Dual-injection Technique Research Articles

Eulerian-Lagrangian simulation and validating experiment of n-butanol/biodiesel dual-fuel impinging sprays

The dual-fuel collision phenomenon is used to realize different concentrations and reactivity stratification in the dual direct injection technique. The present work developed a dual-fuel spray collision model in the computational framework of Eulerian-Lagrangian spray simulation by introducing an additional independent variable, the fuel fraction, to the droplet probability distribution function. This model was used to investigate the macroscopic and microscopic characteristics of n-butanol/biodiesel spray collision, for which experiments were also conducted for validation. Moreover, to investigate the influence of various fuel properties (fuel density, latent heat of evaporation, and vapor pressure) on the spray characteristics, a comprehensive parametric study was conducted. Results show that the simulation result shows a good agreement with the experiment data. As the n-butanol and biodiesel sprays collide, most droplets have a higher mass ratio of biodiesel. Larger SMD is linked to droplet coalescence. Among different fuel properties, the vapor pressure and latent heat of evaporation display a significant impact on the macroscopic characteristics (collision moment and liquid-phase penetration) and microscopic characteristics (droplet number percentage variation of different fuel fractions).

A Ka-Band Low-EVM Subharmonically Injection-Locked FLL IQ Modulator Using Stacked-Boosting and Dual-Injection Technique

In this letter, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Ka$ </tex-math></inline-formula> -band low error-vector-magnitude (EVM) subharmonically injection-locked frequency-locked loop (SILFLL) in-phase and quadrature (IQ) modulator is proposed using 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS process. The proposed circuit consists of an SILFLL and four reflection-type modulators. A stacked-boosting technique is employed in the oscillation core to further extend the frequency up to 28 GHz, and a dual-injection technique is employed in the SILFLL to significantly widen the lock range. As the subharmonic number is 3, the measured phase noise at 1-MHz offset and jitter integrated from 1 kHz to 40 MHz are better than −120 dBc/Hz and 95 fs, respectively. Between 26.6 and 28.2 GHz, the proposed SILFLL IQ modulator features an EVM of within 8%, a phase error of 2°, and a magnitude error of 2% for various quadrature amplitude modulations (QAMs), and the modulation can be up to 64-QAM scheme. The work is suitable for a few advanced digital communications due to its high modulation quality.

Application of a Pickering Emulsified Polymeric Gel System as a Water Blocking Agent.

The conventional methods for controlling excess water production in oil/gas wells can be classified on the basis of the mechanism (pore-blocking mechanism and relative permeability modification) used. Gel systems developed on the basis of a pore-blocking mechanism completely block the pores and stop the flow of both oil and water, whereas a relative permeability modifier (RPM) only restricts the flow of a single phase of the fluid. The gel working on the basis of the pore-blocking mechanism is known as a total blocking gel. An invert emulsified (PAM–PEI) polymer gel is a relative permeability modifier system. The same invert emulsion system is tested as a total blocking gel system in this research work. The dual-injection technique (1st injection and 2nd injection) was used for this purpose. In this research work, the emulsion system was tested at a temperature of 105 °C. The core sections with drilled holes and fractures were used for the core flooding experiments, representing a highly fractured reservoir. The developed emulsified gel system was characterized using a dilution test, an inverted bottle test, microscopic images, and FTIR images. The emulsified polymer gel was tested using a core flooding experiment. After the 2nd injection, the postflood medical CT and micro-CT images of the core sections clearly showed the presence of two different phases in the core section, i.e., the oil phase and the gel phase. The core flooding experiment result indicates that the gel formed after the 2nd injection of the emulsion system can withstand a very high differential pressure, i.e., above 2000 psi. The gel did not allow any oil or water to be produced. Hence, the developed emulsified polymer gel system with the help of a dual-injection technique can be efficiently used as a total blocking gel for high-temperature reservoirs.

Comparison between Single- and Double-Injection Technique for Ultrasound-Guided Supraclavicular Block: A Randomized Controlled Study

Background: The supraclavicular approach to brachial plexus block is a commonly employed regional anesthesia technique for providing surgical anesthesia and postoperative analgesia for patients undergoing upper limb fractures. With ultrasound (US) guidance, the success rate of the block is increased, and complications like pneumothorax and vascular puncture are minimized. The block can be performed using single injection at the corner pocket or double injection, that is, half of the drug at the corner pocket and the remaining half at the cluster of brachial plexus divisions. Methods: After institutional ethics committee approval, we randomized 40 patients scheduled with fractures for elective upper extremity surgery under US-guided supraclavicular brachial plexus block. Twenty patients received 30 mL of local anesthetic at the corner pocket (group SI), and 20 patients received 30 mL of local anesthetic using the dual-injection technique in divided doses (group DI). Demographic data, time to block performance, time to sensory and motor block, total anesthesia-related time (TART), block success, and failure were compared between both groups. Results: The demographic data were comparable between both groups. The DI group had a significantly faster onset than the SI group (p = 0.0172). There was a statistically significant lesser performance time in group SI than in group DI (p < 0.034). The sensory and motor block achieved was comparable between both groups. Conclusion: The success rates in both the SI and DI techniques are comparable. The DI technique results in a faster onset and hence a shorter TART; however, it may not be clinically relevant.

A 17.8–34.8 GHz (64.6%) Locking Range Current-Reuse Injection-Locked Frequency Multiplier with Dual Injection Technique

A 17.8–34.8 GHz (64.6%) locking range current-reuse injection-locked frequency multiplier (CR-ILFM) with dual injection technique is presented in this paper. A dual injection technique is applied to generate differential signal and increase the power of the second-order harmonic component. The CR core is proposed to reduce the power consumption and compatibility with NMOS and PMOS injectors. The inductor-capacitor (LC) tank of the proposed CR-ILFM is designed with a fourth-order resonator using a transformer with distributed inductor to extend the locking range. The self-oscillated frequency of the proposed CR-ILFM is 23.82 GHz. The output frequency locking range is 17.8–34.8 GHz (64.6%) at a 0-dBm injection power without any additional control including supply voltage, varactor, and capacitor bank. The power consumption of the proposed CR-ILFM is 7.48 mW from a 1-V supply voltage and the die size is 0.75 mm × 0.45 mm. The CR-ILFM is implemented in a 65-nm CMOS technology.

Analgesic Effect of Dual Injection Technique for the Erector Spinae Plane Block in Beating Heart Coronary By-Pass Surgeries.

IntroductionVarious regional anesthesia techniques such as thoracic epidural, thoracic paravertebral block, erector spinae plane block (ESPB), parasternal intercostal blocks are used in cardiac surgery for postoperative analgesia. In our study, we investigated the analgesic efficacy of the dual injection technique of ESPB in beating heart coronary bypass surgeries.MethodsThe records of patients with coronary artery bypass (CABG) surgery in the beating heart at the VKV American Hospital between January and December 2019 were retrospectively analyzed. The data of 30 patients who met the criteria to be included in the study were analyzed. Whether any opioid use is required for maintenance of anesthesia it is recorded. The pain scores of the patients are recorded by the intensive care team and cardiovascular service nurses for the first 48 hours.ResultsThe absence of secondary responses to pain in all surgical periods, including skin incision and sternotomy, and low number of rating scale (NRS) scores in the postoperative 0- to 24-hour period show that the technique we developed can produce effective analgesia. After the 24th postoperative hour, the patients were followed up in the cardiovascular service and there was no opioid use between 24- to 48-hour period.ConclusionOur approach, in which the local anesthetic is applied by approaching the superior costa-transverse ligament (SCTL) in the ESPB, provides an effective analgesia in coronary artery bypass surgeries in the beating heart. The main purpose of our new approach is to increase the amount of local anesthetic in the paravertebral area. We recommend using our modified technique for effective analgesia after CABG surgeries.

Cladding-Pumped Erbium-Ytterbium Co-Doped Fiber Amplifier With Dual-Wavelength Auxiliary Signal Injection of 1030 and 1040 nm

We propose and demonstrate a cladding-pumped, erbium-ytterbium co-doped fiber amplifier (EYDFA) scheme based on dual wavelength auxiliary signal injection technique to solve the issue of the backward Yb-ASE self-lasing under strong pumping for the high-power fiber amplification of 1.5-μm kHz-linewidth linearly-polarized laser signal. With the dual wavelength auxiliary signal of 1030 and 1040 nm injection, the allowable maximum pump power without triggering the backward Yb-ASE self-lasing can be greatly increased due to the relieving effect on the inhomogeneous gain broadening. For an EYDFA with 3.8-m erbium-ytterbium co-doped double-clad fiber, the net output power is improved to 13.8 W, while the linewidth of the amplified single-transverse-mode linearly-polarized 1560 nm laser signal is still only 3.5 kHz. The SBS effect is observed to be trivial during the fiber amplification.

A Fractional-N Counter-Assisted DPLL With Parallel Sampling ILFD

A fractional-N digital phase-locked loop (DPLL) with ring oscillator based injection-locked frequency divider (ILFD) and parallel sampling phase samplers is presented. The ILFD utilizes dual path injection technique to achieve wide locking range (4.2–23 GHz) and low power consumption. A low-power parallel sampling phase sampler based time-to-digital converter (TDC), which achieves sub-gate-delay resolution by sampling the ILFD’s multi-phase outputs using parallel sampling technique, is proposed. The TDC resolution is determined by delay spacing between successive sampling clocks, which is ensured through digital calibration loops. Due to injection locking, no calibration is required to normalize the TDC step to the DCO output period. A hybrid high speed counter architecture, combining a 2 bit asynchronous counter and a 6 bit synchronous counter, is proposed to achieve high speed (>4 GHz) operation with low power consumption. The proposed design is fabricated in a 65 nm CMOS process and occupies 0.1 mm2. The synthesizer covers 13.6–16.8 GHz output and dissipates 8.5 mW. The measured output phase noise achieves −89 dBc/Hz and −125 dBc/Hz at 100 kHz and 10 MHz offsets, respectively. The measured jitter is less than 0.43 ps.

Control of combustion process in an HCCI-DI combustion engine using dual injection strategy with EGR

The objective of this study was to achieve a controlled HCCI-DI combustion using in-cylinder dual injection technique and to study the effect of premixed ratio and EGR on combustion, performance and emission characteristics of the engine. Studies were carried out up to 67% (0–67%) of the full load and a constant speed of 1500rev/min. The premixed ratio was varied from zero to a maximum of 80% of the total fuel by mass. At 50% load condition, occurrences of peak pressure, peak PRR and peak HRR varied within 5–7deg BTDC, 1.5–5deg BTDC and 1–4deg BTDC respectively. It was observed that diesel homogeneous combustion showed a two phase heat release pattern at higher premixed ratios and all combustion parameters advanced dramatically with increasing premixed ratio. The results showed that a reduction of 76% in NOX and 40% in smoke opacity were achieved using 80% premixed ratio with 30% EGR. As the premixed ratio was increased, there was an improvement in IMEP, ISFC and smoke opacity with penalties in HC and CO emissions.

Ring Oscillator Based Injection Locked Frequency Divider Using Dual Injection Paths

Ring oscillator based injection locked frequency dividers (ILFD) generally feature higher power efficiency compared to conventional static frequency dividers. However it is difficult for ring oscillator based ILFDs to achieve large division ratio and wide input locking range at the same time. To increase the input locking range, a ring oscillator based ILFD utilizing dual injection technique is proposed in this letter. For this, both tail injection and direct injection are applied in phase such that the output currents of the two mixing processes corresponding to the two injection paths are added constructively at the output frequency $\omega o$ and the overall injection efficiency is therefore increased. A differential buffer circuit with dual injection is proposed. Equivalent circuit modeling of the dual injection buffer and mathematical analysis of locking range enhancement are presented. The core ring oscillator consists of 4 stages of the dual injection buffers. It is fabricated in a 65 nm CMOS technology and consumes less than 2 mW with supply voltage of 1.2 V. Its locking range is from 1.2 to 20.7 GHz without any tuning at 0 dBm injection power level. The proposed ILFD is compact with the core only occupying 15 $\mu$ m $\,\times\,$ 30 $\mu$ m and does not need any extra controls, making it suitable for integrated wideband phase locked loop.

Lymphatic anatomy of the inguinal region in aid of vascularized lymph node flap harvesting

Vascularized lymph node transfer (VLNT) has shown promise as a treatment for breast cancer-related lymphedema, a common and debilitating condition among breast cancer survivors. In VLNT, the most popular lymph node flap donor site is the inguinal region; however, concerns about the possibility of iatrogenic lymphedema hamper the widespread adoption of VLNT. A better understanding of the anatomy of the lymphatic system in the inguinal region is essential to preserving lymph drainage in the leg and avoiding iatrogenic lymphedema. Five human cadaver hind-quarter specimens were used for this study. First, the specimens were scanned with indocyanine green fluorescence lymphography to map the lymphatic vessels. A dual injection technique using different radiocontrast media was then applied to delineate arteries and lymphatic vessels on radiographs. Finally, radiological analysis and meticulous dissection were used to investigate relationships between the arteries and lymphatic vessels. By chasing the lymphatic vessels retrogradely from their corresponding lymph nodes, we were able to divide the superficial inguinal lymph nodes into three subgroups: the abdominal, medial thigh, and lateral thigh nodes. We found no connections between the superficial and deep lymphatic system in the inguinal region. The dominant lymph nodes draining the leg were in the lower part of the inguinal triangle, and their efferent lymphatic vessels ran medial to the common femoral artery. Preserving the sentinel nodes of the lower leg in the medial thigh and their efferent lymphatic vessels is crucial to avoid iatrogenic lymphedema in limbs with donor sites for VLNT.

TCTAP C-077 PTCA of Chronic Total Occlusion: Bi-femoral Approach and Dual Injection Technique

### Patient initials or identifier number Case 1: Nazrul Case 2: Sawkot ### Relevant clinical history and physical exam C ### Procedural step 2 Cases are included in this presentation. Case 1: Mr X was diagnosed as a case of non-STEMI and old MI (Inferior) and coronary angiogram revealed -

Semi-Quantitative Parameter Analysis of DCE-MRI Revisited: Monte-Carlo Simulation, Clinical Comparisons, and Clinical Validation of Measurement Errors in Patients with Type 2 Neurofibromatosis

PurposeTo compare semi-quantitative (SQ) and pharmacokinetic (PK) parameters for analysis of dynamic contrast enhanced MR data (DCE-MRI) and investigate error-propagation in SQ parameters.MethodsClinical data was collected from five patients with type 2-neurofibromatosis (NF2) receiving anti-angiogenic therapy for rapidly growing vestibular schwannoma (VS). There were 7 VS and 5 meningiomas. Patients were scanned prior to therapy and at days 3 and 90 of treatment. Data was collected using a dual injection technique to permit direct comparison of SQ and PK parameters. Monte Carlo modeling was performed to assess potential measurement errors in SQ parameters in persistent, washout, and weakly enhancing tissues. The simulation predictions for five semi-quantitative parameters were tested using the clinical DCE-MRI data.ResultsIn VS, SQ parameters and Ktrans showed close correlation and demonstrated similar therapy induced reductions. In meningioma, only the denoised Signal Enhancement Ratio (Rse1/se2(DN)) showed a significant therapy induced reduction (p<0.05). Simulation demonstrated: 1) Precision of SQ metrics normalized to the pre-contrast-baseline values (MSErel and ∑MSErel) is improved by use of an averaged value from multiple baseline scans; 2) signal enhancement ratio Rmse1/mse2 shows considerable susceptibility to noise; 3) removal of outlier values to produce a new parameter, Rmse1/mse2(DN), improves precision and sensitivity to therapy induced changes. Direct comparison of in-vivo analysis with Monte Carlo simulation supported the simulation predicted error distributions of semi-quantitative metrics.ConclusionPK and SQ parameters showed similar sensitivity to anti-angiogenic therapy induced changes in VS. Modeling studies confirmed the benefits of averaging baseline signal from multiple images for normalized SQ metrics and demonstrated poor noise tolerance in the widely used signal enhancement ratio, which is corrected by removal of outlier values.

Ultrasound-Guided Single-Penetration Dual-Injection Block for Leg and Foot Surgery

We describe a new approach to blocking the sciatic and saphenous nerves in the proximal thigh (level of the lesser trochanter or immediately below) using a single-penetration dual-injection (SPEDI) technique. The popliteal-sciatic approach necessitates repositioning of the leg exposing the popliteal fossa and an extra injection for the saphenous nerve (SAN) block at the midthigh level. We introduce an alternative, effective, and possibly faster method. Sixty patients undergoing leg and foot surgery under general anesthesia were included. We deposited 15 mL of ropivacaine 0.75% around the sciatic nerve (SCN) and 5 mL of ropivacaine 0.75% at the SAN. Patients were randomized to the popliteal-sciatic/saphenous technique or the SPEDI technique. The primary outcome measure was performance time. Positioning time, pain assessment, nausea in the postanesthesia care unit, sufentanil demand, dermatomal anesthesia, and degree of motor blockade were also recorded. Performance time was significantly faster with the SPEDI technique (median time, 110 seconds [range, 57-315 seconds] vs 246 seconds [range, 163-472 seconds]; P < 0.0001). Positioning time was significantly shorter with the SPEDI technique (P < 0.0001). No other statistically significant differences were recorded. The SPEDI block resulted in significantly faster performance time and reduced positioning time with statistically equal efficacy in relation to pain assessment, nausea, sufentanil demand, dermatomal anesthesia, and motor blockade. The SPEDI block is statistically an equally effective alternative to the traditional popliteal-sciatic/saphenous block combination for leg and foot surgery, but it is faster, requires only 1 skin penetration, and does not require repositioning of the leg.

In Response

Our data clearly show that there is communication between the paravertebral and epidural spaces, with contrast spread into the epidural space in 40% of cadavers. Epidural and intercostal spread of contrast likely contribute significantly to analgesic efficacy from paravertebral blockade, and this is stated in our conclusion.1 We make no assertions that paravertebral blockade is the preferred method of pain relief, nor do we assert that it is “superior or safer” after thoracic surgery. We state that the paravertebral space can be easily identified with ultrasound on all cadavers and that an in-plane needle approach using ultrasound is feasible and reliable. We provide an anatomical basis for the efficacy of paravertebral blockade and state clearly that spread of contrast in cadavers is highly variable. We conclude that a dual injection technique at 2 different levels covers more thoracic dermatomes than does a single injection technique, because of intercostal spread, but given that ours is a cadaveric study, we make no comment on the quality of analgesia nor complications such as hypotension or nausea. We emphasize in our conclusion that these findings need to be confirmed in a patient population before definite recommendations are made. We found no evidence of spread to the subarachnoid space.1 Finally, we agree with Norum and Braevik that the paravertebral space is indeed in close proximity to pleura and the spinal cord2 and also agree that the indications, contraindications, and complications of paravertebral block can be similar to those of a thoracic epidural and that postoperative patients should be monitored in a similar manner. Brian Cowie, MB, BS, FANZCA Desmond McGlade, MBBS, FANZCA Michael J. Barrington, MBBS, FANZCA Department of Anaesthesia St. Vincent's Hospital Melbourne, Australia [email protected] Jason Ivanusic, PhD Department of Anatomy and Cell Biology University of Melbourne Melbourne, Australia

Ultrasound-Guided Thoracic Paravertebral Blockade

Multiple approaches to the paravertebral space have been described to produce analgesia after thoracic surgery. Ultrasound-guided regional anesthesia has the potential to improve efficacy and reduce complications via real-time visualization of the paravertebral space, surrounding structures, and the approaching needle. We compared a single- versus dual-injection technique for ultrasound-guided paravertebral blockade in a cadaver model, evaluating the spread of contrast dye and location of a catheter. Thirty paravertebral injections and 20 catheter placements were performed on 10 fresh cadavers. The paravertebral space was identified using an ultrasound probe in the transverse plane using a linear transducer. An in-plane needle approach was used. Using analine contrast dye, a single 20-mL injection at T6-7 on one side and a dual-injection technique of 10 mL at T3-4 and T7-8 on the contralateral side were performed on each cadaver, followed by insertion of a catheter through the needle. The cadaver was then dissected to evaluate spread of contrast dye and catheter location. The paravertebral space was easily identified with ultrasound on each cadaver. Contrast dye was seen to surround somatic and sympathetic nerves in the paravertebral, intercostal, and epidural spaces. Contrast dye was present in 19 of 20 paravertebral spaces over 3 to 4 segments (range, 0-10) with no significant differences between single- and dual-injection techniques. Contrast dye spread more extensively across intercostal segments with 4.5 spaces (range, 2-10) covered with a single injection and 6 spaces (range, 2-8) covered with a dual-injection technique (P = 0.03). There was epidural spread of contrast in 40% of paravertebral injections in both single- and dual-injection techniques. Catheters were located in the paravertebral space (60%), prevertebral space (20%), and epidural space (5%). Transverse in-plane ultrasound-guided needle insertion into the thoracic paravertebral space is both feasible and reliable. However, paravertebral spread of contrast is highly variable with intercostal and epidural spread likely contributing significantly to the analgesic efficacy. A dual-injection technique at separate levels seems to cover more thoracic dermatomes because of greater segmental intercostal spread (rather than paravertebral spread) than a single-injection approach. Catheters are located in nonideal positions in 40% of cases using this in-plane technique.

Low-power wide-locking-range injection-locked frequency divider for OFDM UWB systems

This paper describes a divide-by-two injection-locked frequency divider (ILFD) for frequency synthesizers as used in multiband orthogonal frequency division multiplexing (OFDM) ultra-wideband (UWB) systems. By means of dual-injection technique and other conventional tuning techniques, such as DCCA and varactor tuning, the divider demonstrates a wide locking range while consuming much less power. The chip was fabricated in the Jazz 0.18 μm RF CMOS process. The measurement results show that the divider achieves a locking range of 4.85 GHz (6.23 to 11.08 GHz) at an input power of 8 dBm. The core circuit without the test buffer consumes only 3.7 mA from a 1.8 V power supply and has a die area of 0.38 × 0.28 mm2. The wide locking range combined with low power consumption makes the ILFD suitable for its application in UWB systems.

Lymphatic mapping with 99mTc-Evans Blue dye in sheep

99mTc-Evans Blue (EB) is an agent that contains both radioactive and color signals in a single dose. Earlier studies in animal models have suggested that this agent when compared with the dual-injection technique of radiocolloid/blue dye can successfully discriminate the sentinel lymph node. The aim of this study was to investigate the potential of 99mTc-EB as an agent to map the lymphatic system in an ovine model. Doses of 99mTc-EB (23 MBq) containing EB dye (4 mg) were administered intradermally to the limbs of four anesthetized sheep, and they were then imaged over 20-30 min using a gamma camera. The study protocol was repeated using 99mTc-antimony trisulfide colloid (ATC) and Patent Blue V dye. The lymph nodes (popliteal, inguinal, and iliac for hind limbs or prescapular for fore limbs) were identified with a gamma probe during the operative exposure, then dissected and counted in a large volume counter. Simple and complex (dual) drainage patterns were visible on the scans, and the sentinel node was more radioactive than higher tier nodes in a chain, for both radiotracers. For 99mTc-EB, maximum radioactive uptake was achieved at 3-6 min for popliteal lymph nodes, 12-14 min for iliac nodes, and 13-14 min for prescapular nodes. 99mTc-ATC resulted in maximum radioactive uptake at 4-6 min for popliteal lymph nodes, 13 min for an inguinal node, 13-20 min for iliac nodes, and 18 min for a prescapular node. Following 99mTc-EB injection, 15/15 lymph nodes harvested were all radioactive and blue. For 99mTc-radiocolloid/Patent Blue V injection, 8/14 nodes were radioactive and blue, and 6/14 nodes were radioactive only. The soluble radiotracer 99mTc-EB appeared to be a useful lymphoscintigraphic agent in sheep, in which radioactive counts from superficial lymphatic channels and lymph nodes were sufficient for planar imaging. In comparison with 99mTc-antimony trisulfide colloid, both tracers discriminated the sentinel lymph node up to 50 min after administration; however, 99mTc-EB had the advantage of providing radioactive (gamma probe) and color signals simultaneously during the operative exposure.

A dual contrast injection technique for multidetector computed tomography angiography of Fontan procedures

Extracardiac and lateral tunnel Fontan palliations result in caval venous return to the branch pulmonary arteries without prior blood mixing in the right atrium. Single contrast injection techniques result in suboptimal pulmonary computed tomography angiography since blood streaming results in asymmetric pulmonary flow of injected contrast. We used a dual injection technique--dorsal foot vein and upper extremity vein to achieve optimal simultaneous opacification of the inferior and superior venae cavae and branch pulmonary arteries. The resulting dataset allowed for excellent 3D volume renderings and multiplanar reformat images useful for stenosis, aneurysm, and metal stent evaluation.

Cephalic vascular anatomy in flamingos (Phoenicopterus ruber) based on novel vascular injection and computed tomographic imaging analyses

Head vascular anatomy of the greater (or Caribbean) flamingo (Phoenicopterus ruber) is investigated and illustrated through the use of a differential contrast, dual vascular injection technique, and high-resolution X-ray computed tomography (CT), allowing arteries and veins to be differentiated radiographically. Vessels were digitally isolated with segmentation tools and reconstructed in 3D to facilitate topographical visualization of the cephalic vascular tree. Major vessels of the temporal, orbital, pharyngeal, and encephalic regions are described and illustrated, which confirm that the general pattern of avian cephalic vasculature is evolutionarily conservative. In addition to numerous arteriovenous vascular devices, a previously undescribed, large, bilateral, paralingual cavernous sinus that excavates a large bony fossa on the medial surface of the mandible was identified. Despite the otherwise conservative vascular pattern, this paralingual sinus was found only in species of flamingo and is not known otherwise in birds. The paralingual sinus remains functionally enigmatic, but a mechanical role in association with the peculiar lingual-pumping mode of feeding in flamingos is perhaps the most likely hypothesis.