PREFUL MRI for Monitoring Perfusion and Ventilation Changes after Elexacaftor-Tezacaftor-Ivacaftor Therapy for Cystic Fibrosis: A Feasibility Study.

Purpose To assess the feasibility of monitoring the effects of elexacaftor-tezacaftor-ivacaftor (ETI) therapy on lung ventilation and perfusion in people with cystic fibrosis (CF), using phase-resolved functional lung (PREFUL) MRI. Materials and Methods This secondary analysis of a multicenter prospective study was carried out between August 2020 and March 2021 and included participants 12 years or older with CF who underwent PREFUL MRI, spirometry, sweat chloride test, and lung clearance index assessment before and 8-16 weeks after ETI therapy. For PREFUL-derived ventilation and perfusion parameter extraction, two-dimensional coronal dynamic gradient-echo MR images were evaluated with an automated quantitative pipeline. T1- and T2-weighted MR images and PREFUL perfusion maps were visually assessed for semiquantitative Eichinger scores. Wilcoxon signed rank test compared clinical parameters and PREFUL values before and after ETI therapy. Correlation of parameters was calculated as Spearman ρ correlation coefficient. Results Twenty-three participants (median age, 18 years [IQR: 14-24.5 years]; 13 female) were included. Quantitative PREFUL parameters, Eichinger score, and clinical parameters (lung clearance index = 21) showed significant improvement after ETI therapy. Ventilation defect percentage of regional ventilation decreased from 18% (IQR: 14%-25%) to 9% (IQR: 6%-17%) (P = .003) and perfusion defect percentage from 26% (IQR: 18%-36%) to 19% (IQR: 13%-24%) (P = .002). Areas of matching normal (healthy) ventilation and perfusion increased from 52% (IQR: 47%-68%) to 73% (IQR: 61%-83%). Visually assessed perfusion scores did not correlate with PREFUL perfusion (P = .11) nor with ventilation-perfusion match values (P = .38). Conclusion The study demonstrates the feasibility of PREFUL MRI for semiautomated quantitative assessment of perfusion and ventilation changes in response to ETI therapy in people with CF. Keywords: Pediatrics, MR-Functional Imaging, Pulmonary, Lung, Comparative Studies, Cystic Fibrosis, Elexacaftor-Tezacaftor-Ivacaftor Therapy, Fourier Decomposition, PREFUL, Free-Breathing Proton MRI, Pulmonary MRI, Perfusion, Functional MRI, CFTR, Modulator Therapy, Kaftrio Clinical trial registration no. NCT04732910 Supplemental material is available for this article. © RSNA, 2024.

[Imaging of congenital heart defects with a focus on magnetic resonance imaging and computed tomography]. / Bildgebung angeborener Herzfehler mit Fokus auf Magnetresonanz- und Computertomographie.

CLINICAL ISSUE: Due to advances in diagnostics and therapy, the survival rate of patients with congenital heart defects is continuously increasing. The aim of this review is to compare various imaging modalities that are used in the diagnosis of congenital heart defects. METHODS: Transthoracic echocardiography is the imaging method of choice in the presence of a congenital heart defect because of its wide availability and non-invasiveness. It can be complemented by transesophageal echocardiography, cardiac catheterization, computed tomography (CT), and magnetic resonance imaging (MRI) of the heart and vessels close to the heart. METHODICAL INNOVATIONS: The radiation exposure of CT examinations of the heart is continuously decreasing because of improved technologies. MRI is also being continuously optimized, e.g., by the acquisition of MR angiographies without contrast medium application or a thin three-dimensional (3D) visualization of the entire heart with the possibility of reconstruction in all spatial planes (whole-heart technique) as well as 2D to 4D flow. PRACTICAL RECOMMENDATION: Due to the complexity of congenital heart defects and the variety of possible pathologies, the choice of imaging modality and its exact performance has to be coordinated in an interdisciplinary context and individually adapted.

[Imaging after kidney transplantation in childhood and adolescence]. / Bildgebung nach Nierentransplantation im Kindes- und Jugendalter.

The ultrasound (US) examination is the most important imaging procedure in the clinical care of children with chronic kidney disease, the assessment before kidney transplantation and in the acute and chronic phase after successful kidney transplantation. In trained hands, particularly with experience in Doppler sonography, US ensures that vascular complications, such as occlusions, thrombosis, stenosis as well as non-vascular complications, e.g., urinary tract dilatation, abscesses, hematomas, urine leaks or lymphoceles, are cost-effectively and rapidly diagnosed at any time. For the diagnosis of acute rejection, the US signs in the intraindividual course are only suggestive, but not specific. The gold standard for the diagnosis of acute rejection is a kidney biopsy. In these cases, US serves to exclude other causes. The use of multimodal techniques, various Doppler techniques and microvascular procedures, such as superb microvascular imaging (SMI) or B­flow and contrast-enhanced ultrasonography (CEUS), optimizes the imaging in the context of transplantations in children. Magnetic resonance imaging with diffusion-weighed imaging (DWI), magnetic resonance angiography (MRA) and magnetic resonance urography (MRU) as well as functional MRU (fMRU) performed with the administration of gadolinium-containing contrast agents, are part of the extended diagnostics and possibly necessary for surgical planning in the early phase after kidney transplantation and for long-term assessment after transplantation. Excretory urography is associated with ionizing radiation and intravenous administration of iodine-containing contrast medium and is obsolete in children. Computed tomography (CT) using age-adapted and weight-adapted dose protocols is an alternative in emergencies if MRI is not available.

Effect of CFTR modulator therapy with elexacaftor/tezacaftor/ivacaftor on pulmonary ventilation derived by 3D phase-resolved functional lung MRI in cystic fibrosis patients.

OBJECTIVES: To investigate whether 3D phase-resolved functional lung (PREFUL)-MRI parameters are suitable to measure response to elexacaftor/tezacaftor/ivacaftor (ETI) therapy and their association with clinical outcomes in cystic fibrosis (CF) patients. METHODS: Twenty-three patients with CF (mean age: 21; age range: 14-46) underwent MRI examination at baseline and 8-16 weeks after initiation of ETI. Morphological and 3D PREFUL scans assessed pulmonary ventilation. Morphological images were evaluated using a semi-quantitative scoring system, and 3D PREFUL scans were evaluated by ventilation defect percentage (VDP) values derived from regional ventilation (RVent) and cross-correlation maps. Improved ventilation volume (IVV) normalized to body surface area (BSA) between baseline and post-treatment visit was computed. Forced expiratory volume in 1 second (FEV1) and mid-expiratory flow at 25% of forced vital capacity (MEF25), as well as lung clearance index (LCI), were assessed. Treatment effects were analyzed using paired Wilcoxon signed-rank tests. Treatment changes and post-treatment agreement between 3D PREFUL and clinical parameters were evaluated by Spearman's correlation. RESULTS: After ETI therapy, all 3D PREFUL ventilation markers (all p < 0.0056) improved significantly, except for the mean RVent parameter. The BSA normalized IVVRVent was significantly correlated to relative treatment changes of MEF25 and mucus plugging score (all |r| > 0.48, all p < 0.0219). In post-treatment analyses, 3D PREFUL VDP values significantly correlated with spirometry, LCI, MRI global, morphology, and perfusion scores (all |r| > 0.44, all p < 0.0348). CONCLUSIONS: 3D PREFUL MRI is a very promising tool to monitor CFTR modulator-induced regional dynamic ventilation changes in CF patients. CLINICAL RELEVANCE STATEMENT: 3D PREFUL MRI is sensitive to monitor CFTR modulator-induced regional ventilation changes in CF patients. Improved ventilation volume correlates with the relative change of mucus plugging, suggesting that reduced endobronchial mucus is predominantly responsible for regional ventilation improvement. KEY POINTS: • 3D PREFUL MRI-derived ventilation maps show significantly reduced ventilation defects in CF patients after ETI therapy. • Significant post-treatment correlations of 3D PREFUL ventilation measures especially with LCI, FEV1 %pred, and global MRI score suggest that 3D PREFUL MRI is sensitive to measure improved regional ventilation of the lung parenchyma due to reduced inflammation induced by ETI therapy in CF patients. • 3D PREFUL MRI-derived improved ventilation volume (IVV) correlated with MRI mucus plugging score changes suggesting that reduced endobronchial mucus is predominantly responsible for regional ventilation improvement 8-16 weeks after ETI therapy.

Multiparametric Cardiovascular MRI Assessment of Post-COVID Syndrome in Children in Comparison to Matched Healthy Individuals.

BACKGROUND: Post-COVID syndrome (PCS) can adversely affect the quality of life of patients and their families. In particular, the degree of cardiac impairment in children with PCS is unknown. OBJECTIVE: The aim of this study was to identify potential cardiac inflammatory sequelae in children with PCS compared with healthy controls. METHODS: This single-center, prospective, intraindividual, observational study assesses cardiac function, global and segment-based strains, and tissue characterization in 29 age- and sex-matched children with PCS and healthy children using a 3 T magnetic resonance imaging (MRI). RESULTS: Cardiac MRI was carried out over 36.4 ± 24.9 weeks post-COVID infection. The study cohort has an average age of 14.0 ± 2.8 years, for which the majority of individuals experience from fatigue, concentration disorders, dyspnea, dizziness, and muscle ache. Children with PSC in contrast to the control group exhibited elevated heart rate (83.7 ± 18.1 beats per minute vs 75.2 ± 11.2 beats per minute, P = 0.019), increased indexed right ventricular end-diastolic volume (95.2 ± 19.2 mlm -2 vs 82.0 ± 21.5 mlm -2 , P = 0.018) and end-systolic volume (40.3 ± 7.9 mlm -2 vs 34.8 ± 6.2 mlm -2 , P = 0.005), and elevated basal and midventricular T1 and T2 relaxation times ( P < 0.001 to P = 0.013). Based on the updated Lake Louise Criteria, myocardial inflammation is present in 20 (69%) children with PCS. No statistically significant difference was observed for global strains. CONCLUSIONS: Cardiac MRI revealed altered right ventricular volumetrics and elevated T1 and T2 mapping values in children with PCS, suggestive for a diffuse myocardial inflammation, which may be useful for the diagnostic workup of PCS in children.

Titanium nitride coating of pectus bar increases metal contamination after minimally-invasive repair of pectus excavatum.

INTRODUCTION: Previous studies demonstrated a release of toxic metals, e.g. nickel and chromium, from stainless steel bars used for minimally invasive repair of pectus excavatum (MIRPE). In the present study, we investigated the impact of titanium nitride coating on the metal release and exposure of MIRPE patients. MATERIAL AND METHODS: We analyzed the courses of nickel and chromium levels in blood, urine and local tissue in patients undergoing MIRPE with a titanium nitride coated pectus bar between 03/2017 and 10/2018. Sample collection was scheduled prior to MIRPE, at defined postoperative time points and at bar removal. Additionally, we evaluated irritative symptoms. Results were compared to a control group who received uncoated stainless steel bars in a previous time period (03/2015-02/2017). RESULTS: 12 patients received coated pectus bars (mean age 15.7 years). The control group included 28 patients. After implantation of a titanium nitride coated bar, significant increase in systemic nickel and chromium levels after one, two and three years was noted. In an interim analysis one year after MIRPE, we observed patients with coated bars to have significantly elevated trace metal values compared to the control group. This elevation persisted throughout the observation period. Tissue metal values were also significantly increased. Irritative symptoms occurred significantly more often in study patients compared to controls (50.0% vs. 14.3%). CONCLUSIONS: Coating of pectus bars with titanium nitride failed to reduce metal contamination after MIRPE. Instead, it resulted in a significant increase of trace metal levels after MIRPE, compared to patients with stainless steel bars, which may be explained by wear of the coating and inter-component mobilization processes.

Variants in FGF10 cause early onset of severe childhood interstitial lung disease: A detailed description of four affected children.

INTRODUCTION: Fibroblast growth factor 10 (FGF10) is a signaling molecule with a well-established role for lung branching morphogenesis. Rare heterozygous, deleterious variants in the FGF10 gene are known causes of the lacrimo-auriculo-dento-digital (LADD) syndrome and aplasia of lacrimal and salivary glands. Previous studies indicate that pathogenic variants in FGF10 can cause childhood Interstitial Lung Disease (chILD) due to severe diffuse developmental disorders of the lung, but detailed reports on clinical presentation and follow-up of affected children are lacking. METHODS: We describe four children with postnatal onset of chILD and heterozygous variants in FGF10, each detected by exome or whole genome sequencing. RESULTS: All children presented with postnatal respiratory failure. Two children died within the first 2 days of life, one patient died at age of 12 years due to right heart failure related to severe pulmonary hypertension (PH) and one patient is alive at age of 6 years, but still symptomatic. Histopathological analysis of lung biopsies from the two children with early postpartum demise revealed diffuse developmental disorder representing acinar dysplasia and interstitial fibrosis. Sequential biopsies of the child with survival until the age of 12 years revealed alveolar simplification and progressive interstitial fibrosis. DISCUSSION: Our report extends the phenotype of FGF10-related disorders to early onset chILD with progressive interstitial lung fibrosis and PH. Therefore, FGF10-related disorder should be considered even without previously described syndromic stigmata in children with postnatal respiratory distress, not only when leading to death in the neonatal period but also in case of persistent respiratory complaints and PH.

[Li-Fraumeni syndrome]. / Li-Fraumeni-Syndrom.

BACKGROUND: The autosomal dominant inherited Li-Fraumeni syndrome (LFS) increases the lifetime risk of developing a malignancy to almost 100%. Although breast cancer, central nervous system (CNS) tumors and sarcomas are particularly common, tumors can ultimately occur almost anywhere in the body. As causal therapy is not available, the primary focus for improving the prognosis is early cancer detection. To this end, current cancer surveillance recommendations include a series of examinations including regular imaging beginning at birth. CHALLENGES IN IMAGING IN LFS: Due to the wide range of tumor entities that can occur in individuals affected by LFS, a sensitive detection requires imaging of various tissue contrasts; however, because life-long screening is potentially initiated at a young age, this requirement for comprehensiveness must be balanced against the presumed high psychological burden associated with frequent or invasive examinations. As radiation exposure may lead to an increased (secondary) tumor risk, computed tomography (CT) and X­ray examinations should be avoided as far as possible. CURRENT STATUS AND PERSPECTIVES: Because annual whole-body magnetic resonance imaging (MRI) has no radiation exposure and yet a high sensitivity for many tumors, it forms the basis of the recommended imaging; however, due to the rarity of the syndrome, expertise is sometimes lacking and whole-body MRI examinations are performed heterogeneously and sometimes with limited diagnostic quality. Optimization and standardization of MRI protocols should therefore be pursued. In addition, the need for an intravenously administered contrast agent has not been conclusively clarified despite its high relevance.

[Chest X-rays in children and adolescents : Indications and limitations]. / Röntgenuntersuchungen des Thorax bei Kindern und Jugendlichen : Indikationen und Limitationen.

CLINICAL ISSUE: Chest X­ray is the most commonly performed X­ray examination in children and adolescents. The aim of this review is to present the benefit of this radiologic modality, but also its limitations. METHODS: Compared with older children, most X­ray examinations of the chest were performed in newborns. After the neonatal period, this review focusses on the diagnosis of inflammatory pulmonary changes, foreign body aspiration, detection of pulmonary nodules, and cystic fibrosis. METHODOLOGICAL INNOVATIONS: The radiation exposure of X­ray examinations is continuously decreasing due to technical innovations. However, other imaging modalities were also continuously being optimized; therefore, alternatives without radiation exposure, i.e., magnetic resonance imaging [MRI] and ultrasound, should be considered in case of specific clinical indications. PRACTICAL RECOMMENDATION: Even if the diagnostic performance of chest X­ray examinations is often minor compared to computed tomography or MRI, chest X­ray still has a high value in children and adolescents, due to its ubiquitous availability and the relatively simple acquisition.

Coil embolisation for massive haemoptysis in cystic fibrosis.

INTRODUCTION: Massive haemoptysis is a life-threatening event in advanced cystic fibrosis (CF) lung disease with bronchial artery embolisation (BAE) as standard of care treatment. The aim of our study was to scrutinise short-term and long-term outcomes of patients with CF and haemoptysis after BAE using coils. METHODS: We carried out a retrospective cohort study of 34 adult patients treated for massive haemoptysis with super selective bronchial artery coil embolisation (ssBACE) between January 2008 and February 2015. Embolisation protocol was restricted to the culprit vessel(s) and three lobes maximum. Demographic data, functional end-expiratory volume in 1 s in % predicted (FEV1% pred.) and body mass index before and after ssBACE, sputum colonisation, procedural data, time to transplant and time to death were documented. RESULTS: Patients treated with ssBACE showed significant improvement of FEV1% pred. after embolisation (p=0.004) with 72.8% alive 5 years post-ssBACE. Mean age of the patients was 29.9 years (±7.7). Mean FEV1% pred. was 45.7% (±20.1). Median survival to follow-up was 75 months (0-125). Severe complication rate was 0%, recanalisation rate 8.8% and 5-year-reintervention rate 58.8%. Chronic infection with Pseudomonas aeruginosa was found in 79.4%, Staphylococcus areus in 50% and Aspergillus fumigatus in 47.1%. DISCUSSION: ssBACE is a safe and effective treatment for massive haemoptysis in patients with CF with good results for controlling haemostasis and excellent short-term and long-term survival, especially in severely affected patients with FEV<40% pred. We think the data of our study support the use of coils and a protocol of careful and prudent embolisation.

[Abdominal imaging in cystic fibrosis]. / Abdomenbildgebung bei zystischer Fibrose.

CLINICAL ISSUE: Abdominal complications are often the first indications for cystic fibrosis (CF), a multiorgan disease. A broad range of abdominal manifestations are associated with the disease, including gastrointestinal abnormalities (such as meconium ileus in newborns and distal intestinal obstruction syndrome in older children) and hepatobiliary alterations (e.g., cholelithiasis, microgallbladder, hepatosteatosis, biliary cirrhosis). A characteristic finding is pancreatic involvement, which leads to exocrine and over the course of time to endocrine insufficiency. STANDARD RADIOLOGICAL METHODS: Ultrasonography is the preferred and often sole modality for a precise diagnosis of abdominal CF manifestations. However, all imaging modalities can be used, depending on the pathology: X­ray, fluoroscopic examinations, computed tomography, magnetic resonance imaging (also with application of magnetic resonance cholangiopancreatography). METHODICAL INNOVATIONS/PERFORMANCE: Scoring systems are useful for standardized diagnostics. Sonographic findings, described using a scoring system, correlate with clinical symptoms, such as pancreatic lipomatosis with abdominal pain (p = 0.018), flatulence (p = 0.006), and gastroesophageal reflux (p = 0.006). EVALUATION/PRACTICAL RECOMMENDATIONS: A standardized approach with structured reporting is important due to the numerous abdominal CF manifestations. To enable precise follow-up analyses, scoring systems based on sonographic findings are excellent.

Quality and Dose Optimized CT Trauma Protocol - Recommendation from a University Level-I Trauma Center.

Purpose As a supra-regional level-I trauma center, we evaluated computed tomography (CT) acquisitions of polytraumatized patients for quality and dose optimization purposes. Adapted statistical iterative reconstruction [(AS)IR] levels, tube voltage reduction as well as a split-bolus contrast agent (CA) protocol were applied. Materials and Methods 61 patients were split into 3 different groups that differed with respect to tube voltage (120 - 140 kVp) and level of applied ASIR reconstruction (ASIR 20 - 50 %). The CT protocol included a native acquisition of the head followed by a single contrast-enhanced acquisition of the whole body (64-MSCT). CA (350 mg/ml iodine) was administered as a split bolus injection of 100 ml (2 ml/s), 20 ml NaCl (1 ml/s), 60 ml (4 ml/s), 40 ml NaCl (4 ml/s) with a scan delay of 85 s to detect injuries of both the arterial system and parenchymal organs in a single acquisition. Both the quantitative (SNR/CNR) and qualitative (5-point Likert scale) image quality was evaluated in parenchymal organs that are often injured in trauma patients. Radiation exposure was assessed. Results The use of IR combined with a reduction of tube voltage resulted in good qualitative and quantitative image quality and a significant reduction in radiation exposure of more than 40 % (DLP 1087 vs. 647 mGyxcm). Image quality could be improved due to a dedicated protocol that included different levels of IR adapted to different slice thicknesses, kernels and the examined area for the evaluation of head, lung, body and bone injury patterns. In synopsis of our results, we recommend the implementation of a polytrauma protocol with a tube voltage of 120 kVp and the following IR levels: cCT 5mm: ASIR 20; cCT 0.625 mm: ASIR 40; lung 2.5 mm: ASIR 30, body 5 mm: ASIR 40; body 1.25 mm: ASIR 50; body 0.625 mm: ASIR 0. Conclusion A dedicated adaptation of the CT trauma protocol (level of reduction of tube voltage and of IR) according to the examined body region (head, lung, body, bone) combined with a split bolus CA injection protocol allows for a high-quality CT examination and a relevant reduction of radiation exposure in the examination of polytraumatized patients Key Points · Dedicated adaption of the CT trauma protocol allows for an optimized examination.. · Different levels of iterative reconstruction, tube voltage and the CA injection protocol are crucial.. · A reduction of radiation exposure of more than 40 % with good image quality is possible.. Citation Format · Kahn J, Kaul D, Böning G et al. Quality and Dose Optimized CT Trauma Protocol - Recommendation from a University Level-I Trauma Center. Fortschr Röntgenstr 2017; 189: 844 - 854.

Volumetric breast composition analysis: reproducibility of breast percent density and fibroglandular tissue volume measurements in serial mammograms.

BACKGROUND: Volumetric breast composition analysis represents a useful tool for assessing changes in breast composition over time. However, no data exist on the reproducibility of this method in serial mammograms. PURPOSE: To assess the reproducibility of two volumetric breast composition parameters, breast percent density (PD) and fibroglandular tissue volume (FTV), in consecutive mammograms. MATERIAL AND METHODS: Volumetric breast composition analysis to determine PD and FTV was performed in two consecutive unilateral mammograms of 211 patients. All mammograms were obtained on the same digital mammography unit within a maximum interval of 24 months. Volumetric data for analysis for both examinations were available for 174 patients. Thirty-two patients had successful volumetric analysis of additional consecutive examinations on a second digital mammography unit. Inter-examination correlation of measurements and absolute differences were analyzed. Bland-Altman analysis was performed to compare readings from different mammography units. RESULTS: Mean FTV remained constant over the study period. A reduction in PD of 0.5% and a mean increase in breast volume (BV) of 3% were observed. FTV measurements obtained on the same mammography unit were significantly more reproducible than PD measurements (Pearson correlation coefficients of 0.947 and 0.920, respectively; P < 0.05). A 15% difference between mean absolute volume measurements (FTV and BV) obtained on different mammography units was observed (P ≤ 0.001), while mean PD was close to the expected value. CONCLUSION: Volumetric breast composition analysis is highly reproducible in serial mammograms in normal women. FTV is a more reproducible parameter than PD, indicating that absolute quantification of breast parenchyma may be preferable to the measurement of relative parameters such as PD. However, a disadvantage of using FTV is that it is susceptible to systematic differences when measurements are obtained on different imaging platforms.

Pharmacokinetic approach for dynamic breast MRI to indicate signal intensity time curves of benign and malignant lesions by using the tumor flow residence time.

OBJECTIVE: The objective of this study was to evaluate a novel pharmacokinetic approach integrating a tumor model in a whole-body pharmacokinetic model to simulate contrast media-induced signal intensity time curves of breast tumors on dynamic contrast-enhanced magnetic resonance mammography. MATERIALS AND METHODS: A recently developed, whole-body pharmacokinetic model, which describes the distribution and excretion of renally discharged contrast media, has been expanded by integrating a tumor model. The parameters of the general approach including exchange between plasma and interstitium were set as fixed values; only 2 tumor-specific parameters, blood volume fraction Vblood and blood flow kt, were varied. These parameters were adjusted with regard to signal intensity time course data of histologically verified benign and malignant mass-like breast lesions on clinical magnetic resonance imaging examinations (1.5 T) using 2 different contrast media (gadopentetate dimeglumine and gadoterate meglumine) and 2 application doses (0.1 and 0.2 mmol kg body weight). Thus, measured signal intensity time curves were compared with simulated gadolinium (Gd) concentration time curves calculated by the pharmacokinetic model. RESULTS: Benign lesions showed continuous signal increase; malignant tumors presented fast initial signal increase followed by washout effect. According to the pharmacokinetic approach, the variation of the Vblood/kt ratio, which defined the tumor flow residence time τr, led to Gd concentration time curves congruent with the shapes of the measured signal intensity time curves. Low values of τr were characteristic for malignant tumors, and high values were typical for benign lesions; τr of 200 seconds best separated malignant from benign tumors. Thus, the dynamic magnetic resonance imaging data can be well approximated by the pharmacokinetic model considering 2 contrast media and application doses. The calculated Gd concentration time curves of 0.1 mmol kg body weight gadopentetate dimeglumine and gadoterate meglumine overlapped for benign lesions; the curve of gadoterate meglumine was by a factor of 0.8 below the curve of gadopentetate dimeglumine for malignant tumors. Doubling the application dose of gadopentetate dimeglumine from 0.1 to 0.2 mmol kg led to an increase in the Gd concentration time curves for benign lesions but not for malignant tumors. High Gd concentrations with values greater than 1 mmol L were calculated in the vessels of the malignant tumors, outside the determined range of the linear relationship between Gd concentration and signal intensity due to saturation effects. CONCLUSIONS: On the basis of this pharmacokinetic model, the contrast media-induced time curves on dynamic contrast-enhanced magnetic resonance mammography can be classified by a single kinetic parameter, the tumor flow residence time τr, into benign (τr >200 seconds) and malignant (τr <200 seconds) curve shapes. Possible clinical application of this model is to create pharmacokinetic maps, displaying tumor flow residence times, for computer-assisted diagnosis, which may be integrated into clinical routine for the diagnosis of breast lesions.