A case of pancreatic cancer with concomitant median arcuate ligament syndrome treated successfully using an allograft arterial transposition

An association of pancreatic cancer and median arcuate ligament syndrome (MALS) is a rare and challenging situation in terms of treatment. A 60-year-old man diagnosed with pancreatic cancer underwent laparotomy. A pancreaticoduodenectomy was planned, but during the resection part of the operation, a celiac artery stenosis was noticed. The patient was diagnosed with MALS causing almost total celiac artery occlusion, with no radiological solution. The patient was re-operated the next day, and an iliac artery allograft was used for aorta-proper hepatic artery reconstruction, concomitant with the total pancreaticoduodenectomy. Preoperative meticulous evaluation of vascular structures of the celiac trunk and its branches is important, especially in pancreatic surgery. A vascular allograft may be a lifesaving alternative when vascular reconstruction is necessary

Evaluation of transient respiratory motion artifact at gadoxetate disodium-enhanced MRI-Influence of different contrast agent application protocols.

PURPOSE:To evaluate transient severe respiratory motion artifacts (TSM) at gadoxetate disodium-enhanced MRI dependent on the mode of contrast agent application. METHODS:200 patients (71f, 129m; mean 51y) were included in this retrospective IRB-approved study. Contrast application protocols (n = 4) differed with regards to injection rate (2ml or 1ml/sec), dose (weight-based or fixed 10ml) and supplemental oxygen administration (yes/no). SNR measurements were performed in the aorta and portal vein. Qualitatively, three readers assessed arterial phase image quality and TSM independently (4- and 5-point scale, respectively). Quantitative and qualitative results were compared (Kruskal-Wallis test, Dunn's multiple comparison test). The influence of different contrast agent application parameters on the occurrence of respiratory motion artifacts was assessed (univariate analysis). Interrater agreement and reliability were calculated (intraclass correlation coefficient, ICC)). RESULTS:Use of a lower contrast injection rate resulted in significantly higher arterial SNR in the aorta and portal vein (p<0.05). TSM was observed in 12% of examinations. Neither injection rate, contrast dose, nor oxygen had a significant influence. Interrater agreement and reliability for evaluation of image quality and respiratory motion were substantial/ almost perfect (ICC = 0.640-0.915). CONCLUSIONS:Technical factors regarding the specific mode of contrast application do not seem to significantly reduce the incidence of severe transient respiratory motion artifacts

The Fusion of MRI and CT in the Planning of Brachytherapy for Cancer of the Uterine Cervix

Introduction: tumors of the uterine cervix are among the most common carcinomas in women. Intracervical brachytherapy is an indispensable part of curative treatment. Although the tumor is significantly more recognizable in MRI than in CT, the practical application of MRI in brachytherapy planning is still difficult. The present study examines the technical possibilities of merging CT and MRI. Materials and Methods: the treatment files and imaging of all 53 patients who had been irradiated by image-guided adaptive brachytherapy (IGABT) between January 2019 and August 2021 at the Department of Radiotherapy of the Hannover Medical School were evaluated, retrospectively. Patients were treated first with an external beam radiotherapy (EBRT) combined with simultaneous chemotherapy. After an average of 4.2 weeks, the preparation for IGABT began. The clinical target volume (CTV) for brachytherapy was contoured first in an MRI acquired before starting EBRT (MRI 1) and once more in a second MRI just before starting IGABT (MRI 2). Then, after inserting the intravaginal applicator, a CT-scan was acquired, and the CTV was contoured in the CT. Finally, the recordings of MRI 1, MRI 2, and the CT were merged, and the congruence of CTVs was quantitatively evaluated. Results: the CTV delineated in MRI 2 was, on average, 28% smaller than that in MRI 1 after an average applied radiation dose of 42 Gy. The CTV delineated in the CT covered an average of no more than 80.8% of the CTV delineated in MRI 2. The congruence of CTVs was not superior in patients with a smit sleeve in the cervical channel, with a 3D-volumetric MRI or with a contrast-enhanced sequence for MRI. Conclusion: the anatomical shape and position of the uterus is significantly changed by introducing a vaginal applicator. Despite the superior delimitability of the tumor in MRI, brachytherapy cannot be reliably planned by the image fusion of an MRI without a vaginal applicator

Experimental Evaluation of the Heat Sink Effect in Hepatic Microwave Ablation.

To demonstrate and quantify the heat sink effect in hepatic microwave ablation (MWA) in a standardized ex vivo model, and to analyze the influence of vessel distance and blood flow on lesion volume and shape.108 ex vivo MWA procedures were performed in freshly harvested pig livers. Antennas were inserted parallel to non-perfused and perfused (700,1400 ml/min) glass tubes (diameter 5mm) at different distances (10, 15, 20mm). Ablation zones (radius, area) were analyzed and compared (Kruskal-Wallis Test, Dunn's multiple comparison Test). Temperature changes adjacent to the tubes were measured throughout the ablation cycle.Maximum temperature decreased significantly with increasing flow and distance (p<0.05). Compared to non-perfused tubes, ablation zones were significantly deformed by perfused tubes within 15 mm distance to the antenna (p<0.05). At a flow rate of 700 ml/min ablation zone radius was reduced to 37.2% and 80.1% at 10 and 15 mm tube distance, respectively; ablation zone area was reduced to 50.5% and 89.7%, respectively.Significant changes of ablation zones were demonstrated in a pig liver model. Considerable heat sink effect was observed within a diameter of 15 mm around simulated vessels, dependent on flow rate. This has to be taken into account when ablating liver lesions close to vessels

Ablation zone geometry after CT-guided hepatic microwave ablation: evaluation of a semi-automatic software and comparison of two different ablation systems

Purpose The aims of this study were to evaluate a semi-automatic segmentation software for assessment of ablation zone geometry in computed tomography (CT)-guided microwave ablation (MWA) of liver tumors and to compare two different MWA systems. Material and Methods 27 patients with 40 hepatic tumors (primary liver tumor n = 20, metastases n = 20) referred for CT-guided MWA were included in this retrospective IRB-approved study. MWA was performed using two systems (system 1: 915 MHz; n = 20; system 2: 2.45 GHz; n = 20). Ablation zone segmentation and ellipticity index calculations were performed using SAFIR (Software Assistant for Interventional Radiology). To validate semi-automatic software calculations, results (2 perpendicular diameters, ellipticity index, volume) were compared with those of manual analysis (intraclass correlation, Pearson’s correlation, Mann–Whitney U test; p < 0.05 deemed significant. Results Manual measurements of mean maximum ablation zone diameters were 43 mm (system 1) and 34 mm (system 2), respectively. Correlations between manual and semi-automatic measurements were r = 0.72 and r = 0.66 (both p < 0.0001) for perpendicular diameters, and r = 0.98 (p < 0.001) for volume. Manual analysis demonstrated that ablation zones created with system 2 had a significantly lower ellipticity index compared to system 1 (mean 1.17 vs. 1.86, p < 0.0001). Results correlated significantly with semi-automatic software measurements (r = 0.71, p < 0.0001). Conclusion Semi-automatic assessment of ablation zone geometry using SAFIR is feasible. Software-assisted evaluation of ablation zones may prove beneficial with complex ablation procedures, especially for less experienced operators. The 2.45 GHz MWA system generated a significantly more spherical ablation zone compared to the 915 MHz system. The choice of a specific MWA system significantly influences ablation zone geometry

Contrast agent application protocols (group 1–4) for acquisition of gadoxetate disodium-enhanced MR images and characteristics of patients included in each group.

<p>Contrast agent application protocols (group 1–4) for acquisition of gadoxetate disodium-enhanced MR images and characteristics of patients included in each group.</p

Mean motion scores in different phases of the contrast dynamic after injection of gadoxetate disodium, comparison of different contrast agent application protocols (#1–4).

<p>Mean motion score as assessed on a 5-point scale by three readers, in the pre-contrast (pre), arterial (art), portalvenous (pv) and delayed (del) phase, respectively.</p

27 year old male patient with diagnosis of primary sclerosing cholangitis.

<p>Gadoxetate disodium-enhanced liver MRI in the arterial (A) and portalvenous phase (B). Self-limiting severe transient motion can be appreciated in the arterial phase, causing significant degradation of image quality, which is resolved in the portalvenous phase.</p

Arterial phase SNR in the aorta (left) and in the portal vein (right), comparison of different contrast agent application protocols (#1–4).

<p>SNR in the aorta and portal vein were significantly higher in protocol groups using the slower injection rate of 1 ml/sec, as compared to an injection rate of 2 ml/sec (p<0.0001 and p = 0.0016). * indicates a statistical significance.</p