Barton F. Lane

ACR appropriateness Criteria® first trimester bleeding.

Vaginal bleeding is not uncommon in the first trimester of pregnancy. Ultrasound is the foremost modality for evaluating normal development of the gestational sac and embryo and for discriminating the causes of bleeding. While correlation with quantitative βHCG and clinical presentation is essential, sonographic criteria permit diagnosis of failed pregnancies, ectopic pregnancy, gestational trophoblastic disease and spontaneous abortion. The American College of Radiology Appropriateness Criteria guidelines have been updated to incorporate recent data. A failed pregnancy may be diagnosed when there is absence of cardiac activity in an embryo exceeding 7 mm in crown rump length or absence of an embryo when the mean sac diameter exceeds 25 mm. In a stable patient with no intrauterine pregnancy and normal adnexae, close monitoring is advised. The diagnosis of ectopic pregnancy should be based on positive findings rather than on the absence of an intrauterine sac above a threshold level of βHCG. Following abortion, ultrasound can discriminate retained products of conception from clot and arteriovenous fistulae. The American College of Radiology Appropriateness Criteria® are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Imaging of endometrial pathology.

The normal endometrium changes regularly with the menstrual cycle and atrophies after menopause. It is important to be aware of the normal spectrum of endometrial appearances at imaging to accurately detect and diagnose pathologic conditions. This article reviews imaging features of the normal and abnormal endometrium, and conditions which may mimic endometrial pathology. Emphasis will be on ultrasound with sonohysterography and magnetic resonance imaging as these are the imaging modalities of choice for evaluation of the endometrium. The complementary role of hysterosalpingography, computed tomography, and 18-fluorodeoxyglucose-positron emission tomography will also be discussed.

Individually optimized contrast-enhanced 4D-CT for radiotherapy simulation in pancreatic ductal adenocarcinoma.

PURPOSE To develop an individually optimized contrast-enhanced (CE) 4D-computed tomography (CT) for radiotherapy simulation in pancreatic ductal adenocarcinomas (PDA). METHODS Ten PDA patients were enrolled. Each underwent three CT scans: a 4D-CT immediately following a CE 3D-CT and an individually optimized CE 4D-CT using test injection. Three physicians contoured the tumor and pancreatic tissues. Image quality scores, tumor volume, motion, tumor-to-pancreas contrast, and contrast-to-noise ratio (CNR) were compared in the three CTs. Interobserver variations were also evaluated in contouring the tumor using simultaneous truth and performance level estimation. RESULTS Average image quality scores for CE 3D-CT and CE 4D-CT were comparable (4.0 and 3.8, respectively; P = 0.082), and both were significantly better than that for 4D-CT (2.6, P < 0.001). Tumor-to-pancreas contrast results were comparable in CE 3D-CT and CE 4D-CT (15.5 and 16.7 Hounsfield units (HU), respectively; P = 0.21), and the latter was significantly higher than in 4D-CT (9.2 HU, P = 0.001). Image noise in CE 3D-CT (12.5 HU) was significantly lower than in CE 4D-CT (22.1 HU, P = 0.013) and 4D-CT (19.4 HU, P = 0.009). CNRs were comparable in CE 3D-CT and CE 4D-CT (1.4 and 0.8, respectively; P = 0.42), and both were significantly better in 4D-CT (0.6, P = 0.008 and 0.014). Mean tumor volumes were significantly smaller in CE 3D-CT (29.8 cm3, P = 0.03) and CE 4D-CT (22.8 cm3, P = 0.01) than in 4D-CT (42.0 cm3). Mean tumor motion was comparable in 4D-CT and CE 4D-CT (7.2 and 6.2 mm, P = 0.17). Interobserver variations were comparable in CE 3D-CT and CE 4D-CT (Jaccard index 66.0% and 61.9%, respectively) and were worse for 4D-CT (55.6%) than CE 3D-CT. CONCLUSIONS CE 4D-CT demonstrated characteristics comparable to CE 3D-CT, with high potential for simultaneously delineating the tumor and quantifying tumor motion with a single scan.

Postoperative Elevated Resistive Indices Do Not Predict Hepatic Artery Thrombosis in Extended Criteria Donor Livers

Abstract Postoperative transplant liver ultrasounds were analyzed in standard criteria donor (SCD), extended criteria donor (ECD), and donation after cardiac death (DCD) liver allografts to determine if elevated resistive indices (RIs) are consistently present and if they are pathological. Postoperative transplant liver ultrasounds were reviewed from 115 consecutive patients. Hepatic arterial RIs were stratified based on the type of donor: DCD, macrosteatosis (>30%), or standard criteria. In all patients with elevated RI, subsequent ultrasounds were reviewed to demonstrate RI normalization. The mean RI for all 115 patients was 0.64, DCD was 0.67, macrosteatosis was 0.81, and SCD was 0.61 (p = 0.033). The RI on subsequent liver ultrasounds for DCD and macrosteatosis normalized without any intervention. There were no incidences of early hepatic artery thrombosis (HAT) observed in the cohort. Hepatic arterial RI in ECDs and DCDs are elevated in the immediate postoperative period but are not predictive of HAT. It represents interparenchymal graft stiffness and overall graft edema rather than an impending technical complication. The results of our study do not support the routine use of anticoagulation or routine investigation with computed tomography angiography for elevated RIs as these findings are self‐limiting and normalize over a short period of time. We hope that this information helps guide the clinical management of liver transplant patients from expanded criteria donors.

TH-EF-BRA-04: Individually Optimized Contrast-Enhanced 4D-CT for Radiotherapy Simulation in Pancreatic Ductal Adenocarcinoma

PURPOSE To develop an individually optimized contrast-enhanced (CE) 4D-CT for radiotherapy simulation in pancreatic ductal adenocarcinomas (PDA). METHODS Ten PDA patients were enrolled. Each underwent 3 CT scans: a 4D-CT immediately following a CE 3D-CT and an individually optimized CE 4D-CT using test injection. Three physicians contoured the tumor and pancreatic tissues. We compared image quality scores, tumor volume, motion, tumor-to-pancreas contrast, and contrast-to-noise ratio (CNR) in the 3 CTs. We also evaluated interobserver variations in contouring the tumor using simultaneous truth and performance level estimation (STAPLE). RESULTS Average image quality scores for CE 3DCT and CE 4D-CT were comparable (4.0 and 3.8, respectively; P=0.47), and both were significantly better than that for 4D-CT (2.6, P<0.001). Tumor-to-pancreas contrast results were comparable in CE 3D-CT and CE 4D-CT (15.5 and 16.7 HU, respectively; P=0.71), and the latter was significantly higher than in 4D-CT (9.2 HU, P=0.03). Image noise in CE 3D-CT (12.5 HU) was significantly lower than in CE 4D-CT (22.1 HU, P<0.001) and 4D-CT (19.4 HU, P=0.005). CNRs were comparable in CE 3D-CT and CE 4DCT (1.4 and 0.8, respectively; P=0.23), and the former was significantly better than in 4D-CT (0.6, P = 0.04). Mean tumor volumes were smaller in CE 3D-CT (29.8 cm3 ) and CE 4D-CT (22.8 cm3 ) than in 4D-CT (42.0 cm3 ), although these differences were not statistically significant. Mean tumor motion was comparable in 4D-CT and CE 4D-CT (7.2 and 6.2 mm, P=0.23). Interobserver variations were comparable in CE 3D-CT and CE 4D-CT (Jaccard index 66.0% and 61.9%, respectively) and were worse for 4D-CT (55.6%) than CE 3D-CT. CONCLUSION CE 4D-CT demonstrated characteristics comparable to CE 3D-CT, with high potential for simultaneously delineating the tumor and quantifying tumor motion with a single scan. Supported in part by Philips Healthcare.

SU-E-J-187: Individually Optimized Contrast-Enhancement 4D-CT for Pancreatic Adenocarcinoma in Radiotherapy Simulation

PURPOSE To study the feasibility of individually optimized contrastenhancement (CE) 4D-CT for pancreatic adenocarcinoma (PDA) in radiotherapy simulation. To evaluate the image quality and contrast enhancement of tumor in the CE 4D-CT, compared to the clinical standard of CE 3D-CT and 4D-CT. METHODS In this IRB-approved study, each of the 7 PDA patients enrolled underwent 3 CT scans: a free-breathing 3D-CT with contrast (CE 3D-CT) followed by a 4D-CT without contrast (4D-CT) in the first study session, and a 4D-CT with individually synchronized contrast injection (CE 4D-CT) in the second study session. In CE 4D-CT, the time of full contrast injection was determined based on the time of peak enhancement for the test injection, injection rate, table speed, and longitudinal location and span of the pancreatic region. Physicians contoured both the tumor (T) and the normal pancreatic parenchyma (P) on the three CTs (end-of-exhalation for 4D-CT). The contrast between the tumor and normal pancreatic tissue was computed as the difference of the mean enhancement level of three 1 cm3 regions of interests in T and P, respectively. Wilcoxon rank sum test was used to statistically compare the scores and contrasts. RESULTS In qualitative evaluations, both CE 3D-CT and CE 4D-CT scored significantly better than 4D-CT (4.0 and 3.6 vs. 2.6). There was no significant difference between CE 3D-CT and CE 4D-CT. In quantitative evaluations, the contrasts between the tumor and the normal pancreatic parenchyma were 0.6±23.4, -2.1±8.0, and -19.6±28.8 HU, in CE 3D-CT, 4D-CT, and CE 4D-CT, respectively. Although not statistically significant, CE 4D-CT achieved better contrast enhancement between the tumor and the normal pancreatic parenchyma than both CE 3D-CT and 4DCT. CONCLUSION CE 4D-CT achieved equivalent image quality and better contrast enhancement between tumor and normal pancreatic parenchyma than the clinical standard of CE 3D-CT and 4D-CT. This study was supported in part by Philips Healthcare.

SU-E-I-92: Application of Dose Modulation for the Clinic

Purpose: To investigate the application of different CT dose modulation techniques on image quality for general and critical ill patients in the hospital setting. Methods: Automatic current selection (or dose modulation) has been a major dose reduction technique which becomes standard feature available from all major CT scanner vendors. However, each vendor approaches the issue differently, and the effect of this technique for patients with different clinical indications varies dramatically. Abdominal studies present the most challenging situation because the level of contrast detectability required for diagnostic quality of CTimages of this region. Tube currents for each image slice have been manually recorded and plotted against the scout images for both angular and longitudinal modulation cases. Results: For most chest/abdomen/pelvis studies, the tube current experiences a minimum below the diaphragm, as the computer system adjust the tube current in real time lacks the anatomy. This poses a risk for oncology patients that are under routine follow up for small metastasis in the liver and/or other upper GI organs. It will be more beneficial not using these techniques for these patients. Outpatient management has been changed to provide better image quality and lower radiation dose for the patients. Conclusions: Specific continued education for operators and quality control is very important for the optimum application of new techniques developed for clinical uses.