Outcome of transarterial radioembolization in patients with hepatocellular carcinoma as a first-line interventional therapy and after a previous transarterial chemoembolization.

Purpose: Due to a lack of data, there is an ongoing debate regarding the optimal frontline interventional therapy for unresectable hepatocellular carcinoma (HCC). The aim of the study is to compare the results of transarterial radioembolization (TARE) as the first-line therapy and as a subsequent therapy following prior transarterial chemoembolization (TACE) in these patients. Methods: A total of 83 patients were evaluated, with 38 patients having undergone at least one TACE session prior to TARE [27 male; mean age 67.2 years; 68.4% stage Barcelona clinic liver cancer (BCLC) B, 31.6% BCLC C]; 45 patients underwent primary TARE (33 male; mean age 69.9 years; 40% BCLC B, 58% BCLC C). Clinical [age, gender, BCLC stage, activity in gigabecquerel (GBq), Child-Pugh status, portal vein thrombosis, tumor volume] and procedural [overall survival (OS), local tumor control (LTC), and progression-free survival (PFS)] data were compared. A regression analysis was performed to evaluate OS, LTC, and PFS. Results: No differences were found in OS (95% CI: 1.12, P = 0.289), LTC (95% CI: 0.003, P = 0.95), and PFS (95% CI: 0.4, P = 0.525). The regression analysis revealed a relationship between Child-Pugh score (P = 0.005), size of HCC lesions (>10 cm) (P = 0.022), and OS; neither prior TACE (Child-Pugh B patients; 95% CI: 0.120, P = 0.729) nor number of lesions (>10; 95% CI: 2.930, P = 0.087) correlated with OS. Conclusion: Prior TACE does not affect the outcome of TARE in unresectable HCC.

Interventional treatment of refractory non-traumatic chylous effusions in patients with lymphoproliferative disorders.

To report results of interventional treatment of refractory non-traumatic abdomino-thoracic chylous effusions in patients with lymphoproliferative disorders. 17 patients (10 male; mean age 66.7 years) with lymphoproliferative disorders suffered from non-traumatic chylous effusions (chylothorax n = 11, chylous ascites n = 3, combined abdomino-thoracic effusion n = 3) refractory to chemotherapy and conservative therapy. All underwent x-ray lymphangiography with iodized-oil to evaluate for and at the same time treat lymphatic abnormalities (leakage, chylo-lymphatic reflux with/without obstruction of central drainage). In patients with identifiable active leakage additional lymph-vessel embolization was performed. Resolution of effusions was deemed as clinical success. Lymphangiography showed reflux in 8/17 (47%), leakage in 2/17 (11.8%), combined leakage and reflux in 3/17 (17.6%), lymphatic obstruction in 2/17 (11.8%) and normal findings in 2/17 cases (11.8%). 12/17 patients (70.6%) were treated by lymphangiography alone; 5/17 (29.4%) with leakage received additional embolization (all technically successful). Effusions resolved in 15/17 cases (88.2%); 10/12 (83.3%) resolved after lymphangiography alone and in 5/5 patients (100%) after embolization. Time-to-resolution of leakage was significantly shorter after embolization (within one day in all cases) than lymphangiography (median 9 [range 4-30] days; p = 0.001). There was no recurrence of symptoms or post-interventional complications during follow-up (median 445 [40-1555] days). Interventional-radiological treatment of refractory, non-traumatic lymphoma-induced chylous effusions is safe and effective. Lymphangiography identifies lymphatic abnormalities in the majority of patients and leads to resolution of effusions in > 80% of cases. Active leakage is found in only a third of patients and can be managed by additional embolization.

MRI proton density fat fraction for estimation of tumor grade in steatotic hepatocellular carcinoma.

OBJECTIVES: Image-based detection of intralesional fat in focal liver lesions has been established in diagnostic guidelines as a feature indicative of hepatocellular carcinoma (HCC) and associated with a favorable prognosis. Given recent advances in MRI-based fat quantification techniques, we investigated a possible relationship between intralesional fat content and histologic tumor grade in steatotic HCCs. METHODS: Patients with histopathologically confirmed HCC and prior MRI with proton density fat fraction (PDFF) mapping were retrospectively identified. Intralesional fat of HCCs was assessed using an ROI-based analysis and the median fat fraction of steatotic HCCs was compared between tumor grades G1-3 with non-parametric testing. ROC analysis was performed in case of statistically significant differences (p < 0.05). Subgroup analyses were conducted for patients with/without liver steatosis and with/without liver cirrhosis. RESULTS: A total of 57 patients with steatotic HCCs (62 lesions) were eligible for analysis. The median fat fraction was significantly higher for G1 lesions (median [interquartile range], 7.9% [6.0─10.7%]) than for G2 (4.4% [3.2─6.6%]; p = .001) and G3 lesions (4.7% [2.8─7.8%]; p = .036). PDFF was a good discriminator between G1 and G2/3 lesions (AUC .81; cut-off 5.8%, sensitivity 83%, specificity 68%) with comparable results in patients with liver cirrhosis. In patients with liver steatosis, intralesional fat content was higher than in the overall sample, with PDFF performing better in distinguishing between G1 and G2/3 lesions (AUC .92; cut-off 8.8%, sensitivity 83%, specificity 91%). CONCLUSIONS: Quantification of intralesional fat using MRI PDFF mapping allows distinction between well- and less-differentiated steatotic HCCs. CLINICAL RELEVANCE: PDFF mapping may help optimize precision medicine as a tool for tumor grade assessment in steatotic HCCs. Further investigation of intratumoral fat content as a potential prognostic indicator of treatment response is encouraged. KEY POINTS: • MRI proton density fat fraction mapping enables distinction between well- (G1) and less- (G2 and G3) differentiated steatotic hepatocellular carcinomas. • In a retrospective single-center study with 62 histologically proven steatotic hepatocellular carcinomas, G1 tumors showed a higher intralesional fat content than G2 and G3 tumors (7.9% vs. 4.4% and 4.7%; p = .004). • In liver steatosis, MRI proton density fat fraction mapping was an even better discriminator between G1 and G2/G3 steatotic hepatocellular carcinomas.

Cardiac adverse reactions of COVID-19 vaccination: cardiac MRI findings.

BACKGROUND: The rapid development of COVID-19 vaccines in the wake of the COVID-19 pandemic has led to an equally expediently deployed vaccination campaign with more than 12 billion vaccinations administered worldwide. Reports of vaccine-associated adverse reactions (VAARs) have ranged from headaches and pain at the injection site to potentially life-threatening events such as cerebral venous sinus thrombosis. The heart has also not been spared of VAARs, as vaccine-associated myocardial infarction and more commonly, albeit still rare, myocarditis and perimyocarditis have been reported in predominantly young male recipients. METHODOLOGICAL INNOVATIONS: Cardiac magnetic resonance imaging findings of vaccine-associated myocarditis such as prolonged T1 and T2 relaxation times, increased T2 signal intensity ratio, and subepicardial late gadolinium enhancement have been demonstrated to be similar to those in virus-induced myocarditis, enabling the use of the modified 2018 Lake Louise Criteria for diagnostic purposes to confirm vaccination-associated myocardial inflammation. Other reported cardiac findings such as cardiomyopathies and arrhythmias were confined to case reports. The incidence of myocardial infarction was not noted to be higher than in the overall population. CONCLUSION: The overall preliminary prognosis of vaccine- associated myocarditis seems to be good as suggested by initial reports, but long-term follow-up is needed to sufficiently assess possible sequelae and consequences.

MR-lymphangiography identifies lymphatic pathologies in patients with idiopathic recurrent cervical swelling.

Background: Idiopathic recurrent cervical swelling may be caused by lymphatic abnormalities. Methods: Ten patients (9 females, mean age 51.2 ± 7) with idiopathic recurrent cervical swelling underwent MR-lymphangiography (MRL). MR-lymphangiograms were evaluated regarding lymphatic anatomy and flow. Individualized treatment was recommended according to MRL-findings. Results: 8/10 patients presented with left-sided, 2/10 with right-sided swelling. Pathological lymph-flow was identified in all cases: thoracic duct dilatation in patients with left-sided and right lymphatic duct dilatation in right-sided swelling, accessory thoracic lymphatics in 7/10 and reflux in 8/10 cases. In two cases, a lymphatic thrombus was identified.After treatment, symptoms resolved completely in 6/10 cases and partially in 1/10 cases. The remaining three patients have intermittent swellings but have no treatment wish. Conclusion: Idiopathic recurrent cervical swelling can be caused by lymphatic anomalies. MRL displays impaired lymphatic drainage, lymphatic vessel dilatation, and chylolymphatic reflux as hallmarks of this condition and may aid in targeted treatment planning.

Effect of Contrast Agent Dose Reduction on Vascular Enhancement and Image Quality in Thoracoabdominal Dynamic 3-Dimensional Magnetic Resonance Angiography: A Systematic Intraindividual Analysis in Pigs.

OBJECTIVE: High spatial and temporal resolution contrast-enhanced magnetic resonance angiography (MRA) with gadolinium-based contrast agents (GBCAs) at standard dose offers both detailed anatomic information on both arterial and venous vessels and hemodynamic characteristics. Several preclinical and clinical dynamic 3-dimensional (3D) MRA studies that focused on arterial vessels only proposed that high image quality may also be achieved with significantly reduced GBCA doses, calling into question the need to use standard doses. A systematic analysis of GBCA doses and resulting image quality for both arteries and veins has not yet been performed. The purpose of this study was therefore to systematically analyze dose-dependent vascular enhancements in dynamic 3D-MRA of the thoracoabdominal vasculature at 1.5 T in an animal model to determine the optimal contrast agent protocol for optimized vascular assessment. MATERIALS AND METHODS: The vascular enhancement in thoracoabdominal dynamic 3D-MRA (time-resolved angiography with interleaved stochastic trajectories, TWIST at 1.5 T) was interindividually and intraindividually compared in 5 anesthetized Göttingen minipigs using gadobutrol at the standard dose (0.1 mmol/kg body weight, ie, 0.1 mL/kg) and at reduced doses (0.08, 0.06, 0.04, 0.02 mmol/kg) in a randomized order. All injections were performed at 2 mL/s followed by 20 mL saline. Images were quantitatively analyzed, measuring signal intensities in 5 regions that covered the passage of the GBCA through the body at different representative stages of circulation (pulmonary, arterial, and venous system). The evaluation of GBCA dose-dependent signal intensity changes in the different vascular regions was performed by linear regression analysis.The qualitative image analysis of dynamic 3D-MRA by 3 independent radiologists included the visibility of 25 arterial and venous vessel segments at different stages of GBCA passage. Possible quality losses were statistically tested by comparing image quality ratings at the reduced dose with that of the standard dose using Friedman test followed by Dunn post hoc test for multiple comparison. Significance was stated at P < 0.05. RESULTS: Quantitative analysis revealed shorter time-to-peak intervals and bolus durations in line with decreasing GBCA dose and volume in all vessels. Although the peak signal was almost independent of the administered GBCA dose at the level of the pulmonary trunk, a linear signal decrease in the abdominal aorta ( r2 = 0.96), the renal arteries ( r2 = 0.99), the inferior vena cava ( r2 = 0.99), and the portal vein ( r2 = 0.97) was observed. Cumulative analysis of arterial segments revealed significantly lower image quality at doses below 40% of the standard dose, whereas in venous segments, significantly lower image quality was observed at doses below 60% of the standard dose. CONCLUSIONS: In dynamic 3D-MRA at 1.5 T, dose reduction leads to a signal loss that is most pronounced in the venous system and results in significantly lower image quality according to the dose and vessels of interest. Careful dose reduction is thus required according to the specific diagnostic needs. For dynamic 3D-MRA of the arterial and venous system, GBCA doses of at least 60% of the standard dose up to the full dose are preferable, whereas 40% of the standard dose seems feasible if only the arterial system is to be imaged.

Cardiac MRI in Suspected Acute Myocarditis After COVID-19 mRNA Vaccination.

PURPOSE: To evaluate cardiac MRI characteristics in patients with suspected hypersensitivity myocarditis following mRNA COVID-19 vaccination. MATERIALS AND METHODS: Patients clinically suspected of acute myocarditis after COVID-19 vaccination were retrospectively analyzed and compared against a healthy control group. Cardiac MRI protocol included parameters such as T1 and T2 relaxation times, extracellular volume (ECV), T2 signal intensity ratio, and late gadolinium enhancement (LGE). Lymph node size was assessed in the patient group on the injection side. Student t-test, analyses of variance (ANOVA) with Tukey post-hoc test, and χ2 test were used for statistical analysis. RESULTS: 20 patients with clinically suspected post-vaccine myocarditis (28 ±â€Š12 years; 12 men) and 40 controls (31 ±â€Š11 years; 25 men) were evaluated. According to the 2018 Lake Louise criteria (LLC), patients with clinically suspected myocarditis were further subdivided into an LLC-positive group (n = 9) and an LLC-negative group (n = 11). The mean time of symptom onset after vaccination was 1.1 ±â€Š1.2 days (LLC-positive) and 6.5 ±â€Š9.2 days (LLC-negative). Group differences in inflammatory variables between myocarditis patients and control subjects were more pronounced in the LLC-positive group (e. g., T1 relaxation time: 1041 ±â€Š61 ms [LLC positive] vs. 1008 ±â€Š79 ms [LLC-negative] vs. 970 ±â€Š25 ms [control]; p <.001; or T2 signal intensity ratio 2.0 ±â€Š0.3 vs. 1.6 ±â€Š0.3 [LLC-negative] and vs. 1.6 ±â€Š0.3 [control], p = .012). LLC-positive patients were significantly faster in receiving an MRI after initial symptom onset (8.8 ±â€Š6.1 days vs. 52.7 ±â€Š33.4 days; p = .001) and had higher troponin T levels (3938 ±â€Š5850 ng/l vs. 9 ±â€Š11 ng/l; p <.001). LGE lesions were predominantly located at the subepicardium of the lateral wall. Axillary lymphadenopathy was more frequent in the LLC-positive group compared to the LLC-negative group (8/9 [89 %] vs. 0/11 [0 %], p < 0.001). CONCLUSION: Vaccine-induced myocarditis should be considered in patients with acute symptom onset after mRNA vaccination, especially if elevated serum troponin T is observed. Imaging findings of vaccine-induced myocarditis are similar to virus-induced myocarditis, allowing for the use of the Lake Louise Criteria for diagnostic purposes. KEY POINTS: · Vaccine-induced hypersensitivity myocarditis can be confirmed with cardiac MRI. · Especially patients with sudden onset of symptoms and elevated serum troponin T had positive cardiac MRI findings. · Cardiac MRI characteristics of vaccine-induced myocarditis are similar to those in virus-induced myocarditis. CITATION FORMAT: · Kravchenko D, Isaak A, Mesropyan N et al. Cardiac MRI in Suspected Acute Myocarditis After COVID-19 mRNA Vaccination. Fortschr Röntgenstr 2022; 194: 1003 - 1011.

Diagnostic Accuracy of Quantitative Imaging Biomarkers in the Differentiation of Benign and Malignant Vertebral Lesions : Combination of Diffusion-Weighted and Proton Density Fat Fraction Spine MRI.

PURPOSE: To compare and combine the diagnostic performance of the apparent diffusion coefficient (ADC) derived from diffusion-weighted imaging (DWI) and proton density fat fraction (PDFF) derived from chemical-shift encoding (CSE)-based water-fat magnetic resonance imaging (MRI) for distinguishing benign and malignant vertebral bone marrow lesions (VBML). METHODS: A total of 55 consecutive patients with 53 benign (traumatic, inflammatory and primary) and 36 malignant (metastatic and hematologic) previously untreated VBMLs were prospectively enrolled in this IRB-approved study and underwent sagittal DWI (single-shot spin-echo echo-planar with multi-slice short TI inversion recovery fat suppression) and CSE-based MRI (gradient-echo 6­point modified Dixon) in addition to routine clinical spine MRI at 1.5 T or 3.0 T. Diagnostic reference standard was established according to histopathology or imaging follow-up. The ADC = ADC (0, 800) and PDFF = fat / (water + fat) were calculated voxel-wise and examined for differences between benign and malignant lesions. RESULTS: The ADC and PDFF values of malignant lesions were significantly lower compared to benign lesions (mean ADC 861â€¯× 10-6 mm2/s vs. 1323â€¯× 10-6 mm2/s, p < 0.001; mean PDFF 3.1% vs. 28.2%, p < 0.001). The areas under the curve (AUC) and diagnostic accuracies were 0.847 (p < 0.001) and 85.4% (cut-off at 1084.4â€¯× 10-6 mm2/s) for ADC and 0.940 (p < 0.001) and 89.9% for PDFF (cut-off at 7.8%), respectively. The combined use of ADC and PDFF improved the diagnostic accuracy to 96.6% (malignancy if ADC ≤ 1118.2â€¯× 10-6 mm2/s and PDFF ≤ 20.0%, otherwise benign). CONCLUSION: Quantitative evaluation of both ADC and PDFF was useful in differentiating benign VBMLs from malignancy. The combination of ADC and PDFF improved the diagnostic performance and yielded high diagnostic accuracy for the differentiation of benign and malignant VBMLs.

Proton Density Fat Fraction Spine MRI for Differentiation of Erosive Vertebral Endplate Degeneration and Infectious Spondylitis.

Vertebral Modic type 1 (MT1) degeneration may mimic infectious disease on conventional spine magnetic resonance imaging (MRI), potentially leading to additional costly and invasive investigations. This study evaluated the diagnostic performance of the proton density fat fraction (PDFF) for distinguishing MT1 degenerative endplate changes from infectious spondylitis. A total of 31 and 22 patients with equivocal diagnosis of MT1 degeneration and infectious spondylitis, respectively, were retrospectively enrolled in this IRB-approved retrospective study and examined with a chemical-shift encoding (CSE)-based water-fat 3D six-echo modified Dixon sequence in addition to routine clinical spine MRI. Diagnostic reference standard was established according to histopathology or clinical and imaging follow-up. Intravertebral PDFF [%] and PDFFratio (i.e., vertebral endplate PDFF/normal vertebrae PDFF) were calculated voxel-wise within the single most prominent edematous bone marrow lesion per patient and examined for differences between MT1 degeneration and infectious spondylitis. Mean PDFF and PDFFratio of infectious spondylitis were significantly lower compared to MT1 degenerative changes (mean PDFF, 4.28 ± 3.12% vs. 35.29 ± 17.15% [p < 0.001]; PDFFratio, 0.09 ± 0.06 vs. 0.67 ± 0.37 [p < 0.001]). The areas under the curve (AUC) and diagnostic accuracies were 0.977 (p < 0.001) and 98.1% (cut-off at 12.9%) for PDFF and 0.971 (p < 0.001) and 98.1% (cut-off at 0.27) for PDFFratio. Our data suggest that quantitative evaluation of vertebral PDFF can provide a high diagnostic accuracy for differentiating erosive MT1 endplate changes from infectious spondylitis.

Proton density fat fraction MRI of vertebral bone marrow: Accuracy, repeatability, and reproducibility among readers, field strengths, and imaging platforms.

BACKGROUND: Chemical shift-encoding based water-fat MRI is an emerging method to noninvasively assess proton density fat fraction (PDFF), a promising quantitative imaging biomarker for estimating tissue fat concentration. However, in vivo validation of PDFF is still lacking for bone marrow applications. PURPOSE: To determine the accuracy and precision of MRI-determined vertebral bone marrow PDFF among different readers and across different field strengths and imager manufacturers. STUDY TYPE: Repeatability/reproducibility. SUBJECTS: Twenty-four adult volunteers underwent lumbar spine MRI with one 1.5T and two different 3.0T MR scanners from two vendors on the same day. FIELD STRENGTH/SEQUENCE: 1.5T and 3.0T/3D spoiled-gradient echo multipoint Dixon sequences. ASSESSMENT: Two independent readers measured intravertebral PDFF for the three most central slices of the L1-5 vertebral bodies. Single-voxel MR spectroscopy (MRS)-determined PDFF served as the reference standard for PDFF estimation. STATISTICAL TESTS: Accuracy and bias were assessed by Pearson correlation, linear regression analysis, and Bland-Altman plots. Repeatability and reproducibility were evaluated by Wilcoxon signed rank test, Friedman test, and coefficients of variation. Intraclass correlation coefficients were used to validate intra- and interreader as well as intraimager agreements. RESULTS: MRI-based PDFF estimates of lumbar bone marrow were highly correlated (r2 = 0.899) and accurate (mean bias, -0.6%) against the MRS-determined PDFF reference standard. PDFF showed high linearity (r2 = 0.972-0.978) and small mean bias (0.6-1.5%) with 95% limits of agreement within ±3.4% across field strengths, imaging platforms, and readers. Repeatability and reproducibility of PDFF were high, with the mean overall coefficient of variation being 0.86% and 2.77%, respectively. The overall intraclass correlation coefficient was 0.986 as a measure for an excellent interreader agreement. DATA CONCLUSION: MRI-based quantification of vertebral bone marrow PDFF is highly accurate, repeatable, and reproducible among readers, field strengths, and MRI platforms, indicating its robustness as a quantitative imaging biomarker for multicentric studies. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1762-1772.

Quantitative evaluation of T2* relaxation times for the differentiation of acute benign and malignant vertebral body fractures.

OBJECTIVES: The aim of this prospective study was to evaluate the diagnostic performance of T2*-weighted magnetic resonance imaging (MRI) to differentiate between acute benign and neoplastic vertebral compression fractures (VCFs). MATERIALS AND METHODS: Thirty-seven consecutive patients with a total of 52 VCFs were prospectively enrolled in this IRB approved study. All VCFs were categorized as either benign or malignant according to direct bone biopsy and histopathologic confirmation. In addition to routine clinical spine MRI including at least sagittal T1-weighted, T2-weighted and T2 spectral attenuated inversion recovery (SPAIR)-weighted sequences, all patients underwent an additional sagittal six-echo modified Dixon gradient-echo sequence of the spine at 3.0-T. Intravertebral T2* and T2*ratio (fracture T2*/normal vertebrae T2*) for acute benign and malignant VCFs were calculated using region-of-interest analysis and compared between both groups. Additional receiver operating characteristic analyses were performed. Five healthy subjects were scanned three times to determine the short-term reproducibility of vertebral T2* measurements. RESULTS: There were 27 acute benign and 25 malignant VCFs. Both T2* and T2*ratio of malignant VCFs were significantly higher compared to acute benign VCFs (T2*, 30 ± 11 vs. 19 ± 11 ms [p = 0.001]; T2*ratio, 2.9 ± 1.6 vs. 1.2 ± 0.7 [p < 0.001]). The areas under the curve were 0.77 for T2* and 0.88 for T2*ratio, yielding an accuracy of 73% and 89% for distinguishing acute benign from malignant VCFs. The root mean square absolute precision error was 0.44 ms as a measure for the T2* short-term reproducibility. CONCLUSION: Quantitative assessment of vertebral bone marrow T2* relaxation times provides good diagnostic accuracy for the differentiation of acute benign and malignant VCFs.

Proton density fat fraction (PDFF) MR imaging for differentiation of acute benign and neoplastic compression fractures of the spine.

OBJECTIVES: To evaluate the diagnostic performance of proton density fat fraction (PDFF) magnetic resonance imaging (MRI) to differentiate between acute benign and neoplastic vertebral compression fractures (VCFs). METHODS: Fifty-seven consecutive patients with 46 acute benign and 41 malignant VCFs were prospectively enrolled in this institutional review board approved study and underwent routine clinical MRI with an additional six-echo modified Dixon sequence of the spine at a clinical 3.0-T scanner. All fractures were categorised as benign or malignant according to either direct bone biopsy or 6-month follow-up MRI. Intravertebral PDFF and PDFFratio (fracture PDFF/normal vertebrae PDFF) for benign and malignant VCFs were calculated using region-of-interest analysis and compared between both groups. Additional receiver operating characteristic and binary logistic regression analyses were performed. RESULTS: Both PDFF and PDFFratio of malignant VCFs were significantly lower compared to acute benign VCFs [PDFF, 3.48 ± 3.30% vs 23.99 ± 11.86% (p < 0.001); PDFFratio, 0.09 ± 0.09 vs 0.49 ± 0.24 (p < 0.001)]. The areas under the curve were 0.98 for PDFF and 0.97 for PDFFratio, yielding an accuracy of 96% and 95% for differentiating between acute benign and malignant VCFs. PDFF remained as the only imaging-based variable to independently differentiate between acute benign and malignant VCFs on multivariate analysis (odds ratio, 0.454; p = 0.005). CONCLUSIONS: Quantitative assessment of PDFF derived from modified Dixon water-fat MRI has high diagnostic accuracy for the differentiation of acute benign and malignant vertebral compression fractures. KEY POINTS: • Chemical-shift-encoding based water-fat MRI can reliably assess vertebral bone marrow PDFF • PDFF is significantly higher in acute benign than in malignant VCFs • PDFF provides high accuracy for differentiating acute benign from malignant VCFs.

Proton density fat fraction (PDFF) MRI for differentiation of benign and malignant vertebral lesions.

OBJECTIVES: To investigate whether proton density fat fraction (PDFF) measurements using a six-echo modified Dixon sequence can help to differentiate between benign and malignant vertebral bone marrow lesions. METHODS: Sixty-six patients were prospectively enrolled in our study. In addition to conventional MRI at 3.0-Tesla including at least sagittal T2-weighted/spectral attenuated inversion recovery and T1-weighted sequences, all patients underwent a sagittal six-echo modified Dixon sequence of the spine. The mean PDFF was calculated using regions of interest and compared between vertebral lesions. A cut-off value of 6.40% in PDFF was determined by receiver operating characteristic curves and used to differentiate between malignant (< 6.40%) and benign (≥ 6.40%) vertebral lesions. RESULTS: There were 77 benign and 44 malignant lesions. The PDFF of malignant lesions was statistically significant lower in comparison with benign lesions (p < 0.001) and normal vertebral bone marrow (p < 0.001). The areas under the curves (AUC) were 0.97 for differentiating benign from malignant lesions (p < 0.001) and 0.95 for differentiating acute vertebral fractures from malignant lesions (p < 0.001). This yielded a diagnostic accuracy of 96% in the differentiation of both benign lesions and acute vertebral fractures from malignancy. CONCLUSION: PDFF derived from six-echo modified Dixon allows for differentiation between benign and malignant vertebral lesions with a high diagnostic accuracy. KEY POINTS: • Establishing a diagnosis of indeterminate vertebral lesions is a common clinical problem • Benign bone marrow processes may mimic the signal alterations observed in malignancy • PDFF differentiates between benign and malignant lesions with a high diagnostic accuracy • PDFF of non-neoplastic vertebral lesions is significantly higher than that of malignancy • PDFF from six-echo modified Dixon may help avoid potentially harmful bone biopsy.

Prognostic value of pretreatment diffusion-weighted magnetic resonance imaging for outcome prediction of colorectal cancer liver metastases undergoing 90Y-microsphere radioembolization.

PURPOSE: To investigate the clinical potential of pretreatment apparent diffusion coefficient (ADC) on diffusion-weighted magnetic resonance imaging (DWI) for therapy response and outcome prediction in patients with liver-predominant metastatic colorectal cancer (CRC) undergoing radioembolization with 90Yttrium-microspheres (90Y-RE). METHODS: Forty-six consecutive patients with unresectable CRC liver metastases underwent standardized clinical DWI on a 1.5 T MR scanner prior to and 4-6 weeks after 90Y-RE. Pretreatment clinical parameters, ADC values derived from region-of-interest analysis, and the corresponding tumor sizes of three treated liver metastases per subject were recorded. Long-term tumor response to radioembolization was categorized into response (partial remission) and nonresponse (stable disease, progressive disease) according to Response Evaluation Criteria in Solid Tumors v1.1 (RECIST) 3 months after treatment. Associations between long-term tumor response and the clinical and imaging parameters were evaluated. The impact of pretreatment clinical and imaging parameters on progression-free survival (PFS) and overall survival (OS) was further assessed by Kaplan-Meier and multivariate Cox-regression analyses. RESULTS: Nonresponders had higher hepatic tumor burden (p = 0.021) and lower ADC values than patients responding to 90Y-RE, both pretreatment (986 ± 215 vs. 1162 ± 178; p = 0.036) and posttreatment (1180 ± 350 vs. 1598 ± 225; p = 0.002). ADC values higher than 935 × 10-6 mm2 (5 vs. 3 months; p = 0.022) and hepatic tumor burden ≤25% (6 vs. 3 months; p = 0.014) were associated with longer median PFS, whereas ADC >935 × 10-6 mm2 (14 vs. 6 months; p = 0.02), hepatic tumor burden ≤25% (14 vs. 6 months; p = 0.048), size of the largest metastasis <4.7 cm (18 vs. 7 months; p = 0.024), and Eastern Cooperative Oncology Group (ECOG) score <1 (8 vs. 5 months; p = 0.045) were associated with longer median OS. On multivariate analysis, ADC >935 × 10-6 mm2 and hepatic tumor burden ≤25% remained prognostic factors for PFS, and ADC >935 × 10-6 mm2 and size of the largest metastasis <4.7 cm were independent predictors of OS. CONCLUSION: Pretreatment ADC on DWI represents a valuable prognostic biomarker for predicting both the therapeutic efficacy and survival prognosis in CRC liver metastases treated by 90Y-RE, allowing risk stratification and potentially optimizing further treatment strategies.

Diffusion-weighted magnetic resonance imaging predicts survival in patients with liver-predominant metastatic colorectal cancer shortly after selective internal radiation therapy.

OBJECTIVES: To investigate whether quantifications of apparent diffusion coefficient (ADC) on diffusion-weighted imaging (DWI) can predict overall survival (OS) in patients with liver-predominant metastatic colorectal cancer (CRC) following selective internal radiation therapy with 90Yttrium-microspheres (SIRT). METHODS: Forty-four patients underwent DWI 19 ± 16 days before and 36 ± 10 days after SIRT. Tumour-size and intratumoral minimal ADC (minADC) values were measured for 132 liver metastases on baseline and follow-up DWI. Optimal functional imaging response to treatment was determined by receiver operating characteristics and defined as ≥22 % increase in post-therapeutic minADC. Survival analysis was performed with the Kaplan-Meier method and Cox-regression comparing various variables with potential impact on OS. RESULTS: Median OS was 8 months. The following parameters were significantly associated with median OS: optimal functional imaging response (18 vs. 5 months; p < 0.001), hepatic tumour burden <50 % (8 vs. 5 months; p = 0.018), Eastern Cooperative Oncology Group performance scale <1 (10 vs. 4 months; p = 0.012) and progressive disease according to Response and Evaluation Criteria in Solid Tumours (8 vs. 3 months; p = 0.001). On multivariate analysis, optimal functional imaging response and hepatic tumour burden remained independent predictors of OS. CONCLUSION: Functional imaging response assessment using minADC changes on DWI may predict survival in CRC shortly after SIRT. KEY POINTS: • Relative minADC changes may predict survival in liver-predominant metastatic colorectal cancer following SIRT • Intratumoral minADC changes by ≥22 % were best to predict an improved overall survival • Functional imaging response assessment is feasible before anatomic tumour-size changes occur • minADC changes might guide future therapy management in sequential lobar radioembolization approaches.