Detection of ≥50% diameter stenosis left main coronary artery disease (LMD) has prognostic and therapeutic implications. Noninvasive stress imaging or an exercise tolerance test (ETT) are the most ...common methods to detect obstructive coronary artery disease, though stress test markers of LMD remain ill-defined.
The authors sought to identify markers of LMD as detected on coronary computed tomography angiography (CTA), using clinical and stress testing parameters.
This was a post hoc analysis of ISCHEMIA (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches), including randomized and nonrandomized participants who had locally determined moderate or severe ischemia on nonimaging ETT, stress nuclear myocardial perfusion imaging, or stress echocardiography followed by CTA to exclude LMD. Stress tests were read by core laboratories. Prior coronary artery bypass grafting was an exclusion. In a stepped multivariate model, the authors identified predictors of LMD, first without and then with stress testing parameters.
Among 5,146 participants (mean age 63 years, 74% male), 414 (8%) had LMD. Predictors of LMD were older age (P < 0.001), male sex (P < 0.01), absence of prior myocardial infarction (P < 0.009), transient ischemic dilation of the left ventricle on stress echocardiography (P = 0.05), magnitude of ST-segment depression on ETT (P = 0.004), and peak metabolic equivalents achieved on ETT (P = 0.001). The models were weakly predictive of LMD (C-index 0.643 and 0.684).
In patients with moderate or severe ischemia, clinical and stress testing parameters were weakly predictive of LMD on CTA. For most patients with moderate or severe ischemia, anatomical imaging is needed to rule out LMD. (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches ISCHEMIA; NCT01471522)
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Introduction
Pelvic lymphadenectomy (PL) causes changes to the inguinal lymph nodes with progressive loss of immune and lymphatic pump function. Efferent lymphatic vessel‐to‐venous anastomosis (ELVA) ...has been reported to address this problem. The aim of this report was to describe the feasibility of the SPECT/CT combined with ultrasound fusion imaging (UFI) to target the groin efferent lymph node (GELN) for ELVA.
Patients and Methods
Twelve patients with lower limb lymphedema after PL were scheduled for peripheric lymphaticovenular anastomosis (LVA) combined with ELVA. All‐patients were clinically ISL‐stage1, with good visualization of the inguinal lymph nodes at preoperative lymphoscintigraphy. The mean patient age was 55.4 years and the mean BMI was 25.5.The mean limb circumference (MLC) was calculated before surgery and 1 year after surgery. The LymQoL‐Leg questionnaire was administered before surgery and 6 months after surgery. Before surgery, the GELN was identified by SPECT/CT and its location was marked on the skin by UFI virtual navigation. Peripheric LVA sites were planned by ultrasound and indocyanine green (ICG) lymphography. Pre and postoperative MLC and LymQoL‐Leg scores were compared.
Results
In all‐patients, the SPECT/CT succeeded at detecting and targeting the GELN. In all‐patients, real‐time anatomical coregistration with US was feasible, and it was possible to mark on the groin skin the depth and position of the GELN on the skin at the groin. During surgery, in every patient, we found the GELN marked before surgery and performed ELVA. We also performed two or three peripheric LVAs in every patient. The mean value of MLC decreased (38.2 ± 2.13 cm vs. 36.33 ± 2.14 cm; p = .04) and the mean score of the LymQoL‐Leg questionnaire improved (9.3 ± 1.7 vs. 7.7 ± 1.1; p = .02).
Conclusion
SPECT/CT combined with UFI is feasible for the preoperative identification of GELN for ELVA.
Objectives
To assess the impact on image quality and dose reduction of a new deep learning image reconstruction (DLIR) algorithm compared with a hybrid iterative reconstruction (IR) algorithm.
...Methods
Data acquisitions were performed at seven dose levels (CTDI
vol
: 15/10/7.5/5/2.5/1/0.5 mGy) using a standard phantom designed for image quality assessment. Raw data were reconstructed using the filtered back projection (FBP), two levels of IR (ASiR-V50% (AV50); ASiR-V100% (AV100)), and three levels of DLIR (TrueFidelity™ low, medium, high). Noise power spectrum (NPS) and task-based transfer function (TTF) were computed. Detectability index (
d
′) was computed to model a large mass in the liver, a small calcification, and a small subtle lesion with low contrast.
Results
NPS peaks were higher with AV50 than with all DLIR levels and only higher with DLIR-H than with AV100. The average NPS spatial frequencies were higher with DLIR than with IR. For all DLIR levels, TTF
50%
obtained with DLIR was higher than that with IR.
d
′ was higher with DLIR than with AV50 but lower with DLIR-L and DLIR-M than with AV100.
d
′ values were higher with DLIR-H than with AV100 for the small low-contrast lesion (10 ± 4%) and in the same range for the other simulated lesions.
Conclusions
New DLIR algorithm reduced noise and improved spatial resolution and detectability without changing the noise texture. Images obtained with DLIR seem to indicate a greater potential for dose optimization than those with hybrid IR.
Key Points
• This study assessed the impact on image quality and radiation dose of a new deep learning image reconstruction (DLIR) algorithm as compared with hybrid iterative reconstruction (IR) algorithm.
• The new DLIR algorithm reduced noise and improved spatial resolution and detectability without perceived alteration of the texture, commonly reported with IR.
• As compared with IR, DLIR seems to open further possibility of dose optimization.
In daily clinical practice, clinicians integrate available data to ascertain the diagnostic and prognostic probability of a disease or clinical outcome for their patients. For patients with suspected ...or known cardiovascular disease, several anatomical and functional imaging techniques are commonly performed to aid this endeavor, including coronary computed tomography angiography (CCTA) and nuclear cardiology imaging. Continuous improvement in positron emission tomography (PET), single-photon emission computed tomography (SPECT), and CT hardware and software has resulted in improved diagnostic performance and wide implementation of these imaging techniques in daily clinical practice. However, the human ability to interpret, quantify, and integrate these data sets is limited. The identification of novel markers and application of machine learning (ML) algorithms, including deep learning (DL) to cardiovascular imaging techniques will further improve diagnosis and prognostication for patients with cardiovascular diseases. The goal of this position paper of the European Association of Nuclear Medicine (EANM) and the European Association of Cardiovascular Imaging (EACVI) is to provide an overview of the general concepts behind modern machine learning-based artificial intelligence, highlights currently prefered methods, practices, and computational models, and proposes new strategies to support the clinical application of ML in the field of cardiovascular imaging using nuclear cardiology (hybrid) and CT techniques.
Coronary computed tomography angiography (CTA) has shown great technological improvements over the last 2 decades. High accuracy of CTA in detecting significant coronary stenosis has promoted CTA as ...a substitute for conventional invasive coronary angiography in patients with suspected coronary artery disease. In patients with coronary stenosis, CTA-derived physiological assessment is surrogate for intracoronary pressure and velocity wires, and renders possible decision-making about revascularization solely based on computed tomography. Computed tomography coronary anatomy with functionality assessment could potentially become a first line in diagnosis. Noninvasive imaging assessment of plaque burden and morphology is becoming a valuable substitute for intravascular imaging. Recently, wall shear stress and perivascular inflammation have been introduced. These assessments could support risk management for both primary and secondary cardiovascular prevention. Anatomy, functionality, and plaque composition by CTA tend to replace invasive assessment. Complete CTA assessment could provide a 1-stop-shop for diagnosis, risk management, and decision-making on treatment.
To date, sarcopenia is considered a patient-specific imaging
biomarker
able to predict clinical outcomes. Several imaging modalities, including dual-energy X-ray absorptiometry (DXA), computed ...tomography (CT), magnetic resonance (MR), and ultrasound (US), can be used to assess muscle mass and quality and to achieve the diagnosis of sarcopenia. With different extent, all these modalities can provide quantitative data, being thus reproducible and comparable over time. DXA is the one most commonly used in clinical practice, with the advantages of being accurate and widely available, and also being the only radiological tool with accepted cutoff values to diagnose sarcopenia. CT and MR are considered the reference standards, allowing the evaluation of muscle quality and fatty infiltration, but their application is so far mostly limited to research. US has been always regarded as a minor tool in sarcopenia and has never gained enough space. To date, CT is probably the easiest and most promising modality, although limited by the long time needed for muscle segmentation. Also, the absence of validated thresholds for CT measurements of myosteatosis requires that future studies should focus on this point. Radiologists have the great potential of becoming pivotal in the context of sarcopenia. We highly master imaging modalities and know perfectly how to apply them to different organs and clinical scenarios. Similarly, radiologists should master the culture of sarcopenia, and its clinical aspects and relevant implications for patient care. The medical and scientific radiological community should promote specific educational course to spread awareness among professionals.
Key Points
•
DXA is an accurate, reproducible, and widely available imaging modality to evaluate body composition, being the most commonly used radiological tool to diagnose sarcopenia in clinical practice
•
CT and MR are the gold standard imaging modalities to assess muscle mass and quality, but no clear cutoff values have been reported to identify sarcopenia, limiting the application of these modalities to research purposes
•
US has shown to be accurate in the evaluation of muscle trophism, especially in the thigh, but its current application in sarcopenia is limited
The aim of this study was to evaluate the feasibility and quality of ultra-high-resolution coronary computed tomography angiography (CCTA) with dual-source photon-counting detector CT (PCD-CT) in ...patients with a high coronary calcium load, including an analysis of the optimal reconstruction kernel and matrix size.
In this institutional review board-approved study, 20 patients (6 women; mean age, 79 ± 10 years; mean body mass index, 25.6 ± 4.3 kg/m 2 ) undergoing PCD-CCTA in the ultra-high-resolution mode were included. Ultra-high-resolution CCTA was acquired in an electrocardiography-gated dual-source spiral mode at a tube voltage of 120 kV and collimation of 120 × 0.2 mm. The field of view (FOV) and matrix sizes were adjusted to the resolution properties of the individual reconstruction kernels using a FOV of 200 × 200 mm 2 or 150 × 150 mm 2 and a matrix size of 512 × 512 pixels or 1024 × 1024 pixels, respectively. Images were reconstructed using vascular kernels of 8 sharpness levels (Bv40, Bv44, Bv56, Bv60, Bv64, Bv72, Bv80, and Bv89), using quantum iterative reconstruction (QIR) at a strength level of 4, and a slice thickness of 0.2 mm. Images with the Bv40 kernel, QIR at a strength level of 4, and a slice thickness of 0.6 mm served as the reference. Image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), vessel sharpness, and blooming artifacts were quantified. For subjective image quality, 2 blinded readers evaluated image noise and delineation of coronary artery plaques and the adjacent vessel lumen using a 5-point discrete visual scale. A phantom scan served to characterize image noise texture by calculating the noise power spectrum for every reconstruction kernel.
Maximum spatial frequency (f peak ) gradually shifted to higher values for reconstructions with the Bv40 to Bv64 kernel (0.15 to 0.56 mm -1 ), but not for reconstructions with the Bv72 to Bv89 kernel. Ultra-high-resolution CCTA was feasible in all patients (median calcium score, 479). In patients, reconstructions with the Bv40 kernel and a slice thickness of 0.6 mm showed largest blooming artifacts (55.2% ± 9.8%) and lowest vessel sharpness (477.1 ± 73.6 ΔHU/mm) while achieving highest SNR (27.4 ± 5.6) and CNR (32.9 ± 6.6) and lowest noise (17.1 ± 2.2 HU). Considering reconstructions with a slice thickness of 0.2 mm, image noise, SNR, CNR, vessel sharpness, and blooming artifacts significantly differed across kernels (all P 's < 0.001). With higher kernel sharpness, SNR and CNR continuously decreased, whereas image noise and vessel sharpness increased, with highest sharpness for the Bv89 kernel (2383.4 ± 787.1 ΔHU/mm). Blooming artifacts continuously decreased for reconstructions with the Bv40 (slice thickness, 0.2 mm; 52.8% ± 9.2%) to the Bv72 kernel (39.7% ± 9.1%). Subjective noise was perceived by both readers in agreement with the objective measurements. Considering delineation of coronary artery plaques and the adjacent vessel lumen, reconstructions with the Bv64 and Bv72 kernel (for both, median score of 5) were favored by the readers providing an excellent anatomic delineation of plaque characteristics and vessel lumen.
Ultra-high-resolution CCTA with PCD-CT is feasible and enables the visualization of calcified coronaries with an excellent image quality, high sharpness, and reduced blooming. Coronary plaque characterization and delineation of the adjacent vessel lumen are possible with an optimal quality using Bv64 kernel, a FOV of 200 × 200 mm 2 , and a matrix size of 512 × 512 pixels.
Background
Connective tissue grafting has a beneficial effect on the peri‐implant mucosa, but the effect of grafting the buccal mucosa on buccal bone thickness (BBT) has not been investigated, ...although BBT is proposed to be a key factor for the soft‐tissue contour. The aim of this trial was to assess the outcome of a connective tissue graft (CTG) in the esthetic zone of single immediate implants on the change of BBT according to cone beam computed tomography (CBCT) scan analysis.
Methods
In a 1‐year randomized controlled trial, 60 patients received an immediately placed implant and provisionalization, either combined with CTG (test group) or without CTG (control group). CBCTs were taken preoperatively (Tpre) and 1 year after definitive restoration (T2). Any change in BBT was assessed at different implant levels. Additionally, the change in mid‐buccal mucosal level (MBML) and approximal marginal bone level were assessed.
Results
Fifty‐five patients were available for statistical analysis (test group, n = 28; control group, n = 27). At T2, the average change in BBT was significantly larger in the test group (−0.84 ± 0.61 mm) than in the control group (−0.46 ± 0.54 mm, P = 0.02). A MBML gain of 0.07 ± 0.85 mm in the test and a MBML loss −0.52 ± 1.16 mm in the control group was observed at T2. Average loss of marginal bone was 0.05 ± 0.33 mm and 0.01 ± 0.38 mm, respectively.
Conclusions
The application of CTG in the esthetic zone of immediately placed and provisionalized implants is accompanied with more loss of BBT, but at the same time better maintains the mid‐buccal mucosal level.
Objective
The aim of this study was to assess the safety and efficacy of extended liver venous deprivation (eLVD), i.e. combination of right portal vein embolisation and right (accessory right) and ...middle hepatic vein embolisation before major hepatectomy for future remnant liver (FRL) functional increase.
Methods
eLVD was performed in non-cirrhotic patients referred for major hepatectomy in a context of small FRL (baseline FRL <25% of the total liver volume or FRL function <2.69%/min/m
2
). All patients underwent
99m
Tc-mebrofenin hepatobiliary scintigraphy (HBS) and computed tomographic evaluations.
Results
Ten consecutive patients underwent eLVD before surgery for liver metastases (
n
= 8), Klatskin tumour (
n
= 1) and gallbladder carcinoma (
n
= 1). FRL function increased by 64.3% (range = 28.1-107.5%) at day 21. In patients with serial measurements, maximum FRL function was at day 7 (+65.7 ± 16%). The FRL volume increased by +53.4% at 7 days (+25 ± 8 cc/day). Thirty-one days (range = 22-45 days) after eLVD, 9/10 patients were resected. No post-hepatectomy liver failure was reported. Two grade II and one grade III complications (Dindo-Clavien classification) occurred. No patient died with-in 90 days following surgery.
Conclusions
eLVD is safe and provides a marked and very rapid increase in liver function, unprecedented for an interventional radiology procedure.
Key Points
•
eLVD is safe
•
eLVD provides a marked and very rapid increase in liver function
•
After eLVD, the FRL-F increased by 64.3% (28.1-107.5%) at day 21
•
After eLVD, the maximum FRL-F was obtained at day 7 (+65.7 ± 16%)
•
After eLVD, the FRL volume increased by +53.4% at 7 days (+25 ± 8 cc/day)
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