Evaluation of Lower-Dose Spiral Head CT for Detection of Intracranial Findings Causing Neurologic Deficits

Abstract

BACKGROUND AND PURPOSE: Despite the frequent use of unenhanced head CT for the detection of acute neurologic deficit, the radiation dose for this exam varies widely. Our aim was to evaluate the performance of lower-dose head CT for detection of intracranial findings resulting in acute neurologic deficit. MATERIALS AND METHODS: Projection data from 83 patients undergoing unenhanced spiral head CT for suspected neurologic deficits were collected. Cases positive for infarction, intra-axial hemorrhage, mass, or extra-axial hemorrhage required confirmation by histopathology, surgery, progression of findings, or corresponding neurologic deficit; cases negative for these target diagnoses required negative assessments by two neuroradiologists and a clinical neurologist. A routine dose head CT was obtained using 250 effective mAs and iterative reconstruction. Lower-dose configurations were reconstructed (25-effective mAs iterative reconstruction, 50-effective mAs filtered back-projection and iterative reconstruction, 100-effective mAs filtered back-projection and iterative reconstruction, 200-effective mAs filtered back-projection). Three neuroradiologists circled findings, indicating diagnosis, confidence (0-100), and image quality. The difference between the jackknife alternative free-response receiver operating characteristic figure of merit at routine and lower-dose configurations was estimated. A lower 95% CI estimate of the difference greater than À0.10 indicated noninferiority.

Spiral Computed Tomography in the Quantitative Measurement of the Adjacent Structure of the Left Atrial Appendage in Patients with Atrial Fibrillation

“…It mainly produces an impedance thermal effect on the local tissues, evaporating and drying the water in cardiomyocytes, forming a small, well-defined circular or oval coagulative necrosis to achieve the purpose of ablation [ 3 ]. After more than 20 years of development, improvement, and clinical popularity, radiofrequency ablation has gradually become the main way of the radical treatment of cardiac arrhythmias and the first-line clinical treatment modality [ 4 ]. It can cure a variety of arrhythmias, including atrial tachycardia, atrial tachycardia, paroxysmal ventricular tachycardia, early atrial fibrillation, and atrial tachycardia.…”

Low‐dose CT image and projection dataset

“…As additional examples of the value of these data, within our own research program and clinical practice, we have used these and other data to. determine optimal protocol settings in our large subspecialty clinical practice, 35–38 conduct multireader, multicase (MRMC) studies to discern the impact of different reconstruction algorithms, patient dose levels and other factors on radiologist diagnostic performance and confidence, 12–16,20,35–37,39,40 develop, and evaluate using MRMC studies, nonlocal means and deep learning‐based image denoising methods, 41–43 and develop model observers and deep learning methods from phantom or patient data to predict human observer performance of radiologists when interpreting patient data to allow rapid optimization of protocols for any scanner model, exam type, or patient characteristics 17–19 …”

“…A subset of cases from this data library has been successfully used for such studies. [12][13][14][15][16][17][18][19] Since conducting the 2016 Low Dose CT Grand Challenge, 16 in conjunction with the American Association of Physicists in Medicine and support from NIH awards EB017095 and EB017185, over 500 investigators from over 40 countries have requested access to the 30 abdominal CT studies used in the Grand Challenge. In the first 2 weeks after the data library was made public, over 22 TB of data consisting of nearly 7000 image series have been downloaded (one scan results in one image series and one projection data series).…”

“…To evaluate the impact of these effects on the ability of human observers to perform clinically relevant tasks, multireader, multicase observer performance studies and model observer performance studies have become essential to adequately demonstrate the ability of a new algorithm to maintain or exceed a desired level of diagnostic performance under the condition of reduced patient radiation dose. A subset of cases from this data library has been successfully used for such studies 12–19 . Since conducting the 2016 Low Dose CT Grand Challenge, 16 in conjunction with the American Association of Physicists in Medicine and support from NIH awards EB017095 and EB017185, over 500 investigators from over 40 countries have requested access to the 30 abdominal CT studies used in the Grand Challenge.…”

An interactive eye‐tracking system for measuring radiologists' visual fixations in volumetric CT images: Implementation and initial eye‐tracking accuracy validation

“…20,22 To address these challenges, an interactive eyetracking platform was developed that integrates the data from a state-of -the-art eye-tracking device with data from a custom workstation developed to measure radiologist diagnostic performance. [23][24][25][26] This system collects the real-time eye-tracking data as readers freely interact with the images from a volumetric CT dataset. Further, the platform can be operated in two data acquisition modes, one where the reader's head movement is stabilized using a chin rest and one where it is not, yet audible cues are provided to alert readers when their head position is outside of specified tolerances.…”