Craniofacial gunshot injuries: an unrecognised risk factor for blunt cervical vascular injuries?

Objectives

To review our institutional experience with cervical arterial injuries remote from the penetrating tract seen in the setting of craniofacial gunshot injuries.

Methods

Institutional Review Board approval was obtained. Our institutional trauma registry was queried over a 5-year period for patients with cervical arterial injuries due to penetrating craniofacial gunshot wounds who underwent CT angiography. Imaging results and clinical notes were reviewed.

Results

A total of 427 patients sustained gunshot wounds to the head, face and/or neck, of whom 222 underwent CT angiography yielding 56 patients with 78 vascular injuries. There were five internal carotid artery injuries remote from the wound tract. The incidence of these “indirect” cervical arterial injuries in our patient population was 1.2%, or 2.8% of patients who underwent CT angiography.

Conclusions

The incidence of “indirect” cervical arterial injuries with craniofacial gunshot wounds is comparable to or slightly higher than those seen in pure blunt trauma. Screening patients with craniofacial gunshot injuries with CT angiography may yield unexpected cervical vascular injuries remote from the penetrating tract. The significance and optimal therapy of these injuries are unknown. Additional experience will be needed to determine the significance of “indirect” cervical arterial injuries in the setting of craniofacial gunshot wounds.

Key Points

? There are several known risk factors for blunt cervical arterial injuries. ? Cervical arterial injuries may occur remote from the wound following craniofacial gunshot wounds. ? Craniofacial gunshot wounds pose a risk for blunt cervical vascular injuries.     

CT-detected traumatic small artery extremity injuries: surgery,embolize, or watch? A 10-year experience

Advances in computed tomography (CT) angiography have increased the sensitivity and specificity of detecting small branch arterial injuries in the extremities of trauma patients. However, it is unclear whether these patients should undergo surgery, angioembolization, or conservative watchful waiting. We hypothesized that uncomplicated small arterial branch injuries can be managed successfully with watchful waiting. A 10-year retrospective review of extremity CT angiograms with search findings of arterial “active extravasation” or “pseudoaneurysm” was performed at a level 1 county trauma center. Subgroup analysis was performed on those with isolated extremity injury and those with concurrent injuries. A total of 31 patients had CT-detected active extravasation (84 %) or pseudoaneurysm (16 %), 71 % of which were isolated vascular injuries. Of the patients evaluated, 71 % (n?=?22) were managed with watchful waiting, 19 % (n?=?6) with angioembolization, and 10 % (n?=?3) with surgery. Watchful waiting complications included progression to alternative treatment (n?=?1) and blood transfusions (n?=?2). Complications of surgery included the inability to find active bleeding (n?=?1) and postoperative psychosis (n?=?1). Complications of angioembolization were limited to a postprocedure blood transfusion (n?=?1). Patients with isolated vascular injuries had an average length of stay of 2.9 days, with management averages of the following: 2.7 days with watchful waiting (n?=?16), 3.3 days with angioembolization (n?=?3), and 3.7 days with surgery (n?=?3). CT angiography has greatly increased the reported incidence of traumatic arterial injury in the extremity. We propose that small branch arterial injuries in the extremities can be managed successfully with watchful waiting and do not often require immediate embolization.     

Subtracted 3D CT angiography for the evaluation of intracranial aneurysms in 256-slice multidetector CT: usefulness of the 80-kVp plus compact contrast medium bolus protocol

Objectives

To evaluate the usefulness of an 80-kVp and compact contrast material protocol for arterial phase subtracted cerebral 3D-CTA using 256-slice multidetector CT.

Methods

Thirty-two patients underwent CT with 100 kVp and received a contrast dose of 370 mgI/kg body weight over 15 s (protocol A). Thirty-three patients underwent CT with 100 kVp and received a contrast dose of 296 mgI/kg body weight over 10 s (protocol B). Thirty-three other patients underwent CT with 80 kVp and received a contrast medium dose of 296 mgI/kg body weight over 10 s (protocol C). We compared the arterial attenuation and contrast noise ratio (CNR) of each protocol. Two independent readers assessed overall image quality.

Results

Arterial attenuation was significantly higher under protocols A (418.6?±?71.1 HU) and C (442.7?±?79.3 HU) than under protocol B (355.8?±?107.2 HU; P?<?0.05). The CNR of protocol C (26.1?±?6.1) was higher than that of protocol A (20.7?±?8.4; P?<?0.05). The overall image quality of protocol A was higher than that of protocol C (P?<?0.01).

Conclusion

The 80-kVp plus compact contrast protocol is well suited to arterial phase subtracted cerebral 3D-CTA without confounding venous enhancement.

Key Points

? Subtracted 3D CT angiography is useful in the evaluation of intracranial aneurysms. ? A compact contrast material protocol increased arterial attenuation without venous contamination. ? Low-kVp CT compensated for the decreased amount of contrast medium. ? An 80-kVp CT with a compact enhancement bolus provides good intracranial 3D-CT angiography.     

Diagnostic accuracy of 128-slice dual-source CT coronary angiography: a randomized comparison of different acquisition protocols

Objectives

To compare the diagnostic performance and radiation exposure of 128-slice dual-source CT coronary angiography (CTCA) protocols to detect coronary stenosis with more than 50 % lumen obstruction.

Methods

We prospectively included 459 symptomatic patients referred for CTCA. Patients were randomized between high-pitch spiral vs. narrow-window sequential CTCA protocols (heart rate below 65 bpm, group A), or between wide-window sequential vs. retrospective spiral protocols (heart rate above 65 bpm, group B). Diagnostic performance of CTCA was compared with quantitative coronary angiography in 267 patients.

Results

In group A (231 patients, 146 men, mean heart rate 58?±?7 bpm), high-pitch spiral CTCA yielded a lower per-segment sensitivity compared to sequential CTCA (89 % vs. 97 %, P?=?0.01). Specificity, PPV and NPV were comparable (95 %, 62 %, 99 % vs. 96 %, 73 %, 100 %, P?>?0.05) but radiation dose was lower (1.16?±?0.60 vs. 3.82?±?1.65 mSv, P?<?0.001). In group B (228 patients, 132 men, mean heart rate 75?±?11 bpm), per-segment sensitivity, specificity, PPV and NPV were comparable (94 %, 95 %, 67 %, 99 % vs. 92 %, 95 %, 66 %, 99 %, P?>?0.05). Radiation dose of sequential CTCA was lower compared to retrospective CTCA (6.12?±?2.58 vs. 8.13?±?4.52 mSv, P?<?0.001). Diagnostic performance was comparable in both groups.

Conclusion

Sequential CTCA should be used in patients with regular heart rates using 128-slice dual-source CT, providing optimal diagnostic accuracy with as low as reasonably achievable (ALARA) radiation dose.

Key Points

? 128-slice dual-source CT coronary angiography offers several different acquisition protocols. ? Randomized comparison of protocols reveals an optimal protocol selection strategy. ? Appropriate CTCA protocol selection lowers radiation dose, while maintaining high quality. ? CTCA protocol selection should be based on individual patient characteristics. ? A prospective sequential protocol is preferred for CTCA.     

A new low-dose multi-phase trauma CT protocol and its impact on diagnostic assessment and radiation dose in multi-trauma patients

Purpose

Computed tomography (CT) examinations, often using high-radiation dosages, are increasingly used in the acute management of polytrauma patients. This study compares a low-dose polytrauma multi-phase whole-body CT (WBCT) protocol on a latest generation of 16-cm detector 258-slice multi-detector CT (MDCT) scanner with advanced dose reduction techniques to a single-phase polytrauma WBCT protocol on a 64-slice MDCT scanner.

Methods

Between March and September 2015, 109 polytrauma patients (group A) underwent acute WBCT with a low-dose multi-phase WBCT protocol on a 258-slice MDCT whereas 110 polytrauma patients (group B) underwent single-phase trauma CT on a 64-slice MDCT. The diagnostic accuracy to trauma-related injuries, radiation dose, quantitative and semiquantitative image quality parameters, subjective image quality scorings, and workflow time parameters were compared.

Results

In group A, statistically significantly more arterial injuries (p = 0.04) and arterial dissections (p = 0.002) were detected. In group A, the mean (±SD) dose length product value was 1681 ± 183 mGy*cm and markedly lower when compared to group B (p < 0.001). The SDs of the mean Houndsfield unit values of the brain, liver, and abdominal aorta were lower in group A (p < 0.001). Mean signal-to-noise ratios (SNRs) for the brain, liver, and abdominal aorta were significantly higher in group A (p < 0.001). Group A had significantly higher image quality scores for all analyzed anatomical locations (p < 0.02). However, the mean time from patient registration until completion of examination was significantly longer for group A (p < 0.001).

Conclusions

The low-dose multi-phase CT protocol improves diagnostic accuracy and image quality at markedly reduced radiation. However, due to technical complexities and surplus electronic data provided by the newer low-dose technique, examination time increases, which reduces workflow in acute emergency situations.

     

Evaluation of the diagnostic value of a venous phase in CT angiography of the extremities in the setting of trauma: is vein imaging in vain?

Purpose

This study examined the value of including a venous phase in addition to the initial arterial phase in the CT angiography evaluation of extremity trauma.

Methods

CT studies from 157 patients (average age 38 years, age range 18–89 years, male 83%, female 17%) were obtained for trauma to the upper or lower extremity with both arterial and venous phases and retrospectively reviewed. The detection rate and type of vascular injury were evaluated by using the arterial phase alone and compared to the detection rate when interpreting the arterial and venous phases together.

Results

Arterial injury was identified in 35 cases (22%), and venous injury was identified in seven cases (5%). Four cases of discrepant diagnoses were identified between image interpretation of the arterial phase alone and interpretation using both phases, all of which were venous injuries that were visible only on the venous phase. None of the four cases of venous injury required a change in surgical management. Overall, no significant difference in diagnosis between the two methods of image interpretation (arterial phase alone, arterial and venous phases) was discovered (p > 0.125; CI 95%).

Conclusions

The use of a venous phase in the CT angiography evaluation of extremity trauma does not add significant arterial diagnostic or clinical management value despite its potential of increasing the diagnostic detection rate of venous injury.

     

Transcatheter embolisation of iatrogenic renal vascular injuries

Purpose

The aim of our study was to review our experience and long-term follow-up in the treatment of iatrogenic renal vascular injuries using transcatheter embolisation.

Materials and methods

Our retrospective analysis of cases collected in two interventional centres consists of a total of 21 patients who underwent renal arterial embolisation (RAE) for iatrogenic arterial kidney bleeding. Biopsy (n = 4), percutaneous nephrolithotomy (n = 4), nephron-sparing surgery (n = 4), guidewire-induced arterial perforation during coronary angiography or renal stenting (n = 3), percutaneous nephrostomy (n = 3), renal endopyelotomy/pyeloplasty (n = 2) and surgical nephrectomy were the iatrogenic causes. Seven patients presented with haemodynamic instability requiring blood transfusion (33.3 %), the remaining were haemodynamically stable (66.7 %). Diagnostic renal angiography revealed 9 actively bleeding vessels, 6 pseudoaneurysms, 4 arteriovenous fistulas and 1 arterio-calyceal fistula. In one patient selective renal arteriography was negative probably because the bleeding observed at CT angiography was self-limited. Twenty-one embolisation procedures were performed in 20 patients; one patient required a second embolisation 3 h after the first one. Embolisation was performed with microcoils, polyvinyl alcohol particles, embospheres, spongostan emulsion and vascular plug.

Results

The technical success rate was 100 %. The overall clinical success rate was 95 %. Apart from a patient who died due to disseminated intravascular coagulation, no major complications requiring intensive care treatment were encountered during or after the procedures. No patient required emergency surgery or subsequent surgical treatment. No statistically significant differences in eGFR or renal function stage appeared after RAE.

Conclusions

Percutaneous treatment can be proposed as a first-line treatment in iatrogenic renal arterial injuries, resulting in a safe and effective procedure.     

Accuracy of CT angiography in the diagnosis of acute gastrointestinal bleeding: systematic review and meta-analysis

Objective

To assess the diagnostic accuracy of computed tomography (CT) angiography in the evaluation of patients with an episode of acute gastrointestinal haemorrhage.

Methods

Systematic review and meta-analysis to estimate pooled accuracy indices. A bivariate random effects model was adjusted to obtain a summary receiver-operating characteristic (sROC) curve and the corresponding area under the curve (AUC).

Results

Twenty-two studies were included and provided data on 672 patients (range of age 5–74) with a mean age of 65 years. The overall sensitivity of CT angiography for detecting active acute GI haemorrhage was 85.2 % (95 % CI 75.5 % to 91.5 %). The overall specificity of CT angiography was 92.1 % (95 % CI 76.7 % to 97.7 %). The likelihood ratios for positive and negative test results were 10.8 (95 % CI 3.4 to 34.4) and 0.16 (95 % CI 0.1 to 0.27) respectively, with an AUC of 0.935 (95 % CI 0.693 to 0.989). The sources of heterogeneity explored had no significant impact on diagnostic performance.

Conclusions

CT shows high diagnostic accuracy and is an excellent diagnostic tool for detection and localising of intestinal bleeding sites. It is highly available, provides fast detection and localisation of the bleeding site, and is minimally invasive.

Key Points

? CT angiography is increasingly used for investigating severe gastrointestinal bleeding. ? This systematic review and meta-analysis updates previous ones. ? In patients with massive gastrointestinal bleeding, CT angiography/MDCT detects bleeding accurately. ? CT angiography is useful in locating the bleeding site and determining appropriate treatment.     

Intra-arterial Ultra-low-Dose CT Angiography of Lower Extremity in Diabetic Patients

Purpose

To image lower extremity arteries by CT angiography using a very low-dose intra-arterial contrast medium in patients with high risk of developing contrast-induced nephropathy (CIN).

Materials and Methods

Three cases with long-standing diabetes mellitus and signs of lower extremity atherosclerotic disease were evaluated by CT angiography using 0.1 ml/kg of the body weight of contrast medium given via 10-cm-long 4F introducer by puncturing the CFA. Images were evaluated by an interventional radiologist and a cardiovascular surgeon. Density values of the lower extremity arteries were also calculated. Findings in two cases were compared with digital subtraction angiography images performed for percutaneous revascularization. Blood creatinine levels were followed for possible CIN.

Results

Intra-arterial CT angiography images were considered diagnostic in all patients and optimal in one patient. No patient developed CIN after intra-arterial CT angiography, while one patient developed CIN after percutaneous intervention.

Conclusion

Intra-arterial CT angiography of lower extremity might be performed in selected patients with high risk of developing CIN. Our limited experience suggests that as low as of 0.1 ml/kg of the body weight of contrast medium may result in adequate diagnostic imaging.

     

Topogram-based automated selection of the tube potential and current in thoraco-abdominal trauma CT – a comparison to fixed kV with mAs modulation alone

Objective

To investigate the impact of automated attenuation-based tube potential selection on image quality and exposure parameters in polytrauma patients undergoing contrast-enhanced thoraco-abdominal CT.

Methods

One hundred patients were examined on a 16-slice device at 120 kV with 190 ref.mAs and automated mA modulation only. Another 100 patients underwent 128-slice CT with automated mA modulation and topogram-based automated tube potential selection (autokV) at 100, 120 or 140 kV. Volume CT dose index (CTDI_vol), dose–length product (DLP), body diameters, noise, signal-to-noise ratio (SNR) and subjective image quality were compared.

Results

In the autokV group, 100 kV was automatically selected in 82 patients, 120 kV in 12 patients and 140 kV in 6 patients. Patient diameters increased with higher kV settings. The median CTDI_vol (8.3 vs. 12.4 mGy; ?33 %) and DLP (594 vs. 909 mGy cm; ?35 %) in the entire autokV group were significantly lower than in the group with fixed 120 kV (p?<?0.05 for both). Image quality remained at a constantly high level at any selected kV level.

Conclusion

Topogram-based automated selection of the tube potential allows for significant dose savings in thoraco-abdominal trauma CT while image quality remains at a constantly high level.

Key Points

? Automated kV selection in thoraco-abdominal trauma CT results in significant dose savings ? Most patients benefit from a 100-kV protocol with relevant DLP reduction ? Constantly good image quality is ensured ? Image quality benefits from higher kV when arms are positioned downward     

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.     

Triphasic CT in the diagnosis of acute mesenteric ischaemia

Objective

To evaluate the yield of each phase in a triphasic CT protocol used to diagnose acute mesenteric ischaemia (AMI).

Methods

Retrospective analysis of patients who underwent CT to exclude AMI was conducted. From 218 patients, 80 were randomly selected for analysis: 39 with proven AMI; 41 controls. Three readers evaluated the studies; two readers were provided with only portions of the examination to determine the yield of unenhanced CT (NECT) and CT angiography (CTA). The diagnostic accuracy of CT findings was calculated and compared between readers.

Results

The sensitivity and specificity of submucosal haemorrhage were 10 % and 98 %. Interobserver variability was poor (κ?=?0.17). All true-positive cases had other CT findings of AMI (n?=?4). There was no difference in the assessment of bowel enhancement between readers (P?<?0.05). There was no difference between readers (P?<?0.05) and interobserver variability was moderate to good when diagnosing arterial abnormalities without CTA. Sample size was small and errors occurred when using only the portal venous phase for this purpose.

Conclusion

NECT is not required for diagnosis of AMI. Splanchnic arterial abnormalities can be diagnosed without CTA although errors occur when using only the portal venous phase for this purpose.

Key points

? Triphasic CT is the current gold standard for diagnosing acute mesenteric ischaemia. ? Multiphase CT multiplies the radiation dose when compared to single phase CT. ? Each phase in a multiphase CT examination should be independently validated. ? Unenhanced CT is not required for diagnosis of acute mesenteric ischaemia. ? CT angiography should be performed for diagnosis of acute mesenteric ischaemia.     

Quantitative assessment of right ventricular function and pulmonary regurgitation in surgically repaired tetralogy of Fallot using 256-slice CT: comparison with 3-Tesla MRI

Objectives

To compare 256-slice cardiac computed tomography (CCT) with cardiac magnetic resonance (CMR) imaging to assess right ventricular (RV) function and pulmonary regurgitant fraction (PRF) in patients with repaired tetralogy of Fallot (TOF).

Methods

Thirty-three consecutive patients with repaired TOF underwent retrospective ECG-gated CCT and 3-Tesla CMR. RV and left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and ejection fraction (EF) were measured using CCT and CMR. PRF-CCT (%) was defined as (RVSV???LVSV)/RVSV. PRF-CMR (%) was measured by the phase-contrast method. Repeated measurements were performed to determine intra- and interobserver variability.

Results

CCT measurements, including PRF, correlated highly with the CMR reference (r?=?0.71–0.96). CCT overestimated RVEDV (mean difference, 17.1?±?2.9 ml), RVESV (12.9?±?2.1 ml) and RVSV (4.2?±?2.0 ml), and underestimated RVEF (?2.6?±?1.0 %) and PRF (?9.1?±?2.0 %) compared with CMR. The limits of agreement between CCT and CMR were in a good range for all measurements. The variability in CCT measurements was lower than those in CMR. The estimated effective radiation dose was 7.6?±?2.6 mSv.

Conclusions

256-slice CCT can assess RV function and PRF with relatively low dose radiation exposure in patients with repaired TOF, but overestimates RV volume and underestimates PRF.

Key points

? 256-slice CT assessment of RV function is highly reproducible in repaired TOF. ? Pulmonary regurgitation can be evaluated by biventricular systolic volume difference. ? CT overestimates RV volume and underestimates pulmonary regurgitation, compared with MRI.     

Image quality and radiation dose of low tube voltage 3rd generation dual-source coronary CT angiography in obese patients: a phantom study

Objectives

To assess the influence of tube potential on radiation dose and image quality of third-generation dual-source coronary CT angiography (CTA) in a phantom simulating an obese patient.

Methods

A thoracic phantom was equipped with tubular inserts containing iodine solution and water. A soft-tissue-equivalent ring around the phantom simulated an obese patient. Images were acquired at tube potentials of 80, 100, 120 and 140 kV with second-generation dual-source CT (DSCT) and 70–150 kV (in 10-kV increments) with third-generation DSCT. Contrast-to-noise ratio (CNR) was calculated and CT dose index was recorded.

Results

With second-generation DSCT, CNR was highest for 120 kV (19.0) and decreased with lower tube potential (12.0 at 80 kV) owing to disproportionately increased image noise. With third-generation DSCT, 70- and 80-kV acquisitions showed a smaller increase in noise. CNRs for third-generation DSCT were highest for 70 and 80 kV (21.1 and 21.2, respectively). Compared to 120 kV, radiation dose was 68 % and 49 % lower at 70 kV and 80 kV, respectively.

Conclusion

Third-generation DSCT enables one to perform coronary CTA at 70–80 kV in obese patients without compromising CNR and thus reduces radiation dose by 49–68 %.

Key points

? Low tube potential CT angiography is currently not suitable for obese patients. ? Third-generation DSCT offers substantially increased tube power at low tube potential. ? This enables one to perform coronary CT angiography at 70–80 kV in obese patients. ? Signal-to-noise ratio is maintained owing to increased tube current. ? This approach can be expected to reduce radiation dose by 49–68 %.     

Assessment of dose exposure and image quality in coronary angiography performed by 640-slice CT: a comparison between adaptive iterative and filtered back-projection algorithm by propensity analysis

Purpose

This study was performed to confirm, by propensity score matching, whether the use of adaptive–iterative dose reduction (AIDR 3D) with a built-in automatic exposure control system provides clinical and dosimetric advantages with respect to the traditional filtered back-projection (FBP) algorithm without automatic exposure modulation.

Materials and methods

A total of 200 consecutive patients undergoing coronary computed tomography (CT) angiography on a 640-slice CT scanner were studied. A protocol with exposure parameters based on patient body mass index (BMI) and with images reconstructed using FBP (group A) was compared with a protocol with images acquired using tube current decided by an automatic exposure control system and reconstructed using AIDR (group B). Mean effective dose and image quality with both objective and subjective measurements were assessed.

Results

Mean effective dose was 23.6 % lower in group B than in group A (2.56 versus 3.34 mSv; p < 0.0001). Noise was significantly lower in group B with consequent higher signal-to-noise (SNR) and contrast-to-noise (CNR) (p < 0.0001) compared with group A. Subjective quality parameters were also significantly higher in group B.

Conclusions

Comparative analysis by propensity score matching confirms that AIDR 3D with automatic exposure control is able to reduce significantly the mean radiation dose and improve the image quality compared with traditional FBP without exposure modulation.     

Can sufficient preoperative information of intracranial aneurysms be obtained by using 320-row detector CT angiography alone?

Purpose

To determine whether sufficient pre-surgical treatment information of unruptured intracranial aneurysms can be obtained by using 320-row detector CT angiography (CTA) alone.

Materials and methods

We enrolled 40 consecutive patients with unruptured intracranial aneurysms. All patients were prospectively conducted to perform 320-detector CTA as the only preoperative modality. Two blinded readers independently assessed CTA images. Interobserver agreement and the agreement between CTA and surgical findings were determined by calculating the κ coefficient. The referring neurosurgeons judged the usefulness of the information provided by CTA for treatment decisions.

Results

All patients had surgery without intraarterial digital subtraction angiography. Agreement between CTA and surgical findings was excellent for the aneurysm location (κ = 1.0) and good for the shape (κ = 0.71), neck (κ = 0.74) and its relationship with adjacent branches (κ = 0.71). Information obtained with 320-detector CTA was highly useful for surgical treatment in 37 of 40 (93 %) patients, although small perforators deriving from the aneurysm in 2 cases were not fully visualized on CTA images.

Conclusion

In most patients with unruptured intracranial aneurysms, sufficient pre-surgical treatment information can be obtained by using 320-detector CTA alone.     

Quantitative assessment of stenosis severity and atherosclerotic plaque composition using 256-slice computed tomography

Objective

To quantitatively estimate lumen narrowing and to assess the volume and composition of atherosclerotic plaque with 256-slice computed tomography angiography (CTA), using conventional quantitative coronary angiography (QCA) as the gold standard.

Methods

Twenty-seven consecutive patients with suspected coronary artery disease (CAD) underwent 256-slice CTA and subsequent coronary angiography within 4 weeks. Quantification of lumen narrowing was performed on curved multiplanar reformatted CTA images, in identical projections to those used for QCA. Atherosclerotic plaque volume and composition were assessed by using commercially available software.

Results

The overall correlation between the stenosis severity by QCA compared with CTA was high (r ²?=?0.79, p?<?0.001). For the detection of ≥50% and ≥75% diameter lesions, CTA yielded high sensitivity, specificity and accuracy (86%, 95% and 90%; and 89%, 100% and 96%, respectively), using QCA as the standard reference. Furthermore, assessment of atherosclerotic plaque yielded highly reproducible results (inter-observer and intra-variability of 13% and 9%, respectively, for the assessment of plaque volume, and high agreement between observers (κ?=?0.86) for the differentiation between non-calcified, mixed and calcified plaque).

Conclusions

Clinically indicated 256-slice CT angiography in symptomatic patients can aid both quantification of lumen narrowing and evaluation of atherosclerotic plaque, with high reproducibility.     

High-pitch dual-source CT angiography of supra-aortic arteries: assessment of image quality and radiation dose

Introduction

High-pitch CT angiography (CTA) is a recent innovation that allows significant shortening of scan time with volume coverage of 43 mm per second. The aim of our study was to assess this technique in CTA of the head and neck.

Methods

CTA of supra-aortic arteries was performed in 50 patients using two acquisition protocols: conventional single-source 64-slice (pitch 1.2) and high-pitch dual-source 128-slice CT (pitch 3.2). Subjective and objective image quality of supra-aortic vessel ostia as well as intra- and extra-cranial segments was retrospectively assessed by blinded readers and radiation dose compared between the two protocols.

Results

Conventional and high-pitch CTA achieved comparable signal-to-noise ratios in arterial (54.3?±?16.5 versus 57.3?±?14.8; p?=?0.50) and venous segments (15.8?±?6.7 versus 18.9?±?8.9; p?=?0.21). High-pitch scanning was, however, associated with sharper delineation of vessel contours and image quality significantly improved at the level of supra-aortic vessel ostia (p?<?0.0001) as well as along the brachiocephalic trunk (p?<?0.0001), the subclavian arteries (p?<?0.0001), proximal common carotid arteries (p?=?0.01), and vertebral V1 segments (p?<?0.0001). Using the high-pitch mode, the dose-length product was reduced by about 35 % (218.2?±?30 versus 141.8?±?20 mGy?×?cm).

Conclusions

Due to elimination of transmitted cardiac motion, high-pitch CTA of the neck improves image quality in the proximity of the aortic arch while significantly lowering radiation dose. The technique thus qualifies as a promising alternative to conventional spiral CTA and may be particularly useful for identification of ostial stenosis.     

Image quality of ultra-low radiation exposure coronary CT angiography with an effective dose <0.1 mSv using high-pitch spiral acquisition and raw data-based iterative reconstruction

Objectives

We evaluated the potential of prospectively ECG-triggered high-pitch spiral acquisition with low tube voltage and current in combination with iterative reconstruction to achieve coronary CT angiography with sufficient image quality at an effective dose below 0.1 mSv.

Methods

Contrast-enhanced coronary dual source CT angiography (2?×?128?×?0.6 mm, 80 kV, 50 mAs) in prospectively ECG-triggered high-pitch spiral acquisition mode was performed in 21 consecutive individuals (body weight <100 kg, heart rate ≤60/min). Images were reconstructed with raw data-based filtered back projection (FBP) and iterative reconstruction (IR). Image quality was assessed on a 4-point scale (1 = no artefacts, 4 = unevaluable).

Results

Mean effective dose was 0.06?±?0.01 mSv. Image noise was significantly reduced in IR (128.9?±?46.6 vs. 158.2?±?44.7 HU). The mean image quality score was lower for IR (1.9?±?1.1 vs. 2.2?±?1.0, P?<?0.0001). Of 292 coronary segments, 55 in FBP and 40 in IR (P?=?0.12) were graded “unevaluable”. In patients with a body weight ≤75 kg, both in FBP and in IR, the rates of fully evaluable segments were significantly higher in comparison to patients >75 kg.

Conclusions

Coronary CT angiography with an estimated effective dose <0.1 mSv may provide sufficient image quality in selected patients through the combination of high-pitch spiral acquisition and raw data-based iterative reconstruction.

Key Points

? Coronary CT angiography with an estimated effective dose <0.1 mSv is possible. ? Combination of high-pitch spiral acquisition with iterative reconstruction achieves sufficient image quality. ? Diagnostic accuracy remains to be assessed in future trials.     

Accuracy, image quality and radiation dose comparison of high-pitch spiral and sequential acquisition on 128-slice dual-source CT angiography in children with congenital heart disease

Objectives

To compare accuracy, image quality and radiation dose between high-pitch spiral and sequential modes on 128-slice dual-source computed tomographic (DSCT) angiography in children with congenital heart disease (CHD).

Methods

Forty patients suspected with CHD underwent 128-slice DSCT angiography with high-pitch mode and sequential mode respectively. All the anomalies were confirmed by the surgical and/or the conventional cardiac angiography (CCA) findings. The diagnostic accuracy, the subjective and objective image quality and effective radiation doses were compared.

Results

There was no significant difference in diagnostic accuracy (χ ² ?=?0.963, P?>?0.05), the objective parameters for image quality (P?>?0.05) and the image quality of great vessels (u?=?167.500, P?>?0.05) between the two groups. The image quality of intracardiac structures and coronary arteries was significantly better in the sequential mode group than that in the high-pitch group (u?=?112.500 and 100.000, P?t?=?5.287, P?Conclusions Both the high-pitch and the sequential modes for 128-slice DSCT angiography provide high accuracy for the assessment of CHD in children, while the high-pitch mode, even with some image quality decrease, further significantly lowers the radiation dose.

Key Points

? Modern CT provides excellent anatomical detail of congenital heart disease. ? Dual source CT systems offer high-pitch spiral and sequential modes. ? The high-pitch mode provides high accuracy for the assessment of CHD. ? A few images using the high-pitch mode were occasionally slightly degraded. ? But the high-pitch mode significantly lowers the radiation dose.