Portal vein thrombosis and arterioportal shunts: effects on tumor response after chemoembolization of hepatocellular carcinoma

AIM

To evaluate the effect of portal vein thrombosis and arterioportal shunts on local tumor response in advanced cases of unresectable hepatocellular carcinoma treated by transarterial chemoembolization.

METHODS

A retrospective study included 39 patients (mean age: 66.4 years, range: 45-79 years, SD: 7) with unresectable hepatocellular carcinoma (HCC) who were treated with repetitive transarterial chemoembolization (TACE) in the period between March 2006 and October 2009. The effect of portal vein thrombosis (PVT) (in 19 out of 39 patients), the presence of arterioportal shunt (APS) (in 7 out of 39), the underlying liver pathology, Child-Pugh score, initial tumor volume, number of tumors and tumor margin definition on imaging were correlated with the local tumor response after TACE. The initial and end therapy local tumor responses were evaluated according to the response evaluation criteria in solid tumors (RECIST) and magnetic resonance imaging volumetric measurements.

RESULTS

The treatment protocols were well tolerated by all patients with no major complications. Local tumor response for all patients according to RECIST criteria were partial response in one patient (2.6%), stable disease in 34 patients (87.1%), and progressive disease in 4 patients (10.2%). The MR volumetric measurements showed that the PVT, APS, underlying liver pathology and tumor margin definition were statistically significant prognostic factors for the local tumor response (P = 0.018, P = 0.008, P = 0.034 and P = 0.001, respectively). The overall 6-, 12- and 18-mo survival rates from the initial TACE were 79.5%, 37.5% and 21%, respectively.

CONCLUSION

TACE may be exploited safely for palliative tumor control in patients with advanced unresectable HCC; however, tumor response is significantly affected by the presence or absence of PVT and APS.

Image fusion in dual energy computed tomography for detection of various anatomic structures--effect on contrast enhancement, contrast-to-noise ratio, signal-to-noise ratio and image quality

OBJECTIVE

The purpose of this study was to evaluate image fusion in dual energy computed tomography for detecting various anatomic structures based on the effect on contrast enhancement, contrast-to-noise ratio, signal-to-noise ratio and image quality.

MATERIAL AND METHODS

Forty patients underwent a CT neck with dual energy mode (DECT under a Somatom Definition flash Dual Source CT scanner (Siemens, Forchheim, Germany)). Tube voltage: 80-kV and Sn140-kV; tube current: 110 and 290 mAs; collimation-2×32×0.6 mm. Raw data were reconstructed using a soft convolution kernel (D30f). Fused images were calculated using a spectrum of weighting factors (0.0, 0.3, 0.6 0.8 and 1.0) generating different ratios between the 80- and Sn140-kV images (e.g. factor 0.6 corresponds to 60% of their information from the 80-kV image, and 40% from the Sn140-kV image). CT values and SNRs measured in the ascending aorta, thyroid gland, fat, muscle, CSF, spinal cord, bone marrow and brain. In addition, CNR values calculated for aorta, thyroid, muscle and brain. Subjective image quality evaluated using a 5-point grading scale. Results compared using paired t-tests and nonparametric-paired Wilcoxon-Wilcox-test.

RESULTS

Statistically significant increases in mean CT values noted in anatomic structures when increasing weighting factors used (all P≤0.001). For example, mean CT values derived from the contrast enhanced aorta were 149.2±12.8 Hounsfield Units (HU), 204.8±14.4 HU, 267.5±18.6 HU, 311.9±22.3 HU, 347.3±24.7 HU, when the weighting factors 0.0, 0.3, 0.6, 0.8 and 1.0 were used. The highest SNR and CNR values were found in materials when the weighting factor 0.6 used. The difference CNR between the weighting factors 0.6 and 0.3 was statistically significant in the contrast enhanced aorta and thyroid gland (P=0.012 and P=0.016, respectively). Visual image assessment for image quality showed the highest score for the data reconstructed using the weighting factor 0.6.

CONCLUSION

Different fusion factors used to create images in DECT cause statistically significant differences in CT value, SNR, CNR and image quality. Best results obtained using the weighting factor 0.6 for all anatomic structures used in this study.

MR-compatible assistance system for biopsy in a high-field-strength system: initial results in patients with suspicious prostate lesions

PURPOSE

To examine the feasibility and safety of magnetic resonance (MR)-guided biopsy by using a transgluteal approach in patients with suspicious prostate lesions by using an MR-compatible robotic system and a 1.5-T MR system.

MATERIALS AND METHODS

The study was approved by the institutional review board of University Frankfurt, and informed consent was obtained from each patient. A total of 20 patients (age range, 57.8-71.9 years; mean age, 65.1 years) underwent biopsy in a closed-bore high-field-strength MR system. Biopsy was performed with an MR-compatible pneumatically driven robotic system. T1-weighted gradient-echo fast low-angle shot and T2-weighted true fast imaging with steady-state precession sequences were used to plan and guide the intervention with a transgluteal access on the external planning computer of the assistance system. The system calculated the trajectory and then moved the guiding arm to the insertion point. The cannula was advanced manually, and biopsies were performed with the coaxial technique by using a 15-gauge pencil tip needle. Intervention time, complications, and biopsy findings were documented.

RESULTS

The MR-compatible robotic system did not interfere with image quality, nor did MR imaging cause dysfunction of the robot. In one patient, the interventionist caused a fail-safe system shutdown. This was due to inadvertent displacement of the guiding arm during cannula insertion. This problem was solved by increasing the displacement threshold. Accurate coaxial cannula biopsy could be performed in all subsequent patients. Sufficient histopathologic assessment was performed in 19 patients. Insufficient material was retrieved in the patient who experienced fail-safe system shutdown. The median intervention time was 39 minutes (23-65 minutes). No procedure-related complications were observed.

CONCLUSION

Preliminary results indicate that MR-guided robot-assisted biopsy is feasible and can be performed safely with highly accurate cannula placement.

MRI of the prostate: interobserver agreement compared with histopathologic outcome after radical prostatectomy

BACKGROUND

The purpose of this study was to evaluate interobserver agreement of prostatic MRI in assessing the performance of staging prostate carcinoma in comparison with histopathologic step section prostate specimens.

METHODS

We retrospectively evaluated 46 patients who underwent prostatic MRI examination at 1.5 T MRI and "subsequently" radical prostatectomy. All MR-images were reevaluated by two different experienced radiologists (15 and 1.5 years of experience) with special focus on T2/T3 differentiation. Both radiologists were not aware of the patient's clinical data, except that the patient had prostate cancer. These findings were compared with histopathologic whole mount step section prostate specimens, which served as the "gold standard". Fourfold tables were created to calculate sensitivity, specificity, positive and negative predictive values and efficiency for T2/T3 differentiation. Cohen's kappa was calculated to measure inter-rater agreement.

RESULTS

Twenty-eight patients were diagnosed with organ defined cancer (T2), 18 patients were staged with extracapsular extension (T3), and thereof 7 patients were staged with seminal vesicle invasion (T3b) by the pathologists. The experienced reader reached a sensitivity of 77.78% (95%-CI 52.36%; 93.59%) and specificity of 92.86% (95%-CI 76.50%; 99.12%) for T2/T3 differentiation, the less experienced reader however achieved a sensitivity of 33.33% (95%-CI 13.34%; 59.01%) and specificity of 71.43% (95%-CI 51.33%; 86.78%). The Cohen's kappa for inter-rater reliability for differentiation between T2 and T3 stage was κ=0.0129.

CONCLUSIONS

Evaluation of prostatic MR imaging requires lengthy experience for accurate interpretation and staging. While a highly experienced reader can achieve good correlation with histopathology even without utilization of functional MR imaging, a less experienced reader with theoretical knowledge falls short of expectation.

[Chemoperfusion and embolization in the treatment of liver metastases]

Presentation of techniques and procedures for regional chemotherapy in the treatment of unresectable liver metastases from different primary tumors as a modality of interdisciplinary therapy management. Such transarterial therapy methods include hepatic arterial infusion (HAI), transarterial chemoembolization (TACE), chemoembolization with cytostatic-loaded microspheres (DEBs), transarterial embolization (TAE) and selective internal radiation therapy (SIRT). Regional chemotherapy procedures in the treatment of liver metastases represent a minimally invasive treatment option that can be successfully combined with surgical resection and/or radiofrequency (RFA), laser-induced thermotherapy (LITT), microwave ablation (MWA). These procedures allow optimization of the local control rate with strictly intrahepatic processes and lead to increased survival rates without any quality of life restriction.

Efficacy and safety of sorafenib in advanced hepatocellular carcinoma under daily practice conditions

Sorafenib has recently been shown to be effective for the treatment of advanced hepatocellular carcinoma in randomized controlled trials. Here, we report the experience with sorafenib in 25 patients with advanced HCC under daily practice conditions. Tolerance to sorafenib was acceptable and side effects were manageable, although the ECOG performance status was reduced in all patients. The most prevalent grade 2/3 side effects were fatigue (40%) and diarrhea (24%), and withdrawal from therapy occurred in 29% of patients. Disease stabilization was documented in 60% of patients. The median treatment time was 2.7 months and overall survival was 11.0 months. No significant serum alpha-fetoprotein decline was noted at the time of the first radiological control in a subgroup of patients with baseline levels >50 ng/ml who achieved stable disease. In conclusion, in daily practice sorafenib is safe and disease stabilization can be achieved in the majority of patients. However, intolerance to sorafenib can affect treatment adherence substantially.

Accuracy of cardiovascular magnetic resonance in myocarditis: comparison of MR and histological findings in an animal model

BACKGROUND

Because endomyocardial biopsy has low sensitivity of about 20%, it can be performed near to myocardium that presented as late gadolinium enhancement (LGE) in cardiovascular magnetic resonance (CMR). However the important issue of comparing topography of CMR and histological findings has not yet been investigated. Thus the current study was performed using an animal model of myocarditis.

RESULTS

In 10 male Lewis rats experimental autoimmune myocarditis was induced, 10 rats served as control. On day 21 animals were examined by CMR to compare topographic distribution of LGE to histological inflammation. Sensitivity, specificity, positive and negative predictive values for LGE in diagnosing myocarditis were determined for each segment of myocardium. Latter diagnostic values varied widely depending on topographic distribution of LGE and inflammation as well as on the used CMR sequence. Sensitivity of LGE was up to 76% (left lateral myocardium) and positive predictive values were up to 85% (left lateral myocardium), whereas sensitivity and positive predictive value dropped to 0-33% (left inferior myocardium).

CONCLUSIONS

Topographic distribution of LGE and histological inflammation seem to influence sensitivity, specificity, positive and negative predictive values. Nevertheless, positive predictive value for LGE of up to 85% indicates that endomyocardial biopsy should be performed "MR-guided". LGE seems to have greater sensitivity than endomyocardial biopsy for the diagnosis of myocarditis.

[MR-guided interventions of the prostate gland: a literature review]

In recent years MR imaging has played an increasingly important role in the diagnosis and treatment of prostate cancer. MR imaging of the prostate allows clear delineation of the anatomic structures and prostate tumors using T 2-weighted images combined with spectroscopy and dynamic examinations. The advantages of MRI make it possible to perform interventions, like biopsies, brachytherapy or different local therapies of the prostate gland. MRI robotic assistance will improve the accuracy of the interventions. Due to the advantages of MR imaging, MR-guided prostate interventions will play a greater role in the future.

Low-dose computed tomography of the paranasal sinus and facial skull using a high-pitch dual-source system--first clinical results

OBJECTIVE

Computed tomography (CT) of the paranasal sinus is the standard diagnostic tool for a wide range of indications in mostly younger patients. This study aims to assess the image quality of CT of the sinus by using a high-pitch dual-source technique with special regard to the radiation dose.

METHODS

Examinations were performed on a second-generation dual-source CT with a pitch factor of 3.0 (dual-source mode). Images were compared with those with a pitch factor of 0.9 on the same system (single-source mode) and with those of 16-slice CT. Image quality was evaluated by four blinded readers using a 5-point scale (1=poor, 5=excellent). Comparison of the dose length product (DLP) was used to estimate radiation exposure.

RESULTS

Seventy-three consecutive patients underwent imaging with the proposed CT protocols. The viewers rated the image quality of the dual-source image sets as nearly as good (3.62) as the single-source images on the same device (4.18) and those on 16-slice CT (3.7). DLP was cut to half of the dose [51 mGycm vs. 97.8 mGycm vs. 116.9 mGycm (p<0.01)].

CONCLUSIONS

Using the proposed dual-source mode when examining the paranasal sinus, diagnostic image quality can be achieved while drastically lowering the patient's radiation exposure.

Different imaging techniques in the head and neck: Assets and drawbacks

In this review, the gold standard imaging techniques for the head and neck and the latest upcoming techniques are presented, by comparing computed tomography (CT), magnetic resonance imaging and positron emission tomography-CT, as well as ultrasound, depending on the examined area. The advantages and disadvantages of each examination protocol are presented. This article illustrates the connection between the imaging technique and the examined area. Therefore, the head and neck area is divided into different sections such as bony structures, nervous system, mucous membranes and squamous epithelium, glandular tissue, and lymphatic tissue and vessels. Finally, the latest techniques in the field of head and neck imaging such as multidetector CT, dual-energy CT, flash CT, magnetic resonance angiography, spectroscopy, and diffusion tensor tractography using 3 tesla magnetic resonance are discussed.

Detection of relevant colonic neoplasms with PET/CT: promising accuracy with minimal CT dose and a standardised PET cut-off

Objective:

To determine the performance of FDG-PET/CT in the detection of relevant colorectal neoplasms (adenomas ≥10 mm, with high-grade dysplasia, cancer) in relation to CT dose and contrast administration and to find a PET cut-off.

Methods:

84 patients, who underwent PET/CT and colonoscopy (n = 79)/sigmoidoscopy (n = 5) for \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\left( {{\hbox{79}} \times {\hbox{6}} + {\hbox{5}} \times {\hbox{2}}} \right)} = {\hbox{484}}$$\end{document} colonic segments, were included in a retrospective study. The accuracy of low-dose PET/CT in detecting mass-positive segments was evaluated by ROC analysis by two blinded independent reviewers relative to contrast-enhanced PET/CT. On a per-lesion basis characteristic PET values were tested as cut-offs.

Results:

Low-dose PET/CT and contrast-enhanced PET/CT provide similar accuracies (area under the curve for the average ROC ratings 0.925 vs. 0.929, respectively). PET demonstrated all carcinomas (n = 23) and 83% (30/36) of relevant adenomas. In all carcinomas and adenomas with high-grade dysplasia (n = 10) the SUV_max was ≥5. This cut-off resulted in a better per-segment sensitivity and negative predictive value (NPV) than the average PET/CT reviews (sensitivity: 89% vs. 82%; NPV: 99% vs. 98%). All other tested cut-offs were inferior to the SUV_max.

Conclusion:

FDG-PET/CT provides promising accuracy for colorectal mass detection. Low dose and lack of iodine contrast in the CT component do not impact the accuracy. The PET cut-off SUV_max ≥ 5 improves the accuracy.

An exploratory pilot study into the association between microcirculatory parameters derived by MRI-based pharmacokinetic analysis and glucose utilization estimated by PET-CT imaging in head and neck cancer

OBJECTIVES

To examine the feasibility of deriving quantitative microcirculatory parameters and to investigate the relationship between vascular and metabolic characteristics of head and neck tumours in vivo, using dynamic contrast-enhanced (DCE) MRI and fluorodeoxyglucose (FDG) PET imaging.

METHODS

Twenty-seven patients with primary squamous cell carcinoma (SCCA) underwent DCE-MRI and combined PET/CT imaging. DCE-MRI data were post-processed by using commercially available software. Transfer constant (K (trans)), extravascular extracellular blood volume (v (e)), transfer constant from the extracellular extravascular space to plasma (k (ep)) and iAUC (initial area under the signal intensity-time curve) were calculated. 3D static PET data were acquired and standardised uptake values (SUV) calculated.

RESULTS

All microcirculatory parameters in tumours were higher than in normal muscle tissue (P ≤ 0.0019). Significant correlations were shown between k (ep) and K (trans) (ρ = 0.77), v (e) and k (ep) (ρ = -0.7), and iAUC and v (e) (ρ = 0.53). Significant correlations were observed for SUV(mean) and v (e) as well as iAUC (ρ = 0.42 and ρ = 0.66, respectively). SUV(max) was significantly correlated with iAUC (ρ = 0.69).

CONCLUSIONS

The demonstrated relationships between vascular and metabolic characteristics of primary SCCA imply a complex interaction between vascular delivery characteristics and tumour metabolism. The lack of correlation between SUV and K (trans)/k (ep) suggests that both diagnostic techniques may provide complementary information.

Initial experience with 18F-fluoroethylcholine PET/CT in staging and monitoring therapy response of advanced renal cell carcinoma

OBJECTIVE

The use of 18F-fluoroethylcholine (FEC) PET/ CT in staging and monitoring therapy response of advanced renal cell carcinoma (RCC) was prospectively analysed.

METHODS

Preliminary results of two patients with metastatic RCC who underwent tumour nephrectomy as well as FEC PET/CT before and 10 weeks after two cycles of tyrosine kinase inhibitor therapy are presented.

RESULTS

All in all, 18 tumour lesions were detected by baseline PET/CT, of which 10 (56%) were positive in FEC PET and 17 (94%) visible on contrast-enhanced computed tomography (ceCT). Mainly, small lung metastases resulted in the lower detection rate of FEC PET compared with ceCT. In follow-up PET/CT of the first case, progressive disease (PD) occurred with increase in tumour diameters of all metastases but non-uniform metabolic response. In the second case, partial response (PR) was achieved with concordant results of PET and CT. These results were confirmed by further CT in the course of disease.

CONCLUSIONS

In this small sample more than half of the RCC metastases were evident in baseline FEC PET. Monitoring therapy, FEC PET showed heterogeneous results in the first case with PD and was consistent with ceCT in the second one displaying PR.