Body CT Studies Research Articles

Radiologists Make More Errors Interpreting Off-Hours Body CT Studies during Overnight Assignments as Compared with Daytime Assignments.

Background There is increasing research attention on the impact of overnight work on radiologist performance. Prior studies on overnight imaging interpretive errors have focused on radiology residents, not on the relative performance of board-eligible or board-certified radiologists at night compared with during the day. Purpose To analyze the rate of clinically important interpretation errors on CT examinations of the abdomen, pelvis, or both ("body CT studies") committed by radiology fellows working off-hours based on day or night assignment. Materials and Methods Between July 2014 and June 2018, attending physicians at one tertiary care institution reviewed all body CT studies independently interpreted off-hours by radiologists in an academic fellowship within 10 hours of initial interpretation. Discrepancies affecting acute or follow-up clinical care were classified as errors. In this retrospective study, the error rate for studies interpreted during the day (between 7:00 am and 5:59 pm) was compared with that of studies interpreted at night (between 6:00 pm and 6:59 am). Error rate in the first half of day and night assignments was compared with error rate in the latter half. Statistical analyses used χ2 tests and general estimating equations; significance was defined as P < .05. Results There were 10 090 body CT studies interpreted by 32 radiologists. Forty-four of 2195 daytime studies (2.0%) had errors compared with 240 of 7895 nighttime studies (3.0%; P = .02). Twenty-two of 32 (69%) radiologists had higher error rates for night cases (P = .03). There were more errors in the last half of a night assignment (125 of 3358, 3.7%; P = .002) compared with the first half (115 of 4537, 2.5%). Conclusion On the basis of a subspecialty review, clinically important off-hours body CT interpretation errors occurred more frequently overnight and more frequently in the latter half of assignments, with more radiologists having worse error rates at night compared with the day. © RSNA, 2020 See also the editorial by Bruno in this issue.

The degree of abdominal imaging (AI) subspecialization of the reviewing radiologist significantly impacts the number of clinically relevant and incidental discrepancies identified during peer review of emergency after-hours body CT studies.

To evaluate if and to what extent the degree of subspecialization in abdominal imaging (AI) affects rates of discrepancies identified on review of body CT studies initially interpreted by board-certified radiologists not specialized in AI. AI division radiologists at one academic medical center were classified as primary or secondary members of the division based on whether they perform more or less than 50% of their clinical duties in AI. Primary AI division radiologists were further subdivided based on whether or not they focus their clinical duties almost exclusively in AI. All AI radiologists performed subspecialty review of all after-hours body CT studies initially interpreted by any non-division radiologist. The discrepancies identified in the subspecialty review of consecutive after-hours body CT scans performed between 7/1/10 and 12/31/10 were analyzed and placed into one of three categories: (1) discrepancies that potentially affect patient care ("clinically relevant discrepancies", or CRD); (2) discrepancies that would not affect patient care ("incidental discrepancies", or ID); and (3) other types of comments. Rates of CRD and ID detection were compared between subgroups of Abdominal Imaging Division radiologists divided by the degree of subspecialization. 1303 studies met the inclusion criteria. Of 742 cases reviewed by primary members of the AI division, 33 (4.4%) had CRD and 78 (10.5%) had ID. Of 561 cases reviewed by secondary members of the AI division, 11 (2.0%) had CRD and 36 (6.5%) had ID. The differences between the groups for both types of discrepancies were statistically significant (p=0.01). When primary members of the AI division were further subdivided based on extent of clinical focus on abdominal imaging, rates of CRD and ID detection were higher for the subgroup with more clinical focus on abdominal imaging. The degree of AI subspecialization affects the rate of clinically relevant and ID identified in body CT interpretations initially rendered by board certified but non-abdominal imaging subspecialized radiologists.

Evaluation of Radiologist Interpretive Performance Using Blinded Reads by Multiple External Readers

To demonstrate a method of assessing radiologic diagnostic agreement utilizing multiple blinded external readers. Six body CT studies interpreted by one reader (primary reader) at the host institution were compiled with patient identifiers removed. Brief clinical histories that were available to the primary reader were provided. Radiologists at 22 centers participated and the interpretations were analyzed in aggregate with the consensus majority that served as the surrogate gold standard for each case. A total of 31 radiologists formed the group of secondary readers with two-thirds in academic practice averaging 8 years of experience (range: 1-25 years). The average findings per reader for cases A to F include: 1.9 (range: 1-5), 6.3 (range: 2-10), 10.4 (range: 7-14), 5.7 (range: 3-10), 4.2 (range: 2-8), and 3.8 (range: 1-7), respectively. There was agreement of the primary interpretation and the surrogate gold standard for each case. The results of our study demonstrate a wide range of interpretation, with wider ranges observed in more complex cases and with vague clinical complaints. Comparison to the primary reader required the use of aggregate analysis and an agreement percentage cutoff to minimize bias and the limitations of this type of study. An intensive evaluation of radiologist performance such as this could be considered in various settings such as a quality assurance program, intense scrutiny of an individual radiologist whether competency is in question, or for medicolegal purpose to ascertain standard of care.

Clinical evaluation of newly developed CRT viewing station: CT reading and observer's performance

The clinical performance of the new viewing station with six CRT monitors (17-inch, 1,024 × 1,280) was evaluated. In the primary interpretation of CT images, time measurements were carried out for eight radiologists. No significant differences in reading time existed between CRT and film in 3 of 4 readers in head CT series, and in 2 of 6 readers in body CT series. Compared with the previous system, the new prototype system achieved an approximately 30% decrease in reading time in both head and body CT studies and could reduce mental and eye fatigue.

Evaluation of a PACS Workstation for Assessment of Body CT Studies

Conventional hardcopy images from 266 body CT studies were compared with those provided at a commercially available picture archiving communication system (PACS) workstation. Unprocessed PACS images were larger but otherwise precisely duplicated hardcopy images. The PACS images were evaluated before and after application of various image processing/display features. Approximately three-quarters of the cases were depicted equally well with PACS and hardcopy, but in one quarter of the cases, diagnostic features were judged to be shown more clearly at the PACS workstation. When PACS images were viewed first, change in diagnosis after subsequent hardcopy inspection was infrequent (confidence change: 4%; different findings: 2%). Conversely, when hardcopy images were viewed first, change in diagnosis after subsequent PACS inspection was more frequent (confidence change: 19%; different findings: 8%). Specialized image manipulation available on PACS was critical for its performance. Review of cases with new findings discovered during the second inspection showed the majority of them to be clinically significant, true-positives discovered by PACS. We conclude that PACS is a useful modality for interpretation of body CT images.

Metastases from malignant melanoma to the axial skeleton: a CT study of frequency and appearance.

Radiologic detection of bone lesions from malignant melanoma is reported to be uncommon or infrequent. To ascertain the characteristics and frequency of detection of melanoma metastases to the axial skeleton by CT, we retrospectively reviewed 464 body CT studies of 125 consecutive melanoma patients for presence, appearance, and site of skeletal metastases. Results were correlated with patient's age, sex, clinical course, and both the Clark and Breslow classifications of the primary lesion. Of 98 patients with metastatic disease evident on their CT studies, 17 (17%) had bony metastases; two (12%) of these 17 patients had skeletal lesions as the only CT evidence of metastatic disease. Metastatic bony lesions were predominantly osteolytic, slightly expansile, and commonly located in the spine. Associated soft-tissue masses were frequent, but periosteal reaction and identifiable tumor matrix were not seen. Skeletal metastases were found only in those patients with thick or intermediate primary melanoma (Breslow) classified as Clark level III or greater, and the CT demonstration of osseous metastases was a poor prognostic sign. The data suggest that CT detection of skeletal melanoma metastases is not uncommon. When CT is performed to evaluate for metastatic melanoma, the axial skeleton should be carefully examined, especially in those patients with more advanced primary lesions.

Subcutaneous metastases from malignant melanoma: prevalence and findings on CT.

We reviewed 197 body CT studies on 53 sequential patients who had a histologic diagnosis of malignant melanoma in order to determine the CT appearance, pattern of spread, and prevalence of subcutaneous melanoma metastases. Seventeen (38%) of 45 patients with CT evidence of metastatic melanoma had subcutaneous nodules shown on CT. Five patients (11%) had subcutaneous nodules as the only indication of metastatic disease on their CT scans. All patients who developed subcutaneous metastases had primary lesions classified as Clark level IV or V. (The Clark classification is based on the depth of tumor invasion and is rated I to V.) Metastases appeared as small, discrete rounded densities in the subcutaneous fat; lesions were occasionally subtle because of their small size and peripheral location. The location of subcutaneous nodules could not be predicted consistently on the basis of the site of the primary malignancy. We conclude that subcutaneous metastases are common with melanoma in patients with Clark level IV or V lesions. These subcutaneous nodules are readily detected on CT scans if the subcutaneous tissues are carefully examined. The detection of these lesions may affect management or prognosis of patients, especially in those cases where subcutaneous nodules are the only CT evidence of metastatic disease.

Ultrafast Computed Tomography for Infants and Children

Experience using ultrafast CT in the diagnostic evaluation of more than 50 infants and children indicates that this new technique is highly accurate and easily performed. Ultrafast CT offers several advantages compared to conventional CT. Scan times of either 0.05 or 0.1 seconds were sufficiently short to eliminate motion artifacts, even without patient sedation; sedation is a routine procedure for the conventional CT examination of most infants and small children and carries a finite risk. Procedure time appears to be shorter using ultrafast CT, 15 minutes or less, than with conventional CT. No control data using conventional CT are available for this patient population, but generally pediatric body CT studies are scheduled at hourly intervals at our medical center and are rarely completed in less than 30 minutes. Dynamic imaging alternatives for evaluation of the pediatric heart and airway include angiocardiography, digital subtraction studies, and fluoroscopy, which are limited by relatively high radiation exposure and by the inability to display all wall motions simultaneously due to their projectional rather than tomographic orientation. The potential for acquiring serial 0.05-second images of rapidly moving structures, including the heart, airway, and lungs, is unique to the ultrafast CT technique and facilitates the identification of functional abnormalities, including intracardiac shunts, valvular obstructions, tracheomalacia, and segmental bronchial obstruction. The relationships of mediastinal soft tissue structures and vessels are well defined by both ultrafast and conventional CT. In situations in which fine spatial resolution is pivotally important, the radiologist has the option with the C-100 scanner to select the 0.1-second scanning mode. This mode results in a higher radiation exposure per slice, approximately two-fold, and also uses an array of more closely spaced detectors, 864, to increase dose efficiency and spatial resolution. Although not generally required for our pediatric patients, one has the additional option of performing repeated 0.1-second images at any level, as many as ten exposures, totaling 1.0 seconds, to increase photon flux and increase resolution. Thus, the choice of scanning options can markedly influence both radiation dose, resolution, and contrast sensitivity characteristics.