Dual-source CT coronary angiography: prospective versus retrospective acquisition technique

Purpose

The aim of our work was to compare image quality and radiation dose in a group of patients who underwent cardiac dual-source computed tomography (DSCT) with prospective electrocardiographic (ECG) gating with those of a control group studied with retrospective gating.

Materials and methods

Sixty patients were randomly assigned to two groups of 30 individuals each. Patients with heart rates >70 bpm and body mass index (BMI) >30 kg/m² were excluded. Group A was examined with prospective ECG gating and group B with retrospective gating. The dose-length product (DLP) was recorded to calculate the radiation dose, whereas the effective dose was normalised to a standard 12-cm scan of the heart.

Results

Applying the best reconstruction interval, 98.6% of segments in the prospective group and 99.3% in the retrospective group were diagnostic. No significant difference (p>0.05) in image quality was observed between groups. Mean normalised radiation dose was 4.91±0.4 mSv in the prospective-gating group and 14.62 mSv±4.36 in the retrospective-gating group (p<0.01).

Conclusions

Coronary CT with prospective ECG gating, a standard feature on new scanners, allows for a significant reduction in radiation dose without causing any significant decrease in image quality or in the number of segments assessed. The prospective technique is thus recommended for patients with heart rates £70 bpm and BMI £30 kg/m².     

Performance of turbo high-pitch dual-source CT for coronary CT angiography: first ex vivo and patient experience

Objectives

To evaluate image quality, maximal heart rate allowing for diagnostic imaging, and radiation dose of turbo high-pitch dual-source coronary computed tomographic angiography (CCTA).

Methods

First, a cardiac motion phantom simulating heart rates (HRs) from 60-90 bpm in 5-bpm steps was examined on a third-generation dual-source 192-slice CT (prospective ECG-triggering, pitch 3.2; rotation time, 250 ms). Subjective image quality regarding the presence of motion artefacts was interpreted by two readers on a four-point scale (1, excellent; 4, non-diagnostic). Objective image quality was assessed by calculating distortion vectors. Thereafter, 20 consecutive patients (median, 50 years) undergoing clinically indicated CCTA were included.

Results

In the phantom study, image quality was rated diagnostic up to the HR75 bpm, with object distortion being 1 mm or less. Distortion increased above 1 mm at HR of 80-90 bpm. Patients had a mean HR of 66 bpm (47-78 bpm). Coronary segments were of diagnostic image quality for all patients with HR up to 73 bpm. Average effective radiation dose in patients was 0.6?±?0.3 mSv.

Conclusions

Our combined phantom and patient study indicates that CCTA with turbo high-pitch third-generation dual-source 192-slice CT can be performed at HR up to 75 bpm while maintaining diagnostic image quality, being associated with an average radiation dose of 0.6 mSv.

Key points

? CCTA is feasible with the turbo high-pitch mode. ? Turbo high-pitch CCTA provides diagnostic image quality up to 73 bpm. ? The radiation dose of high-pitch CCTA is 0.6 mSv on average.     

Diagnostic accuracy of coronary CT angiography using 3<Superscript>rd</Superscript>-generation dual-source CT and automated tube voltage selection: Clinical application in a non-obese and obese patient population

Purpose

To investigate diagnostic accuracy of 3^rd-generation dual-source CT (DSCT) coronary angiography in obese and non-obese patients.

Methods

We retrospectively analyzed 76 patients who underwent coronary CT angiography (CCTA) and invasive coronary angiography. Prospectively ECG-triggered acquisition was performed with automated tube voltage selection (ATVS). Patients were dichotomized based on body mass index in groups A (<30 kg/m², n?=?37) and B (≥30 kg/m², n?=?39) and based on tube voltage in groups C (<120 kV, n?=?46) and D (120 kV, n?=?30). Coronary arteries were assessed for significant stenoses (≥50 % luminal narrowing) and diagnostic accuracy was calculated.

Results

Per-patient overall sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy were 96.9 %, 95.5 %, 93.9 %, 97.7 % and 96.1 %, respectively. Sensitivity and NPV were lower in groups B and D compared to groups A and C, but no statistically significant differences were observed (group A vs. B: sensitivity, 100.0 % vs. 93.3 %, p?=?0.9493; NPV, 100 % vs. 95.5 %, p?=?0.9812; group C vs. D: sensitivity, 100.0 % vs. 92.3 %, p?=?0.8462; NPV, 100.0 % vs. 94.1 %, p?=?0.8285).

Conclusion

CCTA using 3^rd-generation DSCT and (ATVS) provides high diagnostic accuracy in both non-obese and obese patients.

Key Points

? Coronary CTA provides high diagnostic accuracy in non-obese and obese patients. ? Diagnostic accuracy between obese and non-obese patients showed no significant difference.? <120 kV studies were performed in 44 % of obese patients. ? Current radiation dose-saving approaches can be applied independent of body habitus.

     

Prospectively ECG-triggered sequential dual-source coronary CT angiography in patients with atrial fibrillation: comparison with retrospectively ECG-gated helical CT

Objective

To investigate the feasibility of applying prospectively ECG-triggered sequential coronary CT angiography (CCTA) to patients with atrial fibrillation (AF) and evaluate the image quality and radiation dose compared with a retrospectively ECG-gated helical protocol.

Methods

100 patients with persistent AF were enrolled. Fifty patients were randomly assigned to a prospective protocol and the other patients to a retrospective protocol using a second-generation dual-source CT (DS-CT). Image quality was evaluated using a four-point grading scale (1 = excellent, 2 = good, 3 = moderate, 4 = poor) by two reviewers on a per-segment basis. The coronary artery segments were considered non-diagnostic with a quality score of 4. The radiation dose was evaluated.

Results

Diagnostic segment rate in the prospective group was 99.4 % (642/646 segments), while that in the retrospective group was 96.5 % (604/626 segments) (P?<?0.001). Effective dose was 4.29?±?1.86 and 11.95?±?5.34 mSv for each of the two protocols (P?<?0.001), which was a 64 % reduction in the radiation dose for prospective sequential imaging compared with retrospective helical imaging.

Conclusion

In AF patients, prospectively ECG-triggered sequential CCTA is feasible using second-generation DS-CT and can decrease >60 % radiation exposure compared with retrospectively ECG-gated helical imaging while improving diagnostic image quality.

Key Points

? Coronary computed tomographic angiography (CCTA) can be difficult in patients with arrhythmias. ? Prospectively ECG-triggered sequential CCTA is feasible in patients with atrial fibrillation. ? Prospective sequential imaging can improve quality compared with retrospective analysis. ? Prospective sequential imaging decreases radiation exposure by 64 % compared with retrospective mode.     

Helical CT-enteroclysis in the detection of small-bowel tumours: a meta-analysis

Objective

To perform a meta-analysis to determine sensitivity and specificity estimates of helical CT-enteroclysis in the detection of small-bowel tumours.

Methods

A search for relevant articles published from January 1992 to November 2010 was performed. Study design, patient characteristics and 2?×?2 contingency tables were recorded for eligible studies. Heterogeneity was assessed with the I ² statistic. A bivariate generalised linear random-effects model was used to summarise sensitivity and specificity estimates for small-bowel tumour detection on a per-patient basis. Sensitivity and specificity estimates were compared in different subgroups.

Results

Twelve studies (696 patients) were eligible. The mean small-bowel tumour prevalence was 22.6 % (range 7.7–45.8 %). Inter-study heterogeneity was substantial for sensitivity (I ²?=?66.9 %; 95 % CI 28.7–88.5 %) and low for specificity (I ²?=?10.6 %; 95 % CI 0.0–55.0 %). On a per-patient basis, pooled sensitivity was 92.8 % (95 % CI 71.3–98.5 %) and pooled specificity 99.2 % (95 % CI 94.2–99.9 %) for the diagnosis of small-bowel tumour. Subgroup analysis revealed that small-bowel preparation, more than one imaging pass and large volumes (≥2 L) of enteral contrast agent did not improve tumour detection.

Conclusion

Our meta-analysis confirms that helical CT-enteroclysis has high degrees of sensitivity and specificity for small-bowel tumour detection. However, our findings reinforce the need for more standardised individual studies.

Key Points

? Helical CT-enteroclysis is highly sensitive for the diagnosis of small-bowel tumours. ? Helical CT-enteroclysis is highly specific for the diagnosis of small-bowel tumours, ? Helical CT-enteroclysis can be used as a first-line investigation. ? A single enteric phase examination provides optimal tumour detection.     

Ultrasound as a diagnostic tool in detecting active Crohn’s disease: a meta-analysis of prospective studies

Objectives

To evaluate the diagnostic accuracy of ultrasound in assessing active Crohn’s disease (CD) in adults.

Methods

We systematically searched PubMed, EMBASE, Web of Science and the Cochrane Library for prospective studies in which ultrasound was performed to evaluate active CD in adults from January 1993 to April 2013. Pooled sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR?) and diagnostic odds ratios (DORs) in a per-patient-based analysis were estimated. Additionally, the area under the receiver-operating characteristic (ROC) curve was calculated to measure the diagnostic accuracy of ultrasound in patients with known or suspected CD.

Results

Fifteen studies involving 1,558 patients were included in this meta-analysis. Overall, the pooled sensitivity (0.88) and LR- (0.14) were not heterogeneous, whereas the pooled specificity (0.97, I²?=?72.9 %) and LR?+?(15.10, I²?=?71.8 %) were. The DOR of ultrasound for assessing active CD was 121.70, with significant heterogeneity (I²?=?63.3 %). A symmetrical summary ROC curve was plotted showing that the area under the curve was 0.94, indicating good diagnostic accuracy. Meta-regression and subgroup analysis showed that the disease location may be a major cause of heterogeneity.

Conclusions

This meta-analysis suggests that ultrasound has high diagnostic accuracy in detecting active CD in adults, especially for small bowel CD.

Key Points

? Ultrasound can detect active Crohn’s disease (CD). ? A meta-analysis of ultrasound for detecting active CD was carried out. ? This revealed that ultrasound has high diagnostic accuracy for detecting CD.     

Comparative diagnostic accuracy of contrast-enhanced MRI and 18F-FDOPA PET-CT in recurrent glioma

Objectives

To compare the diagnostic accuracy of contrast enhanced magnetic resonance imaging (Ce-MRI) and ¹⁸F-fluorodopa (¹⁸F-FDOPA) positron emission tomography (PET)-computed tomography (CT) for detecting recurrent glioma.

Methods

In this prospective study, 35 patients (age, 36.62?±?0.86 years; 80 % male) with histopathologically proven glioma with clinical suspicion of recurrence were evaluated using Ce-MRI and ¹⁸F-FDOPA PET-CT. ¹⁸F-FDOPA PET-CT images were evaluated qualitatively and semi-quantitatively. Combination of clinical follow-up (minimum 1 year), repeat imaging and/or biopsy (when available) was taken as the reference standard.

Results

Based on the reference standard, 26 patients were positive and nine were negative for recurrence. The sensitivity, specificity and accuracy of Ce-MRI were 92.3 %, 44.4 % and 80 % respectively, whereas those of ¹⁸F-FDOPA PET-CT were 100 %, 88.89 % and 97.1 % respectively. Results of Ce-MRI and ¹⁸F-FDOPA PET-CT were concordant in 74.3 % (29/35) and discordant in 17.1 % of patients (6/35). On McNemar analysis the difference was not statistically significant overall (P?=?0.687), for high-grade tumour (P?=?0.5) or low-grade tumours (P?=?1.0). However, ¹⁸F-FDOPA PET-CT was more specific than Ce-MRI overall (P?=?0.0002), for high-grade tumour (P?=?0.006) and low-grade tumours (P?=?0.004).

Conclusion

F-FDOPA PET-CT shows a high but comparable diagnostic accuracy to Ce-MRI for the detection of recurrent glioma. However, it is more specific than Ce-MRI.

Key Points

? Recurrent glioma in the postoperative site remains a diagnostic dilemma. ? ¹⁸ F-FDOPA PET-CT shows high diagnostic accuracy for detecting recurrent glioma. ? Diagnostic accuracies for ¹⁸ F-FDOPA PET-CT and contrast enhanced MRI are comparable. ? However, ¹⁸ F-FDOPA PET-CT is more specific than Ce-MRI for recurrent glioma.     

Feasibility of prospectively ECG-triggered high-pitch coronary CT angiography with 30 mL iodinated contrast agent at 70 kVp: initial experience

Objectives

To evaluate the feasibility, image quality and radiation dose of prospectively ECG-triggered high-pitch coronary CT angiography (CCTA) with 30 mL contrast agent at 70 kVp.

Methods

Fifty-eight patients with suspected coronary artery disease, a body mass index (BMI) of less than 25 kg/m², sinus rhythm and a heart rate (HR) of less than 70 beats per minute (bpm) were prospectively enrolled in this study. Thirty mL of 370 mg I/mL iodinated contrast agent was administrated at a flow rate of 5 mL/s. All patients underwent prospectively ECG-triggered high-pitch CCTA on a second-generation dual-source CT system at 70 kVp using automated tube current modulation.

Results

Fifty-six patients (96.6 %) had diagnostic CCTA images and two patients (3.4 %) had one vessel with poor image quality each rated as non-diagnostic. No significant effects of HR, HR variability and BMI on CCTA image quality were observed (all P?>?0.05). Effective dose was 0.17?±?0.02 mSv and the size-specific dose estimate was 1.03?±?0.13 mGy.

Conclusion

Prospectively ECG-triggered high-pitch CCTA at 70 kVp with 30 mL of contrast agent can provide diagnostic image quality at a radiation dose of less than 0.2 mSv in patients with a BMI of less than 25 kg/m² and an HR of less than 70 bpm.

Key points

? Prospectively ECG-triggered high-pitch CCTA at 70 kVp/30 mL contrast agent is feasible. ? Diagnostic image quality can be obtained at a radiation dose of less than 0.2 mSv. ? This protocol is suitable for normal-weight patients with slow heart rate.     

Detection of coronary artery stenosis with sub-milliSievert radiation dose by prospectively ECG-triggered high-pitch spiral CT angiography and iterative reconstruction

Objectives

To evaluate the diagnostic accuracy of sub-milliSievert (mSv) coronary CT angiography (cCTA) using prospectively ECG-triggered high-pitch spiral CT acquisition combined with iterative image reconstruction.

Methods

Forty consecutive patients (52.9?±?8.7 years; 30 men) underwent dual-source cCTA using prospectively ECG-triggered high-pitch spiral acquisition. The tube current-time product was set to 50 % of standard-of-care CT examinations. Images were reconstructed with sinogram-affirmed iterative reconstruction. Image quality was scored and diagnostic performance for detection of ≥50 % stenosis was determined with catheter coronary angiography (CCA) as the reference standard.

Results

CT was successfully performed in all 40 patients. Of the 601 assessable coronary segments, 543 (90.3 %) had diagnostic image quality. Per-patient sensitivity for detection of ≥50 % stenosis was 95.7 % [95 % confidence interval (CI), 76.0-99.8 %] and specificity was 94.1 % (95 % CI, 69.2-99.7 %). Per-vessel sensitivity was 89.5 % (95 % CI, 77.8-95.6 %) with 93.2 % specificity (95 % CI, 86.0-97.0 %). The area under the receiver-operating characteristic curve on per-patient and per-vessel levels was 0.949 and 0.913. Mean effective dose was 0.58?±?0.17 mSv. Mean size-specific dose estimate was 3.14?±?1.15 mGy.

Conclusions

High-pitch prospectively ECG-triggered cCTA combined with iterative image reconstruction provides high diagnostic accuracy with a radiation dose below 1 mSv for detection of coronary artery stenosis.

Key Points

? Cardiac CT with sub-milliSievert radiation dose is feasible in many patients ? High-pitch spiral CT acquisition with iterative reconstruction detects coronary stenosis accurately. ? Iterative reconstruction increases who can benefit from low-radiation cardiac CT.     

Diagnostic accuracy of low-dose 256-slice multi-detector coronary CT angiography using iterative reconstruction in patients with suspected coronary artery disease

Objectives

To evaluate the accuracy of low-dose coronary CTA with iterative reconstruction (IR) in the diagnosis of coronary artery disease (CAD) in patients with suspected CAD.

Methods

Ninety-six patients with suspected CAD underwent low-dose prospective electrocardiogram-gated coronary CTA, with images reconstructed using IR. Image quality (IQ) of coronary segments were graded on a 4-point scale (4, excellent; 1, non-diagnostic). With invasive coronary angiography (ICA) considered the “gold standard”, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of coronary CTA were calculated on segment-, vessel- and patient-based levels. The patient data were divided into two groups (Agatston scores of ≥ 400 and <400). The differences in diagnostic performance between the two groups were tested.

Results

Diagnostic image quality was found in 98.1 % (1,232/1,256) of segments. The sensitivity, specificity, PPV, NPV and accuracy were 90.8 %, 95.3 %, 81.8 %, 97.8 % and 94.3 % (segment-based) and 97.2 %, 83.3 %, 94.6 %, 90.9 % and 93.8 % (patient-based). Significant differences between the two groups were seen in specificity, PPV and accuracy (92.1 % vs. 97.9 %, 76.0 % vs. 86.7 %, 91.7 % vs. 96.6 %, P?<?0.05; segment-based). The average effective dose was 1.30?±?0.15 mSv.

Conclusion

Low-dose prospective coronary CTA with IR can acquire satisfactory image quality and show high diagnostic accuracy in patients with suspected CAD; however, blooming continues to pose a challenge in severely calcified segments.

Key Points

? Coronary artery disease (CAD) is increasingly investigated using coronary CTA. ? The iterative reconstruction (IR) algorithm is promising in decreasing radiation doses. ? Low-dose prospective coronary CTA with IR can acquire satisfactory image quality. ? Low-dose prospective coronary CTA with IR can show high diagnostic accuracy.     

Diffusion-weighted MR imaging for the diagnosis of abscess complicating fistula-in-ano: preliminary experience

Objective

To investigate the role of diffusion-weighted magnetic resonance imaging (DWMRI) in the diagnosis of abscess-complicating fistula-in-ano.

Methods

This retrospective study was approved by our Institutional Review Board and informed consent was waived. MRI examinations, including fat-suppressed T2-weighted turbo spin-echo (T2-TSE) MRI and DWMRI, of 24 patients with a fistula-in-ano, were reviewed by two independent readers for the presence and number of visible fistulas, conspicuity and apparent diffusion coefficient (ADC) measurement of suspected fistula tracks and pelvic collections. The reference standard was surgical with follow-up findings.

Results

Sensitivity was 91.2 % [95 % CI: 76 %-98 %] for T2-weighted TSE MRI and 100 % [95 % CI: 90 %-100 %] for DWMRI detecting fistulas. ADC values were lower in abscesses than in inflammatory masses (P?=?0.714.10^-6). The area under the ROC curve was 0.971 and the optimal cut-off ADC value was 1.186?×?10^-3 mm²/s, yielding a sensitivity of 100 % [95 % CI: 77 %-100 %], a specificity of 90 % [95 % CI: 66 %-100 %], a positive predictive value of 93 % [95 % CI: 82.8 %-100 %] and a negative predictive value of 90 % [95 % CI: 78 %-100 %] for an abscess diagnosis. Fistula conspicuity was greater with DWMRI than with T2-TSE MRI for the two observers (P?=?0.0034 and P?=?0.0007).

Conclusion

DWMRI shows high sensitivity and specificity for the diagnosis of perianal abscesses and helps discriminate between an abscess and inflammatory mass. Conspicuity of fistulas-in-ano is greater with DWMRI than with T2-weighted TSE MRI.

Key Points

? DWMRI can differentiate between pelvic abscess and inflammatory mass. ? DWMRI helps avoid gadolinium-chelate administration in patients with a suspected fistula-in-ano. ? DWMRI provides high degrees of conspicuity for fistula-in-ano. ? Conspicuity of fistulas is better with DWMRI imaging than with T2-TSE-weighted MRI.     

Angiographic patterns of in-stent restenosis classified by computed tomography in patients with drug-eluting stents: correlation with invasive coronary angiography

Objectives

To evaluate the diagnostic accuracy of Mehran??s in-stent restenosis (ISR) classification by coronary computed angiography (CCTA), with reference to invasive coronary angiography (ICA).

Methods

Consecutive symptomatic patients, who had clinically suspected ISR and implanted stent diameter ?? 3?mm, were prospectively enrolled in our study. Mehran??s classification was employed by CCTA and ICA to classify ISR lesions into four subtypes: focal, diffuse intrastent, diffuse proliferative and total occlusion. CCTA and ICA measurement of lesion length was further compared.

Results

Sixty-one patients with 101 implanted stents were included in our study. The overall sensitivity, specificity, PPV and NPV of CCTA diagnosis of binary ISR, as shown by patient-based analysis (n?=?61), were 100?% (49/49), 75?% (8/12), 92.45?% (49/53) and 100?% (8/8) respectively. Mehran??s classification of CCTA correlated well with ICA findings. The diagnostic accuracy of CCTA for class I, class II, class III and class IV lesions was 92.5?%, 91.67?%, 100?% and 100?% respectively. Lesion length was assessed to be significantly longer with CCTA than with ICA (11.03?±?5.89?mm versus 8.56?±?4.99?mm, P?<?0.001).

Conclusions

Angiographic patterns of in-stent restenosis can be accurately classified by coronary computed angiography. The lesion length measured by CCTA is longer than that assessed by invasive coronary angiography

Key Points

? Patterns of in-stent restenosis can be accurately classified by coronary computed angiography. ? Lesion length appears longer on CCTA than on invasive coronary angiography. ? Stent occlusion is better delineated by coronary computed angiography. ? Optimal treatment can be planned pre-operatively based on CCTA evaluation.     

Malignancy rates and diagnostic performance of the Bosniak classification for the diagnosis of cystic renal lesions in computed tomography – a systematic review and meta-analysis

Objective

To systematically review the literature on the Bosniak classification system in CT to determine its diagnostic performance to diagnose malignant cystic lesions and the prevalence of malignancy in Bosniak categories.

Methods

A predefined database search was performed from 1 January 1986 to 18 January 2016. Two independent reviewers extracted data on malignancy rates in Bosniak categories and several covariates using predefined criteria. Study quality was assessed using QUADAS-2. Meta-analysis included data pooling, subgroup analyses, meta-regression and investigation of publication bias.

Results

A total of 35 studies, which included 2,578 lesions, were investigated. Data on observer experience, inter-observer variation and technical CT standards were insufficiently reported. The pooled rate of malignancy increased from Bosniak I (3.2 %, 95 % CI 0–6.8, I²?=?5 %) to Bosniak II (6 %, 95 % CI 2.7–9.3, I²?=?32 %), IIF (6.7 %, 95 % CI 5–8.4, I²?=?0 %), III (55.1 %, 95 % CI 45.7–64.5, I²?=?89 %) and IV (91 %, 95 % CI 87.7–94.2, I²?=?36). Several study design-related influences on malignancy rates and subsequent diagnostic performance indices were identified.

Conclusion

The Bosniak classification is an accurate tool with which to stratify the risk of malignancy in renal cystic lesions.

Key points

? The Bosniak classification can accurately rule out malignancy.? Specificity remains moderate at 74?% (95?% CI 64–82).? Follow-up examinations should be considered in Bosniak IIF and Bosniak II cysts.? Data on the influence of reader experience and inter-reader variability are insufficient.? Technical CT standards and publication year did not influence diagnostic performance.

     

Diagnostic performance of coronary CT angiography for stenosis detection according to calcium score: systematic review and meta-analysis

Objectives

A systematic review and meta-analysis to assess sensitivity and specificity of coronary CT angiography (CCTA) for significant stenosis at different degrees of coronary calcification.

Methods

A literature search was performed including studies describing test characteristics of CCTA for significant stenosis, performed with at least 16-MDCT and according to calcium score (CS). Invasive coronary angiography was the reference standard. Pooled sensitivity and specificity of CCTA by CS categories and CT equipment were calculated.

Results

Of 14,121 articles, 51 studies reported on the impact of calcium scoring on diagnostic performance of CCTA and could be included in the systematic review. Twenty-seven of these studies (5,203 participants) were suitable for meta-analysis. On a patient-basis, sensitivity of CCTA for significant stenosis was 95.8, 95.6, 97.6 and 99.0% for CS 0–100, 101–400, 401–1,000 and >1,000 respectively. Specificity was 91.2, 88.2, 50.6 and 84.0% respectively. Specificity of CCTA was significantly lower for CS 401–1,000 due to lack of patients without significant stenosis. Sensitivity and specificity of 16-MDCT were significantly lower compared to more modern CT systems.

Conclusions

Even in cases of severe coronary calcification, sensitivity and specificity of CCTA for significant stenosis are high. With 64-MDCT and newer CT systems, a CS cut-off for performing CCTA no longer seems indicated.

Key Points

? Decisions about performing coronary CT angiography (CCTA) sometimes depend on calcium scoring. ? CCTA is highly sensitive for coronary stenosis. ? With 16-MDCT, however, heavy calcification reduces specificity for significant stenosis. ? For 64-MDCT (and above), CCTA has high specificity, even with severe coronary calcification.     

Diagnostic accuracy of dual-source CT coronary angiography with prospective ECG-triggering on different heart rate patients

Objective

To evaluate the diagnostic accuracy of dual-source CT (DSCT) prospective ECG-triggering coronary angiography in patients with different heart rate (HR).

Methods

103 patients with suspected coronary artery disease underwent DSCT prospective ECG-triggered coronary angiography and invasive coronary angiography (ICA). The patients were grouped by HR during CT scans: low HR (??60?bpm, n?=?34); medium HR (60?n?=?36) and high HR (>70?bpm, n?=?33). The sensitivity and specificity of DSCT in detecting ??50% stenosis were compared among subgroups where ICA was the gold standard. Image quality was scored using a 4-point scale.

Results

A total of 1,580 (95.9%) coronary artery segments were evaluable. Sensitivity and specificity were 82.8% and 98.4%, 88.3% and 98.7%, and 80.3% and 98.6% for different subgroups (all p?>?0.05). The overall area under the curve of the receiver-operating characteristic analysis was 0.94. The image quality scores were 3.1?±?0.3, 3.1?±?0.3 and 3.0?±?0.4 for subgroups (p?>?0.05). The overall average effective radiation dose was 3.60?±?1.60?mSv.

Conclusion

DSCT coronary angiography with prospective ECG-triggering could be just as accurate in patients with medium to high HR compared to those with low HR.     

Impact of breast mass size on accuracy of ultrasound elastography vs. conventional B-mode ultrasound: a meta-analysis of individual participants

Objectives

To conduct an individual patient data meta-analysis comparing the diagnostic performance of ultrasound elastography (USE) versus B-mode ultrasound (USB) across size ranges of breast masses.

Methods

An extensive literature search of PubMed and other medical/general purpose databases from inception through August 2011 was conducted. Corresponding authors of published studies that reported a direct comparison of the diagnostic performance of USE using the elasticity score versus USB for characterisation of focal breast masses were contacted for their original patient-level data set. Summary diagnostic performance measures were compared for each test within and across three mass size groups (<10 mm, 10–19 mm, and >19 mm).

Results

The patient-level data sets were received from five studies, providing information on 1,412 breast masses. For breast masses <10 mm (n?=?543; 121 malignant), the sensitivity/specificity of USE and USB were 76 %/93 % and 95 %/68 %, respectively. For masses 10–19 mm of size (n?=?528; 247 malignant), sensitivity/specificity of USE and USB were 82 %/90 % and 95 %/67 %, respectively. For masses >19 mm of size (n?=?325; 162 malignant), sensitivity/specificity of USE and USB were 74 %/94 % and 97 %/55 %, respectively.

Conclusion

Regardless of the mass size, USE has higher specificity and lower sensitivity compared to USB in characterising breast masses. The performance of each of these two tests does not vary significantly by mass size.

Key Points

? Ultrasound elastography is increasingly used for breast lesions. ? Its diagnostic performance is not dependent on the size of the mass. ? Ultrasound elastography has higher specificity/lower sensitivity than B-mode ultrasound. ? Elastography is advised when B-mode results are equivocal.     

Diagnostic accuracy of high-resolution attenuation-corrected Anger-camera SPECT in the detection of coronary artery disease

Background

There is limited data on diagnostic accuracy of recently introduced high-resolution Anger (HRA) SPECT incorporating attenuation correction (AC), noise reduction, and resolution recovery algorithms. We therefore studied 54 consecutive patients (excluding those with prior MI or cardiomyopathy) who had HRA-AC SPECT and coronary angiography (CA) ≤ 30 days and no change in symptoms.

Methods

The HRA-AC studies were acquired in 128 × 128 matrix (3.2 mm pixel) format with simultaneous Gd-153 line-source AC. Measured variables were image quality, interpretive certainty, sensitivity and specificity for any CAD, sensitivity for single- and multivessel CAD, and the influence of gender, body mass index (BMI), and stress modality.

Results

The mean age of the patients was 66 ± 11 years with a BMI of 32 ± 7 kg·m^?2. Mean interpretive certainty score was 2.7 on a 3-point scale and mean image quality score was 3.3 on a 4-point scale. Stress perfusion defects were detected in 34 of 38 patients with obstructive CAD [sensitivity 89%, 95% confidence interval (CI) 76%-95%]. The specificity was 75% (CI 51%-90%) and overall diagnostic accuracy was 85% (CI 73%-92%). Accuracy did not differ for females vs males, for BMI ≤30 vs >30, or for pharmacologic vs exercise SPECT. Sensitivity for single-vessel disease was 88% (CI 69%-96%) and for multivessel disease was 93% (CI 69%-99%).

Conclusion

New Anger technology incorporating innovative improvements results in high image quality with excellent interpretive certainty and high diagnostic accuracy.     

Quantification and characterisation of coronary artery plaque volume and adverse plaque features by coronary computed tomographic angiography: a direct comparison to intravascular ultrasound

Objective

We evaluated the performance of manual measures of coronary plaque volumes and atherosclerotic plaque features from coronary CT angiography (CTA), using intravascular ultrasound (IVUS) as the reference.

Methods

Thirty individual coronary plaques with suitable fiduciary markers were identified. Plaque volumes on coronary CTA were manually quantified by two observers and compared to IVUS plaque volumes as interpreted by an independent laboratory. The presence of adverse plaque characteristics—low attenuation plaque (LAP), positive remodelling (PR) and spotty calcification (SC)—on coronary CTA was evaluated and compared to IVUS.

Results

High correlation in plaque volumes was detected between observers (r?=?0.94, P?<?0.0001; 95 % limits of agreement <48.7 mm³, bias 6.6 mm³). Excellent correlation (r?=?0.95, P?<?0.0001) was noted in plaque volume between independent observers and IVUS (95 % limits of agreement <40.6 mm³, bias ?4.4 mm³) and did not differ from IVUS (105.0?±?56.7 vs. 109.4?±?60.7 mm³, P?=?0.2). The frequency of LAP (10 % vs. 17 %), PR (7 % vs. 10 %) and SC (27 % vs. 33 %) was similar between coronary CTA and IVUS (all P?=?NS).

Conclusions

Plaque volume on coronary CTA determined by manual methods demonstrates high correlation and modest agreement to IVUS. Further, coronary CTA demonstrates high accuracy for the identification of adverse plaque characteristics, including LAP, PR and SC.

Key Points

? Coronary CT angiography is a non-invasive test that enables coronary plaque assessment ? Plaque quantification by coronary CT angiography correlates well with intravascular ultrasound findings ? Coronary CT angiography can identify adverse plaque characteristics     

Effect of vascular haemoglobin concentrations on ultrasound-guided diffuse optical tomography in differentiating benign from malignant breast lesions

Objectives

Ultrasound-guided diffuse optical tomography (US-DOT) can potentially detect breast carcinomas by measuring total tumour haemoglobin concentrations (TTHC). The purpose of this study was to evaluate whether vascular haemoglobin concentrations (VHC) affect the ability of US-DOT to distinguish breast carcinomas from benign.

Materials and methods

In 85 women (97 palpable lesions) referred for core breast biopsy, we measured VHC with a complete blood count and calculated TTHCs for each lesion with US-DOT. Anaemia was defined as a VHC less than 120.0 g/L.

Results

Mean TTHCs were significantly higher in malignant lesions (n?=?53) than in benign lesions (n?=?44), regardless of whether the lesions were from women with anaemia (TTHC, 248.5 vs. 123.3 μmol/L; P?=?0.001) or from those without (TTHC, 229.7 vs. 173.9 μmol/L; P?=?0.016). A cut-off TTHC of 155.1 μmol/L provided 81.3 % sensitivity, 81.8 % specificity and 81.5 % accuracy for detecting malignant tumours in women with anaemia and 78.4 % sensitivity, 54.5 % specificity and 67.1 % accuracy for women without. There was no significant difference in sensitivity (P?=?0.813), specificity (P?=?0.108) and accuracy (P?=?0.162) between the anaemic group and the non-anaemic group.

Conclusions

Vascular haemoglobin concentrations did not affect the ability of US-DOT to differentiate breast carcinomas from benign lesions.

Key Points

? US-DOT can differentiate benign from malignant breast lesions by measuring TTHC. ? No difference in TTHC between the anaemia and non-anaemia group. ? Vascular haemoglobin concentrations do not affect the diagnostic ability of US-DOT.     

PET/CT assessment in follicular lymphoma using standardized criteria: central review in the PRIMA study

Purpose

We aimed to compare the standardized central review of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT scans performed after induction therapy for follicular lymphoma (FL) in the PRIMA study (Salles et al., Lancet 377:42–51, 2011; Trotman et al., J Clin Oncol 29:3194–3200, 2011) to scan review at local centres.

Methods

PET/CT scans were independently evaluated by two nuclear medicine physicians using the 2007 International Harmonization Project (IHP) criteria (Cheson et al., J Clin Oncol 25:579–586, 2007; Juweid et al., J Clin Oncol 25:571–578, 2007; Shankar et al., J Nucl Med 47:1059–1066, 2006) and Deauville 5-point scale (5PS) criteria (Meignan et al., Leuk Lymphoma 50:1257–1260, 2009; Meignan et al., Leuk Lymphoma 51:2171–2180, 2010; Barrington et al., Eur J Nucl Med Mol Imaging 37:1824–1833, 2010). PET/CT status was compared with prospectively recorded patient outcomes.

Results

Central evaluation was performed on 119 scans. At diagnosis, 58 of 59 were recorded as positive, with a mean maximum standardized uptake value (SUV_max) of 11.7 (range 4.6–35.6). There was no significant association between baseline SUV_max and progression-free survival (PFS). Sixty post-induction scans were interpreted using both the IHP criteria and 5PS. Post-induction PET-positive status failed to predict progression when applying the IHP criteria [p?=?0.14; hazard ratio (HR) 1.9; 95 % confidence interval (CI) 0.8–4.6] or 5PS with a cut-off ≥3 (p?=?0.12; HR 2.0; 95 % CI 0.8–4.7). However, when applying the 5PS with a cut-off ≥4, there was a significantly inferior 42-month PFS in PET-positive patients of 25.0 % (95 % CI 3.7–55.8 %) versus 61.4 % (95 % CI 45.4–74.1 %) in PET-negative patients (p?=?0.01; HR 3.1; 95 % CI 1.2–7.8). The positive predictive value (PPV) of post-induction PET with this liver cut-off was 75 %. The 42-month PFS for patients remaining PET-positive by local assessment was 31.1 % (95 % CI 10.2–55.0 %) vs 64.6 % (95 % CI 47.0–77.6 %) for PET-negative patients (p?=?0.002; HR 3.3; 95 % CI 1.5–7.4), with a PPV of 66.7 %.

Conclusion

We confirm that FDG PET/CT status when applying the 5PS with a cut-off ≥4 is strongly predictive of outcome after first-line immunochemotherapy for FL. Further efforts to refine the criteria for assessing minimal residual FDG uptake in FL should provide a reproducible platform for response assessment in future prospective studies of a PET-adapted approach.