Abstract 60: Multiphase versus Single Phase CT Angiography for Detection of Distal Intracranial Occlusion

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Brendan Diederichs ◽  
Bijoy Menon ◽  
Patricia Jo ◽  
Carla Wallace ◽  
Morgan Willson ◽  
...  
Keyword(s):  
Single Phase ◽  
White Matter Lesion ◽  
Relative Rate ◽  
Arterial Occlusion ◽  
Radiology Resident ◽  
Unenhanced Ct ◽  
Iodinated Contrast ◽  
Enhanced Ct ◽  
Contrast Bolus ◽  
Mr Brain

Introduction: Detecting distal intracranial arterial occlusion is of increasing importance as current studies begin to evaluate the potential benefit of tPA in minor acute stroke. Multiphase CTA (mCTA) is a technique used routinely at our centre in the setting of suspected acute ischemic stroke (AIS). Hypothesis: We hypothesized that mCTA is diagnostically superior to CTA for detection of distal intracranial arterial occlusion in suspected AIS. Methods: Population comprised of patients with suspected AIS who had mCTA, followed by MR brain with DWI within 24 hours. mCTA involves 3 phases of enhanced CT from skull base to vertex following administration of a single iodinated contrast bolus. Prospective interpretation of unenhanced CT followed by single phase CTA was performed by a radiology resident, a stroke fellow, or a neuroradiologist. Unenhanced CT followed by mCTA was interpreted > 1 week after single phase CTA interpretation using the same dataset. MR exams were separately adjudicated to establish each case as positive or negative according to pre-specified criteria that suggests a high likelihood for the presence of an arterial occlusion on CTA (DWI lesion > 2mm diameter, not multiple small infarcts consistent with microembolic shower, not exclusively white matter lesion, not small deep gray matter lesion consistent with lacunar type infarct. Results and Conclusion: Of 322 patients, single phase CTA detected 69 occlusions (sensitivity 52.5%, specificity 98.1%) and mCTA detected 113 (sens = 81.8%, spec = 99.5%). mCTA detected a greater number of proximal occlusions (76 vs. 66), and a greater number of distal occlusions (37 vs. 3) than CTA. mCTA demonstrated a greater rate of detection for distal occlusions (relative rate = 9.67, 95% CI 3.76 - 24.84). CTA/MR agreement was moderate (kappa = 0.59) while mCTA/MR agreement was substantial (kappa = 0.81). Mean interpretation time for CTA was 239.8 seconds (95% CI 221.3 - 258.4) and 195.0 seconds (95% CI 176.9 - 213.1) for mCTA. In conclusion, our data suggest mCTA is superior to single phase for detection of distal intracranial occlusion.

Comparison of liver SUV using unenhanced CT versus contrast-enhanced CT for attenuation correction in 18F-FDG PET/CT

2014 ◽  
Vol 35 (5) ◽  
pp. 472-477 ◽  
Author(s):  
Edwin E.G.W. ter Voert ◽  
Hanneke W.M. van Laarhoven ◽  
Peter J.M. Kok ◽  
Wim J.G. Oyen ◽  
Eric P. Visser ◽  
...  
Keyword(s):  
Attenuation Correction ◽  
Fdg Pet ◽  
Unenhanced Ct ◽  
Contrast Enhanced Ct ◽  
Contrast Enhanced ◽  
Pet Ct ◽  
Enhanced Ct ◽  
18F Fdg ◽  
Fdg Pet Ct

scholarly journals Intravenous Contrast Agent in Abdominal CT: Is It Really Needed to Identify the Cause of Bowel Obstruction? Proof of Concept

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Federica Vernuccio ◽  
Dario Picone ◽  
Gregorio Scerrino ◽  
Massimo Midiri ◽  
Giuseppe Lo Re ◽  
...  
Keyword(s):  
Small Bowel ◽  
Contrast Agent ◽  
Small Bowel Obstruction ◽  
Bowel Obstruction ◽  
Large Bowel ◽  
Large Bowel Obstruction ◽  
Intravenous Contrast ◽  
Unenhanced Ct ◽  
Enhanced Ct ◽  
Intravenous Contrast Agent

Background. To compare sensitivity of unenhanced computed tomography (CT) and contrast-enhanced CT for the identification of the etiology of bowel obstruction. Materials and Methods. We retrospectively evaluated abdominal CT scans of patients operated for bowel obstruction from March 2013 to October 2017. Two radiologists evaluated CT scans before and after contrast agent in two reading sessions. Then, we calculated sensitivity of CT in the diagnosis of bowel obstruction and determined in which cases the etiology of bowel obstruction was detected on both unenhanced and enhanced CT or on enhanced CT only. The reference standard was defined as the final diagnosis obtained after surgery. Results. Eighteen patients (mean age 72±15 years, age range 37-88 years) were included in the study. Sensitivity of unenhanced CT and enhanced CT was not significantly different in either small bowel obstruction (64%, 7/11 patients vs. 73%, 8/11 patients; P=0.6547) or large bowel obstruction (71%, 5/7 patients vs. 100%, 7/7 patients; P=0.1410). Adhesions were identified on unenhanced CT as the etiology of small bowel obstruction in 80% (4/5) of patients. Tumors were identified on unenhanced CT as the etiology of large bowel obstruction in 67% (4/6) of patients. Conclusion. In the diagnosis of small bowel obstruction due to adhesions with normal bowel wall thickening and when a neoplasm is identified as the etiology of large bowel obstruction on unenhanced CT, an intravenous contrast agent may be avoided for the identification of the etiology. In remaining cases, contrast agent is still recommended.

Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In-Phase and Opposed-Phase MRI?

2019 ◽  
Vol 212 (3) ◽  
pp. 554-561 ◽  
Author(s):  
Lisa M. Ho ◽  
Ehsan Samei ◽  
Maciej A. Mazurowski ◽  
Yuese Zheng ◽  
Brian C. Allen ◽  
...  
Keyword(s):  
Texture Analysis ◽  
Unenhanced Ct ◽  
Contrast Enhanced Ct ◽  
Contrast Enhanced ◽  
Enhanced Ct ◽  
Ct Contrast

scholarly journals Estimation of nephron number in living humans by combining unenhanced computed tomography with biopsy-based stereology

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Takaya Sasaki ◽  
Nobuo Tsuboi ◽  
Yusuke Okabayashi ◽  
Kotaro Haruhara ◽  
Go Kanzaki ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Arterial Phase ◽  
Nephron Number ◽  
Living Kidney Donors ◽  
Explanatory Variables ◽  
Cortical Volume ◽  
Unenhanced Ct ◽  
Enhanced Ct ◽  
Phase Images ◽  
Unenhanced Computed Tomography

Abstract Methods for estimating nephron number in a clinical setting may be useful for predicting renal outcomes. This study aimed to establish such a method using unenhanced computed tomography (CT) and biopsy-based stereology. Patients or living kidney donors simultaneously subjected to enhanced and unenhanced CT examinations were randomly assigned to development and validation groups. The enhanced CT-measured arterial phase and the venous phase images of kidneys were regarded as the true values for cortical volume and parenchymal volume, respectively. Linear multiple regression analysis was used to create models for estimating cortical volume using explanatory variables including unenhanced CT-measured parenchymal volume. Nephron number was determined as the product of cortical volume and the glomerular density in biopsies of donors. Five equations for estimating cortical volume were created and verified. In donors, estimated nephron number by unenhanced CT was consistent with that by enhanced CT, with minimal errors in all models (636–655 ± 210–219 vs. 648 ± 224 × 103/kidney). Clinical characteristics combined with parenchymal volume did not improve the equation over parenchymal volume alone. These results support the feasibility of estimating nephron number by a combination of unenhanced CT and biopsy-based stereology, with a possible application for renal disease patients who are often not suitable for contrast media.

scholarly journals Nodule Classification on Low-Dose Unenhanced CT and Standard-Dose Enhanced CT: Inter-Protocol Agreement and Analysis of Interchangeability

2018 ◽  
Vol 19 (3) ◽  
pp. 516 ◽  
Author(s):  
Kyung Hee Lee ◽  
Kyung Won Lee ◽  
Ji Hoon Park ◽  
Kyunghwa Han ◽  
Jihang Kim ◽  
...  
Keyword(s):  
Low Dose ◽  
Standard Dose ◽  
Unenhanced Ct ◽  
Enhanced Ct ◽  
Nodule Classification

scholarly journals The value of unenhanced CT in the diagnosis of acute appendicitis

1998 ◽  
Vol 116 (6) ◽  
pp. 1838-1845 ◽  
Author(s):  
Giuseppe D'Ippolito ◽  
Giselle Guedes Netto de Mello ◽  
Jacob Szejnfeld
Keyword(s):  
Acute Appendicitis ◽  
Predictive Value ◽  
Preoperative Diagnosis ◽  
University Hospital ◽  
Ct Diagnosis ◽  
Unenhanced Ct ◽  
Enhanced Ct ◽  
Accuracy Study ◽  
Operative Findings ◽  
The University

OBJECTIVE: To establish the accuracy of unenhanced CT in the preoperative diagnosis of acute appendicitis. DESIGN: Accuracy study, prospective and blinded. SETTING: The University Hospital. PARTICIPANTS: 52 patients with clinical and laboratorial manifestations of acute appendicitis. CT diagnosis was made by: presence of an abnormal appendix, appendiceal calculi with pericecal phlegmon or alterations in the pericecal appendicular site and absence of signs that may lead to other diagnosis. MAIN OUTCOME MEASURES: Overall accuracy, comparing the tomographic aspects with the intra-operative findings and pathological reports ("gold standard"). RESULTS: Acute appendicitis was confirmed in 44 cases. Efficacy was 92%, sensitivity was 91%, specificity was 100%, positive predictive value was 100% and negative predictive value was 67%. CONCLUSIONS: Unenhanced CT presents a similar overall accuracy to that reported by other authors who studied enhanced CT diagnosis of acute appendicitis.

scholarly journals Temporal Correlation Analysis of Penumbral Dynamics in Focal Cerebral Ischemia

1996 ◽  
Vol 16 (1) ◽  
pp. 60-68 ◽  
Author(s):  
E. H. Lo ◽  
J. Rogowska ◽  
P. Bogorodzki ◽  
M. Trocha ◽  
K. Matsumoto ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Focal Cerebral Ischemia ◽  
Rabbit Model ◽  
Arterial Occlusion ◽  
Temporal Correlation ◽  
Correlation Technique ◽  
Bolus Transit ◽  
Iodinated Contrast ◽  
Ischemic Core ◽  
Over Time

A novel temporal correlation technique was used to map the first-pass transit of iodinated contrast agents through the brain. Transit profiles after bolus injections were measured with dynamic computed tomography (CT) scanning (1 image/s over 50 s). A rabbit model of focal cerebral ischemia (n = 6) was used, and dynamic CT scans were performed at 30, 60, 90, and 120 min postocclusion. Within the ischemic core, no bolus transit was detectable, demonstrating that complete ischemia was present after arterial occlusion. In the periphery of the ischemic distribution, transit dynamics showed smaller peaks, broadened profiles, and overall delay in bolus transit. A cross-correlation method was used to generate maps of delays in ischemic transit profiles compared with normal transit profiles from the contralateral hemisphere. These maps showed that penumbral regions surrounding the ischemic core had significantly delayed bolus transit profiles. Enlargement of the ischemic core over time (from 30 to 120 min postocclusion) was primarily accomplished by the progressive deterioration of the penumbral regions. These results suggest that (a) temporal correlation methods can define regions of abnormal perfusion in focal cerebral ischemia, (b) peripheral regions of focal cerebral ischemia are characterized by delays in bolus transit profiles, and (c) these regions of bolus transit delay deteriorate over time and thus represent a hemodynamic penumbra.

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