Is there criteria to allow the selection of patients exposed to asbestos which is relevant to thoracic computed tomography screening?

OBJECTIVE: This study was undertaken to determine whether certain criteria could be used to select among asbestos-exposed subjects those who could benefit from computed tomography screening. MATERIALS AND METHODS: Search for criteria enabling the selection of patients who should undergo a CT screening exam after occupational exposure to asbestos was conducted in 150 subjects. All subjects were explored with selected high-resolution CT scans. Studied parameters were age, exposure data, pulmonary function test results. RESULTS: None of the exposure data or pulmonary function test results suggested with certainty the presence or absence of asbestos-related pleural and parenchymal lung disease. The studied parameters could not be used to select patients who could benefit from CT screening. CONCLUSION: None of the studied parameters enabled a selection of asbestos-exposed subjects who should undergo chest CT screening.     

White cell scanning for inflammatory bowel disease: are biochemical markers useful referral criteria?

The aim of this study was to determine whether biochemical markers for inflammation could prove effective in identifying the most appropriate patients with suspected inflammatory bowel disease (IBD) for labelled white cell scanning. One hundred and twenty-five patients referred for 99mTc-HMPAO labelled white cell scans were investigated. The values of C-reactive protein (CRP), antichymotrypsin (ACT) and acid glycoprotein (AGP) were measured in 73 patients, AGP and CRP in 10 and CRP only in a further 42. Sensitivity and specificity of each test were calculated using the white cell scan result as the 'gold standard'. ACT had the highest specificity (1.0), but the lowest sensitivity (0.27) of the three markers. CRP (using specified limits) had the lowest specificity (0.67) and the highest sensitivity (0.79). The corresponding values for AGP are 0.87 and 0.48. The low sensitivity of ACT and AGP preclude them from being useful referral criteria. CRP (using specified limits) is the most sensitive marker, but not sensitive enough to be useful as a referral indicator. However, by lowering the upper limit of normal to 5 mg.l-1, the sensitivity of the test increases to 0.96. Using this threshold to select the patients, 30% would not have been scanned and only one patient out of the 22 with IBD would have been missed. Where there is high demand for white cell scans this may provide a useful strategy for rationalizing the requests with minimal consequence on clinical management.     

Multidetector-row computed tomography diagnosis of small bowel obstruction: can coronal reformations replace axial images?

Feasibility of diagnosing small bowel obstruction on multidetector-row computed tomography (MDCT) using coronal reformations alone is evaluated. Three radiologists with subspecialty training in abdominal imaging reviewed abdominopelvic CT of 67 patients in consensus. Thirty-four patients had surgically proven small bowel obstruction. The remaining 33 patients had CT for other reasons and had no intestinal obstruction. The images were displayed in either axial or coronal planes and were reviewed on separate days . Each CT was evaluated for the presence of small bowel obstruction and its etiology when applicable. Thirty-three (100%) of 33 patients were correctly diagnosed not to have intestinal obstruction on coronal images. Thirty-four (100%) of 34 patients were correctly diagnosed to have small bowel obstruction on both forms of image display. There were five patients where the final surgical diagnosis for the etiology of small bowel obstruction did not agree with the interpretation of either the coronal or axial images; however, in all five patients, the interpretations of axial and coronal images were similar. In only one patient, the etiology of small bowel obstruction based on the coronal images did not agree with that of axial images and the surgical result; however, the site of small bowel obstruction was correctly diagnosed. There were approximately 20% fewer images in the coronal reformation data set, and the radiologists found review of these images to be easier for localizing the zone of transition in small bowel obstruction. Very high diagnostic accuracy can be achieved based on coronal reformations alone, and this form of image display may potentially be substituted for the conventional axial images. Since there are fewer images to review when the studies are displayed in coronal plane, this may positively impact radiologist workflow.     

Side-by-side reading of PET and CT scans in oncology: which patients might profit from integrated PET/CT?

Purpose Most early publications on integrated positron emission tomography/computed tomography (PET/CT) devices have reported the new scanner generation to be superior to conventional PET. However, few of these studies have analysed the situation where, in addition to PET, a current CT scan is available for side-by-side viewing. This fact is important, because combined PET/CT or a software-based fusion of the two modalities may improve diagnosis only in cases where side-by-side reading of PET and CT data does not lead to a definitive diagnosis. The aim of this study was to analyse which patients will profit from integrated PET/CT in terms of lesion characterization.Methods A total of 328 consecutively admitted patients referred for PET in whom a current CT scan was available were included in the study. The localization of all pathological PET lesions, as well as possible infiltration of adjacent anatomical structures, was assessed.Results Of 467 pathological lesions, 94.0% were correctly assessed with respect to localization and infiltration by either conventional PET alone (51.6%) or combined reading of PET and the already existing CT scans (42.4%). Hence, in only 6.0% of all lesions, affecting 6.7% of all patients, could evaluation have profited from integrated PET/CT.Conclusion We conclude that side-by-side viewing of PET and CT scans is essential, as in 42.4% of all cases, combined viewing was important for a correct diagnosis in our series. In up to 6.7% of patients, integrated PET/CT might have given additional information, so that in nearly 50% of patients some form of combined viewing of PET and CT data is needed for accurate lesion characterization.     

Dual-energy CT angiography of chronic thromboembolic disease: Can it help recognize links between the severity of pulmonary arterial obstruction and perfusion defects?

Purpose

To evaluate whether dual-energy CT angiography (DE-CTA) could identify links between morphologic and functional abnormalities in chronic pulmonary thromboembolism (CPTE).

Materials and methods

Seventeen consecutive patients with CPTE without underlying cardio-respiratory disease were investigated with DE-CTA. Two series of images were generated: (a) transverse diagnostic scans (i.e., contiguous 1-mm thick averaged images from both tubes), and (b) perfusion scans (i.e., images of the iodine content within the microcirculation; 4-mm thick MIPs). Two radiologists evaluated by consensus the presence of: (a) pulmonary vascular features of CPTE and abnormally dilated systemic arteries on diagnostic CT scans, and (b) perfusion defects of embolic type on perfusion scans.

Results

Diagnostic examinations showed a total of 166 pulmonary arteries (166/833; 19.9%) with features of CPTE, more frequent at the level of peripheral than central arteries (8.94 vs 0.82; p < 0.0001), including severe stenosis with partial (97/166; 58.4%) or complete (20/166; 12.0%) obstruction, webs and bands (37/166; 22.3%), partial filling defects without stenosis (7/166; 4.2%), focal stenosis (4/166; 2.4%) and abrupt vessel narrowing (1/166; 0.6%). Perfusion examinations showed 39 perfusion defects in 8 patients (median number: 4.9; range: 1-11). The most severe pulmonary arterial features of CPTE were seen with a significantly higher frequency in segments with perfusion defects than in segments with normal perfusion (p < 0.0001). Enlarged systemic arteries were observed with a significantly higher frequency ipsilateral to lungs with perfusion defects (9/12; 75%) compared with lungs without perfusion defects (5/22; 22.7%) (p = 0.004).

Conclusion

Dual-energy CTA demonstrates links between the severity of pulmonary arterial obstruction and perfusion impairment, influenced by the degree of development of the systemic collateral supply.     

Abdominal spiral CT in children: which radiation exposure is required?

We decided to test to what extent dose reduction is possible in abdominal spiral computed tomography (CT) in young children without loss of anatomic diagnostic information. A retrospective study was performed of 30 abdominal CT examinations of children aged 3 months to 7 years. These were divided into two groups: group A with reduced radiation exposure (tube current 50 mA, CT dose index CTDIFDA < or =0.83 mGy) and group B with standard radiation exposure (tube current > or =100 mA, CTDIFDA > or =1.66 mGy). Image quality was assessed using a four-part scale ('excellent', 'good', 'sufficient', 'poor') on visual image impression and visibility of 32 anatomical details. Five experienced radiologists read the CT scans independently who were blinded to the examination parameters. Differences in ranked data were evaluated with Wilcoxon's rank sum test. No difference between groups A and B was observed in visual image impression. Detail visibility was significantly lower in group A, but the differences were limited to right upper quadrant structures (portal vein, common bile duct, pancreatic head, adrenals) and to arterial branches. Significant differences in visibility rated as 'poor' were only found for the hepatic, splenic and renal arteries; all other structures showed no difference between groups A and B. A protocol with reduced radiation exposure (50 mA, CTDIFDA < or =0.83 mGy) allowed the demonstration of most anatomic structures in abdominal spiral CT in young children. For the precise demonstration of small details (e.g. structures of the right upper quadrant), a protocol with standard radiation exposure (> or =100 mAs) was superior.     

Creation of a Forensic Pathology Biobank in Switzerland: which issues and research opportunities?

A biobank is a collection of biological material associated with health database. The field of biobanking has significantly developed over the past 30 years. Research based on biobank material gives access to data of a large number of people and can often significantly accelerate the understanding of disease and improve the quality of care. In the University Center of Legal Medicine Lausanne-Geneva, samples collected during autopsies are used for forensic investigations. The legal and ethical framework to use these samples for research is often complex and confused, which is unfortunate given the potential of these biospecimens. Indeed, forensic samples are valuable for research because they originate in part from young (including pediatrics cases) and healthy people who are poorly represented in worldwide institutional biobanks. In this context at the beginning of the year 2019, the Forensic Pathology Biobank was created. Creation of a forensic pathology biobank is the best way to standardize local conservation practices and improve personal data management, thus providing a very valuable biological material for scientific projects. Its development gives rise to many questions about technical standards, ethical and legal issues but also many research opportunities.

     

CT criteria for differentiating abdominal hemorrhage: anticoagulation or aortic aneurysm rupture?

OBJECTIVE: The purpose of our study was to test the hypothesis that CT criteria would allow accurate diagnosis of the specific cause of abdominal hemorrhage in patients with coagulopathy or abdominal aortic aneurysm. CONCLUSION: Attention to specific CT criteria allows accurate diagnosis of the specific cause of spontaneous abdominal hemorrhage even in patients who have both coagulopathy and an abdominal aortic aneurysm.     

Pseudomembranous colitis: can CT predict which patients will need surgical intervention?

PURPOSE: Our purpose was to determine if patients with pseudomembranous colitis (PMC) requiring surgical intervention demonstrate radiographic features distinct from those of patients treated successfully with standard medical therapy. METHOD: The indications for a CT study and the imaging findings from 17 patients who required laparotomy with colon resection for PMC were retrospectively reviewed. The CT findings were compared with the findings from 17 control patients (matched by clinical presentation) with PMC who were treated medically and did not require surgical intervention. RESULTS: None of the CT findings evaluated in this study were significantly different between the surgical and nonsurgical groups. The CT findings evaluated for the surgical and nonsurgical groups, respectively, were as follows: wall thickness of the colon: 17.8+/-6.6 and 16.9+/-3.9 mm; largest caliber of the colon: 6.8+/-1.6 and 6.1+/-1.2 cm; presence of the accordion sign: 52.9 and 70.6%; heterogeneous contrast enhancement pattern (target sign): 57.1 and 57.1%; pericolonic stranding: 82.4 and 88.2%; ascites: 70.6 and 58.8%; pleural effusion(s): 64.7 and 64.7%; and subcutaneous edema: 64.7 and 64.7%. CONCLUSION: Although none of the CT findings evaluated in this study was significantly different between the surgical and nonsurgical groups, CT was often the initial diagnostic modality in both groups. It is important for radiologists to recognize the CT appearance of PMC and suggest the diagnosis. However, patient triage may not be based solely on the CT findings.     

Small bowel MRI imaging in the DGH — Are you doing it yet?

The aim of this article is to illustrate the spectrum of disease visualized at small bowel magnetic resonance imaging (MRI) in the district general hospital (DGH) setting. The advantages and disadvantages of small bowel MRI, technique, and service implementation are discussed.     

Imaging of small bowel Crohn's disease: can abdominal CT replace barium radiography?

Objectives: To analyze imaging features and compare the diagnostic information provided by abdominal computed tomography (CT) and enteroclysis to see whether CT can replace barium examinations in the assessment of patients with small bowel Crohn's disease. Methods: The abdominal CT studies and enteroclysis of 33 patients with small bowel Crohn's disease who underwent both examinations within a 2-week time period were retrospectively reviewed and scored for the presence and severity of the following features: mural edema, ulceration, small bowel obstruction, stricture, sinus tract formation, fistula, abscess, extraintestinal manifestations, and total number of intestinal sites involved. The statistical significance of the differences for each variable was calculated. Results: A total of 37 case sets were reviewed. CT demonstrated 10 (27 %) abscesses compared to 7 (19 %) shown by enteroclysis. Three extraintestinal sites shown by CT were not demonstrated by enteroclysis. Enteroclysis detected a larger number of intestinal sites of involvement (54 vs. 47) and more cases of ulceration (78 % vs. 19 %), small bowel obstruction (46 % vs. 16 %), stricture (38 % vs. 11 %), fistula formation (24 % vs. 8 %), and sinus tract formation (27 % vs. 5 %). The two modalities were similar in characterizing and grading the severity of mural thickening (CT showed 41 %, enteroclysis 46 %). Conclusion: Abdominal CT and enteroclysis provide unique and complementary diagnostic information in patients with Crohn's disease of the small bowel. Both methods may be required for the accurate assessment of the severity and extent of Crohn's disease of the small bowel. The choice of initial examination will depend on the clinical issue in question.     

ASER Core Curriculum Illustration Project—Volvulus: a rare cause of small bowel obstruction

This is the ninth installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.aseronline.org/curriculum/toc.htm.