[Cardiac MR flowmetry: experimental validation and results in patients with operated heart defects]. / Kardiale MR Flussmessungen: Experimentelle Validierung und Ergebnisse bei Patienten mit operierten Herzfehlern.

PURPOSE: A flow-sensitive MR sequence (phase-contrast technique) was evaluated in phantom studies with regard to factors influencing measurements and correctness of results. The sequence was additionally used for functional evaluation of operated congenital heart disease. METHODS: Pulsatile and constant flow were produced with the help of a phantom. Influence of angulation, range and vessel bending was evaluated. An examination protocol was developed from the results. 35 patients with surgically repaired congenital heart disease or without repair were examined. RESULTS: A range preset below the actual flow velocity as well as angulation of more than 20 degrees were isolated as main pitfalls in MR flowmetry. In addition to morphological MR findings flow measurements were possible in 11 patients at vessel sites which were not or not completely suited for examination by Doppler ultrasound. CONCLUSION: The evaluated phase-contrast technique allows for fast and reliable flow quantification if the influences identified in phantom studies are considered.

[Pre- and postoperative evaluation of ventricular function, muscle mass and valve morphology by magnetic resonance tomography in Ebstein's anomaly]. / Prä- und postoperative Beurteilung der ventrikulären Funktion, Muskelmasse und Klappenmorphologie bei der Ebstein-Anomalie mit der Magnetresonanztomographie.

PURPOSE: To evaluate the value of MRT with spin echo (SE) and CINE gradient echo (GE) sequences for the pre- and postoperative assessment of patients with Ebstein's anomaly. METHODS: Twelve patients within the ages of four to 49 years (mean 22 +/- 12 years) were examined pre- (n = 5) or postoperatively (n = 7) after tricuspid valve reconstruction with a 1.5 T scanner. For the anatomical assessment, an ECG-gated transverse SE-sequence, for the assessment of valve morphology and function as well as for volumetry a CINE GE-sequence with retrospective gating was used. With the use of the multislice-multiphase technique, after summing up the manually outlined epi- and endocardial areas, endsystolic (ESV) and enddiastolic volumes (EDV), ejection fraction (EF), stroke volume (SV), and muscle mass (MM) were calculated for both ventricles. RESULTS: The differentiation of the displaced parts of the tricuspid valve (TV) was insufficient with static SE, but was possible in all patients with CINE-MRT. Like in Doppler echocardiography, a qualitative assessment of tricuspid insufficiency was possible in CINE-MRT, the mean incompetence grade preoperative was 1.8 (+/- 0.8), postoperative 0.7 (+/- 0.5). The mean RV-EF in the preoperative group was 41.8% (+/- 6.4), in the postoperative group 47.9% (+/- 10.6), the mean LV-EF preoperative 47.4% (+/- 8.5%), postoperative 63.0% (+/- 9.4). CONCLUSION: CINE-MRT should rather be used than SE for the assessment of valve morphology. EF, muscle mass and tricuspid incompetence can also be calculated pre- and postoperative with CINE-MRT.

[The value of magnetic resonance tomography (MRT) for evaluating ventricular and anastomotic functions in patients with an extra- or intracardiac total cavopulmonary connection (TCPC)-modified Fontan operation]. / Wertigkeit der Magnetresonanztomographie (MRT) zur Beurteilung der Ventrikel- und Anastomosen-Funktion bei Patienten mit extra- oder intrakardialer totaler cavopulmonaler Anastomose (TCPC)-modifizierte Fontan-Operation.

PURPOSE: To evaluate different MR methods (ventricle and flow measurements) for the postoperative follow-up of hemodynamics in patients with extra- or intracardial TCPC. MATERIALS AND METHODS: Twenty-eight consecutive patients (14 female, 14 male) within the ages of two to thirty-eight years were examined using a 1.5 T Gyroscan ACS-NT scanner (Philips, Best, Netherlands). 7 patients had an extracardial (eTCPC), and 21 an intracardial (iTCPC) tunnel. The calculation of the ventricular function and muscle mass was performed using "multislice-multiphase" technique by summing up the end-diastolic and end-systolic areas; the flow measurements were evaluated by phase shift velocity mapping in the superior vena cava (SVC), inferior vena cava (IVC), right (RPA) and left (LPA) pulmonary artery. Besides peak and mean velocity, the mean and maximal flow volumes (ml/min) were calculated. RESULTS: Ejection fraction (EF) of the functionally single ventricle was within the normal range (mean 57%) in 22/28 patients while mean muscle mass was elevated in the group with eTCPC (mean 121 g/m2). The mean flow volumes and the peak velocities in all vessels were higher in the group with iTCPC as compared to the one with eTCPC. Clinically relevant retrograde flows in the IVC were only found in the group with iTCPC (7/21), as well as a significant predominant flow distribution towards the RPA (p < 0.05; Wilcoxon signed-rank test); in the group with eTCPC towards the LPA (n.s.). CONCLUSIONS: MRI is a useful method for the assessment of ventricular function and muscle mass in the follow-up after the modified Fontan operation. MRI flow measurements additionally provided clinically relevant information about the hemodynamics in Fontan patients.

[Effects of para- and diamagnetic materials in a 1.5 Tesla high field magnetic resonance tomography system]. / Effekte von para- und diamagnetischen Materialien in einem 1,5-Tesla-Hochfeld-Magnetresonanztomographen (MRT).

This article shows the results of an experimental investigation of the interference by paramagnetic and diamagnetic materials on imaging in a closed 1.5 Tesla high field magnetic resonance imaging system (MRI). For different types of sequences (SE, GE, EPI) the effects of metal and non-metal profiles in producing artefacts were investigated. A phantom (plastic trunk) filled with Gd-Mn-solution was used for representation of the artefacts. The materials analysed were placed parallel to the phantom at predetermined distances. The images were obtained in transverse and sagittal planes and analysed with respect to the resulting artefacts. The results show that aluminum and polymer profiles produce the weakest artefacts, even when the material is positioned close to the phantom. A comparison of the sequence types shows that the SE-sequence has a low sensitivity to artefacts, despite the great profile variation in size and shape. The SE-sequence accordingly showed a higher imaging stability as compared with the GE- and EPI-sequences. Steel and copper produced the strongest artefacts. The examination was begun after an intensive study of the literature (Internet, Medline, Meditec). So far have been few publications on this subject.

New approaches to the measurement of morbidity in intestinal schistosomiasis.

New approaches for the assessment of morbidity due to schistosomiasis infection include the substitution of egg counts by quantitative assays for circulating schistosomal antigens, simple parameters for global immune responsiveness and functional hepatic alterations, and ultrasonography as an imaging technique. Quantification of circulating schistosome antigens in sera of S. mansoni, S. haematobium or S. intercalatum infected patients by sensitive immunoassays provides an exact measure for the individual worm burden. The effect of chemotherapy on immunomodulation was assessed by a panel of cutaneous recall antigens. Non-specific cell-mediated immune responses returned to subnormal pretreatment levels in the event of reinfection. Immunological morbidity can be monitored in this way. Pathophysiological alterations of the liver in S. mansoni infection can be assessed by the determination of unconjugated bile acids in the systematic circulation. The regression of intrahepatic vascular lesions in schistosomiasis with hepato(spleno)megaly can be detected earlier by this parameter than by ultrasonography. Ultrasonography provides characteristic, if not pathognomonic, images of Symmers fibrosis, and may be of value in the long-term evaluation of hepatic fibrosis.

[The role of color-coded Doppler sonography in the diagnosis of the veins in the lower extremities in comparison with conventional phlebography]. / Stellenwert der farbkodierten Doppler-Sonographie (FKDS) in der Venendiagnostik der unteren Extremität im Vergleich zur konventionellen Phlebographie.

In 19 patients with suspected DVT of the lower limb, the ability to picture the venous system of the leg and the specificities and sensitivities in the detection of intraluminal clots using color Doppler flow imaging have been evaluated in a prospective study while differentiating between the various vessels and have been compared with conventional venography. The overall results are within the limits of other studies. While color Doppler flow imaging tends to be superior to conventional venography in the thigh, the fibular group in the calf presents as a "problem zone" due to anatomic and technical reasons. In spite of this, color Doppler flow imaging can now be recommended as the primary examination modality for evaluating patients with suspected DVT.

Is there a correlation in breast carcinomas between tumor size and number of tumor vessels detected by gadolinium-enhanced magnetic resonance mammography?

Tumor vessels are known as a sign of malignancy in breast tumors. Is there a correlation between tumor size and the number of vessels in cases of breast tumor examined by dynamic gadolinium (Gd)-enhanced MR imaging? Eighteen patients (mean age, 46 +/- 7 years) underwent dynamic Gd-enhanced MR imaging of the breast by three-dimensional gradient echo sequence using thin-layer technique (2.5 mm) at 1.5T. The dynamic study included one precontrast and four postcontrast sequences (every 90 seconds) in coronal slices. Postprocessing by subtraction method and reconstruction in both transverse and sagittal planes were performed. All carcinomas showed rapid Gd enhancement. Tumor size (0.5 to 31.5 cm3; mean, 6.3 +/- 3.7 cm3) and number of vessels (1 to 10; mean, 3 +/- 2.1) were detected in summation of all three directions. A significant correlation was found between number of vessels and tumor size (r = 0.787, p < or = 0.01). Breast tumor size significantly correlated with the number of vessels detected by Gd-enhanced MR mammography. The introduced method is a further important step in differentiating a carcinoma from a benign lesion.

[Ultrasound examination of the female breast: comparison of 7.5 and 13 MHz]. / Ultraschalluntersuchung der weiblichen Brust: Vergleich von 7.5 und 13 MHz.

PURPOSE: We investigated whether the high resolution ultrasound (13 MHz-scanner) shows smaller lesions and better differentiation than the 7.5 MHz-scanner. METHOD: Prospectively, sonography was performed on forty-seven patients with a 7.5 MHz-scanner as well as with a 13 MHz-scanner in identical slices. RESULTS: Obviously we could obtain more exact diagnoses by using the high resolution scanner. In two patients additional satellite of the primary tumor could be found. In four patients, unclear sonographic findings could be identified as cysts. A disadvantage in the usage of the 13 MHz-scanner is that mastopathy and benign lesions are more difficult to diagnose. With the high resolution more details could be seen although the inhomogeneity as well as the irregularity of the margins are seen more clearly and, therefore, the physician has to reestimate his point of view. To optimize the quality of the pictures made by high resolution ultrasound, it is necessary to regulate the system, which sometimes is quite difficult. CONCLUSION: The recognition of smallest lesions and the reliable presentation of cysts indicates that the 13 MHz-scanner is a good additive diagnostic parameter to the 7.5 MHz-scanner. Therefore, this method may become important for diagnosing multicentrity within carcinomas.

Registered image subtraction for CT-, MR- and coronary angiography.

Conventional post-processing of digital subtraction angiography (DSA) by 3D spiral CT, 3D MRI and 2D DSA is often hampered by extended artefacts due to patient movements during examination. In this paper an image registration procedure prior to the digital subtraction is introduced allowing an enhanced visualization of the contrast agent. The object displacement is detected by analysis of image deformations in small local regions. The motion pattern is used to compute a new synthetic mask of maximum congruence with the contrast medium image. This new mask image is then used in the subsequent subtraction. The algorithm works fully automatically and does not need any interactive placement of landmarks. Results obtained from subtraction of uncorrected and corrected sequences were compared with each other. The registration procedure provided good results in the suppression of subtraction artefacts and in the enhancement of vascular structures. Results are presented from subtraction of 2D and 3D data from CTA, MR mammography and coronary angiography.

[2D and 3D parameter images for the analysis of contrast medium distribution in dynamic CT and MRI]. / 2D- und 3D-Parameterbilder zur Analyse der Kontrastmittelverteilung bei dynamischen CT- und MR-Untersuchungen.

AIM: For dynamic contrast medium (CM) studies, parameter images exploit specific features of the time/intensity curve (TIC) of each pixel and represent these values in a new image. Existing concepts of two-dimensional CM analysis are extended for three-dimensional applications using adequate computer graphic visualization. METHODS: Imaging: intravenous CM injection; first-pass analysis using fast CT acquisition of a single slice; CM accumulation by 40 MR slices (6 sequences every 90 s = 240 images): Software: TIC of arbitrary 2D/3D regions; parameter images: (1) temporal maximum intensity projection (TMIP) of all voxels over time, (2) temporal CM gradients (TG) based on TIC amplitude, (3) TIC slope, (4) time of TIC peak, (5) correlation coefficient to reference TIC. The calculated 3D data of CM accumulation was visualized using multiplanar reformation, MIP, surface reconstruction, volume rendering, texture mapping and animation. RESULTS: In first-pass analyses, TMIP and TG allowed the simultaneous or separated presentation of different temporal phases of the CM bolus. Correlation images emphasized regions with similarities to given TIC patterns. Three-dimensional computer graphic techniques enabled (1) anatomical/functional mapping of original image and CM accumulation and (2) fused display of both spatial CM enhancement and color-encoded time of TIC peak in one common image. CONCLUSIONS: The quantification of presence, magnitude, and time-of-peak of CM accumulation in local image regions supports the assessment of vascularization and of ischemic or necrotic areas.

Comparison of various imaging methods with particular evaluation of color Doppler sonography for planning surgery for breast tumors.

OBJECTIVE: Color Doppler sonography (CD) was compared with other diagnostic imaging methods [mammography (MG), breast ultrasound (US) and magnetic resonance imaging (MRI)] in the planning of surgery for breast tumors. MATERIALS AND METHODS: 99 patients with breast cancer and 101 with ultimately benign breast lesions were examined preoperatively. The specificity and sensitivity were calculated, as well as the predictive values. Various qualitative and semiquantitative CD parameters were also analysed for their diagnostic value. RESULTS: The sensitivity/specificity of the various methods (in %) was: MG 85/77; US 95/80; CD 82/75; MRI 90/63. The positive predictive value (ppv)/negative predictive value (npv) (in %) was: MG 79/83; US 81/94; CD 72/84; MRI 79/63. The median maximum systolic flow velocity and the resistance index (RI) were significantly higher in breast cancer vessels than in benign lesions. The number of pulsating color pixels detected by CD was significantly higher for breast cancer. In cases of breast cancer significantly more blood flows were detected in the body of the tumor than at its periphery. CONCLUSION: Color Doppler sonography was not superior to other diagnostic methods for preoperative assessment of a breast lesion. The combination of all diagnostic procedures gave a correct classification rate of 93.3% and is much better than the correct classification of any single diagnostic imaging procedure.

[MR urography with the T2-weighted turbo-spin-echo sequence]. / MR-Urographie mit der T2-gewichteten Turbospinechosequenz.

Tumor-induced dilatation of the urinary tract is difficult to diagnose in the distal part of the ureter, including the stenosis, by ultrasound and X-ray. Often on account of renal insufficiency and allergy, i.v.-contrast media cannot be used. The present study should show the suitability of fast T2-weighted (turbo-) spin-echo sequences (T2-TSE) for MR-urography (MRU). Seven patients (62.3 +/- 6.1 years) were examined in the coronal plane with T2-TSE sequence (TR = 4500 ms, TE = 160 ms) and an MRU was calculated by using the MIP method (maximal intensity projection). This technique enabled urogram-like morphological representation of dilated urinary tract including stenosis in 6 of 7 patients. Assuming a high magnetic field homogeneity, MRU by using a T2-TSE-sequence, without i.v.-contrast media administration, can visualize the urinary tract dilatation and localize tumor-induced stenosis.

Peripheral washout sign on contrast-enhanced MR images of the breast.

PURPOSE: To assess the value of the peripheral washout sign on delayed contrast material-enhanced magnetic resonance (MR) images in differentiation of benign from malignant breast masses. MATERIALS AND METHODS: In 49 women with 79 breast lesions (55 malignant and 24 benign), dynamic contrast-enhanced MR imaging was performed every 90 seconds during the first 7 minutes and repeated at 10, 20, 30, 40, 50, and 60 minutes after injection of contrast material. Qualitative analysis of the images was performed to evaluate the presence of the peripheral washout sign (a hypointense zone in the periphery of the lesion relative to the center). Quantitative analysis of the images was performed by measuring the signal intensity of the periphery and center of the lesions. RESULTS: The peripheral washout sign was seen in 28 (51%) of the 55 carcinomas on delayed contrast-enhanced MR images (> 10 minutes). Quantitative analysis demonstrated different enhancement profiles of the periphery and center of these lesions. The periphery showed early increase and decrease of enhancement, while the center showed gradual increase and persistent enhancement. The peripheral washout sign was not seen in any of the benign lesions. Specificity was 100% and sensitivity was 51% for diagnosis of breast carcinoma. CONCLUSION: Peripheral washout may be a reliable sign of malignancy on delayed contrast-enhanced MR images of the breast.

[Optimal use of MRI mammography from the economic viewpoint]. / Der optimale Einsatz der MR-Mammographie (MRM) unter wirtschaftlichen Gesichtspunkten.

With the introduction of the contrast agent gadolinum DTPA there were hopes that "MRM" would prove to be the investigatory technique that would largely solve the problems of breast diagnostics. However, after the early years of acceptance, the new method of investigation became a subject of controversy. Nonetheless, MRM today occupies a recognized place in diagnostics for certain indications. It is still true, however, that reliable use of this procedure requires a great deal of experience, since there is a relatively large area of overlap between benign and malignant tumors. Further, the costs are significantly higher than those for conventional methods of investigation. New studies that have been conducted at the Charité, Campus Virchow Medical Center in Berlin, suggest that, if one takes the relevant indications into account, MRM can be economic and contribute significantly to cost reduction. Application of a newly developed software package has shown that the good discrimination in a suspect area resulting from contrast agent enhancement makes possible a reliable differentiation between malignant and benign tissue changes. A further result was that, when certain boundary conditions are satisfied, a contrast agent bolus of 0.1 mmol/kg BW is sufficient, making a double dose (0.2 mmol/kg BW) unnecessary.

[Ultrasound detection of breast cancer with normal mammogram]. / Sonographischer Nachweis des Mammakarzinoms bei unauffälliger Mammographie.

In eleven patients with breast cancer the diagnosis was made by using ultrasound as the only method. In none of the patients could mammography show the malignoma. Although six of the patients underwent additional tube X-ray investigation, no radiological criteria of malignancy were found on the mammograms. In ten patients a lump of the breast was palpable and/or retraction of the skin was visible. In one woman, neither the clinical investigation nor the mammography could reveal the tumor. The ultrasound of the breast is a indispensable and useful method for diagnosing breast cancer.

Magnetic Resonance Female Breast Imaging (MRFBI) - Evaluation of the Changes in Signal Intensity over Time Pre- and Post-administration of 0.2 mmol/kg Gd-DTPA.

PURPOSE: We are looking for a threshold value to discriminate between benign and malign breast lesions in MRI of female breast after administration of 0.2 mmol Gadolinum-DTPA/kg bw. MATERIALS AND METHODS: Double coil breast MRI (1.5 Tesla) were performed in 65 patients with an suspicious lesion for malignancy in an anteriorly examination. 57 patients could be evaluated in our study design. Histopathological 35 patients had an invasive carcinoma, 3 patients had an in-situ-carcinoma and in 27 patients benign changes were found. RESULTS: For different carcinoma diameters we found a different increase of signal intensity (SI): small carcinoma (< 10 mm) had an maximum increase of SI of 102 %, medium sized (10 to 20 mm) 222 % and carcinomas over 20 mm showed an increase of 271 %. We did not find a significant difference between SI in benign and malign lesions. The sensitivity was 94.6 % the specificity 65 %. CONCLUSION: A threshold value to distinguish between malign and benign in MRI could not be defined. With the double normal Gd-DTPA dose we do not have better specificity and sensitivity than for normal dose (0.1 mmol/kg bw) is described.

Arterial switch procedure for D-transposition of the great arteries: quantitative midterm evaluation of hemodynamic changes with cine MR imaging and phase-shift velocity mapping-initial experience.

PURPOSE: To evaluate cine magnetic resonance (MR) imaging and phase-shift velocity mapping for assessment of the hemodynamic relevance of stenotic segments or specific hemodynamic changes in the great vessels after an arterial switch procedure for correction of D-transposition of the great arteries. MATERIALS AND METHODS: Twenty consecutive patients (age range, 2-17 years) with an acoustic window that was insufficient for Doppler transthoracic echocardiography were included in the study. Flow and diameter measurements of the pulmonary arterial trunk and its primary branches were performed with phase-shift velocity mapping and cine MR imaging. RESULTS: There were good correlations between pressure gradients in the pulmonary arteries estimated with MR imaging and those measured with Doppler echocardiography (r = 0.83, n = 15) and cardiac catheterization (r = 0.90, n = 13). Cine MR imaging revealed that the diameters of the right and left pulmonary arteries decreased with the expansion of the aorta during systole, which increased the peak velocity. This temporary stenosis was more severe in the right than in the left pulmonary artery and was accompanied by a significantly (P <.05) lower volume flow in the right artery. CONCLUSION: The anatomic situation after arterial switch repair tended to produce temporary stenoses in the primary pulmonary arterial branches, with significant changes in hemodynamics. These changes may affect the long-term outcome and go undetected with other imaging modalities.

Boeck sarcoidosis of the breast: mammographic, ultrasound, and MR findings.

The rare case of sarcoidosis of the breast is presented. The mammographic, ultrasound, and MR appearances are described.

International investigation of breast MRI: results of a multicentre study (11 sites) concerning diagnostic parameters for contrast-enhanced MRI based on 519 histopathologically correlated lesions.

A multicentre study was undertaken to provide fundamentals for improved standardization and optimized interpretation guidelines of dynamic contrast-enhanced MRI. Only patients scheduled for biopsy of a clinical or imaging abnormality were included. They underwent standardized dynamic MRI on Siemens 1.0 (163 valid lesions > or = 5 mm) or 1.5 T (395 valid lesions > or = 5 mm) using 3D fast low-angle shot (FLASH; 87 s) before and five times after standardized bolus of 0.2 mmol Gd-DTPA/kg. One-Tesla and 1.5 T data were analysed separately using a discriminant analysis. Only histologically correlated lesions entered the statistical evaluation. Histopathology and imaging were correlated in retrospect and in open. The best results were achieved by combining up to five wash-in or wash-out parameters. Different weighting of false-negative vs false-positive calls allowed formulation of a statistically based interpretation scheme yielding optimized rules for the highest possible sensitivity (specificity 30%), for moderate (50%) or high (64-71%) specificity. The sensitivities obtained at the above specificity levels were better at 1.0 T (98, 97, or 96%) than at 1.5 T (96, 93, 86%). Using a widely available standardized MR technique definition of statistically founded interpretation rules is possible. Choice of an optimum interpretation rule may vary with the clinical question. Prospective testing remains necessary. Differences of 1.0 and 1.5 T are not statistically significant but may be due to pulse sequences.