Radiation Exposure and Safety Considerations in Interventional Radiology: Comparison of a Twin Robotic X-ray System to a Conventional Angiography System.

Background/Objectives: To evaluate radiation exposure in standard interventional radiology procedures using a twin robotic X-ray system compared to a state-of-the-art conventional angiography system. Methods: Standard interventional radiology procedures (port implantation, SIRT, and pelvic angiography) were simulated using an anthropomorphic Alderson RANDO phantom (Alderson Research Laboratories Inc. Stamford, CT, USA) on an above-the-table twin robotic X-ray scanner (Multitom Rax, Siemens Healthineers, Forchheim, Germany) and a conventional below-the-table angiography system (Artis Zeego, Siemens Healthineers, Forchheim, Germany). The phantom's radiation exposure (representing the potential patient on the procedure table) was measured with thermoluminescent dosimeters. Height-dependent dose curves were generated for examiners and radiation technologists in representative positions using a RaySafe X2 system (RaySafe, Billdal, Sweden). Results: For all scenarios, the device-specific dose distribution differs depending on the imaging chain, with specific advantages and disadvantages. Radiation exposure for the patient is significantly increased when using the Multitom Rax for pelvic angiography compared to the Artis Zeego, which is evident in the dose progression through the phantom's body as well as in the organ-related radiation exposure. In line with these findings, there is an increased radiation exposure for the performing proceduralist, especially at eye level, which can be significantly minimized by using protective equipment (p < 0.001). Conclusions: In this study, the state-of-the-art conventional below-the-table angiography system is associated with lower radiation dose exposures for both the patient and the interventional radiology physician compared to an above-the-table twin robotic X-ray system for pelvic angiographies. However, in other clinical scenarios (port implantation or SIRT), both devices are suitable options with acceptable radiation exposure.

Transarterial Chemoembolization of Hepatocellular Carcinoma Using Radiopaque Drug-Eluting Embolics: Impact of Embolic Density and Residual Tumor Perfusion on Tumor Recurrence and Survival.

PURPOSE: To evaluate the value of dual-phase parenchymal blood volume (PBV) C-arm mounted cone-beam-CT (CBCT) to enable assessment of radiopaque, doxorubicin-loaded drug-eluting embolics (rDEE) based on the visual degree of embolization, embolic density and residual tumor perfusion as early predictors for tumor recurrence after transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). MATERIAL AND METHODS: Thirty patients (50 HCCs) were prospectively enrolled, underwent cross-sectional imaging before and after TACE using 100-300 µm rDEE and had regular follow-up examinations. Directly before and after the TACE procedure, PBV-CBCT was acquired. The response was evaluated and compared to visual degree of embolization (DE) and embolic density (ED) of rDEE deposits, as well as the presence of residual tumor perfusion (RTP) derived from PBV-CBCT. Outcome was assessed by mid-term tumor response applying mRECIST and patient survival after 12 months. RESULTS: RTP was detected in 16 HCCs and correlated negatively with DE (p = .03*) and ED (p = .0009*). The absence of RTP significantly improved lesion-based mid-term response rates regarding complete response (CR, 30/34 (88%) vs 2/16 (12.5%), p = .0002*), lesion-based complete response rate was 75% (21/28) for DE ≥ 50% vs. 50% (11/22) for DE < 50% (p = .08) and 82% (27/33) for ED ≥ 2 vs. 29% for ED < 2 (5/17), p = .005*). Thirteen patients were treated with re-TACE within 12 months, 11 of which had shown RTP. 12-month survival rate was 93%. CONCLUSION: Residual tumor perfusions as assessed by PBV-CBCT during rDEE-TACE proved to be the best parameter to predict mid-term response. "Level of Evidence: Level 3".

Intraprocedural cone-beam CT with parenchymal blood volume assessment for transarterial chemoembolization guidance: Impact on the effectiveness of the individual TACE sessions compared to DSA guidance alone.

PURPOSE: The objective of this retrospective single centre study was to evaluate the impact of intraprocedural cone-beam CT with parenchymal blood volume assessment (PBV-CBCT) for guidance of transarterial chemoembolization with drug-eluting beads (DEB-TACE) in HCC patients on the effectiveness (local tumour response, survival and number of individual TACE sessions) compared to guidance solely by digital subtraction angiography (DSA). METHOD: n = 179 HCC patients (mean age, 77.4 y) undergoing DEB-TACE, with (n = 28) and without (n = 151) PBV-CBCT, using 100-300 µm microspheres loaded with epirubicin were retrospectively analysed. Tumour response according to mRECIST, overall survival and number of TACE interventions as well as laboratory parameters for liver function and inflammation were recorded. The analysis of the influence of intraprocedural PBV-CBCT was based on matched pair analysis (CBCT n = 28 vs. DSA n = 28). Gender, tumour number, tumour size and HCC risk factors were equally distributed between both groups. RESULTS: Response rates according to mRECIST:CBCT: PD: 7%, SD: 28 %, PR: 46 %, CR: 18 %; DSA: PD: 7 %, SD: 32 %, PR: 39 %, CR: 21 % (p = 0.174). Median OS: CBCT: 44.1 months; DSA: 28.8 months (p = 0.815). Median TACE number: CBCT: 2.0; DSA: 3.0 (p = 0.046). CONCLUSIONS: The use of intraprocedural PBV-CBCT for TACE guidance reduced the number of re-interventions, with no negative effects on tumour response and overall survival. The study findings support the use of PBV-CBCT for DEB-TACE guidance as the improved immediate feedback leads to a considerable increase of the treatment efficiency and helps to avoid unnecessary re-interventions.

Predictive performance of the mHAP-II score in a real-life western cohort with hepatocellular carcinoma following trans-arterial chemoembolisation with drug-eluting beads (DEB-TACE).

OBJECTIVES: To evaluate the predictive performance of the modified hepatoma arterial embolisation prognostic II (mHAP-II) score in a real-life western hepatocellular carcinoma (HCC) cohort treated with drug-eluting bead-TACE and compare the mHAP-II with other scores in this cohort. METHODS: One hundred seventy-nine HCC patients (mean age 77 (± 9) years, 87% male) with one or more drug-eluting bead (DEB)-TACE sessions using 100-300 µm microspheres were retrospectively analysed. Performance analysis of the mHAP-II score was based on Mann-Whitney U tests, the Kaplan-Meier method, log-rank tests, receiver operating characteristics, Akaike's information criterion and Cox regression models. RESULTS: In this population, HCC risk factors were mainly alcohol abuse (31%) and hepatitis C (28%). The median survival of the entire cohort was 29.4 months. mHAP-II classification of the cohort was mHAP-II B (30%), C (41%) and D (23%) respectively. Survival of all subgroups differed significantly from each other (each p < 0.05). Area under the curve for receiver operating characteristic was 0.60 and Akaike's information criterion was 21.8 (p = 0.03), indicating a superior performance of mHAP-II score compared with HAP score and BCLC. Tumour number ≥ two (HR 1.54), alpha-fetoprotein > 400 µg/l (HR 1.14), serum albumin < 3.6 g/dl (HR 1.63) and total bilirubin > 0.9 mg/dl (HR 1.58) contributed significantly in Cox proportional hazards regression (each p < 0.05). CONCLUSION: The mHAP-II score can predict survival outcomes of western HCC patients undergoing DEB-TACE and further subdivide this heterogeneous group; however, certain limitations concerning the predictive power of mHAP-II score must be taken into account. KEY POINTS: • This retrospective study evaluated the predictive performance of the modified hepatoma arterial embolisation prognostic II (mHAP-II) score in a real-life western HCC cohort treated with drug-eluting bead-TACE. • Survival of all mHAP-II subgroups differed significantly, area under the curve for mHAP-II was 0.60 and Akaike's information criterion was 21.8. • The mHAP-II score can predict survival outcomes of western HCC patients undergoing DEB-TACE and further subdivide this heterogeneous group. However, because the study is underpowered, true survival prediction may be more difficult to infer.

Chemosaturation with percutaneous hepatic perfusion of melphalan for liver-dominant metastatic uveal melanoma: a single center experience.

OBJECTIVE: To investigate the outcome and safety data of chemosaturation with percutaneous hepatic perfusion (CS-PHP) of melphalan in patients with liver-dominant metastatic uveal melanoma. MATERIAL AND METHODS: This is a HIPAA compliant, IRB approved, retrospective study. A total of 28 CS-PHPs were performed in 16 individual patients (six men and ten women, median age 63.1 years [range 49.1 to 78.7 years], one to six CS-PHP procedures per patient) for treatment of liver-dominant metastatic uveal melanoma between June, 2015 and December, 2018. All patients received cross-sectional imaging at baseline and during follow-up. CS-PHP was performed with the Hepatic CHEMOSAT® Delivery System (Delcath Systems, Inc., NY, USA) facilitating extracorporeal filtration of hepatic blood for melphalan removal. Ideal body weight-adjusted melphalan doses were administered into the hepatic arteries. Serious adverse events (SAE), progression-free survival based on response criteria in solid tumors, and overall survival were noted. Survival data were analyzed using Kaplan-Meier estimates. RESULTS: Partial response after first CS-PHP was observed in nine patients (60%), stable disease in five patients (33%) and progressive disease in one patient (7%). Median overall survival was 27.4 months (95% CI 4.1 to 35.4 month) after first CS-PHP. Median progression-free survival was 11.1 months after first CS-PHP (95% CI 4.9 to 23.6 months). SAEs were observed in the majority of patients with most SAEs limited to grades one and two. Thirteen SAEs of grades three and four were observed in seven individual patients. No grade five SAE was observed. CONCLUSION: CS-PHP is an efficacious and safe treatment for patients presenting with liver-dominant metastatic uveal melanoma.

Acquired arteriovenous fistula of a finger.

Arteriovenous fistulae are defined as congenital or acquired abnormal direct communications between an artery and a vein leading to abnormal blood circulation. This report describes an unusual manifestation of an acquired peripheral arteriovenous fistula with a high shunt volume of 410 ml/min following a fracture of the 5th finger.

Transarterial Chemoembolization of Hepatocellular Carcinoma Using Radiopaque Drug-Eluting Embolics: How to Pursue Periprocedural Cross-Sectional Imaging?

PURPOSE: To compare different imaging techniques (volume perfusion CT, cone-beam CT, and dynamic gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced dynamic contrast-enhanced MR imaging with golden-angle radial sparse parallel MR imaging) in evaluation of transarterial chemoembolization of hepatocellular carcinoma (HCC) using radiopaque drug-eluting embolics (DEE). MATERIALS AND METHODS: MR imaging and CT phantom investigation of radiopaque DEE was performed. In the clinical portion of the study, 13 patients (22 HCCs) were prospectively enrolled. All patients underwent cross-sectional imaging before and after transarterial chemoembolization using 100-300 µm radiopaque DEE. Qualitative assessment of images using a Likert scale was performed. RESULTS: In the phantom study, CT-related beam-hardening artifacts were markedly visible at a concentration of 12% (v/v) radiopaque DEE; MR imaging demonstrated no significant detectable signal intensity changes. Imaging obtained before transarterial chemoembolization showed no significant difference regarding tumor depiction. Visualization of tumor feeding arteries was significantly improved with volume perfusion CT (P < .001) and cone-beam CT (P = .002) compared with MR imaging. Radiopaque DEE led to significant decrease in tumor depiction (P = .001) and significant increase of beam-hardening artifacts (P = .012) using volume perfusion CT before versus after transarterial chemoembolization. Greater residual arterial tumor enhancement was detected with MR imaging (10 HCCs) compared with volume perfusion CT (8 HCCs) and cone-beam CT (6 HCCs). CONCLUSIONS: Using radiopaque DEE, the imaging modalities provided comparable early treatment assessment. In HCCs with dense accumulation of radiopaque DEE, treatment assessment using volume perfusion CT or cone-beam CT may be impaired owing to resulting beam-hardening artifacts and contrast stasis. Dynamic contrast-enhanced MR imaging may add value in detection of residual arterial tumor enhancement.

Image quality of arterial phase and parenchymal blood volume (PBV) maps derived from C-arm computed tomography in the evaluation of transarterial chemoembolization.

BACKGROUND: To evaluate the benefits of arterial phase imaging and parenchymal blood volume (PBV) maps acquired by C-arm computed tomography during TACE procedure in comparison to cross-sectional imaging (CSI) using CT or MRI. METHODS: From January 2014 to December 2016, a total of 29 patients with HCC stage A or B (mean age 65 years; range 47 to 81 years, 86% male) were included in this study. These patients were referred to our department for TACE treatment and received peri-interventional C-arm CT. Dual phase findings of each lesion in terms of overall image quality, conspicuity, tumor size and feeding arteries were compared between arterial phase imaging and PBV using 5-point semi-quantitative Likert-scale, whereby pre-interventional CSI served as reference standard. RESULTS: A significantly higher overall image quality of the PBV maps compared to arterial phase C-arm CT acquisitions (4.34 (±0.55) vs. 3.93 (±0.59), p = 0.0032) as well as a higher conspicuity of HCC lesions (4.27 ± 0.74 vs. 3.83 ± 1.08, p < 0.0001) was observed. Arterial phase imaging led to an overestimation of tumor size (mean size, 26.5 ± 15.9 mm) compared to PBV (24.9 ± 15.2 mm, p = 0.0004) as well as CSI (25.2 ± 15.1 mm), p = 0.021). Regarding detectability of tumor feeding arterial vessels, significantly more feeding vessels were detected in arterial phase C-arm CT (n = 1.67 ± 0.92 vessels) compared to PBV maps (n = 1.27 ± 0.63 vessels) (p = 0.0001). One lesion was missed in pre-interventional CT imaging, but detected by C-arm CT. CONCLUSION: The combination of PBV maps and arterial phase images acquired by C-arm CT during TACE procedure enables precise detection of the majority of HCC lesions and tumor feeding arteries and has therefore the potential to improve patient outcome.

A Prospective Study of Quantitative SPECT/CT for Evaluation of Lung Shunt Fraction Before SIRT of Liver Tumors.

The lung shunt fraction (LSF) is estimated using 99mTc-macroaggregated albumin (99mTc-MAA) imaging before selective internal radiotherapy (SIRT) of the liver to reduce the risk of pulmonary irradiation. Generally, planar scans are acquired after injection of 99mTc-MAA into the hepatic artery. However, the validity of this approach is limited by differences in attenuation between liver and lung tissue as well as inaccurate segmentation of the organs. The aim of this study was to evaluate quantitative SPECT/CT for LSF assessment in a prospective clinical cohort. Methods: Fifty consecutive patients intended to undergo SIRT were imaged within 1 h after injection of 99mTc-MAA using a SPECT/CT γ-camera. Planar scans of the lung and liver region were acquired in anterior and posterior views, followed by SPECT/CT scans of the thorax and abdomen. Emission data were corrected for scatter, attenuation, and resolution recovery using dedicated software. To quantify the radioactivity concentration in the lung, liver, urinary bladder and remainder of the thoracoabdominal body, volumes of interest were defined on the SPECT/CT images. 99mTc-MAA concentrations were calculated as percentage injected dose (%ID). Results: Mean 99mTc-MAA uptake in liver and lung accounted for only 79 %ID, whereas 13.1 %ID was present in the remainder of the body. In all patients, LSF as calculated from planar scans accounted for a median of 6.8% (range, 3.4%-32.3%), whereas the SPECT/CT quantitation revealed significantly lower LSF estimates, at a median of 1.9% (range, 0.8%-15.7%) (P < 0.0001, Wilcoxon test). On the basis of planar imaging, dose reduction or even contraindications to SIRT had to be considered in 10 of 50 patients, as their LSF was calculated at 10% or more. In contrast, SPECT/CT quantitation showed substantial shunting in only 2 of the 50 patients. Conclusion: Quantitative SPECT/CT reveals that the LSF is considerably lower than shown on planar imaging. Thus, the resulting dose to the lung parenchyma may be less than conventionally assumed. However, the safety of the SPECT/CT-derived dose range will have to be evaluated.

INFLUENCE OF AGE ON PARAMETERS FOR FEMOROACETABULAR IMPINGEMENT AND HIP DYSPLASIA IN X-RAYS.

OBJECTIVE: While several radiographic parameters have been established to describe the geometry and pathology of the hip, their reference values and clinical significance remain a matter of dispute. The present study tests the hypothesis that age has a relevant impact on radiographic hip parameters. METHOD: Pelvic antero-posterior views were measured for CE angle, Sharp's angle, acetabular depth-to-width ratio, femoral head extrusion index, roof obliquity, caput-collum-diaphyseal (CCD) angle, and Murray's femoral head ratio, and the values obtained were correlated with age. RESULTS: Significant weak and moderate linear correlations (all Ps<0.001) were observed between age and CE angle (ρ=0.31), Sharp's angle (ρ=-0.38), extrusion index (ρ=-0.22), CCD angle (ρ=-0.15), depth-to-width ratio (ρ=-0.38), and roof obliquity (ρ=-0.19), while Murray's femoral head ratio (ρ=0.05; P=0.274) was not associated with age. Interestingly, the parameters describing the acetabulum all showed a relevant increase in coverage with age, leading to CE-angles well beyond 40° and a Sharp's angle below 35° in a large portion of asymptomatic older adults. CONCLUSION: While a decrease in CCD angle with age is described in most orthopedic textbooks, the changes observed with age in acetabular geometry far exceed those measured at the femoral head-neck junction. We recommend considering these alterations that may be attributable to age when formulating a radiographic diagnosis. Level of Evidence III, Diagnostic Studies - Investigating a Diagnostic Test.

OBJETIVO: Embora tenham sido estabelecidos vários parâmetros radiográficos para descrever a geometria e a patologia do quadril, seus valores de referência e significância clínica continuam sendo uma questão controversa. O presente estudo testa a hipótese de que a idade tem impacto relevante sobre os parâmetros radiográficos do quadril. MÉTODO: As vistas pélvicas anteroposteriores foram medidas quanto ao ângulo CE, ângulo de Sharp, proporção entre profundidade e largura acetabular, índice de extrusão da cabeça do fêmur, obliquidade do lábio do acetábulo (teto), ângulo cabeça-colo-diafisário (CCD) e razão da cabeça do fêmur de Murray e os valores obtidos foram correlacionados com a idade. RESULTADOS: Foram observadas correlações lineares significantes, fracas e moderadas (todos os P < 0,001) entre idade e ângulo CE (ρ = 0,31), ângulo de Sharp (ρ = -0,38), índice de extrusão da cabeça do fêmur (ρ = -0,22), ângulo CCD (ρ = -0,15), proporção entre profundidade e largura acetabular (ρ = -0,38) e obliquidade do lábio do acetábulo (ρ = -0,19), enquanto a razão da cabeça do fêmur de Murray (ρ = 0,05; P = 0,274) não foi associada à idade. Curiosamente, todos os parâmetros que descrevem o acetábulo mostraram um aumento relevante de cobertura com idade, levando a ângulos CE bem além de 40° e ângulos de Sharp abaixo de 35° em uma grande parcela de idosos assintomáticos. CONCLUSÃO: Embora a diminuição do ângulo CCD com a idade seja descrita na maioria dos livros didáticos de ortopedia, as alterações na geometria acetabular observadas com a idade ultrapassam, de longe, as medidas na junção entre cabeça e colo do fêmur. Recomendamos considerar essas alterações que podem ser atribuídas à idade ao formular um diagnóstico radiográfico. Nível de Evidência III, Estudos Diagnósticos - Investigação de um Exame para Diagnóstico.

Influence of age on parameters for femoroacetabular impingement and hip dysplasia in x-rays / Influência da idade sobre os parâmetros para impacto femoroacetabular e diplasia do quadril em radiografias

ABSTRACT Objective: While several radiographic parameters have been established to describe the geometry and pathology of the hip, their reference values and clinical significance remain a matter of dispute. The present study tests the hypothesis that age has a relevant impact on radiographic hip parameters. Method: Pelvic antero-posterior views were measured for CE angle, Sharp's angle, acetabular depth-to-width ratio, femoral head extrusion index, roof obliquity, caput-collum-diaphyseal (CCD) angle, and Murray's femoral head ratio, and the values obtained were correlated with age. Results: Significant weak and moderate linear correlations (all Ps<0.001) were observed between age and CE angle (ρ=0.31), Sharp's angle (ρ=-0.38), extrusion index (ρ=-0.22), CCD angle (ρ=-0.15), depth-to-width ratio (ρ=-0.38), and roof obliquity (ρ=-0.19), while Murray's femoral head ratio (ρ=0.05; P=0.274) was not associated with age. Interestingly, the parameters describing the acetabulum all showed a relevant increase in coverage with age, leading to CE-angles well beyond 40° and a Sharp's angle below 35° in a large portion of asymptomatic older adults. Conclusion: While a decrease in CCD angle with age is described in most orthopedic textbooks, the changes observed with age in acetabular geometry far exceed those measured at the femoral head-neck junction. We recommend considering these alterations that may be attributable to age when formulating a radiographic diagnosis. Level of Evidence III, Diagnostic Studies - Investigating a Diagnostic Test.

RESUMO Objetivo: Embora tenham sido estabelecidos vários parâmetros radiográficos para descrever a geometria e a patologia do quadril, seus valores de referência e significância clínica continuam sendo uma questão controversa. O presente estudo testa a hipótese de que a idade tem impacto relevante sobre os parâmetros radiográficos do quadril. Método: As vistas pélvicas anteroposteriores foram medidas quanto ao ângulo CE, ângulo de Sharp, proporção entre profundidade e largura acetabular, índice de extrusão da cabeça do fêmur, obliquidade do lábio do acetábulo (teto), ângulo cabeça-colo-diafisário (CCD) e razão da cabeça do fêmur de Murray e os valores obtidos foram correlacionados com a idade. Resultados: Foram observadas correlações lineares significantes, fracas e moderadas (todos os P < 0,001) entre idade e ângulo CE (ρ = 0,31), ângulo de Sharp (ρ = -0,38), índice de extrusão da cabeça do fêmur (ρ = -0,22), ângulo CCD (ρ = -0,15), proporção entre profundidade e largura acetabular (ρ = -0,38) e obliquidade do lábio do acetábulo (ρ = -0,19), enquanto a razão da cabeça do fêmur de Murray (ρ = 0,05; P = 0,274) não foi associada à idade. Curiosamente, todos os parâmetros que descrevem o acetábulo mostraram um aumento relevante de cobertura com idade, levando a ângulos CE bem além de 40° e ângulos de Sharp abaixo de 35° em uma grande parcela de idosos assintomáticos. Conclusão: Embora a diminuição do ângulo CCD com a idade seja descrita na maioria dos livros didáticos de ortopedia, as alterações na geometria acetabular observadas com a idade ultrapassam, de longe, as medidas na junção entre cabeça e colo do fêmur. Recomendamos considerar essas alterações que podem ser atribuídas à idade ao formular um diagnóstico radiográfico. Nível de Evidência III, Estudos Diagnósticos - Investigação de um Exame para Diagnóstico.

Results of a prospective clinical study on the diagnostic performance of standard magnetic resonance imaging in comparison to a combination of 3T MRI and additional CT imaging in Kienböck's disease.

PURPOSE: This prospective clinical study examined standard wrist magnetic resonance imaging (MRI) examinations and the incremental value of computed tomography (CT) in the diagnosis of Kienböck's disease (KD) with regard to reliability and precision in the different diagnostic steps during diagnostic work-up. MATERIALS AND METHODS: Sixty-four consecutive patients referred between January 2009 and January 2014 with positive initial suspicion of KD according to external standard wrist MRI were prospectively included (step one). Institutional review board approval was obtained. Clinical examination by two handsurgeons were followed by wrist radiographs (step two), ultrathin-section CT, and 3T contrast-enhanced MRI (step three). Final diagnosis was established in a consensus conference involving all examiners and all examinations results available from step three. RESULTS: In 12/64 patients, initial suspicion was discarded at step two and in 34/64 patients, the initial suspicion of KD was finally discarded at step three. The final external MRI positive predictive value was 47%. The most common differential diagnoses at step three were intraosseous cysts (n=15), lunate pseudarthrosis (n=13), and ulnar impaction syndrome (n=5). A correlation between radiograph-based diagnoses (step two) with final diagnosis (step three) showed that initial suspicion of stage I KD had the lowest sensitivity for correct diagnosis (2/11). Technical factors associated with a false positive external MRI KD diagnosis were not found. CONCLUSION: Standard wrist MRI should be complemented with thin-section CT, and interdisciplinary interpretation of images and clinical data, to increase diagnostic accuracy in patients with suspected KD.

CT-perfusion measurements in pancreatic carcinoma with different kinetic models: Is there a chance for tumour grading based on functional parameters?

BACKGROUND: To evaluate the interchangeability of perfusion parameters obtained with help of models used for post-processing of perfusion-CT images in pancreatic adenocarcinoma and to determine the mean values and ranges of perfusion in different tumour gradings. METHODS: Perfusion-CT imaging was performed prospectively in 48 consecutive patients with pancreatic adenocarcinoma. In 42 patients biopsy-proven tumor grading was available (4 × G1/24 × G2/14 × G3/6× unknown). Images were post-processed using a model based on the maximum-slope (MS) approach (blood flow-BFMS) + Patlak analysis (P) (blood volume [BVP] and permeability [k-transP]), as well as a model with deconvolution-based (D) analysis (BFD, BVD and k-transD). 50 mL contrast agent were applied with a delay time of 7 s. Perfusion parameters were compared using intraclass correlation coefficient (ICC), the Wilcoxon matched-pairs test and Bland-Altman plots. RESULTS: Forty eight VOIs of tumours were outlined and analysed. Moderate to good ICC values were found for the perfusion parameters (ICC = 0.62-0.75). Wilcoxon matched-pairs revealed significantly lower values (P < .001 and 0.008), for the BF and BV values obtained using the maximum-slope approach + Patlak analysis compared to deconvolution based analysis. For k-trans measurement, deconvolution revealed significantly lower values (P < 0.001). Different histologic subgroups (G1-G3) did not show significantly different functional parameters. CONCLUSION: There were significant differences in the perfusion parameters obtained using the different calculation methods, and therefore these parameters are not directly interchangeable. However, the magnitude of pairs of parametric values is in constant relation to each other enabling the use of any of these methods. VPCT parameters did not allow for histologic classification.

C-arm computed tomography and volume perfusion computed tomography (VPCT)-based assessment of blood volume changes in hepatocellular carcinoma in prediction of midterm tumor response to transarterial chemoembolization: a single center retrospective trial.

BACKGROUND: This study aims to evaluate immediate changes in perfusion parameters in hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE) in C-arm computed tomography (CT) and volume perfusion CT (VPCT) and prediction of midterm tumor response. METHODS: Twenty-five patients (median age 66, range 61 to 75 years) with 62 HCC lesions undergoing TACE received immediate pre- and post-interventional assessment by C-arm CT and VPCT. Cross-sectional imaging was analyzed at baseline and approximately 12 weeks after TACE according to modified RECIST criteria. Outcome was defined as objective response (OR, > 30 % reduction of viable tumor) or non-OR. Perfusion parameters were evaluated in C-arm CT [parenchymal blood volume (PBV)] and VPCT [blood volume (BV) and blood flow (BF)]. Ratios of perfusion parameters before and after TACE within the tumor and the non-affected liver parenchyma were calculated. RESULTS: Correlation between tumor PBV and BV revealed a moderate correlation (rho = 0.45, p = 0.005). In non-affected liver parenchyma, a significant decrease in PBV was seen, compared to a significant increase in BF and BV. Perfusion ratios in HCC lesions were significantly (p < 0.05) increased in OR group compared to non-OR patients in C-arm CT and VPCT: PBV ratio (0.95 (0.06) to 0.67 (0.38), BV ratio 0.63 (0.34) to 0.15 (0.6), and BF ratio 0.6 (0.32) to 0.22 (0.51). Logistic regression including PBV and BF allowed prediction of OR (sensitivity 88 %/specificity of 83 %). CONCLUSIONS: Perfusion parameters acquired by C-arm CT and VPCT cannot simply be substituted by each other, but show similar capability in prediction of midterm tumor response.

Correlation of magnetic resonance signal characteristics and perfusion parameters assessed by volume perfusion computed tomography in hepatocellular carcinoma: Impact on lesion characterization.

AIM: To find out if magnetic resonance (MR)-signal characteristics of hepatocellular carcinomas (HCC) correlate with perfusion parameters assessed by volume perfusion computed tomography (VPCT). METHODS: From October 2009 to January 2014, 26 (mean age, 69.3 years) patients with 36 HCC lesions who underwent both VPCT and MR liver imaging were analysed. We compared signal intensity in the T1w- and T2w-images and wash-in/wash-out kinetics on post-contrast MR images with mean values of blood flow (BF, mL/100 mL per minute), blood volume (BV, mL/100 mL), k-trans (mL/100 mL per minute), arterial liver perfusion (mL/100 mL per minute), portal venous perfusion and hepatic perfusion index (HPI, %) obtained by VPCT. Signal intensity on magnetic resonance imaging (MRI) was classified hyper/iso/hypointense compared with surrounding liver parenchyma. RESULTS: Signal intensity on native T1w- and T2w-images was hyper/iso/hypo in 4/16/16 and 21/14/1 lesions, respectively. Wash-in and wash-out contrast kinetics were found on MRI in 33 of 36 lesions (91.7%) and 25 of 36 lesions (69.4%), respectively. The latter was observed significantly more often in higher graded lesions (P < 0.005). HPI was 94.7% ± 6.5%. There was no significant relationship between lesion's MR-signal intensity, MR signal combinations, size and any of the VPCT-perfusion parameters. However HPI was constantly high in all HCC lesions. CONCLUSION: VPCT parameters add limited value to MR-lesion characterization. However in HCC lesions with atypical MR signal characteristics HPI can add a parameter to ensure HCC diagnosis.

Parenchymal Blood Volume Assessed by C-Arm-Based Computed Tomography in Immediate Posttreatment Evaluation of Drug-Eluting Bead Transarterial Chemoembolization in Hepatocellular Carcinoma.

OBJECTIVES: The aim of this study was to assess clinical utility of the quantitative perfusion parameter called parenchymal blood volume (PBV), as derived from C-arm-based computed tomography (CT), for immediate posttreatment assessment of drug-eluting bead (DEB) transarterial chemoembolization (TACE) in hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Twenty-four patients with early- or intermediate-stage HCC received DEB-TACE. A total of 52 HCC lesions were treated and assessed by C-arm CT before and after intervention. C-arm CT consisted of nonenhanced and contrast-enhanced acquisitions; from these, PBV maps were reconstructed. Lesion diameter, maximum PBV, and unenhanced parenchyma density were assessed before and after treatment. Diameter of visible contrast media deposits as well as residual vascularization was assessed after delivery of DEB. All patients underwent follow-up using cross-sectional imaging. All assessed lesions were evaluated concerning modified Response Evaluation Criteria in Solid Tumors for HCC. RESULTS: All treated lesions showed significant decrease in PBV after DEB-TACE (mean difference, -15.61 mL/100 mL, P < 0.0001). Eleven lesions showed residual tumoral perfusion in PBV maps associated with an unfavorable outcome compared with completely treated lesions in terms of a lower tumor shrinkage over time (-0.02 ± 0.49 vs -0.76 ± 0.38; P < 0.0001). A contrast media deposit was seen in 78% of treated HCC lesions with a tendency toward better visibility in encapsulated lesions. Nonenhanced parenchyma density was significantly higher in all treated segments (149.69 ± 58.6 vs 68.42 ± 18.04, P < 0.0001). CONCLUSIONS: Parenchymal blood volume values as derived from C-arm CT acquisitions in combination with nonenhanced and contrast-enhanced C-arm CT images are useful in posttreatment assessment of DEB-TACE in HCC. Residual tumor perfusion in PBV maps have predictive potential for mid-term tumor response in HCC and could allow a more individualized treatment schedule for DEB-TACE in HCC patients.

C-arm computed tomography parenchymal blood volume measurement in evaluation of hepatocellular carcinoma before transarterial chemoembolization with drug eluting beads.

BACKGROUND: C-arm computed tomography (CT) guided intervention is an increasingly applied technique in transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). The aim of this study was to analyse the value of parenchymal blood volume (PBV) maps acquired during C-arm CT acquisition, for pre-treatment evaluation and planning of TACE in HCC patients. METHODS: A total of 64 HCC lesions in 29 patients (median age, 73 years, range, 62-77 years) were included in this retrospective study. All patients received cross-sectional imaging (MRI or CT) prior to TACE and C-arm CT PBV measurement acquisition before performing TACE. Results of cross-sectional imaging regarding the number of HCC lesions and maximum diameter were compared to PBV-maps. Number of lesions and tumour feeding vessels detected in PBV-maps were compared to conventional angiography. Results of PBV were analysed concerning different tumour morphologies (pre-treated, encapsulated and diffuse). RESULTS: Pre-interventional cross-sectional imaging and PBV maps showed an excellent agreement in lesion diameter (p = 0.88, MD = -0.28 mm) and number of detected lesions (κ = 1.0). Compared to conventional angiography, PBV maps showed an increased number of detected lesions (κ = 0.77, p = 0.001) and tumour feeding vessels (κ = 0.71, p < 0.0001). Diffuse HCC lesion revealed a significantly lower PBV compared to encapsulated lesions (p = 0.0001). CONCLUSIONS: C-arm CT acquired PBV measurements detect HCC tumours with a lesion detectability comparable to pre-interventional cross-sectional imaging. Furthermore, this technique facilitates TACE, allowing a more precise localization of HCC lesions and tumour feeding vessels compared to conventional angiography. Additionally, calculated PBV values enable a real time quantitative assessment of tumour perfusion.

Portal vein recanalization and embolization of the transsplenic puncture tract using an Amplatzer® vascular plug: a case report.

BACKGROUND: A transsplenic access for the catheterization of the portal venous system to treat a portal vein thrombosis and/or stenosis entails the risk of intra-abdominal or intrasplenic bleeding complications and has to be seen as an approach of last resort. This is one of few reported cases in the literature where a transsplenic puncture tract was successfully embolized using an Amplatzer® vascular plug 4 (8 mm; St. Jude Medical). CASE PRESENTATION: This is the case report of a 58 years old Caucasian male patient who had received right sided extended hemihepatectomy with partial resection of the portal vein due to hilar cholangiocarcinoma three years ago. The patient suffered from portal hypertension with difficult controllable bleeding of esophageal varices due to chronically progressive thrombosis of the portal vein caused by chronic anastomosis stenosis of the reconstructed left portal vein branch (confirmed in a Magnetic Resonance Imaging (MRI) examination 6 months after the portal vein reconstruction). A transsplenic access (6 French) was chosen to allow recanalization of the portal vein, stent-angioplasty of the anastomosis and coiling of the gastric varices. The transsplenic tract was successfully embolized with an Amplatzer® Vascular Plug 4 and gelfoam pledgets. CONCLUSION: Amplatzer® Vascular plugs in combination with gelatin sponges can be used to efficiently and precisely seal transsplenic puncture sites.

Imaging of HCC-Current State of the Art.

Early diagnosis of hepatocellular carcinoma (HCC) is crucial for optimizing treatment outcome. Ongoing advances are being made in imaging of HCC regarding detection, grading, staging, and also treatment monitoring. This review gives an overview of the current international guidelines for diagnosing HCC and their discrepancies as well as critically summarizes the role of magnetic resonance imaging (MRI) and computed tomography (CT) techniques for imaging in HCC. The diagnostic performance of MRI with nonspecific and hepatobililiary contrast agents and the role of functional imaging with diffusion-weighted imaging will be discussed. On the other hand, CT as a fast, cheap and easily accessible imaging modality plays a major role in the clinical routine work-up of HCC. Technical advances in CT, such as dual energy CT and volume perfusion CT, are currently being explored for improving detection, characterization and staging of HCC with promising results. Cone beam CT can provide a three-dimensional analysis of the liver with tumor and vessel characterization comparable to cross-sectional imaging so that this technique is gaining an increasing role in the peri-procedural imaging of HCC treated with interventional techniques.

Transarterial chemoembolization using drug eluting beads and subsequent percutaneous MR-guided radiofrequency ablation in the therapy of intermediate sized hepatocellular carcinoma.

OBJECTIVE: To evaluate safety, efficacy, survival and recurrence-free survival of transarterial chemoembolization (TACE) with drug eluting (DC) beads combined with MR-guided radiofrequency (RF) ablation for the treatment of hepatocellular carcinomas (HCC) larger than 3 cm. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board. 20 patients (69.6 years ± SD 8.8) with HCC underwent DC Bead TACE and subsequent MR-guided RF ablation. Treatment interval varied between 5 and 15 days. Mean HCC diameter was 39 mm ± SD 7 mm (range 31-50mm). Rates of recurrence-free survival and overall survival were estimated using the Kaplan-Meier method. RESULTS: Technical success rate, primary and secondary technical effectiveness rate were 100%, 90% and 95%, respectively. Local tumour progression developed in one patient. Cumulative survival rates at 1, 3 and 5 years were 90% (Confidence Interval [CI]: 67%-97%), 50% (CI: 29%-70%), 27% (CI: 11%-51%) respectively. Median survival time was 37.4 months. During follow up (mean: 39.1 months ± SD 22.4; range 5-84 months), tumour progression in untreated liver developed in 14 cases. Cumulative recurrence-free survival rates at 1, 3 and 5 years were 48% (CI: 27-69%), 16% (5-39%), 16% (5-39%) respectively. Median recurrence-free survival time was 10.7 months. One major complication occurred due to misdiagnosed local recurrence. CONCLUSION: In conclusion, we demonstrated that MR-guided RF ablation with subsequent DC Bead TACE is safe and effective in local tumour control in patients with intermediate sized HCC.