Multi-Energy Low-Kiloelectron Volt versus Single-Energy Low-Kilovolt Images for Endoleak Detection at CT Angiography of the Aorta

Purpose To compare image quality, diagnostic performance, and conspicuity between single-energy and multi-energy images for endoleak detection at CT angiography (CTA) after endovascular aortic repair (EVAR). Materials and Methods In this single-center prospective randomized controlled trial, individuals undergoing CTA after EVAR between August 2020 and May 2022 were allocated to imaging using either low-kilovolt single-energy images (SEI; 80 kV, group A) or low-kiloelectron volt virtual monoenergetic images (VMI) at 40 and 50 keV from multi-energy CT (80/Sn150 kV, group B). Scan protocols were dose matched (volume CT dose index: mean, 4.5 mGy ± 1.8 [SD] vs 4.7 mGy ± 1.3, P = .41). Contrast-to-noise ratio (CNR) was measured. Two expert radiologists established the reference standard for the presence of endoleaks. Detection and conspicuity of endoleaks and subjective image quality were assessed by two different blinded radiologists. Interreader agreement was calculated. Nonparametric statistical tests were used. Results A total of 125 participants (mean age, 76 years ± 8; 103 men) were allocated to groups A (n = 64) and B (n = 61). CNR was significantly lower for 40-keV VMI (mean, 19.1; P = .048) and 50-keV VMI (mean, 16.8; P < .001) as compared with SEI (mean, 22.2). In total, 45 endoleaks were present (A: 23 vs B: 22). Sensitivity for endoleak detection was higher for SEI (82.6%, 19 of 23; P = .88) and 50-keV VMI (81.8%, 18 of 22; P = .90) as compared with 40-keV VMI (77.3%, 17 of 22). Specificity was comparable among groups (SEI: 92.7%, 38 of 41; both VMI energies: 92.3%, 35 of 38; P = .99), with an interreader agreement of 1. Conspicuity of endoleaks was comparable between SEI (median, 2.99) and VMI (both energies: median, 2.87; P = .04). Overall subjective image quality was rated significantly higher for SEI (median, 4 [IQR, 4-4) as compared with 40 and 50 keV (both energies: median, 4 [IQR, 3-4]; P < .001). Conclusion SEI demonstrated higher image quality and comparable diagnostic accuracy as compared with 50-keV VMI for endoleak detection at CTA after EVAR. Keywords: Aneurysms, CT, CT Angiography, Vascular, Aorta, Technology Assessment, Multidetector CT, Abdominal Aortic Aneurysms, Endoleaks, Perigraft Leak Supplemental material is available for this article. © RSNA, 2024.

Long-term patency of arteriovenous fistulas for hemodialysis: A decade's experience in a transplant unit

BACKGROUND

The heterogeneous quality of studies on arteriovenous fistulas outcome, with variable clinical settings and large variations in definitions of patency and failure rates, leads to frequent misinterpretations and overestimation of arteriovenous fistula patency. Hence, this study aimed to provide realistic and clinically relevant long-term arteriovenous fistula outcomes.

METHODS

We retrospectively analyzed all autologous arteriovenous fistulas at our center over a 10-year period (2012-2022). Primary and secondary patency analysis was conducted using the Kaplan-Meier method; multivariate analysis of variance was used to detect outcome predictors. Vascular access-specific endpoints were defined according to the European guidelines on vascular access formation.

FINDINGS

Of 312 arteriovenous fistulas, 57.5% (n = 181) were radio-cephalic (RC_AVF), 35.2% (n = 111) brachio-cephalic (BC_AVF), and 6.3% (n = 20) brachio-basilic (BB_AVF). 6, 12, and 24 months follow-up was available in 290 (92.1%), 282 (89.5%), and 259 (82.2%) patients, respectively. Primary patency rates at 6, 12, and 24 months were 39.5%, 34.8%, and 27.2% for RC_AVF, 58.3%, 44.4%, and 27.8% for BC_AVF, and 40.0%, 42.1%, and 22.2% for BB_AVF (p = 0.15). Secondary patency rates at 6, 12, and 24 months were 65.7%, 63.8%, and 59.0% for RC_AVF, 77.7%, 72.0%, and 59.6% for BC_AVF, and 65.0%, 68.4%, and 61.1% for BB_AVF (p = 0.29). Factors associated with lower primary and secondary patency were hemodialysis at time of arteriovenous fistula formation (p = 0.037 and p = 0.024, respectively) and higher Charlson Comorbidity Index (p = 0.036 and p < 0.001, respectively). Previous kidney transplant showed inferior primary patency (p = 0.005); higher age inferior secondary patency (p < 0.001).

DISCUSSION

Vascular access care remains challenging and salvage interventions are often needed to achieve maturation or maintain patency. Strict adherence to standardized outcome reporting in vascular access surgery paints a more realistic picture of arteriovenous fistula patency and enables reliable intercenter comparison.

Thermal ablation of ultrasound and non-contrast computed tomography invisible primary and secondary liver tumors: targeting by selective intra-arterial lipiodol injection

PURPOSE

To evaluate the technical feasibility and outcomes of thermal ablation following selective intra-arterial lipiodol injection (SIALI) for targeting primary and secondary liver tumors invisible on ultrasound (US) and non-contrast computed tomography (CT).

METHODS

This retrospective study included 18 patients with 20 tumors (67% male, mean age 60.8 ± 12.1 years). The 20 tumors included 15 liver metastases and 5 hepatocellular carcinomas. All patients underwent single-session SIALI and subsequent CT-guided thermal ablation. The primary outcome was a technical success, defined as visualization of the tumor after SIALI and successful thermal ablation. Secondary outcomes were local recurrence rate and procedure-related complications.

RESULTS

The median tumor size was 1.5 (1-2.5) cm. In addition, SIALI was performed with a median volume of 3 (1-10) mL of lipiodol resulting in intra-tumoral iodized oil accumulation in 19 tumors and negative imprint with iodized oil accumulation of the surrounding liver parenchyma in 1 tumor. The technical success rate was 100%. No local occurrence was observed at a mean follow-up time of 3 ± 2.5 years.

CONCLUSION

SIALI to tag liver tumors not visible with US and non-contrast CT before percutaneous ablation is highly feasible and has a high success rate for the treatment of both primary and secondary liver tumors.

Safety and Efficacy of Percutaneous Liver Microwave Ablation Using a Fully Water-Cooled Choke Ring Antenna: First Multicenter Clinical Report

INTRODUCTION

The safety and efficacy of a microwave ablation (MWA) system for the liver with novel technologies in field control, antenna cooling through the inner part of the choke ring, and dual temperature monitoring were evaluated in this multicenter retrospective study.

MATERIAL AND METHODS

Ablation characteristics and efficacy were assessed on follow-up imaging (computed tomography or magnetic resonance imaging). Safety was evaluated according to CTCAE classification.

RESULTS

Eighty-seven liver tumors (65 metastases and 22 hepatocellular carcinomas) measuring 17.8 ± 7.9 mm were treated in 68 patients. Ablation zones measured 35.6 ± 11 mm in longest diameter. The coefficients of variation of the longest and shortest ablation diameters were 30.1% and 26.4%, respectively. The mean sphericity index of the ablation zone was 0.78 ± 0.14. Seventy-one ablations (82%) had a sphericity index above 0.66. At 1 month, all tumors demonstrated complete ablation with margins of 0-5 mm, 5-10 mm, and greater than 10 mm achieved in 22%, 46%, and 31% of tumors, respectively. After a median follow-up of 10 months, local tumor control was achieved in 84.7% of treated tumors after a single ablation and in 86% after one patient received a second ablation. One grade 3 complication (stress ulcer) occurred, but was unrelated to the procedure. Ablation zone size and geometry in this clinical study were in accordance with previously reported in vivo preclinical findings.

CONCLUSION

Promising results were reported for this MWA device. The high spherical index, reproducibility, and predictability of the resulting treatment zones translated to a high percentage of adequate safety margins, providing good local control rate.

Peritransplant Varicosis After Simultaneous Pancreas and Kidney Transplantation Is an Uncommon Cause of Late-Onset and Recurrent Gastrointestinal Bleeding

Ectopic peritransplant varicosis represents an uncommon cause of late-onset gastrointestinal (GI) bleeding after simultaneous pancreas and kidney transplantation (SPK). We report on a 53-year-old female patient who suffered from recurrent upper GI bleeding seven years after SPK with persistent graft function. Upper endoscopy revealed perianastomotic angiodysplasias, treated by clipping and Argon-Plasma-Coagulation. Repeated endoscopy showed no signs of anastomotic ulcer. With persistent symptoms, computed tomography and angiography revealed extensive ectopic varicosis around the pancreas and duodenal graft. With no signs of portal hypertension, pancreas graft venous outflow impairment or arterio-venous fistula, the origin of variceal formation remained unknown. The extended finding did not allow for endovascular treatment by embolization. Surgery with extensive variceal ligation led to persistent cessation of hemorrhage and maintained stable graft function. In patients with unclear recurrent upper GI bleeding after SPK, one should consider ectopic peritransplant varicosis as an exceptional bleeding cause. If endoscopic treatments fail, angiography should be performed to rule out unusual causes of vascular complications. In case of extensive peritransplant varicosis, surgery may remain the only successful therapy, whenever possible including graft preservation in well-functioning grafts.

Electrochemotherapy in radiotherapy-resistant epidural spinal cord compression in metastatic cancer patients

OBJECTIVE

To report efficacy and safety of percutaneous electrochemotherapy (ECT) in patients with radiotherapy-resistant metastatic epidural spinal cord compression (MESCC).

MATERIAL/ METHODS

This retrospective study analyzed all consecutive patients treated with bleomycin-based ECT between February-2020 and September-2022 in a single tertiary referral cancer center. Changes in pain were evaluated with the Numerical Rating Score (NRS), in neurological deficit with the Neurological Deficit Scale, and changes in epidural spinal cord compression were evaluated with the epidural spinal cord compression scale (ESCCS) using an MRI.

RESULTS

Forty consecutive solid tumour patients with previously radiated MESCC and no effective systemic treatment options were eligible. With a median follow-up of 5.1 months [1-19.1], toxicities were temporary acute radicular pain (25%), prolonged radicular hypoesthesia (10%), and paraplegia (7.5%). At 1 month, pain was significantly improved over baseline (median NRS: 1.0 [0-8] versus 7.0 [1.0-10], P < .001) and neurological benefits were considered as marked (28%), moderate (28%), stable (38%), or worse (8%). Three-month follow-up (21 patients) confirmed improved over baseline (median NRS: 2.0 [0-8] versus 6.0 [1.0-10], P < .001) and neurological benefits were considered as marked (38%), moderate (19%), stable (33.5%), and worse (9.5%). One-month post-treatment MRI (35 patients) demonstrated complete response in 46% of patients by ESCCS, partial response in 31%, stable disease in 23%, and no patients with progressive disease. Three-month post-treatment MRI (21 patients) demonstrated complete response in 28.5%, partial response in 38%, stable disease in 24%, and progressive disease in 9.5%.

CONCLUSIONS

This study provides the first evidence that ECT can rescue radiotherapy-resistant MESCC.

CT Angiography of the Aorta Using Photon-counting Detector CT with Reduced Contrast Media Volume

Purpose

To develop and evaluate a low-volume contrast media protocol for thoracoabdominal CT angiography (CTA) with photon-counting detector (PCD) CT.

Materials and Methods

This prospective study included consecutive participants (April-September 2021) who underwent CTA with PCD CT of the thoracoabdominal aorta and previous CTA with energy-integrating detector (EID) CT at equal radiation doses. In PCD CT, virtual monoenergetic images (VMI) were reconstructed in 5-keV intervals from 40 to 60 keV. Attenuation of the aorta, image noise, and contrast-to-noise ratio (CNR) were measured, and subjective image quality was rated by two independent readers. In the first group of participants, the same contrast media protocol was used for both scans. CNR gain in PCD CT compared with EID CT served as the reference for contrast media volume reduction in the second group. Noninferiority analysis was used to test noninferior image quality of the low-volume contrast media protocol with PCD CT.

Results

The study included 100 participants (mean age, 75 years ± 8 [SD]; 83 men). In the first group (n = 40), VMI at 50 keV provided the best trade-off between objective and subjective image quality, achieving 25% higher CNR compared with EID CT. Contrast media volume in the second group (n = 60) was reduced by 25% (52.5 mL). Mean differences in CNR and subjective image quality between EID CT and PCD CT at 50 keV were above the predefined boundaries of noninferiority (-0.54 [95% CI: -1.71, 0.62] and -0.36 [95% CI: -0.41, -0.31], respectively).

Conclusion

CTA of the aorta with PCD CT was associated with higher CNR, which was translated into a low-volume contrast media protocol demonstrating noninferior image quality compared with EID CT at the same radiation dose.Keywords: CT Angiography, CT-Spectral, Vascular, Aorta, Contrast Agents-Intravenous, Technology Assessment© RSNA, 2023See also the commentary by Dundas and Leipsic in this issue.

Surgical therapy of celiac axis and superior mesenteric artery syndrome

INTRODUCTION

Compression syndromes of the celiac artery (CAS) or superior mesenteric artery (SMAS) are rare conditions that are difficult to diagnose; optimal treatment remains complex, and symptoms often persist after surgery. We aim to review the literature on surgical treatment and postoperative outcome in CAS and SMAS syndrome.

METHODS

A systematic literature review of medical literature databases on the surgical treatment of CAS and SMAS syndrome was performed from 2000 to 2022. Articles were included according to PROSPERO guidelines. The primary endpoint was the failure-to-treat rate, defined as persistence of symptoms at first follow-up.

RESULTS

Twenty-three studies on CAS (n = 548) and 11 on SMAS (n = 168) undergoing surgery were included. Failure-to-treat rate was 28% for CAS and 21% for SMAS. Intraoperative blood loss was 95 ml (0-217) and 31 ml (21-50), respectively, and conversion rate was 4% in CAS patients and 0% for SMAS. Major postoperative morbidity was 2% for each group, and mortality was described in 0% of CAS and 0.4% of SMAS patients. Median length of stay was 3 days (1-12) for CAS and 5 days (1-10) for SMAS patients. Consequently, 47% of CAS and 5% of SMAS patients underwent subsequent interventions for persisting symptoms.

CONCLUSION

Failure of surgical treatment was observed in up to every forth patient with a high rate of subsequent interventions. A thorough preoperative work-up with a careful patient selection is of paramount importance. Nevertheless, the surgical procedure was associated with a beneficial risk profile and can be performed minimally invasive.

Coil Embolization of Variant Hepatic Arteries During Percutaneous Arterial Port Catheter Placement for Intraarterial Chemotherapy: Analysis of Intrahepatic Perfusion Redistribution and Treatment Efficacy

PURPOSE

The purpose of this study was to analyze the intrahepatic perfusion redistribution after embolization of hepatic arterial variants during percutaneous arterial port catheter placement as well as to investigate the treatment efficacy of intraarterial chemotherapy in perfusion redistribution-dependent compared to redistribution-independent liver areas.

MATERIALS AND METHODS

This retrospective study included 62 patients (67.7% males, mean age of 56 ± 12 years). A replaced left hepatic artery was encountered in 36/62 (58.1%), a replaced right hepatic artery in 19/62 (30.6%) and a replaced left and right hepatic artery in 7/62 of patients (11.3%), respectively. Subjective perfusion analysis was performed on digital subtracted angiography and computed tomography (CT)/cone-beam computed tomography (CBCT) images evaluating the visibility of the main, segmental and subsegmental branches of the embolized variant hepatic artery, re-perfused from intrahepatic arterial anastomoses. For objective perfusion analysis ROI measurements on CT/CBCT images were taken in the redistribution-dependent and redistribution-independent liver lobe. Response analysis according to RECIST 1.1 was separately calculated for the redistribution-dependent and redistribution-independent liver lobe.

RESULTS

Intrahepatic reperfusion of the embolized variant hepatic artery was observed immediately after embolization with visualization of the subsegmental branches in 95.2% of patients. ROI measurements on CT/CBCT images (right lobe mean 76 ± 30.2 HU, left lobe mean 74.4 ± 30.5, p-value 0.88) did not show any differences. Treatment response after intraarterial chemotherapy did not differ between the redistribution-dependent and redistribution-independent liver lobes.

CONCLUSION

Embolization of hepatic arterial variants during percutaneous arterial port catheter placement results in effective intrahepatic perfusion redistribution and does not compromise treatment efficacy of intraarterial chemotherapy in the redistribution-dependent liver lobe.

Feasibility, safety and efficacy of human intra-tumoral immuno-therapy. Gustave Roussy's initial experience with its first 100 patients

PURPOSE

Many intratumoural (IT) immunotherapies are currently developed in the clinic with the aim of overcoming primary and secondary resistance and/or to limit on-target/off-tumour toxicities of immune checkpoint targeted therapies. This study aimed to describe the feasibility, safety and efficacy of IT immunotherapy treatments.

DESIGN

This retrospective single-centre study included the first 100 consecutive patients enrolled in Gustave Roussy's Human IntraTumoral-ImmunoTherapy (HIT-IT) program. Patient characteristics, target description, image guidance, safety and response according to iRECIST (Response Evaluation Criteria in Solid Tumours for immunotherapy trials) were recorded. Predictive factors of complications and responses were analysed. Survival was also reported.

RESULTS

From 09/2015 to 05/2020, 100 patients had 115 tumours injected during 423 treatment cycles. Most frequent primary tumour arose from the skin (n = 49), digestive track (n = 4) or head and neck (n = 8). Injected tumours' mean diameter was 37 ± 23 mm, and a median number of 4 IT injections per patient (interquartile range:3-5) were performed. Targeted tumours for IT injections were superficial lymph nodes (36.5%), subcutaneous lesions (25.2%), liver tumours (20.9%) and others (17.4% including tumour sites such as deep lymph nodes or lung). Most patients (72%) received systemic immunotherapy in combination with HIT-IT. Procedure- and drug-related adverse events (AEs) occurred in 11.3% and 33.3% of the treatment cycles, respectively. Only 3 procedure-related AEs were grade-3 (0.7%); and no grade-4 or 5 occurred. Among all cycles, 7 grade-3 and 1 grade-5 drug-related AEs were reported. Complete and partial responses were achieved for 5% and 18% of patients, respectively, while stable disease was the best response for 11%. Patients receiving HIT-IT as a 1st-line treatment (24%), or not previously pre-treated with immunotherapy (53%) responded better, p = 0.001 and p = 0.004, respectively. From 1st cycle of IT, 12-month overall progression-free survival and overall survival were 21% (14-31%) and 57% (47-68%), respectively.

CONCLUSIONS

This retrospective study, conducted on patients with cancer and treated within clinical trials at Gustave Roussy, demonstrates the feasibility and safety of the IT immunotherapy strategy.

Single-session transarterial chemoembolization combined with percutaneous thermal ablation in liver metastases 3 cm or larger

PURPOSE

The purpose of this study was to evaluate the safety and efficacy of transarterial chemoembolization (TACE) combined with percutaneous thermal ablation in patients with liver metastases 3 cm in diameter or larger.

MATERIALS AND METHODS

This retrospective study included 39 patients with a total of 46 liver metastases treated. There were 14 men and 25 women, with a mean age of 55 ± 13.3 (SD) (age range: 28-77 years). All patients were treated with a combination of TACE and thermal ablation in a single session. Primary outcome was local tumor progression. Secondary outcomes were procedure related complications and systemic disease progression.

RESULTS

Mean tumor size was 3.6 ± 0.6 (SD) cm (range: 3-5 cm). Conventional TACE was performed in 32 liver metastases (32/46; 70%) and drug-eluting beads-TACE in 14 liver metastases (14/46; 30%) followed by radiofrequency ablation in 34 (34/46; 74%), microwave ablation in 11 (11/46; 24%) and cryoablation in one (1/46; 2%) metastasis. Four grade 2 (4/39; 10%) complications were observed. After a mean follow up of 31.9 ± 26.1 (SD) months (range: 2-113 months) overall local tumor progression rate was 15% (7/46). Local tumor progression rate at 12 months was 13% (6/46). Overall systemic disease progression was seen in 29 patients (29/39; 74%) with a systemic disease progression rate at 12 months of 59% (23/39).

CONCLUSION

Treatment of large liver metastases with TACE and thermal ablation in a single session is safe and achieves high local control rate.

Thermal ablation in the management of oligometastatic colorectal cancer

PURPOSE

To review available evidence on thermal ablation of oligometastatic colorectal cancer.

METHODS

Technical and cancer specific considerations for percutaneous image-guided thermal ablation of oligometastatic colorectal metastases in the liver and lung were reviewed. Ablation outcomes are compared to surgical and radiation therapy literature.

RESULTS

The application of thermal ablation varies widely based on tumor burden, technical expertise, and local cancer triage algorithms. Ablation can be performed in combination or in lieu of other cancer treatments. For surgically non-resectable liver metastases, a randomized trial has demonstrated the superiority of thermal ablation combined with chemotherapy compared to systemic chemotherapy alone in term of progression-free survival and overall survival (OS), with 5-, and 8-year OS of 43.1% and 35.9% in the combined arm vs. 30.3% and 8.9% in the chemotherapy alone arm. As ablation techniques and technology improve, the role of percutaneous thermal ablation may expand even into surgically resectable disease. Many of the prognostic factors for better OS after local treatment of lung metastases are the same for surgery and thermal ablation, including size and number of metastases, disease-free interval, complete resection/ablation, negative carcinoembryonic antigen, neoadjuvant chemotherapy, and controlled extra-pulmonary metastases. When matched for these factors, thermal ablation for lung and liver metastases appears to provide equivalent overall survival as surgery, in the range of 50% at 5 years. Thermal ablation has limitations that should be respected to optimize patient outcomes and minimize complications including targets that are well-visualized by image guidance, measure <3cm in diameter, and be located at least 3mm distance from prominent vasculature or major bronchi.

CONCLUSIONS

The routine incorporation of image-guided thermal ablation into the therapeutic armamentarium for the treatment of oligometastatic colorectal cancer can provide long survival and even cure.

The PEARL Approach for CT-guided Lung Biopsy: Assessment of Complication Rate

Background Percutaneous CT-guided biopsy of lung nodules is an established method with high diagnostic accuracy but a high rate of pneumothorax and chest tube insertion compared with endobronchial methods. Purpose To investigate the effect of a protocol combining patient positioning biopsy-side down, needle removal during expiration, autologous blood patch sealing, rapid rollover, and pleural patching (PEARL) on complication rate after percutaneous CT-guided lung biopsy, especially chest tube insertion. Materials and Methods In a secondary analysis of both prospectively and retrospectively acquired data from December 2019 to November 2020, consecutive participants underwent biopsy with use of the PEARL protocol (prospective data) and were compared with patients who underwent biopsy at the same tertiary cancer center according to the standard method without any additional techniques (controls, retrospective data). Patient demographics, lesion characteristics, intraprocedural data, complications, and histologic results were recorded and compared. Results One hundred patients in the control group (mean age ± standard deviation, 63 years ± 12; 61 men) and 100 participants in the PEARL group (mean age, 64 years ± 12; 48 men) were evaluated. No differences were found in patient and lesion characteristics. The emphysema rate was 47 of 100 patients (47%) in both groups. The rate of pneumothorax was 37 of 100 patients (37%) in the control group versus 16 of 100 (16%) in the PEARL group (P = .001). Of the pneumothoraxes that occurred, fewer were during the intervention in the PEARL group, with 21 of 37 onsets (57%) in the control group versus three of 16 onsets (19%) in the PEARL group (P < .001). A chest tube was inserted in 13 of 100 patients (13%) in the control group and only in one of 100 (1%) in the PEARL group (P = .002). Histologic findings were diagnostic in 94 of 100 patients (94%) in the control group and 95 of 100 (95%) in the PEARL group (P > .99). Conclusion During CT-guided percutaneous lung biopsy, a protocol of positioning biopsy-side down, needle removal during expiration, autologous blood patch sealing, rapid rollover, and pleural patching, or PEARL, reduced rates of pneumothorax and chest tube insertion. © RSNA, 2021.

Prediction of treatment response to transarterial radioembolization of liver metastases: Radiomics analysis of pre-treatment cone-beam CT: A proof of concept study

Purpose

To investigate the potential of texture analysis and machine learning to predict treatment response to transarterial radioembolization (TARE) on pre-interventional cone-beam computed tomography (CBCT) images in patients with liver metastases.

Materials and Methods

In this IRB-approved retrospective single-center study 36 patients with a total of 104 liver metastases (56 % male, mean age 61.1 ± 13 years) underwent CBCT prior to TARE and follow-up imaging 6 months after therapy. Treatment response was evaluated according to RECIST version 1.1 and dichotomized into disease control (partial response/stable disease) versus disease progression (progressive disease). After target lesion segmentation, 104 radiomics features corresponding to seven different feature classes were extracted with the pyRadiomics package. After dimension reduction machine learning classifications were performed on a custom artificial neural network (ANN). Ten-fold cross validation on a previously unseen test data set was performed.

Results

The average administered cumulative activity from TARE was 1.6 Gbq (± 0.5 Gbq). At a mean follow-up of 5.9 ± 0.8 months disease control was achieved in 82 % of metastases. After dimension reduction, 15 of 104 (15 %) texture analysis features remained for further analysis. On a previously unseen set of liver metastases the Multilayer Perceptron ANN yielded a sensitivity of 94.2 %, specificity of 67.7 % and an area-under-the receiver operating characteristics curve of 0.85.

Conclusion

Our study indicates that texture analysis-based machine learning may has potential to predict treatment response to TARE using pre-treatment CBCT images of patients with liver metastases with high accuracy.

Recanalization of Chronic Noncirrhotic, Nonmalignant Splanchnic Thromboses is Feasible: A Transsplenic Assisted Patient-Tailored Approach

The purpose of this study was to evaluate the feasibility of recanalization of chronic noncirrhotic, nonmalignant splanchnic thromboses with a transsplenic assisted patient-tailored approach with or without transjugular intrahepatic portosystemic shunt (TIPS) creation. In this retrospective study, 10 patients (median age, 48.4 years; interquartile range, 5.1 years) underwent revascularization between November 2016 and August 2020. Portal cavernoma was present in all patients, with complete splenic vein thrombosis in 70%. The technical success rate was 80%. Additional TIPS creation was performed in 5 (50%) patients. At a median follow-up of 19.3 months (interquartile range, 17.9 months), the primary and secondary patency rate was 70% and 100%, respectively. During follow-up, 1 patient died due to recurrent upper gastrointestinal variceal hemorrhage. In conclusion, percutaneous transsplenic assisted recanalization of chronic noncirrhotic, nonmalignant splanchnic thromboses is feasible. However, multiple access points may still be needed. Additional TIPS creation appears to be necessary only in case of insufficient portal venous flow into the liver.

Computed Tomography Angiography of the Aorta-Optimization of Automatic Tube Voltage Selection Settings to Reduce Radiation Dose or Contrast Medium in a Prospective Randomized Trial

OBJECTIVES

The aim of this study was to compare the image quality of low-kV protocols with optimized automatic tube voltage selection (ATVS) settings to reduce either radiation dose or contrast medium (CM) with that of a reference protocol for computed tomography angiography (CTA) of the thoracoabdominal aorta.

MATERIALS AND METHODS

In this institutional review board-approved, single-center, prospective randomized controlled trial, 126 patients receiving CTA of the aorta were allocated to one of three computed tomography protocols: (A) reference protocol at 120 kVp and standard weight-adapted CM dose; (B) protocol at 90 kVp, reduced radiation and standard CM dose; and (C) protocol at 90 kVp, standard radiation and reduced CM dose. All three protocols were performed on a third-generation dual-source computed tomography scanner using the semimode of the ATVS system. The image-task-dependent optimization settings of the ATVS (slider level) were adjusted to level 11 (high-contrast task) for protocols A and B and level 3 (low-contrast task) for protocol C. Radiation dose parameters were assessed. The contrast-to-noise ratios (CNRs) of protocols B and C were tested for noninferiority compared with A. Subjective image quality was assessed using a 5-point Likert scale.

RESULTS

Size-specific dose estimate was 34.3% lower for protocol B compared with A (P < 0.0001). Contrast medium was 20.2% lower for protocol C compared with A (P < 0.0001). Mean CNR in B and C was noninferior to protocol A (CNR of 30.2 ± 7, 33.4 ± 6.7, and 30.5 ± 8.9 for protocols A, B, and C, respectively). There was no significant difference in overall subjective image quality among protocols (4.09 ± 0.21, 4.03 ± 0.19, and 4.08 ± 0.17 for protocols A, B, and C, respectively; P = 0.4).

CONCLUSIONS

The slider settings of an ATVS system can be adjusted to optimize either radiation dose or CM at noninferior image quality in low-kV CTA of the aorta. This optimization could be used to extend future ATVS algorithms to take clinical risk factors like kidney function of individual patients into account.

Mitral annular disjunction in patients with severe aortic stenosis: Extent and reproducibility of measurements with computed tomography

•

Mitral annulus disjunction (MAD) is frequent in patients with severe aortic stenosis.

•

Computed tomography enables a highly reproducible assessment of MAD.

•

MAD patients significantly more often have mitral valve prolapse.

Objectives

To determine with CT the prevalence and extent of mitral annular disjunction (MAD) in patients undergoing transcatheter aortic valve replacement (TAVR) and its association with mitral valve disease and arrhythmia.

Methods

We retrospectively evaluated 408 patients (median age, 82 years; 186 females) with severe aortic stenosis undergoing ECG-gated cardiac CT with end-systolic data acquisition. Baseline and follow-up data were collected in the context of a national registry. Two blinded, independent observers evaluated the presence of MAD on multi-planar reformations. Maximum MAD distance (left atrial wall-mitral leaflet junction to left ventricular myocardium) and circumferential extent of MAD were assessed on CT using dedicated post-processing software. Associated mitral valve disease was determined with echocardiography.

Results

7.8 % (32/408) of patients with severe aortic stenosis had MAD. The maximum MAD was 3.5 mm (interquartile range: 3.0–4.0 mm). The circumferential extent of MAD comprised 34 ± 15 % of the posterior and 26 ± 12 % of the entire mitral annulus. Intra- and interobserver agreement for the detection of MAD on CT were excellent (kappa: 0.90 ± 0.02 and 0.92 ± 0.02). Mitral regurgitation (p = 1.00) and severe mitral annular calcification (p = 0.29) were similarly prevalent in MAD and non-MAD patients. Significantly more patients with MAD (6/32; 19 %) had mitral valve prolapse compared to those without (6/376; 2 %; p < 0.001). MAD was not associated with arrhythmia before and after TAVR (p > 0.05).

Conclusions

Using CT, MAD was found in 7.8 % of patients with severe aortic stenosis, with a higher prevalence in patients with mitral valve prolapse. We found no association of MAD with arrhythmia before or after TAVR.

Fusion of Preinterventional MR Imaging With Liver Perfusion CT After RFA of Hepatocellular Carcinoma: Early Quantitative Prediction of Local Recurrence

OBJECTIVES

The aim of this study was to evaluate the ability of fusion of pretreatment magnetic resonance (MR) imaging with posttreatment perfusion-CT (P-CT) after radiofrequency ablation (RFA) of hepatocellular carcinomas (HCCs) and to determine treatment success in an objective, quantitative way.

MATERIALS AND METHODS

In this institutional review board-approved study, 39 patients (78.4% male; mean age 68.2 ± 8.5 years) with a total of 43 HCCs, who underwent RFA at our institution and had diagnostic pre-RFA MR imaging and post-RFA P-CT, were included in the study. Post-RFA P-CT was performed within 24 hours after RFA. In a first step, the pre-RFA MR imaging, depicting the HCC, was registered onto the post-RFA P-CT using nonrigid image registration. After image registration, the MR data were reloaded jointly with the calculated perfusion parameter volumes into the perfusion application for quantitative analysis. A 3-dimensional volume of interest was drawn around the HCC and the ablation zone; both outlines were automatically projected onto all perfusion maps. Resulting perfusion values (normalized peak enhancement [NPE, %]; arterial liver perfusion [ALP, in mL/min/100 mL]; BF [blood flow, mL/100 mL/min]; and blood volume [BV, mL/100 mL]) and histogram data were recorded. Local tumor recurrence was defined in follow-up imaging according to the EASL guidelines.

RESULTS

Image registration of MR imaging and CT data was successful in 37 patients (94.9%). Local tumor recurrence was observed in 5 HCCs (12%). In the local tumor recurrence group (LTR-group), HCC size was significantly larger (22.7 ± 3.9 cm vs 17.8 ± 5.3 cm, P = 0.035) and the ablation zone was significantly smaller (29.8 ± 6.9 cm vs 39.3 ± 6.8 cm, P = 0.014) compared with the no-local tumor recurrence group (no-LTR group). The differences (ablation zone - tumor) of the perfusion parameters NPE, ALP, BF, and BV significantly differed between the 2 groups (all P's < 0.005). Especially, the difference (ablation zone - tumor) of NPE and ALP, with a cutoff value of zero, accurately differentiated between LTR or no-LTR in all cases. A negative difference of these perfusion parameters identified local tumor recurrence in all cases.

CONCLUSIONS

Image registration of pre-RFA MR imaging onto post-RFA P-CT is feasible and allows to predict local tumor recurrence within 24 hours after RFA in an objective, quantitative manner and with excellent accuracy.

Deep learning for automatic quantification of lung abnormalities in COVID-19 patients: First experience and correlation with clinical parameters

RATIONALE AND OBJECTIVES

To demonstrate the first experience of a deep learning-based algorithm for automatic quantification of lung parenchymal abnormalities in chest CT of COVID-19 patients and to correlate quantitative results with clinical and laboratory parameters.

MATERIALS AND METHODS

We retrospectively included 60 consecutive patients (mean age, 61 ± 12 years; 18 females) with proven COVID-19 infection undergoing chest CT between March and May 2020. Clinical and laboratory data (within 24 h before/after chest CT) were recorded. Prototype software using a deep learning algorithm was applied for automatic segmentation and quantification of lung opacities. Percentage of opacity (PO, ground-glass and consolidations) and percentage of high opacity (PHO, consolidations), were defined as 100 times the volume of segmented abnormalities divided by the volume of the lung mask.

RESULTS

Automatic CT analysis of the lung was feasible in all patients (n = 60). The median time to accomplish automatic evaluation was 120 s (IQR: 118-128 s). In four cases (7 %), manual corrections were necessary. Patients with need for mechanical ventilation had a significantly higher PO (median 44 %, IQR: 23-58 % versus 13 %, IQR: 10-24 %; p = 0.001) and PHO (median: 11 %, IQR: 6-21 % versus 3%, IQR: 2-7 %, p = 0.002) compared to those without. The PO and PHO moderately correlated with c-reactive protein (r = 0.49-0.60, both p < 0.001) and leucocyte count (r = 0.30-0.40, both p = 0.05). PO had a negative correlation with SO2 (r=-0.50, p = 0.001).

CONCLUSION

Preliminary experience indicates the feasibility of a rapid, automatic quantification tool of lung parenchymal abnormalities in COVID-19 patients using deep learning, with results correlating with laboratory and clinical parameters.

[Diagnosis and Minimal Invasive Treatment of Benign Prostatic Hyperplasia]

Diagnosis and Minimal Invasive Treatment of Benign Prostatic Hyperplasia Abstract. Benign prostatic hyperplasia (BPH) is a common condition in men aged 50 - 60 years with a prevalence of about 50 %. After failure of conservative treatment, the standard treatment of BPH is transurethral resection of the prostate (TURP). However, over the last years prostatic artery embolization (PAE) emerged as a minimal invasive alternative to treat lower urinary tract symptoms. After patient assessment by MRI and CT of the prostate to rule out possible contraindications of PAE, the procedure can be performed in an outpatient setting under local anesthesia by an interventional radiologist. Especially for frail patients and / or patients with special risks regarding surgery / anesthesia, PAE may be an alternative to TURP with fewer complications.

[Endometriosis]

Endometriosis Abstract. Endometriosis, which is the presence of functional endometrial tissue outside the endometrium, represents one of the most common gynecological diseases. Given the variability of the symptoms depending on the exact localization of the disease, it is not uncommon for a patient to be diagnosed only after approximately 10 years of suffering. Localizations of the disease can include the typical endometrioma of the ovaries and in particular the lesser pelvis (e. g., fallopian tubes, uterine ligaments). It is then termed "deep pelvic endometriosis" and may be the reason for scarring, chronic pelvic pain and infertility. MRI has become increasingly popular in assessing the extent of the disease, due to its increasing availability and excellent soft tissue contrast. Recently, European guidelines have been published to better standardize technical MRI parameters and reporting, in addition to several scoring systems (e. g., the ENZIAN score), which have been established in the past. This allows for a precise localization of the disease and may guide surgical management in advanced cases. Other therapeutic options - depending on the severity of the symptoms - include pain medication or hormonal treatments. In the case of adenomyosis, the embolization of the uterine arteries as a minimally invasive approach has demonstrated excellent results.

Inadequate Perioperative Prophylaxis and Postsurgical Complications After Graft Implantation Are Important Risk Factors for Subsequent Vascular Graft Infections: Prospective Results From the Vascular Graft Infection Cohort Study

BACKGROUND

Reconstructive vascular surgery has become increasingly common. Vascular graft infections (VGIs) are serious complications, leading to increased morbidity and mortality. Previously described risk factors for VGIs include groin incisions, wound infections, and comorbidities. We aimed to identify modifiable predictors for VGIs as targets for infection prevention strategies.

METHODS

Participants of the prospective Vascular Graft Infection Cohort (VASGRA) with surgery between 2013 and 2017 were included. The observation time was calculated from surgery until a confirmed VGI or the last follow-up. Variables were assessed by infection status, using non-parametric tests. Univariable and multivariable Cox proportional hazard regression models, adjusted for demographic factors, were applied to assess risk factors for a VGI.

RESULTS

A total of 438 predominantly male (83.1%) patients with a median age of 71 years (interquartile range [IQR] 63 - 76) contributed to 554 person years of follow-up. Thereof, 39 (8.9%) developed a VGI, amounting to an incidence rate of 7.0/100 person years. We found incisional surgical site infections (adjusted hazard ratio [aHR] 10.09, 95% CI 2.88 - 35.34); hemorrhage (aHR 4.92, 1.28-18.94); renal insufficiency (aHR 4.85, 1.20 - 19.61); inadequate perioperative prophylaxis in patients with an established antibiotic treatment, compared to the additional application of perioperative prophylaxis (aHR 2.87, 95% CI 1.17 - 7.05); and procedure time increases of 1-hour intervals (aHR 1.22, 95% CI 1.08 - 1.39) to be risk factors for VGIs.

CONCLUSIONS

We identified procedure time; inadequate perioperative prophylaxis, especially among patients with an established antibiotic treatment; and several postsurgical infectious and non-infectious complications as modifiable, predictive factors for VGIs and, therefore, as keys to improved surveillance programs and prevention strategies.

CLINICAL TRIALS REGISTRATION

NCT01821664.

MRI of complex regional pain syndrome in the foot

PURPOSE

To evaluate the diagnostic potential of MRI in patients with suspected CRPS (complex regional pain syndrome).

METHOD

A retrospective health-record search was conducted for patients with suspected CRPS (foot). Fifty patients with initially suspected CRPS were included (37 females (51 ± 13 years) and 13 males (44 ± 15 years)). All patients underwent MRI. Two radiologists assessed skin, bone, and soft tissue parameters on MRI. The final diagnosis was CRPS (Gold standard: Budapest criteria) or non-CRPS. MRI parameters were compared between CRPS patients and non-CRPS patients.

RESULTS

CRPS was diagnosed in 22/50(44 %) patients. Skin thickness (1.9 ± 0.5 mm vs. 1.7 ± 0.3 mm, p = 0.399), enhancement, and subcutaneous edema showed no differences between CRPS and non-CRPS patients. Bone marrow edema presence and pattern were not different between groups. Up to 50 % of CRPS patients showed no bone marrow edema. Subcortical enhancement and periosteal enhancement were not different between groups. For reader 1, muscle edema score was higher in the non-CRPS group compared to the CRPS group (0.1 ± 0.2 vs. 0.6 ± 1.0, p = 0.008), but not different for reader 2 (0.1 ± 0.5 vs. 0.2 ± 0.8, p = 0.819). Perfusion pattern was more extensive in non-CRPS patients for reader 1 (p = 0.048), but not for reader 2 (p = 0.157). Joint effusions showed no difference between groups.

CONCLUSIONS

MRI cannot distinguish between CRPS and non-CRPS patients. The role of MR imaging in patients with suspected CRPS is to exclude alternative diagnoses that would better explain patients' symptoms.

[Isolated iliac artery aneurysms : Interventional treatment]

CLINICAL ISSUE

Isolated iliac artery aneurysms occur considerably less often than abdominal aortic aneurysms. Mainly older men are affected by this disease. Most of these aneurysms are asymptomatic and are incidentally detected during cross-sectional imaging. Iliac aneurysms with a diameter larger than 3 cm are at risk for rupture, which is associated with high morbidity and mortality.

STANDARD TREATMENT

To prevent their rupture as well as for symptomatic or ruptured aneurysms, endovascular treatment has recently been established as the primary approach due to the decreased morbidity and mortality compared to open repair. Endovascular aneurysm exclusion is performed with stent grafts, and depending on the anatomy, by adjunctive internal iliac artery embolization.

TREATMENT INNOVATIONS

Up to a quarter of treated patients will require additional endovascular revisions during the long term. Reliable imaging follow-up likely increases the safety of elective or emergent endovascular iliac artery aneurysm repair.

Development of an anthropomorphic spine phantom suitable for fusion of MR neurography with interventional flat-panel CT

PURPOSE

To design a spine phantom suitable for fusion of MR neurography (MRN) with interventional flat panel computed tomography (FPCT) images from tissue-equivalent agarose gels and artificial nerves in MRI, including material with equal attenuation to bone in computed tomography (CT).

METHODS

T1-/T2-relaxation times of target tissue were determined in vivo (n = 5) using MR mapping-techniques. Serial dilution of castor oil lipogels was performed ex vivo in order to define correct composition for tissue-equivalent relaxation times. Similarly, serial dilution series of calcium carbonate (CaCO₃) and barium sulphate (BaSO₄) in synthetic resin were used to adjust radiodensity of selected vertebral bodies (L1-L5) and sacrum in CT. Nerve tissue was simulated with agarose-impregnated polyethylene fibers. Spine phantom was assembled using respective components in anthropomorphic geometry. A fat-saturated, T2-weighted 3D SPACE STIR sequence was acquired for MRN and subsequently fused with an on-site FPCT scan of the phantom.

RESULTS

In vivo T1-/T2-values for fat tissue were found to be at 394 ± 16 ms and 161 ± 16 ms, corresponding to a castor oil concentration of 50%. Analogously, bone marrow-equivalent values were measured at 822 ± 21 ms and 67 ± 6 ms, simulated with 40% castor oil. Cortical bone-like radiodensity of 1'115 ± 80 HU was achieved for artificial bone with 30% CaCO₃ and 1.5% BaSO₄. Simulated nerves were successfully depicted in MRN and fused with FPCT, combining optimal contrasts for nerves and bones on-site.

CONCLUSIONS

The customized phantom showed analogous tissue contrasts to in vivo conditions in both MRN and FPCT, facilitating simulations of fusion-image guided spine interventions.

Primary Endovascular Elective Repair and Repair of Ruptured Isolated Iliac Artery Aneurysms Is Durable-Results of 72 Consecutive Patients

PURPOSE

To evaluate outcome of endovascular elective repair and repair of ruptured isolated iliac artery aneurysms (IIAAs) as a primary treatment strategy.

MATERIALS AND METHODS

All patients with an IIAA undergoing endovascular treatment were included. Aneurysms were classified according to an anatomic classification and treated with coiling of the internal iliac artery, stent graft placement in the common to external iliac artery, or placement of a bifurcated aortoiliac stent graft. Between November 1996 and November 2015, 72 patients with 85 IIAAs underwent endovascular repair. Mean age was 73.9 years ± 9.2. Common iliac artery was involved in 63 patients (74.1%), internal iliac artery was involved in 21 patients (24.7%), and external iliac artery was involved in 1 patient (1.2%). Mean diameter was 5 cm (range, 2.5-11 cm). Emergency repair was performed in 19 patients owing to rupture (26.4%).

RESULTS

Overall primary technical success rate was 95.8% with conversion rate to open surgery of 4.2% (all in the emergency group) and in-hospital mortality rate of 1.4%. During mean follow-up of 4.3 years ± 3.3 (median 3.8 y; range, 0-14.2 y), 17 endoleaks were observed (6 type I, 10 type II, 1 type IIIa). Overall reintervention rate was 16.7%. Primary patency rate was 98.6%. During the follow-up period, 22 deaths occurred (30.6%), including 2 aneurysm-related deaths (2.8%).

CONCLUSIONS

Primary endovascular repair of IIAAs shows excellent results and should be considered as first-line therapy. Surgical backup should be available in emergency cases.

Safety of percutaneous axillary artery access with a suture-mediated closing device for parallel endograft aortic procedures – a retrospective pilot study

Abstract. Background: The aim of this study was to evaluate the technical success of percutaneous ultrasound-guided access to the infraclavicular axillary artery with a suture-mediated closing device for patients requiring large-sized upper extremity access. Patients and methods: In 18 consecutive patients (17 male, one female, mean age 73.5 ± 9.6 years, range 52–88 years), artery accesses with the preclosing modification for chimney endografts was gained with 20 ultrasound-guided infraclavicular axillary. Retrospectively, the following endpoints were analysed: technical success of percutaneous ultrasound-guided puncture of the infraclavicular axillary artery as well as introduction and deployment, primary successful haemostasis by preclosing, bailout procedures, overall complication rate including local vascular, cerebrovascular, and peripheral neurological complications. Results: Ultrasound-guided puncture and preclosing procedure was successful in all patients. Mean sheath size was 9.4 ± 1.6 French. Ultrasound-guided puncture as well as introduction and deployment were successful in all patients (100 %). Primary successful haemostasis by preclosing was 70 % (14/20). Postclosing with one or two devices enabled successful haemostasis in another 15 %. Bailout stent graft implantation was necessary in three accesses (15 %), either by transfemoral (n = 2) or transbrachial (n = 1) route. Overall complication rate was 16.5 %, all of them were minor haematomas. Conclusions: Percutaneous ultrasound-guided infraclavicular axillary artery access with preclosing modification seems feasible and safe. The access related complication rate is low and complications can potentially be managed by endovascular means.

Microflora of two different types of poultry litter

1. The microbiological composition of litter (straw and wood shavings) was sampled, prior to placing 1-d-old chicks, during housing of the birds and after depopulation. Two independent trials were conducted. 2. The total aerobic plate count (APC) was determined and the predominant microflora of the samples was identified using flow charts. 3. Before chick placement, the APC of wood shavings (about 4.0 log/g) was lower than the APC of straw (about log 7.5/g). With stocking, in both types of litter the APC increased to about log 9.76/g straw-litter and log 9.89/g wood shavings, respectively. After depopulation, the APC remained high (> log 9 in both types of litter) within the period of observation. 4. From both experiments, 1981 isolates were collected and identified, most of them were Gram-positive. During stocking the birds, the number of Gram-positive isolates (in particular Gram-positive irregular rods and Micrococcaceae) increased; after depopulation it stayed at that high value, whereas the number of Gram-negative isolates remained low. In both types of litter the isolates were obtained in a comparable proportion.

Comparison of two different meat inspection techniques

Field studies of meat inspection procedures in three different slaughter houses were performed in Germany, in 1996. In total 22,634 fattening pigs from 63 farms were inspected twice, using a visual and the traditional (mandatory inspection system) procedure. Statistical analysis was performed using the rate of ND+ (Non-Detected Positives) for both visual and traditional inspection. Neither the visual nor the traditional methods detected all lesions which were supposed to be in the lot of animals inspected. Some of the results could be explained by the nature and obviousness of the respective lesion. Conclusions regarding the future performance of inspection should not be drawn before a formal risk analysis procedure for the particular lesion has been done.

[Furazolidone resistance of E. coli from chicken intestines after prophylactic treatment with bioptivet GB in animal feed]

This study describes the influence of bioptivet GB on minimum inhibitory concentrations (MIC) for furazolidone of the intestinal E. coli flora of young broiler chickens after prophylactic treatment. From day 6 until day 15 one group of 50 birds received a diet containing 326 ppm furazolidone, another group of 75 birds served as non medicated control. Investigated E. coli had been isolated from cloacal swabs and from caecal contents. MIC of 1581 E. coli strains were determined by agar dilution test. MIC of furazolidone for the investigated strains ranged from 2 micrograms/ml to 64 micrograms/ml. For classification as "resistant" or "susceptible" limits of 16 micrograms/ml and 8 micrograms/ml respectively were used. Strains obtained from undosed birds mainly had MIC values of 4 micrograms/ml or 8 micrograms/ml, i.e. two or three times higher than MIC of E. coli ATCC 25 922, MIC values of 16 micrograms/ml or more were recorded only among isolates obtained from chickens which had received the drug. Administration of bioptivet GB resulted in a statistically significant increase in the average MIC. Statistically higher average MIC were recorded among isolates from cloacal swabs only during application of the drug. For strains from caecal contents, the effect became obvious only at the end of the experiment.

Minimum inhibitory concentrations of intestinal Escherichia coli from broiler chickens after oral administration of apramycin

This study describes the influence of apramycin on minimum inhibitory concentrations (MIC) of intestinal Escherichia coli in young broiler chickens, after oral administration of the antibiotic at a dosage equivalent to a prophylactic course of treatment for 10 d. The bacteria were isolated from cloacal swabs and caecal contents. MICs were determined by agar dilution procedures. MIC of apramycin for the investigated strains ranged from 1 microgram ml-1 to 16 micrograms ml-1. Strains obtained from undosed birds mainly had MIC values of 2 micrograms ml-1. MIC values of 8 micrograms ml-1 or more were recorded only among isolates obtained from chickens which had received apramycin. Administration of apramycin resulted in a slight but statistically significant increase in the average MIC. Statistically higher average MICs were recorded among isolates from cloacal swabs 10 d after withdrawal until the end of the experiment. For strains from caecal contents, this was demonstrated only on one sampling occasion, 15 d after withdrawal.

[Resistance to tetracycline of E. coli of chicken intestines after prophylactic treatment of animal feed with bioptivet GB]

This study describes the influence of bioptivet GB on minimum inhibitory concentrations (MIC) for oxytetracycline (OTC) of the intestinal E. coli flora of young broiler chickens after oral administration at a dosage equivalent to a prophylactic course of treatment. From day 6 until day 15 one group of 50 birds received a diet containing 124 ppm OTC, another group of 75 birds served as non medicated control. Investigated E. coli had been isolated from cloacal swabs and from caecal contents. MIC of 1581 E. coli strains were determined by agar dilution test procedures. MIC of OTC for the investigated strains were either > or = 128 micrograms/ml (resistant) or < or = 4 micrograms/ml (susceptible). Even from undosed birds resistant strains were isolated frequently, especially from samples of caecal contents. Administration of bioptivet GB resulted in a statistically significant increase in the average MIC. Statistically higher average MIC were recorded among isolates from cloacal swabs only during application of the drug. For strains from caecal contents this could be demonstrated until the end of the experiment.

Aspartate aminotransferase isozymes in Panicum miliaceum L., an NAD-malic enzyme-type C4 plant: comparison of enzymatic properties primary structures, and expression patterns

Panicum miliaceum has at least three isozymes of aspartate aminotransferase (AspAT); the cytosolic and mitochondrial isozymes (cAspAT and mAspAT) are major components and the third is a minor isozyme. Fractionation of leaf subcellular components showed that the minor isozyme was localized in plastids (pAspAT). We purified the three isozymes from green leaves of P. miliaceum. Both cAspAT and pAspAT consisted of triple subforms having the same molecular size but different isoelectric points. No substantial difference in enzymatic properties was observed among these isozymes besides the pH profiles. We isolated a full-length cDNA clone for pAspAT. This clone contains an open reading frame that encodes 457 amino acids. The amino-terminal region of the pAspAT precursor shares common features of plastid transit peptides. The amino acid sequence of P. miliaceum pAspAT shows higher similarity with other plant pAspATs than P. miliaceum cAspAT and mAspAT. The mRNA levels of the three isozymes were high in leaves compared with roots and mesocotyls. The three isozymes showed different expression patterns against environmental stimuli such as light and nitrate. The activities and protein levels of cAspAT and mAspAT increased during greening in accordance with those of phosphoenolpyruvate carboxylase and NAD-malic enzyme involved in the C4 pathway, primarily as a consequence of the increase in the levels of their mRNAs. By contrast, pAspAT was constitutively expressed during greening. The activity and protein levels of cAspAT and mAspAT selectively increased during recovery from an nitrogen deficit, primarily as a consequence of increase in the levels of their mRNAs while those of pAspAT remained unchanged.

Converting tissue plasminogen activator to a zymogen: a regulatory triad of Asp-His-Ser

Unlike most serine proteases of the chymotrypsin family, tissue-type plasminogen activator (tPA) is secreted from cells as an active, single-chain enzyme with a catalytic efficiency only slightly lower than that of the proteolytically cleaved form. A zymogenic mutant of tPA has been engineered that displays a reduction in catalytic efficiency by a factor of 141 in the single-chain form while retaining full activity in the cleaved form. The residues introduced in the mutant, serine 292 and histidine 305, are proposed to form a hydrogen-bonded network with aspartate 477, similar to the aspartate 194-histidine 40-serine 32 network found to stabilize the zymogen chymotrypsinogen.

Ratification of broiler carcase condemnations in poultry meat inspection

1. In the years 1985 to 1989 decisions (approvals and condemnations) made by poultry meat inspectors were examined by the individual reinspection of 26,815 broiler carcases. 2. The extent of agreement between inspection and revision ranged between 83.2 and 86.2%. 3. Agreement between inspectors and revisors was higher for the category of approved birds than for the condemned category. 4. Differences in the criteria used to assess the birds were observed. 5. The conclusion was drawn that findings in meat inspection require further discussion to reach an agreed standard.

[Clinical evaluation of S6472 (prolonged action preparation of cefaclor) in the treatment of skin and soft tissue infections. A double blind comparison of S6472 and cefaclor]

A double-blind comparative study of S6472 and cefaclor (CCL) was conducted to evaluate the therapeutic efficacy, safety and usefulness in the treatment of skin and soft tissue infections. Either 750 mg b.i.d. of S6472 or 750 mg t.i.d. of CCL was administered orally to patients for a period of 7 consecutive days. Of the 250 cases (123 cases of S6472 group and 127 cases of CCL group) recruited in this trial, 228 cases (114 cases of S6472 and 114 cases of CCL) were adopted by the committee members for the evaluation of therapeutic efficacy, 238 cases (118 cases of S6472 group and 120 cases of CCL group) for usefulness, and 245 cases (121 cases of S6472 group and 124 cases of CCL group) were adopted for the evaluation of side effects. The backgrounds of both patients group were almost similar. The results obtained were as follows: Overall clinical effectiveness Of the 114 patients treated with S6472, excellent clinical responses were obtained in 11 patients, good in 79, fair in 19, poor in 5 (efficacy rate 78.9%), and of the 114 patients treated with CCL, excellent were in 16, good in 78, fair in 13, poor in 7 (efficacy rate 82.5%). There was no statistically significant difference between the 2 groups. Clinical effectiveness classified by initial severity and bacteriological efficacy There was no significant difference between the 2 groups in the clinical effectiveness classified by initial severity and in the bacteriological efficacy. Side effects were noticed in 5 patients of 121 treated with S6472 (4.1%) and in 2 patients of 124 treated with CCL (1.6%), and other 13 patients developed some abnormal laboratory findings. But these undesirable reactions were mild, and developed no significant difference between the 2 groups in the incidence of side effects. There was no significant difference between the 2 groups in the usefulness of the drugs. Conclusively, 750 mg b.i.d. of S6472 is anticipative of the same clinical efficacy, safety and usefulness as compared with that of 750 mg t.i.d. of CCL in the treatment of skin and soft tissue infections.

[Fundamental and clinical studies of a sustained release preparation of cefaclor in the surgical field]

Fundamental and clinical studies of S6472 (sustained release preparation of cefaclor (CCL] were conducted in the surgical field and it was confirmed that the preparation is a useful drug. The following is the summary of the results from the fundamental and clinical studies: In vitro antibacterial activity. CCL showed MICs of 0.78 to 6.25 micrograms/ml against almost strains of S. aureus, E. coli and Klebsiella isolated from surgical wound regions, and the antibacterial activities were stronger than those of cephalexin (CEX). Clinical efficacy. S6472 was orally administered to 33 patients with skin and soft tissue infections in 2 divided doses. As a result, excellent clinical response was observed in 13 patients, good response observed in 14 patients, fair in 4 and poor in 1. The clinical efficacy in 1 of the 33 patients was unknown. Overall clinical effective rate was 84.4%. Adverse reaction. In 2 patients, mild gastrointestinal symptoms were observed.