Easy Pulsatile Phantom for Teaching and Validation of Flow Measurements in Ultrasound.

PURPOSE: To build a simple model to teach and validate non-pulsatile and pulsatile flow quantification in ultrasound. MATERIALS AND METHODS: The setting consists of the following connected components: (1) medical syringe pump producing an adjustable constant flow (ml/min), (2) modulator modifying constant flow to a reproducible pulsatile flow, (3) water tank containing a diagonal running silicone tube (0.5 mm inner diameter), and (4) a fixated ultrasound probe (L9 Linear Array 9 MHz, GE Logiq E9) measuring the flow inside the tube. Commercially available microbubbles suspended with physiological saline solution were used for ultrasonic visibility. Spectral Doppler of different flow profiles is performed. RESULTS: The syringe pump produces an adjustable, constant flow and serves as the reference standard. The filling volume of the tube system is 1.2 ml. Microbubbles are very well detected by ultrasound and can be used as an easy and clean blood mimicking substance. The modulator generates different physiological and pathological flow profiles. Velocities are similar to those found within human blood vessels. Thus, it is possible to train and validate flow measurements in ultrasound. CONCLUSION: The model produces non-pulsatile and various pulsatile flow profiles and allows validation of flow measurements. The compact size permits easy and economic setup for flow measurements in research, skills lab and continuing education.

A new method to assess ventricular wall stress in patients with heart failure and its relation to heart rate variability.

INTRODUCTION: Heart failure is characterized by an increase in cardiac load, wall stress and autonomic dysfunction. The neurohumoral imbalance arising from adrenergic activation and parasympathetic withdrawal is associated with worse prognosis. We addressed the hypothesis that an increased left ventricular (LV) wall stress as assessed by cardiac magnetic resonance imaging (CMR) in patients with heart failure is related to a depression of heart rate variability (HRV). METHODS: Cardiac function and mass were measured in 37 individuals with suspected cardiomyopathy using CMR imaging. A thick-walled sphere model was used to calculate ventricular wall stress. Time domain analysis of HRV was obtained by long-term Holter ECG. RESULTS: Standard deviation of both normal-to-normal (NN) intervals (SDNN) and average NN intervals over 5 minutes (SDANN-i) were negatively correlated with LV enddiastolic wall stress (r = 0.42, P < 0.01). SDNN and SDANN-i were severely decreased (P < 0.01) in patients with increased enddiastolic LV wall stress > 12 kPa (vs. normal range: < 4 kPa). CONCLUSION: A relation between increased cardiac wall stress and depressed heart rate variability was observed in patients with heart failure. CMR-based measurement of LV volume and mass is appropriate to calculate LV wall stress which should be considered not only as a potential prognostic determinant but also as therapeutic target.

B-type natriuretic peptide and wall stress in dilated human heart.

Background Although B-type natriuretic peptide (BNP) is used as complimentary diagnostic tool in patients with unknown thoracic disorders, many other factors appear to trigger its release. In particular, it remains unresolved to what extent cellular stretch or wall stress of the whole heart contributes to enhanced serum BNP concentration. Wall stress cannot be determined directly, but has to be calculated from wall volume, cavity volume and intraventricular pressure of the heart. The hypothesis was, therefore, addressed that wall stress as determined by cardiac magnetic resonance imaging (CMR) is the major determinant of serum BNP in patients with a varying degree of left ventricular dilatation or dysfunction (LVD). Methods A thick-walled sphere model based on volumetric analysis of the LV using CMR was compared with an echocardiography-based approach to calculate LV wall stress in 39 patients with LVD and 21 controls. Serum BNP was used as in vivo marker of a putatively raised wall stress. Nomograms of isostress lines were established to assess the extent of load reduction that is necessary to restore normal wall stress and related biochemical events. Results Both enddiastolic and endsystolic LV wall stress were correlated with the enddiastolic LV volume (r = 0.54, P < 0.001; r = 0.81, P < 0.001). LV enddiastolic wall stress was related to pulmonary pressure (capillary: r = 0.69, P < 0.001; artery: r = 0.67, P < 0.001). Although LV growth was correlated with the enddiastolic and endsystolic volume (r = 0.73, P < 0.001; r = 0.70, P < 0.001), patients with LVD exhibited increased LV wall stress indicating an inadequately enhanced LV growth. Both enddiastolic (P < 0.05) and endsystolic (P < 0.01) wall stress were increased in patients with increased BNP. In turn, BNP concentration was elevated in individuals with increased enddiastolic wall stress (>8 kPa: 587 +/- 648 pg/ml, P < 0.05; >12 kPa: 715 +/- 661 pg/ml, P < 0.001; normal < or =4 kPa: 124 +/- 203 pg/ml). Analysis of variance revealed LV enddiastolic wall stress as the only independent hemodynamic parameter influencing BNP (P < 0.01). Using nomograms with "isostress" curves, the extent of load reduction required for restoring normal LV wall stress was assessed. Compared with the CMR-based volumetric analysis for wall stress calculation, the echocardiography based approach underestimated LV wall stress particularly of dilated hearts. Conclusions In patients with LVD, serum BNP was increased over the whole range of stress values which were the only hemodynamic predictors. Cellular stretch appears to be a major trigger for BNP release. Biochemical mechanisms need to be explored which appear to operate over this wide range of wall stress values. It is concluded that the diagnostic use of BNP should primarily be directed to assess ventricular wall stress rather than the extent of functional ventricular impairment in LVD.

A new methodological approach to assess cardiac work by pressure-volume and stress-length relations in patients with aortic valve stenosis and dilated cardiomyopathy.

In experimental animals, cardiac work is derived from pressure-volume area and analyzed further using stress-length relations. Lack of methods for determining accurately myocardial mass has until now prevented the use of stress-length relations in patients. We hypothesized, therefore, that not only pressure-volume loops but also stress-length diagrams can be derived from cardiac volume and cardiac mass as assessed by cardiac magnetic resonance imaging (CMR) and invasively measured pressure. Left ventricular (LV) volume and myocardial mass were assessed in seven patients with aortic valve stenosis (AS), eight with dilated cardiomyopathy (DCM), and eight controls using electrocardiogram (ECG)-gated CMR. LV pressure was measured invasively. Pressure-volume curves were calculated based on ECG triggering. Stroke work was assessed as area within the pressure-volume loop. LV wall stress was calculated using a thick-wall sphere model. Similarly, stress-length loops were calculated to quantify stress-length-based work. Taking the LV geometry into account, the normalization with regard to ventricular circumference resulted in "myocardial work." Patients with AS (valve area 0.73+/-0.18 cm(2)) exhibited an increased LV myocardial mass when compared with controls (P<0.05). LV wall stress was increased in DCM but not in AS. Stroke work of AS was unchanged when compared with controls (0.539+/-0.272 vs 0.621+/-0.138 Nm, not significant), whereas DCM exhibited a significant depression (0.367+/-0.157 Nm, P<0.05). Myocardial work was significantly reduced in both AS and DCM when compared with controls (129.8+/-69.6, 200.6+/-80.1, 332.2+/-89.6 Nm/m(2), P<0.05), also after normalization (7.40+/-5.07, 6.27+/-3.20, 14.6+/-4.07 Nm/m(2), P<0.001). It is feasible to obtain LV pressure-volume and stress-length diagrams in patients based on the present novel methodological approach of using CMR and invasive pressure measurement. Myocardial work was reduced in patients with DCM and noteworthy also in AS, while stroke work was reduced in DCM only. Most likely, deterioration of myocardial work is crucial for the prognosis. It is suggested to include these basic physiological procedures in the clinical assessment of the pump function of the heart.

Relation of B-type natriuretic peptide to left ventricular wall stress as assessed by cardiac magnetic resonance imaging in patients with dilated cardiomyopathy.

Ventricular loading conditions are crucial determinants of cardiac function and prognosis in heart failure. B-type natriuretic peptide (BNP) is mainly stored in the ventricular myocardium and is released in response to an increased ventricular filling pressure. We examined, therefore, the hypothesis that BNP serum concentrations are related to ventricular wall stress. Cardiac magnetic resonance imaging (MRI) was used to assess left ventricular (LV) mass and cardiac function of 29 patients with dilated cardiomyopathy and 5 controls. Left ventricular wall stress was calculated by using a thick-walled sphere model, and BNP was assessed by immunoassay. LV mass (r = 0.73, p < 0.001) and both LV end-diastolic (r = 0.54, p = 0.001) and end-systolic wall stress (r = 0.66, p < 0.001) were positively correlated with end-diastolic volume. LV end-systolic wall stress was negatively related to LV ejection fraction (EF), whereas end-diastolic wall stress was not related to LVEF. BNP concentration correlated positively with LV end-diastolic wall stress (r = 0.50, p = 0.002). Analysis of variance revealed LV end-diastolic wall stress as the only independent hemodynamic parameter influencing BNP (p < 0.001). The present approach using a thick-walled sphere model permits determination of mechanical wall stress in a clinical routine setting using standard cardiac MRI protocols. A correlation of BNP concentration with calculated LV stress was observed in vivo. Measurement of BNP seems to be sufficient to assess cardiac loading conditions. Other relations of BNP with various hemodynamic parameters (e.g., EF) appear to be secondary. Since an increased wall stress is associated with cardiac dilatation, early diagnosis and treatment could potentially prevent worsening of the outcome.

MR imaging of compartment syndrome of the lower leg: a case control study.

The aim of this study was to evaluate the use of MR imaging for diagnosis and therapy management of compartment syndromes. In total, 15 patients (5 with an imminent compartment syndrome and 10 with manifest compartment syndrome) underwent MR imaging with a variety of pulse sequences including fat suppression, magnetization transfer imaging, and intravenous gadopentetate dimeglumine (Gd-DTPA) administration. Early and late follow-up MR images were obtained. Manifest compartment syndromes showed swollen compartments with loss of normal muscle architecture on T1-weighted spin-echo images. T2-weighted spin-echo and magnetization transfer imaging showed bright areas, which enhanced after Gd-DTPA. Early follow-up showed changes in enhancement patterns; late follow-up showed fibrosis and cystic and fatty degenerations of the affected compartments. MR imaging can help make the diagnosis of a manifest compartment syndrome in clinically ambiguous cases. It points out the affected compartments and allows the surgeon to selectively split the fascial spaces.

[Biventricular MR volumetric analysis and MR flow quantification in the ascending aorta and pulmonary trunk for quantification of valvular regurgitation]. / Biventrikuläre MR-Volumetrie und MR-Flussmessungen in Aorta ascendens und Truncus pulmonalis zur Quantifizierung von Klappeninsuffizienzen.

PURPOSE: To test the value of biventricular volumetric analysis and the combination of biventricular volumetric analysis with flow quantification in the ascending aorta (Ao) and pulmonary trunk (Pu) for quantification of regurgitation volume and cardiac function in valvular regurgitation (VR) according to location and presence of single or multivalvular disease. MATERIALS AND METHODS: In 106 patients, the stroke volumes were assessed by measuring the biventricular volumes and the forward-stroke volumes in the great and small circulation by measuring the flow in the Ao and Pu. Valve regurgitation volumes and quotients were calculated for single and multivalvular disease and correlated with semiquantitative 2D-echocardiography (grade I-IV). For the assessment of the cardiac function in VR, the volumetric parameters of ejection fraction and end-diastolic (EDV) and end-systolic (ESV) volumes were determined. RESULTS: The detection rate was 49% for left ventricular (LV) VR and 42% for right ventricular (RV) VR. Low LV VR and RV VR usually could not be detected quantitatively, with the detection rate improving with echocardiographically higher insufficiency grades. Quantitative MRI could detect a higher grade solitary aortic valve insufficiency (> or = 2) in 11 of 12 patients and higher grade mitral valve insufficiency in 4 of 10 patients. A significant increase in RV and LV ventricular EDV and ESV was seen more often with increased MR regurgitation volumes. Aortic stenosis did not interfere with flow measurements in the Ao. CONCLUSIONS: Biventricular volumetry combined with flow measurements in Ao and Pu is a robust, applicable and simple method to assess higher grade regurgitation volumes and the cardiac function in single and multivalvular regurgitation at different locations. It is an important application for the diagnosis of VR by MRI.

[Comparison between biventricular cine MRI and MR flow quantification in ascending aorta and pulmonary outflow tract for the assessment of intracardial shunt volumes]. / Vergleich von biventrikulärer MR-Volumetrie und MR-Flussmessungen in Aorta ascendens und Truncus pulmonalis zur intrakardialen Shuntbestimmung.

PURPOSE: Comparison between biventricular volumetric measurements and flow measurements in ascending aorta (Ao) and pulmonary outflow tract (Pu) for quantification of intracardial shunts, and evaluation of the combination of biventricular cine MRI with flow measurements for the assessment of RV and LV heart failure and valvular regurgitation (VR). MATERIAL AND METHODS: In 24 patients, right (RV) and left (LV) ventricular volumetric and flow measurements were performed in the Ao and Pu to assess the ratio of RV stroke volume (SV) or, respectively, pulmonary SV to LV SV or, respectively, systemic aortic SV (Qp/Qs). 34 patients without echocardiographically proven shunt or VR served as control group for measurement accuracy. Left-to-right shunt ratios were calculated from RV and LV SV, Pu and Ao SV, Pu and LV SV, and RV and Ao SV. Left ventricular VR was calculated by the difference of LV SV and Ao SV, and right ventricular VR by the difference of RV SV and Pu SV. Global systolic function was evaluated by biventricular cine MRI. RESULTS: Intracardial shunts with Qp/Qs > 1.16 can be quantified by flow measurements in Ao and Pu. Using biventricular volumetric measurements in cases without VR, requires a Qp/Qs > 1.21. 17 of 18 intracardiac shunts were identified on MRI, and all 8 hemodynamically significant shunts were quantitatively confirmed. The diagnosis of complete shunt closure or absent shunt was correctly made in all 6 cases. RV EF reduction was found in 6 of 24 patients. LV EF reduction was also found in 6 of 24 patients. CONCLUSION: Flow measurements in Ao and Pu are more accurate than biventricular cine MRI for the assessment of Qp/Qs ratios. Flow measurements in Ao and Pu combined with biventricular cine MRI enables the quantification of hemodynamic significant shunts, higher grade VR and biventricular global systolic function with a single examination.

[Comparison between fast MR flow quantification in breathhold technique in ascending aorta and pulmonary trunc with right and left ventricular cine-MRI for the assessment of stroke volumes in healthy volunteers]. / Vergleich von schneller MR-Flussmessung in Atemanhaltetechnik in Aorta ascendens und Truncus pulmonalis mit rechts- und linksventrikulärer Cine MR-Bildgebung zur Schlagvoluminabestimmung bei Probanden.

PURPOSE: Evaluation of accordance and reproducibility of the stroke volume assessment of fast flow measurement in breathhold technique in the ascending aorta and pulmonary trunc with fast right (RV) and left ventricular (LV) cine-MRI. MATERIAL AND METHODS: The correlation an accordance of stroke volumes (SV) were evaluated by flow measurements in the ascending aorta and pulmonary trunc and RV and LV volumetric cine-MRI in 33 cardiac healthy volunteers. Interobserver and intraobserver variability of the different measurement methods and locations were checked in 10 cardiac healthy volunteers. RESULTS: With respect to the early systolic flow and the extrapolation of the endiastolic flow rate the difference in SV was smaller than 1,5 ml/m(2) for all possible combinations. The interobserver and intraobserver variabilities of flow measurements were significantly lower by approximately a factor of 2.5 than those of RV and LV cine-MRI. CONCLUSION: The accordance of fast prospective triggered flow measurements in the ascending aorta and pulmonary trunc with RV and LV cine-MRI can be achieved with reasonable limits of agreement. Flow measurements are more reproducible than cine-MRI.

[Evaluation of left ventricular aneurysms before and after surgery using Cine-MRI]. / Prä- und postoperative Evaluation von linksventrikulären Herzspitzenaneurysmen mittels Cine-MRT.

PURPOSE: To demonstrate the usefulness of cine-MRI for the evaluation of apical left ventricular aneurysms (ALVA) and for prediction of the surgical outcome. MATERIALS AND METHODS: We investigated 28 patients with ALVA, 13 of them additionally after aneurysmectomy at 1.5 T; 15 healthy volunteers served as normal controls. For cine-MRI k-space segmented Fl-2D-GE sequences were used. Analysis comprised the calculation of cardiac volume indices, cardiac function, and percentual myocardial thickening (PMT). For prediction of surgical results we divided left ventricle into an aneurysmatic and a non-aneurysmatic part. The non-aneurysmatic part was assumed as the left ventricle after surgical remodelling. RESULTS: Enddiastolic and endsystolic volume indices (EDVIs and LV-ESVIs) were higher in patients with ALVA (123.7 +/- 30.2 ml/m(2), 94.3 +/- 32.5 ml/m(2), respectively) than in volunteers (79.1 +/- 13.9 ml/m(2), 25.5 +/- 5.1 ml/m(2), respectively) (p < 0.001). Stroke volume index (SVIs), cardiac index (CIs) and ejection fraction (EFs) were significantly lower in patients (30.4 +/- 9.1 vs. 54.2 +/- 0.2 ml/beat/m(2); 2.2 +/- 0.8 vs. 3.9 +/- 0.9 l/min/m(2), 26.0 +/- 9.7 vs. 67.9 +/- 4.5 %, respectively) (p < 0.001). There was a significant decrease of LV-EDVIs and LV-ESVIs (102.8 +/- 30.3 ml/m(2), 66.3 +/- 28.0 ml/m(2), respectively) (p = 0,002, p < 0.001, respectively), no change of SVIs (36.4 +/- 6.0 ml/beat/m(2)) (p > 0.05) and a significant increase of CIs and EFs (3.0 +/- 0.6 l/min/m(2), 37.91 +/- 10.15 %, respectively) (p < 0.001) after surgery. We found a good correlation between the preoperatively calculated (32.6 +/- 10.1 %) and the measured EF after surgery (37.9 +/- 9.8 %) (r = 0.70; p = 0.035). PMT was significantly lower in patients than in volunteers (median 11.9 +/- 10.7 vs. 70.2 +/- 13.9 %; p < 0.001), especially in the aneurysmatic parts of left ventricle (median - 6.8 %; p < 0.001). CONCLUSION: Cine-MRI offers accurate evaluation of ALVA and enables preoperative estimation of left-ventricular volumes after surgery.

[Left ventricular heart volume determination with fast MRI in breath holding technique: how different are quantitative heart catheter, quantitative MRI and visual echocardiography?]. / Linksventrikuläre Herzvoluminabestimmung mittels schneller MRT in Atemanhaltetechnik: Wie unterschiedlich sind quantitativer Herzkatheter, quantitative MRT und visuelle Echokardiographie?

GOAL: Comparison of fast MRI, echocardiography (Echo), and ventricular angiography (Cath) in the assessment of left ventricular global function. METHODS: Fast MRI in short axis plane, biplane Cath, and 2D Echo were performed in 62 patients [35 coronary artery diseases, 16 acquired valvular diseases (VD), 9 dilated cardiomyopathies (DCM), 1 congenital heart disease and 1 heart transplantation]. Enddiastolic (EDV), endsystolic (ESV), stroke volumes (SV), cardiac output (CO), and ejection fraction (EF) were compared in MRI and Cath. EF was visually estimated in 2D Echo by an experienced observer. RESULTS: In comparison to MRI, Cath overestimated EF by 8.4%, and Echo underestimated EF by 5.6%. The limits of agreement between MRI and Cath in EF were +/- 23.8%, between MRI and Echo +/- 18%, and between Echo and Cath +/- 19.4%. Significant differences were found between Cath and MRI in EDV, SV, and CO, but not for ESV. The best agreement in EF was found in the group with DCM, the worst in the group with VD. CONCLUSION: Important systemic and random errors were found in the comparison of MRI, Echo, and Cath. For therapy decision and follow-up, the methods should not be exchanged unscrupulously.

Right ventricular volumes and ejection fraction with fast cine MR imaging in breath-hold technique: applicability, normal values from 52 volunteers, and evaluation of 325 adult cardiac patients.

Our goal was to establish right ventricular (RV) volume and ejection fraction (EF) values in normal volunteers with fast magnetic resonance (MR) imaging using a breath-hold technique, to assess the frequency and severity of RVEF abnormality in cardiac patients and to compare RV with left ventricular (LV) data. We performed simultaneously derived RV and LV fast cine measurements in 52 normals and 325 patients with coronary artery disease (CAD), acquired valvular disease (VD), cardiomyopathy (CM), or congenital heart disease (CHD). RVEF was reduced in 31% (102) of all patients, in 50% dilated CM, 39% CHD, 34% CAD, and 22% acquired VD patients. Solitary abnormally low RVEF was found in only 15/325 (5%) of all patients, whereas combined with LVEF deterioration in 87/172 (51%) patients. RVEF reduction was mild in 64%, moderate in 25%, and severe in 11%. Although RVEF correlated significantly (r = 0.55, P < 0.001) with LVEF, the predictive value of LVEF for RVEF was low. We conclude that RV volumes can be routinely assessed with fast MRI and should be performed in addition to LV evaluation in CHD, in right-sided VD, and in all patients with an abnormal LVEF.J. Magn. Reson. Imaging 1999; 10:908-918.

[Comparison of left and right ventricular ejection and filling parameters of the heart using cine-MRI with breath holding technique. Clinical study of 42 patients with cardiomyopathy and coronary heart disease]. / Vergleich links- und rechtsventrikulärer Auswurf- und Füllungsparameter des Herzens mittels Cine MRT in Atemanhaltetechnik: klinische Studie an 42 Patienten mit Kardiomyopathie und koronarer Herzerkrankung.

PURPOSE: Quantification of left and right ventricular filling and ejection of localized and diffuse heart diseases with fast cine MR imaging in breath-hold technique. METHODS: 42 patients (14 idiopathic dilated cardiomyopathies (DCM), 13 hypertrophic cardiomyopathies (HCM) and 15 coronary artery diseases (CAD)) and 10 healthy volunteers were examined. Time-volume-curves of three left ventricular and one right ventricular slices were evaluated and peak ejection and filling rates (PER, PFR end-diastolic volume (EDV)/s) time to PER and PFR (TPER, TPFR ms) and time of end-systole (TSYS in % RR-intervall) were calculated. RESULTS: There were significant regional and left-/right-sided differences of the filling and ejection of both ventricles within and between the different groups. In DCM the left ventricular PFR was reduced (DCM 3.1 EDV/s; volunteers 4.9 EDV/s) and Z-SYS prolonged (DCM 50.1%; volunteers 35.4%). In CAD there were localized decreased filling rates in comparison to the normal volunteer group (left ventricle: basal: 2.9 and 6.3 EDV/s, apical: 4.4 and 6.3 EDV/s; right ventricle: 3.6 and 5.7 EDV/s). HCM typically showed an isovolumetric lengthening of the endsystole. CONCLUSIONS: Cardiac MR imaging in breath-hold technique is suitable for measuring contraction and relaxation disturbances of localized and diffuse heart diseases by means of ejection and filling volume indices.

[The determination of left and right ventricular ejection and filling functions of the heart by fast cine MRT in the breath-hold technic in subjects]. / Bestimmung des links- und rechtsventrikulären Auswurf- und Füllungsverhalten des Herzens mittels schneller Cine MRT in Atemanhaltetechnik an Probanden.

PURPOSE: Evaluation and comparison of localized and global left and right ventricular ejection and filling with fast cine MR imaging in the breath-hold technique. MATERIALS AND METHODS: 10 healthy volunteers were examined with a 1.5 Tesla unit and phased-array-coil using a segmented FLASH-2D sequence in breath-hold technique. Peak ejection and peak filling rates [PER, PFR end-diastolic volume (EDV)/s)]. time to PER and PFR [TPER, TPFR ms] and time of end-systole [TSYS in % RR-interval] of all slices (complete-slice-evaluation) were evaluated and compared to three left ventricular and one right ventricular slices (reduced three-slice-evaluation). RESULTS: There were significant regional left ventricular differences of PER (p = 0.002) and PFR (p = 0.007), but not of TPER and TPFR. Ejection and filling indices of the left ventricular middle slice were closest to the overall evaluation of all sections. In the left-/right-side comparison the right ventricular PFR was higher than the left ventricular (5.1 and 4.2 EDV/s) and the right ventricular TPFR was earlier than the left (92.2 and 123.5 ms). CONCLUSIONS: With fast cine techniques, regional and global left and right ventricular ejection and filling indices can be evaluated in addition to the global heart volume indices. The three-slice-evaluation represents a comprehensive, clear and time-saving method for daily routine.

[Accuracy of right and left ventricular heart volume and left ventricular muscle mass determination with cine MRI in breath holding technique]. / Genauigkeit der rechts- und linksventrikulären Herzvolumen- und linksventrikulären Muskelmassenbestimmung mittels Cine MRT in Atemanhaltetechnik.

PURPOSE: To assess the accuracy of right- (RV) and left-ventricular (LV) heart volume and muscle mass determinations by cine MR imaging. MATERIALS AND METHODS: Ten subjects were examined twice by a segmented, ECG-triggered cine sequence in the short axis plane and breath-hold technique by two independent operators and again 4 weeks later by one of the operators. The contours were evaluated manually by two independent examiners and again four weeks later by one of the examiners. LV and RV end-diastolic and end-systolic volumes, stroke volume, cardiac output, ejection fraction (EF), and left-ventricular muscle mass were compared. RESULTS: The RV evaluation variations (RV-EF: 6.46%) were higher than the LV (LV-EF: 4.46%). The intra-examiner variations were smaller than the inter-examiner variations. The generally operators did not cause a significantly increased variation (LV-EF: 5.77%). In contrast, the repeat examinations at different times did lead to a significant increase in the variation (LV-EF: 10.15%). CONCLUSIONS: The rapid ECG-triggered cine MRI in breath-hold technique allows the simultaneous RV and LV, artefact-free determination of heart volumes and LV muscle mass. The LV volumes can be determined more accurately than the RV. The examiner has a distinct influence on the accuracy, the operator has a lesser effect. Physiological fluctuations of cardiac activity significantly influence the follow-up.

[Value of ultrasound and magnetic resonance imaging in the control of the postoperative progress after Achilles tendon rupture]. / Der Wert von Ultraschall und Magnetresonanztomographie in der postoperativen Verlaufskontrolle nach Achillessehnenruptur.

AIM: A comparison of clinical examination, sonography and MRI in the follow-up of suture of the Achilles tendon. METHOD: 60 patients were examined in a prospective study for 6-78 months following suture of the Achilles tendon repair; both sides were compared clinically and sonographically; in 30 patients MRI was also used. Morphometric measurements (antero-posterior and transverse measurements) and changes in morphological structure were correlated with clinical results. RESULTS: All patients showed thickening of the Achilles tendon postoperatively. Morphometric and morphological changes showed positive and significant correlation between sonography and MRI (p = < 0.001, p = 0.004). Structural changes in sonography had positive correlation with general symptoms (p = < 0.001), pain on movement (p = < 0.001), reduced function (p = 0.005), and reduced sporting activity (p = 0.034). MRI findings showed significant regression with time (p = 0.05). CONCLUSION: Following repair, the Achilles tendon remained thickened throughout the period of observation. Post-operative changes in the structure of the tendon regressed partially. Sonography and MRI correlate significantly with the clinical findings. Sonography is the imaging method of choice, MRI is an additional procedure.

Diagnosis of rotator cuff lesions: comparison of US and MRI on 38 joint specimens.

An experimental study was performed on cadaveric joint specimens of the shoulder to determine the accuracy of US and MRI in diagnosis of abnormalities of the rotator cuff. The value of different morphological criteria was evaluated for discrimination of degeneration as well as partial and complete disruption. A total of 38 surgically exposed specimens of the shoulder joint were examined by US, MRI and pathological methods visualising the tendons of the rotator cuff in same axial and longitudinal orientations. The three imaging modalities were reviewed separately by experienced examiners, respectively, who were blind to other results. Evaluation criteria consisted of signs of shape (thinning, thickening, discontinuity and absence of rotator cuff) and structure (changes in echogenicity in US, increased signal intensity in MRI, tissue changes in pathology). Findings in US and MRI were finally compared with pathology to assess sensitivity and specificity. Pathology demonstrated 4 full-thickness tears, 6 partial-thickness tears, 16 cases with degeneration and 12 normal rotator cuffs. Ultrasound showed pathological signs in all abnormal cuffs, and one MRI report was false negative. Specificity was 67 % in US (4 of 12 cases were false positive) and 100 % in MRI (no abnormal findings in healthy tendons). Discrimination of different pathological disorders of the rotator cuff was reduced in both methods. Using US only 10 of 16 cases of degeneration, 2 of 6 partial tears and 3 of 4 complete tears were correctly defined. Using MRI 13 of 16 degenerations, 3 of 6 partial tears and 3 of 4 complete tears were detected. The MRI technique failed to visualise intratendinous calcifications in all 3 cases. We conclude that MRI and US are both sensitive in detection of abnormalities of the rotator cuff. Ultrasound should be the primary diagnostic method in screening of shoulder pain because it is economic and fast. The MRI technique should be used secondary because it provides more information about extent of tendons and has lower risk of artefacts.

MR imaging of anatomy and tears of wrist ligaments.

Numerous intrinsic and extrinsic wrist ligaments are visible at magnetic resonance (MR) imaging. Because the previously published descriptions of these ligaments were often conflicting, the authors derived a classification system based on a functional perspective and their experience with MR imaging, arthroscopy, and surgical dissection. This system was used to evaluate MR images of 23 cadaveric wrists for the presence and integrity of 16 wrist ligaments. MR images were prospectively analyzed by two observers, and all findings were correlated with the results of arthroscopy. The best detection rates and diagnostic confidence rates were achieved for the triangular fibrocartilage (100% and 100%, respectively) and the scapholunate ligament (91% and 87%, respectively). Other ligaments were less well seen, partly because of their size and course. Eighty-two percent of the triangular fibrocartilage tears, 50% of the scapholunate tears, and 40% of the lunotriquetral tears seen at arthroscopy were detectable on MR images. Identification of these three types of tears on MR images is important because they are functionally significant and because there are accepted methods of treating them in orthopedic practice.