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Biomedical subjects

A Lembcke

Publications and source records attributed to A Lembcke.

At least 19 recordsLinked to original sources
PubMed2006

Uterine artery embolization for symptomatic fibroids: short-term versus mid-term changes in disease-specific symptoms, quality of life and magnetic resonance imaging results.

BACKGROUND: Prospective study to evaluate changes in symptom severity, health-related quality of life (HRQOL) and uterine and leiomyoma volume after uterine artery embolization (UAE). METHODS: Eighty-two women completed a validated uterine fibroid symptom and quality of life (UFS-QOL) questionnaire and underwent magnetic resonance imaging (MRI) before and 3-20 months after UAE. Primary outcome measures were changes in symptom severity and QOL at short-term follow-up [median 5 (range 3-7) months] and mid-term follow-up [median 14 (8-20) months]. Secondary outcome measures included the frequency of additional procedures to control persistent symptoms and changes in dominant fibroid volume (DFV) and uterine volume (UV). RESULTS: Of 82 patients, 71 (86.6%) patients completed follow-up, 7 (8.5%) patients had a second procedure and 4 (4.9%) were lost to follow-up. Symptom severity scores decreased from a median of 43.75 to 21.88 (P < 0.001) in the short-term follow-up group and from a median of 43.75 to 9.38 (P < 0.001) in the mid-term follow-up group. QOL scores increased from a median of 56.90 to 87.93 (P < 0.001) and 66.81 to 96.12 (P < 0.001), respectively. During short-term follow-up, median UV decreased by 27% (95% CI 20.25-33.81, P < 0.001) and median DFV by 62% (95% CI 47.81-71.55, P < 0.001), whereas UV decreased by 36% (95% CI 23.34-55.02, P < 0.001) and DFV by 66% (95% CI 54.28-71.92, P < 0.001) for the mid-term follow-up group. A decrease in UV correlated with change in symptom severity (P < 0.005). CONCLUSIONS: Women report significant improvements in fibroid-specific symptoms and QOL at short- and mid-term follow-ups after UAE.

Adult↗
PubMed2006

[Whole-body MR angiography: comparison of two protocols for contrast media injection].

PURPOSE: To compare two injection strategies for contrast media injection in whole-body MR angiography quantitatively and qualitatively with regard to contrast and image quality. MATERIAL AND METHODS: 40 patients were examined at 1.5 Tesla using either a single injection protocol or a double injection protocol with two separate bolus injections. Vessel regions I (supraaortic/thoracic), II (abdominal/pelvic), III (upper legs) and IV (lower legs) were examined in the following order: single injection: I, II, III, IV, double injection: I and IV after the first injection, II and III after the second bolus injection. Quantitative evaluation: SI measurements were carried out in 2 arteries per region. Contrast values were calculated. Qualitative evaluation: Evaluation of regions I-IV regarding vessel contrast, venous overlay and image quality on a five-point scale by two reviewers in consensus. The Mann-Whitney-U test was used to test the differences for significance. RESULTS: Quantitative evaluation: Using the double injection protocol, significantly higher contrast values in regions I and II and significantly lower contrast values in the subregions IIIa (upper part of III) and IVb (lower part of IV) were obtained (p < 0.05). The mean contrast values in subregions IIIb (lower part of III) and IVa (upper part of IV) were lower using the double injection protocol, but not significantly. Qualitative evaluation: Using the double injection protocol, region II was rated significantly higher (mean ratings: 3.55, 3.45 and 3.5 versus 2.7, 2.5 and 2.55; p < 0.05) and region III significantly lower (mean ratings: 3.1, 2, 2.5 versus 3.9, 3.1 and 3.55; p < 0.05) for all three examined criteria. When using the double injection protocol, ratings were significantly lower in region IV regarding vessel contrast and image quality (mean ratings: 2.4 and 2.15 versus 3.45 and 3.15; p < 0.05). The ratings regarding venous overlay in region IV showed no significant differences (mean ratings: 2.15 versus 2.75; p > 0.05). CONCLUSION: Due to the better results in the supraaortic/thoracic and abdominal/pelvic regions, the double injection protocol is preferred. However, both protocols require further improvement.

Adult↗
PubMed2006

[A new method for standardized diagnosis following renal transplantation. Ultrasound with contrast enhancement].

Ultrasound (US) imaging is an important diagnostic tool following renal transplantation. Unfortunately, due to the heterogeneity of the recipients and their multimorbidity, imaging procedures in the early phase after kidney transplantation are difficult and of limited use. We performed a study to evaluate the use of a contrast enhancer for US examination as a standardized method in the follow-up of kidney transplant recipients.The study included 40 recipients: 32 were examined on the 5th to 7th day following transplantation and 8 patients at the time when clinically suspicious findings occurred (acute rejection, tumor, acute tubular necrosis). Following the intravenous application of the contrast medium, pictures were taken during the arterial and parenchymatous phase and compared with conventional B-mode and power Doppler pictures of the same visual plane. Three examiners assessed different parameters of the transplant organ (max. vascularized area, suspected hematomas, tumors, rejection, acute tubular necrosis). Findings were confirmed by histological results of a biopsy if rejection, tumor, or acute tubular necrosis were suspected. Application of ultrasound contrast medium significantly increased visualization of the vascularized kidney area. Also, US findings in the follow-up after acute rejection therapy corresponded with the clinical course; 19 hematomas could be detected with contrast medium compared to only 9 without. With contrast medium a perfusion deficit was detectable in three patients compared to one patient with power Doppler US. Also, US contrast medium helped to detect tumor vascularization in two patients in whom conventional sonography suspected no abnormality. Ultrasound contrast medium enhancement is a reproducible, reliable, and easy to apply method which is superior to conventional sonography in the follow-up after kidney transplantation. This method is also helpful to detect and control acute rejections and to better visualize hematomas, deficits of perfusion, and tumors.

Adolescent↗
PubMed2005

[Surgery for congestive heart failure--the role of computed tomography in the pre- and postoperative diagnostic evaluation].

The treatment of advanced, drug resistant congestive heart failure gains in importance in the field of cardiac surgery. Cardiac imaging for preoperative assessment and follow-up focuses on the determination of ventricular volumes and function as well as on the detection of postoperative complications. Computed tomography (CT) is highly accurate irrespective of the individual patient's anatomic situation, has a low examiner dependence and short examination time, does not require an arterial vascular access and can be performed in patients with metal implants. CT is the modality of choice in the follow-up of heart transplants to detect extracardiac and cardiac complications including coronary calcifications as an early sign of transplant vasculopathy. In addition, CT visualizes the elements of mechanical assist devices and can identify their possible local cardiac and mediastinal complications. CT can detect fibrolipomatous involution of the mobilized muscle flap in dynamic cardiomyoplasty and can depict fibrous reactions along the epicardial mesh implant in passive cardiac containment. Further indications include assessment of typical local postoperative complications, such as intrathoracic infection and mediastinal bleeding, intracardiac thrombus formation or pericardial effusion. CT is routinely used for evaluating bypass patency but is limited in assessing associated valve defects since it does not visualize flow.

Cardiovascular Surgical Procedures↗
PubMed2004

[Technical success rate, peri-interventional complications and radiation exposure of the transarterial embolization for leiomyomas of the uterus].

PURPOSE: To analyze the technical success rate, incidence and type of peri-interventional complications, and radiation exposure of uterine artery embolization (UAE) in symptomatic leiomyomas of the uterus. MATERIALS AND METHODS: This prospective study includes 75 patients consecutively treated with UAE from October 2000 through August 2002, with all interventions performed by the same radiologist. Technical success rate, interventional material, and incidence and type of peri-interventional complications (length of hospitalization) were recorded and categorized according to the definitions of the Society of Interventional Radiology (SIR). Fluoroscopy time (FT), dose-area product (DAP), and effective dose (ED) were determined for each intervention and the influence of the radiologist's experience on the radiation exposure analyzed. RESULTS: UAE was technically successful in 97.3 % of the cases. Peri-interventional complications occurred in 14.7 %. Four complications (5.3 %) were classified as major class C according to the SIR (post-embolization syndrome requiring prolonged drug treatment and hospitalization [n = 3] perforation of the uterine artery [n = 1]). None of the complications led to discontinuation of the intervention, subsequent surgical intervention, or permanent sequelae. FT decreased significantly (p < 0.05) until the 35th intervention. The median FT decreased from 18.8 min (13.4 - 28 min [25th to 75th percentile]) to 11.8 min (9.7 - 13.3 min [25th to 75th percentile]). The DAP decreased by 25.3 % to a median of 8.547 (6.527 - 11.590 cGy*cm (2) [25th to 75th percentile]). The median ED was 31.5 mSv from the 36th intervention onward. CONCLUSION: UAE has a high technical success rate with a low rate of peri-interventional complications. The study showed a statistically significant learning effect with a decrease in radiation exposure for the first 35 interventions. The effective dose of UAE is comparable to that of 1 to 2 small bowel enema.

Adult↗
PubMed2004

Multislice CT coronary angiography: evaluation of an automatic vessel detection tool.

PURPOSE: To investigate the potential of a new detection tool for multislice CT (MSCT) coronary angiography with automatic display of curved multiplanar reformations and orthogonal cross-sections. MATERIALS AND METHODS: Thirty-five patients were consecutively enrolled in a prospective intention-to-diagnose study and examined using a MSCT scanner with 16 x 0.5 mm detector collimation and 400 ms gantry rotation time (Aquilion, Toshiba). A multisegment algorithm using up to four segments was applied for ECG-gated reconstruction. Automatic and manual detection of coronary arteries was conducted using the coronary artery CT protocol of a workstation (Vitrea 2, Version 3.3, Vital Images) to detect significant stenoses (> or = 50 %) in all segments of > or = 1.5 mm in diameter. Each detection tool was used by one reader who was blinded to the results of the other detection method and the results of conventional coronary angiography. RESULTS: The overall sensitivity, specificity, nondiagnostic rate, and accuracy of the automatic and manual approach were 90 vs. 94 %, 89 vs. 84 %, 6 vs. 6 %, and 89 vs. 88 %, respectively (p = n. s.). The vessel length detected with the automatic and manual approach were highly correlated for the left main/left anterior descending (143 +/- 30 vs. 146 +/- 24 mm, r = 0.923, p < 0.001), left circumflex (94 +/- 35 vs. 93 +/- 33 mm, r = 0.945, p < 0.001), and right coronary artery (145 +/- 36 vs. 144 +/- 37 mm, r = 0.925, p < 0.001). The time required to create reformations along the coronary arteries was significantly shorter with the automatic tool compared to the manual approach (203 +/- 77 vs. 391 +/- 104 sec, p < 0.005). In 90 % of the coronary branches automatic detection required less time than the manual approach. CONCLUSION: Automatic coronary vessel detection is feasible and reduces the time required to create reformations by a factor of approximately two without deteriorating the diagnostic accuracy.

Aged↗
PubMed2004

Early postoperative ultrasound of kidney transplants: evaluation of contrast medium dynamics using time-intensity curves.

OBJECTIVE: To evaluate kidney recipients in the early posttransplant phase by semiquantitative analysis of the arterial arrival of ultrasound (US) contrast medium using time-intensity curves. PATIENTS AND METHODS: Twenty-two kidney recipients underwent US examination after intravenous bolus administration of 2.4 ml of US contrast medium (SonoVue, Bracco Altana) 5 to 7 days after transplantation. The examinations were performed with the Aplio US system (Toshiba) and a 3.5-MHz wideband transducer using contrast harmonic imaging at a low mechanical index of 0.1. Arterial arrival was documented digitally over 60 sec (image repetition rate: 10 images per sec) for subsequent evaluation of contrast medium kinetics in the main renal artery, interlobar artery, subcapsular area, and renal vein using the system's integrated time-intensity curve (TIC) software. The increase, decrease, and percentage enhancement factor were calculated from the curves. Four patients were excluded from analysis because of perirenal hematoma (n = 3) or a polar perfusion loss demonstrated by power Doppler (n = 1). RESULTS: Twelve of the remaining 18 patients assigned to the nonrejection group showed an uneventful clinical course. These had uniform TICs with an early and steep increase of similar magnitude in the main renal artery (11.7 +/- 4.5 intensity units/sec), interlobar artery (8.7 +/- 4.6 intensity units/sec), and subcapsular area (8.3 +/- 3.7 intensity units/sec) followed by a washout and subsequent plateau phase. Six patients showed histologically proven acute rejection on day 5 or 6 after transplantation (rejection group). This group had a delayed (time to peak in the subcapsular area: 32.9 +/- 8.3 sec in the rejection group versus 20.9 +/- 4.7 sec in the nonrejection group, p < 0.05) and smaller subcapsular percentage increase (41.2 +/- 21.9 % versus 114.4 +/- 59.8 %, p < 0.05). In the rejection group the subcapsular area (3.8 +/- 2.3 intensity units/sec) showed a less pronounced increase than the main renal artery (7.9 +/- 5.9 intensity units/sec) and interlobar artery (8.7 +/- 3.8 intensity units/sec). The RI in the rejection group was in the normal range at the time of contrast-enhanced US (day 5: 0.78 +/- 0.06) and increased to abnormal levels in the further course (day 7: 0.94 +/- 0.09). CONCLUSIONS: Quantitative determination of arterial arrival of an US contrast medium in the early phase after kidney transplantation is possible. This new US procedure might identify acute rejection earlier than conventional techniques.

Adult↗
PubMed2004

[Value of electron beam tomography (EBT)].

Electron beam tomography (EBT) has been scientifically evaluated to a much lesser degree for non-cardiac indications than for cardiac purposes. Therefore, four groups of investigators in Berlin (2), Mannheim and Munchen, which were supported by the Deutsche Forschungsgemeinschaft (DFG), included applications outside the heart in their evaluation of EBT technology. EBT has proven useful to look for pulmonary embolism and to assess other vessels (aorta, aortic branches, and intracranial arteries). Imaging of the lung parenchyma benefits from its intrinsic high contrast and from the fast data acquisition of EBT. Limited photon efficiency, higher radiation exposure, increased noise levels and other artifacts, however, markedly reduce the value of EBT for imaging of low contrast objects compared to conventional spiral CT and multislice CT (MSCT), compromising, in particular, the morphologic depiction of parenchymal abdominal organs and the brain. Consequently, scientific studies to further evaluate EBT for scanning of the brain and parenchymal abdominal organs were not pursued. Radiation exposure for non-cardiac EBT studies is up to three times higher than that for respective spiral CT studies, and in children EBT can only be advocated in select cases. Radiation exposure for the various prospectively triggered cardiac examination protocols of EBT is lower than that for conventional coronary angiography. Radiation exposure in cardiac multislice CT exceeds severalfold that of EBT, but the dose efficiency of EBT and MSCT are similar due to higher spatial resolution and less image noise of MSCT. In addition, modifications of MSCT (ECG pulsing) can further reduce radiation exposure to the level of EBT. Technical improvements of the EBT successor scanner "e-Speed" enable faster data acquisition at higher spatial resolution. Within comparative studies, the "e-Speed" will have to prove its value and competitiveness, particularly in comparison with multislice CT. After profound scientific assessment in a multicenter evaluation supported by the Deutsche Forschungsgemeinschaft (DFG) and regardless of the specific suitability of electron beam tomography for various cardiac and some non-cardiac indications, the investigators unanimously find the electron beam tomograph Evolution C150 XP not suitable as a whole body CT scanner.

Age Factors↗
PubMed2004

[Diagnostic value of electron-beam computed tomography (EBT). I. Cardiac applications].

Electron beam tomography (EBT) directly competes with other non-invasive imaging modalities, such as multislice computed tomography, magnetic resonance imaging, and echocardiography, in the diagnostic assessment of cardiac diseases. EBT is the gold standard for the detection and quantification of coronary calcium as a preclinical sign of coronary artery disease (CAD). Its standardized examination protocols and the broad experience with this method favor EBT. First results with multislice CT indicate that this new technology may be equivalent to EBT for coronary calcium studies. The principal value of CT-based coronary calcium measurements continues to be an issue of controversy amongst radiologists and cardiologists due to lack of prospective randomized trials. Coronary angiography with EBT is characterized by a high negative predictive value and, in addition, may be indicated in some patients with manifest CAD. It remains to be shown whether coronary angiography with multislice CT is reliable and accurate enough to be introduced into the routine work-up, to replace some of the many strictly diagnostic coronary catheterizations in Germany and elsewhere. Assessment of coronary stent patency with EBT is associated with several problems and in our opinion cannot be advocated as a routine procedure. EBT may be recommended for the evaluation of coronary bypasses to look for bypass occlusions and significant stenoses, which, however, can be equally well achieved with multislice CT. Quantification of myocardial perfusion with EBT could not replace MRI or other modalities in this field. EBT has proven to be accurate, reliable and in some instances equivalent to MRI, which is the gold standard for the quantitative and qualitative evaluation of cardiac function. Some disadvantages, not the least of which is the limited distribution of electron beam scanners, favor MRI for functional assessment of the heart.

Adult↗
PubMed2004

Assessment of left ventricular volumes and function: intraindividual comparison of multi-slice spiral CT and electron beam CT in an animal model.

PURPOSE: To evaluate multi-slice spiral computed tomography (MSCT) for measurements of left ventricular volumes, ejection fraction (EF), and myocardial mass in comparison with electron beam CT (EBCT) as a reference method. MATERIAL AND METHODS: Six minipigs underwent both standardized contrast-enhanced MSCT (effective acquisition time per cardiac cycle 125.7+/-30.1 ms, reconstructed slice thickness 8 mm) and EBCT (acquisition time 50 ms, collimated slice thickness 8 mm). The contrast-to-noise ratio of the left ventricle was measured in each animal, and the contour sharpness of the myocardium was analyzed. Volumes (EDV, ESV, SV) ejection fraction (EF), and muscle mass were calculated by MSCT and by EBCT using the slice summation method. RESULTS: MSCT had a higher contrast-to-noise ratio and delineated the myocardial contours more sharply than EBCT. There was a close linear correlation between both modalities for all parameters (EDV: rP=0.88, ESV: rP=0.91, SV: rP=0.85, EF: rP=0.93; mass: rP=0.90; P<0.05 each). MSCT slightly overestimated ESV and slightly underestimated SV and EF compared with EBCT (P<0.05 each). CONCLUSIONS: Image quality in MSCT is superior to that of EBCT. Functional parameters correlate well between both modalities, but the accuracy of MSCT is limited by its lower temporal resolution.

Animals↗
PubMed2003

[Imaging of the coronary arteries by means of multislice helical CT: optimization of image quality with multisegmental reconstruction and variable gantry rotation time].

PURPOSE: To evaluate the potential of multisegmental reconstruction and variable gantry rotation time for reducing motion-induced artifacts in coronary artery imaging by multislice helical CT. MATERIALS AND METHODS: The data sets of 20 patients (8 with HR < 60 bpm, 12 with HR > 60 bpm) were analyzed. The patients underwent multislice helical CT (Aquilion 8, Toshiba, Otawara, Japan) using the following parameters: 0.5 mm slice thickness, 250 mA, 120 kV, pitch of 0.25 and variable gantry rotation times of 400, 500, or 600 msec. Images were generated by halfscan and multisegmental reconstruction. In 9 coronary segments of each patient, the presence and severity of motion artifacts were assessed and graded on a scale between 5 (no artifacts) and 1 (heaviest artifacts). RESULTS: Diagnostically relevant motion artifacts were rare at low heart rates (< 60 bpm) for both types of image reconstruction (4 % of all segments). Higher heart rates (> 60 bpm) were associated with an increase in motion artifacts on halfscan reconstructions (33% of all segments, p < 0.05) but not on multisegmental reconstructions (4% of all segments). At low heart rates mean image quality did not differ between multisegmental and halfscan reconstruction (4.28 +/- 0.37 vs. 4.22 +/- 0.41; p > 0.05), whereas at higher heart rates image quality was better for multisegmental reconstruction than for halfscan reconstruction (4.23 +/- 0.47 vs. 3.11 +/- 0.63; p < 0.05). CONCLUSION: Multisegmental reconstruction with variable gantry rotation times suppresses motion artifacts and thus improves assessment of the coronary arteries in patients with higher heart rates.

Artifacts↗
PubMed2003

[Evaluation of passive cardiomyoplasty using left- and right-ventricular volume measurements by EBCT and MRI in patients with chronic congestive heart failure].

PURPOSE: To evaluate the efficacy of passive cardiomyoplasty with the determination of biventricular volumes, global systolic function as well as left-ventricular muscle mass. MATERIALS AND METHODS: In 19 patients with congestive heart failure of idiopathic or ischemic origin, a polyester mesh-graft was implanted around both ventricles for stabilization and functional support. Before and three months after surgery, 15 patients underwent EBCT and 4 patients with impaired renal function underwent MRI, for the evaluation of the volume and ejection fraction of both ventricles. RESULTS: EBCT demonstrated a decrease from 385 to 310 ml in LV-EDV, from 312 to 242 ml in LV-ESV, from 209 to 160 ml in RV-EDV and from 149 to 87 ml in RV-ESV, and an increase from 20 to 26% in LV-EF and from 37 to 50% in RV-EF as well as a reduction of LV-MM from 300 to 274 g (p < 0.05 each). Similar results were obtained by MRI. CONCLUSION: Following passive cardiomyoplasty, EBCT and MRI revealed an improvement of the global systolic function as well as a reduction of biventricular volumes and left-ventricular muscle mass.

Adult↗
PubMed2003

[Spatial and temporal resolution with 16-slice computed tomography for cardiac imaging].

The use of the CT scanner for cardiac imaging is mainly influenced by the spatial and temporal resolution that can be achieved with the applied technologies and procedures. The data acquisition with 16 x 0.5 mm scan slice thickness and a special multisegment image reconstruction procedure are a new combination for accurate imaging of the cardiac morphology. A 0.5 mm slice thickness and an overlapping pitch < 0.35 generate an isotropic image voxel of 0.35 x 0.35 x 0.35 mm. The object size of a coronary artery with a diameter of 2.5 mm amounts to a relative spatial blurring factor K (d) of approximately 15 %. The segment reconstruction with 4 segments from 4 consecutive cardiac cycles requires the optimum acquisition time of 50 ms for one frame. The relative exposure factor K (t) with reference to the R-R interval is an appropriate measure to validate the influence of coronary artery movement on the image quality at different heart rates. This relative exposure varies between 10 % and 20 % for a heart rate of 40 to 140 beats per minutes (bpm) and its mean is approximated by a linear trend function with K (t) = 14 %. A constant value in this linear trend function means a constant "blurring" of the imaged coronary arteries, independent of the actual heart rate. Thus, computed tomographic examinations can be carried out for heart rates between 40 and 140 bpm without using beta-blocking medication. Case studies of the 3D reconstruction and curved reformatting of coronary arteries with stents and calcifications show the achievable image quality at different heart rates.

Algorithms↗
PubMed2003

Visualization of the pulmonary valve using cine MR imaging.

PURPOSE: To evaluate the capability of bright-blood cine MR to directly visualize the leaflets of the valve replacement in pulmonary position following Ross operation. MATERIAL AND METHODS: Long and short axis views of the pulmonary valve were obtained in 10 normal subjects and 14 patients after Ross operation. Valve morphology and function were analyzed and signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were calculated. Flow measurements were performed in the pulmonary trunk to assess pulmonary regurgitation. RESULTS: In all subjects, tricuspid morphology of the pulmonary valve was visualized. SNR of the leaflets in normal subjects (9.8 +/- 3.0) and in patients after Ross operation (7.5 +/- 2.2) differed significantly from blood (12.6 +/- 3.2 and 11.3 +/- 2.5, respectively, p < 0.05). Valvular regurgitation was seen in 5 patients as an insufficient closure of the valve which was confirmed by flow measurements. CONCLUSION: Cine MR enables in-plane visualization of the pulmonary valve and allows for functional and morphological evaluation in patients after pulmonary valve surgery.

Adult↗
PubMed2003

Reoperation in a Jehovah's Witness 22 years after aortic allograft reconstruction of the right ventricular outflow tract.

We report the case of a 29-year-old male Jehovah's Witness who presented with hemolysis and right heart failure as a consequence of extreme calcification of an aortic valve-containing allograft and Dacron prosthesis that had been placed 22 years earlier to repair tetralogy of Fallot. Reoperation had been denied by several other centers, because of the patient's refusal to undergo blood transfusion. For 2 weeks preoperatively, we raised the patient's hemoglobin level by treating him with recombinant erythropoietin, oral iron, and folic acid. At surgery, under normothermic cardiopulmonary bypass, we replaced the aortic allograft in the right ventricular outflow tract with a cryopreserved pulmonary allograft, also containing a valve. The postoperative course was uneventful, and the patient was released from the hospital on the 13th postoperative day in excellent condition.

Adult↗
PubMed2001

[Left ventricular reduction surgery: pre- and postoperative evaluation by cine MRI].

AIM: To evaluate the role of cine magnetic resonance imaging (MRI) in the preoperative assessment and postoperative follow-up of patients undergoing left ventricular (LV) reduction surgery. PATIENTS AND METHODS: 6 patients with cardiomegaly were examined on a 1.5 T MR imager before and after LV reduction surgery. The heart was imaged along the short and long axes using a breath-hold ECG-triggered cine gradient-echo sequence for assessing ventricular and valvular morphology and function and performing volumetry (end-diastolic and end-systolic volumes, ejection fraction). RESULTS: Postoperatively, the mean ejection fraction increased from 21.7% to 33.4% and the end-diastolic and end-systolic left ventricular volumes decreased in all patients (304.0 and 252.5 ml before to 205.0 and 141.9 ml after surgery). Mean myocardial mass decreased slightly from 283.8 g to 242.7 g. Differences were significant for all parameters (p < 0.05). MRI allowed for the reliable assessment of post-operative valve morphology and yielded additional findings such as the presence of mitral valve insufficiency or ventricular thrombus. CONCLUSIONS: Cine MRI provides relevant information prior to left ventricular reduction surgery and reliably depicts functional and morphological changes in the early post-operative follow-up.

Aged↗
PubMed2001

Magnetic resonance imaging of stentless xenografts for reconstruction of right ventricular outflow tract.

The objective was to overcome allograft shortage during the Ross operation; stentless xenografts were carefully evaluated for hemodynamic behavior and valve deterioration during medium term follow-up. Between January 10, 1994 and January 4, 1996 nine adult patients (age 31-51 years) underwent aortic valve replacement with an autologous pulmonary valve and right ventricular outflow tract reconstruction with the Edwards Prima or Medtronic Freestyle xenograft. One patient was dead early and one late, both from noncardiac reasons. Forty-eight to 66 months follow-up was available for 7 patients and was performed with physical examination in the outpatient clinic, transthoracic echocardiography (TTE), and magnetic resonance imaging (MRI). Two patients received 29-mm valves and the remaining 27-mm valves. No reoperation became necessary during follow-up. Preoperative left ventricular ejection fraction ranged from 20% to 84%, median 61%, mean 59% +/- 18%. At latest follow-up left ventricular ejection fraction was 49% to 70%, median 57%, mean 58% +/- 8%. TTE showed no calcification of the xenograft wall or cusps. MRI revealed good autograft function with no evidence of stenosis in any patient. Four patients showed no and three trivial regurgitation. Right ventricular outflow tract-stenosis could not be seen in any patient. Calculated gradients of the xenograft valves ranged from 2 to 6 mm Hg, median 3 mm Hg (mean 3.1 +/- 2.4 mm Hg) and calculated EOA ranged from 2.0 to 4.0 cm(2), median 2.8 cm(2). MRI supported these findings and showed pliable xenograft cusps in all patients. Right ventricular function was well preserved in all patients. In adult patients right ventricular outflow tract reconstruction with stentless xenografts can be performed safely and intermediate-term results are encouraging. During medium-term (5-7 years) follow-up no calcification or deterioration of valve function occurred with excellent hemodynamic behavior.

Adult↗