Volumetric Computed Tomography Angiography Research Articles

Dynamic Volumetric Computed Tomography Angiography is an Effective Method to Evaluate Tracheomalacia in Children.

Standard methods to evaluate tracheal pathology in children, including bronchoscopy, may require general anesthesia. Conventional dynamic proximal airway imaging in noncooperative children requires endotracheal intubation and/or medically induced apnea, which may affect airway mechanics and diagnostic performance. We describe a technique for unsedated dynamic volumetric computed tomography angiography (DV-CTA) of the proximal airway and surrounding vasculature in children and evaluate its performance compared to the reference-standard of rigid bronchoscopy. Children who had undergone DV-CTA and bronchoscopy in one-year were retrospectively identified. Imaging studies were reviewed by an expert reader blinded to the bronchoscopy findings of primary or secondary tracheomalacia. Airway narrowing, if present, was characterized as static and/or dynamic, with tracheomalacia defined as >50% collapse of the tracheal cross-sectional area in exhalation. Pearson correlation was used for comparison. Over a 19-month period, we identified 32 children (median age 8 months, range 3-14 months) who had undergone DV-CTA and bronchoscopy within a 90-day period of each other. All studies were unsedated and free-breathing. The primary reasons for evaluation included noisy breathing, stridor, and screening for tracheomalacia. There was excellent agreement between DV-CTA and bronchoscopy for diagnosis of tracheomalacia (κ=0.81, p < 0.001), which improved if children (n=25) had the studies within 30 days of each other (κ=0.91, p < 0.001). CTA provided incremental information on severity, and cause of secondary tracheomalacia. For most children, DV-CTA requires no sedation or respiratory manipulation and correlates strongly with bronchoscopy for the diagnosis of tracheomalacia. 3 Laryngoscope, 133:410-416, 2023.

Fabric Tears and Type IIIb Endoleaks After Fenestrated-Branched Endovascular Aortic Aneurysm Repair

Type IIIb endoleaks from fabric tears after fenestrated-branched endovascular aortic aneurysm repair (F-BEVAR) are rare. The aim of this study was to evaluate patients who had undergone F-BEVAR with investigational devices between 2015 and 2021 in our institution. A total of 268 patients who had undergone F-BEVAR between 2015 and 2021 were analyzed. All patients with type IIIb endoleaks were included in the data collection. The end points were presentation of type IIIb endoleaks and secondary interventions. Three patients had developed type IIIb endoleaks (2 women and 1 man; mean age, 75 years). The first patient was a 74-year-old woman who had undergone F-BEVAR for a thoracoabdominal aortic aneurysm with a device with two branches and two fenestrations. The 4-year postoperative computed tomography angiography (CTA) demonstrated an endoleak behind the branches, which was confirmed to be a fabric tear using dynamic volumetric CTA (Fig 1, A). The patient underwent successful redo F-BEVAR. The second patient was a 74-year-old woman who had undergone branched repair with a device with four branches and an inverted limb bifurcated device after failed endovascular repair. On the 30-day follow-up CTA, an endoleak of indeterminate origin was detected. Further imaging studies, including CTA, dynamic volumetric CTA, and diagnostic angiography confirmed a tear in the graft posterior to a renal branch (Fig 1, B). A redo branched repair was successfully performed. The last patient was a 78-year-old man who had undergone four-vessel F-BEVAR with an inverted limb custom-made device after failed endovascular repair. On the 30-day follow-up visit, a type IIIb endoleak around the crutch of the inverted limb device was identified by CTA, contrast-enhanced ultrasound, and color-Doppler ultrasound (Fig 2). The defect was excluded with an iliac limb extension. Technical success of the reinterventions was 100%, with no deaths. Sac growth before reintervention was identified in all three patients. The mean follow-up was 30 months. Endoleak development had occurred at an average of 17 months after the index operation. The overall frequency of type IIIb endoleaks in our series was 1.1%. Type IIIb endoleaks after F-BEVAR are rare. The management of these cases is technically challenging. Proper multimodality imaging and redo F-BEVAR are crucial for the proper diagnosis and treatment of this rare complication.Fig 2Endoleak around the crutch of inverted limb custom-made device.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Dynamic Volumetric Computed Tomography Angiography Is a Preferred Method for Unclassified Endoleaks by Conventional Computed Tomography Angiography After Endovascular Aortic Repair.

BackgroundThe aim of this study was to assess the feasibility and safety of dynamic volumetric computed tomography angiography (DV‐CTA) for endoleaks detected but not classified by conventional CTA in patients after endovascular aortic repair.Methods and ResultsFrom January 2016 to October 2017, 24 patients with endoleaks with aneurysm sac enlargement detected but not classified by conventional CTA were randomly assigned to the conventional CTA group and the DV‐CTA group for further evaluation. The amount of contrast agent, radiation dosage, and changes in creatinine during the operation were compared between the 2 groups. Reintervention was performed according to the endoleak classification followed by the 6‐ and 12‐month follow‐up. The accuracy of classifying endoleaks by DV‐CTA was comparable to that by digital subtraction angiography. Additionally, the total amount of contrast agent and the radiation dosage in the DV‐CTA group during the operation were diminished by 14.0% (P=0.007) and 12.1% (P=0.004), respectively, compared with those in the conventional CTA group. No contrast‐induced nephropathy was observed. All endoleaks were treated instantly after identification. No endoleaks were found in any of the patients during follow‐up.Conclusions DV‐CTA could replace digital subtraction angiography as an alternative method for the classification of endoleaks that cannot be differentiated by conventional CTA. Additionally, the amount of contrast agent and the total radiation dosage were substantially reduced, which improved safety among operators and patients.

Interleaving cerebral CT perfusion with neck CT angiography. Part II: clinical implementation and image quality

ObjectivesFeasibility evaluation of the One-Step Stroke Protocol, which is an interleaved cerebral computed tomography perfusion (CTP) and neck volumetric computed tomography angiography (vCTA) scanning technique using wide-detector computed tomography, and to assess the image quality of vCTA.MethodsTwenty patients with suspicion of acute ischaemic stroke were prospectively scanned and evaluated with a head and neck CTA and with the One-Step Stroke Protocol. Arterial enhancement and contrast-to-noise ratio (CNR) in the carotid arteries was assessed. Three observers scored artefacts and image quality of the cervical arteries. The total z-coverage was evaluated.ResultsMean enhancement in the carotid bifurcation was rated higher in the vCTA (595 ± 164 HU) than CTA (441 ± 117 HU). CNR was rated higher in vCTA. Image quality scores showed no significant difference in the region of the carotid bifurcation between vCTA and CTA. Lower neck image quality scores were slightly lower for vCTA due to artefacts, although not rated as diagnostically relevant. In ten patients, the origin of the left common carotid artery was missed by 1.6 ± 0.8 cm. Mean patient height was 1.8 ± 0.09 m. Carotid bifurcation and origin of vertebral arteries were covered in all patients.ConclusionsThe One-Step Stroke Protocol is feasible with good diagnostic image quality of vCTA, although full z-coverage is limited in tall patients.Key Points• Interleaving cerebral CTP with neck CTA (One-Step Stroke Protocol) is feasible• Diagnostic quality of One-Step Stroke Protocol neck CTA is similar to conventional CTA• One-Step Stroke Protocol neck CTA suffers from streak artefacts in the lower neck• A limitation of One-Step Stroke Protocol CTA is lack of coverage in tall patients• Precise planning of One-Step Stroke Protocol neck CTA is necessary in tall patients

Diagnosis and Treatment of Intracranial Aneurysms with 320-Detector Row Volumetric Computed Tomography Angiography

The objective of the study was to determine the clinical utility of 320-detector row volume-computed tomographic angiography (VCTA) in the management of intracranial aneurysms. Between February 2011 and May 2015, 550 patients successfully underwent 320-detector row VCTA for suspected intracranial aneurysms. Three-dimensional (3D) digital subtraction angiography (DSA) was used as the ultimate reference standard, and the sensitivity, specificity, and accuracy of both nonsubtracted and subtracted VCTA in identifying aneurysms were analyzed. Nonsubtracted VCTA identified 417 aneurysms (2 false-positive readings, 12 false-negative readings). The diagnostic sensitivity, specificity, and accuracy of non-subtracted VCTA, on a per-aneurysm basis, were 97.2%, 99.0%, and 97.6%, respectively. Subtracted VCTA identified 426 aneurysms (2 false-positive readings, 3 false-negative readings). The sensitivity, specificity, and accuracy of subtracted VCTA, on a per-aneurysm basis, were 99.3%, 99.0%, and 99.2%, respectively. No differences in diagnostic accuracy were found between subtracted VCTA and 3D DSA. Nonsubtracted VCTA, however, was observed to be significantly less sensitive than 3D DSA and subtracted VCTA. Twenty-six aneurysm cases were referred for surgical treatment based on VCTA imaging. All aneurysms were deemed completely occluded during surgical clipping. On the basis of VCTA imaging, 299 aneurysms were found suitable for endovascular coiling, of which 293 aneurysms (98%) were treated successfully. The 320-detector row subtracted VCTA technique is an effective, first-line diagnostic imaging modality for surgical and endovascular treatment of aneurysms. The nonsubtracted VCTA was less accurate than the subtracted VCTA, especially for intracranial aneurysms adjoining bone tissue.

A Comparison of Two-Dimensional CTA and Three-Dimensional Volumetric CTA Analysis Software Algorithms for Planning Thoracic, Thoracoabdominal, and Infrarenal Aortic Aneurysm Repair

This study compared relevant measurements in two-dimensional (2D) computed tomography angiography (CTA) imaging and semiautomated algorithmic measurements using 3D Volumetric CTA Interpretation software for thoracic, thoracoabdominal, and infrarenal aortic aneurysms. This retrospective study compared data points in 20 patients who underwent standard 2D CTA imaging and 3D CTA Interpretative software imaging for aortic aneurysmal disease. Information gathered was intended for preoperative planning and potential endovascular options. Measurements taken within the 3D CTA Interpretation software was done via a point-and-click method whereby the software algorithmically determines measurements along the aorta and displays them when the region of interest is selected. The software also determines the distance between two points using a centerline through the aorta as a reference. Intraluminal surface irregularities and location of thrombus is determined by direct observation via “drive through” techniques. Standard measurements were taken to include diameter of normal artery proximal and distal, length of neck, and landing zone. Additional criteria were evaluated for all aneurysm types including the presence of a normal artery, intraluminal defects, percentage of thrombus in the neck, and degree of calcification. From the 20 patients in our cohort, we obtained 20 contemporary imaging examination pairs. Bland-Altman analysis was performed and demonstrated that the 2D and 3D mean difference measurements was 0.8 mm. All data groups fell within two standard deviations with a range of 1.96 mm. Intraluminal abnormalities and more accurate vessel wall morphology were obtained with 3D imaging. The accuracy of 3D Volumetric CTA Analysis Software Algorithms in evaluating aneurysmal aortic disease for the purpose of preoperative planning is comparable to that of 2D CTA imaging and frequently provides helpful luminal surface information in preparation of repair.

Dynamic Volumetric CT Angiography for the Detection and Classification of Endoleaks: Application of Cine Imaging Using a 320-Row CT Scanner with 16-cm Detectors

PurposeTo assess the feasibility and diagnostic performance of dynamic volumetric computed tomography (CT) angiography with large-area detectors in the detection and classification of endoleaks after endovascular aneurysm repair (EVAR). Materials and MethodsLow-dose dynamic volumetric CT angiography performed with the patient in Fowler position was used to scan the entire stent graft with a 16-cm-area detector during the first follow-up examination after EVAR. There were 39 consecutive patients (36 men and 3 women; mean age, 74 y ± 8.7) examined with approximately 14–20 intermittent scans (temporal resolution, 2 s; scan range, 160 mm). The effective radiation dose, image quality, interobserver and intraobserver agreement for endoleak detection, and time delay between peak enhancement of the aorta and endoleaks were evaluated. ResultsAll examinations with the patient in Fowler position enabled the entire stent graft to be scanned and were rated as diagnostic. The mean effective radiation dose was 13.1 mSv. Endoleaks were detected in eight patients (type Ia, n = 1; type II, n = 6; type III, n = 1). Interobserver agreement (κ = 0.794) and intraobserver agreement (κ = 1.00) for detection of endoleaks were excellent. The mean time delay between peak enhancement of the aorta and the endoleaks was significantly less for type I/III endoleaks (2.0 s ± 0) compared with type II endoleaks (5.3 s ± 1.0; P < .001). ConclusionsLow-dose dynamic volumetric CT angiography performed with the patient in Fowler position is feasible after EVAR. Dynamic information, including cine imaging, the timing of peak enhancement, and the Hounsfield units index, is useful in detecting and classifying endoleaks.

Real time exploration and management of large medical volumetric datasets on small mobile devices—Evaluation of remote volume rendering approach

In this paper I present the architecture of system that can be used for real time exploration and management of large medical volumetric datasets. The new state of the art solution presented in this paper is an example of visual data management system. System prototype evaluation proved that it is possible to use low-powered (and cheap) up-to-date mobile devices with programmable GPUs as the remote interfaces for exploration of large volumetric medical data. The implementation was done with high-level programming language that enables portability between different hardware models. The lack of lossy compression enables to display high quality medical images visualizations without any simplifications and noises in frequency domain. The prototype of system is capable to remotely render and send to a client (for example cell phone or tablet) rendered data with frequency 30fps with limited resolution during interaction. One second after the interaction is finished client machine receives full resolution image. The evaluation of the system was performed on volumetric computed tomography angiography image with approximate size 5123voxels.

Image fusion for hybrid repair of dislocated superior mesenteric branch of a branched endovascular aortic graft

Recent advances in imaging technology allow the projection of volumetric imaging data from the preacquired computed tomography angiography over live fluoroscopy during interventions. This "fusion" technology is currently underused, although its application carries distinct advantages. We introduce a case in which fusion technology was used for the placement of two thoracic and one branched abdominal aortic endograft and to treat late dislocation of its side branch using a hybrid technique.

Volumetric Computed Tomography Angiography in the Evaluation of Mediastinal Fluid Collections following Congenital Cardiac Surgery

We present 3 patients with 4 causes of mediastinal fluid collection after congenital cardiac surgery in this extended case report. Volumetric computed tomography played an essential role in diagnosing causes and extent, relevant to subsequent management. Recent advances in volumetric computed tomography allow fast and accurate imaging of cardiovascular and extravascular structures in children with acceptable radiation dose, providing a powerful imaging tool for the evaluation of complications after congenital cardiac surgery.