast conserving therapy. MATERIALS AND METHODS: The study included 20 patients diagnosed with breast cancer of stages equal or inferior to T2 N1bi M0 after breast conserving therapy and subsequent radiotherapy. Patients with any history of breast diseases in the affected or contralateral breast were excluded. Patients were examined before and at 3, 6 and 12 months after adjuvant radiotherapy with MX, US and dynamic MR mammography. Additional US and MRI were performed 3 months after radiotherapy. All 220 examinations were retrospectively read in a randomized order by two independent readers, blinded for the results of the other examinations. The outcome after 2.5 years of follow-up was used as gold standard. Histological examination was available in one case. Lesion detection and specificity were assessed including kappa values for different reliabilities between observers, timing and methods. The kappa values were used to characterize the degree of agreement as follows: > 0.8 very good; 0.6 - 0.8 good; 0.4 - 0.6 fair; 0.2 - 0.4 minimal; and < 0.2 negligible. RESULTS: Based on the interpretation of all available findings (clinical examination, MX, US, MRT and histology in one case), 20 patients observed for a mean period of 2.5 years had no evidence of intramammary recurrence. Therefore the sensitivity of the various methods could not be assessed. The reading of certainly no lesion was given by MRI in 43 %, by MX in 30 % and by US in 5 % of all examinations (p < 0.05). True negative findings were observed by MRI in 94.4 %, by MX in 90.4 % and by US in 82.5 %. Reliability between observers, timing and imaging methods was 0.496, 0.411, and 0.215 for lesion detection and 0.303, 0.282, and 0.030 for lesion characterization. CONCLUSION: Within the first year after breast conserving therapy, MRI was the most confident method for the exclusion of lesions and presented the highest true negative rate. The assessment of dignity of a particular lesion was difficult by all imaging methods, reflected by the weak agreement between observers, methods and timing. The difference between times of readings were marginal in the first year after therapy. Agreement between the different diagnostics methods was minimal to negligible.

Adult↗

PubMed2004

[Clinical implication of parameter-optimized 3D-FISP MR angiography (MRA) in children with aortic coarctation: comparison with catheter angiography].

PURPOSE: To implement parameter-optimized 3D-FISP MR angiography (MRA) with interleaved double-slab excitation and to compare the result with catheter angiography in children with aortic coarctation. MATERIALS AND METHODS: Eighteen children aged 2 - 15 years (mean 9.1 years) underwent MR imaging on a 1.5T body scanner (Magnetom Vision, Siemens, Germany). All patients had undergone correlative catheter angiography. T1-weighted turbo spin echo (TSE) images (TR 600 ms, TE 17 ms, flip 160 degrees, slice thickness 2 - 4 mm) were obtained in axial and parasagittal orientation, followed by an optimized 3D-FISP MR angiography in a sagittal plane (TR 12.5 ms, TE 5.5 ms, flip 22 degrees, matrix 256 x 256, slice thickness 1.25 mm). All children were sedated but on spontaneous breathing. Image quality was graded by two experienced reviewers using a 4-point scoring system. Source images and reformatted maximum intensity projections (MIP) were analyzed for blood-tissue contrast as well as size and focal stenoses of the aortic arch. RESULTS: Aortic coarctation was found in 13 of 18 patients, using the 3D-FISP MRA. A high correlation value (r = 0.96) was found compared to catheter angiography. Image quality was high in 94 % with well defined blood-tissue contrast in all cases. The sensitivity to flow and breathing motion was low. Examination time was about 15 minutes depending on volume of interest and heart rate. Diagnostic accuracy has shown improvement using a combined analysis of source and MIP images. The mentioned technique has provided an excellent display of thoracic vasculature. CONCLUSION: MR imaging represents an excellent tool for non-invasive examination of the cardiovascular system of children. The 3D-MRA allows the recording of a large 3D data set without the use of contrast agent and within an adequate measurement period, particularly in small infants unable to hold their breath. In addition, hemodynamic significance of aortic coarctation, the existence of collateral vessels and other congenital heart diseases can be described reliably by using this technique.

Adolescent↗