Patency of runoff detected by MR angiography at 3.0 T with cuff-compression: a predictor of successful endovascular recanalization below the knee

Objectives

Our aim was to assess the reliability of detecting distal runoff vessels using contrast-enhanced MR angiography (CE-MRA) that were occult on digital subtraction angiography (DSA) for predicting the outcome of endovascular recanalization (ER).

Methods

This retrospective analysis comprised 63 patients with diabetes (98 limbs) who underwent ER for infrapopliteal lesions. Before ER, they underwent CE-MRA and DSA for peripheral arterial disease; runoff vessels were detected with CE-MRA, but not with DSA. Immediate and follow-up postoperative outcomes were assessed. Univariate analysis was performed to identify variables associated with successful ER.

Results

Successful ER was achieved in 85.7 % of limbs, and runoff score was significantly lower than in failure limbs (5.1?±?1.1 vs. 6.2?±?1.3; P?Restenosis/occlusion rate was higher for patients with CLI at 12 months (48.8 % vs. 96.3 % in claudication; P?P?Conclusion Runoff vessels detected using CE-MRA could indicate immediate success and better outcome of ER for infrapopliteal occlusions.

Key Points

? 3-T MRA with cuff compression displayed distal below-the-knee (BTK) runoffs better than DSA ? Detected runoffs indicate high recanalization rate and good clinical outcome ? Runoff display provides potential opportunity to perform other backup recanalization strategies     

The accuracy and utility of contrast-enhanced MR angiography for localization of spinal dural arteriovenous fistulas: the Toronto experience

Objectives

The purpose of this study was to determine the accuracy and utility of contrast-enhanced MR angiography (CE-MRA) in spinal dural arteriovenous fistulas (SDAVF).

Methods

A retrospective analysis from 1999–2012 identified 70 patients clinically suspected of harboring a SDAVF. Each patient underwent consecutive conventional MR-imaging, CE-MRA, and digital subtraction angiography (DSA). The presence or absence of serpentine flow voids, T2-weighted hyperintensity, and cord enhancement were evaluated, as well as location of the fistula as predicted by CE-MRA. DSA was used as the reference standard.

Results

Of the 70 cases, 53 were determined to be a SDAVF, 10 cases were shown to be other forms of vascular malformation, and 7 were DSA-negative. On MRI, all reported cases of SDAVF showed serpentine flow voids (100 %). T2-weighted hyperintensity was seen in 48 of 50 cases (96 %), extending to the conus in 41 of 48 cases (85 %). Cord enhancement was seen in 38 of 41 cases (93 %). CE-MRA correctly localized the SDAVF in 43 of the 53 cases (81 %).

Conclusions

CE-MRA is a useful non-invasive examination for the detection and localization of SDAVF. CE-MRA facilitates but does not replace DSA as confirmation of location, fistula type, and arterial detail, which are required before treatment.

Key Points

? CE-MRA correctly localized the site of the SDAVF in over 80 % of cases. ? CE-MRA facilitates diagnostic DSA and expedites the diagnostic process. ? CE-MRA does not replace diagnostic DSA in SDAVF cases as confirmative test. ? CE-MRA provides better understanding of missed or mislocalized SDAVF cases.     

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.     

Hybrid CT angiography and quantitative 15O-water PET for assessment of coronary artery disease: comparison with quantitative coronary angiography

Purpose

CT angiography (CTA) can rule out significant stenoses with a very high reliability, whereas its ability to confirm significant stenoses is suboptimal. In contrast, measurements of myocardial blood flow (MBF) provide information on the haemodynamic consequences of stenoses. Therefore, a combination of the two might improve diagnostic accuracy. We conducted a head-to-head comparison of CTA, measurement of MBF by ¹⁵O-water PET, and hybrid PET/CTA for the detection of significant coronary artery stenoses.

Methods

The study group comprised 44 outpatients scheduled for invasive coronary angiography (ICA) with an intermediate pretest likelihood of coronary artery disease. The patients underwent 64-slice CTA and baseline and hyperaemic PET before ICA with quantitative coronary angiography analysis.

Results

On a per-patient basis, the negative predictive values (NPV; 95 % confidence intervals in parentheses) were 88 % (64 – 97 %) for CTA, 90 % (71 – 97%) for PET and 92 % (74 – 98%) for PET/CTA, and the positive predictive values (PPV) were 71 % (53 – 85%) for CTA, 87 % (68 – 95%) for PET and 100 % (84 – 100%) for PET/CTA. Similarly, on a per-vessel basis the NPVs (which were generally high) were 97 % (94 – 100%) for CTA, 95 % (90 – 99%) for PET and 97 % (95 – 100%) for PET/CTA, and the PPVs (which were lower, but higher with PET/CTA) were 53 % (39 – 66%) for CTA, 53 % (40 – 66%) for PET and 85 % (73 – 97%) for PET/CTA. In six patients, CTA analysis was hampered by the presence of severe calcifications. However, with the addition of the PET data, all six patients were correctly categorized.

Conclusion

Cardiac quantitative hybrid PET/CTA imaging has better diagnostic accuracy than CTA alone and PET alone. CTA has a suboptimal PPV, suggesting that hybrid PET/CTA imaging should be used to assess the significance of coronary stenoses diagnosed by CTA.     

Value of CT angiography for the detection of intracranial vascular lesions in patients with acute severe headache

Objectives

To retrospectively investigate the prevalence and characteristics of intracranial vascular lesions in patients with acute severe headache with the use of CT angiography (CTA).

Methods

We systematically searched for neurologically intact patients with acute severe headache and normal unenhanced head CT. The study group consisted of 512 patients; 251 male; mean age 46.2?±?12.4 years. All patients underwent CTA between 1 day and 2 months after the headache attack. CTA images were interpreted by two experienced neuroradiologists for the presence of vascular lesions.

Results

Thirty-four (6.6 %) of the 512 patients had intracranial vascular lesions on CTA, including 33 aneurysms (2 patients had 2 aneurysms each), 2 moyamoya disease and 1 arterial dissection. No gender- or age-related differences were found. Aneurysms arose most commonly on the internal carotid artery (n?=?12), followed by the anterior communicating artery (n?=?7), and the middle cerebral artery (n?=?7). Maximal diameters ranged from 2.0 to 13.1 mm (mean, 3.9?±?2.6 mm).

Conclusions

CTA is a feasible tool for diagnosing intracranial vascular lesions in patients with acute severe headache. The prevalence of vascular lesions in our series was 6.6 %, which is higher than that predicted in the general population.

Key Points

? Unruptured cerebral aneurysms may be a cause of acute severe headache ? CTA assesses intracranial vascular lesions in patients with acute severe headache ? The prevalence of vascular lesions in our series of patients was 6.6 %     

Follow-up of coiled intracranial aneurysms: comparison of 3D time-of-flight and contrast-enhanced magnetic resonance angiography at 3T in a large, prospective series

Objectives

To compare 3D-TOF magnetic resonance angiography (MRA) and contrast-enhanced MRA (CE-MRA) sequences at 3T in the follow-up of coiled aneurysms with digital subtracted angiography (DSA) as the gold standard.

Methods

DSA, 3D-TOF and CE-MRA were performed in a prospective series of 126 aneurysms in 96 patients (57 female, 39 male; age: 25–75 years, mean: 51.3?±?11.3 years). The quality of aneurysm occlusion was assessed independently and anonymously by a core laboratory.

Results

Using DSA (gold standard technique), total occlusion was depicted in 57 aneurysms (45.2%), neck remnant in 34 aneurysms (27.0%) and aneurysm remnant in 35 aneurysms (27.8%). Sensitivity, specificity, positive predictive value and negative predictive value were very similar with 3D-TOF and CE-MRA. Visibility of coils was much better with 3D-TOF (95.2%) than with CE-MRA (23.0%) (P?P?=?0.012).

Conclusions

In this large prospective series of patients with coiled aneurysms, at 3T 3D-TOF MRA was equivalent to CE-MRA for the evaluation of aneurysm occlusion, but coil visibility was superior at 3D-TOF. Thus the use of 3D-TOF at 3T is recommended for the follow-up of coiled intracranial aneurysms.

Key Points

? Different Magnetic Resonance (MR) imaging techniques are used to evaluate intracranial aneurysms. ? At 3T MR, 3D-TOF and CE-MRA appear equivalent for evaluating coiled aneurysms.. ? Coils are better visualised on 3D-TOF than on CE-MRA. ? Combined analysis of 3D-TOF and CE-MRA does not seem helpful. ? At 3T, 3D-TOF techniques are recommended for monitoring patients with coiled aneurysms.     

Subtraction CT angiography for the diagnosis of iliac arterial steno-occlusive disease

Purpose

Accurate evaluation of stenosis in severely calcified arteries is a major challenge in conventional CT angiography (CTA) for peripheral arterial disease (PAD). The aim of this study was to evaluate the efficacy of subtraction CTA compared with conventional CTA and conventional angiography.

Materials and methods

175 arterial segments of 31 consecutive patients with PAD who underwent CTA and subsequent digital subtraction angiography (DSA) were evaluated. The percentage stenosis of diseased arteries was measured in iliac arteries with caliper methods on conventional CTA and subtraction CTA, and the concordance of each CTA method with DSA in the identification of >50 % stenosis was evaluated. Interpretation of CTA was always based only on maximum intensity projection (MIP).

Results

174 (99 %) segments were interpretable on subtraction CTA and showed a good correlation with DSA (R ² = 0.844), although 55 (31 %) segments were not evaluable on conventional CTA due to severe calcification. On subtraction CTA, the segmental accuracy, sensitivity, and specificity were 90.5, 78.9, and 80.0 %, respectively.

Conclusion

Subtraction CTA is an accurate diagnostic tool for the evaluation of PAD. It may be easier to interpret stenosis in the presence of calcifications using subtraction CTA rather than with the conventional CTA approach. Also, subtraction CTA using only MIP presented a similar accuracy to DSA.

     

Clinical evaluation of automatic tube voltage selection in chest CT angiography

Objective

To evaluate the clinical impact of automatic tube voltage selection on chest CT angiography (CTA).

Methods

Ninety-three patients were prospectively evaluated with a CT protocol aimed at comparing two successive CTAs acquired under similar technical conditions except for the kV selection: (1) the initial CTA was systematically obtained at 120 kVp and 90 ref mAs; (2) the follow-up CTA was obtained with an automatic selection of the kilovoltage (Care KV; Siemens Healthcare) for optimised CTA.

Results

At follow-up, 90 patients (97 %) underwent CTA with reduced tube voltage, 100 kV (n?=?26; 28 %) and 80 kV (n?=?64; 69 %), resulting in a significant dose-length-product reduction (follow-up: 87.27; initial: 141.88 mGy.cm; P?<?0.0001; mean dose reduction: 38.5 %) and a significant increase in the CNR at follow-up (follow-up: 11.5?±?3.5 HU; initial: 10.9?±?3.7 HU; P?=?0.03). The increase in objective image noise at follow-up (follow-up: 23.2?±?6.7 HU vs. 17.8?±?5.1 HU; P?<?0.0001) did not alter the diagnostic value of images.

Conclusion

Automatic tube voltage selection reduced the radiation dose delivered during chest CT angiograms by 38.5 % while improving the contrast-to-noise ratio of the examinations.

Key Points

? As low a dose as possible must be used for CT angiography. ? Automatic tube voltage selection permits reduced patient exposure. ? Lowering the kVp enables increased intravascular attenuation. ? Automatic tube voltage selection does not compromise the overall image quality.     

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     

3D non-contrast-enhanced ECG-gated MR angiography of the lower extremities with dual-source radiofrequency transmission at 3.0 T: Intraindividual comparison with contrast-enhanced MR angiography in PAOD patients

Objective

To compare prospectively image quality and diagnostic confidence of flow-sensitive 3D turbo spin echo (TSE)-based non-contrast-enhanced MR angiography (NE-MRA) at 3.0 T using dual-source radiofrequency (RF) transmission with contrast-enhanced MRA (CE-MRA) in patients with peripheral arterial occlusive disease (PAOD).

Methods

After consent was obtained, 35 patients (mean age 69.1?±?10.6 years) with PAOD stage II-IV underwent NE-MRA followed by CE-MRA. Signal-to-noise ratio and contrast-to-noise ratio were calculated. Subjective image quality was independently assessed by two radiologists and stenosis scoring was performed in 875 arterial segments. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for stenosis classification were calculated using CE-MRA as a reference method. Diagnostic agreement with CE-MRA was evaluated with Cohen’s kappa statistics.

Results

NE-MRA provided high objective and subjective image quality at all levels of the arterial tree. Sensitivity and specificity for the detection of relevant stenosis was 91 % and 89 %, respectively; the NPV was 96 % and the PPV 78 %. There was good concordance between CE-MRA and NE-MRA in stenosis scoring.

Conclusions

3D electrocardiography (ECG)-gated TSE NE-MRA with patient-adaptive dual-source RF transmission at 3.0 T is a promising alternative for PAOD patients with contraindications for gadolinium-based contrast agents. It offers high sensitivity and NPV values in the detection of clinically relevant arterial stenosis.

Key points

? Flow-sensitive TSE NE-MRA is a promising technique for PAOD evaluation.? Diagnostic accuracy is comparable to contrast-enhanced MRA.? NE-MRA eliminates the risk of NSF in patients with renal insufficiency.? Costs arising from the use of contrast agents can be avoided.

     

Optimal table feed in run-off CT angiography in patients with abdominal aortic aneurysms

Objectives

To assess the influence of different table feeds (TFs) on vascular enhancement and image quality in patients with an abdominal aortic aneurysm (AAA) undergoing computed tomography (CT) angiography of the lower extremities (run-off CTA).

Methods

Seventy-nine patients (71?±?8 years) with an AAA (>30 mm) who underwent run-off CTA between January 2004 and August 2011 were included in this retrospective institutional review board-approved study. Run-off CTA was conducted using 16- and 64-row CT. The range of TFs was 30–86 mm/s and was categorised in quartiles TF1 (32.6?±?1.9 mm/s), TF2 (38.9?±?0.9 mm/s), TF3 (43.9?±?3.1 mm/s) and TF4 (57.4?±?10.5 mm/s). Image quality was rated independently by two radiologists and vessel enhancement was assessed.

Results

Image quality was diagnostic at all aortic, pelvic and almost all thigh levels. Below the knee, the number of diagnostic levels was highest for TF1 and decreased to TF4. Arterial enhancement between the aorta and fibular trunk was not different in all TF groups, P?>?0.05. At the calf and foot strongest arterial enhancement was noted for TF1 and TF2 and decreased to TF4, P?<?0.01.

Conclusion

Results indicate that the highest image quality of run-off CTA in patients with an AAA may be obtained using table feeds measuring 30–35 mm/s.

Key Points

? CTA has become a key investigation for peripheral vascular disease. ? Run-off CTA is more complex in patients with an abdominal aortic aneurysm. ? Run-off CTA is feasible with a short bolus of intravenous contrast medium. ? A constant 30–35 mm/s table feed provides the highest likelihood of diagnostic images.     

Low tube voltage and low contrast material volume cerebral CT angiography

Objectives

To evaluate the image quality, radiation dose and diagnostic accuracy of low kVp and low contrast material volume cerebral CT angiography (CTA) in intracranial aneurysm detection.

Methods

One hundred twenty patients were randomly divided into three groups (n?=?40 for each): Group A, 70 ml iodinated contrast agent/120 kVp; group B, 30 ml/100 kVp; group C, 30 ml/80 kVp. The CT numbers, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured in the internal carotid artery (ICA) and middle cerebral artery (MCA). Subjective image quality was evaluated. For patients undergoing DSA, diagnostic accuracy of CTA was calculated with DSA as reference standard and compared.

Results

CT numbers of ICA and MCA were higher in groups B and C than in group A (P?<?0.01). SNR and CNR in groups A and B were higher than in group C (both P?<?0.05). There was no difference in subjective image quality among the three groups (P?=?0.939). Diagnostic accuracy for aneurysm detection among these groups had no statistical difference (P?=?1.00). Compared with group A, the radiation dose of groups B and C was decreased by 45 % and 74 %.

Conclusion

Cerebral CTA at 100 or 80 kVp using 30 ml contrast agent can obtain diagnostic image quality with a low radiation dose while maintaining the same diagnostic accuracy for aneurysm detection.

Key Points

? Cerebral CTA is feasible using 100/80 kVp and 30 ml contrast agent. ? This approach obtains diagnostic image quality with 45–74 % radiation dose reduction. ? Diagnostic accuracy for intracranial aneurysm detection seems not to be compromised.     

Assessment of vascular invasion by bone and soft tissue tumours of the limbs: usefulness of MDCT angiography

Objective

To evaluate the accuracy of computed tomography angiography (CTA) in predicting arterial encasement by limb tumours, by comparing CTA with surgical findings (gold standard).

Methods

Preoperative CTA images of 55 arteries in 48 patients were assessed for arterial status: cross-sectional CTA images were scored as showing a fat plane between artery and tumour (score 0), slight contact between artery and tumour (score 1), partial arterial encasement (score 2) or total arterial encasement (score 3). Reformatted CTA images were assessed for arterial displacement, rigid wall, stenosis or occlusion. At surgery, arteries were classified as free or surgically encased; 45 arteries were free and 10 were surgically encased.

Results

Multivariate logistic regression identified the axial CTA score as a relevant predictor for arterial encasement and subsequent vascular intervention during surgery. All sites where CTA showed a fat plane between the tumour and the artery were classified as free at surgery (n?=?28/28). The sensitivity of total arterial encasement on CTA (score 3) was 90%, specificity 93%, accuracy 93% and positive likelihood ratio 13.5.

Conclusion

CTA evidence of total arterial encasement is a highly specific indication of arterial encasement. The presence of fat between the tumour and the artery on CTA rules out arterial involvement at surgery.     

3D FIESTA pulse sequence for assessing renal artery stenosis: is it a reliable application in unenhanced magnetic resonance angiography?

Objectives

To assess the capability of the three-dimensional (3D) Fast Imaging Employing Steady-State Acquisition (FIESTA) sequence in evaluating renal artery stenosis (RAS).

Methods

We retrospectively analysed 79 patients referred for suspected RAS, examined by 3D FIESTA and contrast-enhanced magnetic resonance angiography (CE-MRA), using a 1.5T whole-body scanner. Image quality was assessed as well as the presence and grade of RAS. Patients with RAS?≥?50 % were evaluated for possible digital subtraction angiography (DSA). Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy of 3D FIESTA were calculated with ROC analysis using CE-MRA and DSA as the standard of reference.

Results

A total of 186 renal arteries were assessed; 36 had RAS?≥?50 % demonstrated by CE-MRA. Ten patients underwent DSA, for a total evaluation of 22 arteries. Sensitivity, specificity, NPV, PPV, and accuracy of 3D FIESTA were 91.7 %, 100 %, 98 %, 100 %, and 98 %, respectively, as compared to CE-MRA, and 88.2 %, 100 %, 71.4 %, 100 %, and 91 %, respectively, as compared to DSA. The area under the ROC curve (AUC) of 3D FIESTA as compared to CE-MRA and DSA was 0.958 and 0.941, respectively.

Conclusions

Our study demonstrated the capability of the 3D FIESTA sequence in evaluating RAS, with high-quality images and good diagnostic accuracy.

Key Points

? The 3D FIESTA sequence provides a robust evaluation of RAS. ? The 3D FIESTA sequence allows non-invasive evaluation of the renal arteries. ? The 3D FIESTA sequence could be a useful tool in evaluating RAS.     

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.     

Planning deep inferior epigastric perforator flaps for breast reconstruction: a comparison between multidetector computed tomography and magnetic resonance angiography

Objectives

Deep inferior epigastric perforator (DIEP) flaps have become the state of the art in breast reconstruction. We compared the diagnostic performance of multidetector computed tomography (CTA) and magnetic resonance angiography (MRA) in DIEP flap planning.

Methods

Twenty-three women (mean age 48.0 years, range 26–72 years) underwent preoperative blinded evaluation using 64-slice CTA and 1.5-T MRA. Perforator identification, measurement of their calibre, intramuscular course (IMC), assessment of direct venous connections (DVC) with main superficial veins, superficial venous communications (SVC) between the right and left hemi-abdomen and deep inferior epigastric artery (DIEA) branching type were performed. Surgery was carried out by the same team. Intraoperative findings were the standard of reference.

Results

Accuracy in identifying dominant perforators was 91.3 % for both techniques and mean error in calibre measurement 1.18?±?0.35 mm for CTA and 1.63?±?0.39 mm for MRA. Accuracy in assessing perforator IMCs was 97.1 % for CTA and 88.4 % for MRA, DVC 94.4 % for both techniques, SVC 91.3 % as well, and DIEA branching type 100 % for CTA and 91.3 % for MRA. Image acquisition and interpretation time was 21?±?3 min for CTA (35?±?5 min for MRA).

Conclusions

In a strategy to optimise DIEP flap planning avoiding radiation exposure, MRA can be proposed alternatively to CTA.

Key points

? Identification of deep inferior epigastric perforators (DIEP) is important before breast reconstruction. ? Both CT and MR angiography are accurate in identifying DIEA perforator branches. ? CTA and MRA are equivalent in demonstrating perforator-venous connections. ? MRA can be proposed as an alternative to CTA in DIEP planning.     

Diagnostic accuracy of combined coronary angiography and adenosine stress myocardial perfusion imaging using 320-detector computed tomography: pilot study

Objectives

To determine the diagnostic accuracy of combined 320-detector row computed tomography coronary angiography (CTA) and adenosine stress CT myocardial perfusion imaging (CTP) in detecting perfusion abnormalities caused by obstructive coronary artery disease (CAD).

Methods

Twenty patients with suspected CAD who underwent initial investigation with single-photon-emission computed tomography myocardial perfusion imaging (SPECT-MPI) were recruited and underwent prospectively-gated 320-detector CTA/CTP and invasive angiography. Two blinded cardiologists evaluated invasive angiography images quantitatively (QCA). A blinded nuclear physician analysed SPECT-MPI images for fixed and reversible perfusion defects. Two blinded cardiologists assessed CTA/CTP studies qualitatively. Vessels/territories with both >50 % stenosis on QCA and corresponding perfusion defect on SPECT-MPI were defined as ischaemic and formed the reference standard.

Results

All patients completed the CTA/CTP protocol with diagnostic image quality. Of 60 vessels/territories, 17 (28 %) were ischaemic according to QCA/SPECT-MPI criteria. Sensitivity, specificity, PPV, NPV and area under the ROC curve for CTA/CTP was 94 %, 98 %, 94 %, 98 % and 0.96 (P?<?0.001) on a per-vessel/territory basis. Mean CTA/CTP radiation dose was 9.2?±?7.4 mSv compared with 13.2?±?2.2 mSv for SPECT-MPI (P?<?0.001).

Conclusions

Combined 320-detector CTA/CTP is accurate in identifying obstructive CAD causing perfusion abnormalities compared with combined QCA/SPECT-MPI, achieved with lower radiation dose than SPECT-MPI.

Key Points

? Advances in CT technology provides comprehensive anatomical and functional cardiac information. ? Combined 320-detector CTA/adenosine-stress CTP is feasible with excellent image quality. ? Combined CTA/CTP is accurate in identifying myocardial ischaemia compared with QCA/SPECT-MPI. ? Combined CTA/CTP results in lower patient radiation exposure than SPECT-MPI. ? CTA/CTP may become an established imaging technique for suspected CAD.     

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.     

Agreement between SPECT V/Q scan and CT angiography in patients with high clinical suspicion of PE

Objective

To track agreement between single positron emission computed tomography (SPECT) V/Q and CT angiography in patients with high clinical suspicion of pulmonary embolism (PE). If significant agreement occurs, a case could be made for more frequent use of chest radiography followed by SPECT V/Q scanning given its lower risk profile.

Introduction

Diagnosis of PE can be difficult. CT pulmonary angiography (CTA) is the preferred initial test, but may be indeterminate, is a significant source of ionizing radiation, and is contraindicated in renal insufficiency. SPECT ventilation/perfusion imaging (V/Q) is therefore preferred in certain patients.

Methods

Two thousand nine hundred and twenty patients admitted to a tertiary care hospital in New York City were screened and 100 consecutive high-risk patients who required both CTA and V/Q for an initial indeterminate or negative imaging test despite a high pre-test probability were identified. The agreement between these tests was evaluated.

Results

There was no significant agreement between CTA and V/Q when positive, negative and indeterminate results were included (K = 0.18, SE = 0.09, p = 0.051). However, in the presence of a positive finding on either test, there was substantial agreement between the two (K = 0.62, SE = 0.27, p = 0.02). In 30 cases in which CTA was indeterminate, V/Q was diagnostic 93 % of the time. In 12 cases in which V/Q was indeterminate, CTA was diagnostic 83 % of the time and negative in 100 % of those cases.

Conclusion

In the presence of an indeterminate CTA in patients with high clinical suspicion of PE, SPECT V/Q often provides a diagnosis.     

Relationship between vertebral artery hypoplasia and posterior circulation stroke in Chinese patients

Introduction

Vertebral artery hypoplasia (VAH), which has been found in about 10 % of normal individuals, does not produce symptoms but may be associated with an increased risk of cerebral posterior circulation ischemic (PCI) stroke. The aims of this study were to determine the prevalence of VAH in Chinese patients with cerebral infarction and investigate whether VAH is an independent risk factor for PCI stroke.

Methods

The medical records of 841 Chinese stroke patients were reviewed retrospectively. All patients underwent either cervical contrast-enhanced magnetic resonance angiography (CE-MRA) or cervical computed tomography angiography (CTA). There is no standard definition of VAH; we defined it as a vertebral artery <2 mm in diameter and the whole artery was slim or absent on CE-MRA or CTA. Univariate and multivariate logistic regression analyses were performed to identify significant independent risk factors for PCI stroke.

Results

There were 230 patients (27.3 %) diagnosed with PCI stroke and 91 patients diagnosed with VAH (10.8 %). Multivariate logistic regression analysis showed that VAH, male gender, and stenosis of the posterior circulation were independent risk factors for PCI stroke.

Conclusions

Our results show that VAH is not rare in Chinese patients with stroke and that its presence increases the risk of PCI stroke.