Interventional closure of a bronchopleural fistula in a 2 year old child with detachable coils.

BACKGROUND: Bronchopleural fistula (BPF) is a severe complication following pneumonia or pulmonary surgery, resulting in persistent air leakage (PAL) and pneumothorax. Surgical options include resection, coverage of the fistula by video-assisted thoracoscopic surgery (VATS), or pleurodesis. Interventional bronchoscopy is preferred in complex cases and involves the use of sclerosants, sealants and occlusive valve devices. CASE PRESENTATION: A 2.5-year-old girl was admitted to our hospital with persistent fever, cough and dyspnoea. Clinical and radiological examination revealed right-sided pneumonia and pleural effusion. The child was started on antibiotics, and the effusion was drained by pleural drainage. Following removal of the chest tube, the child developed tension pneumothorax. Despite insertion of a new drain, the air leak persisted. Thoracoscopic debridement with placement of another new drain was performed after 4 weeks, without abolishment of the air leak. Bronchoscopy with bronchography revealed a BPF in right lung segment 3 (right upper-lobe anterior bronchus). We opted for an interventional approach that was performed under general anaesthesia during repeat bronchoscopy. Following bronchographic visualisation of the fistula, a 2.7 French microcatheter was placed in right lung segment 3 (upper lobe), allowing occlusion of the fistula by successive implantation of 4 detachable high-density packing volume coils, which were placed into the fistula. Subsequent bronchography revealed no evidence of residual leakage, and the chest tube was removed 2 days later. The chest X-ray findings normalized, and follow-up over 4 years was uneventful. CONCLUSIONS: Bronchoscopic superselective occlusion of BPF using detachable high-density packing large-volume coils was a successful minimally invasive therapeutic intervention performed with minimal trauma in this child and has not been reported thus far. In our small patient, the short interventional time, localized intervention and minimal damage in the lung seemed superior to the corresponding outcomes of surgical lobectomy or pleurodesis in a young growing lung, enabling normal development of the surrounding tissue. Follow-up over 4 years did not show any side effects and was uneventful, with normal lung-function test results to date.

123Iodine-metaiodobenzylguanidine scintigraphy versus whole-body magnetic resonance imaging with diffusion-weighted imaging in children with high-risk neuroblastoma - pilot study.

BACKGROUND: The prognostic value of the International Society of Paediatric Oncology European Neuroblastoma Research Network (SIOPEN) skeletal score using 123iodine-metaiodobenzylguanidine (MIBG) has been confirmed for people with high-risk neuroblastoma. Whole-body MRI with diffusion-weighted imaging is used increasingly. OBJECTIVE: To compare the original SIOPEN score and its adaption by diffusion-weighted imaging in high-risk stage 4 neuroblastoma and to evaluate any consequences of score differences on overall survival. MATERIALS AND METHODS: This retrospective observational study included pediatric patients who underwent MIBG scintigraphy and whole-body MRI, including diffusion-weighted imaging, between 2010 and 2015. Semi-quantitative skeletal scores for each exam were calculated independently. A difference of two or more points was defined as clinically relevant and counted as M+ (more in diffusion-weighted imaging) or S+ (more in MIBG). In cases of a negative result in one of the studies, residual disease of 1 point was also rated as relevant. We tested correlation and differences on an exam basis and also grouped by different therapeutic conditions. Overall survival was used to evaluate prognostic relevance. RESULTS: Seventeen children with 25 paired examinations were evaluated. Median MIBG scintigraphy score was 0 (interquartile range [IQR] 0-4, range 0-25) vs. a median whole-body MRI score of 1 (IQR 0-5.5, range 0-35) (P=0.018). A relevant difference between whole-body MRI and MIBG scintigraphy was noted in 14 of the 25 paired examinations (M+: n=9; S+: n=5). After treatment, the median survival of cases with M+ was 14 months (IQR 4-59, range 1-74 months), while S+ cases showed a median survival of 49 months (IQR 36-52, range 36-52 months) (P=0.413). CONCLUSION: The SIOPEN scoring system is feasible for whole-body MRI but might result in slightly higher scores, probably because of MRI's superior spatial resolution. Further studies are necessary to validate any impact on prognosis.

Reduction of radiation exposure in scoliosis monitoring using flat detector and pulsed fluoroscopy technology.

A new flat detector and pulsed fluoroscopy technology is available to further reduce radiation exposure in radiological monitoring during scoliosis treatment in children and adolescents. The aim of this study is to compare different settings of the system (opening area(OA) and image quality settings (IQS)) in order to find the optimal parameters with high image quality and the lowest possible radiation exposure. Therefore, we examined four cadaver spines (T1 to sacrum) with the flat detector technique using digital pulsed fluoroscopy and simulated the abdominal soft tissues. The images were merged and evaluated by three different investigators using an established scoring system. For comparison, we used digital radiography images of the cadaver spines. The values for the DAP increased from the small OA (33% ; 0.56 µGy·m²) to the maximum OA (100% ; 0.82 µGy·m²) by 45% (p = .003) and from the low image quality setting (0.57 µGy·m²) to the high setting (0.84 µGy·m²) by 48% (p = .028). Despite the low DAP, the setting 33% OA achieved the best point values for image quality, therefore this setting is clearly preferred. Using a digital fluoroscopy system allows a significant reduction of radiation exposure by a factor of 7.5 (3.88µGy·m² to 0.5µGy·m²) compared to slot- scanning x-ray (EOS). Due to this success, the flat detector and pulsed fluoroscopy technology can be an alternative to established methods such as X-ray and EOS in clinical use.

Forensic age estimation in living adolescents with CT imaging of the clavicula-impact of low-dose scanning on readers' confidence.

OBJECTIVES: Computed tomography (CT) imaging of the clavicula displays the reference standard for forensic bone age diagnostics in adolescents and young adults. Consequently, highest efforts on radiation reduction are warranted. Therefore, the aim of this study was to investigate the feasibility of low-dose (LD) CT imaging of the clavicula for age estimation in living adolescents. METHODS: A total of 207 non-contrast chest CT of 144 patients born between 1988 and 2012, performed in 2018 due to various clinical indications, were included in this retrospective study. The mean patient age was 16.9 ± 6.6 years. Patients were divided into a LD (n = 146) and standard-dose (SD; n = 61) group. Image quality, confidence levels, and ossification stages (using the 5-stage classification including the subgroups 2a-3c) were assessed by two radiologists independently. Radiation dose was determined via dosimetry software. RESULTS: Dose simulation with z-axis reduction to depict the clavicula only resulted in a median exposure of 0.1 mSv (IQR: 0.0) in LD compared with 0.9 mSv (IQR: 0.6) in SD (p < 0.001). The median image quality was rated by both readers significantly worse in LD compared with SD on a Likert scale ranging from 1 to 4 with a median of 3 (IQR: 1) versus 4 (IQR: 0; p < 0.001 for both readers). There was an almost perfect agreement for the ossification stages between both readers with a Cohen's kappa of 0.83 (p < 0.001). Median confidence levels of both readers were not significantly different between LD and SD in the decisive subgroups 2a-3c. CONCLUSIONS: Low-dose CT imaging of the clavicula for age estimation in living adolescents is possible without loss of readers' confidence. KEY POINTS: • Radiological bone age diagnostics in young delinquents with unknown exact chronological age is important as the judicial systems differentiate between youths and adults. • Low-dose computed tomography scanning of the medial clavicular joint for forensic age estimation is feasible in living adolescents without loss of readers' confidence. • Sufficient image quality of the medial clavicular joint for forensic bone age diagnostics in living adolescents is achievable using a median dose of 0.1 mSv.

Retrospective accuracy analysis of MRI based lesion size measurement in neuroblastic tumors: which sequence should we choose?

BACKGROUND: MR imaging of neuroblastic tumors is widely used for assessing the effect of chemotherapy on tumor size. However, there are some concerns that MRI might falsely estimate lesion diameters due to calcification and fibrosis. Therefore, the aim of our study was to compare neuroblastic tumor size based on MRI measurements to histopathology measurements of the resected specimens as standard of reference. METHODS: Inclusion criteria were diagnosis of a neuroblastic tumor, MR imaging within 100 days to surgery and gross total resection without fragmentation of the tumor between 2008 and 2019. Lesion diameters were measured by two radiologists according to RECIST 1.1 in axial plane in T2w turbo spin echo (TSE), diffusion-weighted imaging (DWI), and in T1w pre- and postcontrast sequences. Furthermore, the largest lesion size in three-dimensions was noted. The largest diameter of histopathology measurements of each specimen was used for comparison with MRI. RESULTS: Thirty-seven patients (mean age: 5 ± 4 years) with 38 lesions (neuroblastoma: n = 17; ganglioneuroblastoma: n = 11; ganglioneuroma: n = 10) were included in this retrospective study. There was excellent intra-class correlation coefficient between both readers for all sequences (> 0.9) Tumor dimensions of reader 1 based on axial MRI measurements were significantly smaller with the following median differences (cm): T1w precontrast - 1.4 (interquartile range (IQR): 1.8), T1w postcontrast - 1.0 (IQR: 1.9), T2w TSE: -1.0 (IQR: 1.6), and DWI -1.3 (IQR: 2.2) (p < 0.001 for all sequences). However, the evaluation revealed no significant differences between the three-dimensional measurements and histopathology measurements of the resected specimens regardless of the applied MRI sequence. CONCLUSIONS: Axial MRI based lesion size measurements are significantly smaller than histopathological measurements. However, there was no significant difference between three-dimensional measurements and histopathology measurements of the resected specimens. T2w TSE and T1w postcontrast images provided the lowest deviation and might consequently be preferred for measurements.

Allogeneic hematopoietic stem cell transplantation in two brothers with DNA ligase IV deficiency: a case report and review of the literature.

BACKGROUND: DNA ligase IV deficiency is a rare autosomal recessive disorder caused by hypomorphic mutations in the DNA ligase IV (LIG4) gene. DNA ligase IV is an essential protein for the development of a healthy immune system as well as for the protection of genomic integrity. Apart from typical stigmata, patients with DNA ligase IV deficiency are characterized by progressive bone marrow failure and a predisposition to malignancy. To our knowledge this reported case is the first description of two brothers with ligase IV deficiency who are treated with different hematopoietic stem cell transplantation (HSCT) regimens resulting in vastly divergent outcomes. CASE PRESENTATION: The cases of two brothers suffering from severe recurrent infections and growth retardation are described. The laboratory findings showed pancytopenia with significant lymphopenia. The two boys were diagnosed with DNA ligase IV deficiency, associated with severe combined immunodeficiency (SCID). Both patients received HSCT from two different matched unrelated donors (MUD) at the age of 33 and 18 months. The older brother succumbed post-transplant due to fatal side-effects 143 days after allogeneic HSCT. The younger brother - conditioned with a different regimen - received a T cell depleted graft 4 months later. No severe side-effects occurred, neither post-transplant nor in the following years. Ten years after HSCT the patient is well off, living a normal life and attending a regular high school. His immune system is fully reconstituted, resulting in a maximum of T cell receptor (TCR) diversity, which is a prerequisite for immune competence. However, he still suffers from microcephaly, dwarfism and dystrophy. CONCLUSIONS: This case report gives an example of a successful HSCT as a treatment option in a genetic disorder such as ligase IV deficiency, using a rather mild conditioning regimen. Further studies are required to determine the viability and efficacy of this treatment option.

Correction to: Allogeneic hematopoietic stem cell transplantation in two brothers with DNA ligase IV deficiency: a case report and review of the literature.

After publication of the original article (1), it was brought to our attention that references 24 and 31 are inappropriately cited in the article.

A semiquantitative MRI-Score can predict loss of lung function in patients with cystic fibrosis: Preliminary results.

OBJECTIVES: To evaluate the applicability of a semiquantitative MRI scoring system (MR-CF-S) as a prognostic marker for clinical course of cystic fibrosis (CF) lung disease. METHODS: This observational study of a single-centre CF cohort included a group of 61 patients (mean age 12.9 ± 4.7 years) receiving morphological and functional pulmonary MRI, pulmonary function testing (PFT) and follow-up of 2 years. MRI was analysed by three raters using MR-CF-S. The inter-rater agreement, correlation of score categories with forced expiratory volume in 1 s (FEV1) at baseline, and the predictive value of clinical parameters, and score categories was assessed for the whole cohort and a subgroup of 40 patients with moderately impaired lung function. RESULTS: The inter-rater agreement of MR-CF-S was sufficient (mean intraclass correlation coefficient 0.92). MR-CF-S (-0.62; p < 0.05) and most of the categories significantly correlated with FEV1. Differences between patients with relevant loss of FEV1 (>3%/year) and normal course were only significant for MR-CF-S (p < 0.05) but not for clinical parameters. Centrilobular opacity (CO) was the most promising score category for prediction of a decline of FEV1 (area under curve: whole cohort 0.69; subgroup 0.86). CONCLUSIONS: MR-CF-S is promising to predict a loss of lung function. CO seems to be a particular finding in CF patients with an abnormal course. KEY POINTS: • Lung imaging is essential in the diagnostic work-up of CF patients • MRI serves as a powerful, radiation-free modality in paediatric CF patients • Observational single-centre study showed significant correlation of MR-CF score and FEV 1 • MR-CF score is promising in predicting a loss of lung function.

Fibrolipomatous hamartomas of the median nerve in infancy and early childhood-imaging hallmarks, symptomatology, and treatment.

A fibrolipomatous hamartoma (FLH) is a rare lesion leading to an enlargement of the affected nerve and commonly manifests at the median nerve. Symptomatic patients are mostly adolescents or adults. In children below 10 years, this entity is rather unknown and likely to be misdiagnosed. We report three children with FLH, two severely and one mildly symptomatic, all below 4 years of age at the time of first presentation. Two of three children were initially misdiagnosed. We provide a review of the pertinent clinical and radiological findings of the entity. Two patients had a characteristic macrodactyly. The two symptomatic children underwent surgical carpal tunnel decompression. The intervention relived their symptoms with a long-lasting effect. Surgical reduction of the hamartoma mass is not indicated and medical treatment non-existent. CONCLUSION: A symptomatic FLH of the median nerve is rare in children below the age of 5 years but has to be kept in mind as differential diagnosis in case of wrist and/or palm swelling, macrodactyly, and pain in hand or forearm. MRI is diagnostic, with very characteristic features, which can also be identified in high-resolution nerve ultrasound. This article aims to increase the knowledge about the entity including the diagnostic features and the management options. What is Known: • Fibrolipomatous hamartomas (FLHs) of the median nerve are rare, possibly associated with macrodactyly and tissue growth at the wrist and thenar side of the palm. • An associated carpal tunnel syndrome typically occurs, if at all, in adulthood. What is New: • We describe two children below 4 years with symptomatic carpal tunnel syndrome, experiencing a long-lasting favorable outcome after carpal tunnel decompression. In this age group, only one other child undergoing surgery has been published so far. • MRI and high-resolution ultrasound demonstrate the characteristic features of FLHs and are the diagnostic modalities of choice. Biopsy is not recommended.

Comparison between high-resolution CT and MRI using a very short echo time in patients with cystic fibrosis with extra focus on mosaic attenuation.

BACKGROUND: It would be beneficial to establish pulmonary MRI as a complementary approach to CT for direct visualization of mosaic perfusion, bullae, and emphysema in patients with cystic fibrosis. OBJECTIVES: The purpose of this study was to compare both modalities, CT and MRI, using the Helbich-Bhalla score with a special focus on reliable detection of a mosaic pattern. METHODS: Out of 51 patients examined by MRI on a 1.5-Tesla system during a period of 2 years, 19 patients were scheduled for additional low-dose CT in a clinical context. The MRI protocol comprised a gradient echo (GRE) sequence with a very short echo time (TE = 0.8 ms) in inspiration and expiration, a 3-D GRE sequence in breath hold, and a fast spin echo sequence with respiration and ECG triggering. MDCT was carried out in inspiration and adapted to body weight using 100 or 120 kV, 30-60 mA, 1- and 3-mm slice thicknesses, as well as low and high kernels. Additionally incremental slices in 3 positions were recorded in expiration for distinct detection of air trapping. CT and MRI analyses were performed by two radiologic readers in consensus unaware of the clinical parameters. The Helbich-Bhalla score of both examinations was correlated. Mean difference and accordance were assessed in each category. RESULTS: There was a strong correlation between CT and MRI (R = 0.87, p < 0.01). The mean Helbich-Bhalla score for CT was 12.2 (range 1-18) and for MRI it was 11.7 (range 2-19). The mean difference was 0.5 points. Besides this strong correlation for findings (bronchiectasis, mucus plugging, peribronchial thickening, and consolidation) with a prolonged T2 TE in MRI, we could also state a qualitative agreement of 95-100% in the categories with short T2 and low signal intensity in MRI as emphysema, bullae, and mosaic perfusion. CONCLUSIONS: These results suggest that in our patient group none of the relevant findings were missed by MR imaging and reading.

Thoracoscopic Resection of Lung Nodules following CT-Guided Labeling in Children and Adolescents with Solid Tumors.

Resection of lung metastases in children with solid tumors is regularly hampered by limited intraoperative detectability and relevant operative trauma of the open surgical access. The aim of this study was to analyze thoracoscopic resection of lung metastases in children following CT-guided labeling with coil wires. We retrospectively analyzed data of children and adolescents undergoing this approach at our institution between 2010 and 2022 with regard to technical aspects as well as surgical and oncological data. Within this period, we performed this procedure on 12 patients wherein we resected 18 lesions (1-5 per patient). The median age of patients was 178 months (51-265). The median duration of coil wire placement was 41 min (30-173) and the median surgery time was 53 min (11-157). No conversions were necessary and no intraoperative complications occurred. Complete microscopic resection (R0) was achieved in all labeled lesions and malignant tumor components were found in 5/12 patients. Our study shows that with a careful patient selection, thoracoscopic resection of lung metastases after coil wire labeling is a safe and reproducible procedure in children. Using this approach, lesions that are expected to have a reduced intraoperative detectability during open surgery become resectable. Patients benefit from the minimally invasive surgical access and reduced operative trauma.

Translational immunoPET imaging using a radiolabeled GD2-specific antibody in neuroblastoma.

Background: Antibodies targeting surface expressed disialoganglioside GD2 are increasingly used in neuroblastoma immunotherapy and might also have potential for use in radioimmunotherapy. As such targeted treatments might benefit from a dedicated theranostic approach, we studied the influence of radiolabeling on the binding characteristics of ch14.18 antibodies produced by Chinese hamster ovary (CHO) cells and evaluated the benefit of GD2-ImmunoPET as a potential tool for therapy planning. Methods:64Cu was used to reduce radiation burden, which is of high importance especially in a pediatric patient population. 64Cu-labeling was accomplished using the chelators NOTA- or DOTAGA-NCS. Radiolabeled antibodies were characterized in vitro. [64Cu]Cu-DOTAGA-ch14.18/CHO was studied in a neuroblastoma mouse model (subcutaneous CHP-134 xenografts). In vivo PET and MR images were acquired at 3 h, 24 h, and 48 h p.i. The specificity of binding was verified using GD2-negative tumors (HEK-293 xenografts), a control antibody and in vivo blocking. A first translational application was performed by PET/MRI in a patient with metastasized neuroblastoma. Results: Radiolabeling at an antibody-to-chelator ratio ≥1:10 yielded a product with a radiochemical purity of ≥90% and a specific activity of 0.2-1.0 MBq/µg. Radiochelation was stable over 48 h in PBS, mouse serum or EDTA, and 50.8 ± 3.5% and 50.8 ± 2.0% of the radiolabeled conjugates, prepared at antibody-to-chelator ratios of 1:10 or 1:15, were immunoreactive. In vivo, highly specific accumulation (31.6 ± 5.8% ID/g) in neuroblastoma was shown preclinically. Clinical PET/MR scans using [64Cu]Cu-NOTA-ch14.18/CHO (NOTA used for safety reasons) could visualize neuroblastoma metastases. Conclusions:In vivo,64Cu-labeled ch14.18/CHO is suitable for specific identification of neuroblastoma in PET. A first patient PET indicated the feasibility of the method for clinical translation and the potential utility in image-guided therapy.

Magnetic resonance imaging of lung tissue: influence of body positioning, breathing and oxygen inhalation on signal decay using multi-echo gradient-echo sequences.

PURPOSE: To assess susceptibility related signal decay in lung tissue and to measure the influence of body positioning, together with inspiration and expiration, as well as oxygen inhalation. T2* maps and line shape maps of lung parenchyma were derived from datasets acquired at 0.2 T and compared with findings at 1.5 T. The line shape maps allow for a visualization of the intravoxel frequency distribution of lung parenchyma. MATERIALS AND METHODS: A multiecho spoiled gradient-echo sequence with 16 echoes was implemented both on a 0.2 T [repetition time (TR) = 100 milliseconds, echo time (TE)1 = 2.15 milliseconds, DeltaTE = 2.94 milliseconds, flip angle 30 degrees] and on a 1.5 T magnetic resonance scanner (TR = 100 milliseconds, TE1 = 1.25 milliseconds, DeltaTE = 1.65 milliseconds, flip angle 30 degrees). Sagittal datasets were recorded in 8 healthy volunteers at 0.2 T in supine position under maximal expiration and inspiration and during oxygen breathing. Additional measurements were performed after 20 minutes inside the scanner in supine position and after prone repositioning. In 2 volunteers, further datasets were acquired at 1.5 T. Color-encoded T2* maps and full-width-at-half-maximum (FWHM) maps of the frequency distribution were computed on a pixel-by-pixel basis. T2* maps were generated by mono-exponential fitting and, additionally, with an extended nonexponential fitting approach. The FWHM maps were calculated with a model-free approach using a discrete Fast Fourier Transformation. RESULTS: A notably slower T2* decay was found at 0.2 T (T2*: 5.9-11.8 milliseconds) when compared with 1.5 T (T2*: 1.0-1.4 milliseconds), allowing for the measurement of up to 6 to 8 gradient echoes above the noise level. The T2* maps and the FWHM maps computed from the datasets acquired at 0.2 T allowed regional comparison of the derived parameters. If volunteers were positioned in supine position, expiration resulted in a T2* of 10.9 +/- 1.0 milliseconds and a FWHM of 47.1 +/- 4.0 Hz in the dorsal lung. Significant changes (P < 0.05) were found, eg, in the ventral lung in expiration (T2*: 7.5 +/- 0.8, FWHM: 76.7 +/- 11.2) versus dorsal lung in expiration, in the dorsal lung in inspiration (T2*: 8.4 +/- 1.0, FWHM: 67.8 +/- 12.5) versus dorsal lung in expiration, in the dorsal lung during oxygen breathing (T2*: 8.7 +/- 1.1, FWHM: 52.2 +/- 5.2) versus dorsal lung while breathing room air, and in the dorsal lung in prone position (T2*: 8.5 +/- 0.6, FWHM: 67.0 +/- 9.2) versus dorsal lung in supine position. CONCLUSION: The proposed method allows for the computation of color-encoded T2* maps and FWHM maps of lung parenchyma in good image quality using datasets acquired at 0.2 T. The technique is robust and sensitive to physiological changes of lung magnetic resonance properties, eg, due to the type of body positioning or oxygen breathing.

Radiation Dose Optimization in Pediatric Chest CT: Major Indicators of Dose Exposure in 1695 CT Scans over Seven Years.

PURPOSE: To analyze possible influencing factors on radiation exposure in pediatric chest CT using different approaches for radiation dose optimization and to determine major indicators for dose development. MATERIALS AND METHODS: In this retrospective study at a clinic with maximum care facilities including pediatric radiology, 1695 chest CT examinations in 768 patients (median age: 10 years; range: 2 days to 17.9 years) were analyzed. Volume CT dose indices, effective dose, size-specific dose estimate, automatic dose modulation (AEC), and high-pitch protocols (pitch ≥ 3.0) were evaluated by univariate analysis. The image quality of low-dose examinations was compared to higher dose protocols by non-inferiority testing. RESULTS: Median dose-specific values annually decreased by an average of 12 %. High-pitch mode (n = 414) resulted in lower dose parameters (p < 0.001). In unenhanced CT, AEC delivered higher dose values compared to scans with fixed parameters (p < 0.001). In contrast-enhanced CT, the use of AEC yielded a significantly lower radiation dose only in patients older than 16 years (p = 0.04). In the age group 6 to 15 years, the values were higher (p < 0.001). The diagnostic image quality of low-dose scans was non-inferior to high-dose scans (2.18 vs. 2.14). CONCLUSION: Radiation dose of chest CT was reduced without loss of image quality in the last decade. High-pitch scanning was an independent factor in this context. Dose reduction by AEC was limited and only relevant for patients over 16 years. KEY POINTS: · The radiation dose of pediatric chest CT was reduced in the last decade.. · High-pitch scanning is an independent factor of dose optimization.. · Dose reduction by AEC is limited and only relevant for older children.. CITATION FORMAT: · Esser M, Hess S, Teufel M et al. Radiation Dose Optimization in Pediatric Chest CT: Major Indicators of Dose Exposure in 1695 CT Scans over Seven Years. Fortschr Röntgenstr 2018; 190: 1131 - 1140.

Dynamic magnetic resonance nephrography: is saturation recovery TrueFISP advantageous over saturation recovery TurboFLASH?

PURPOSE: In this volunteer study, 2 navigator-gated strongly T1-weighted saturation-recovery (SR) sequences, a turbo fast low angle shot (TurboFLASH) and a new true fast imaging in steady precession (TrueFISP) readout technique, were compared for suitability in dynamic magnetic resonance nephrography. MATERIALS AND METHODS: Ten healthy volunteers (mean age 26.1 +/- 3.6) were equally divided into 2 subgroups. After bolus-injection of 3.75 mL of gadobutrol (approximately 0.05 mmol/kg body weight), slightly obliqued coronal single-slice images of the kidneys were recorded every 4-5 seconds during free breathing using 1 of the 2 sequences. Time-intensity curves were determined from manually drawn regions-of-interest over the kidney parenchyma. Both sequences were subsequently evaluated with regard to linearity of signal, signal to noise ratio (SNR), and time-dependent behavior of signal intensity curves. RESULTS: : The TurboFLASH readout showed better linearity of the signal behavior as compared with the TrueFISP technique (TurboFLASH: no deviation from linearity down to T1 = 400 milliseconds; TrueFISP at T1 = 700 milliseconds: 12% deviation, at T1 = 400 milliseconds: 19%). The time-intensity curves of the TrueFISP sequence exhibited distinctly lower variability than the TurboFLASH approach. The SNR increased with TrueFISP by 3.4 +/- 0.5-fold for native renal parenchyma and by 3.3 +/- 0.9 for contrast-enhanced renal parenchyma. For split renal function evaluation, the linear regression to the signal increase in the first minutes after the first pass could be performed with higher reliability using the TrueFISP technique (increase of correlation coefficient by 17.1%). CONCLUSION: A SR navigator-gated TrueFISP sequence seems most favorable for dynamic magnetic resonance nephrography due to the high signal yield and low curve variability.

Solitary pulmonary nodules: association between signal characteristics in dynamic contrast enhanced MRI and tumor angiogenesis.

PURPOSE: To estimate the association between signal characteristic of dynamic enhanced MRI using curve types and angiogenesis in solitary pulmonary nodules. MATERIALS AND METHODS: Thirty-six patients with a solitary pulmonary nodule (SPN) ranging in size from 6 to 37 mm (median 17 mm) underwent dynamic contrast enhanced MRI with a time interval of 10 s over a total period of 4 min. Resulting from the time-intensity curves four different enhancement curve profiles (A-D) were defined: type A with strong increase followed by early washout, type B with strong increase without washout, type C with slow increase and type D without relevant increase. Maximum peak (Pmax), slope of the first bolus transit (slope) and washout were calculated. Microvessel densities (MVD) were counted at the margins and at the center of the nodules. The mean MVD of each nodule was calculated. Enhancement characteristics were correlated with MVD grouped by diagnosis and by curve types. Curve types were correlated with the score of vascular endothelial growth factor (VEGF). RESULTS: The frequency of malignancy was 55% (20/36). Using curve types for differentiation between malignant and benign SPN, the sensitivity, specificity and accuracy were 100%, 75% and 89%, respectively. The correlation between Pmax and MVD(mean) for all nodules was moderate (r(s)=0.4, P=0.02). A relevant correlation was found between Pmax and MVD(margin) in curve type A (r(s)=0.63; P=0.04) and Pmax and MVD(mean) in curve type C (r(s)=0.86; P=0.006). No positive correlation was found between Pmax and MVD (mean, center and margin) in curve type B. No significant correlation was found for slope and washout. VEGF score correlated positively with curve types (r(s)=0.67; P<0.001). CONCLUSION: A relevant association between perfusion curve profiles and angiogenesis was found in malignant nodules having early washout and in benign lesion with a slow increase of enhancement. In cases of strong signal increase without washout additional factors for enhancement must be considered. The use of curve profiles could allow for the estimation of the extent of VEGF.

Differentiation between malignant and benign solitary pulmonary nodules with proton density weighted and ECG-gated magnetic resonance imaging.

OBJECTIVE: To estimate performance of MRI for differentiating malignant from benign solitary pulmonary nodules (SPN) using morphological characteristics. MATERIAL AND METHODS: MRI in 46 patients with SPN (mean diameter: 19 mm) was carried out on 1.0 Tesla scanner using ECG-gated, gradient echo sequence. Morphological signs of SPN were determined and compared with previously performed helical-CT, where final diagnosis served as reference with 52% frequency of malignancy. Furthermore, three observers evaluated all images. RESULTS: Significant differences between the two groups were found for nodules shape, margin, inhomogeneity and the vessel-sign in MRI, nodules shape, margin, the vessel-sign, and presence of spicules in CT. Using these signs, AUC were 0.746 for MRI and 0.765 for CT. The mean sensitivity, specificity, and accuracy of observers for MRI/CT were 89%/95%, 42%/41%, 66%/68%, respectively. CONCLUSIONS: Despite discrepancies in morphologic appearance, no significant difference of accuracy between MRI and CT was determined. Further investigations are necessary to demonstrate the clinical use in combination with functional parameters, establishing MRI as a comprehensive diagnostic modality for SPN.

Computer-assisted surgery planning in children with complex liver tumors identifies variability of the classical Couinaud classification.

BACKGROUND: In complex malignant pediatric liver tumors there is an ongoing discussion regarding surgical strategy; for example, primary organ transplantation versus extended resection in hepatoblastoma involving 3 or 4 sectors of the liver. We evaluated the possible role of computer-assisted surgery planning in children with complex hepatic tumors. METHODS: Between May 2004 and March 2016, 24 Children with complex liver tumors underwent standard multislice helical CT scan or MRI scan at our institution. Imaging data were processed using the software assistant LiverAnalyzer (Fraunhofer Institute for Medical Image Computing MEVIS, Bremen, Germany). Results were provided as Portable Document Format (PDF) with embedded interactive 3-dimensional surface mesh models. RESULTS: Median age of patients was 33months. Diagnoses were hepatoblastoma (n=14), sarcoma (n=3), benign parenchyma alteration (n=2), as well as hepatocellular carcinoma, rhabdoid tumor, focal nodular hyperplasia, hemangioendothelioma, or multiple hepatic metastases of a pancreas carcinoma (each n=1). Volumetry of liver segments identified remarkable variations and substantial aberrances from the Couinaud classification. Computer-assisted surgery planning was used to determine surgical strategies in 20/24 children; this was especially relevant in tumors affecting 3 or 4 liver sectors. Primary liver transplantation could be avoided in 12 of 14 hepaoblastoma patients who theoretically were candidates for this approach. CONCLUSIONS: Computer-assisted surgery planning substantially contributed to the decision for surgical strategies in children with complex hepatic tumors. This tool possibly allows determination of specific surgical procedures such as extended surgical resection instead of primary transplantation in certain conditions.

Computed tomographic colonography (CTC): Possibilities and limitations of clinical application in colorectal polyps and cancer.

Colorectal cancer is the second leading cause of cancer-related deaths in Europe and the United States. Most colorectal cancers develop from adenomatous polyps over a number of years. Early detection of polyps eliminates the risk of subsequent carcinomas. Computed tomographic (CT) colonography is a diagnostic technique detecting colorectal neoplasms. With the introduction of multidetector-row computed tomography (MD-CT), CT colonography (CTC) has gained influence as a new diagnostic tool in early detection of colonic pathologies by acquiring volumetric CT data sets of the abdomen. This volumetric data is analyzed using CTC workstations, which provide an interactive display of 2D and 3D images of the colon. In several studies, CTC revealed a high accuracy (sensitivity/patient: 83-100% and specificity/patient: 93-100%) in detecting pathological colonic changes. Furthermore, CTC is an excellent diagnostic technique for the evaluation of patients with incomplete conventional colonoscopy and allows the assessment of extracolonic abdominal and pelvic organs. In this article, the status of CT colonography as a method of detecting colonic polyps and colorectal carcinomas using single- and multidetector-row CT will be reviewed.