Role of Endoscopic Ultrasound in Staging and Vascular Assessment of Pancreatic Cancer.

Introduction Computed tomography (CT) of the abdomen with contrast stands as the gold standard for assessing pancreatic cancer, encompassing both staging and vascular analysis. However, not all patients are suitable candidates for contrast-enhanced CT (CECT) scans due to factors such as contrast agent allergies, pregnancy, renal impairment, radiation risks, and limited tissue sampling capability in CECT scans of the abdomen. In light of these challenges, this study evaluated the diagnostic capabilities of endoscopic ultrasound (EUS) compared to CECT for staging and vascular assessment of pancreatic cancer. Methods Fifty patients diagnosed with pancreatic cancer underwent evaluations using both CECT scans and EUS, focusing on staging and vascular invasion assessment. Vascular evaluation was carried out using a categorization system based on EUS findings, classifying them into three types based on the tumor-vessel relationship: Type 1 indicating clear invasion or encasement of a vessel by a tumor or contact with a vessel wall exceeding 180 degrees, Type 2 representing abutment, wherein a tumor contacts a vessel wall but at an angle less than 180 degrees, and Type 3 implying clear non-invasion, where a discernible distance exists between a tumor and a vessel. In this categorization, Type 1 and Type 2 indicated signs of vascular invasion, while Type 3 indicated vascular non-invasion. These findings were subsequently compared to the results from CECT scans. The endoscopist performing EUS was blinded to the CT outcomes prior to the examination. Results Regarding pancreatic cancer staging, EUS exhibited remarkable sensitivity, specificity, and accuracy rates of 100% according to the T criterion.As for vascular invasion assessment, EUS demonstrated sensitivity, specificity, and accuracy of 100%, 95.93%, and 96%, respectively, for venous invasion. For arterial invasion, the figures were 95.65% sensitivity, 100% specificity, and an overall accuracy of 99.5%. Conclusion EUS is an effective modality for evaluating both staging and vascular invasion in pancreatic cancer, boasting exceptional sensitivity, specificity, and accuracy rates. The findings are robust enough to consider EUS a viable alternative to CT scans in evaluation, with the added advantage of EUS offering tissue sampling capability.

Canadian Association of Radiologists Practice Guidelines for Computed Tomography Colonography.

Colon cancer is the third most common malignancy in Canada. Computed tomography colonography (CTC) provides a creditable and validated option for colon screening and assessment of known pathology in patients for whom conventional colonoscopy is contraindicated or where patients self-select to use imaging as their primary modality for initial colonic assessment. This updated guideline aims to provide a toolkit for both experienced imagers (and technologists) and for those considering launching this examination in their practice. There is guidance for reporting, optimal exam preparation, tips for problem solving to attain high quality examinations in challenging scenarios as well as suggestions for ongoing maintenance of competence. We also provide insight into the role of artificial intelligence and the utility of CTC in tumour staging of colorectal cancer. The appendices provide more detailed guidance into bowel preparation and reporting templates as well as useful information on polyp stratification and management strategies. Reading this guideline should equip the reader with the knowledge base to perform colonography but also provide an unbiased overview of its role in colon screening compared with other screening options.

Retrohepatic IVC injury: A new treatment approach with arterial stent graft.

Traumatic injuries to the inferior vena cava (IVC) are rare and among the most dreadful injuries encountered in evaluation of both penetrating and blunt traumatic settings. Clinical outcome of IVC injury is multifactorial with injuries being classically managed surgically. In this report, we present a case of 52 years old male patient with successfully treated blunt retrohepatic IVC injury utilizing arterial stent graft and anticoagulation regime without short-term complications. Evidence based standardized approach for endovascular management of IVC injury is not yet available. We hope that our report can contribute to worldwide procedure and postprocedural anticoagulation standardization.

Impact of Dual-Energy CT in the Emergency Department: Increased Radiologist Confidence, Reduced Need for Follow-Up Imaging, and Projected Cost Benefit.

OBJECTIVE. The purpose of this study was to analyze the contribution of dual-energy CT (DECT) to radiologist interpretation in the emergency department (ED) to determine whether recommendations for follow-up imaging decrease. MATERIALS AND METHODS. Reports of all DECT studies performed in an ED in 2016 were reviewed. A board-certified radiologist noted the number of times a report indicated that use of DECT techniques contributed to radiologist interpretation. For studies containing DECT findings in the report, the mixed datasets, representing conventional CT images, were read again separately. The difference between the numbers of follow-up studies recommended after conventional CT and DECT was converted into U.S. dollars by use of the Medicare fee schedule to estimate a projected cost benefit due to any reduction in follow-up imaging. RESULTS. The study included 3159 cases. DECT findings potentially altered management in 298 (9.4%) cases, increased diagnostic confidence in 455 (14.4%) cases, provided relevant information in 174 (5.6%) cases, helped characterize an incidental finding in 44 (1.4%) cases, and were mentioned to be noncontributory in three (0.09%) cases. DECT was not mentioned in the report in 2272 cases (71.9%). DECT findings avoided 162-191 recommended follow-up MRI examinations, 21-28 CT examinations, and 2-25 US examinations compared with conventional CT alone. The DECT findings also prompted one additional recommended interventional angiography procedure, one ventilation-perfusion scan, and one imaging-guided biopsy. The projected net cost reduction was $52,991.53-61,598.44. CONCLUSION. DECT added value to routine ED imaging by increasing diagnostic confidence, leading to a reduction in the number of recommended follow-up studies and a projected cost benefit.

The Role of Emergency Radiology in COVID-19: From Preparedness to Diagnosis [Formula: see text].

Emergency trauma radiology, although a relatively new subspecialty of radiology, plays a critical role in both the diagnosis/triage of acutely ill patients, but even more important in providing leadership and taking the lead in the preparedness of imaging departments in dealing with novel highly infectious communicable diseases and mass casualties. This has become even more apparent in dealing with COVID-19, the disease caused by the novel coronavirus SARS-CoV-2, first emerged in late 2019. We review the symptoms, epidemiology, and testing for this disease. We discuss characteristic imaging findings of COVID-19 in relation to other modern coronavirus diseases including SARS and MERS. We discuss roles that community radiology clinics, outpatient radiology departments, and emergency radiology departments can play in the diagnosis of this disease. We review practical methods to reduce spread of infections within radiology departments.

A PSA for Radiologists: Pictorial Review of Incidentalomas on Prostate Magnetic Resonance Imaging.

Multiparametric magnetic resonance imaging (MRI) of the prostate is a powerful and increasingly utilized imaging study for the diagnosis, staging, and surveillance of prostate cancer. With greater adoption by clinicians, it is becoming more common for incidental findings to be first detected on prostate MRI. Inadequate description of clinically significant findings may not prompt appropriate patient management, while over-reporting of indolent findings comes at increased patient anxiety, cost of workup, and iatrogenic risk. This review article aims to improve awareness, review pathophysiology, and present key imaging features of incidental findings seen on prostate MRI, ranging from common to rare and from benign to clinically significant.

Dual-Energy CT in Evaluation of the Acute Abdomen.

Evaluation of the nontraumatic acute abdomen with multidetector CT has long been accepted and validated as the reference standard in the acute setting. Dual-energy CT has emerged as a promising tool, with multiple clinical applications in abdominal imaging already demonstrated. With its ability to allow characterization of materials on the basis of their differential attenuation when imaged at two different energy levels, dual-energy CT can help identify the composition of internal body constituents. Therefore, it is possible to selectively identify iodine to assess the enhancement pattern of an organ, including the identification of hyperenhancement in cases of inflammatory processes, or ischemic changes secondary to vascular compromise. Quantification of iodine uptake with contrast material-enhanced dual-energy CT is also possible, and this quantification has been suggested to be useful in differentiating inflammatory from neoplastic conditions. Dual-energy CT can help determine the composition of gallstones and urolithiasis and can be used to accurately differentiate uric acid urinary calculi from non-uric acid urinary calculi. Moreover, dual-energy CT is capable of substantially reducing artifacts caused by metallic prostheses, to improve the imaging evaluation of abdominopelvic organs. The possibility of creating virtual nonenhanced images in the evaluation of acute aortic syndrome, gastrointestinal hemorrhage and ischemia, or pancreatic pathologic conditions substantially reduces the radiation dose delivered to the patient, by eliminating a true nonenhanced acquisition. Finally, by increasing the iodine conspicuity, contrast-enhanced dual-energy CT can render an area of free active extravasation or endoleak more visible, compared with conventional single-energy CT. This article reviews the basics of dual-energy CT and highlights its main clinical applications in evaluation of the nontraumatic acute abdomen. ©RSNA, 2019.

Virtual monoenergetic reconstruction of contrast-enhanced CT scans of the abdomen and pelvis at 40 keV improves the detection of peritoneal metastatic deposits.

PURPOSE: To evaluate the role of virtual monoenergetic imaging (VMI) in the detection of peritoneal metastatic disease in contrast-enhanced computed tomography (CT) of the abdomen and pelvis and to compare this technique to the conventional 120 kV mixed dataset. MATERIALS AND METHODS: Institutional review board approval was obtained with no informed consent required for this retrospective analysis. 43 consecutive patients with histopathologically confirmed peritoneal disease were scanned using a standard protocol on a 128-section dual-source, dual-energy CT system (100/140 keV). Scans were retrospectively reconstructed at VMI energy levels from 40-110 keV in 10 keV increments and were analyzed both quantitatively and qualitatively. CNR values for peritoneal metastatic deposits were recorded using region of interest (ROI) analysis at each energy level for all VMI datasets. Subjective analysis was performed by two independent fellowship-trained readers with combined experience of greater than 15 years. Qualitative parameters included diagnostic acceptability, subjective noise, and contrast resolution and confidence. RESULTS: The contrast-to-noise ratios (CNRs) for peritoneal metastatic deposits at the different VMI energy levels were compared using a one-way ANOVA with Tukey Post Test, and the optimal CNR was observed at 40 keV (p < 0.0001). Qualitative parameters were compared using a Paired T Test. Subjective noise, diagnostic acceptability, and contrast resolution was significantly better on the conventional images, but readers reported increased confidence on VMI at 40 keV (p < 0.001). CONCLUSION: VMI reconstruction of contrast-enhanced dual-energy CT scans of the abdomen and pelvis at 40 keV maximizes the conspicuity of metastatic peritoneal deposits and improves radiologists' diagnostic confidence compared with conventional CT images. We recommend using virtual monoenergetic datasets at 40 keV as a tool for improving the detection of these lesions in routine clinical practice.

Dual-Energy CT in Differentiating Nonperforated Gangrenous Appendicitis From Uncomplicated Appendicitis.

OBJECTIVE: The hypothesis of this study was that the use of dual-energy spectral techniques in CT can improve accuracy in the diagnosis of acute gangrenous appendicitis. MATERIALS AND METHODS: This retrospective study included 209 patients with a pathologic diagnosis of appendicitis. Two board-certified abdominal radiologists reviewed 120-kV simulated images, 40-keV virtual monoenergetic images, and color-coded iodine overlay images. Sensitivity, specificity, positive and negative predictive values (PPV and NPV), accuracy, and interobserver agreement were calculated for each set of images. RESULTS: Forty-four patients (21.0%) had histopathologic results positive for gangrenous appendicitis. The sensitivity of 40-kV virtual monoenergetic imaging was 100% (44/44); specificity, 81.2% (134/165); PPV, 58.7% (44/75); NPV, 100% (134/134); accuracy, 85.2%; and interobserver agreement, 0.99. The corresponding values for the iodine overlay imaging datasets were 100% (44/44), 80.0% (132/165), 57.1% (44/77), 100% (132/132), 84.2%, and 0.99 and for 120-kV simulated imaging were 22.7% (10/44), 96.4% (159/165), 62.5% (10/16), 82.4% (159/193), 77.5%, and 0.93. All cases of gangrenous appendicitis had true-positive results of virtual monoenergetic and iodine overlay imaging. There were no false-negative results of virtual monoenergetic or iodine overlay imaging. CONCLUSION: In cases of suspected appendicitis, dual-energy CT that includes virtual monoenergetic and iodine overlay imaging is accurate for confirming and excluding the presence of gangrenous appendicitis with high sensitivity and specificity.

What Are the Expected Findings on Follow-up Computed Tomography Angiogram in Post-traumatic Patients With Blunt Cerebrovascular Injury?

PURPOSE: Blunt cerebrovascular injury (BCVI) is a rare but potentially devastating diagnosis. Our study establishes the temporal changes and findings on follow-up imaging. METHODS: For this retrospective, institutional review board-approved study, the hospital trauma registry was queried for all severely injured polytrauma patients who underwent computed tomography angiogram (CTA) scans in the emergency department between January 1, 2010, and December 31, 2016, with injury severity score ≥16, yielding 3747 patients. A total of 128 patients had a follow-up CTA for BCVI. The grade, location, and outcomes of injuries on follow-up imaging were studied. RESULTS: A vehicular collision was the most common mechanism of injury (75%). The majority of patients (61%) had a Glasgow Coma Scale of 10-15. Vertebral fractures were the most common associated injury (57%). The overall incidence of BCVI in our study population was 4.8%. On the initial CTA, 50% of injuries were grade 1, 25.4% were grade 2, 7% were grade 3, 17% were grade 4, and 0.6% were grade 5. For the different grades of injuries, improvement has been documented in 44% with complete healing in 34%, while 51% of injuries remained unchanged from the initial scan. Only 5% progressed to a higher-grade injury. Twelve patients developed strokes with an incidence of 9.4% in patients with a follow-up CTA. CONCLUSIONS: This study can help increase the awareness of radiologists about the evolution patterns of different grades of BCVIs on follow-up CTA for severely injured posttraumatic patients.

Dual-Energy CT Iodine Mapping and 40-keV Monoenergetic Applications in the Diagnosis of Acute Bowel Ischemia.

OBJECTIVE: Sensitivity of CT of the abdomen for detection of acute bowel ischemia (ABI) can be as low as 60%. In this study, we assessed the diagnostic performance of iodine-map and monoenergetic (40-keV) images in patients with suspected ABI. MATERIALS AND METHODS: This retrospective study included 60 consecutive patients with suspected ABI who underwent a standardized imaging protocol dual-source dual-energy CT (DECT) over a 26-month period. Clinical and operative outcomes were recorded as the reference standard. Two abdominal radiologists who were unaware of clinical and surgical information independently assessed conventional CT images for ABI. After a time interval designed to reduce recall, readers reassessed conventional images with supplementary iodine-map and 40-keV postprocessed images. Quantitative ROI analysis was also performed. RESULTS: ABI was observed in 11 patients. For reader A, sensitivity was 63.6% (95% CI, 30.8-89.1%) when interpreting conventional images alone. Sensitivity for detection of ABI increased to 81.8% (95% CI, 48.2-97.7%) and 100% (95% CI, 71.5-100%) when iodine-map and 40-keV images were assessed, respectively. For reader B, no change in sensitivity was seen with either technique, but the number of false-positives were reduced with supplementary iodine-map and 40-keV postprocessed images. Interobserver agreement was fair with conventional images (κ = 0.29) but improved to moderate (κ = 0.45) and substantial (κ = 0.63) with iodine-map and 40-keV images, respectively. Quantitative assessment found significant differences in iodine uptake (1.01 ± 0.55 mg/mL vs 3.04 ± 1.19 mg/mL) and mean attenuation (75.2 ± 38.4 HU vs 163.5 ± 48.9 HU) between nonischemic and ischemic segments, respectively. CONCLUSION: Iodine-map and 40-keV monoenergetic images increase conspicuity of ABI, resulting in improved diagnostic accuracy compared with review of conventional CT images alone.

Practical Applications of Dual-Energy Computed Tomography in the Acute Abdomen.

With new developments in workflow automation, as well as technological advances enabling faster imaging with improved image quality and dose profile, dual-energy computed tomography is being used more often in the imaging of the acutely ill and injured patient. Its ability to identify iodine, differentiate it from hematoma or calcification, and improve contrast resolution has proven invaluable in the assessment of organ perfusion, organ injury, and inflammation.

Pheochromocytomas Versus Adenoma: Role of Venous Phase CT Enhancement.

OBJECTIVE: Our objective was to investigate whether the quantitative measurement of venous phase enhancement on CT can distinguish a pheochromocytoma from an adrenal adenoma. MATERIALS AND METHODS: A pathology database was retrospectively appraised over a period of 7 years and revealed 43 histopathologically proven adrenal adenomas and 34 pheochromocytomas. The lesion densities were measured on the 60-second venous phase CT on all adrenal lesions to assess venous phase enhancement values. RESULTS: Venous phase enhancement of 85 HU or greater afforded a sensitivity, specificity, positive predictive value, and negative predictive value of 88.2%, 83.7%, 81.1%, and 90%, respectively (p < 0.0001). The positive likelihood ratio was 5.42. Venous phase enhancement of ≥ 85 HU was detected in 30 (88.2%) pheochromocytomas (p < 0.001) and in seven (16.3%) adenomas. Venous phase enhancement of < 85 HU was detected in four (11.8%) pheochromocytomas and in 36 (83.7%) adenomas. Of the pheochromocytomas imaged with a triphasic protocol (n = 15), 66.7% (n = 10) met both absolute and relative percentage washout criteria for the diagnosis of a lipid-poor adenoma (p > 0.1). CONCLUSION: A significant subset of pheochromocytomas mimics adenomas on absolute or relative percentage washout calculations. However, nodules with venous phase enhancement of 85 HU or more are much more likely to be pheochromocytomas than adenomas, regardless of whether the lesion shows absolute or relative percentage washout compatible with a lipid-poor adenoma. The typical values of absolute and relative percentage washout of adrenal adenoma should be interpreted along with the venous phase enhancement value to avoid potential misdiagnoses.

Correction to: Delayed manifestations of abdominal trauma: follow-up abdominopelvic CT in posttraumatic patients.

The original version of this article unfortunately contained few mistakes. Under the subheading "Data extraction and review process", in line 12 the word "prospective" is incorrectly given by the author. The correct word is "retrospective". In Fig. 2D, the label should read as RA instead of LA. In Table 6, the word "ischemic/gangrenous" should read as "ischemia/gangrene" in 9th row, column 6. The revised Fig 2 and Table 6 are available in the correction article.

Diagnostic Imaging in Disasters: A Bibliometric Analysis.

OBJECTIVE: To investigate the role of diagnostic imaging in the clinical diagnosis, treatment, and follow-up management of patients in response to disasters. METHODS: A MEDLINE (OVID) search of original research articles identified 177 articles on this topic published since 2000. A bibliometric analysis was conducted on the top 100 articles ranked by average yearly citation. RESULTS: The most frequently studied disaster categories were disease outbreak (55 articles), armed conflict (23 articles), terrorist incident (10 articles), and earthquake (7 articles). The most studied disasters were the H1N1 influenza outbreak in 2009 (28 articles), Severe Acute Respiratory Syndrome outbreak in 2003 (24 articles), War in Afghanistan, 2001-2014 (8 articles), Iraq War, 2003-2011 (6 articles), and the Sichuan earthquake (China) in 2008 (6 articles). Among the first authors, 59 were primarily affiliated with Radiology. The United States of America produced the most articles (25 articles), followed by the People's Republic of China (24 articles). Eighty-one studies were retrospective, with 19 studies being prospective. Computed tomography was the most investigated modality (52.8%), followed by conventional radiography (33.3%) and ultrasound (9.7%). CONCLUSIONS: Our study identifies intellectual milestones in the utility of diagnostic imaging in response to various disasters, and could help guide future research in developing disaster management plans. (Disaster Med Public Health Preparedness. 2018;12:265-277).

The Top 100 Most-Cited Articles in Stroke Imaging: A Bibliometric Analysis.

PURPOSE: The goal of our study was to compile a list of the top 100 most-cited articles in stroke imaging literature across all peer-reviewed scientific journals. These articles were then analyzed to identify current trends in stroke imaging research and determine the characteristics of highly-cited articles. MATERIALS AND METHODS: A database of the top 100 most-cited articles was created using Scopus and Web of Science. Articles were reviewed for applicability by 2 fellowship-trained radiologists with over 10 years of combined experience in neuroimaging. The following information was collected from each article: Article Title, Scopus Citations, Year of Publication, Journal, Journal Impact Factor, Authors, Number of Institutions, Country of Origin, Study Topic, Study Design, and Sample Size. RESULTS: Citations for the top 100 most-cited articles ranged from 159-810, and citations per year ranged from 5.7-516.0. Most of articles were published between 1996 and 2000 (n = 43). Articles were published across 18 journals, most commonly in Stroke (n = 40). Magnetic resonance imaging was the focus in 46 articles, computed tomogrphy in 16, and functional magnetic resonance imaging in 10. The most common study topic is prognostic use of an imaging modality (n = 27). CONCLUSIONS: Our study helps to characterize the field and identify the characteristics of most-cited articles.

Delayed manifestations of abdominal trauma: follow-up abdominopelvic CT in posttraumatic patients.

PURPOSE: Our study aims to investigate the frequency and patterns of delayed manifestations of abdominal and pelvic injuries which may not be identified or which fail to manifest on the initial abdominopelvic CT in posttraumatic patients. METHODS: For our institutional review board (IRB)-approved retrospective study, our hospital trauma registry was queried for patients with blunt multitrauma and Injury Severity Score (ISS) ≥ 16 between January 2010 and August 2016, yielding 3735 patients. A total of 203 patients received a follow-up abdominopelvic CT within six months from the initial scan and those with new findings on follow-up CT were identified. A retrospective blinded review of the initial CT examinations was performed by two experienced radiologists. The retrospective readings and original reports were compared to categorize the new abnormalities detected on follow-up CT scans. The categories included missed injuries, late presentations and sequelae of trauma, and complications of surgery, hospital admission, and invasive procedures. The patients' notes were reviewed for the clinical indications, time interval for repeat CT examination, and subsequent clinical management. The software used for statistical analysis of the extracted data was Microsoft Excel for Mac (version 15.33). RESULTS: Out of 3735 patients, 203 patients received 232 follow-up abdominopelvic CTs. The average elapsed time between the initial CT and the follow-up CT was 15 ± 27 days. Evaluation for an abdominal fluid collection was the most common clinical indication, accounting for 40% of the total number (n = 243) of indications. Delayed manifestations and complications of trauma were present in 41 patients due to 47 abnormalities, most commonly related to solid organ injury, followed by abdominal collections and hematoma. Twenty-nine CT findings (62%) were only detectable on follow-up CT, while nine injuries (19%) were missed on initial CT. The findings on repeated CT warranted eight surgical and 15 interventional procedures. CONCLUSION: A small percentage of traumatic injuries may be unidentified or fail to manifest on the initial CT, resulting in delayed manifestations of abdominopelvic trauma, which may lead to subsequent readmission, delayed management, and more severe medical complications.

Unenhanced Dual-Energy Computed Tomography: Visualization of Brain Edema.

PURPOSE: The aim of this study was to determine whether dual-energy computed tomography (DECT) imaging is superior to conventional noncontrast computed tomography (CT) imaging for the detection of acute ischemic stroke. MATERIALS AND METHODS: This was a retrospective, single-center study of 40 patients who presented to the emergency department (ED) of a major, acute care, teaching center with signs and symptoms of acute stroke. Only those patients who presented to the ED within 4 hours of symptom onset were included in this study. All 40 patients received a noncontrast DECT of the head at the time of presentation. Each patient also received standard noncontrast CT of the head 24 hours after their initial presentation to the ED. "Brain edema" images were then reconstructed using 3-material decomposition with parameters adjusted to suppress gray/white matter contrast while preserving edema and increasing its conspicuity. The initial unenhanced, mixed images, brain edema, and 24-hour follow-up true noncontrast (TNC) images were reviewed and assigned Alberta Stroke Program Early CT scores. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. RESULTS: Of the 40 patients, 28 (70%) were diagnosed with an acute infarction. Brain edema reconstructions were better able to predict end infarction volume, with Alberta Stroke Program Early CT scores similar to the 24-hour follow-up TNC CT (7.75 vs 7.7; P > 0.05), whereas the mixed images routinely underestimated the extent of infarction (8.975 vs 7.7; P < 0.001). Initial TNC images had a sensitivity, specificity, PPV, and NPV of 80% (95% confidence interval [CI], 51.9%-95.7%), 72.7% (95% CI, 39%-94%), 80% (95% CI, 51.9%-95.7%), and 72.73% (95% CI, 51.91%-95.67%), respectively. The DECT brain edema images provided a sensitivity, specificity, PPV, and NPV of 93.33% (95% CI, 68.05%-99.83%), 100% (95% CI, 71.51%-100%), 100% (95% CI, 76.84%-100%), and 91.67% (95% CI, 61.52%-99.79%), respectively. There was very good interrater reliability across all 3 imaging techniques. CONCLUSION: Brain edema reconstructions are able to more accurately detect edema and end-infarct volume as compared with initial TNC images. This provides a better assessment of the degree and extent of infarction and may serve to better guide therapy in the future.