Current use of percutaneous image-guided tumor ablation for the therapy of liver tumors: lessons learned from the registry of the German Society for Interventional Radiology and Minimally Invasive Therapy (DeGIR) 2018-2022.

OBJECTIVES: Percutaneous image-guided tumor ablation of liver malignancies has become an indispensable therapeutic procedure. The aim of this evaluation of the prospectively managed multinational registry of the voluntary German Society for Interventional Radiology and Minimally Invasive Therapy (DeGIR) was to analyze its use, technical success, and complications in clinical practice. MATERIALS AND METHODS: All liver tumor ablations from 2018 to 2022 were included. Technical success was defined as complete ablation of the tumor with an ablative margin. RESULTS: A total of 7228 liver tumor ablations from 136 centers in Germany and Austria were analyzed. In total, 31.4% (2268/7228) of patients were female. Median age was 67 years (IQR 58-74 years). Microwave ablation (MWA) was performed in 65.1% (4703/7228), and radiofrequency ablation (RFA) in 32.7% (2361/7228). Of 5229 cases with reported tumor etiology, 60.3% (3152/5229) of ablations were performed for liver metastases and 37.3% (1950/5229) for hepatocellular carcinoma. The median lesion diameter was 19 mm (IQR 12-27 mm). In total, 91.8% (6636/7228) of ablations were technically successful. The rate of technically successful ablations was significantly higher in MWA (93.9%, 4417/4703) than in RFA (87.3%, 2061/2361) (p < 0.0001). The total complication rate was 3.0% (214/7228) and was significantly higher in MWA (4.0%, 189/4703) than in RFA (0.9%, 21/2361, p < 0.0001). Additional needle track ablation did not increase the rate of major complications significantly (24.8% (33/133) vs. 28.4% (23/81), p = 0.56)). CONCLUSION: MWA is the most frequent ablation method. Percutaneous image-guided liver tumor ablations have a high technical success rate, which is higher for MWA than RFA. The complication rate is generally low but is higher for MWA than RFA. CLINICAL RELEVANCE STATEMENT: Percutaneous image-guided liver ablation using microwave ablation and radiofrequency ablation are effective therapeutic procedures with low complication rates for the treatment of primary and secondary liver malignancies. KEY POINTS: • Percutaneous image-guided liver tumor ablations have a high technical success rate, which is higher for microwave ablation than radiofrequency ablation. • Microwave ablation is the most frequent ablation method ahead of radiofrequency ablation. • The complication rate is generally low but is higher for microwave ablation than radiofrequency ablation.

Radiation dose and fluoroscopy time of aneurysm coiling in patients with unruptured and ruptured intracranial aneurysms as a function of aneurysm size, location, and patient age.

PURPOSE: Endovascular treatment of unruptured intracranial aneurysms (UIAs) requires a risk-benefit analysis and adherence to diagnostic reference levels (DRLs). The national DRL (250 Gy·cm2) is only determined for intracranial aneurysm coiling in general, including ruptured intracranial aneurysms (RIAs). This study aims to investigate the dose in the treatment of UIAs and RIAs separately. METHODS: In a retrospective study design, dose area product (DAP) and fluoroscopy time (FT) were assessed for all patients undergoing intracranial aneurysm coiling between 2010 and 2021. DRL was set as the 75th percentile of the dose distribution. A multivariable linear regression analysis was performed to investigate DAP and FT for the two groups, UIA and RIA adjusted for patient age, aneurysm size, and location. RESULTS: 583 (414 females, mean age 56.5 years, 311 UIAs) are included. In the overall population, DAP (median (IQR)) is 157 Gy·cm2 (108-217) with a median FT of 32.7 min (IQR 24.0-47.0). Local DRL is 183 Gy·cm2 for UIAs and 246 Gy·cm2 for RIAs. After adjustment for the other variables, the UIA and RIA groups have a significant effect on both DAP (p < 0.001; 95% CI - 68.432 - - 38.040) and FT (p < 0.001; 95% CI - 628.279 - - 291.254). In general, both DAP and FT increase significantly with patient age and aneurysm size, whereas the location of the aneurysm did not significantly change neither DAP (p = 0.171; 95% CI - 5.537-31.065) nor FT (p = 0.136; 95% CI - 357.391-48.508). CONCLUSION: Both aneurysm size and patient age were associated with increased DAP, whereas aneurysm location did not significantly change DAP or FT. The increased dose in patients with RIAs is likely equivalent to additional diagnostic cerebral four-vessel angiography performed in this group.

Radiation exposure in the endovascular therapy of cranial and spinal dural arteriovenous fistula in the last decade: a retrospective, single-center observational study.

PURPOSE: This study aims to determine local diagnostic reference levels (DRLs) in the endovascular therapy (EVT) of patients with cranial and spinal dural arteriovenous fistula (dAVF). METHODS: In a retrospective study design, DRLs and achievable dose (AD) were assessed for all patients with cranial and spinal dAVF undergoing EVT (I) or diagnostic angiography (II). All procedures were performed at the flat-panel angiography-system Allura Xper (Philips Healthcare). Interventional procedures were differentiated according to the region of fistula and the type of procedure. RESULTS: In total, 264 neurointerventional procedures of 131 patients with dAVF (94 cranial, 37 spinal) were executed between 02/2010 and 12/2020. The following DRLs, AD, and mean values could be determined: for cranial dAVF (I) DRL 507.33 Gy cm2, AD 369.79 Gy cm2, mean 396.51 Gy cm2; (II) DRL 256.65 Gy cm2, AD 214.19 Gy cm2, mean 211.80 Gy cm2; for spinal dAVF (I) DRL 482.72 Gy cm2, AD 275.98 Gy cm2, mean 347.12 Gy cm2; (II) DRL 396.39 Gy cm2, AD 210.57 Gy cm2, mean 299.55 Gy cm2. Dose levels of EVT were significantly higher compared to diagnostic angiographies (p < 0.001). No statistical difference in dose levels regarding the localization of dAVF was found. CONCLUSION: Our results could be used for establishing DRLs in the EVT of cranial and spinal dAVF. Because radiation exposure to comparably complex interventions such as AVM embolization is similar, it may be useful to determine general DRLs for both entities together.

Radiation exposure and establishment of diagnostic reference levels of whole-body low-dose CT for the assessment of multiple myeloma with second- and third-generation dual-source CT.

BACKGROUND: In the assessment of diseases causing skeletal lesions such as multiple myeloma (MM), whole-body low-dose computed tomography (WBLDCT) is a sensitive diagnostic imaging modality, which has the potential to replace the conventional radiographic survey. PURPOSE: To optimize radiation protection and examine radiation exposure, and effective and organ doses of WBLDCT using different modern dual-source CT (DSCT) devices, and to establish local diagnostic reference levels (DRL). MATERIAL AND METHODS: In this retrospective study, 281 WBLDCT scans of 232 patients performed between January 2017 and April 2020 either on a second- (A) or third-generation (B) DSCT device could be included. Radiation exposure indices and organ and effective doses were calculated using a commercially available automated dose-tracking software based on Monte-Carlo simulation techniques. RESULTS: The radiation exposure indices and effective doses were distributed as follows (median, interquartile range): (A) second-generation DSCT: volume-weighted CT dose index (CTDIvol) 1.78 mGy (1.47-2.17 mGy); dose length product (DLP) 282.8 mGy·cm (224.6-319.4 mGy·cm), effective dose (ED) 1.87 mSv (1.61-2.17 mSv) and (B) third-generation DSCT: CTDIvol 0.56 mGy (0.47-0.67 mGy), DLP 92.0 mGy·cm (73.7-107.6 mGy·cm), ED 0.61 mSv (0.52-0.69 mSv). Radiation exposure indices and effective and organ doses were significantly lower with third-generation DSCT (P < 0.001). Local DRLs could be set for CTDIvol at 0.75 mGy and DLP at 120 mGy·cm. CONCLUSION: Third-generation DSCT requires significantly lower radiation dose for WBLDCT than second-generation DSCT and has an effective dose below reported doses for radiographic skeletal surveys. To ensure radiation protection, DRLs regarding WBLDCT are required, where our locally determined values may help as benchmarks.

Diagnostic reference levels for chest computed tomography in children as a function of patient size.

BACKGROUND: Radiation exposures from computed tomography (CT) in children are inadequately studied. Diagnostic reference levels (DRLs) can help optimise radiation doses. OBJECTIVE: To determine local DRLs for paediatric chest CT performed mainly on modern dual-source, multi-slice CT scanners as a function of patient size. MATERIALS AND METHODS: Five hundred thirty-eight chest CT scans in 345 children under 15 years (y) of age (median age: 8 y, interquartile range [IQR]: 4-13 y) performed on four different CT scanners (38% on third-generation and 43% on second-generation dual-source CT) between November 2013 and December 2020 were retrospectively analysed. Examinations were grouped by water-equivalent diameter as a measure of patient size. DRLs for volume CT dose index (CTDIvol) and dose-length product (DLP) were determined for six different patient sizes and compared to national and European DRLs. RESULTS: The DRLs for CTDIvol and DLP are determined for each patient size group as a function of water-equivalent diameter as follows: (I) < 13 cm (n = 22; median: age 7 months): 0.4 mGy, 7 mGy·cm; (II) 13 cm to less than 17 cm (n = 151; median: age 3 y): 1.2 mGy, 25 mGy·cm; (III) 17 cm to less than 21 cm (n = 211; median: age 8 y): 1.7 mGy, 44 mGy·cm; (IV) 21 cm to less than 25 cm (n = 97; median: age 14 y): 3.0 mGy, 88 mGy·cm; (V) 25 cm to less than 29 cm (n = 42; median: age 14 y): 4.5 mGy, 135 mGy·cm; (VI) ≥ 29 cm (n = 15; median: age 14 y): 8.0 mGy, 241 mGy·cm. Compared with corresponding age and weight groups, our size-based DRLs for DLP are 54% to 71% lower than national and 23% to 85% lower than European DRLs. CONCLUSION: We developed DRLs for paediatric chest CT as a function of patient size with substantially lower values than national and European DRLs. Precise knowledge of size-based DRLs may assist other institutions in further dose optimisation in children.

Radiation dose aspects and establishment of diagnostic reference levels for90Y radioembolisation during angiographic procedure.

90Y radioembolisation (RE) is an angiographic procedure used in patients with both primary and secondary hepatic malignancies. Local tumour control can be achieved by short range tumour irradiation by the regional intra-arterial administration of glass or resin microspheres loaded with 90yttrium that accumulate in the tumorous tissue. The aim of this study was to investigate the radiation exposure of RE and to establish a local diagnostic reference level (DRL). In this retrospective study, dose data from 397 procedures in 306 patients (mean age 67.4 ± 10.6 years, 82 female) who underwent RE between 06/2017 and 01/2022 using one of two different angiography systems were analysed. DRL was set as the 75th percentile of the dose distribution. In the overall population, dose area product (DAP) (median (interquartile range, IQR)) was 26 Gy cm2(IQR 12-50) with a median fluoroscopy time (FT) of 4.5 min (IQR 2.9-8.0). FT and DAP increased significantly with the number of infusion positions (median, IQR): one position 23 Gy cm2(12-46), two positions 33 Gy cm2(14-60), three positions 50 Gy cm2(24-82) (p< 0.0001). Local DRL is 47 Gy cm2for RE and 111 Gy cm2for RE with additional embolisation. Radiation exposure and FT are significantly higher with increasing number of infusion positions as well as additional embolisation. Our established DRLs for RE may serve as a benchmark for dose optimisation.

Radiation exposure, organ and effective dose of CT-guided liver biopsy as a function of lesion depth and size.

Computed tomography (CT)-guided percutaneous biopsies play an important role in the diagnostic workup of liver lesions. Because radiation dose accumulates rapidly due to repeated image acquisition in a relatively small scan area, analysing radiation exposure is critical for improving radiation protection of CT-guided interventions. The aim of this study was to assess the radiation dose of CT-guided liver biopsies and the influence of lesion parameters, and to establish a local diagnostic reference level (DRL). In this observational retrospective cohort study, dose data of 60 CT-guided liver biopsies between September 2016 and July 2017 were analysed. Radiation exposure was reported for volume-weighted CT dose index (CTDIvol), size-specific dose estimate (SSDE), dose-length product (DLP) and effective dose (ED). Radiation dose of CT-guided liver biopsy was (median (interquartile range)): CTDIvol9.91 mGy (8.33-11.45 mGy), SSDE 10.42 mGy (9.39-11.70 mGy), DLP 542 mGy cm (410-733 mGy cm), ED 8.52 mSv (7.17-13.25 mSv). Radiation exposure was significantly higher in biopsies of deep liver lesions compared to superficial lesions (DLP 679 ± 285 mGy cm vs. 497 ± 167 mGy cm,p= 0.0046). No significant dose differences were observed for differences in lesion or needle size. With helical CT spirals additional to the biopsy-guiding axial CT scans, radiation exposure was significantly increased: 797 ± 287 mGy cm vs. 495 ± 162 mGy cm,p< 0.0001. The local DRL is CTDIvol9.91 mGy, DLP 542 mGy cm. Radiation dose is significantly increased in biopsies of deeper liver lesions compared with superficial lesions. Interventions with additional biopsy-guiding CT spirals lead to higher radiation doses. This study provides a detailed analysis of local radiation doses for CT-guided liver biopsies and provides a benchmark for optimising radiation protection in interventional radiology.

Radiation exposure in the intra-arterial nimodipine therapy of subarachnoid hemorrhage related cerebral vasospasm.

The selective intra-arterial nimodipine application for the treatment of cerebral vasospasm (CVS) in patients after spontaneous subarachnoid hemorrhage (sSAH) is widely employed. The purpose of this study is to examine the radiation exposure and to determine local diagnostic reference levels (DRLs) of intra-arterial nimodipine therapy. In a retrospective study design, DRLs and achievable dose (AD) were assessed for all patients undergoing (I) selective intra-arterial nimodipine application or (II) additional mechanical angioplasty for CVS treatment. Interventional procedures were differentiated according to the type of procedure and the number of probed vessels. Altogether 494 neurointerventional procedures of 121 patients with CVS due to sSAH could be included. The radiation exposure indices were distributed as follows: (I) DRL 74.3 Gy·cm2, AD 59.8 Gy·cm2; (II) DRL 128.3 Gy·cm2, AD 94.5 Gy·cm2. Kruskal-Wallis test confirmed significant dose difference considering the number of probed vessels (p< 0.001). The mean cumulative dose per patient was 254.9 Gy·cm2(interquartile range 88.6-315.6 Gy·cm2). The DRLs of intra-arterial nimodipine therapy are substantially lower compared with DRLs proposed for other therapeutic interventions, such as thrombectomy or aneurysm coiling. However, repeated therapy sessions are often required, bearing the potential risk of a cumulatively higher radiation exposure.

Radiation exposure of computed tomography imaging for the assessment of acute stroke.

PURPOSE: To assess suspected acute stroke, the computed tomography (CT) protocol contains a non-contrast CT (NCCT), a CT angiography (CTA), and a CT perfusion (CTP). Due to assumably high radiation doses of the complete protocol, the aim of this study is to examine radiation exposure and to establish diagnostic reference levels (DRLs). METHODS: In this retrospective study, dose data of 921 patients with initial CT imaging for suspected acute stroke and dose monitoring with a DICOM header-based tracking and monitoring software were analyzed. Between June 2017 and January 2020, 1655 CT scans were included, which were performed on three different modern multi-slice CT scanners, including 921 NCCT, 465 CTA, and 269 CTP scans. Radiation exposure was reported for CT dose index (CTDIvol) and dose-length product (DLP). DRLs were set at the 75th percentile of dose distribution. RESULTS: DRLs were assessed for each step (CTDIvol/DLP): NCCT 33.9 mGy/527.8 mGy cm and CTA 13.7 mGy/478.3 mGy cm. Radiation exposure of CTP was invariable and depended on CT device and its protocol settings with CTDIvol 124.9-258.2 mGy and DLP 1852.6-3044.3 mGy cm. CONCLUSION: Performing complementary CT techniques such as CTA and CTP for the assessment of acute stroke increases total radiation exposure. Hence, the revised DRLs for the complete protocol are required, where our local DRLs may help as benchmarks.

Estimation of radiation exposure of children undergoing superselective intra-arterial chemotherapy for retinoblastoma treatment: assessment of local diagnostic reference levels as a function of age, sex, and interventional success.

PURPOSE: This study aims to determine local diagnostic reference levels (LDRLs) of intra-arterial chemotherapy (IAC) procedures of pediatric patients with retinoblastoma (RB) to provide data for establishing diagnostic reference levels (DRLs) in pediatric interventional radiology (IR). METHODS: In a retrospective study design, LDRLs and achievable dose (AD) were assessed for children undergoing superselective IAC for RB treatment. All procedures were performed at the flat-panel angiography systems (I) ArtisQ biplane (Siemens Healthineers) and (II) Allura Xper (Philips Healthcare). Patients were differentiated according to age (A1: 1-3 months; A2: 4-12 months; A3: 13-72 months; A4: 73 months-10 years; A5: > 10 years), sex, conducted or not-conducted chemotherapy. RESULTS: 248 neurointerventional procedures of 130 pediatric patients (median age 14.5 months, range 5-127 months) with RB (68 unilateral, 62 bilateral) could be included between January 2010 and March 2020. The following diagnostic reference values, AD, and mean values could be determined: (A2) DRL 3.9 Gy cm2, AD 2.9 Gy cm2, mean 3.5 Gy cm2; (A3) DRL 7.0 Gy cm2, AD 4.3 Gy cm2, mean 6.0 Gy cm2; (A4) DRL 14.5 Gy cm2, AD 10.7 Gy cm2, mean 10.8 Gy cm2; (A5) AD 8.8 Gy cm2, mean 8.8 Gy cm2. Kruskal-Wallis-test confirmed a significant dose difference between the examined age groups (A2-A5) (p < 0.001). There was no statistical difference considering sex (p = 0.076) and conducted or not-conducted chemotherapy (p = 0.627). A successful procedure was achieved in 207/248 cases. CONCLUSION: We report on radiation exposure during superselective IAC of a pediatric cohort at the German Retinoblastoma Referral Centre. Although an IAC formally represents a therapeutic procedure, our results confirm that radiation exposure lies within the exposure of a diagnostic interventional procedure. DRLs for superselective IAC are substantially lower compared with DRLs of more complex endovascular interventions.

Experimental examination of radiation doses from cardiac and liver CT perfusion in a phantom study as a function of organ, age and sex.

Cardiac and liver computed tomography (CT) perfusion has not been routinely implemented in the clinic and requires high radiation doses. The purpose of this study is to examine the radiation exposure and technical settings for cardiac and liver CT perfusion scans at different CT scanners. Two cardiac and three liver CT perfusion protocols were examined with the N1 LUNGMAN phantom at three multi-slice CT scanners: a single-source (I) and second- (II) and third-generation (III) dual-source CT scanners. Radiation doses were reported for the CT dose index (CTDIvol) and dose-length product (DLP) and a standardised DLP (DLP10cm) for cardiac and liver perfusion. The effective dose (ED10cm) for a standardised scan length of 10 cm was estimated using conversion factors based on the International Commission on Radiological Protection (ICRP) 110 phantoms and tissue-weighting factors from ICRP 103. The proposed total lifetime attributable risk of developing cancer was determined as a function of organ, age and sex for adults. Radiation exposure for CTDIvol, DLP/DLP10 cmand ED10 cmduring CT perfusion was distributed as follows: for cardiac perfusion (II) 144 mGy, 1036 mGy·cm/1440 mGy·cm and 39 mSv, and (III) 28 mGy, 295 mGy·cm/279 mGy·cm and 8 mSv; for liver perfusion (I) 225 mGy, 3360 mGy·cm/2249 mGy·cm and 54 mSv, (II) 94 mGy, 1451 mGy·cm/937 mGy·cm and 22 mSv, and (III) 74 mGy, 1096 mGy·cm/739 mGy·cm and 18 mSv. The third-generation dual-source CT scanner applied the lowest doses. Proposed total lifetime attributable risk increased with decreasing age. Even though CT perfusion is a high-dose examination, we observed that new-generation CT scanners could achieve lower doses. There is a strong impact of organ, age and sex on lifetime attributable risk. Further investigations of the feasibility of these perfusion scans are required for clinical implementation.

Impact of CT and MRI in the diagnostic workup of malignant triton tumour-a monocentric analysis and review of the literature.

OBJECTIVES: Malignant triton tumours (MTTs) are rare but aggressive subtypes of malignant peripheral nerve sheath tumours (MPNSTs) with a high recurrence rate and 5-year survival of 14%. Systematic imaging data on MTTs are scarce and mainly based on single case reports. Therefore, we aimed to identify typical CT and MRI features to improve early diagnosis rates of this uncommon entity. METHODS: A systematic review on literature published until December 2022 on imaging characteristics of MTTs was performed. Based on that, we conducted a retrospective, monocentric analysis of patients with histopathologically proven MTTs from our department. Explorative data analysis was performed. RESULTS: Initially, 29 studies on 34 patients (31.42 ± 22.6 years, 12 female) were evaluated: Literature described primary MTTs as huge, lobulated tumours (108 ± 99.3 mm) with central necrosis (56% [19/34]), low T1w (81% [17/21]), high T2w signal (90% [19/21]) and inhomogeneous enhancement on MRI (54% [7/13]). Analysis of 16 patients (48.9 ± 13.8 years; 9 female) from our institution revealed comparable results: primary MTTs showed large, lobulated masses (118 mm ± 64.9) with necrotic areas (92% [11/12]). MRI revealed low T1w (100% [7/7]), high T2w signal (100% [7/7]) and inhomogeneous enhancement (86% [6/7]). Local recurrences and soft-tissue metastases mimicked these features, while nonsoft-tissue metastases appeared unspecific. CONCLUSIONS: MTTs show characteristic features on CT and MRI. However, these do not allow a reliable differentiation between MTTs and other MPNSTs based on imaging alone. Therefore, additional histopathological analysis is required. ADVANCES IN KNOWLEDGE: This largest published systematic analysis on MTT imaging revealed typical but unspecific imaging features that do not allow a reliable, imaging-based differentiation between MTTs and other MPNSTs. Hence, additional histopathological analysis remains essential.

Impact of AI-Based Post-Processing on Image Quality of Non-Contrast Computed Tomography of the Chest and Abdomen.

Non-contrast computed tomography (CT) is commonly used for the evaluation of various pathologies including pulmonary infections or urolithiasis but, especially in low-dose protocols, image quality is reduced. To improve this, deep learning-based post-processing approaches are being developed. Therefore, we aimed to compare the objective and subjective image quality of different reconstruction techniques and a deep learning-based software on non-contrast chest and low-dose abdominal CTs. In this retrospective study, non-contrast chest CTs of patients suspected of COVID-19 pneumonia and low-dose abdominal CTs suspected of urolithiasis were analysed. All images were reconstructed using filtered back-projection (FBP) and were post-processed using an artificial intelligence (AI)-based commercial software (PixelShine (PS)). Additional iterative reconstruction (IR) was performed for abdominal CTs. Objective and subjective image quality were evaluated. AI-based post-processing led to an overall significant noise reduction independent of the protocol (chest or abdomen) while maintaining image information (max. difference in SNR 2.59 ± 2.9 and CNR 15.92 ± 8.9, p < 0.001). Post-processing of FBP-reconstructed abdominal images was even superior to IR alone (max. difference in SNR 0.76 ± 0.5, p ≤ 0.001). Subjective assessments verified these results, partly suggesting benefits, especially in soft-tissue imaging (p < 0.001). All in all, the deep learning-based denoising-which was non-inferior to IR-offers an opportunity for image quality improvement especially in institutions using older scanners without IR availability. Further studies are necessary to evaluate potential effects on dose reduction benefits.

Assessment of image quality and impact of deep learning-based software in non-contrast head CT scans.

In this retrospective study, we aimed to assess the objective and subjective image quality of different reconstruction techniques and a deep learning-based software on non-contrast head computed tomography (CT) images. In total, 152 adult head CT scans (77 female, 75 male; mean age 69.4 ± 18.3 years) obtained from three different CT scanners using different protocols between March and April 2021 were included. CT images were reconstructed using filtered-back projection (FBP), iterative reconstruction (IR), and post-processed using a deep learning-based algorithm (PS). Post-processing significantly reduced noise in FBP-reconstructed images (up to 15.4% reduction) depending on the protocol, leading to improvements in signal-to-noise ratio of up to 19.7%. However, when deep learning-based post-processing was applied to FBP images compared to IR alone, the differences were inconsistent and partly non-significant, which appeared to be protocol or site specific. Subjective assessments showed no significant overall improvement in image quality for all reconstructions and post-processing. Inter-rater reliability was low and preferences varied. Deep learning-based denoising software improved objective image quality compared to FBP in routine head CT. A significant difference compared to IR was observed for only one protocol. Subjective assessments did not indicate a significant clinical impact in terms of improved subjective image quality, likely due to the low noise levels in full-dose images.

Elexacaftor/tezacaftor/ivacaftor influences body composition in adults with cystic fibrosis: a fully automated CT-based analysis.

A poor nutritional status is associated with worse pulmonary function and survival in people with cystic fibrosis (pwCF). CF transmembrane conductance regulator modulators can improve pulmonary function and body weight, but more data is needed to evaluate its effects on body composition. In this retrospective study, a pre-trained deep-learning network was used to perform a fully automated body composition analysis on chest CTs from 66 adult pwCF before and after receiving elexacaftor/tezacaftor/ivacaftor (ETI) therapy. Muscle and adipose tissues were quantified and divided by bone volume to obtain body size-adjusted ratios. After receiving ETI therapy, marked increases were observed in all adipose tissue ratios among pwCF, including the total adipose tissue ratio (+ 46.21%, p < 0.001). In contrast, only small, but statistically significant increases of the muscle ratio were measured in the overall study population (+ 1.63%, p = 0.008). Study participants who were initially categorized as underweight experienced more pronounced effects on total adipose tissue ratio (p = 0.002), while gains in muscle ratio were equally distributed across BMI categories (p = 0.832). Our findings suggest that ETI therapy primarily affects adipose tissues, not muscle tissue, in adults with CF. These effects are primarily observed among pwCF who were initially underweight. Our findings may have implications for the future nutritional management of pwCF.

Body composition impacts outcome of bronchoscopic lung volume reduction in patients with severe emphysema: a fully automated CT-based analysis.

Chronic Obstructive Pulmonary Disease (COPD) is characterized by progressive and irreversible airflow limitation, with individual body composition influencing disease severity. Severe emphysema worsens symptoms through hyperinflation, which can be relieved by bronchoscopic lung volume reduction (BLVR). To investigate how body composition, assessed through CT scans, impacts outcomes in emphysema patients undergoing BLVR. Fully automated CT-based body composition analysis (BCA) was performed in patients with end-stage emphysema receiving BLVR with valves. Post-interventional muscle and adipose tissues were quantified, body size-adjusted, and compared to baseline parameters. Between January 2015 and December 2022, 300 patients with severe emphysema underwent endobronchial valve treatment. Significant improvements were seen in outcome parameters, which were defined as changes in pulmonary function, physical performance, and quality of life (QoL) post-treatment. Muscle volume remained stable (1.632 vs. 1.635 for muscle bone adjusted ratio (BAR) at baseline and after 6 months respectively), while bone adjusted adipose tissue volumes, especially total and pericardial adipose tissue, showed significant increase (2.86 vs. 3.00 and 0.16 vs. 0.17, respectively). Moderate to strong correlations between bone adjusted muscle volume and weaker correlations between adipose tissue volumes and outcome parameters (pulmonary function, QoL and physical performance) were observed. Particularly after 6-month, bone adjusted muscle volume changes positively corresponded to improved outcomes (ΔForced expiratory volume in 1 s [FEV1], r = 0.440; ΔInspiratory vital capacity [IVC], r = 0.397; Δ6Minute walking distance [6MWD], r = 0.509 and ΔCOPD assessment test [CAT], r = -0.324; all p < 0.001). Group stratification by bone adjusted muscle volume changes revealed that groups with substantial muscle gain experienced a greater clinical benefit in pulmonary function improvements, QoL and physical performance (ΔFEV1%, 5.5 vs. 39.5; ΔIVC%, 4.3 vs. 28.4; Δ6MWDm, 14 vs. 110; ΔCATpts, -2 vs. -3.5 for groups with ΔMuscle, BAR% < -10 vs. > 10, respectively). BCA results among patients divided by the minimal clinically important difference for forced expiratory volume of the first second (FEV1) showed significant differences in bone-adjusted muscle and intramuscular adipose tissue (IMAT) volumes and their respective changes after 6 months (ΔMuscle, BAR% -5 vs. 3.4 and ΔIMAT, BAR% -0.62 vs. 0.60 for groups with ΔFEV1 ≤ 100 mL vs > 100 mL). Altered body composition, especially increased muscle volume, is associated with functional improvements in BLVR-treated patients.

Radiation Exposure in Computed Tomography.

BACKGROUND: Computed tomography (CT) studies are requested by specialists from most medical disciplines and play a vital role in the diagnosis and treatment of patients. It follows that physicians of all specialties should possess basic knowledge of computed tomography, its proper use, and the radiation exposure associated with it. METHODS: This review is based on publications retrieved by a selective search of the literature. RESULTS: Approximately 12 million CT studies are carried out in Germany each year, and the trend is rising. Approximately 9% of all diagnostic studies involving ionizing radiation are CT studies. On average, more than 60% of the collective effective dose due to medical radiation exposure is attributable to CT. There are two types of radiation effects caused by ionizing radiation: sto - chastic and deterministic. The additional, individual relative lifetime cancer mortality risk due to ionizing radiation with wholebody exposure at a low single dose is estimated at 5% per sievert. Radiation exposure from CT studies of the head and trunk, e.g. of a patient with polytrauma, corresponds to an additional lifetime cancer mortality risk of approximately 0.1% at an effective dose of approximately 20 millisievert. CONCLUSION: The radiation exposure due to CT, and the risks to which patients are subjected by it, have become more important with greater use of CT. Technical advances, targeted dose monitoring, and analyses of dose data can help identify areas where improvement is necessary, in furtherance of the overriding goal of lowering patients' radiation exposure while preserving adequate image quality.

Unspecific 18F-PSMA-1007 Bone Uptake Evaluated Through PSMA-11 PET, Bone Scanning, and MRI Triple Validation in Patients with Biochemical Recurrence of Prostate Cancer.

18F-PSMA-1007 PET is used in the management of patients with prostate cancer. However, recent reports indicate a high rate of unspecific bone uptake (UBU) with 18F-PSMA-1007, which may lead to a false-positive diagnosis. UBU has not been evaluated thoroughly. Here, we evaluate the frequency of UBU and bone metastases separately for 18F-PSMA-1007 and 68Ga-PSMA-11 in biochemical recurrence (interindividual comparison). Additionally, we investigate UBU seen in 18F-PSMA-1007 through follow-up examinations (intraindividual comparison) using 68Ga-PSMA-11 PET, bone scintigraphy, and MRI. Methods: First, all patients (n = 383) who underwent 68Ga-PSMA-11 PET between January 2020 and December 2020 and all patients (n = 409) who underwent 18F-PSMA-1007 PET between January 2020 and November 2021 due to biochemical recurrence were included for an interindividual comparison of bone metastases and UBU rate. In a second approach, we regarded all patients with UBU in 18F-PSMA-1007, characterized by focal bone uptake with an SUVmax > 4 and prostate-specific antigen (PSA) ≤ 5 ng/mL, who underwent additional 68Ga-PSMA-11 PET (n = 17) (interindividual comparison). Of these, 12 patients also had bone scintigraphy and whole-body MRI within a 1- to 5-wk interval. Bone uptake seen on 18F-PSMA-1007 but not on any of the other 4 modalities (CT, MRI [n = 1], bone scanning, and 68Ga-PSMA-11 PET) was recorded as false-positive. Results: Patients scanned with 18F-PSMA-1007 PET had a significantly higher rate of UBU than those scanned with 68Ga-PSMA-11 (140 vs. 64; P < 0.001); however, the rate of bone metastases was not significantly different (72 vs. 64; P = 0.7). In the intraindividual comparison group, workup by CT, MRI, bone scanning, and 68Ga-PSMA-11 PET resulted in a positive predictive value for 18F-PSMA-1007 focal bone uptake (mean SUVmax, 6.1 ± 2.9) per patient and per lesion of 8.3% and 3.6%, respectively. Conclusion: In patients with PSA ≤ 5 ng/mL and SUV > 4 at biochemical recurrence, most 18F-PSMA-1007 focal bone uptake is likely to be false-positive and therefore due to UBU. In the case of low clinical likelihood of metastatic disease, 18F-PSMA-1007 bone uptake without morphologic surrogate should be assessed carefully with regard to localization and clinical context. However, the rate of bone metastases was not higher with 18F-PSMA-1007 in the clinical routine, indicating that experienced reporting physicians adjust for UBU findings.