Free-breathing accelerated whole-body MRI using an automated workflow: Comparison with conventional breath-hold sequences.

Whole-body magnetic resonance imaging (MRI) has become increasingly popular in oncology. However, the long acquisition time might hamper its widespread application. We sought to assess and compare free-breathing sequences with conventional breath-hold examinations in whole-body MRI using an automated workflow process. This prospective study consisted of 20 volunteers and six patients with a variety of pathologies who had undergone whole-body 1.5-T MRI that included T1-weighted radial and Dixon volumetric interpolated breath-hold examination sequences. Free-breathing sequences were operated by using an automated user interface. Image quality, diagnostic confidence, and image noise were evaluated by two experienced radiologists. Additionally, signal-to-noise ratio was measured. Diagnostic performance for the overall detection of pathologies was assessed using the area under the receiver operating characteristics curve (AUC). Study participants were asked to rate their examination experiences in a satisfaction survey. MR free-breathing scans were rated as at least equivalent to conventional MR scans in more than 92% of cases, showing high overall diagnostic accuracy (95% [95% CI 92-100]) and performance (AUC 0.971, 95% CI 0.942-0.988; p < 0.0001) for the assessment of pathologies at simultaneously reduced examination times (25 ± 2 vs. 32 ± 3 min; p < 0.0001). Interrater agreement was excellent for both free-breathing (Ï° = 0.96 [95% CI 0.88-1.00]) and conventional scans (Ï° = 0.93 [95% CI 0.84-1.00]). Qualitative and quantitative assessment for image quality, image noise, and diagnostic confidence did not differ between the two types of MR image acquisition (all p > 0.05). Scores for patient satisfaction were significantly better for free-breathing compared with breath-hold examinations (p = 0.0145), including significant correlations for the grade of noise (r = 0.79, p < 0.0001), tightness (r = 0.71, p < 0.0001), and physical fatigue (r = 0.52, p = 0.0065). In summary, free-breathing whole-body MRI in tandem with an automated user interface yielded similar diagnostic performance at equivalent image quality and shorter acquisition times compared to conventional breath-hold sequences.

Advanced biomedical imaging for accurate discrimination and prognostication of mediastinal masses.

BACKGROUND: To investigate the potential of radiomic features and dual-source dual-energy CT (DECT) parameters in differentiating between benign and malignant mediastinal masses and predicting patient outcomes. METHODS: In this retrospective study, we analysed data from 90 patients (38 females, mean age 51 ± 25 years) with confirmed mediastinal masses who underwent contrast-enhanced DECT. Attenuation, radiomic features and DECT-derived imaging parameters were evaluated by two experienced readers. We performed analysis of variance (ANOVA) and Chi-square statistic tests for data comparison. Receiver operating characteristic curve analysis and Cox regression tests were used to differentiate between mediastinal masses. RESULTS: Of the 90 mediastinal masses, 49 (54%) were benign, including cases of thymic hyperplasia/thymic rebound (n = 10), mediastinitis (n = 16) and thymoma (n = 23). The remaining 41 (46%) lesions were classified as malignant, consisting of lymphoma (n = 28), mediastinal tumour (n = 4) and thymic carcinoma (n = 9). Significant differences were observed between benign and malignant mediastinal masses in all DECT-derived parameters (p ≤ .001) and 38 radiomic features (p ≤ .044) obtained from contrast-enhanced DECT. The combination of these methods achieved an area under the curve of .98 (95% CI, .893-1.000; p < .001) to differentiate between benign and malignant masses, with 100% sensitivity and 91% specificity. Throughout a follow-up of 1800 days, a multiparametric model incorporating radiomic features, DECT parameters and gender showed promising prognostic power in predicting all-cause mortality (c-index = .8 [95% CI, .702-.890], p < .001). CONCLUSIONS: A multiparametric approach combining radiomic features and DECT-derived imaging biomarkers allows for accurate and noninvasive differentiation between benign and malignant masses in the anterior mediastinum.

Unveiling the diagnostic enigma of D-dimer testing in cancer patients: Current evidence and areas of application.

BACKGROUND: Cancer is a well-known risk factor for venous thromboembolism (VTE). A combined strategy of D-dimer testing and clinical pre-test probability is usually used to exclude VTE. However, its effectiveness is diminished in cancer patients due to reduced specificity, ultimately leading to a decreased clinical utility. This review article seeks to provide a comprehensive summary of how to interpret D-dimer testing in cancer patients. METHODS: In accordance with PRISMA standards, literature pertaining to the diagnostic and prognostic significance of D-dimer testing in cancer patients was carefully chosen from reputable sources such as PubMed and the Cochrane databases. RESULTS: D-dimers have not only a diagnostic value in ruling out VTE but can also serve as an aid for rule-in if their values exceed 10-times the upper limit of normal. This threshold allows a diagnosis of VTE in cancer patients with a positive predictive value of more than 80%. Moreover, elevated D-dimers carry important prognostic information and are associated with VTE reoccurrence. A gradual increase in risk for all-cause death suggests that VTE is also an indicator of biologically more aggressive cancer types and advanced cancer stages. Considering the lack of standardization for D-dimer assays, it is essential for clinicians to carefully consider the variations in assay performance and the specific test characteristics of their institution. CONCLUSIONS: Standardizing D-dimer assays and developing modified pretest probability models specifically for cancer patients, along with adjusted cut-off values for D-dimer testing, could significantly enhance the accuracy and effectiveness of VTE diagnosis in this population.

Diagnostic accuracy of color-coded virtual noncalcium reconstructions derived from portal venous phase dual-energy CT in the assessment of lumbar disk herniation.

OBJECTIVES: To investigate the diagnostic accuracy of color-coded contrast-enhanced dual-energy CT virtual noncalcium (VNCa) reconstructions for the assessment of lumbar disk herniation compared to unenhanced VNCa imaging. METHODS: A total of 91 patients were retrospectively evaluated (65 years ± 16; 43 women) who had undergone third-generation dual-source dual-energy CT and 3.0-T MRI within an examination interval up to 3 weeks between November 2019 and December 2020. Eight weeks after assessing unenhanced color-coded VNCa reconstructions for the presence and degree of lumbar disk herniation, corresponding contrast-enhanced portal venous phase color-coded VNCa reconstructions were independently analyzed by the same five radiologists. MRI series were additionally analyzed by one highly experienced musculoskeletal radiologist and served as reference standard. RESULTS: MRI depicted 210 herniated lumbar disks in 91 patients. VNCa reconstructions derived from contrast-enhanced CT scans showed similar high overall sensitivity (93% vs 95%), specificity (94% vs 95%), and accuracy (94% vs 95%) for the assessment of lumbar disk herniation compared to unenhanced VNCa images (all p > .05). Interrater agreement in VNCa imaging was excellent for both, unenhanced and contrast-enhanced CT (κ = 0.84 vs κ = 0.86; p > .05). Moreover, ratings for diagnostic confidence, image quality, and noise differed not significantly between unenhanced and contrast-enhanced VNCa series (all p > .05). CONCLUSIONS: Color-coded VNCa reconstructions derived from contrast-enhanced dual-energy CT yield similar diagnostic accuracy for the depiction of lumbar disk herniation compared to unenhanced VNCa imaging and therefore may improve opportunistic retrospective lumbar disk herniation assessment, particularly in case of staging CT examinations. KEY POINTS: • Color-coded dual-source dual-energy CT virtual noncalcium (VNCa) reconstructions derived from portal venous phase yield similar high diagnostic accuracy for the assessment of lumbar disk herniation compared to unenhanced VNCa CT series (94% vs 95%) with MRI serving as a standard of reference. • Diagnostic confidence, image quality, and noise levels differ not significantly between unenhanced and contrast-enhanced portal venous phase VNCa dual-energy CT series. • Dual-source dual-energy CT might have the potential to improve opportunistic retrospective lumbar disk herniation assessment in CT examinations performed for other indications through reconstruction of VNCa images.

[Small hepatocellular carcinoma : Diagnostics according to guidelines and established in the clinical setting]. / Das kleine hepatozelluläre Karzinom : Leitliniengerechte und klinisch etablierte Diagnostik.

CLINICAL/METHODICAL ISSUE: The diagnosis of hepatocellular carcinoma (HCC)-especially the characterization of small lesions <2 cm-continues to be a radiological challenge. STANDARD RADIOLOGICAL METHODS: In the current S3 guideline on diagnosis and therapy of HCC, contrast-enhanced imaging examinations, such as contrast-enhanced ultrasonography (CEUS), computed tomography (CT), and magnetic resonance imaging (MRI), are still the diagnostic standard. METHODOLOGICAL INNOVATIONS: HCC in the cirrhotic liver should be diagnosed by its typical contrast-enhanced pattern in the MRI. In addition, the use of quality assurance instruments such as LI-RADS (Liver Imaging Reporting and Data System) contributes to the desired consistency of findings, even with small ambiguous findings. PERFORMANCE: Many studies have shown that the LI-RADS classification reflects the likelihood of HCC and other malignant liver lesions. ACHIEVEMENTS: Guidelines and quality assurance instruments contribute to a more precise diagnosis in patients with suspected HCC. PRACTICAL RECOMMENDATIONS: A guideline-compliant diagnostic algorithm and the LI-RADS should be used across the board for accurate HCC diagnostics.

Transarterial chemoembolization of colorectal cancer liver metastasis: improved tumor response by DSM-TACE versus conventional TACE, a prospective, randomized, single-center trial.

OBJECTIVES: To prospectively evaluate the therapy response of third-line TACE with DSM or lipiodol in the treatment of CRLM using MRI. METHODS: In this prospective, randomized, single-center trial, patients were randomly assigned to receive TACE therapy with either lipiodol or DSM as the embolization agent. Therapy response was evaluated using MRI. Local tumor response was determined according to RECIST 1.1, and survival data was analyzed using the Kaplan-Meier estimator. RESULTS: Fifty patients (35 male, 15 female) were randomized and included in the survival analysis, whereas 31 patients completed therapy and were considered for evaluation of tumor responses (cTACE: n = 13, DSM-TACE: n = 18). In the cTACE group, PR was observed in 23%, SD in 15%, and PD in 62%. In the DSM-TACE-group, PR was observed in 22% of patients, SD in 56%, and PD in 22% (p = 0.047). In addition, the DSM-TACE group showed statistically significant tumor volume reduction (p = 0.006). Median apparent diffusion coefficient values were not significantly different between both groups at baseline (p = 0.26) and study endpoint (p = 0.83). Median survival in the cTACE group was 13 months (95% confidence interval, range 5-40 months) compared to 16 months (95% confidence interval, range 1-48 months) in the DSM-TACE group, exhibiting no statistically significant difference (p = 0.75). CONCLUSION: DSM-TACE showed a significant difference reducing tumor volume and in tumor response according to RECIST 1.1 compared to cTACE. Thus, patients with CRLM might not only benefit from short embolization effect of DSM-TACE but also from better tumor responses. Apparent diffusion coefficients were not significantly different between both groups and cannot be used as a biomarker for monitoring for therapeutic effect of TACE. KEY POINTS: • To our knowledge, this is the first prospective study that directly compared cTACE and DSM-TACE in patients with CRLM. • DSM-TACE showed a significant difference reducing tumor volume (p = 0.006) and in tumor response according to RECIST 1.1 (p = 0.047) compared to cTACE. • Survival analysis showed a median survival of 13 months in the cTACE group compared to 16 months in the DSM-TACE group (p = 0.75).

Comparison of machine learning algorithms to predict clinically significant prostate cancer of the peripheral zone with multiparametric MRI using clinical assessment categories and radiomic features.

OBJECTIVES: To analyze the performance of radiological assessment categories and quantitative computational analysis of apparent diffusion coefficient (ADC) maps using variant machine learning algorithms to differentiate clinically significant versus insignificant prostate cancer (PCa). METHODS: Retrospectively, 73 patients were included in the study. The patients (mean age, 66.3 ± 7.6 years) were examined with multiparametric MRI (mpMRI) prior to radical prostatectomy (n = 33) or targeted biopsy (n = 40). The index lesion was annotated in MRI ADC and the equivalent histologic slides according to the highest Gleason Grade Group (GrG). Volumes of interest (VOIs) were determined for each lesion and normal-appearing peripheral zone. VOIs were processed by radiomic analysis. For the classification of lesions according to their clinical significance (GrG ≥ 3), principal component (PC) analysis, univariate analysis (UA) with consecutive support vector machines, neural networks, and random forest analysis were performed. RESULTS: PC analysis discriminated between benign and malignant prostate tissue. PC evaluation yielded no stratification of PCa lesions according to their clinical significance, but UA revealed differences in clinical assessment categories and radiomic features. We trained three classification models with fifteen feature subsets. We identified a subset of shape features which improved the diagnostic accuracy of the clinical assessment categories (maximum increase in diagnostic accuracy ΔAUC = + 0.05, p < 0.001) while also identifying combinations of features and models which reduced overall accuracy. CONCLUSIONS: The impact of radiomic features to differentiate PCa lesions according to their clinical significance remains controversial. It depends on feature selection and the employed machine learning algorithms. It can result in improvement or reduction of diagnostic performance. KEY POINTS: • Quantitative imaging features differ between normal and malignant tissue of the peripheral zone in prostate cancer. • Radiomic feature analysis of clinical routine multiparametric MRI has the potential to improve the stratification of clinically significant versus insignificant prostate cancer lesions in the peripheral zone. • Certain combinations of standard multiparametric MRI reporting and assessment categories with feature subsets and machine learning algorithms reduced the diagnostic performance over standard clinical assessment categories alone.

Diffusion-Weighted MR Imaging of Primary and Secondary Lung Cancer: Predictive Value for Response to Transpulmonary Chemoembolization and Transarterial Chemoperfusion.

PURPOSE: To examine predictive value of apparent diffusion coefficient (ADC) in diffusion-weighted imaging (DWI) for response of patients with primary and secondary lung neoplasms undergoing transpulmonary chemoembolization (TPCE) and transarterial chemoperfusion (TACP) treatment. MATERIALS AND METHODS: Thirty-one patients (mean age ± SD 64 ± 12.4 y) with 42 lung target lesions (13 primary and 29 secondary) underwent DWI and subsequent ADC analysis on a 1.5T MR imaging scanner before and 30.3 days ± 6.4 after first session of TPCE or TACP. After 3.1 treatment sessions ± 1.4 performed in 2- to 4-week intervals, morphologic response was analyzed by comparing tumor diameter and volume before and after treatment on unenhanced T1-weighted MR images. On a per-lesion basis, response was classified according to Response Evaluation Criteria In Solid Tumors. RESULTS: Threshold ADC increase of 20.7% indicated volume response with 88% sensitivity and 78% specificity (area under the curve [AUC] = 0.84). Differences between ADC changes in volume response groups were significant (P = .002). AUC for volume response predicted by ADC before treatment was 0.77. Median ADC before treatment and mean ADC change were 1.09 × 10-3 mm2/second and 0.36 × 10-3 mm2/second ± 0.23, 1.45 × 10-3 mm2/second and 0.14 × 10-3 mm2/second ± 0.16, and 1.30 × 10-3 mm2/second and 0.06 × 10-3 mm2/second ± 0.19 in partial response, stable disease, and progressive disease groups. In primary lung cancer lesions, strong negative correlation of ADC change with change in diameter (ρ = -.87, P < .001) and volume (ρ = -.66, P = .016) was found. In metastases, respective correlation coefficients were ρ = -.18 (P = .356) and ρ = -.35 (P = .061). CONCLUSIONS: ADC quantification shows considerable diagnostic value for predicting response and monitoring TPCE and TACP treatment of patients with primary and secondary lung neoplasms.

Analysis of Lipiodol uptake in angiography and computed tomography for the diagnosis of malignant versus benign hepatocellular nodules in cirrhotic liver.

OBJECTIVES: To evaluate the diagnostic value of Lipiodol distribution in angiography and CT to differentiate between hepatocellular carcinoma (HCC) and benign nodules of LI-RADS 3 and 4 lesions observed in MRI of liver cirrhosis. METHODS: This retrospective study included all patients with liver cirrhosis who had diagnosis of LI-RADS 3 or 4 lesions by MRI who underwent a Lipiodol-based angiography and post-interventional unenhanced CT- and liver biopsy. Two independent radiologists evaluated appearance, contrast enhancement, Lipiodol uptake in angiography, and morphological parameters (size, form, and density) of the lesions in unenhanced post-angiography CT. α-Fetoprotein (AFP) levels and pre-existing liver conditions were additionally taken into consideration. Differences between HCC lesions and benign nodules were analyzed. Sensitivity and specificity were calculated. P < 0.05 was considered as statistically significant. RESULTS: Of 60 patients (men, n = 42 [70.0%]; women, 18 [30.0%]; mean age, 61 ± 9.1 years) 36 (60.0%) had HCC and 24 (40.0%) benign nodules. Clear visibility in angiography (sensitivity [se], 100%; specificity [sp], 87.5%) with homogeneous or lacunar Lipiodol enhancement (se, 86.1%; sp, 100%) in consecutive CT can be diagnosed as HCC lesions in cirrhotic liver. Lesion form (p < 0.001), round or oval, and intense contrast (p < 0.001) are minor features which can facilitate the findings. Furthermore, patients with HCC showed a larger lesion size in CT (p = 0.026). CONCLUSION: Clearly detectable lesions in Lipiodol-based angiography and a homogeneous or lacunar enhancement in post-angiographic non-contrast CT allow for differentiation of intrahepatic lesions classified as LI-RADS 3 or 4 into benign vs. malign liver lesions with high sensitivity and specificity in patients with liver cirrhosis. Definite diagnosis may not require an additional biopsy. KEY POINTS: • Combination of clear visibility in Lipiodol-based angiography and homogeneous or lacunar enhancement in following native CT scan is HCC-defining. • In lesions classified with MRI as LI-RADS 3 or 4, evaluation based on Lipiodol angiography and following plain CT performed is highly sensitive and specific for the differentiation between HCC and benign nodules in a cirrhotic liver. • The results lead to an alternative pathway in the diagnosis of HCC in cirrhotic liver without the need of an additional liver biopsy.

Comparison of Radiation Dose and Image Quality of Contrast-Enhanced Dual-Source CT of the Chest: Single-Versus Dual-Energy and Second-Versus Third-Generation Technology.

OBJECTIVE: The purpose of this study was to compare radiation dose and image quality of single- and dual-energy CT (SECT, DECT) examinations of the chest in matched cohorts for second and third-generation dual-source CT (DSCT) systems. MATERIALS AND METHODS: We analyzed 200 patients (100 men; mean age, 61.7 ± 14.8 years old; 100 women, mean age, 59.4 ± 15.1 years old), matched by sex and body mass index, who had undergone clinically indicated contrast-enhanced chest CT. Four study groups, each consisting of 50 patients, were evaluated. Contrast-enhanced chest CT was performed using vendor-preset second-generation DSCT (group A, 120-kV SECT; group C, 80/Sn140-kV DECT) or third-generation DSCT (group B, 90-kV SECT; group D, 90/Sn150-kV DECT) protocols. Radiation dose assessment was normalized to a scan range of 27.5 cm. Image quality was objectively analyzed using dose-independent figure-of-merit (FOM) contrast-to-noise ratio (CNR) calculations and subjectively evaluated by three independent radiologists. RESULTS: Direct comparison of effective radiation dose for second-generation DSCT groups A and C showed statistically significant lower radiation dose values for DECT compared with SECT acquisition (3.2 ± 1.2 mSv vs 2.3 ± 0.6 mSv, p ≤ 0.004), but differences between third-generation SECT and DECT were not significant (1.2 ± 0.9 mSv vs 1.3 ± 0.6 mSv, p = 0.412). FOM CNR analysis revealed highest values for third-generation DECT (p ≤ 0.043). Differences in subjective image quality between the four groups were not statistically significant (p ≥ 0.179). CONCLUSION: Contrast-enhanced DECT examinations of the chest can be performed routinely with second- and third-generation DSCT systems without either increased radiation exposure or decreased image quality compared with SECT acquisition.

Serum ferritin is not a reliable predictor to determine iron overload in thalassemia major patients post-hematopoietic stem cell transplantation.

OBJECTIVE: Iron overload (IO) in transfusion-dependent anemia persists after hematopoietic stem cell transplantation (HSCT) and can cause long-term organ damage. In many studies, the diagnosis of IO before and after HSCT is based on serum ferritin (SF) levels rather than on assessment of liver iron concentration (LIC) by MRI or SQUID. METHOD: In a retrospective multicenter study, we analyzed the concordance for indication of iron depletion therapy and correlation between LIC and SF of 36 thalassemia patients after HSCT. LIC was determined either by MRI-R2 (FerriScan®) or SQUID. RESULTS: The concordance between LIC and SF varies over time after transplant (P = 0.011). The correlation between SF and LIC was strong in the first year (Spearman's rho 0.75; P < 0.001). In agreement, the concordance between SF and LIC concerning indication for treatment was close to 1 with an overall error rate ca. of 10%. In particular in the first year after HSCT, SF underestimates the degree of iron overload. However, in the longitudinal analysis since the second year post-HSCT onward no association was found between LIC and SF (P = 0.217). Furthermore, in the second year after HSCT, the overall error rate was 35%, whereas in the 3rd, 4th, and >4th year, it was 58%, 60%, and 25%, respectively. CONCLUSIONS: Our data suggest serum ferritin is not a reliable predictor to determine iron overload in thalassemia patients after HSCT.

How to Prevent Renal Cachexia? A Clinical Randomized Pilot Study Testing Oral Supplemental Nutrition in Hemodialysis Patients With and Without Human Immunodeficiency Virus Infection.

OBJECTIVE: End-stage renal disease associates with catabolism and sarcopenia. Hypothetically, peroral supplemental nutrition over 6 months prevents catabolism in hemodialysis patients. DESIGN: Prospective randomized pilot study (ClinicalTrials.gov Identifier: NCT00687050). SUBJECTS: Twenty-three hemodialysis patients (15 males and 7 females) with or without human immunodeficiency virus (HIV) infection of 2 ambulatory hemodialysis centers. INTERVENTION: HIV-positive hemodialysis patients (n = 7, Group 1) were started on supplemental nutrition drinks (250 kcal/day), HIV-negative hemodialysis patients (n = 16, Group 2) were randomized to supplemental nutrition drinks (250 kcal/day) or received none. MAIN OUTCOME MEASURES: Body impedance analysis, anthropometric measures, magnetic resonance imaging results for mid-iliopsoas muscle cross-sectional area and laboratory parameters including albumin, cytokines at baseline, and at 6 months follow-up. RESULTS: Seven patients in Group 1 (mean age: 50.6 ± 9.6 years) and 16 patients in Group 2 (mean age: 54.0 ± 13.3 years) were recruited. Serum creatinine (Group 1: 6.4 ± 3.0 mg/dL; Group 2: 10.7 ± 2.5 mg/dL; P < .01), Body impedance analysis-derived phase angle alpha (Group 1: 5.1 ± 1.2; Group 2: 6.9 ± 1.6; P < .01), mid-arm circumference (Group 1: 26.1 ± 1.3 cm; Group 2: 29.6 ± 2.4 cm; P < .01) were less in Group 1 versus Group 2 patients at baseline suggesting that HIV-positive hemodialysis patients had a poorer nutritional status at baseline. At 6-month follow-up, mortality was higher in Group 1 patients (29%) than in Group 2 patients (6%). There was no significant treatment effect on nutritional status in survivors of Group 1 or in the supplemental nutrition arm of Group 2 when compared with baseline or to untreated controls. CONCLUSIONS: A new oral supplemental nutrition over 6 months had no treatment effect in surviving HIV-positive hemodialysis patients or in maintenance hemodialysis patients without HIV infection. The limitations of this study were small study size and unexpected high mortality among HIV-positive hemodialysis patients.

Quiet MR sequences in clinical routine: initial experience in abdominal imaging.

OBJECTIVE: Purpose of our study was to demonstrate the feasibility and limitations of acoustic noise reduction in a standard clinical MRI protocol for abdominal imaging. METHODS: Acoustic noise and image quality were assessed in 17 patients for a standard liver imaging protocol including TSE and GRE sequences and compared to quiet optimizations as described by Heismann et al. Two blinded readers scored artifacts, the delineation of the abdominal organs and level of diagnostic confidence. Means of the sound level measurements, the ratings and the measurement of SNR and CNR were compared. RESULTS: Significant reduction of acoustic noise was measured for T2 TSE (-30.7%), T2 HASTE (-22.6%) and less difference for T1 DIXON (-4.7%) and T1 FLASH (-2.7%). SNR and CNR were lower for quiet T2 TSE (-18.0%, -23.1%) and T2 HASTE (-46.2%, -37.7%) and higher for T1 DIXON (+32.0%, +24.4%). Inter-rater correlation was k = 0.987 with p < 0.001. CONCLUSIONS: Although sequence-based noise optimizations faces problems in T1 FLASH and DIXON sequences, there is an important acoustic benefit in T2 TSE and T2 HASTE sequences, which goes along with a maintained image quality and diagnostic confidence.

Transarterial chemoembolization of hepatocellular carcinoma in a rat model: the effect of additional injection of survivin siRNA to the treatment protocol.

BACKGROUND: Transarterial chemoembolization is one of the most widely accepted interventional treatment options for treatment of hepatocellular carcinoma. Still there is a lack of a standard protocol regarding the injected chemotherapeutics. Survivin is an inhibitor of Apoptosis protein that functions to inhibit apoptosis, promote proliferation, and enhance invasion. Survivin is selectively up-regulated in many human tumors. Small interfering RNA (siRNA) can trigger an RNA interference response in mammalian cells and induce strong inhibition of specific gene expression including Survivin. The aim of the study is to assess the effectiveness of the additional injection of Survivin siRNA to the routine protocol of Transarterial Chemoembolization (TACE) for the treatment of hepatocellular carcinoma in a rat model. METHODS: The study was performed on 20 male ACI rats. On day 0 a solid Morris Hepatoma 3924A was subcapsullary implanted in the liver. On day 12 MRI measurement of the initial tumor volume (V1) was performed. TACE was performed on day 13. The rats were divided into 2 groups; Group (A, n = 10) in which 0.1 mg mitomycin, 0.1 ml lipiodol and 5.0 mg degradable starch microspheres were injected in addition 2.5 nmol survivin siRNA were injected. The same agents were injected in Group (B,=10) without Survivin siRNA. MRI was repeated on day 25 to assess the tumor volume (V2). The tumor growth ratio (V2/V1) was calculated. Western blot and immunohistochemical analysis were performed. RESULTS: For group A the mean tumor growth ratio (V2/V1) was 1.1313 +/- 0.1381, and was 3.1911 +/- 0.1393 in group B. A statistically significant difference between both groups was observed regarding the inhibition of tumor growth (P < 0.0001) where Group A showed more inhibition compared to Group B. Similarly immunohistochemical analysis showed significantly lower (p < 0.002) VEGF staining in group A compared to group B. Western Blot analysis showed a similar difference in VEGF expression (P < 0.0001). CONCLUSION: The additional injection of Survivin siRNA to the routine TACE protocol increased the inhibition of the hepatocellular carcinoma growth in a rat animal model compared to regular TACE protocol.

Intraprocedural blood volume measurement using C-arm CT as a predictor for treatment response of malignant liver tumours undergoing repetitive transarterial chemoembolization (TACE).

PURPOSE: To evaluate feasibility of measuring parenchymal blood volume (PBV) of malignant hepatic tumours using C-arm CT, test the changes in PBV following repeated transarterial chemoembolization (TACE) and correlate these changes with the change in tumour size in MRI. METHODS: 111 patients with liver malignancy were included. Patients underwent MRI and TACE in a 4- to 6-week interval. During intervention C-arm CT was performed. Images were post-processed to generate PBV maps. Blood volume data in C-arm CT and change in size in MRI were evaluated. The correlation between PBV and size was tested using Spearman rank test. RESULTS: Pre-interventional PBV maps showed a mean blood volume of 84.5 ml/1000 ml ± 62.0, follow-up PBV maps after multiple TACE demonstrated 61.1 ml/1000 ml ± 57.5. The change in PBV was statistically significant (p = 0.02). Patients with initial tumour blood volume >100 ml/1000 ml dropped 7.1% in size and 47.2% in blood volume; 50-100 ml/1000 ml dropped 4.6% in size and 25.7% in blood volume; and <50 ml/1000 ml decreased 2.8% in size and increased 82.2% in blood volume. CONCLUSION: PBV measurement of malignant liver tumours using C-arm CT is feasible. Following TACE PBV decreased significantly. Patients with low initial PBV show low local response rates and further increase in blood volume, whereas high initial tumour PBV showed better response to TACE. KEY POINTS: Parenchymal blood volume assessment of malignant hepatic lesions using C-arm CT is feasible. The parenchymal blood volume is reduced significantly following transarterial chemoembolization. Parenchymal blood volume can monitor the response of tumours after transarterial chemoembolization. Although not significant, high initial parenchymal blood volume yields better response to TACE.

Multidisciplinary sliding-gantry CT: from concept to reality.

Sliding-gantry computed tomography offers an interesting variety of treatment options for emergency radiology and clinical routine. The Frankfurt 2-room installation provides an interdisciplinary, multifunctional, and cost-effective concept. It is based on a magnetically sealed rail system for the permanent movement of the gantry between 2 adjacent rooms with fixed-mounted tables. In case of emergency or intensive care patients, routine scanning can be performed in room 1 until computed tomography diagnosis is required in room 2 and can then be continued in room 1 again. Moreover, this concept allows the simultaneous handling of 2 emergency patients.

Single-portal-phase low-tube-voltage dual-energy CT for short-term follow-up of acute pancreatitis: evaluation of CT severity index, interobserver agreement and radiation dose.

OBJECTIVES: To intra-individually compare single-portal-phase low-tube-voltage (100-kVp) computed tomography (CT) with 120-kVp images for short-term follow-up assessment of CT severity index (CTSI) of acute pancreatitis, interobserver agreement and radiation dose. METHODS: We retrospectively analysed 66 patients with acute pancreatitis who underwent initial dual-contrast-phase CT (unenhanced, arterial, portal phase) at admission and short-term (mean interval 11.4 days) follow-up dual-contrast-phase dual-energy CT. The 100-kVp and linearly blended images representing 120-kVp acquisition follow-up CT images were independently evaluated by three radiologists using a modified CTSI assessing pancreatic inflammation, necrosis and extrapancreatic complications. Scores were compared with paired t test and interobserver agreement was evaluated using intraclass correlation coefficients (ICC). RESULTS: Mean CTSI scores on unenhanced, portal- and dual-contrast-phase images were 4.9, 6.1 and 6.2 (120 kVp) and 5.0, 6.0 and 6.1 (100 kVp), respectively. Contrast-enhanced series showed a higher CTSI compared to unenhanced images (P < 0.05) but no significant differences between single- and dual-contrast-phase series (P > 0.7). CTSI scores were comparable for 100-kVp and 120-kVp images (P > 0.05). Interobserver agreement was substantial for all evaluated series and subcategories (ICC 0.67-0.93). DLP of single-portal-phase 100-kVp images was reduced by 41 % compared to 120-kVp images (363.8 versus 615.9 mGy cm). CONCLUSIONS: Low-tube-voltage single-phase 100-kVp CT provides sufficient information for follow-up evaluation of acute pancreatitis and significantly reduces radiation exposure. KEY POINTS: • Single-portal-phase CT provides sufficient evaluation for follow-up of acute pancreatitis. • Follow-up CT does not benefit from unenhanced or arterial-phase acquisition. • CT severity index scores are equal for dual-contrast-phase 100-/120-kVp acquisition (P > 0.05). • 100-kVp single-portal-phase follow-up CT of acute pancreatitis significantly reduces radiation exposure.

Temperature imaging of laser-induced thermotherapy (LITT) by MRI: evaluation of different sequences in phantom.

The purpose of this study was to evaluate magnetic resonance (MR) temperature imaging of the laser-induced thermotherapy (LITT) comparing the proton resonance frequency (PRF) and T 1 thermometry methods. LITT was applied to a liver-mimicking acrylamide gel phantom. Temperature rise up to 70 °C was measured using a MR-compatible fiber-optic thermometer. MR imaging was performed by a 1.5-T scanner utilizing fast gradient echo sequences including a segmented echo planar imaging (seg-EPI) sequence for PRF and the following sequences for T 1 method: fast low-angle shot (FLASH), inversion recovery turbo flash (IRTF), saturation recovery turbo flash (SRTF), and true fast imaging (TRUFI). Temperature-induced change of the pixel values in circular regions of interest, selected on images under the temperature probe tip, was recorded. For each sequence, a calibration constant could be determined to be -0.0088 ± 0.0002 ppm °C(-1) (EPI), -1.15 ± 0.03 °C(-1) (FLASH), -1.49 ± 0.03 °C(-1) (IRTF), -1.21 ± 0.03 °C(-1) (SRTF), and -2.52 ± 0.12 °C(-1) (TRUFI). These constants were evaluated in further LITT experiments in phantom comparing the calculated temperatures with the fiber optic-measured ones; temperature precisions of 0.60 °C (EPI), 0.81 °C (FLASH), 1.85 °C (IRTF), 1.95 °C (SRTF), and 3.36 °C (TRUFI) were obtained. Furthermore, performing the Bland-Altman analysis, temperature accuracy was determined to be 0.23 °C (EPI), 0.31 °C (FLASH), 1.66 °C (IRTF), 1.19 °C (SRTF), and 3.20 °C (TRUFI). In conclusion, the seg-EPI sequence was found to be more convenient for MR temperature imaging of LITT due to its relatively high precision and accuracy. Among the T 1 method sequences, FLASH showed the highest accuracy and robustness.

Short- and Long-Term Outcomes after Radiofrequency Ablation of Osteoid Osteomas.

The aim of this study was to evaluate treatment of osteoid osteomas using bipolar radiofrequency ablation (RFA) and patients' quality of life before and after therapy. We retrospectively evaluated patients who underwent bipolar RFA of osteoid osteomas between 2001 and 2016. We assessed patients' symptoms before and after treatment (four weeks after treatment and long-term) using a questionnaire including severity and quality of pain on a 10-point scale (1 = no pain, 10 = severe pain), motion restrictions, pain-related sleep disorders, and necessary pain medication. In addition, we evaluated technical success, complications, hospitalization length, and patients' satisfaction with treatment. This study included 62 patients (43 [69.4%] males, 26.2 ± 13.2 years). Average nidus size was 5.7 ± 2.6 mm. The rate of technical success was 100%. All RFAs were performed without any complications. One patient showed a recurrence, resulting in a recurrence rate of 1.6%, which was successfully treated by another session of RFA. Average hospitalization length was 1.5 ± 0.5 days. A total of 36 patients (58.1%) participated in the questionnaire, reporting an average pain severity of 8.2 ± 1.6 before RFA compared to 3.4 ± 3.0 four weeks after and an average of 2.1 ± 2.3, 6.6 years after therapy, (both p < 0.001). After therapy, 31 (86.1%) patients had no pain. The majority of patients (n = 34, 94.4%) had reduced or absent motion restriction after therapy (p < 0.001). Patient satisfaction rate was 91.7%. In conclusion, bipolar RFA is a safe and effective treatment modality for osteoid osteomas and improves quality of life by reducing pain severity and motion restrictions.

Magnetic resonance temperature imaging of laser-induced thermotherapy: assessment of fast sequences in ex vivo porcine liver.

AIM: To evaluate magnetic resonance sequences for T(1) and proton resonance frequency (PRF) thermometry during laser-induced thermotherapy (LITT) in liver tissue. MATERIALS & METHODS: During LITT (1064 nm; 30 W; 3-cm diffuser; 2-3 min) in ex vivo porcine liver, temperature was measured (25-70°C) utilizing a fiberoptic thermometer and MRI was performed with a 1.5-T scanner through the following sequences: segmented echo planar imaging (seg-EPI) for the PRF method; fast low-angle shot (FLASH), inversion-recovery turbo FLASH (IRTF), saturation-recovery turbo FLASH (SRTF) and true-fast imaging (TRUFI) for the T(1) method. Phase angle and signal amplitude (regarding PRF/T(1)) was recorded in regions of interest, on images under fiberoptic probe tips. Sequences' thermal coefficients were determined by calibrating phase angle and signal amplitude against temperature and subsequently validated. RESULTS: Coefficients of -0.0089 ± 0.0003 ppm °C(-1) (seg-EPI) and -0.917 ± 0.046, -1.166 ± 0.058, -1.038 ± 0.054 and -1.443 ± 0.118°C(-1) (FLASH, IRTF, SRTF and TRUFI, respectively) were obtained. Precisions of 0.71, 1.34, 2.07, 2.44 and 3.21°C and, through Bland-Altman analysis, accuracies of -0.67, 0.79, 1.65, 1.57 and 2.13°C (seg-EPI, FLASH, IRTF, SRTF and TRUFI, respectively) were determined. CONCLUSION: The PRF method with seg-EPI sequence is preferred for thermometry during LITT owing to higher precision and accuracy. Among T(1)-method sequences, FLASH showed higher accuracy and robustness.