Monitoring of tumor burden in vivo by optical imaging in a xenograft SCID mouse model: evaluation of two fluorescent proteins of the GFP-superfamily.

BACKGROUND: Mouse models of human-malignant-melanoma (MM) are important tools to study tumor dynamics. The enhanced green fluorescent protein (EGFP) is widely used in molecular imaging approaches, together with optical scanners, and fluorescence imaging. PURPOSE: Currently, there are no data available as to whether other fluorescent proteins are more suitable. The goal of this preclinical study was to analyze two fluorescent proteins of the GFP superfamily under real-time in vivo conditions using fluorescence reflectance imaging (FRI). MATERIAL AND METHODS: The human melanoma cell line MeWo was stable transfected with one plasmid: pEGFP-C1 or pDsRed1-N1. We investigated two severe combined immunodeficiency (SCID)-mice groups: A (solid xenografts) and B (xenografts as metastases). After three weeks, the animals were weekly imaged by FRI. Afterwards the mice were euthanized and metastases were imaged in situ: to quantify the cutis-dependent reduction of emitted light, we compared signal intensities obtained by metastases in vivo with signal intensities obtained by in situ liver parenchyma preparations. RESULTS: More than 90% of cells were stable transfected. EGFP-/DsRed-xenograft tumors had identical growth kinetics. In vivo the emitted light by DsRed tumors/metastases was much brighter than by EGFP. DsRed metastases were earlier (3 vs. 5 weeks) and much more sensitive detectable than EGFP metastases. Cutis-dependent reduction of emitted light was greater in EGFP than in DsRed mice (tenfold). Autofluorescence of DsRed was lower than of EGFP. CONCLUSION: We established an in vivo xenograft mouse model (DsRed-MeWo) that is reliable, reproducible, and superior to the EGFP model as a preclinical tool to study innovative therapies by FRI under real-time in vivo conditions.

Intravenous Iodinated Contrast Agents Amplify DNA Radiation Damage at CT.

PURPOSE: To determine the effect of the use of iodinated contrast agents on the formation of DNA double-strand breaks during chest computed tomography (CT). MATERIALS AND METHODS: This study was approved by the institutional review board, and written informed consent was obtained from all patients. This single-center study was performed at a university hospital. A total of 179 patients underwent contrast material-enhanced CT, and 66 patients underwent unenhanced CT. Blood samples were taken from these patients prior to and immediately after CT. In these blood samples, the average number of phosphorylated histone H2AX (γH2AX) foci per lymphocyte was determined with fluorescence microscopy. Significant differences between the number of foci that developed in both the presence and the absence of the contrast agent were tested by using an independent sample t test. RESULTS: γH2AX foci levels were increased in both groups after CT. Patients who underwent contrast-enhanced CT had an increased amount of DNA radiation damage (mean increase ± standard error of the mean, 0.056 foci per cell ± 0.009). This increase was 107% ± 19 higher than that in patients who underwent unenhanced CT (mean increase, 0.027 foci per cell ± 0.014). CONCLUSION: The application of iodinated contrast agents during diagnostic x-ray procedures, such as chest CT, leads to a clear increase in the level of radiation-induced DNA damage as assessed with γH2AX foci formation.

Influence of different iodinated contrast media on the induction of DNA double-strand breaks after in vitro X-ray irradiation.

The objective of this work was to examine differences in DNA double-strand break induction in peripheral blood lymphocytes after in vitro X-ray irradiation between iodinated contrast agents. Four different iodinated X-ray contrast agents--three of them with two different iodine concentrations--and mannitol (negative control; concentration of 150 mg mannitol per ml blood) were pipetted into blood samples so that there was a concentration of 0, 7.5 or 15 mg of iodine per ml blood in the samples. Negative controls without contrast medium (0 mg of iodine per ml blood) were also processed for every irradiation dose. The tubes were exposed to 0, 20 or 500 mGy in vitro X-ray irradiation. After that, the lymphocytes were separated by using density-gradient centrifugation. Fluorescence microscopy was applied to determine the average number of γH2AX-foci per lymphocyte in the presence or absence of different contrast media or mannitol. Differences in the number of γH2AX-foci were statistically analysed by one-way ANOVA and post-hoc Tukey's honestly significant difference test. Iodinated contrast agents led to a statistically significant increase in DNA double-strand breaks after in vitro irradiation. This effect increased statistically significant with rising radiation dose and appeared independent of the contrast agent used (iopromid, iodixanol, iomeprol, iopamidol). A statistically significant difference in DNA damage between the different tested contrast agents was not found. Therefore, the increase in DNA double-strand breaks depends solely on the amount of iodine applied. For evaluation of clinical consequences, our findings could be tested in further animal studies.

Classification of acute and delayed contrast media-induced reactions: proposal of a three-step system.

Physicians and scientists use a broad spectrum of terms to classify contrast media (CM)-induced adverse reactions. In particular, the designation of hypersensitivity reactions is quite varied. Consequently, comparisons of different papers dealing with this subject are difficult or even impossible. Moreover, general descriptions may lead to problems in understanding reactions in patients with a history of adverse CM-reactions, and in efficiently managing these patients. Therefore, the goal of this paper is to suggest an easy system to clearly classify these reactions. The proposed three-step systems (3SS) is built up as follows: step 1 exactly describes the clinical features, including their severity; step 2 categorizes the time point of the onset (immediate or nonimmediate); and step 3 generally classifies the reaction (hypersensitivity or nonhypersensitivity reaction). The 3SS may facilitate better understanding of the clinical manifestations of adverse CM reactions and may support the prevention of these reactions on the basis of personalized medicine approaches.

Increased end diastolic wall stress precedes left ventricular hypertrophy in dilative heart failure--use of the volume-based wall stress index.

INTRODUCTION: To examine a potential interrelation of left ventricular (LV) wall stress and hypertrophy, we assessed increased wall stress in patients with suspected non-ischemic dilative cardiomyopathy and addressed the question whether increased LV wall stress is involved in the development of LV hypertrophy. METHODS: We studied 502 consecutive patients in whom LV mass, LV enddiastolic (LVEDV) and endsystolic volume (LVESV) was determined using cardiac magnetic resonance (CMR). Based on a thick-walled sphere, we introduced a myocardial and cavity volume-based wall stress index. Follow up CMR examinations were obtained in a representative subgroup of 71 patients. RESULTS: LV mass was correlated with LVEDV (r=0.517, P<0.001) and LVESV (r=0.510, P<0.001). Despite LV hypertrophy, LV mass was not sufficient to compensate for LV dilatation resulting in an increased wall stress. Increased LV enddiastolic wall stress was found in 227 patients (45 %) and increased endsystolic wall stress in 198 (39 %). In patients with normal LV enddiastolic wall stress ≤ 4 kPa at time of enrolment, no changes of LV mass occurred during follow up (142 ± 46 g vs. 141 ± 47 g). In contrast, patients with initially increased LV enddiastolic wall stress >4 kPa developed greater LV hypertrophy (141 ± 48 g vs. 158 ± 60 g, P=0.0247). CONCLUSIONS: LV wall stress can be derived from CMR measurements of LV myocardium and cavity using the volume-based wall stress index. Increased LV enddiastolic wall stress leads to LV hypertrophy. Beyond a certain degree of LV dilatation, the extent of hypertrophy does not compensate LV dilatation. The ensuing increased wall stress promotes dilatation and consecutively hypertrophy with an unfavorable prognosis. It is proposed to use the volume-based wall stress index as new diagnostic criterion in heart failure.

Diagnostic accuracy of magnetic resonance imaging: a prospective evaluation of patients with suspected appendicitis (diamond).

PURPOSE: To show the effect of standard magnetic resonance imaging (MRI) in patients with suspected appendicitis on negative laparotomy and perforation rate. Moreover, the economic impact on hospital resources was evaluated. MATERIALS AND METHODS: In all, 52 patients (21 female; mean age 44.7 years) were prospectively included in this Institutional Review Board (IRB)-approved study. Abdominal MRI including coronal inversion recovery, axial T2-weighted, and contrast-enhanced axial T1-weighted sequences was performed. MRI results were compared to final clinical outcome determined by follow-up or histopathology. Change of treatment was evaluated according to the final clinical outcome. Economic impact was evaluated by comparing the costs of MRI to the savings due to a change in treatment after MRI. Negative laparotomy and perforation rate as well as sensitivity and specificity were derived. RESULTS: Negative laparotomy and perforation rate were 0% (0/52) and 8% (1/13). Sensitivity and specificity for detecting acute appendicitis were 85% (11/13) and 97% (38/39). In 40% of patients therapy changed due to the MRI. The overall effect on the use of hospital resources was a net saving of €2,335. CONCLUSION: Abdominal MRI in the evaluation of patients with suspected appendicitis and equivocal clinical findings is safe, reliable, and cost-effective. It should be considered an important alternative to computed tomography.

The presence of iodinated contrast agents amplifies DNA radiation damage in computed tomography.

The purpose of this study was to determine the influence of iodinated contrast agents on the formation of DNA double-strand breaks in vitro in lymphocytes and to verify these results in patients undergoing diagnostic computed tomography examinations. Blood samples were irradiated in vitro in the presence of iodinated X-ray contrast agent. Controls were irradiated without contrast agent. Fourteen patients were investigated using contrast-enhanced computed tomography (CT), and 14 other patients with unenhanced CT. Blood samples were taken prior to and 5 min and 1, 2 and 24 h after the CT examination. In these blood samples the average number of γH2Ax-foci per lymphocyte was enumerated by fluorescence microscopy. Statistical differences between foci numbers developed in the presence and absence of contrast agent were tested using an independent sample t-test. In vitro foci numbers after irradiation were significantly higher when contrast agent was present during irradiation. In vivo, γH2Ax-foci levels were 58% higher in patients undergoing contrast-enhanced CT compared with those undergoing unenhanced CT. In the presence of iodinated contrast agents DNA, damage is increased and the radiation dose is not the only factor affecting the amount of DNA damage. Individual patient characteristics and biological dosimetry applications, e.g. the analysis of γH2Ax-foci, have to be considered.

Occurrence of late gadolinium enhancement is associated with increased left ventricular wall stress and mass in patients with non-ischaemic dilated cardiomyopathy.

AIMS: Occurrence of late gadolinium enhancement (LGE) as assessed by cardiac magnetic resonance (CMR) imaging has been attributed to various myocardial injuries. We hypothesized that LGE is associated with left ventricular (LV) wall stress. METHODS AND RESULTS: We examined 300 patients with suspected non-ischaemic dilated cardiomyopathy. Cardiac magnetic resonance was used to assess LV volume, mass, wall stress, and LGE. Increased LV end-diastolic wall stress (> 4 kPa) was found in 112 patients (37 %), and increased end-systolic wall stress (>18 kPa) in 121 patients (40%). Presence of LGE was observed in 93 patients (31%). End-diastolic (94 ± 43 vs. 79 ± 42 ml/m(2), P = 0.006) and end-systolic LV volumes (62 ± 44 vs. 44 ± 37 ml/m(2), P < 0.001) and LV mass (95 ± 34 vs. 78 ± 31 g/m(2), P < 0.001) were increased in patients exhibiting LGE. In particular, LV end-diastolic and end-systolic wall stress were increased (4.5 ± 2.8 vs. 3.6 ± 3.0 kPa, P = 0.025; 19.6 ± 9.1 vs. 17.5 ± 8.2 kPa, P = 0.045). Late gadolinium enhancement was observed more frequently than would be expected from random occurrence in patients with increased end-diastolic (39 vs. 26%, P = 0.020) and end-systolic wall stress (41 vs. 24%, P = 0.002). Both normal end-diastolic and end-systolic wall stress had a high negative predictive value for LGE (75 and 76%). CONCLUSIONS: The present study shows that occurrence of LGE in cardiomyopathy is associated with increased LV wall stress and mass. Suspected causes are an increased capillary leakage by stretch, impaired contrast agent redistribution, or increased diffusion distances. It is proposed that LGE should be considered as a potential prognostic determinant of heart failure and severe arrhythmias.

A 20-channel receive-only mouse array coil for a 3 T clinical MRI system.

A 20-channel phased-array coil for MRI of mice has been designed, constructed, and validated with bench measurements and high-resolution accelerated imaging. The technical challenges of designing a small, high density array have been overcome using individual small-diameter coil elements arranged on a cylinder in a hexagonal overlapping design with adjacent low impedance preamplifiers to further decouple the array elements. Signal-to-noise ratio (SNR) and noise amplification in accelerated imaging were simulated and quantitatively evaluated in phantoms and in vivo mouse images. Comparison between the 20-channel mouse array and a length-matched quadrature driven small animal birdcage coil showed an SNR increase at the periphery and in the center of the phantom of 3- and 1.3-fold, respectively. Comparison with a shorter but SNR-optimized birdcage coil (aspect ratio 1:1 and only half mouse coverage) showed an SNR gain of twofold at the edge of the phantom and similar SNR in the center. G-factor measurements indicate that the coil is well suited to acquire highly accelerated images.

Association of hyperhomocysteinemia with left ventricular dilatation and mass in human heart.

BACKGROUND: Hyperhomocysteinemia is a risk factor for ischemic heart disease. Several other mechanisms apply also to dilative types of heart failure of various, non-ischemic etiologies. We hypothesized that hyperhomocysteinemia is associated with left ventricular (LV) dilatation and hypertrophy in dilative cardiomyopathy. METHODS: Homocysteine was measured in 66 individuals with suspected cardiomyopathy. Cardiac magnetic resonance imaging was used to assess LV volume, mass, and wall stress. RESULTS: Hyperhomocysteinemia (> 12 micromol/L) was found in 45 patients (68%). LV mass was greater in these patients compared with individuals with normal homocysteine (83+/-27 vs. 67+/-19 g/m(2); p<0.02). Homocysteine was increased in patients with increased brain natriuretic peptide > or = 100 pg/mL (18.3+/-5.9 vs. 14.9+/-5.1 micromol/L; p=0.018). LV mass, LV end-diastolic and end-systolic volume (LVEDV, LVESV) were significantly increased in individuals in the upper quartile compared with the lower quartile (90+/-25 vs. 65+/-18 g/m(2), p=0.021; 114+/-50 vs. 71+/-23 mL/m(2), p=0.042; 76+/-51 vs. 36+/-22 mL/m(2), p=0.045). LV dilatation (LVEDV > or = 90 mL/m(2)) was more common in hyperhomocysteinemia (> 12 micromol/L, p=0.0166). Normalized LV mass was correlated with homocysteine (r=0.346, p=0.065). Homocysteine was not significantly correlated with LVEDV (r=0.229, p=0.065), LV end-diastolic wall stress (r=0.226, p=0.069) and LV ejection fraction. CONCLUSIONS: Hyperhomocysteinemia appears to be, at least in part, involved in a disproportional LV dilatation, where the ensuing hypertrophy is not sufficient to compensate for the increased wall stress. A potential mechanism is the hyperhomocysteinemia associated increase in oxidative stress that favors muscle fiber slippage.

MR imaging for acute lower abdominal and pelvic pain.

Acute lower abdominal and pelvic pain is a frequent complaint of patients in the emergency room. Usually, the condition of these patients is assessed with computed tomography (CT) and ultrasonography (US). However, the need to reduce radiation doses of as much as 20 mSv at CT, especially in younger patients and possibly pregnant patients, and the operator dependence of US have led to an increased use of magnetic resonance (MR) imaging to assess those patients. MR imaging shows high accuracy in these patients and can be used to establish an accurate diagnosis quickly and reliably. A short imaging protocol of about 10 minutes, without the use of an intravenous contrast agent in most cases, allows investigation of these patients. The basic imaging protocol that localizes the diseased anatomic region needs to be complemented by focused anatomic imaging of the diseased area. Although MR imaging might not be the modality of choice for all patients, it may be beneficial for a subset of patients for whom CT is not warranted (pregnant patients or young patients) and US findings are inconclusive. In patients with acute abdominal and pelvic pain, the range of diseases and disorders that can be diagnosed with MR imaging is extremely broad. Therefore, MR imaging should be considered as an excellent imaging modality for the evaluation of these patients.

Depression of heart rate variability in patients with increased ventricular wall stress.

BACKGROUND: Heart failure is characterized by neurohumoral dysfunction that can be assessed by measurement of heart rate variability (HRV). Depression of HRV is related to several hemodynamic parameters. We hypothesized that an increased left ventricular (LV) wall stress is related to a depressed HRV in patients with LV dilatation or dysfunction. METHODS: Cardiac function and mass were measured in 31 patients with LV dilatation or dysfunction and 21 controls using cardiac magnetic resonance (CMR) imaging. LV wall stress was calculated using a CMR-based thick-walled sphere model. Standard deviation of normal-to-normal (NN) intervals (SDNN) and average NN intervals over 5 minutes (SDANN-i) were calculated. RESULTS: LV end-diastolic (ED) and end-systolic (ES) wall stress were significantly increased in patients with SDNN < 75 ms (P < 0.05). SDNN and SDANN-i were decreased (P = 0.001, P < 0.001) in patients with LVED wall stress >8 kPa and LVES wall stress >30 kPa (P < 0.05). To examine potential effects of LVEF, LVED and LVES volume, and wall stress on HRV, a multiple linear regression analysis was performed, which revealed LVED wall stress as the only independent parameter influencing SDNN (P = 0.039). LV ejection fraction, LV mass, and volumes were not significantly related to HRV. CONCLUSIONS: LV wall stress was independently related with depression of HRV. Therefore, LV wall stress might be prognostically important and a therapeutic target in heart failure.

Prospective evaluation of the diagnostic accuracy of secretin-enhanced magnetic resonance cholangiopancreaticography in suspected chronic pancreatitis.

The purpose of this study was to determine the improvement in sensitivity and specificity of magnetic resonance cholangiopancreaticography (MRCP) in the diagnosis of chronic pancreatitis due to the application of secretin. Sixty-two consecutive patients with suspected chronic pancreatitis were prospectively included in our study. All investigations were carried out in a clinical 1.0-T MR-scanner using heavily T2-weighted pre- and dynamic post secretin measurements. Dynamic images were acquired every 30 s for a total imaging time of 10 min. Two experienced radiologists blinded for all other results evaluated the images in random order in two sessions: one for the native images and one for the stimulated MRCP series. The gold standard for the final diagnosis was the summary of all clinical and radiological results. Sensitivity and specificity for the diagnosis of chronic pancreatitis and the kappa coefficient for the agreement between both observers were calculated. Prior to secretin application, investigators achieved sensitivities of 78% and 56%, respectively, and specificities of 89% and 96%, respectively. After secretin application, the sensitivity for the first observer remained at 78%; for the second observer it increased to 67%, whereas specificities improved to 94% and 98%, respectively. Following secretin application, agreement determined between the two investigators improved from 0.73 to 0.84. While MRCP already provides high sensitivity and specificity, application of secretin increases both values and the reliability of the diagnosis further.

Prospective evaluation of the value of magnetic resonance imaging in suspected acute sigmoid diverticulitis.

PURPOSE: The purpose of this study was to prospectively investigate patients with suspected acute colonic diverticulitis and to provide sensitivity, specificity, and interobserver agreement in a blinded trial. METHODS: Fifty-five patients (29 men; 59 +/- 13 (range, 29-76) years) who reported to the emergency room with clinically suspected acute colonic diverticulitis were prospectively included in the study. All patients underwent magnetic resonance imaging scans of their abdomen before and after contrast agent administration. Two assessors blinded to all clinical, laboratory, and radiologic results evaluated the images separately. RESULTS: The assessors reported colonic wall thickening, segmental narrowing of the colon, presence of diverticula, pericolic fatty infiltration, ascites, and abscesses. The assessors had to diagnose or rule out acute colonic diverticulitis. Sensitivities, specificities, positive, and negative likelihood ratios were derived. To determine interobserver agreement, a Cohen's kappa coefficient was calculated. The two assessors exhibited sensitivities of more than 94 percent, specificities of 88 percent, positive likelihood ratios of more than 7.5, and negative likelihood ratios of less than 0.07. The kappa coefficient showed a significant, strong correlation between both assessors (kappa = 0.68). CONCLUSIONS: Magnetic resonance imaging is investigator independent and provides high sensitivity and specificity for the diagnosis of acute colonic diverticulitis.

Relationship between pulmonary artery volumes at computed tomography and pulmonary artery pressures in patients with- and without pulmonary hypertension.

OBJECTIVES: This study was designed to determine the relationship between pulmonary artery (PA) volumes at computed tomography (CT) and PA pressures at right-sided heart catheterization in patients with and without pulmonary hypertension (PAH) to develop a noninvasive CT method of PA pressure quantification. MATERIALS AND METHODS: Sixteen patients with chronic sleep apnea syndrome underwent contrast enhanced helical CT (slice thickness 3mm; pitch 2; increment 2mm) at inspiration. Eight patients had PAH while cardiopulmonary disease has been excluded in eight other patients. Vascular volumes were determined using a 3D technique (threshold seeded vascular tracing algorithm; thresholds -600 H [lower] and 3,000 H [upper]). Right-sided heart catheterization measurements were available for linear regression analysis of PA volumes and pressures. RESULTS: Correlation between PA pressures and volumes (normalized for BMI), was high in both groups (without PAH: r=.85; with PAH .90, Pearson). Compared to elevated PA pressures in patients with pulmonary hypertension (p<.005), PA volumes also were significantly increased (p<.05) among the groups. CONCLUSIONS: High correlation was found between PA volumes and mean PA pressures in patients with- and without PAH. Significant differences in PA volumes at CT-volumetry may admit non-invasive determination of pulmonary hypertension.

Deregulation of tumor angiogenesis and blockade of tumor growth in PPARbeta-deficient mice.

The peroxisome proliferator-activated receptor-beta (PPARbeta) has been implicated in tumorigenesis, but its precise role remains unclear. Here, we show that the growth of syngeneic Pparb wild-type tumors is impaired in Pparb(-/-) mice, concomitant with a diminished blood flow and an abundance of hyperplastic microvascular structures. Matrigel plugs containing pro-angiogenic growth factors harbor increased numbers of morphologically immature, proliferating endothelial cells in Pparb(-/-) mice, and retroviral transduction of Pparb triggers microvessel maturation. We have identified the Cdkn1c gene encoding the cell cycle inhibitor p57(Kip2) as a PPARbeta target gene and a mediator of the PPARbeta-mediated inhibition of cell proliferation, which provides a possible mechanistic explanation for the observed tumor endothelial hyperplasia and deregulation of tumor angiogenesis in Pparb(-/-) mice. Our data point to an unexpected essential role for PPARbeta in constraining tumor endothelial cell proliferation to allow for the formation of functional tumor microvessels.

The impact of the dosage of intravenous gadolinium-chelates on the vascular signal intensity in MR angiography.

To show the effects of different concentrations of contrast agent on signal time curves and image contrast of abdominal aorta, vena cava and portal vein in comparison to each other as well as liver and spleen. Imaging was carried out in a 1.0 Tesla clinical scanner. Sixty patients were prospectively included and divided into three contrast agent (Gd-DTPA) dosage groups (0.1 mmol/kg, 0.2 mmol/kg and 0.3 mmol/kg). All patients were scanned using a time-resolved 3D FLASH sequence (58 phases) with a 3.75 second acquisition time per phase. Signal time curves and image contrast levels were evaluated. No significant differences were found for the maximum signal enhancement between the groups in the investigated vessels. Image masking, the subtraction of the baseline images, resulted in a substantial improvement in image contrast. However, statistically significant differences between the contrast agent dosage groups could only be found for vena cava and liver. Vessel conspicuity is not significantly improved with an increase of contrast agent dose. However, an increase in contrast agent dosage increases vessel contrast. Our findings suggest that a single dose single station investigation seems to be sufficient for high quality abdominal MRA.

How to successfully implement E-learning for both students and teachers.

RATIONALE AND OBJECTIVES: Electronic learning (e-learning) may provide a means to enhance learning efficacy. However, introduction of e-learning often fails. We describe a strategy of how an e-learning curriculum was successfully implemented. MATERIALS AND METHODS: The curriculum was designed based on published evidence. It consists of self-directed learning, an online discussion forum, and discussion rounds. The e-content in nuclear medicine and radiotherapy was produced by the k-MED team of medical authors, web designers, and psychologists. The online courses were delivered via a dedicated learning management system. The e-content for diagnostic radiology and physics was provided as PDF/HTML script by the respective teachers who objected to participate in the k-MED project. The exam was taken online. Online evaluation of the curriculum by the students was taken at the end of the course. RESULTS: The new curriculum proved very effective. The time for the preparation for the clinical part of the radiology course could be reduced from 4 to 2 weeks. The students particularly enjoyed the self-directed learning. Although the material provided by k-MED received 90%-99% positive scores, the HTML and PDF scripts scored worse (13%-67% positive ratings). The positive results of the evaluation convinced the teachers responsible for physics and diagnostic radiology to participate in k-MED. CONCLUSIONS: As our example shows, new e-learning curricula can successfully be introduced. The strategy of implementation should be based on the existing evidence from the literature. The new curriculum helped to increase the efficacy of teaching and save time as the duration of the respective part of the course could be reduced by half.

Right ventricular cardiac myxoma. Diagnostic usefulness of cardiac magnetic resonance imaging.

BACKGROUND: Cardiac myxomas are the most common type of cardiac tumors. About 75-85% of cardiac myxomas originate in the left atrium, 15-20% in the right atrium. Most myxomas arise from the interatrial septum adjacent to the fossa ovalis. Only 3-4% are found in the left and right ventricle each. Although myxomas are histologically benign, they may be fatal because of their strategic position. CASE STUDY: The authors report on a 24-year-old patient with stabbing thoracic pain and dyspnea due to pulmonary thromboembolism that was caused by an atypically localized myxoma at the right ventricular apex originating from the interventricular septum. The diagnosis was based on cardiac magnetic resonance (CMR) imaging. Superior to echocardiography, CMR could strengthen the diagnostic accuracy by additional information on tissue characterization using different imaging sequences. Typically for cardiac myxomas, contrast enhancement was moderate and delayed enhancement was found in the outer circumferential tumor margins only. CONCLUSION: High spatial resolution and multiplane imaging combined with different acquisition patterns of CMR achieve a global view of the heart that seems to be useful for diagnosing cardiac tumorous masses.