Percutaneous endobiliary ablation of malignant biliary strictures with a novel temperature-controlled radiofrequency ablation device

PURPOSEWe aimed to determine the safety and effectiveness of percutaneous endobiliary radiofrequency ablation of malignant biliary obstructions with a temperature-controlled radiofrequency ablation device.METHODSIn this single center retrospective study, a total of 62 consecutive patients with malignant biliary obstruction were evaluated. Thirty patients who underwent endobiliary radiofrequency ablation with metallic stent placement were in the study group and 32 patients who underwent only metallic stenting were in the control group. Outcomes of this study were technical success, complications related to the procedure, stent patency, and overall survival.RESULTSAll procedures were technically successful in both groups. There was no procedure-related mortality in either group. Procedural complication rates were similar between the groups. Although statistically not significant, the only two major complications (hemobilia requiring endovascular treatment) were in the control group. Median primary stent patency was significantly longer in the study group than in the control group (223 days vs. 158 days; P = 0.016). Median survival rates were also longer in the study group (246 days vs. 198 days; P = 0.004).CONCLUSIONPercutaneous endobiliary radiofrequency ablation is safe and feasible with this novel radiofrequency ablation device in patients with malignant biliary obstruction. Percutaneous endobiliary radiofrequency ablation has a potential to improve both stent patency and survival

Radiation doses from head, neck, chest and abdominal CT examinations: an institutional dose report

PURPOSEWe aimed to obtain typical values for head, neck, chest, and abdominal computed tomography (CT) examinations from routine patients in 2018, and to review our data with national and international diagnostic reference levels (DRLs).METHODSSingle-phase head, neck, chest, and abdominal CT scans of adults performed in 64-slice CT in 2018 were included in this study. Radiation dose parameters of CT scans were obtained from the picture archiving and communication system of our hospital. Volumetric CT dose index (CTDIvol) and dose length product (DLP) values were recorded. Effective dose (ED) and scan length was calculated. A 16 cm diameter phantom is referenced for head CT, and 32 cm diameter phantom is referenced for neck, chest, and abdominal CT. Descriptive statistics of the variables were given according to the normality testing.RESULTSMedian CTDIvol value was 53 mGy for the head, 13.1 mGy for the neck, 8.3 mGy for the chest, and 8.6 mGy for the abdomen. Median DLP value was 988 mGy.cm for the head, 299 mGy.cm for the neck, 314 mGy.cm for the chest, and 457 mGy.cm for the abdomen. Median ED value was 2.07 mSv for the head, 1.76 mSv for the neck, 4.4 mSv for the chest, and 6.8 mSv for the abdomen. Considering national DRLs, median CTDIvol values of head, chest, and abdomen were lower, whereas median DLP and ED values of head and chest were higher. For the abdomen, the median DLP and ED values were lower.CONCLUSIONOverall radiation dose parameters obtained in this study points out the need for optimization of head CT examinations in our institution

Pediatrik Hastalarda Yüksek Pitch Kullanılarak Bilgisayarlı Tomografi Çekilmesinin Radyasyon Dozu Üzerine Etkisi

High pitch Computed Tomography effect on radiation dose in pediatric patients, Hacettepe University Faculty of Medicine, Thesis in Radiology, Ankara, 2013. The aim of this study is to assess radiation dose reduction and image quality with high-pitch dual source CT in comparison with standard pitch with pediatric thorax and abdominal CT. Between Janunary 2012 and June 2013, a total of 192 patients (median age 65,2 months) underwent high pitch thorax CT and 142 patients (median age 52 months) underwent high pitch abdominal CT in this study. High-pitch (value:3) mode CT was performed with 64-slice DSCT. This was compared to a group of 57 patients (median age 74,6 months) who underwent standard thorax CT (pitch: <1.5) and a group of 54 patients (median age 54,2 months) who underwent standard abdominal CT (pitch: <1.5). Scanning protocols were adjusted for clinical indication and patient weight in both groups. At aortic valve in thorax and at the umbilical level in abdomen anteroposterior (APD) and lateral (LD) diameters was measured in all patients and effective diameter (ED) was calculated. Scan time (ST) and length (SL), qualitative (subjective noise, diagnostic confidence and artifacts related to patient, respiratory,cardiac or bowel movement) and quantitative (density measurements from: descending aorta, muscles around shoulder and outside of thorax in thorax; liver, abdominal aorta, psoas muscle and outside of abdominal wall in abdomen) assessment, CTDIvol, DLP, size specific dose estimate (SSDE, calculated by using conversion factors given by AAPM at report no: 204) were assessed in both groups. Comparisons were made by using chi-square test, independent sample t test and Mann-Whitney U test. Both patient groups at thorax CT were similar with respect to age, APD, LD and ED. Mean ST of high-pitch thorax CT was 1.19 s, while it was 7,09 s in standard pitch mode CT. In comparison with standard pitch mode, high pitch mode of DSCT reduced radiation exposure by 50% (SSDE according to ED 1,94 and 4,16 mGy). CTDlvol, DLP and SSDE parameters were significantly lower in high pitch mode (p<0.001). Subjective noise on high pitch thoracic imaging did not have any effect on diagnostic confidence and quantitative measures were similar among both types of imaging. Less artifacts, either related to patient movement, cardiac or respiratory were observed with high pitch imaging (p<0.001). Both patient groups at abdominal CT were similar with respect to age, APD, LD, ED and SL. Mean ST of high-pitch abdominal CT was 1.59 s, while it was 10,9 s in standard pitch mode CT. In comparison with standard pitch mode, high pitch mode of DSCT reduced radiation exposure by 60% (size specific dose estimatation according to ED 1,86 and 4,74 mGy). CTDlvol, DLP and SSDE parameters were significantly lower in high pitch mode (p<0.001). Subjective noise on high pitch abdominal imaging did not have any effect on diagnostic confidence and quantitative measures were different among both types of imaging. Less artifacts, either related to patient or bowel movement were observed with high pitch imaging (p<0.001). The use of high pitch DSCT at thoracic and abdominal pediatric imaging significantly decreases scan times and radiation exposure when compared to standard CT.Pediatrik hastalarda yüksek pitch kullanılarak Bilgisayarlı Tomografi çekilmesinin radyasyon dozu üzerine etkisi, Hacettepe Tıp Fakültesi Radyoloji Anabilim Dalı Uzmanlık Tezi, Ankara, 2013. Bu çalışmanın amacı çocuk hastalarda yüksek pitch modu ile elde edilmiş toraks ve abdomen BT incelemelerini, standart toraks ve abdomen BT incelemeleri ile radyasyon dozu ve görüntü kalitesi açısından karşılaştırmaktır. Ocak 2012 ile Haziran 2013 tarihleri arasında yüksek pitch modunda elde edilmiş 192 toraks (ortalama yaş 65,2 ay), 142 abdomen (ortalama yaş 52 ay) BT incelemesi çalışma grubunu oluşturmaktadır. Yüksek pitch (pitch:3) modunda BT'ler 64-kesitli Çift Tüplü BT'de gerçekleştirilmiştir. Karşılaştırılmanın yapıldığı standart pitch (<1,5) ile elde edilmiş 57 toraks (ortalama yaş 74,6 ay), 54 abdomen (ortalama yaş 54,2 ay) BT incelemesi kontrol grubunu oluşturmaktadır. Her iki grupta tarama protokolleri klinik endikasyon ve hasta ağırlığına göre ayarlandı. Her iki grupta, toraks incelemelerinde aort kapağı seviyesinden geçen kesitlerden, abdomen incelemelerinde umblikal seviyeden geçen kesitlerden anteroposteriyor (APÇ) ile lateral (LÇ) vücut çapı ölçüldü ve efektif çap (EÇ) hesaplandı. Her iki grupta, tarama süresi (TS) ile uzunluğu (TU), kalitatif (subjektif gürültü, tanısal güvenilirlik ve hasta hareketi, solunum, kalp ya da barsak hareketine bağlı artefaktlar) ve kantitatif ölçümler (toraks tetkiklerinde inen aorta, omuz çevresi kasları ve toraks dışından; abdomen tetkiklerinde karaciğer, abdominal aorta, psoas kası ve abdomen dışından dansite ölçümleri), CTDIvol, DLP, boyuta özgü doz tahminleri (AAPM tarafından 204 no'lu raporda verilen konversiyon katsayıları kullanılarak hesaplandı) belirlendi. Karşılaştırmalar chi-square testi, independent sample t testi and Mann-Whitney U testi kullanılarak yapıldı. Toraks tetkiklerinde her iki grup yaş, APÇ, LÇ, EÇ açısından benzerdi. Yüksek pitch toraks BT'nin TS'si ortalama 1.19 s iken, standart BT'de TS ortalama 7,09 s'di. Standart pitch ile karşılaştırıldığında yüksek pitch Toraks BT'de radyasyon dozu % 50 oranında azaldı (1,94 ve 4,16 mGy, EÇ'ye göre boyuta özgü doz tahmini); yüksek pitch modunda CTDlvol, DLP ve boyuta özgü doz tahminleri anlamlı olarak daha düşük bulundu (p<0.001).Yüksek pitch modunda Toraks BT incelemelerinde subjektif gürültünün tanısal güvenilirlik üzerine herhangibir etkisi olmadı. Toraks BT incelemelerinde kantitatif ölçümler her iki grup arasında benzerdi. Yüksek pitch görüntülemede hastaya, kalp hareketi ya da solunuma bağlı artefakt daha az gözlendi (p<0.001). Abdomen tetkiklerinde her iki grup yaş, APÇ, LÇ, EÇ ve TU açısından benzerdi. Yüksek pitch abdomen BT'nin TS'si ortalama 1.59 s iken, standart pitch modlu BT'de TS ortalama 10,9 s'di. Standart pitch ile karşılaştırıldığında yüksek pitch abdomen BT'de radyasyon dozu % 60 oranında azaldı ( 1,86 ve 4,74 mGy, EÇ'ye göre SSDE); yüksek pitch modunda CTDlvol, DLP ve boyuta özgü doz tahminleri anlamlı olarak daha düşük bulundu (p<0.001). Yüksek pitch abdomen BT'de subjektif gürültünün tanısal güvenilirlik üzerine herhangi bir etkisi olmadı. Kantitatif ölçümler açısından çalışma ve kontrol grubu birbirinden farklıydı. Yüksek pitch modundaki görüntülemede hasta ya da barsak hareketine bağlı artefakt daha az gözlendi (p<0.001). Yüksek pitch toraks ve abdomen BT, standart BT ile karşılaştırıldığında tarama süresini belirgin kısaltmakta ve radyasyon dozunu önemli ölçüde azaltmaktadır

Comparison Of Image Quality And Radiation Dose Between Prospectively Ecg-Triggered And Retrospectively Ecg-Gated Ct Angiography: Establishing Heart Rate Cut-Off Values In First-Generation Dual-Source Ct

Objective: To evaluate radiation dose and image quality of prospectively electrocardiography (ECG)-triggered and retrospectively ECG-gated coronary computed tomography (CT) angiography and to establish cut-off values of heart rates (HRs) for each technique in firstgeneration dual-source CT. Methods: A total of 200 consecutive patients with suspected coronary artery disease were accepted into the study. Patients were selected randomly for each technique (prospective triggering group n=99, mean age 55.85±10.74 and retrospective gating group n=101, mean age 53.38±11.58). Two independent radiologists scored coronary artery segments for image quality using a 5-point scale. Also, attenuation values of each coronary artery segment and dose-length product values were measured. For each technique, cut-off HR values were determined for the best image quality. Results: Mean image quality scores and attenuation values were found to be higher in the prospective triggering group (p<0.05). Mean radiation dose was 73% lower for the prospective triggering group (p<0.01). The cut-off HR values for good image quality scores were ≤67 beats per minute (bpm) and ≤80 bpm for the prospective triggering and retrospective gating groups, respectively (p<0.05). Increased HR (≥68 and ≥81 bpm, respectively) had negative effects on image quality (p<0.05). Conclusion: The prospective ECG triggering technique has better image quality scores than retrospective ECG gating, particularly in patients who have an HR of less than 68 bpm. Also, a 73% radiation dose reduction can be achieved with prospective ECG triggering. In patients with higher heart rates, retrospective ECG gating is recommended