Nonlinear beamforming for intracardiac echocardiography: a comparative study.

Intracardiac echocardiography (ICE) enables cardiac imaging with a wide field of view, deep imaging depth, and high frame rate during surgery. However, strong sidelobe and grating lobe artifacts created by the ultra-compact transducer degrade its image quality, making diagnosis and monitoring of treatment difficult. Conventionally, aperture apodization algorithms are often used to suppress sidelobe and grating lobe artifacts at the expense of lateral resolution, which is undesirable in ICE. In this study, we present comparative results of the beamforming methods specifically in ICE application. We demonstrate and compare five nonlinear beamforming algorithms in ICE: nonlinear pth root delay and sum (NL-p-DAS), nonlinear pth root spectral magnitude scaling (NL-p-SMS), delay-and-sum with coherence factors (DAS + SCF), delay and sum with apodization (DAS + apodization) and delay and sum (DAS). Phantom and ex-vivo experiment compare the performance of each algorithm in static and dynamic conditions. DAS + SCF shows the best lateral resolution, and all four algorithms improve the image contrast and sidelobe suppression over conventional DAS. NL-p-SMS stands out for the best axial resolution and suppression of grating lobe artifacts. For motion tracking, NL-p-SMS shows better temporal resolution than other methods. Overall, all the beamforming algorithms other than DAS showed improved image quality. Among them, NL-p-SMS, which has a high temporal resolution, showed the potential for providing more accurate information regards movement tracking. Supplementary Information: The online version contains supplementary material available at 10.1007/s13534-024-00352-9.

Detection of micro inclusions in steel sheets using high-frequency ultrasound speckle analysis.

With the increasing need for steel sheet quality assurance, the detection of micro-scaled inclusions in steel sheets has become critical. Many techniques have been explored to detect inclusions, e.g., visual inspection, radiography, magnetic testing, and ultrasound. Among these methods, ultrasound (US) is the most commonly used non-destructive testing (NDT) method due to its ease of use and deep penetration depth. However, ultrasound currently cannot be used for detecting the micro-scaled inclusions due to low spatial resolution, e.g., less than 30 µm, which are the key important factors causing the cracks in the high-quality steel sheets. Here, we demonstrate a high-resolution US imaging (USI) using high-frequency US transducers to image micro inclusions in steel sheets. Our system utilizes through-transmission USI and identifies ultrasound scattering produced by the inclusions. We first ultrasonically imaged the artificial flaws induced by the laser on the steel sheet surface for validating the system. We then imaged the real inclusions in the steel sheets formed during manufacturing processes and analyzed them to derive quantitative parameters related to the number of micro-scaled inclusions. Our results confirm that inclusions less than 30 µm can be identified using our high-resolution USI modality and has the potential to be used as an effective tool for quality assurance of the steel sheets.

Real-time delay-multiply-and-sum beamforming with coherence factor for in vivo clinical photoacoustic imaging of humans.

In the clinical photoacoustic (PA) imaging, ultrasound (US) array transducers are typically used to provide B-mode images in real-time. To form a B-mode image, delay-and-sum (DAS) beamforming algorithm is the most commonly used algorithm because of its ease of implementation. However, this algorithm suffers from low image resolution and low contrast drawbacks. To address this issue, delay-multiply-and-sum (DMAS) beamforming algorithm has been developed to provide enhanced image quality with higher contrast, and narrower main lobe compared but has limitations on the imaging speed for clinical applications. In this paper, we present an enhanced real-time DMAS algorithm with modified coherence factor (CF) for clinical PA imaging of humans in vivo. Our algorithm improves the lateral resolution and signal-to-noise ratio (SNR) of original DMAS beamformer by suppressing the background noise and side lobes using the coherence of received signals. We optimized the computations of the proposed DMAS with CF (DMAS-CF) to achieve real-time frame rate imaging on a graphics processing unit (GPU). To evaluate the proposed algorithm, we implemented DAS and DMAS with/without CF on a clinical US/PA imaging system and quantitatively assessed their processing speed and image quality. The processing time to reconstruct one B-mode image using DAS, DAS with CF (DAS-CF), DMAS, and DMAS-CF algorithms was 7.5, 7.6, 11.1, and 11.3 ms, respectively, all achieving the real-time imaging frame rate. In terms of the image quality, the proposed DMAS-CF algorithm improved the lateral resolution and SNR by 55.4% and 93.6 dB, respectively, compared to the DAS algorithm in the phantom imaging experiments. We believe the proposed DMAS-CF algorithm and its real-time implementation contributes significantly to the improvement of imaging quality of clinical US/PA imaging system.

Real-Time Photoacoustic Thermometry Combined With Clinical Ultrasound Imaging and High-Intensity Focused Ultrasound.

High-intensity focused ultrasound (HIFU) treatment is a promising non-invasive method for killing or destroying the diseased tissues by locally delivering thermal and mechanical energy without damaging surrounding normal tissues. In HIFU, measuring the temperature at the site of delivery is important for improving therapeutic efficacy, controlling safety, and appropriately planning a treatment. Several researchers have proposed photoacoustic thermometry for monitoring HIFU treatment, but they had many limitations, including the inability to image while the HIFU is on, inability to provide two-dimensional monitoring, and the inability to be used clinically. In this paper, we propose a novel integrated real-time photoacoustic thermometry system for HIFU treatment monitoring. The system provides ultrasound B-mode imaging, photoacoustic structural imaging, and photoacoustic thermometry during HIFU treatment in real-time for both in vitro and in vivo environments, without any interference from the strong therapeutic HIFU waves. We have successfully tested the real-time photoacoustic thermometry by investigating the relationship between the photoacoustic amplitude and the measured temperature with in vitro phantoms and in vivo tumor-bearing mice. The results show the feasibility of a real-time photoacoustic thermometry system for safe and effective monitoring of HIFU treatment.

Successful treatment of type I endoleak of common iliac artery with balloon expandable stent (Palmaz XL stent) during endovascular aneurysm repair.

Type 1 endoleak of common iliac artery (type I(b) endoleak) should be treated during endovascular aneurysm repair (EVAR). An 86-year-old female was diagnosed with abdominal aortic aneurysm measuring 6.6 cm in diameter and right internal iliac artery aneurysm measuring 4.0 cm in diameter. She underwent EVAR after right internal iliac artery embolization. There was type I(b) endoleak, which was repaired by balloon-expandable stent, Palmaz XL stent (Cordis). We report successful treatment of type I(b) endoleak with Palmaz XL stent, which may be considered as an alternative option for type I(b) endoleak after EVAR.

Combination treatment with intrahepatic arterial infusion and intratumoral injection chemotherapy in patients with far-advanced hepatocellular carcinoma and arterioportal or arteriovenous shunts: preliminary results.

BACKGROUND/AIMS: Combination treatment consisting of hepatic arterial infusion chemotherapy with epirubicin and cisplatin (HAIC-EC) and systemic infusion of low-dose 5-fluorouracil (5-FU) are sometimes effective against advanced hepatocellular carcinoma (HCC). However, there is no effective treatment for advanced HCCs with arterioportal shunts (APS) or arteriovenous shunts (AVS). METHODS: We investigated a response and adverse events of a new combination protocol of repeated HAIC-EC and percutaneous intratumoral injection chemotherapy with a mixture of recombinant interferon-gamma (IFN-γ) and 5-FU (PIC-IF) in patients with far-advanced HCCs with large APSs or AVSs. RESULTS: There was a complete response (CR) for the large vascular shunts in all three patients and for all tumor burdens in two patients. Significant side effects were flu-like symptoms (grade 2) and bone marrow suppression (grade 2 or 3) after each cycle, but these were well-tolerated. CONCLUSIONS: These results suggest that the combination of HAIC-EC and PIC-IF is a new and promising approach for advanced HCC accompanied by a large APS or AVS.

[A case of acute phlegmonous gastritis causing gastroparesis and cured with medical treatment alone].

Acute phlegmonous gastritis is an uncommon disease, often fatal condition characterized by suppurative bacterial infection of the gastric wall. It has a high mortality rate mainly because the diagnosis is usually made late. Until recently, gastrectomy in combination with antibiotics was recommended. We had experienced a case of 66-year-old man presented with epigastric pain, nausea, vomiting, and hematemesis, followed by aspiration pneumonia. At upper gastrointestinal endoscopy, the gastric lumen was narrow, and the mucosa was severely inflamed, which was erythematous, swelled, and showed necrotic areas covered with purulent exudate. Klebsiella oxytoca and Acinetobacter lwoffii were isolated in the gastric tissue culture. Contrast-enhanced computerized tomography scan of abdomen demonstrated diffuse gastric wall thickening and an intramural abscess in the gastric antral wall. Although delayed gastric emptying by gastroparesis prolonged the in-hospital period, the only medical treatment with antibiotics alone successfully cured the patient without gastrectomy.

Antibiotic resistance profiles of Staphylococcus pseudintermedius isolates from canine patients in Korea.

In this study, the prevalence of antibiotic resistance was examined among 74 Staphylococcus pseudintermedius strains recently isolated from clinical cases of canine pyoderma and otitis externa at the veterinary teaching hospital at Konkuk University, Korea. Bacterial resistance to the nine commonly used antibiotics was evaluated by a standard disk diffusion technique based on the guidelines of the Clinical and Laboratory Standards Institute. The results demonstrated that most S. pseudintermedius isolates were resistant to penicillin (95.9%) or tetracycline (91.9%), but highly susceptible to amoxicillin/clavulanic acid (90.5%). Among the 74 isolates, 13 mecA-positive and methicillin-resistant S. pseudintermedius (MRSP) strains were identified, displaying a high level of resistance (84.6- 100%) to each of the individual antibiotics evaluated, with the exception of amoxicillin/clavulanic acid (46.2% resistance). Notably, all of the MRSP isolates exhibited simultaneous resistance to four or more different antibiotics, indicating that they are multiple drug resistant (MDR) strains. Taken together, these results imply that more careful selection or prescription of antibiotics for canine pyoderma and otitis externa should be required for reducing the emergence and/or spread of MDR strains, especially MDR-MRSP isolates, in veterinary pet clinics in Korea.

Auto-excision of selectable marker genes from transgenic tobacco via a stress inducible FLP/FRT site-specific recombination system.

Antibiotic resistance marker genes are powerful selection tools for use in plant transformation processes. However, once transformation is accomplished, the presence of these resistance genes is no longer necessary and can even be undesirable. We herein describe the successful excision of antibiotic resistance genes from transgenic plants via the use of an oxidative stress-inducible FLP gene. FLP encodes a recombinase that can eliminate FLP and hpt selection genes flanked by two FRT sites. During a transformation procedure in tobacco, transformants were obtained by selection on hygromycin media. Regenerants of the initial transformants were screened for selective marker excision in hydrogen peroxide supplemented media and both the FLP and hpt genes were found to have been eliminated. About 13-41% of regenerated shoots on hydrogen peroxide media were marker-free. This auto-excision system, mediated by the oxidative stress-inducible FLP/FRT system to eliminate a selectable marker gene can be very readily adopted and used to efficiently generate marker-free transgenic plants.

The comparison of VATS ramicotomy and VATS sympathicotomy for treating essential hyperhidrosis.

This study was undertaken to determine if better results could be achieved by comparing the results of a thoracic sympathetic ramicotomy (division of rami communicantes) with a conventional thoracic sympathicotomy (division of sympathetic trunk) for treating essential hyperhidrosis. From August 2001 to February 2002, 29 consecutive patients underwent surgery of the sympathetic nerves in order to treat severe essential hyperhidrosis. Of these patients, a ramicotomy was performed under VATS (VATS-R) in 13 patients, sympathicotomy under VATS (VATS-S) in 13, a unilateral ramicotomy and contralateral sympathicotomy under VATS (VATS-RS) in 2 and a sympathicotomy via a thoracotomy (T-S) in 1. There was no significant difference between the VATS ramicotomy group (VATS-R, n=13) and VATS sympathicotomy group (VATS-S, n=13) in terms of gender, pleural adhesions or comorbidities. However, the age of the VATS-S group at surgery was higher than that of the VATS-R group (p=0.050). The operation times, and hospital stays of the groups were 51.5 and 41.9 minutes, and 2.0 and 2.3 days, respectively. The recurrence rate of the operated sites according to the surgical methods (ramicotomy and sympathicotomy regardless of VATS) was 21.4% (6/28) in the ramicotomy group and 6.7% (2/30) in the sympathicotomy group, but there was no statistical significance (p=0.101). This study compared the dryness of the enervated sites and the severity of compensatory sweating among the ramicotomy (n=11, excluded 2 re-operated cases from 13 VATS-R), sympathicotomy (n=14, VATS-S 13 and T-S 1) and the synchronous or metachronous ramicotomy/sympathicotomy groups (n=4, included 2 reoperated cases of VATS-R). The sympathicotomy group had an over-dryness of the enervated sites (dryness 1.4, from 1 to 3; 1:over-dried, 2:humid, 3:persistent sweating) and complained of severe compensatory sweating (severity 3.5, from 1 to 4; 1:absent, 2:mild, 3:embarrassing, 4:disabling). However, the patients whounderwent a ramicotomy maintained some humidity of the enervated sites (dryness 2.0, p=0.012) and showed milder compensatory sweating (severity 2.7, p=0.056) than those in the sympathicotomy group. Furthermore, the dryness of the ramicotomy side was different from that of the sympathicotomy side in 3 out of 4 ramicotomy / sympathicotomy (R+S) patients (the side of the ramicotomy was humid and that of the sympathicotomy was over-dried). The average dryness and the compensatory sweating at these sites were in the midst of the two groups (dryness and severity 1.6 and 3.0, respectively). A ramicotomy can prevent over-dryness of the enervated area and decrease the severity of compensatory sweating through the selective division of the rami communicantes of the thoracic sympathetic ganglia. Postoperatively, almost all ramicotomy patients had no functional problems in daily life or in their occupational activity, because they could maintain hand humidity. Moreover, they showed no more than a mild degree of compensatory sweating and reported high long-term satisfaction rates. Therefore, a sympathetic ramicotomy rather than a conventional sympathicotomy is recommended as a more selective and physiologic modality for treating essential hyperhidrosis.