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Biomedical subjects

U Mödder

Publications and source records attributed to U Mödder.

At least 37 records · Page 2Linked to original sources
PubMed2004

Exclusion of brain lesions: is MR contrast medium required after a negative fluid-attenuated inversion recovery sequence?

We hypothesized that in patients with negative fluid-attenuated inversion recovery (FLAIR) images T(2) weighted fast spin-echo (FSE) images and T(1) weighted spin-echo (SE) images before and after intravenous administration of gadolinium-based contrast medium display no pathology either. Thus, we assessed the negative predictive value of FLAIR images to rule out MR-detectable brain lesions. 1026 consecutive cranial MR examinations were reviewed. Routine MRI of the brain included T(1) weighted coronal imaging before and after administration of gadopentetate dimeglumine, axial T(2) weighted FSE and fast-FLAIR imaging. The FLAIR images were rated by two radiologists into categories of 0 (without pathologic changes) and 1 (with pathologic changes). Two other radiologists analysed the complete examination. In 284 MR examinations of the brain no abnormalities were found (28%). FLAIR-ratings were false-negative in four cases and false-positive in 30 cases. Sensitivity and specificity of the FLAIR sequence for MR-detectable brain lesions were 99.5% and 89.4%. The unselective application of gadolinium avoided one false-negative MR-reading and improved the sensitivity of the MR-examination from 99.5% to 99.6%. Positive and negative predictive values were 96.1% and 98.4%, respectively. The interobserver reliability was kappa=0.93 for the FLAIR-readers and 0.89 for the readers who rated the complete examination. In conclusion, negative FLAIR images provide a high negative predictive value for MR-detectable brain lesions. Thus, in patients with negative FLAIR images the unselective application of gadolinium seems to be unnecessary.

Adolescent↗
PubMed2003

Lack of portosystemic bacterial translocation in patients with liver cirrhosis after placement of transjugular shunt.

The purpose of this study was to clarify whether bacteria are transferred from the portal venous system into central venous blood during the placement of a transjugular portosystemic stent shunt (TIPSS). TIPSS was created in 30 consecutive cirrhotic patients for recurrent variceal bleeding ( n=12), refractory ascites ( n=16), or hepatorenal syndrome ( n=2). Microbiological analysis was performed prospectively on central venous blood before and on portal venous blood immediately after puncture of the portal vein. Twenty minutes after the placement of TIPSS, another sample of central venous blood was obtained. None of the first two sets of blood cultures showed bacterial growth, so that no bacterial transfer was seen at the time of TIPSS placement. Four of the third sets of blood samples showed skin and mouth flora, interpreted as iatrogenic contamination.

Adult↗
PubMed2003

[Predictive parameters of infectiologic complications in patients after TIPSS].

AIM: To define predictive parameters of a complicated clinical course after the TIPSS procedure. METHODS: Blood cultures were drawn prospectively in 41 patients from a central line and from the portal venous blood before stent placement as well as from the central line 20 min after intervention. C-reactive protein (CRP) (mg/dl) and white blood cell count (WBC,/microl) on the day of TIPSS-procedure (d0), the first (d1) and seven (d7) days after TIPSS were compared in patients with a complicated clinical course (spontaneous bacterial peritonitis,pneumonia,sepsis; group I) to patients without clinical complications (group II) RESULTS: Group I showed a significant increase in CRP (d0: 1.8+/-1.0; d1: 3.2+/-1.5; d7: 4.3+/-3.2), and white blood cell count (d0: 7700+/-2600; d1: 10800+/-2800; d7: 7500+/-1800) on the first day after TIPSS-procedure in comparison to group II (CRP: d0: 1.6+/-0.6; d1: 1.8+/-1.0; d7: 1.9+/-0.6. WBC: d0: 6900+/-1500; d1: 8000+/-1600; d7: 7600+/-1400). Microbiological analysis showed in 12% skin or oral flora in the last sample. CONCLUSIONS: The course of CRP and WBC-count during the first week after TIPSS procedure may indicate patients with a potential risk of a complicated clinical course.

Adult↗
PubMed2003

Carotid surgery in acute symptomatic patients.

OBJECTIVES: evaluation of urgent carotid artery surgery with new diagnostic techniques and changing surgical considerations at a university hospital. DESIGN, MATERIAL AND METHODS: prospective monitoring and assessment of outcome in 67 patients who underwent urgent carotid surgery because of symptomatic extracranial carotid artery involvement. Patients were examined via the stroke unit: duplex sonography was mandatory for diagnosis of extracranial carotid artery disease, as was proof of an open middle cerebral artery (MCA). Assessment of intracerebral damage followed CT or MR imaging procedures. Perioperative and surgical management was standardized. Neurological impairment was assessed pre-, postoperatively and at follow-up using the Rankin scale. "Urgent" was defined as "immediate" after the final diagnostic step had been performed. RESULTS: within a period of 26 months 67 symptomatic patients (58% stroke, 42% TIA) underwent urgent carotid surgery. Median time from admission to surgery was 2 days. In all but five cases flow through the ICA could technically be restored (93%). Thirty-day mortality was 3% and disease-related morbidity 13%. The one and two year survival rates were 92 and 90%, respectively. No ipsilateral recurrent stroke occurred during follow-up. CONCLUSIONS: clinical decision-making based on stratified diagnostic workup by means of extra- and intracranial as well as intracerebral hemodynamics using new imaging techniques may select patients who will benefit more from urgent surgery than from conservative management.

Acute Disease↗
PubMed2002

Vertebral fractures in multiple myeloma: first results of assessment of fracture risk using dynamic contrast-enhanced magnetic resonance imaging.

The objective of this study was to evaluate dynamic contrast-enhanced magnetic resonance imaging (d-MRI) as a prognostic indicator of lumbar vertebral fractures in patients with multiple myeloma. d-MRI of the lumbar spine was performed in ten patients with multiple myeloma. A fast gradient echo sequence (turbo fast low-angle shot, two-dimensional) was used, together with controlled bolus injection of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA). The maximum increase in signal intensity [amplitude (A),arbitrary units (a.u.)] was assessed for each lumbar vertebra. About half a year later (median: 6.2 months) magnetic resonance imaging was repeated to detect new fractures. Amplitudes of vertebrae which fractured after the initial d-MRI were compared with amplitudes of vertebrae which did not fracture during follow-up. Six of ten patients (7 of 50 lumbar vertebrae) showed new fractures. Five patients fractured one vertebra each, whereas one patient had several vertebrae involved. The initial d-MRI showed significantly higher amplitudes (p<0.0001) in those vertebrae that subsequently fractured (A: 33.1+/-8.1 vs 16.7+/-4.2). On retrospective analysis, a cutoff level of 25 a.u. discriminated without overlap between vertebrae that fractured during follow-up and those which did not. The maximum increase in signal intensity (the amplitude) on d-MRI appears to be a prognostic marker capable of predicting vertebral fractures of the lumbar spine in patients with multiple myeloma. d-MRI may therefore be helpful in identifying patients who might benefit from localized radiation therapy or surgical intervention.

Adult↗
PubMed2002

Quantification of total abdominal fat volumes using magnetic resonance imaging.

The purpose of this study was to develop a rapid and reliable method for the measurement of total abdominal fat volumes in diabetic patients using magnetic resonance imaging (MRI). Total volume coverage of the abdomen was obtained using T1-weighted images in 37 diabetic patients (age 48 +/- 13 y mean +/-SD). Quantification of intraabdominal (IAF), subcutaneous (SCF), and total abdominal fat volumes (TAF) was performed using a semiautomated computer assisted analysis. The variability of image analysis for fat measurements between two observers and within observers was assessed. Mean volumes (+/- SD) for IAF, SCF and TAF were 10.5 l (+/- 5.0 l), 15.1 l (+/-7.3 l) and 25.7 l (+/-11.5 l), respectively. Reliability of measurements was excellent for both observers (observer I: intraobserver reliability IAF, SCF and TAF: r = 0.999, r = 0.999 r = 1.0, observer II: r = 0.999, r = 0.999 and r = 1.0), as well as between both observers (interobserver reliability IAF, SCF, and TAF: r = 0.999, r = 0.999, r = 1.0). A single computer analysis required about 9 min in addition to 7 min scan time. The developed analysis method of MR images allows a rapid and reliable determination of total intraabdominal, subcutaneous and total fat volumes. This method has the potential to be very valuable in respective studies in patients with diabetes.

Abdomen↗
PubMed2002

[Dynamic contrast-enhanced MRI for evaluating bone marrow microcirculation in malignant hematological diseases before and after thalidomide therapy].

PURPOSE: The aim of the study was to measure microcirculation parameters by dynamic contrast-enhanced MRI (d-MRI) and to evaluate the anti-angiogentic effects during treatment with thalidomide in different hematologic malignancies. METHODS: In 20 healthy normal persons, 20 patients with myelodysplastic syndromes (MDS), 10 patients with multiple myeloma (MM) and 10 with myelofibrosis (MF) a fast gradient echo sequence (Turbo fast low angle shot 2D) with a pump controlled bolus infusion of gadolinium-DTPA was performed before and in 18 of these after beginning (average of 4.3 months) of a thalidomide therapy. Two pharmacokinetic parameters--the amplitude and exchange-rate-constant--were calculated and a statistical comparison of these values between healthy persons and patients as well as a correlation with the clinical course was executed. RESULTS: Compared with the normal controls the patients showed a higher amplitude (normal persons 14.4 +/- 5.2, MDS 24.8 +/- 8.1, MF 35.9 +/- 4.3, MM 23.4 +/- 3.6) and exchange-rate-constant (normal persons 0.124 +/- 0.042, MDS 0.136 +/- 0.036, MF 0.144 +/- 0.068, MM 0.131 +/- 0.034). In the d-MRI-follow-up examinations a significant (p < 0.005) reduction of the amplitude and exchange rate constant values was evident in 14 of 18 patients undergoing a thalidomide therapy. Clinically all of these patients showed a therapy responding with complete or partial diseases remission. CONCLUSIONS: In patients with hematologic malignancies significantly higher d-MRI-microcirculation parameters of the lumbar spine can be demonstrated than in normal persons. During anti-angiogenetic treatment with thalidomide a decrease of these values was observed in case of a responding to therapy.

Adult↗
PubMed2002

[Imaging of supradiaphragmatic manifestations of extranodal non-Hodgkin's lymphoma].

Malignant lymphomas are differentiated into Hodgkin's and non-Hodgkin's-lymphoma (NHL). The following article discusses the imaging of extranodal NHL in supradiaphragmatic localizations. Lymphoma can affect nearly all tissues, and represent a rare entity as primary extranodal NHL. A secondary involvement of non-nodal tissue as consequence of a generalized lymphoproliferative disease is more common,and may be seen as well in HIV-positive patients defining AIDS. As extranodal lymphoma mimic the radiologic appearance of other malignant tumors, direct diagnosis without histologic analysis is often impossible. The article describes typical manifestations of lymphoma of the lungs, the head and neck area including the large glands, and rare localizations as the heart or the breast.

Head and Neck Neoplasms↗
PubMed2002

[Modern diagnostic imaging: MR urography].

MR-urography presents a new diagnostic approach to the urinary system, resulting in images comparable to those known from i.v.-urography. T2-weighted MR-urograms demonstrate static fluid without ionizing radiation or nephrotoxic contrast media. The excretory renal function can be examined by the use of gadolinium-enhanced T1-urography. The degree and cause of ureteric obstruction can be diagnosed with high sensitivity and specificity. On the other hand, urolithiasis is frequently misdiagnosed by MR-urography and, in this case, spiral CT should be used. Pediatric or pregnant patients can be examined as well as donors before and patients after renal transplantation. Furthermore, in case of a tumor MR-imaging, including MR-angiography, is a potential diagnostic "all-in-one" approach.

Adult↗
PubMed2002

[Sensitivity and significance of nuclear magnetic tomography findings of finger joints in rheumatoid arthritis].

Evaluation of the sensitivity and value of magnetic resonance imaging (MRI) findings and miniarthroscopic investigations (mini-/needle-arthroscopy = MA) of metacarpophalangeal (MCP) joints in patients with rheumatoid arthritis (RA). 30 patients with RA (21 female, 9 male), disease duration 2 months to 22 years and mean disease activity score (DAS) of 3.90 (range: 2.00-7.67) were examined by MRI of the hand (MCP region) and following MA of the MCP-II joints. MRI parameters for arthritis (synovial enhancement, synovial extension, cortical alterations, joint gap width) and corresponding macroscopic items (synovial extension, synovial hyperemia and vascularity, cortical alterations) by MA, scored semiquantitatively for synovitis (graduated from 0-III degree), were correlated. Additionally, normal radiographs of the hands were performed and compared with MRI findings concerning the detection of bony lesions. Evaluation of the 30 MRI and MA examination revealed highly significant correlations (p < 0.0001) for the parameters of synovial extension (MRI/MA), cortical alterations (MRI/MA) and synovial enhancement (MRI) compared to synovial hyperemia and vascularity (MA). We found significant correlations for parameters of activity and chronicity of RA pathology as assessed by MRI and MA. The detection rate of cortical lesions by MRI was two and a half times higher than by X-ray. MRI findings of MCP-II joints compared to those of MCP III-V showed that the MCP-II joint was more strongly involved.

Adult↗
PubMed2002

Differential diagnosis of hyperthyroidism: Doppler sonographic quantification of thyroid blood flow distinguishes between Graves' disease and diffuse toxic goiter.

The aim of our study was to evaluate the usefulness of color duplex sonography to distinguish Graves' disease from diffuse toxic goiter. 24 patients with Graves' disease and 13 patients with diffuse toxic goiter underwent B-mode- and color duplex sonography of the thyroid gland. All patients had hyperthyroidism and elevated (99m)Tc-uptake. Spectral Doppler recordings were obtained at all thyroid arteries. Representative color flow maps of the thyroid gland were analyzed, calculating the percentage area of the thyroid gland, occupied by color pixels (color pixel density). The B-mode ultrasound pattern was subjectively assessed on a 4-point rating scale. In patients with Graves' disease the mean peak systolic velocity (PSV) (SD) was 110 (+/- 49) cm/s, the mean volume flow rate (VFR) was 123 ( +/- 67) ml/min and the mean color pixel density (CPD) was 33 (+/- 12) %. For patients with diffuse toxic goiter mean PSV (SD) was 43 ( +/- 9) cm/s (p < 0.001), mean VFR was 23 (+/- 10) ml/min (p < 0.001) and mean CPD was 9 (+/- 6) % (p = 0.007). CPD and spectral duplex recordings were positively correlated (CPD/PSV: rs = 0.77, CPD/VFR: rs = 0.75; p < 0.0001). No significant differences were observed concerning RI values. Sensitivity was 87% and specificity 92% for CPD and VFR and 87% and 100% for PSV. We conclude, that color duplex sonography can reliably distinguish diffuse toxic goiter from Graves' disease and therefore contributes significantly to the differential diagnosis of hyperthyroidism in diffuse thyroid disease.

Adult↗
PubMed2002

[Dynamic MRI of the lumbar spine for the evaluation of microcirculation during anti-angiogenetic therapy in patients with myelodysplastic syndromes].

PURPOSE: Evaluation of MRI perfusion parameters of the lumbar spine in patients with myelodysplastic syndromes (MDS) to determine the vascularisation and anti-angiogenetic effects of thalidomide therapy. MATERIAL AND METHODS: In 20 healthy normal persons and 28 MDS patients a dynamic contrast-enhanced MRI (d-MRI) of the lumbar spine was performed. After the initial d-MRI-investigation 24 of the 28 MDS patients received an anti-angiogenetic therapy with thalidomide. With an average of 4.2 months after the beginning of therapy a d-MRI-follow-up examination in 9 of these patients was performed. The amplitude and exchange-rate constant were calculated and a statistical comparison of these values between healthy persons and MDS patients as well as a correlation with the clinical course was executed. RESULTS: Compared with the normal controls the MDS patients showed a higher amplitude (normal persons: 14.4 +/- 5.2, MDS: 24.8 +/- 8.1) and exchange-rate constant (normal persons: 0.124 +/- 0.042, MDS: 0.136 +/- 0.036). In 7 of 9 MDS patients undergoing thalidomide therapy a reduction of the amplitude and exchange rate constant values was evident in the d-MRI follow-up examinations. Clinically these patients showed a therapy response with complete or partial disease remission. CONCLUSIONS: In MDS patients significantly higher d-MRI parameters can be demonstrated than in normal persons. Under anti-angiogenetic treatment these values decrease in case of a response to therapy. Thus, d-MRI seems suitable for the evaluation of anti-angiogenetic therapy effects.

Adult↗
PubMed2002

[User friendly analysis of MR investigations of the cerebral perfusion: Windows(R)-based image processing].

PURPOSE: Quick and user-friendly analysis of perfusion and diffusion weighted MRI by means of interactive computer software. METHOD: A Windows(R)-based software was developed for analysis of perfusion (PWI) and diffusion (DWI) MR imaging. The computer program was developed in the programming language C++ using optimized algorithms, so that a high computing speed on Win95/98/NT systems is achieved. The established SVD algorithms of Østergaard et al. for quantitative perfusion analysis were implemented. RESULTS: Perfusion parameter maps of the cerebral blood flow (rCBF), the mean transit time (MTT) and the cerebral blood volume (rCBV) in consideration of the arterial input function (AIF) can be calculated and visualized using color tables. Additionally, the calculation of "time-to-peak" maps (TTP) and of maps of the percentage change in signal intensity (PC) is possible. The analysis of n = 10 normal persons shows perfusion values that agree with those found in the literature. DISCUSSION: With the computer program developed here color-coded perfusion parameter maps can be calculated easily. Because of the high computing speed it is possible to get information about tissue perfusion on the basis of the large MR data sets even in acute investigations.

Algorithms↗
PubMed2002

Multi-slice CT-colonography in low-dose technique--Preliminary results.

PURPOSE: Assessment of Multi-Slice CT-colonography (MSCTC) with standard and low-dose technique in comparison to conventional colonoscopy (CC). MATERIALS AND METHODS: After standardized bowel cleansing, 28 men and 24 women (mean age 60,3 years) underwent CC within two hours after MSCTC had been performed (4 x 2.5 mm collimation, 3 mm slice width, 17.5 mm table feed, 120 kVp). In 19 patients, MSCTC was performed with 120 mAs (CTDI w, eff : 11.28 mGy), and in 33 patients with 10 mAs (CTDI w, eff : 0.94 mGy), respectively. After noise reduction using mathematical algorithms by a dedicated software (ECCET), images were analyzed by two blinded readers in simultaneously displayed 2D- and 3D-modes. Findings in MSCTC were compared to the results obtained with CC. RESULTS: Calculated effective doses ranged between 9 and 12 mSv for 120 mAs, and between 0.75 and 1 mSv for the low-dose technique. In standard dose MSCTC, 20 of 25 lesions (80 %) were found: all 7 tumors (100 %), one large polyp (> 10 mm; 100 %), 6 of 7 medium sized polyps (9.9 to 5 mm; 86 %) and 6 of 10 small polyps (< 5 mm; 60 %). In low-dose MSCTC, 32 of 44 lesions (73 %) were seen: all three large polyps (100 %), 13 of 14 medium sized polyps (93 %) and 16 of 27 small polyps (59 %). An overall sensitivity of 78 % with a specificity of 68 % was calculated. False positive findings were seen mostly for small lesions (12 for standard dose, 11 for low-dose). CONCLUSION: Despite a 12-fold reduction of radiation exposure, MSCTC in low-dose technique performs comparably well to standard dose MSCTC. After mathematical noise reduction, more than 90 % of polyps larger than 5 mm can be detected.

Algorithms↗
PubMed2002

[Does dynamic contrast-enhanced MRI enable recognition of development of vertebral fractures in multiple myeloma?].

PURPOSE: To compare the value of MRI sequences with dynamic MRI measurements (d-MRT) for the assessment of risk of lumbar vertebral fractures in patients with multiple myeloma. MATERIAL AND METHODS: In 10 patients with multiple myeloma a sagittal T 1 -, T 2 -weighted spin-echo and an inversion-recovery sequence were performed. For dynamic measurements a fast gradient-echo sequence (turbo fast low angle shot 2 D) with machine-controlled Gd-DTPA administration was used. The presence of bone marrow abnormalities was determined and additionally the value of the highest signal increase (amplitude Alpha) was calculated for each of the 50 vertebral bodies. The subsequent development of vertebral fractures was assessed by MRI at a mean time interval of 6.2 months after the initial d-MRI. The pattern of marrow involvement and the amplitudes of the vertebral bodies that collapsed in the observation period were statistically compared with those of the vertebral bodies that did not collapse. RESULTS: During the follow-up period newly or progressive fractures occurred in 6 of 10 patients (7 of 50 vertebral bodies). The degree of pathological signal changes that preceded fractures was not significantly different (p > 0.05) from that of the other contemporary lesions identified in vertebral bodies that did not collapse in follow-up. In contrast, the amplitude of vertebrae that collapsed (A: 33.1 +/- 8.2) was significantly higher (p < 0.0001) than the amplitude of vertebrae that did not collapse (A: 16.7 +/- 4.2). The amplitude was a reliable predictor of vertebrae that collapsed in all cases. CONCLUSION: In contrast to the analysis of marrow lesions detected with non-dynamic MRI, this study suggests that the perfusion-parameter amplitude in dynamic contrast-enhanced MRI is a potentially relevant value to predict the risk of vertebral fractures in patients with multiple myeloma.

Adult↗
PubMed2002

[Quality control of sonography courses in advanced training of physicians: analysis of present status and potential for improvement].

AIM: Since 1995 sonography represents the diagnostic imaging procedure most commonly applied (52 %) by physicians working in the public health sector. On the account of the high cost of sonography (around 2,5 billion DM in 1998) it seems justified to intensify the quality control of advanced sonography training courses for physicians. This study was set out to evaluate the learning efficiency and teaching quality of sonography training courses for doctors. We also aimed at testing, evaluating and carefully optimising modern concepts for sonography training based on recognised didactic criteria. METHODS: 34 courses in B-mode sonography and colour-Doppler sonography of 5 regional and national institutions were evaluated on the basis of standardised questionnaires by observers taking part in the courses incognito. The control group was formed by 332 physicians taking part in ten sonography courses which were structured in the way of alternating training modules with practical final exams based on OSCE criteria. With the help of modern imaging media it was intended to make these courses as illustrative as possible, including practical exercises in small groups of up to five people. Subsequent evaluation was based on standardised questionnaires. The attendance quota of the participants served as an additional comparative value for the acceptance of different teaching concepts. RESULTS: We observed significant deficits in the didactic concepts of numerous ultrasound courses offered externally: there was a high prevalence of extended frontal teaching with noticeably tiring effects as well as unstructured practical exercises in large groups which resulted in high numbers of absenteeism of the participants. The evaluation of the newly drawn up course concepts, however, demonstrated highly significant and unquestionable advantages of alternating teaching in small groups. DISCUSSION: Background information from the field of pedagogical psychology is supplied and the application of current learning theories to new concepts of ultrasound courses is demonstrated. CONCLUSION: Instructors of sonography courses need to be well trained in modern teaching methods. This study shows a variety of current concepts and provides a list of easily applicable didactic quality criteria for the conception of ultrasound courses.

Curriculum↗
PubMed2002

Dose reduction in multi-slice CT of the heart by use of ECG-controlled tube current modulation ("ECG pulsing"): phantom measurements.

PURPOSE: To evaluate the effect of ECG-controlled tube current modulation on radiation exposure in retrospectively-ECG-gated multislice CT (MSCT) of the heart. MATERIAL AND METHODS: Three different cardiac MSCT protocols with different slice collimation (4 x 1, and 4 x 2.5mm), and a pitch-factor of 1.5 and 1.8 were investigated at a multi-slice CT scanner Somatom Volume Zoom, Siemens. An anthropomorphic Alderson-Rando phantom was equipped with LiF-thermoluminescence dosimeters at several organ sites, and effective doses were calculated using ICRP-weighting factors. Scan protocols were performed with ECG-controlled tube current modulation ("ECG pulsing") at two different heart rates (60 and 80 bpm). These data were compared to previous data from MSCT of the heart without use of "ECG pulsing". RESULTS: Radiation exposure with (60 bpm) and without tube current modulation using a 2.5 mm collimation was 1.8 mSv and 2.9 mSv for females, and 1.5 mSv and 2.4 mSv for males, respectively. For protocols using a 1 mm collimation with a pitch-factor of 1.5 (1.8), radiation exposure with and without tube current modulation was 5.6 (6.3) mSv and 9.5 (11.2) mSv for females, and 4.6 (5.2) mSv and 7.7 (9.2) mSv for males, respectively. At higher heart rates (80 bpm) radiation exposure is increased from 1.5 - 1.8 mSv to 1.8 - 2.1 mSv, using the 2.5 mm collimation, and from 4.6 - 5.6 mSv to 5.9 - 7.2 mSv, for protocols using 1 mm collimation. CONCLUSIONS: The ECG-controlled tube current modulation allows a dose reduction of 37 % to 44 % when retrospectively ECG-gated MSCT of the heart is performed. The tube current - as a function over time - and therefore the radiation exposure is dependent on the heart rate.

Coronary Angiography↗