Diagnostic performance of CT with Valsalva maneuver for the diagnosis and characterization of inguinal hernias

PURPOSE

Inguinal hernias are mainly diagnosed clinically, but imaging can aid in equivocal cases or for treatment planning. The purpose of this study was to evaluate the diagnostic performance of CT with Valsalva maneuver for the diagnosis and characterization of inguinal hernias.

METHODS

This single-center retrospective study reviewed all consecutive Valsalva-CT studies between 2018 and 2019. A composite clinical reference standard including surgery was used. Three blinded, independent readers (readers 1-3) reviewed the CT images and scored the presence and type of inguinal hernia. A fourth reader measured hernia size. Interreader agreement was quantified with Krippendorff's α coefficients. Sensitivity, specificity, and accuracy of Valsalva-CT for the detection of inguinal hernias was computed for each reader.

RESULTS

The final study population included 351 patients (99 women) with median age 52.2 years (interquartile range (IQR), 47.2, 68.9). A total of 381 inguinal hernias were present in 221 patients. Sensitivity, specificity, and accuracy were 85.8%, 98.1%, and 91.5% for reader 1, 72.7%, 92.5%, and 81.8% for reader 2, and 68.2%, 96.3%, and 81.1% for reader 3. Hernia neck size was significantly larger in cases correctly detected by all three readers (19.0 mm, IQR 13, 25), compared to those missed by all readers (7.0 mm, IQR, 5, 9; p < 0.001). Interreader agreement was substantial (α = 0.723) for the diagnosis of hernia and moderate (α = 0.522) for the type of hernia.

CONCLUSION

Valsalva-CT shows very high specificity and high accuracy for the diagnosis of inguinal hernia. Sensitivity is only moderate which is associated with missed smaller hernias.

Impact of myocardial injury on regional left ventricular function in the course of acute myocarditis with preserved ejection fraction: insights from segmental feature tracking strain analysis using cine cardiac MRI

The aim of this study was to provide insights into myocardial adaptation over time in myocyte injury caused by acute myocarditis with preserved ejection fraction. The effect of myocardial injury, as defined by the presence of late gadolinium enhancement (LGE), on the change of left ventricular (LV) segmental strain parameters was evaluated in a longitudinal analysis. Patients with a first episode of acute myocarditis were enrolled retrospectively. Peak radial (PRS), longitudinal (PLS) and circumferential (PCS) LV segmental strain values at baseline and at follow-up were computed using feature tracking cine cardiac magnetic resonance imaging. The change of segmental strain values in LGE positive (LGE+) and LGE negative (LGE-) segments was compared over a course of 89 ± 20 days. In 24 patients, 100 LGE+ segments and 284 LGE- segments were analysed. Between LGE+ and LGE- segments, significant differences were found for the change of segmental PCS (p < 0.001) and segmental PRS (p = 0.006). LGE + segments showed an increase in contractility, indicating recovery, and LGE- segments showed a decrease in contractility, indicating normalisation after a hypercontractile state or impairment of an initially normal contracting segment. No significant difference between LGE+ and LGE- segments was found for the change in segmental PLS. In the course of acute myocarditis with preserved ejection fraction, regional myocardial function adapts inversely in segments with and without LGE. As these effects seem to counterbalance each other, global functional parameters might be of limited use in monitoring functional recovery of these patients.

Prognostic factors in patients with acute mesenteric ischemia – a novel tool for determining patient outcomes

Objective

Acute mesenteric ischemia (MI) is a devastating disease with poor prognosis. Due to the multitude of underlying factors and broad clinical presentation, prediction of outcomes remains poor. Here, we aimed to identify factors governing survival in MI and develop a novel prognostic tool.

Methods

The present study is a monocentric retrospective analysis of patients with suspected MI undergoing imaging between January 2014 and December 2019. Primary endpoint was identification of factors influencing survival in patients undergoing surgery for confirmed MI, secondary endpoint was the development of a predictive nomogram to aid in determination of patient prognosis.

Results

539 patients underwent CT imaging for suspected MI, 216 of which had radiological indication of MI and 137 of those had subsequently confirmed MI. Factors associated with confirmed ischemia were increasing age, nausea/vomiting, history of peripheral arterial disease and presence of pneumatosis intestinalis and dilated bowel loops.

125 patients underwent surgery, 58 of which survived, and 67 died (median 9 days after diagnosis, IQR: 22). Baseline characteristics, including time from diagnosis to surgery were not different among patients, and outcomes were not affected by the presence of a surgical senior consultant or daytime of the operation. A minimally invasive approach was attempted more often in survivors (25.9% vs. 10.4%, p=0.024), however, in all but 1 patient (1.7%) conversion to open surgery was performed following detection of ischemia.

Increasing age and ASA score, type 2 diabetes, decreased haemoglobin and pH, increased creatinine, radiological atherosclerosis, vascular occlusion (versus non-occlusive MI) and affection of the colon (compared to small bowel ischemia only) were independently associated with impaired survival. Based on a multivariate model, we developed a nomogram for survival prediction, which showed adequate power upon internal validation (C-index = 0.738, Figure 1).

Conclusion

Acute MI remains a condition with high mortality. Here, we identified factors affecting survival after MI, namely colonic involvement, vascular co-morbidities and increasing age. Minimally invasive surgical approaches have not yet gained widespread acceptance in treatment of confirmed MI. Our novel nomogram might prove helpful in outcome prediction of patients with MI.

Tube voltage-independent coronary calcium scoring on a first-generation dual-source photon-counting CT-a proof-of-principle phantom study

To evaluate the accuracy of coronary artery calcium (CAC) scoring at various tube voltages and different monoenergetic image reconstructions on a first-generation dual-source photon-counting detector CT (PCD-CT). A commercially available anthropomorphic chest phantom with calcium inserts was scanned at different tube voltages (90 kV, Sn100kV, 120 kV, and Sn140kV) on a first-generation dual-source PCD-CT system with quantum technology using automatic exposure control with an image quality (IQ) level of 20. The same phantom was also scanned on a conventional energy-integrating detector CT (120 kV; weighted filtered back projection) for reference. Extension rings were used to emulate different patient sizes. Virtual monoenergetic images at 65 keV and 70 keV applying different levels of quantum iterative reconstruction (QIR) were reconstructed from the PCD-CT data sets. CAC scores were determined and compared to the reference. Radiation doses were noted. At an IQ level of 20, radiation doses ranged between 1.18 mGy and 4.64 mGy, depending on the tube voltage and phantom size. Imaging at 90 kV or Sn100kV was associated with a size-dependent radiation dose reduction between 23% and 48% compared to 120 kV. Tube voltage adapted image reconstructions with 65 keV and QIR 3 at 90 kV and with 70 keV and QIR 1 at Sn100kV allowed to calculate CAC scores comparable to conventional EID-CT scans with a percentage deviation of ≤ 5% for all phantom sizes. Our phantom study indicates that CAC scoring with dual-source PCD-CT is accurate at various tube voltages, offering the possibility of substantial radiation dose reduction.

Localization of ST-elevation on ECG is associated with regional myocardial fibrosis in acute myocarditis

Funding Acknowledgements

Type of funding sources: None.

Introduction

Both ST elevation (STE) on ECG and late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) are related to poor outcome in myocarditis.

Purpose

We evaluated if there is an association between regional STE and LGE pattern in patients with suspected myocarditis.

Methods

51 patients (42 male, 32 ± 13 years old) underwent 12-lead ECG and CMR with LGE due to suspected myocarditis. &gt;1mm STE was assessed in the antero-septal (V1-V4, aVR), inferior (II, III, aVF) and lateral (I, aVL, V5-V6) localizations. LGE was quantified as visual presence score (VPS) (1-17) and visual transmurality score (VTS) (1-68) on CMR, according to the 17-segment AHA model. STE and LGE were correlated using linear regression analysis. 

Results

31% of the patients had STE on admission ECG and a median VPS of 3 (IQR: 1-5) and VTS of 6 (IQR: 3-11) on CMR. STE showed an association with VPS and VTS in univariate and multivariate analysis (p &lt; 0.001 all). STE was most frequent in the lateral and inferior leads (48% and 31%) which correlated with regional VPS and VTS in univariate model (p &lt; 0.05 all), and remained significant in multivariate analysis for VPS (p &lt; 0.05 both). STE was less frequent in the antero-septal region (21%, where no association between LGE and STE could be revealed (p &gt; 0.05 all).

Conclusions

 Inferior and lateral STE in myocarditis is associated with regional LGE on CMR, which is an indicator of myocardial fibrosis and possible poor outcome. Our results need not be validated on larger cohorts with follow-up.

3D cardiac magnetic resonance stress-perfusion in elderly patients

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Swiss National Science Foundation

Introduction

Age related comorbidities and reduced compliance often limit ischaemia testing in elderly patients.

Purpose

To assessed the accuracy of 3D cardiac magnetic resonance (CMR) stress perfusion in the elderly population.

Methods

56 patients aged ≥75 years underwent 3D CMR stress-perfusion and invasive coronary angiography with quantitative coronary angiography (QCA) and fractional flow reserve (FFR) as part of a multicenter study. The accuracy of 3D CMR stress-perfusion was compared to patients aged &lt;75 years old (n = 360) using qualitative and quantitative imaging parameters.

Results

Sensitivity, specificity, positive and negative predictive values of qualitative 3D perfusion CMR were similar for both age groups in the detection of high-grade (≥50%) coronary stenosis on QCA and hemodynamically relevant (&lt;0.8) stenosis on FFR, p &gt; 0.05 all. Quantitative myocardial ischemia burden was larger in elderly patients (15% ± 17% vs. 9% ± 13%) with similarly high diagnostic accuracy of quantitative 3D CMR perfusion in both age groups to predict pathological FFR (AUC ≥75: 0.906; AUC &lt;75: 0.866).

Conclusions

3D CMR perfusion is well suited for myocardial ischaemia testing in the elderly patients with similarly high diagnostic accuracy as in younger individuals.

Value of cardiac magnetic resonance imaging derived spectral myocardial strain pattern for non-invasive diagnosis of myocarditis

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Society of Radiology European Institute for Biomedical Imaging Research

Background

Traditionally, cardiac function is quantified by measures of peak excursion, for example ejection fraction. However, myocardial strain estimation from cine- cardiac MRI allows quantification of cardiac motion over the whole heart cycle. We propose a spectral decomposition of the strain curves applying Discrete Fourier transformation (DFT).

Purpose

To evaluate a potential additive diagnostic value of spectral temporal strain curve quantification for non-invasive diagnosis of myocarditis using cardiac MRI.

Methods

In the single-center prospective study patients with suspected myocarditis underwent comprehensive cardiac MRI followed by biventricular endomyocardial biopsy (EMB) between 2012 and 2014. DFT was applied to myocardial strain curves extracted from cine-Images. As reference model, a L1- and L2-penalized logistic regression model using global native T1 time, T2 time and presence of late-gadolinium enhancement was trained to predict EMB results and compared to two models which additionally include three orders of DFT coefficients and ejection fraction, respectively. Predictive performance was evaluated in a tournament-leave-pair-out cross-validation approach with a bootstrap correction for testing of multiple hyperparameter configurations.

Results

Out of 100 patients (28 % female, median age 40 [IQR 32 to 56) years) with acute symptom-onset (&lt;30 days) 65 had pathologically proven myocarditis in EMB. The DFT model showed best discrimination (Area under the receiver-operating-curve [AUC] 0.72 [95% CI 52 to 87]). Addition of ejection fraction (AUC 0.60 [95% CI: 0.43 to 0.74]) did not increase AUC compared to the reference (AUC 0.60 [95% CI: 0.43 to 0.74]). Posterior distribution of the bootstrap-corrected AUC difference between DFT and reference model was gaussian (mean 12%, standard deviation 12%) with a posterior probability of 86%, that DFT has a greater AUC.

Conclusions

Discrimination of myocarditis from similar clinical presentations remains challenging. The results support incremental discriminatory value of DFT-decomposed myocardial strain for non-invasive diagnosis of myocarditis. Future research should address the value of the spectral decomposition of cardiac motion trajectories in larger samples and different disease entities.

Segmental strain analysis for the detection of chronic ischemic scars in non-contrast cardiac MRI cine images

Cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement (LGE) is considered the gold standard for scar detection after myocardial infarction. In times of increasing skepticism about gadolinium depositions in brain tissue and contraindications of gadolinium administration in some patient groups, tissue strain-based techniques for detecting ischemic scars should be further developed as part of clinical protocols. Therefore, the objective of the present work was to investigate whether segmental strain is noticeably affected in chronic infarcts and thus can be potentially used for infarct detection based on routinely acquired non-contrast cine images in patients with known coronary artery disease (CAD). Forty-six patients with known CAD and chronic scars in LGE images (5 female, mean age 52 ± 19 years) and 24 gender- and age-matched controls with normal cardiac MRI (2 female, mean age 47 ± 13 years) were retrospectively enrolled. Global (global peak circumferential [GPCS], global peak longitudinal [GPLS], global peak radial strain [GPRS]) and segmental (segmental peak circumferential [SPCS], segmental peak longitudinal [SPLS], segmental peak radial strain [SPRS]) strain parameters were calculated from standard non-contrast balanced SSFP cine sequences using commercially available software (Segment CMR, Medviso, Sweden). Visual wall motion assessment of short axis cine images as well as segmental circumferential strain calculations (endo-/epicardially contoured short axis cine and resulting polar plot strain map) of every patient and control were presented in random order to two independent blinded readers, which should localize potentially infarcted segments in those datasets blinded to LGE images and patient information. Global strain values were impaired in patients compared to controls (GPCS p = 0.02; GPLS p = 0.04; GPRS p = 0.01). Patients with preserved ejection fraction showed also impeded GPCS compared to healthy individuals (p = 0.04). In patients, mean SPCS was significantly impaired in subendocardially (-  5.4% ± 2) and in transmurally infarcted segments (- 1.2% ± 3) compared to remote myocardium (- 12.9% ± 3, p = 0.02 and 0.03, respectively). ROC analysis revealed an optimal cut-off value for SPCS for discriminating infarcted from remote myocardium of - 7.2% with a sensitivity of 89.4% and specificity of 85.7%. Mean SPRS was impeded in transmurally infarcted segments (15.9% ± 6) compared to SPRS of remote myocardium (31.4% ± 5; p = 0.02). The optimal cut-off value for SPRS for discriminating scar tissue from remote myocardium was 16.6% with a sensitivity of 83.3% and specificity of 76.5%. 80.3% of all in LGE infarcted segments (118/147) were correctly localized in segmental circumferential strain calculations based on non-contrast cine images compared to 53.7% (79/147) of infarcted segments detected by visual wall motion assessment (p > 0.01). Global strain parameters are impaired in patients with chronic infarcts compared to controls. Mean SPCS and SPRS in scar tissue is impeded compared to remote myocardium in infarcts patients. Blinded to LGE images, two readers correctly localized 80% of infarcted segments in segmental circumferential strain calculations based on non-contrast cine images, in contrast to only 54% of infarcted segments detected due to wall motion abnormalities in visual wall motion assessment. Analysis of segmental circumferential strain shows a promising method for detection of chronic scars in routinely acquired, non-contrast cine images for patients who cannot receive or decline gadolinium.

Mitral annular disjunction in patients with severe aortic stenosis: Extent and reproducibility of measurements with computed tomography

•

Mitral annulus disjunction (MAD) is frequent in patients with severe aortic stenosis.

•

Computed tomography enables a highly reproducible assessment of MAD.

•

MAD patients significantly more often have mitral valve prolapse.

Objectives

To determine with CT the prevalence and extent of mitral annular disjunction (MAD) in patients undergoing transcatheter aortic valve replacement (TAVR) and its association with mitral valve disease and arrhythmia.

Methods

We retrospectively evaluated 408 patients (median age, 82 years; 186 females) with severe aortic stenosis undergoing ECG-gated cardiac CT with end-systolic data acquisition. Baseline and follow-up data were collected in the context of a national registry. Two blinded, independent observers evaluated the presence of MAD on multi-planar reformations. Maximum MAD distance (left atrial wall-mitral leaflet junction to left ventricular myocardium) and circumferential extent of MAD were assessed on CT using dedicated post-processing software. Associated mitral valve disease was determined with echocardiography.

Results

7.8 % (32/408) of patients with severe aortic stenosis had MAD. The maximum MAD was 3.5 mm (interquartile range: 3.0–4.0 mm). The circumferential extent of MAD comprised 34 ± 15 % of the posterior and 26 ± 12 % of the entire mitral annulus. Intra- and interobserver agreement for the detection of MAD on CT were excellent (kappa: 0.90 ± 0.02 and 0.92 ± 0.02). Mitral regurgitation (p = 1.00) and severe mitral annular calcification (p = 0.29) were similarly prevalent in MAD and non-MAD patients. Significantly more patients with MAD (6/32; 19 %) had mitral valve prolapse compared to those without (6/376; 2 %; p < 0.001). MAD was not associated with arrhythmia before and after TAVR (p > 0.05).

Conclusions

Using CT, MAD was found in 7.8 % of patients with severe aortic stenosis, with a higher prevalence in patients with mitral valve prolapse. We found no association of MAD with arrhythmia before or after TAVR.

Mitral annular calcification in the elderly - Quantitative assessment

PURPOSE

To determine the reliability of subjective and objective quantification of mitral annular calcification (MAC) in elderly patients with severe aortic stenosis, to define quantitative sex- and age-related reference values of MAC, and to correlate quantitative MAC with mitral valve disease.

METHODS

In this retrospective, IRB-approved study, we included 559 patients (268 females, median age 81 years, inter-quartile range 77-85 years) with severe aortic stenosis undergoing CT. Four independent readers performed subjective MAC categorization as follows: no, mild, moderate, and severe MAC. Two independent readers performed quantitative evaluation of MAC using the Agatston score method (Agatston_MAC). Mitral valve disease was determined by echocardiography.

RESULTS

Subjective MAC categorization showed high inter-reader agreement for no (k ​= ​0.88) and severe MAC (k ​= ​0.75), whereas agreement for moderate (k ​= ​0.59) and mild (k ​= ​0.45) MAC was moderate. Intra-reader agreement for subjective MAC categorization was substantial (k ​= ​0.69 and 0.62). Inter- and intra-reader agreement for Agatston_MAC were excellent (ICC ​= ​0.998 and 0.999, respectively), with minor inconsistencies in MAC involving the left ventricular outflow tract/aortic valve. There were significantly more women than men with MAC (n ​= ​227, 85% versus n ​= ​209, 72%; p ​< ​0.001), with a significantly higher Agatston_MAC (median 597, range 81-2055 versus median 244; range 0-1565; p ​< ​0.001), particularly in patients ≥85 years of age. Agatston_MAC showed an area-under-the-curve of 0.84 to diagnose mitral stenosis, whereas there was no association of Agatston_MAC with mitral regurgitation (p ​> ​0.05).

CONCLUSIONS

Our study in elderly patients with severe aortic stenosis shows that quantitative MAC scoring is more reliable than subjective MAC assessment. Women show higher Agatston_MAC scores than men, particularly in the elderly population. Agatston_MAC shows high accuracy to diagnose mitral stenosis.

[Abdominal injuries in polytraumatized adults : Systematic review]

Abdominal injuries are potentially life-threatening and occur in 20-25% of all polytraumatized patients. Blunt trauma is the main mechanism. The liver and spleen are most commonly injured and much less often the intestines. The clinical evaluation proves equivocal in many cases; therefore, the gold standard is computed tomography (CT), which has been increasingly used even in hemodynamically weakly stable or sometimes even unstable patients because it promptly provides precise diagnostic findings, which present the basis for successful therapy. Hemodynamically unstable patients always need an exploratory laparotomy (EL). An EL should also be carried out with a positive focused assessment with sonography for trauma (FAST) or CT for severe parenchymal lesions, hollow organ lesions, intraperitoneal bladder lesions, peritonitis and organ evisceration, impalement injuries and lesions of the abdominal fascia. Hemodynamically stable patients without signs of peritonitis and a lack of such findings can often be treated conservatively irrespective of the extent of an injury. Angiography (and if needed embolization) can additionally be diagnostically and therapeutically utilized.

Prospective Randomized Comparison of High-pitch CT at 80 kVp Under Free Breathing with Standard-pitch CT at 100 kVp Under Breath-Hold for Detection of Pulmonary Embolism

RATIONALE AND OBJECTIVES

To prospectively compare high-pitch computed tomography (HPCT) under free breathing (FB) with standard-pitch CT (SPCT) under breath-hold (BH) for detection of pulmonary embolism (PE).

MATERIALS AND METHODS

One hundred consecutive patients (47 females; mean age 58.7 ± 16.6) randomly underwent HPCT-FB (n = 50) or SPCT-BH (n = 50). Radiation doses were documented. One reader measured pulmonary artery attenuation and noise; mean signal-to-noise ratio (SNR) was calculated. Two readers assessed image quality, diagnostic confidence for detection of PE, motion artifacts, assessability of anatomical structures, and presence of transient interruption of contrast as sign of Valsalva maneuver. Inter-reader agreement was calculated.

RESULTS

Radiation dose was significantly lower in HPCT compared to SPCT (2.68 ± 0.60 mGy vs 6.01 ± 2.26 mGy; P < .001). Mean pulmonary artery attenuation and image noise were significantly higher in HPCT (attenuation: 479 Hounsfield unit (HU) vs 343HU; P < .001; noise: 16 HU vs 10 HU; P < .001) whereas SNR was similar between groups (34 HU vs 38 HU; P = .258). HPCT had significantly higher diagnostic confidence for PE detection (P = .048), less cardiac and breathing artifacts (P < .001), better assessability of anatomical structures, and fewer cases of transient interruption of contrast (P < .001) compared to the SPCT.

CONCLUSIONS

HPCT-FB allows for a significant reduction of breathing and motion artifacts compared to SPCT-BH. Diagnostic confidence, assessability of vascular and bronchial structures, as well as SNR are maintained.

Automatic radiation dose monitoring for CT of trauma patients with different protocols: feasibility and accuracy

AIM

To demonstrate the feasibility and accuracy of automatic radiation dose monitoring software for computed tomography (CT) of trauma patients in a clinical setting over time, and to evaluate the potential of radiation dose reduction using iterative reconstruction (IR).

MATERIALS AND METHODS

In a time period of 18 months, data from 378 consecutive thoraco-abdominal CT examinations of trauma patients were extracted using automatic radiation dose monitoring software, and patients were split into three cohorts: cohort 1, 64-section CT with filtered back projection, 200 mAs tube current-time product; cohort 2, 128-section CT with IR and identical imaging protocol; cohort 3, 128-section CT with IR, 150 mAs tube current-time product. Radiation dose parameters from the software were compared with the individual patient protocols. Image noise was measured and image quality was semi-quantitatively determined.

RESULTS

Automatic extraction of radiation dose metrics was feasible and accurate in all (100%) patients. All CT examinations were of diagnostic quality. There were no differences between cohorts 1 and 2 regarding volume CT dose index (CTDIvol; p=0.62), dose-length product (DLP), and effective dose (ED, both p=0.95), while noise was significantly lower (chest and abdomen, both -38%, p<0.017). Compared to cohort 1, CTDIvol, DLP, and ED in cohort 3 were significantly lower (all -25%, p<0.017), similar to the noise in the chest (-32%) and abdomen (-27%, both p<0.017). Compared to cohort 2, CTDIvol (-28%), DLP, and ED (both -26%) in cohort 3 was significantly lower (all, p<0.017), while noise in the chest (+9%) and abdomen (+18%) was significantly higher (all, p<0.017).

CONCLUSION

Automatic radiation dose monitoring software is feasible and accurate, and can be implemented in a clinical setting for evaluating the effects of lowering radiation doses of CT protocols over time.

MR imaging features for improved diagnosis of hepatocellular carcinoma in the non-cirrhotic liver: Multi-center evaluation

PURPOSE

To determine MR-imaging features for the differentiation between hepatocellular carcinoma (HCC) and benign hepatocellular tumors in the non-cirrhotic liver.

MATERIAL AND METHODS

107 consecutive patients without liver cirrhosis (46 male; 45 ± 14 years) who underwent liver resection due to suspicion of HCC were included in this multi-center study. The following imaging features were assessed: lesion diameter and demarcation, satellite-lesions, central-scar, capsule, fat-content, hemorrhage, vein-infiltration and signal-intensity (SI) on native T1-, T2- and dynamic-enhanced T1-weighted images (center versus periphery). In addition, contrast-media (CM) uptake in the liver specific phase was analyzed in a sub-group of 42 patients.

RESULTS

Significant differences between HCC (n=55) and benign lesions (n=52) were shown for native T1-, T2- and dynamic-enhanced T1-SI, fat-content, and satellite-lesions (all, P<.05). Independent predictors for HCC were T1-hypointensity (odds-ratio, 4.81), T2-hypo-/hyperintensity (5.07), lack of central tumor-enhancement (3.36), and satellite-lesions (5.78; all P<0.05). Sensitivity and specificity of HCC was 91% and 75% respectively for two out-of four independent predictors, whereas specificity reached 98% for all four predictors. Sub-analysis, showed significant differences in liver specific CM uptake between HCC (n=18) and benign lesions (n=24; P<0.001) and revealed lack of liver specific CM uptake (odds-ratio, 2.7) as additional independent feature for diagnosis of HCC.

CONCLUSION

Independent MRI features indicating HCC are T1-hypointensity, T2-hypo- or hyperintensity, lack of central tumor-enhancement, presence of satellite-lesions and lack of liver specific CM-uptake. These features may have the potential to improve the diagnosis of HCC in the non-cirrhotic liver.

Whole-body CT-based imaging algorithm for multiple trauma patients: radiation dose and time to diagnosis

OBJECTIVE

To determine the number of imaging examinations, radiation dose and the time to complete trauma-related imaging in multiple trauma patients before and after introduction of whole-body CT (WBCT) into early trauma care.

METHODS

120 consecutive patients before and 120 patients after introduction of WBCT into the trauma algorithm of the University Hospital Zurich were compared regarding the number and type of CT, radiography, focused assessment with sonography for trauma (FAST), additional CT examinations (defined as CT of the same body regions after radiography and/or FAST) and the time to complete trauma-related imaging.

RESULTS

In the WBCT cohort, significantly more patients underwent CT of the head, neck, chest and abdomen (p < 0.001) than in the non-WBCT cohort, whereas the number of radiographic examinations of the cervical spine, chest and pelvis and of FAST examinations were significantly lower (p < 0.001). There were no significant differences between cohorts regarding the number of radiographic examinations of the upper (p = 0.56) and lower extremities (p = 0.30). We found significantly higher effective doses in the WBCT (29.5 mSv) than in the non-WBCT cohort (15.9 mSv; p < 0.001), but fewer additional CT examinations for completing the work-up were needed in the WBCT cohort (p < 0.001). The time to complete trauma-related imaging was significantly shorter in the WBCT (12 min) than in the non-WBCT cohort (75 min; p < 0.001).

CONCLUSION

Including WBCT in the initial work-up of trauma patients results in higher radiation doses, but fewer additional CT examinations are needed, and the time for completing trauma-related imaging is shorter.

ADVANCES IN KNOWLEDGE

WBCT in trauma patients is associated with a high radiation dose of 29.5 mSv.

Advanced modelled iterative reconstruction for abdominal CT: qualitative and quantitative evaluation

AIM

To determine qualitative and quantitative image-quality parameters in abdominal imaging using advanced modelled iterative reconstruction (ADMIRE) with third-generation dual-source 192 section CT.

MATERIALS AND METHODS

Forty patients undergoing abdominal portal-venous CT at different tube voltage levels (90, 100, 110, and 120 kVp, n = 10 each) and 10 consecutive patients undergoing abdominal non-enhanced low-dose CT (100 kVp, 60 mAs) using a third-generation dual-source 192 section CT machine in the single-source mode were included. Images were reconstructed with filtered back projection (FBP) and ADMIRE (strength levels 1-5). Two blinded, independent readers subjectively determined image noise, artefacts, visibility of small structures, and image contrast, and measured attenuation in the liver, spleen, kidney, muscle, fat, and urinary bladder, and objective image noise.

RESULTS

Subjective noise was significantly lower and image contrast significantly higher for each increasing ADMIRE strength level and also for ADMIRE 1 compared to FBP (all, p < 0.001). No significant differences were found for artefact and visibility ratings among image sets (all, p > 0.05). Attenuation was similar across tube voltage-image datasets in all anatomical regions (all, p > 0.05). Objective noise was significantly lower for each increasing ADMIRE strength level, and for ADMIRE 1 compared to FBP (all, p < 0.001, maximal reduction 53%). Independent predictors of noise were tube voltage (p < 0.05) and current (p < 0.001), diameter (p < 0.05), and reconstruction algorithm (p<0.001); the amount of noise reduction was related only to the reconstruction algorithm (p < 0.001).

CONCLUSION

Abdominal CT using ADMIRE results in an improved image quality with lower image noise as compared with FBP, while the attenuation of various anatomical regions remains constant among reconstruction algorithms.

[Epicardial fat: Imaging and implications for diseases of the cardiovascular system]

Since the discovery of the obese (ob) gene product leptin, fat has been considered an endocrine organ. Especially epicardial fat has gained increasing attention in recent years. The epicardial fat plays a major role in fat metabolism; however, harmful properties have also been reported. Echocardiography, computed tomography and cardiac magnetic resonance imaging are the non-invasive tools used to measure epicardial fat volume. This review briefly introduces the basic physiological and pathophysiological considerations concerning epicardial fat. The main issue of this review is the presentation of non-invasive measurement techniques of epicardial fat using various imaging modalities and a literature overview of associations between epicardial fat and common cardiovascular diseases.

[Investigation techniques and importance of CT for diagnostics of cardiac valvular diseases]

CLINICAL/METHODICAL ISSUE

Cardiac computed tomography (CT) is the first-line modality for coronary assessment. In addition valvular morphology and function can be evaluated.

STANDARD RADIOLOGICAL METHODS

The method of choice for the evaluation of cardiac valves is echocardiography, followed by magnetic resonance imaging.

METHODICAL INNOVATIONS

Recent technical improvements and advances in temporal resolution allow a detailed anatomical and functional evaluation of the cardiac valves.

PERFORMANCE

Cardiac CT provides an excellent image quality of the aortic and mitral valve thus enabling an evaluation of the morphology. In addition, cardiac CT allows an assessment of aortic valve function with respect to the grading of stenosis and regurgitation.

ACHIEVEMENTS

Cardiac CT is not considered the first-line modality for the evaluation of cardiac valves; however, beyond coronary assessment CT provides important information on the morphology and function of cardiac valves.

PRACTICAL RECOMMENDATIONS

Cardiac CT can be a useful imaging alternative for patients in whom other more commonly used methods, such as echocardiography and magnetic resonance imaging fail to provide the necessary information.

Low kilovoltage CT of the neck with 70 kVp: comparison with a standard protocol

BACKGROUND AND PURPOSE

CT protocols should aim for radiation doses being as low as reasonably achievable. The purpose of our study was to assess the image quality and radiation dose of neck CT at a tube potential of 70 kVp.

MATERIALS AND METHODS

Twenty patients (7 female, mean age 51.4 years, age range 19-81 years) underwent contrast-enhanced 64-section CT of the neck at 70 kVp (ATCM, effective tube current-time product 614 eff.mAs, range 467-713 eff.mAs). All 20 patients had a previous neck CT at 120 kVp on the same scanner. Two radiologists assessed image quality and artifacts in the upper, middle, and lower neck. Image noise and attenuation were measured, and the CNR was calculated. Effective radiation dose was calculated.

RESULTS

Interobserver agreement regarding image quality of soft tissue for 70-kVp and 120-kVp scans was good to excellent. At 70 kVp, soft tissues were of diagnostic image quality in all scans, whereas the lower cervical spine was not of diagnostic quality in 3 and 4 scans per both readers. No difference was found among 70-kVp and 120-kVp scans for soft tissue image quality in the upper neck, while image quality was significantly better in the middle at 70 kVp (P < .05) and better in the lower third at 120 kVp (P < .05). CNR was significantly higher at 70 kVp in all levels for both readers (P < .001). Effective radiation dose at 70 kVp was significantly lower (0.88 ± 0.2 mSv) than at 120 kVp (1.33 ± 0.2 mSv, P < .001).

CONCLUSIONS

CT of the cervical soft tissues at 70 kVp is feasible, provides diagnostic image quality with improved CNR, and reduces radiation dose by approximately 34% compared with a standard protocol at 120 kVp. In contrast, low kVp CT of the lower cervical spine suffers from compromised image quality.

Metallic artefact reduction with monoenergetic dual-energy CT: systematic ex vivo evaluation of posterior spinal fusion implants from various vendors and different spine levels

OBJECTIVES

To evaluate optimal monoenergetic dual-energy computed tomography (DECT) settings for artefact reduction of posterior spinal fusion implants of various vendors and spine levels.

METHODS

Posterior spinal fusion implants of five vendors for cervical, thoracic and lumbar spine were examined ex vivo with single-energy (SE) CT (120 kVp) and DECT (140/100 kVp). Extrapolated monoenergetic DECT images at 64, 69, 88, 105 keV and individually adjusted monoenergy for optimised image quality (OPTkeV) were generated. Two independent radiologists assessed quantitative and qualitative image parameters for each device and spine level.

RESULTS

Inter-reader agreements of quantitative and qualitative parameters were high (ICC = 0.81-1.00, κ = 0.54-0.77). HU values of spinal fusion implants were significantly different among vendors (P < 0.001), spine levels (P < 0.01) and among SECT, monoenergetic DECT of 64, 69, 88, 105 keV and OPTkeV (P < 0.01). Image quality was significantly (P < 0.001) different between datasets and improved with higher monoenergies of DECT compared with SECT (V = 0.58, P < 0.001). Artefacts decreased significantly (V = 0.51, P < 0.001) at higher monoenergies. OPTkeV values ranged from 123-141 keV. OPTkeV according to vendor and spine level are presented herein.

CONCLUSIONS

Monoenergetic DECT provides significantly better image quality and less metallic artefacts from implants than SECT. Use of individual keV values for vendor and spine level is recommended.

KEY POINTS

• Artefacts pose problems for CT following posterior spinal fusion implants. • CT images are interpreted better with monoenergetic extrapolation using dual-energy (DE) CT. • DECT extrapolation improves image quality and reduces metallic artefacts over SECT. • There were considerable differences in monoenergy values among vendors and spine levels. • Use of individualised monoenergy values is indicated for different metallic hardware devices.

Coronary computed tomography angiography indicates complexity of percutaneous coronary interventions

BACKGROUND

Coronary computed tomography angiography (CCTA) provides information regarding lesion morphology and three-dimensional coronary anatomy incremental to coronary angiography. We addressed the question whether preprocedural CCTA bears potential for guiding percutaneous coronary interventions (PCI).

METHODS AND RESULTS

Sixty-six coronary lesions attempted with PCI within 6 months of preprocedural CCTA were retrospectively assessed. Lesion parameters from unenhanced computed tomography (CT) for calcium scoring and CCTA were analyzed and compared with PCI complexity. Complex PCI was defined as use of buddy wire, kissing balloon, necessity of high pressure balloons, or rotablator. Complex PCIs were observed in 32 interventions (48%). Median Agatston score and Hounsfield units were higher in lesions with complex as compared to those with non-complex interventions with 130 (interquartile range, 23-276) vs 29 (0-158; P=.01), and 493 (245-631) vs 341 (68-520 Hounsfield Units; P=.04), respectively. Median local plaque volume and plaque mass were higher in complex PCI with 17 (2-39) vs 5 (0-19.5 mm³; P=.007), and 48 (15-99) vs. 16 (1.5-63 mg hydroxyapatite/mm³; P=.03), respectively. Lesions leading to complex PCI were longer [1.8 (1.2-2.8) vs 1.3 (0.8-1.7) cm; P=.03], and had a higher rate of calcified plaques (23% vs 3%; P=.03). There was a significant correlation between CCTA- and angiography-derived local SYNTAX Scores (P<.001); the CCTA-derived score seems to be predictive for failed and complex PCI (area under curve = 0.75 ± 0.13 and 0.66 ± 0.08, respectively).

CONCLUSIONS

Preprocedural lesion assessment by CCTA indicates complexity of PCI. In patients with suspected complex coronary anatomy, prior CCTA adds important information for planning PCI.

[Acute gastrointestinal bleeding - diagnosis with computed tomography]

Computed tomography represents a fast, non-invasive and accurate imaging modality for the diagnosis of acute gastrointestinal bleeding by providing information about localization and source of bleeding. Owing to its robustness and wide availability, it has the potential to be the first line imaging test in patients with acute life-threatening bleeding, for helping in the planning of interventional or surgical procedures.

[Computed tomography for imaging of pediatric congenital heart disease]

Congenital heart diseases are the most common congenital abnormalities of development. In general, echocardiography and cardiac catheter angiography are considered the gold standard for the evaluation of congenital heart disease. Cardiac magnetic resonance imaging has become an important supplementary imaging modality because of its ability to provide an accurate morphological and functional evaluation. The role of cardiac computed tomography in the imaging of patients with congenital heart disease is becoming increasingly more important due to the development of low radiation dose protocols and improvements in the spatial and temporal resolution. In the preoperative depiction and follow-up after surgical repair of congenital heart diseases, cardiac computed tomography provides detailed information of the heart, the venous and arterial pulmonary circulation as well as systemic arteries. This article reviews the technical aspects of cardiac CT and the modification of examination protocols according to the expected pathology and patient age. The potentials and limitations of the various radiation dose reduction strategies are outlined.

[Cardiac low-dose computed tomography]

Cardiac CT has evolved to a robust and accurate imaging modality in the cardiac diagnostic armamentarium. However, technical developments had been accompanied with an overall increase in radiation exposure. In the last years, several technical developments and algorithms aimed at the reduction of radiation exposure in cardiac CT. The most relevant dose reduction strategies will be highlighted in this article including appropriate indications for cardiac CT, different ECG synchronization techniques, reduction of tube voltage, and high-pitch CT studies.

[Use of multislice CT in the evaluation of patients with acute chest pain]

Acute chest pain is a common symptom but triage decisions in these patients remain a challenge. Patient's history, cardiac enzyme levels, or electrocardiograms often are unspecific. Nowadays, multidetector-row computed tomography (CT) currently represents the imaging modality of choice for diagnosing or excluding pulmonary embolism (PE) or acute aortic syndrome (AAS). Furthermore, recent studies have demonstrated advantages for non-invasive imaging of the coronary arteries by CT. The so called triple rule-out CT allows the depiction of the pulmonary arteries, the thoracic aorta, and the coronary arteries within a single examination with a simultaneous attenuation of these three vessel territories. This enables the detection of life-threatening such as PE, AAS and ACS, as well as of non-life-threatening diseases causing acute chest pain.

Multislice computed tomography coronary angiography for risk stratification in patients with an intermediate pretest likelihood

OBJECTIVES

To assess whether multislice computed tomography coronary angiography (MSCTA) may be useful for risk stratification of patients with suspected coronary artery disease (CAD) at intermediate pretest likelihood according to Diamond and Forrester.

DESIGN AND PATIENTS

MSCTA images were evaluated for the presence of significant CAD in 316 patients with suspected CAD (60% male, average (SD) age 57 (11) years) and an intermediate pretest likelihood according to Diamond and Forrester. Patients were followed up to determine the occurrence of an event.

MAIN OUTCOME MEASURES

A combined end point of all-cause mortality, non-fatal infarction and unstable angina requiring revascularisation.

RESULTS

Significant CAD was seen in 89 patients (28%), whereas normal MSCTA or non-significant CAD was seen in the remaining 227 (72%) patients. During follow-up (median 621 days (25-75th centile 408-835) an event occurred in 13 patients (4.8%). The annualised event rate was 0.8% in patients with normal MSCT, 2.2% in patients with non-significant CAD and 6.5% in patients with significant CAD. Moreover, MSCTA remained a significant predictor (p<0.05) of events after multivariate correction (hazard ratio = 3.460 (95% CI 1.142 to 10.480).

CONCLUSIONS

The results suggest that in patients with an intermediate pretest likelihood, MSCTA is highly effective in re-stratifying patients into either a low or high post-test risk group. These results further emphasise the usefulness of non-invasive imaging with MSCTA in this patient population.