Standard dose versus low-dose abdominal and pelvic CT: Comparison between filtered back projection versus adaptive iterative dose reduction 3D

PurposeTo compare the dose and image quality of a standard dose abdominal and pelvic CT with Filtered Back Projection (FBP) to low-dose CT with Adaptive Iterative Dose Reduction 3D (AIDR 3D).Materials and methodsWe retrospectively examined the images of 21 patients in the portal phase of an abdominal and pelvic CT scan before and after implementation of AIDR 3D iterative reconstruction. The acquisition length, dose and evaluations of the image quality were compared between standard dose FBP images and low-dose images reconstructed with AIDR 3D and FBP using the Wilcoxon test.ResultsThe mean acquisition length was similar for both CT scans. There was a significant dose reduction of 49.5% with low-dose CT compared to standard dose CT (mean DLP of 451 mGy.cm versus 892 mGy.cm, P < 0.001). There were no differences in image quality scores between standard dose FBP and low-dose AIDR 3D images (4.6 ± 0.6 versus 4.4 ± 0.6 respectively, P = 0.147).ConclusionAIDR 3D iterative reconstruction enables a significant reduction in dose of 49.5% to be achieved with abdominal CT scan compared to FBP, whilst maintaining equivalent image quality.     

Automatic cervical lymphadenopathy segmentation from CT data using deep learning

PurposeThe purpose of this study was to develop a fast and automatic algorithm to detect and segment lymphadenopathy from head and neck computed tomography (CT) examination.Materials and methodsAn ensemble of three convolutional neural networks (CNNs) based on a U-Net architecture were trained to segment the lymphadenopathies in a fully supervised framework. The resulting predictions were assessed using the Dice similarity coefficient (DSC) on examinations presenting one or more adenopathies. On examinations without adenopathies, the score was given by the formula M/(M + A) where M was the mean adenopathy volume per patient and A the volume segmented by the algorithm. The networks were trained on 117 annotated CT acquisitions.ResultsThe test set included 150 additional CT acquisitions unseen during the training. The performance on the test set yielded a mean score of 0.63.ConclusionDespite limited available data and partial annotations, our CNN based approach achieved promising results in the task of cervical lymphadenopathy segmentation. It has the potential to bring precise quantification to the clinical workflow and to assist the clinician in the detection task.     

Differentiating autoimmune pancreatitis from pancreatic ductal adenocarcinoma with CT radiomics features

PurposeThe purpose of this study was to determine whether computed tomography (CT)-based machine learning of radiomics features could help distinguish autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).Materials and MethodsEighty-nine patients with AIP (65 men, 24 women; mean age, 59.7 ± 13.9 [SD] years; range: 21–83 years) and 93 patients with PDAC (68 men, 25 women; mean age, 60.1 ± 12.3 [SD] years; range: 36–86 years) were retrospectively included. All patients had dedicated dual-phase pancreatic protocol CT between 2004 and 2018. Thin-slice images (0.75/0.5 mm thickness/increment) were compared with thick-slices images (3 or 5 mm thickness/increment). Pancreatic regions involved by PDAC or AIP (areas of enlargement, altered enhancement, effacement of pancreatic duct) as well as uninvolved parenchyma were segmented as three-dimensional volumes. Four hundred and thirty-one radiomics features were extracted and a random forest was used to distinguish AIP from PDAC. CT data of 60 AIP and 60 PDAC patients were used for training and those of 29 AIP and 33 PDAC independent patients were used for testing.ResultsThe pancreas was diffusely involved in 37 (37/89; 41.6%) patients with AIP and not diffusely in 52 (52/89; 58.4%) patients. Using machine learning, 95.2% (59/62; 95% confidence interval [CI]: 89.8–100%), 83.9% (52:67; 95% CI: 74.7–93.0%) and 77.4% (48/62; 95% CI: 67.0–87.8%) of the 62 test patients were correctly classified as either having PDAC or AIP with thin-slice venous phase, thin-slice arterial phase, and thick-slice venous phase CT, respectively. Three of the 29 patients with AIP (3/29; 10.3%) were incorrectly classified as having PDAC but all 33 patients with PDAC (33/33; 100%) were correctly classified with thin-slice venous phase with 89.7% sensitivity (26/29; 95% CI: 78.6–100%) and 100% specificity (33/33; 95% CI: 93–100%) for the diagnosis of AIP, 95.2% accuracy (59/62; 95% CI: 89.8–100%) and area under the curve of 0.975 (95% CI: 0.936–1.0).ConclusionsRadiomic features help differentiate AIP from PDAC with an overall accuracy of 95.2%.     

Unenhanced CT for clinical triage of elderly patients presenting to the emergency department with acute abdominal pain

PurposeThe purpose of this study was to compare the diagnostic accuracy and inter-reader agreement of unenhanced computed tomography (CT) to those of contrast-enhanced CT for triage of patients older than 75 years admitted to emergency department (ED) with acute abdominal pain (AAP).Patients and methodsTwo hundred and eight consecutive patients presenting with AAP to the ED who underwent CT with unenhanced and contrast-enhanced images were retrospectively included. There were 90 men and 118 women with a mean age of 85.4 ± 4.9 (SD) (range: 75–101.4 years). Three readers reviewed unenhanced CT images first, and then unenhanced and contrast-enhanced CT images as a single set. Diagnostic accuracy was compared to the standard of reference defined as the final diagnosis obtained after complete clinico-biological and radiological evaluation. Correctness of the working diagnosis proposed by the ED physician was evaluated. Intra- and inter-reader agreements were calculated using the kappa test and interclass correlation. Subgroup analyses were performed for patients requiring only conservative management and for those requiring intervention.ResultsDiagnostic accuracy ranged from 64% (95% CI: 62–66%) to 68% (95% CI: 66–70%) for unenhanced CT, and from 68% (95% CI: 66–70%) to 71% (95% CI: 69–73%) for both unenhanced and contrast-enhanced CT. Contrast-enhanced CT did not significantly improve the diagnostic accuracy (P = 0.973–0.979). CT corrected the working diagnosis proposed by the ED physician in 59.1% (range: 58.1–60.0%) and 61.2% (range: 57.6–65.5%) of patients before and after contrast injection (P > 0.05). Intra-observer agreement was moderate to substantial (k = 0.513–0.711). Inter-reader agreement was substantial for unenhanced (kappa = 0.745–0.789) and combined unenhanced and contrast-enhanced CT (kappa = 0.745–0.799). Results were similar in subgroup analyses.ConclusionUnenhanced CT alone is accurate and associated with high degrees of inter-reader agreement for clinical triage of patients older than 75 years with AAP in the emergency setting.     

Diagnostic performance of ultra-low dose versus standard dose CT for non-traumatic abdominal emergencies

PurposeThe purpose of this study was to compare the diagnostic performance of ultra-low dose (ULD) to that of standard (STD) computed tomography (CT) for the diagnosis of non-traumatic abdominal emergencies using clinical follow-up as reference standard.Materials and methodsAll consecutive patients requiring emergency abdomen-pelvic CT examination from March 2017 to September 2017 were prospectively included. ULD and STD CTs were acquired after intravenous administration iodinated contrast medium (portal phase). CT acquisitions were performed at 125 mAs for STD and 55 mAs for ULD. Diagnostic performance was retrospectively evaluated on ULD and STD CTs using clinical follow-up as a reference diagnosis.ResultsA total of 308 CT examinations from 308 patients (145 men; mean age 59.1 ± 20.7 (SD) years; age range: 18–96 years) were included; among which 241/308 (78.2%) showed abnormal findings. The effective dose was significantly lower with the ULD protocol (1.55 ± 1.03 [SD] mSv) than with the STD (3.67 ± 2.56 [SD] mSv) (P < 0.001). Sensitivity was significantly lower for the ULD protocol (85.5% [95%CI: 80.4–89.4]) than for the STD (93.4% [95%CI: 89.4–95.9], P < 0.001) whereas specificities were similar (94.0% [95%CI: 85.1–98.0] vs. 95.5% [95%CI: 87.0–98.9], respectively). ULD sensitivity was equivalent to STD for bowel obstruction and colitis/diverticulitis (96.4% [95%CI: 87.0–99.6] and 86.5% [95%CI: 74.3–93.5] for ULD vs. 96.4% [95%CI: 87.0–99.6] and 88.5% [95%CI: 76.5–94.9] for STD, respectively) but lower for appendicitis, pyelonephritis, abscesses and renal colic (75.0% [95%CI: 57.6–86.9]; 77.3% [95%CI: 56.0–90.1]; 90.5% [95%CI: 69.6–98.4] and 85% [95%CI: 62.9–95.4] for ULD vs. 93.8% [95%CI: 78.6–99.2]; 95.5% [95%CI: 76.2–100.0]; 100.0% [95%CI: 81.4–100.0] and 100.0% [95%CI: 80.6–100.0] for STD, respectively). Sensitivities were significantly different between the two protocols only for appendicitis (P = 0.041).ConclusionIn an emergency context, for patients with non-traumatic abdominal emergencies, ULD-CT showed inferior diagnostic performance compared to STD-CT for most abdominal conditions except for bowel obstruction and colitis/diverticulitis detection.     

Effect of depth of neuromuscular blockade on the abdominal space during pneumoperitoneum establishment in laparoscopic surgery

Study ObjectiveTo evaluate the effect of neuromuscular blockade (NMB) upon the abdominal space during pneumoperitoneum establishment in laparoscopic surgery, comparing moderate NMB and deep NMB.DesignProspective, randomized, crossover clinical trial.SettingOperating room.PatientsSeventy-six American Society of Anesthesiologists 1 to 2 patients scheduled for elective laparoscopic surgery.InterventionsTwo independent evaluations were performed at the establishment of pneumoperitoneum for a preset intraabdominal pressures (IAPs) of 8 and 12 mm Hg, both during moderate NMB (train-of-four count, 1-3) and deep NMB (posttetanic count, < 5). Rocuronium was used to induce NMB, and sugammadex was used for reversal.MeasurementsWe evaluated (i) the volume of CO₂ introduced in 41 patients and (ii) the skin-sacral promontory distance in 35 patients, at pneumoperitoneum establishment.ResultsCompared to moderate NMB, deep NMB increased, in a significant manner, both the intraabdominal volume of CO₂ insufflated (mean [SD], 2.24 [1.10] vs 2.81 [1.13] L at 8 mm Hg IAP, P < .001, and 3.52 [1.31] vs 4.09 [1.31] L at 12 mm Hg IAP, P < .001) and the skin-sacral promontory distance (11.78 [1.52] vs 12.16 [1.51] cm at 8 mm Hg IAP, P = .002, and 13.34 [1.87] vs 13.80 [1.81] cm at 12 mm Hg IAP, P < .001). Increase in intraabdominal volume after inducing deep NMB was observed in 88% and 81.7% of patients at 8 and 12 mm Hg pneumoperitoneum, with a volume increase of mean of 36.8% (95% confidence interval [CI], 22.8-50.8) and 25% (95% CI, 13.7-36.4), respectively (P = .003). Increase in distance was observed in 61% and 82% of patients at 8 and 12 mm Hg pneumoperitoneum, with a mean distance increase of 3.3% (95% CI, 1.3-5.4) and 3.6% (95% CI, 1.9-5.2), respectively (P = .840).ConclusionsDeep NMB, in comparison to moderate NMB, increased in a significant manner the abdominal space at pneumoperitoneum establishment. However, the effective increase in the abdominal cavity dimensions could be low, the increase showed a great interindividual variability, and it was not observed in every patient. Clinical significance of this increase on surgical conditions is yet to be demonstrated.     

Metal artifact reduction for intracranial projectiles on post mortem computed tomography

PurposeTo compare the image quality of cranial post-mortem computed tomography (CT) obtained with and without projection-based single-energy metal artifact reduction (SEMAR) in cadavers with intracranial metallic ballistic projectiles.Materials and methodsFrom January 2017 to January 2018, cadavers with ballistic projectile head wounds with metal fragments and without massive head destruction were investigated using post-mortem CT. All subjects underwent CT using a conventional iterative reconstruction (IR) and SEMAR. To evaluate the impact of metallic artifacts, the total intracranial area (TA), non-interpretable zone (NIZ), disturbed interpretation zone (DZ), and artifact total surface (ATS) were delineated. Two independent readers identified extra-axial hemorrhage (EAH) and subarachnoid hemorrhage (SAH). Autopsy reports were used as the standard of reference.ResultsEleven corpses (10 males, 1 female; mean age, 62.8 ± 17.9 [SD] years) were evaluated. SEMAR showed a significant decrease in the ATS ratio with respect to conventional IR (72.1 ± 26.1 [SD] % [range: 26.8-99.1] vs. 86.4 ± 17.8 [SD] % [range: 37.2-100]; P < 0.001) and NIZ/TA ratios (11.6 ± 8.26% [range: 0.95–33.4] versus 42.5 ± 30.5% [range: 3.86–100]; P < 0.001). The interobserver reproducibility in diagnosing EAH and SAH was excellent with conventional IR (0.82) and good with SEMAR (0.75). SEMAR reduced uncertain diagnoses of EAH in 7 subjects for Reader 1 and in 6 for Reader 2, but did not influence the diagnosis of SAH for either reader.ConclusionSEMAR reduces the influence of metallic artifacts and increases the confidence with which the diagnosis of EAH can be made on post-mortem CT.     

Computed tomography follow-up of acute portal vein thrombosis

PurposeTo assess the evolution of acute portal vein thrombosis by computed tomography (CT).Patients and methodsRetrospective single-centre study (2005–2011) including 23 patients who had an initial CT scan and a CT scan during the first year. The analysis compared the last CT scan available with that of the initial CT scan. Neoplastic thrombosis, extrinsic compressions and cavernomas were excluded. All patients received anticoagulant treatment.ResultsThe causes included: cirrhoses (n = 6), blood disorders (n = 4), locoregional inflammations and infections (n = 8), abdominal surgery (n = 1). The thrombosis was idiopathic in 4 cases. After a mean follow-up of 7.7 months, 7 patients (30%) benefited from a restitutio ad integrum of the portal system, a stable or partially regressive thrombosis was noted in 12 patients (52%) and an aggravation of the thrombosis was noted in 4 patients (18%). In the sub-group of portal vein thrombosis, repermeabilisation was noted in 37.5% of the patients (6/16) and 6 cavernomas developed.ConclusionCT monitoring helps follow the evolution of an acute portal vein thrombosis and demonstrates complete repermeabilisation of the portal vein in 30% of the patients.     

Preoperative assessment of idiopathic scoliosis in adolescent and young adult with three-dimensional T2-weighted spin-echo MRI

PurposeTo compare tridimensional (3D) T2-weighted spin-echo MRI and CT for minimal pedicle width measurements in the preoperative assessment of adolescent idiopathic scoliosis (AIS) in adolescent and young patients.Materials and methodsA total of 22 adolescents/young patients suffering from AIS were retrospectively included. There were 18 females and 4 males with a mean age of 15.3 ± 2.3 (SD) years (range: 11–21 years). Preoperative lumbar spine MRI and CT examinations of the 22 patients were reviewed by two independent readers who measured the minimal width of 259 pedicles. Inter-reader agreement for CT and MRI was assessed using intra-class correlation coefficient (ICC). Intra-reader agreement and relative differences in measurements between MRI and CT were also assessed for each reader.ResultsInter-reader agreement was excellent (ICC ≥ 0.8) for both CT and MRI. Relative differences in measurements between CT and MRI was 10.3% for reader 1 and 9.4% for reader 2.Conclusion3D T2-weighted spin-echo MRI underestimates minimal pedicle width by only 9.4 - 10.3% compared to CT. 3D T2-weighted MRI appears as a valuable alternative to CT for preoperative measurements of vertebral pedicles in AIS.     

Detection of secondary causes of spontaneous pneumothorax: Comparison between computed tomography and chest X-ray

PurposeThe aim of this study was to compare the effectiveness of chest X-ray to that of thoracic computed tomography (CT) for the detection of the causes of secondary spontaneous pneumothorax (SP).MethodsA prospective cohort of patients with SP was studied. All chest X-ray and CT examinations of the patients were reviewed retrospectively by an expert radiologist blinded to clinical data. The concordance between the CT examination and chest X-ray was assessed using the Cohen Kappa coefficient (κ), based on a bootstrap resampling method.ResultsA total of 105 patients with SP were included. There were 78 men and 27 women, with a mean age of 34.5 years ± 14.2 (SD) (range: 16–87 years). Of these, 44/105 (41%) patients had primary SP and 61/105 (59%) had secondary SP due to emphysema (47/61; 77%), tuberculosis (3/61, 5%), lymphangioleiomyomatosis (3/61; 5%), lung cancer (2/61, 3%) or other causes (6/61; 10%). Apart from pneumothorax, CT showed abnormal findings in 85/105 (81%) patients and chest X-ray in 29/105 (28%). Clinically relevant abnormalities were detected on 62/105 (59%) CT examinations. The concordance between chest X-ray and CT was fair for detecting emphysema (κ = 0.39; 95% CI: 0.2420–0.55), moderate for a mass or nodule (κ = 0.60; 95% CI: 0.28–0.90), fair for alveolar opacities (κ = 0.39; 95% CI: −0.02–1.00), and slight for interstitial syndrome (κ = 0.20; 95% CI: −0.02–0.85).ConclusionChest X-ray is not sufficient for detecting the cause of secondary SP. As the detection of the cause of secondary SP may alter the therapeutic approach and long-term follow-up in patients with SP, the usefulness of a systematic CT examination should be assessed in a prospective trial.     

Is There a Benefit of Frequent CT Follow-up After EVAR?

ObjectiveImaging follow-up (FU) after endovascular aneurysm repair (EVAR) is usually performed by periodic contrast-enhanced computed tomography (CT) scans. This study aims to evaluate the effectiveness of CT-FU after EVAR.MethodsIn this study, 279 of 304 consecutive patients (261 male, aged 74 years (interquartile range (IQR): 70–79 years) with a median abdominal aortic aneurysm (AAA) diameter of 58 mm (IQR: 53–67 mm)) underwent at least one of the yearly CT scans and plain abdominal films after EVAR. All patients received Zenith stent-grafts for non-ruptured AAAs at a single institution. Patients were considered asymptomatic when a re-intervention was done solely due to an imaging FU finding. The data were prospectively entered in a computer database and retrospectively analysed.ResultsAs a follow-up, 1167 CT scans were performed at a median of 54 months (IQR: 34–74 months) after EVAR. Twenty-seven patients exhibited postoperative AAA expansion (a 5-year expansion-free rate of 88 ± 2%), and 57 patients underwent 78 postoperative re-interventions with a 5-year secondary success rate of 91 ± 2%. Of the 279 patients, 26 (9.3%) undergoing imaging FU benefitted from the yearly CT scans, since they had re-interventions based on asymptomatic imaging findings: AAA diameter expansion with or without endoleaks (n = 18), kink in the stent-graft limbs (n = 4), endoleak type III due to stent-graft limb separation without simultaneous AAA expansion (n = 2), isolated common iliac artery expansion (n = 1) and superior mesenteric artery malperfusion due to partial coverage by the stent-graft fabric (n = 1).ConclusionsLess than 10% of the patients benefit from the yearly CT-FU after EVAR. Only one re-intervention due to partial coverage of a branch by the stent-graft would have been delayed if routine FU had been based on simple diameter measurements and plain abdominal radiograph. This suggests that less-frequent CT is sufficient in the majority of patients, which may simplify the FU protocol, reduce radiation exposure and the total costs of EVAR. Contrast-enhanced CT scans continue, nevertheless, to be critical when re-interventions are planned.     

Comparison of perfused volume segmentation between cone-beam CT and 99mTc-MAA SPECT/CT for treatment dosimetry before selective internal radiation therapy using 90Y-glass microspheres

PurposeTo compare the reliability and accuracy of the pre-treatment dosimetry predictions using cone-beam computed tomography (CBCT) versus ^99mTc-labeled macroaggregated albumin (MAA) SPECT/CT for perfused volume segmentation in patients with hepatocellular carcinoma treated by selective internal radiation therapy (SIRT) using ⁹⁰Y-glass microspheres.Materials and methodsFifteen patients (8 men, 7 women) with a mean age of 68.3 ± 10.5 (SD) years (range: 47–82 years) who underwent a total of 17 SIRT procedures using ⁹⁰Y-glass microspheres for unresectable hepatocellular carcinoma were retrospectively included. Pre-treatment dosimetry data were calculated from ^99mTc-MAA SPECT/CT using either CBCT or ^99mTc-MAA SPECT/CT to segment the perfused volumes. Post-treatment dosimetry data were calculated using ⁹⁰Y imaging (SPECT/CT or PET/CT). The whole liver, non-tumoral liver, and tumor volumes were segmented on CT or MRI data. The mean absorbed doses of the tumor (D_T), non-tumoral liver, perfused liver (D_PL) and perfused non-tumoral liver were calculated. Intra- and interobserver reliabilities were investigated by calculating Lin's concordant correlation coefficients (ρ_c values). The differences (biases) between pre- and post-treatment dosimetry data were assessed using the modified Bland–Altman method (for non-normally distributed variables), and systematic bias was evaluated using Passing–Bablok regression.ResultsThe intra- and interobserver reliabilities were good-to-excellent (ρ_c: 0.80–0.99) for all measures using both methods. Compared with 90Y imaging, the median differences were 5.8 Gy (IQR: ?12.7; 16.1) and 5.6 Gy (IQR: ?13.6; 10.2) for D_PL-CBCT and D_PL-^99mTc-MAA SPECT/CT, respectively. The median differences were 1.6 Gy (IQR: ?29; 7.53) and 9.8 Gy (IQR: ?28.4; 19.9) for D_T-CBCT and D_T-^99mTc-MAA SPECT/CT respectively. Passing–Bablok regression analysis showed that both CBCT and ^99mTc-MAA SPECT/CT had proportional biases and thus tendencies to overestimate D_T and D_PL at higher post-treatment doses.ConclusionCBCT may be a reliable segmentation method, but it does not significantly increase the accuracy of dose prediction compared with that of ^99mTc-MAA SPECT/CT. At higher doses both methods tend to overestimate the doses to tumors and perfused livers.     

Performance of deep learning for differentiating pancreatic diseases on contrast-enhanced magnetic resonance imaging: A preliminary study

PurposeThe purpose of this study was to evaluate the ability of deep learning to differentiate pancreatic diseases on contrast-enhanced magnetic resonance (MR) images with the aid of generative adversarial network (GAN).Materials and MethodsA total of 504 patients who underwent T1-weighted contrast-enhanced MR examinations before any treatments were included in this retrospective study. First, the MRI examinations of 398 patients (215 men, 183 women; mean age, 59.14 ± 12.07 [SD] years [range: 16-85 years]) from one hospital were used as the training set. Then the MRI examinations of 50 (26 men, 24women; mean age, 58.58 ± 13.64 [SD] years [range: 24–85 years]) and 56 (30 men, 26 women; mean age, 59.13 ± 11.35 [SD] years [range: 26–80 years]) consecutive patients from two hospitals were separately collected as the internal and external validation sets. An InceptionV4 network was trained on the training set augmented by synthetic images from GANs. Classification performance of trained InceptionV4 network for every patch and every patient were made on both validation sets, respectively. The prediction agreement between convolutional neural network (CNN) and radiologist was measured by the Cohen's kappa coefficient.ResultsThe patch-level average accuracy and the micro-averaging area under receiver operating characteristic curve (AUC) of InceptionV4 network were 71.56% and 0.9204 (95% confidence interval [CI]: 0.9165–0.9308) for the internal validation set, and 79.46% and 0.9451 (95%CI: 0.9320–0.9523) for the external validation set, respectively. The patient-level average accuracy and the micro-averaging AUC of InceptionV4 network were 70.00% and 0.8250 (95%CI: 0.8147–0.8326) for the internal validation, 76.79% and 0.8646 (95%CI: 0.8489–0.8772) for the external validation set, respectively. Evaluated by human reader, the average accuracy and micro-averaging AUC for internal and external validation sets were 82.00% and 0.8950 (95%CI: 0.8817–0.9083), 83.93% and 0.9063 (95%CI: 0.8968–0.9212), respectively. The Cohen's kappa coefficients between InceptionV4 network and human reader for the internal and external invalidation sets were 0.8339 (95%CI: 0.6991–0.9447) and 0.8862 (95%CI: 0.7759–0.9738), respectively.ConclusionDeep learning using CNN and GAN had the potential to differentiate pancreatic diseases on contrast-enhanced MR images.     

Avoiding delayed diagnosis of significant blunt bowel and mesenteric injuries: Can a scoring tool make the difference? A 7-year retrospective cohort study

IntroductionSignificant blunt bowel and mesenteric injuries (sBBMI) are frequently missed despite the widespread use of computed tomography (CT). Early treatment improves the outcome related to these injuries. The aim of this study was to assess the prevalence of sBBMI, the incidence of delayed diagnosis and to test the performance of the Bowel Injury Prediction Score (BIPS), determined by the white blood cell (WBC) count, presence or absence of abdominal tenderness and CT grade of mesenteric injury.Patients and methodsSingle-centre, registry-based retrospective cohort study, screening all consecutive trauma patients admitted to Lausanne University Hospital Trauma Centre from 2008 to 2015 after a road traffic accident. All patients with reliable information about the presence or absence of sBBMI who underwent abdominal CT and for whom calculation of the BIPS was possible were included for analysis. The incidence of delayed (>24 h after admission) diagnosis in the patient group with sBBMI was determined and the diagnostic performance of the BIPS for sBBMI was assessed.ResultsFor analysis, 766 patients with reliable information about the presence or absence of sBBMI were included. The prevalence of sBBMI was 3.1% (24/766). In 24% (5/21) of stable trauma patients undergoing CT, a diagnostic delay of more than 24 h occurred. Abdominal tenderness (p < 0.0001) and CT grade ≥4 (p < 0.0001) were associated with sBBMI, whereas CT grade 4 alone (p = 0.93) and WBC count ≥17 G/l (p = 0.30) were not. A BIPS ≥2 had a sensitivity of 89% (95% CI, 67–99), specificity of 89% (95% CI, 86–91), positive likelihood ratio of 8 (95% CI, 6.1–10), negative likelihood ratio of 0.12 (95% CI, 0.03–0.44), positive predictive value (PPV) of 19% (95% CI, 15–24) and negative predictive value (NPV) of 99.7% (95% CI, 98.7–99.9). CT alone identified 79% (15/19) and the BIPS 89% (17/19) of patients with sBBMI (p = 0.66).ConclusionsDiagnostic delays in patients with sBBMI are common (24%), despite the routine use of abdominal CT. Application of the BIPS on the present cohort would have led to a high number of non-therapeutic abdominal explorations without identifying significantly more sBBMI early than CT alone.     

A snapshot of circulation failure following acute traumatic injury: The expansion of computed tomography beyond injury diagnosis

ObjectiveCT scans with a flat Inferior Vena Cava (IVC) suggest hypovolemia, and the presence of shock bowel implies hypoperfusion. The purpose of this study is to correlate injury severity, resuscitation needs, and clinical outcomes with CT indices of hypovolemia and hypoperfusion.DesignRetrospective cohort study.SettingLevel II trauma centre in Central California.PatientsAdult patients imaged with abdominal and pelvic CT scans, from January 2010–January 2011.InterventionsNone.Measurements and main resultsCirculatory derangements on CT scans were defined as an IVC (AP) diameter measurement of <9 mm, flat IVC (FIVC), hypovolemia. The presence of small intestine hypoperfusion was shock bowel (SB). The absence of these findings was a normal CT scan (NCT). Comparisons of acid-base status, fluids, morbidity and mortality were made based on CT findings. Subgroups were: FIVC (n = 20), FIVC + SB (n = 19), SB (n = 4) only versus normal CT scans, NCT (n = 47).ResultsOverall ISS was 19 (SD) 14. The lowest ISS was in NCT 14 (SD) 10 and there was an incremental increase in ISS based on circulatory derangements, p = 0.001. ICU admission was lowest in NCT and highest in the presence of hyovolemia and hypoperfusion, p = 0.03.Similarly ED crystalloid requirements and the activation of a massive transfusion protocol (MTP), was lowest in NCT group and gradually increased significantly as hypovolemia and hypoperfusion was demonstrated on CT scans. Additional parameters such as metabolic acidosis, nosocomial infections and mortality were associated with acute CT findings of circulatory failure.ConclusionsHypovolemia and hypoperfusion, markers of abnormal circulation, were demonstrated on CT scans for trauma evaluation. The presence of these findings alone or in combination showed strong correlation with high injury severity, and the need for aggressive resuscitation.     

Optimization of acquisition parameters for reduced-dose thoracic CT: A phantom study

PurposeThe purpose of this study was to analyze the impact of different options for reduced-dose computed tomography (CT) on image noise and visibility of pulmonary structures in order to define the best choice of parameters when performing ultra-low dose acquisitions of the chest in clinical routine.Materials and methodsUsing an anthropomorphic chest phantom, CT images were acquired at four defined low dose levels (computed tomography dose index [CTDI_vol] = 0.15, 0.20, 0.30 and 0.40 mGy), by changing tube voltage, pitch factor, or rotation time and adapting tube current to reach the predefined CTDI_vol-values. Images were reconstructed using two different levels of iteration (adaptive statistical iterative reconstruction [ASIR®]-v70% and ASIR®-v100%). Signal-to-noise ratio (SNR) as well as contrast-to-noise ratio (CNR) was calculated. Visibility of pulmonary structures (bronchi/vessels) were assessed by two readers on a 5-point-Likert scale.ResultsBest visual image assessments and CNR/SNR were obtained with high tube voltage, while lowest scores were reached with lower pitch factor followed by high tube current. Protocols favoring lower pitch factor resulted in decreased visibility of bronchi/vessels, especially in the periphery. Decreasing radiation dose from 0.40 to 0.30 mGy was not associated with a significant decrease in visual scores (P < 0.05), however decreasing radiation dose from 0.30 mGy to 0.15 mGy was associated with a lower visibility of most of the evaluated structures (P < 0.001). While image noise could be significantly reduced when ASIR®-v100% instead of ASIR®-v70% was used, the visibility-scores of pulmonary structures did not change significantly.ConclusionFavoring high tube voltage is the best option for reduced-dose protocols. A decrease of SNR and CNR does not necessarily go along with reduced visibility of pulmonary structures.     

Radiomics in the evaluation of lung nodules: Intrapatient concordance between full-dose and ultra-low-dose chest computed tomography

PurposeThe purpose of this study was to retrospectively evaluate the quantitative and qualitative intrapatient concordance of pulmonary nodule risk assessment by commercially available radiomics software between full-dose (FD) chest-CT and ultra-low-dose (ULD) chest CT.Materials and methodsBetween July 2013 and September 2015, 68 patients (52 men and16 women; mean age, 65.5 ± 10.6 [SD] years; range: 35–87 years) with lung nodules ≥ 5 mm and < 30 mm who underwent the same day FD chest CT (helical acquisition; 120 kV; automated tube current modulation) and ULD chest CT (helical acquisition; 135 kV; 10 mA fixed) were retrospectively included. Each nodule on each acquisition was assessed by a commercial radiomics software providing a similarity malignancy index (mSI), classifying it as “benign-like” (mSI < 0.1); “malignant-like” (mSI > 0.9) or “undetermined” (0.1 ≤ mSI ≤ 0.9). Intrapatient qualitative agreement was evaluated with weighted Cohen–Kappa test and quantitative agreement with intraclass correlation coefficient (ICC).ResultsNinety-nine lung nodules with a mean size of 9.14 ± 4.3 (SD) mm (range: 5–25 mm) in 68 patients (mean 1.46 nodule per patient; range: 1–5) were assessed; mean mSI was 0.429 ± 0.331 (SD) (range: 0.001–1) with FD chest CT (22/99 [22%] “benign-like”, 67/99 [68%] “undetermined” and 10/99 [10%] “malignant-like”) and mean mSI was 0.487 ± 0.344 (SD) (range: 0.002–1) with ULD chest CT (20/99 [20%] “benign-like”, 59/99 [60%] “undetermined” and 20/99 [20%] “malignant-like”). Qualitative and quantitative agreement of FD chest CT with ULD chest CT were “good” with Kappa value of 0.60 (95% CI: 0.46–0.74) and ICC of 0.82 (95% CI: 0.73–0.87), respectively.ConclusionA good agreement in malignancy similarity index can be obtained between ULD chest CT and FD chest CT using radiomics software. However, further studies must be done with more case material to confirm our results and elucidate the diagnostic capabilities of radiomics software using ULD chest CT for lung nodule characterization by comparison with FD chest CT.     

CT scan and Diagnostic Peritoneal Lavage: towards a better diagnosis in the area of nonoperative management of blunt abdominal trauma

BackgroundThe diagnosis of small bowel and mesenteric injuries (BBMI) after blunt abdominal trauma remains difficult, which results in delayed treatment and increased mortality and morbidity. Diagnostic peritoneal lavage (DPL) in patients with 1 or 2 abnormal CT findings that are suggestive of BBMI was proposed, but the rate of unnecessary surgical exploration remains high.Patients and methodsBlunt abdominal trauma patients with 1 or 2 CT findings predictive of BBMI from 2001 to 2014 underwent a DPL with calculation of a cell count ratio (CCR) dividing the ratio of white blood cells (WBCs) to red blood cells (RBCs) (WBC/RBC ratio) in the lavage fluid by the WBC/RBC ratio in peripheral blood. Surgical exploration of the abdomen was performed immediately in cases with a CCR ≥ 1. CT findings, DPL and surgery results, and global outcome were analyzed.ResultsThirty-seven were included in the study (27 males, median age of 30 years (range, 17–69 years)). Exploratory laparotomy was performed in 24 patients (65%). Sixteen patients (67%) had BBMI: 7 hollow organ perforations or tears (29%), including 4 bowel resection with primary anastomosis and 3 single sutures, and 9 patients had mesenteric injuries. CT findings associated with BBMI and hollow organ perforation were large peritoneal effusion (p = 0.02) and small bowel wall abnormalities (p = 0.002). No postoperative complications were observed. Sensitivity and specificity of DPL for the diagnosis of bowel injuries were respectively 100% (CI 95% [59–100]) and 43% (CI 95% [25–63]). The sensitivity remained 100% (CI 95% [59–100]) when the ratio was ≥4 (n = 10 patients), and the specificity reached 90% (CI 95% [73–98]).ConclusionDPL is sensitive for the diagnosis of BBMI in stable trauma patients with 1 or 2 unexplained CT abnormalities, but specificity is low with a high rate of nontherapeutic laparotomy in case of CCR ≥ 1. Indications for exploratory laparotomy could be restricted to patients with a CCR ≥ 4 to improve the specificity of diagnosis management.     

Results from more than 13,000 Weight-Bearing CT scans over 6.8 years. Impact on costs,radiation exposure and time spent

BackgroundThe purpose of this study was to assess the benefit of using Weight-Bearing CT (WBCT) instead of radiographs (R) and/or CT in a foot and ankle center regarding time spent for image acquisition, radiation dose, and cost effectiveness.Material and MethodsAll patients who obtained WBCT (PedCAT) from July 1, 2013 until March 15, 2020 were included in the study. Age, sex, primary pathology were analyzed. All parameters were compared between the time period using WBCT (yearly average) with the parameters from 2012, i.e. before availability of WBCT. The time spent for image acquisition (T) and radiation dose (RD) was calculated based on measured values from previous studies. For analysis cost effectiveness, device cost, reimbursement and working time cost of radiology technicians were taken into consideration within the local circumstances.Results13,156 WBCT scans were obtained in 5,798 patients (5,798 (44%) before treatment; 7,358 (56%) follow-up; mean age, 52.2; 46% male). Primary pathologies were forefoot deformities (n = 1,189 (21%) and ankle instability/cartilage defect (n = 832 (14%)), and hindfoot deformity (n = 765 (13%)). 1,935 WBCT scans were obtained on average yearly, and 10.2 CTs (WBCT group). In 2012, 1,850 R and 254 CTs were obtained (R(+CT) group). Yearly RD was 4.3 uSv for WBCT group and 4.8 uSv for R(+CT) group (difference 0.5 uSv decrease with WBCT 10%, p < 0.01). Yearly T was 113 hours in total (3.5 minutes per patient) for WBCT group and 493 hours in total (16.0 minutes per patient) for R(+CT) group (difference, 380 hours, decrease with WBCT, 77%, p < 0.01). Yearly profit was 53,543 Euro for WBCT group, -723 Euro for R(+CT) group.Conclusions13,156 WBCT scans in 5,798 patients as substitution of R(+CT) over a 6.8 year period at a foot and ankle center resulted in 10% decreased RD (minus 0.5 uSV on average per patient). Yearly T decreased 380 hours (77%) in total (12.0 minutes per patient). Yearly financial income increased more than 54,000 Euro in total (58 Euro per patient). RD decreased despite higher radiation dose for WBCT than for R alone, based on substitution of a high number of CTs by WBCT. Other centers with low usage of CT might not decrease RD by substituting R alone by WBCT.     

Application of an innovative computerized virtual planning system in acetabular fracture surgery: A feasibility study

IntroductionAcetabular fracture surgery is amongst the most challenging tasks in the field of trauma surgery and careful preoperative planning is crucial for success. The aim of this paper is to describe the preliminary outcome of the utilization of an innovative computerized virtual planning system for acetabular fractures.Methods3D models of acetabular fractures and surrounding soft tissues from six patients were constructed from preoperative CT scans. A novel highly-automatic segmentation technique was performed on the 3D model to separate each fracture fragment, then 3D virtual reduction was performed. Additionally, the models were used to assess potential surgical approaches with reference to both the fracture and the surrounding soft tissues. The time required for virtual planning was recorded. After surgery, the virtual plan was compared to the real surgery with respect to surgical approach and reduction sequence. A Likert scale questionnaire was completed by the surgeons to evaluate their satisfaction with the system.ResultsVirtual planning was successfully completed in all cases. The planned surgical approach was followed in all cases with the planned reduction sequence followed completely in five cases and partially in one. The mean time required for virtual planning was 38.7 min (range 21–57, SD = 15.5). The mean time required for planning of B-type fractures was 25.0 min (range 21–30, SD = 4.6), of C-type fracture 52.3 min (range 49–57, SD = 4.2). The results of the questionnaire demonstrated a high level of satisfaction with the planning system.ConclusionThis study demonstrates that the virtual planning system is feasible in clinical settings with high satisfaction and acceptability from the surgeons. It provides a viable option for the planning of acetabular fracture surgery.