European Radiology最新文献

Objectives: To evaluate the robustness of radiomics features among photon-counting detector CT (PCD-CT) and dual-energy CT (DECT) systems.

Methods: A texture phantom consisting of twenty-eight materials was scanned with one PCD-CT and four DECT systems (dual-source, rapid kV-switching, dual-layer, and sequential scanning) at three dose levels twice. Thirty sets of virtual monochromatic images at 70 keV were reconstructed. Regions of interest were delineated for each material with a rigid registration. Ninety-three radiomics were extracted per PyRadiomics. The test-retest repeatability between repeated scans was assessed by Bland-Altman analysis. The intra-system reproducibility between dose levels, and inter-system reproducibility within the same dose level, were evaluated by intraclass correlation coefficient (ICC) and concordance correlation coefficient (CCC). Inter-system variability among five scanners was assessed by coefficient of variation (CV) and quartile coefficient of dispersion (QCD).

Results: The test-retest repeatability analysis presented that 97.1% of features were repeatable between scan-rescans. The mean ± standard deviation ICC and CCC were 0.945 ± 0.079 and 0.945 ± 0.079 for intra-system reproducibility, respectively, and 86.0% and 85.7% of features were with ICC > 0.90 and CCC > 0.90, respectively, between different dose levels. The mean ± standard deviation ICC and CCC were 0.157 ± 0.174 and 0.157 ± 0.174 for inter-system reproducibility, respectively, and none of the features were with ICC > 0.90 or CCC > 0.90 within the same dose level. The inter-system variability suggested that 6.5% and 12.8% of features were with CV < 10% and QCD < 10%, respectively, among five CT systems.

Conclusion: The radiomics features were non-reproducible with significant variability in values among different CT techniques.

Clinical relevance statement: Radiomics features are non-reproducible with significant variability in values among photon-counting detector CT and dual-energy CT systems, necessitating careful attention to improve the cross-system generalizability of radiomic features before implementation of radiomics analysis in clinical routine.

Key points: CT radiomics stability should be guaranteed before the implementation in the clinical routine. Radiomics robustness was on a low level among photon-counting detectors and dual-energy CT techniques. Limited inter-system robustness of radiomic features may impact the generalizability of models.

Objectives: Differentiating true progression or recurrence (TP/TR) from therapy-related changes (TRC) is complex in brain tumours. Amide proton transfer-weighted (APT) imaging is a chemical exchange saturation transfer (CEST) MRI technique that may improve diagnostic accuracy during radiological follow-up. This systematic review and meta-analysis elucidated the level of evidence and details of state-of-the-art imaging for APT-CEST in glioma and brain metastasis surveillance.

Methods: PubMed, EMBASE, Web of Science, and Cochrane Library were systematically searched for original articles about glioma and metastasis patients who received APT-CEST imaging for suspected TP/TR within 2 years after (chemo)radiotherapy completion. Modified Quality Assessment of Diagnostic Accuracy Studies-2 criteria were applied. A meta-analysis was performed to pool results and to compare subgroups.

Results: Fifteen studies were included for a narrative synthesis, twelve of which (500 patients) were deemed sufficiently homogeneous for a meta-analysis. Magnetisation transfer ratio asymmetry performed well in gliomas (sensitivity 0.88 [0.82-0.92], specificity 0.84 [0.72-0.91]) but not in metastases (sensitivity 0.64 [0.38-0.84], specificity 0.56 [0.33-0.77]). APT-CEST combined with conventional/advanced MRI rendered 0.92 [0.86-0.96] and 0.88 [0.72-0.95] in gliomas. Tumour type, TR prevalence, sex, and acquisition protocol were sources of significant inter-study heterogeneity in sensitivity (I² = 62.25%; p < 0.01) and specificity (I² = 66.31%; p < 0.001).

Conclusion: A growing body of literature suggests that APT-CEST is a promising technique for improving the discrimination of TP/TR from TRC in gliomas, with limited data on metastases.

Clinical relevance statement: This meta-analysis identified a utility for APT-CEST imaging regarding the non-invasive discrimination of brain tumour progression from therapy-related changes, providing a critical evaluation of sequence parameters and cut-off values, which can be used to improve response assessment and patient outcome.

Key points: Therapy-related changes mimicking progression complicate brain tumour treatment. Amide proton imaging improves the non-invasive discrimination of glioma progression from therapy-related changes. Magnetisation transfer ratio asymmetry measurement seems not to have added value in brain metastases.

Objective: Ultrasound-guided thermal ablation, including radiofrequency ablation (RFA) and microwave ablation (MWA), has become one of the main options for treating benign thyroid nodules (BTNs). To assess the efficacy of thermal ablation of BTNs, we performed a systematic review and meta-analysis of relevant studies.

Materials and methods: A comprehensive search of MEDLINE, EMBASE, and COCHRANE databases was performed up to September 25, 2023, to identify studies directly comparing RFA and MWA for pathologically proven BTNs and reporting clinical outcomes and complications. Data extraction and quality assessment were independently performed by two radiologists according to PRISMA guidelines. The analysis yielded the serial volume reduction ratios (VRRs) of ablated nodules for up to 12 months, symptom and cosmetic scores, and complications.

Results: This analysis included nine studies with 1305 BTNs treated by RFA and 1276 by MWA. VRRs at 1 month, 3 months, and 6 months were similar between RFA and MWA, but RFA showed a significantly higher VRR (83.3%) than MWA (76.9%) at 12 months (p = 0.02). Complication rates showed no significant difference between the two methods. Symptom and cosmetic scores significantly decreased after ablation, without a significant difference between the methods. Subgroup analysis indicated a significantly higher VRR at 12 months for RFA than for MWA for less experienced investigators (≤ 10 years), but no significant difference for more experienced investigators (> 10 years).

Conclusion: RFA and MWA are both effective and safe methods for treating BTNs. RFA showed a higher VRR at 12 months and seems more suitable for less experienced investigators.

Clinical relevance statement: RFA and MWA are both effective and safe treatments for BTNs, with RFA showing a higher VRR at 12 months. Both methods offer minimally invasive and reliable treatment for thyroid nodules.

Key points: The most effective thermal ablation technique for BTNs remains undetermined. RFA showed a higher VRR at 12 months than MWA. Both techniques are effective for treating thyroid nodules; RFA offers greater benefits, particularly for less experienced investigators.

Objectives: To explore diffusion-weighted imaging (DWI), intravoxel incoherent motion (IVIM), and diffusion kurtosis imaging (DKI) for assessing pathological prognostic factors in patients with rectal cancer.

Materials and methods: A total of 162 patients (105 males; mean age of 61.8 ± 13.1 years old) scheduled to undergo radical surgery were enrolled in this prospective study. The pathological prognostic factors included histological differentiation, lymph node metastasis (LNM), and extramural vascular invasion (EMVI). The DWI, IVIM, and DKI parameters were obtained and correlated with prognostic factors using univariable and multivariable logistic regression. Their assessment value was evaluated using receiver operating characteristic (ROC) curve analysis.

Results: Multivariable logistic regression analyses showed that higher mean kurtosis (MK) (odds ratio (OR) = 194.931, p < 0.001) and lower apparent diffusion coefficient (ADC) (OR = 0.077, p = 0.025) were independently associated with poorer differentiation tumors. Higher perfusion fraction (f) (OR = 575.707, p = 0.023) and higher MK (OR = 173.559, p < 0.001) were independently associated with LNMs. Higher f (OR = 1036.116, p = 0.024), higher MK (OR = 253.629, p < 0.001), lower mean diffusivity (MD) (OR = 0.125, p = 0.038), and lower ADC (OR = 0.094, p = 0.022) were independently associated with EMVI. The area under the ROC curve (AUC) of MK for histological differentiation was significantly higher than ADC (0.771 vs. 0.638, p = 0.035). The AUC of MK for LNM positivity was higher than f (0.770 vs. 0.656, p = 0.048). The AUC of MK combined with MD (0.790) was the highest among f (0.663), MK (0.779), MD (0.617), and ADC (0.610) in assessing EMVI.

Conclusion: The DKI parameters may be used as imaging biomarkers to assess pathological prognostic factors of rectal cancer before surgery.

Clinical relevance statement: Diffusion kurtosis imaging (DKI) parameters, particularly mean kurtosis (MK), are promising biomarkers for assessing histological differentiation, lymph node metastasis, and extramural vascular invasion of rectal cancer. These findings suggest DKI's potential in the preoperative assessment of rectal cancer.

Key points: Mean kurtosis outperformed the apparent diffusion coefficient in assessing histological differentiation in resectable rectal cancer. Perfusion fraction and mean kurtosis are independent indicators for assessing lymph node metastasis in rectal cancer. Mean kurtosis and mean diffusivity demonstrated superior accuracy in assessing extramural vascular invasion.

Assessing the response to oncological treatments is paramount for determining the prognosis and defining the best treatment for each patient. Several biomarkers, including imaging, can be used, but standardization is fundamental for consistency and reliability. Tumor response evaluation criteria have been defined by international groups for application in pharmaceutical clinical trials evaluating new drugs or therapeutic strategies. RECIST 1.1 criteria are exclusively based on unidimensional lesion measurements; changes in tumor size are used as surrogate imaging biomarkers to correlate with patient outcomes. However, increased tumor size does not always reflect tumor progression. The introduction of immunotherapy has led to the development of new criteria (iRECIST, Level of Evidence (LoE) Ib) that consider the possibility that an increase in disease burden is secondary to the immune response instead of progression, with the new concept of Unconfirmed Progressive Disease (a first progression event which must be confirmed on follow-up). Specific criteria were devised for HCC (mRECIST, LoE IV), which measure only enhancing HCC portions to account for changes after local therapy. For GIST treated with imatinib, criteria were developed to account for the possible increase in size reflecting a response rather than a progression by assessing both tumor size and density on CT (Choi, LoE II). This article provides concise and relevant practice recommendations aimed at general radiologists to help choose and apply the most appropriate criteria for assessing response to treatment in different oncologic scenarios. Though these criteria were developed for clinical trials, they may be applied in clinical practice as a guide for day-to-day interpretation. KEY POINTS: Response evaluation criteria, designed for use in clinical trials, might serve as a surrogate biomarker for overall survival. RECIST 1.1 defines measurable and non-measurable disease among which target lesions and non-target lesions are selected at baseline as reference for follow-ups. Some therapies and/or cancers require the use of different criteria, such as iRECIST, mRECIST, and Choi criteria.

Objective: Combining fluoroscopy and high-resolution cone-beam CT (CBCT) in a multipurpose scanner without a conventional gantry holds the potential for time-saving in musculoskeletal interventions. This study investigated the performance of gantry-free CBCT arthrography in patients with suspected scapholunate ligament (SLL) tears.

Materials and methods: Fifty-five patients (29 men, 46.0 ± 15.3 years) who underwent preoperative gantry-free CBCT arthrography between June 2021 and March 2024 were analyzed retrospectively. Three radiologists assessed CBCT arthrograms for tears of the palmar and dorsal SLL segments. Surgical reports served as the reference standard for calculating indicators of diagnostic accuracy. Interreader agreement was tested by computing Krippendorff α. Radiation dose and examination time were recorded.

Results: Tears of the palmar and dorsal SLL segment were recorded in 25 (45%) and 6 patients (11%), respectively. CBCT arthrography facilitated good sensitivity (range for all readers: 84-92%) and excellent specificity (93-97%) in the assessment of the palmar SLL. For the dorsal SLL, sensitivity (83-100%) and specificity (96-98%) were even higher. Substantial agreement was determined for both the palmar (α = 0.83, 95% CI: 0.74-0.90) and dorsal SLL (0.84, 0.70-0.95). The mean volume CT dose index for CBCT arthrography was 3.2 ± 1.4 mGy. Not requiring patient repositioning, the median time between fluoroscopy-guided contrast injection and CBCT was 3:05 min (2:31-3:50 min).

Conclusion: Gantry-free CBCT arthrography allows for excellent accuracy in the preoperative diagnosis of SLL tears with low radiation dose. The ability to alternate between fluoroscopy and CBCT without repositioning facilitates a "one-stop-shop" approach with short examination time.

Key points: Question Performing fluoroscopy-guided arthrography and high-resolution cone-beam CT without patient repositioning appears advantageous for the preoperative work-up of distal radius fractures with concomitant scapholunate ligament injuries. Findings Gantry-free cone-beam CT arthrography allowed for short examination times and high diagnostic accuracy for either segment of the scapholunate ligament (89-98% versus surgery). Clinical relevance Preoperative assessment of scapholunate instability influences treatment since surgeons can reduce radius fractures and perform osteosynthesis via a dorsal portal to simultaneously stabilize the scapholunate compartment or use an additional dorsal access route for ligament suture and transfixation.

Objectives: This study aims to externally validate a commercially available Computer-Aided Detection (CAD)-system for the automatic detection and characterization of solid, part-solid, and ground-glass lung nodules (LN) on CT scans.

Methods: This retrospective study encompasses 263 chest CT scans performed between January 2020 and December 2021 at a Dutch university hospital. All scans were read by a radiologist (R1) and compared with the initial radiology report. Conflicting scans were assessed by an adjudicating radiologist (R2). All scans were also processed by CAD. The standalone performance of CAD in terms of sensitivity and false-positive (FP)-rate for detection was calculated together with the sensitivity for characterization, including texture, calcification, speculation, and location. The R1's detection sensitivity was also assessed.

Results: A total of 183 true nodules were identified in 121 nodule-containing scans (142 non-nodule-containing scans), of which R1 identified 165/183 (90.2%). CAD detected 149 nodules, of which 12 were not identified by R1, achieving a sensitivity of 149/183 (81.4%) with an FP-rate of 49/121 (0.405). CAD's detection sensitivity for solid, part-solid, and ground-glass LNs was 82/94 (87.2%), 42/47 (89.4%), and 25/42 (59.5%), respectively. The classification accuracy for solid, part-solid, and ground-glass LNs was 81/82 (98.8%), 16/42 (38.1%), and 18/25 (72.0%), respectively. Additionally, CAD demonstrated overall classification accuracies of 137/149 (91.9%), 123/149 (82.6%), and 141/149 (94.6%) for calcification, spiculation, and location, respectively.

Conclusions: Although the overall detection rate of this system slightly lags behind that of a radiologist, CAD is capable of detecting different LNs and thereby has the potential to enhance a reader's detection rate. While promising characterization performances are obtained, the tool's performance in terms of texture classification remains a subject of concern.

Clinical relevance statement: Numerous lung nodule computer-aided detection-systems are commercially available, with some of them solely being externally validated based on their detection performance on solid nodules. We encourage researchers to assess performances by incorporating all relevant characteristics, including part-solid and ground-glass nodules.

Key points: Few computer-aided detection (CAD) systems are externally validated for automatic detection and characterization of lung nodules. A detection sensitivity of 81.4% and an overall texture classification sensitivity of 77.2% were measured utilizing CAD. CAD has the potential to increase single reader detection rate, however, improvement in texture classification is required.