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Sim-to-Real: Employing ultrasonic guided wave digital surrogates and transfer learning for damage visualization

Alguri KS, Chia CC, Harley JB

Ultrasonics, 2021 Mar;111:106338.
PMID: 33338729 DOI: 10.1016/j.ultras.2020.106338

Wavefield imaging is a powerful visualization tool in nondestructive evaluation for studying ultrasonic wave propagation and its interactions with damage. To isolate and study damage scattering, damage-free baseline data is often subtracted from a wavefield. This is often necessary because the damage wavefield can be orders of magnitude weaker than the incident waves. Yet, baselines are not always accessible. When the baselines are accessible, the experimental conditions for the baseline and test data must be extremely similar. Researchers have created several baseline-free approaches for isolating damage wavefields, but these often rely on specific experimental setups. In this paper, we discuss a flexible approach based on ultrasonic guided wave digital surrogates (i.e., numerical simulations of incident waves) and transfer learning. We demonstrate this approach with two setups. We first isolate reflections from a circular, 2 mm diameter half-thickness hole on a 10 × 10 cm steel plate. We then isolate 8 circular, half-thickness holes of various diameters from 1 mm to 40 mm on a 60 × 60 cm steel plate. The second plate has a non-square geometry and the data has multi-path reflections. With both data sets, we isolate damage reflections without explicit experimental baselines. We also briefly illustrate the comparison of our dictionary learning method with wavenumber filtering technique which is often used to enhance the defect wavefields.

Matched MeSH terms: Diagnostic Imaging
Image analysis procedure for the optical scanning of fine-root dynamics: errors depending on the observer and root-viewing window size

Kume T, Ohashi M, Makita N, Kho LK, Katayama A, Endo I, et al.

Tree Physiol, 2018 12 01;38(12):1927-1938.
PMID: 30452737 DOI: 10.1093/treephys/tpy124

Clarifying the dynamics of fine roots is critical to understanding carbon and nutrient cycling in forest ecosystems. An optical scanner can potentially be used in studying fine-root dynamics in forest ecosystems. The present study examined image analysis procedures suitable for an optical scanner having a large (210 mm × 297 mm) root-viewing window. We proposed a protocol for analyzing whole soil images obtained by an optical scanner that cover depths of 0-210 mm. We tested our protocol using six observers with different experience in studying roots. The observers obtained data from the manual digitization of sequential soil images recorded for a Bornean tropical forest according to the protocol. Additionally, the study examined the potential tradeoff between the soil image size and accuracy of estimates of fine-root dynamics in a simple exercise. The six observers learned the protocol and obtained similar temporal patterns of fine-root growth and biomass with error of 10-20% regardless of their experience. However, there were large errors in decomposition owing to the low visibility of decomposed fine roots. The simple exercise revealed that a smaller root-viewing window (smaller than 60% of the original window) produces patterns of fine-root dynamics that are different from those for the original window size. The study showed the high applicability of our image analysis approach for whole soil images taken by optical scanners in estimating the fine-root dynamics of forest ecosystems.

Matched MeSH terms: Diagnostic Imaging/methods
Fulltext Mechanisms of cervical spine injuries for non-fatal motorcycle road crash

Ooi SS, Wong SV, Radin Umar RS, Azhar AA, Yeap JS, Megat Ahmad MMH

Med J Malaysia, 2004 Jun;59(2):146-52.
PMID: 15559162 MyJurnal

Cervical spine injuries such as subluxation and fracture dislocation have long been known to result in severe consequences, as well as the trauma management itself. The injury to the region has been identified as one of the major causes of death in Malaysian motorcyclists involved in road crashes, besides head and chest injuries (Pang, 1999). Despite this, cervical spine injury in motorcyclists is not a well-studied injury, unlike the whiplash injury in motorcar accidents. The present study is a retrospective study on the mechanisms of injury in cervical spine sustained by Malaysian motorcyclists, who were involved in road crash using an established mechanistic classification system. This will serve as an initial step to look at the cervical injuries pattern. The information obtained gives engineer ideas to facilitate design and safety features to reduce injuries. All cervical spine injured motorcyclists admitted to Hospital Kuala Lumpur between January 1, 2000 and December 31, 2001 were included in the present study. Based on the medical notes and radiological investigations (X-rays, CT and MRI scans), the mechanisms of injuries were formulated using the injury mechanics classification. The result shows that flexion of the cervical vertebrae is the most common vertebral kinematics in causing injury to motorcyclists. This indicates that the cervical vertebrae sustained a high-energy loading at flexion movement in road crash, and exceeded its tolerance level. The high frequency of injury at the C5 vertebra, C6 vertebra and C5-C6 intervertebral space are recorded. Classification based on the Abbreviated Injury Scale (AIS) is made to give a view on injury severity, 9.1% of the study samples have been classified as AIS code 1, 51.5% with AIS 2 and 21.2% with AIS 3.

Matched MeSH terms: Diagnostic Imaging
A case of atypical imaging of Nasopharyngeal Carcinoma in an adolescent: A diagnostic challenge

Teo SW, Noorafidah MD, Laili SAL

Med J Malaysia, 2020 03;75(2):175-177.
PMID: 32281604

Nasopharyngeal mass in paediatric population is usually benign and malignant nasopharyngeal tumours such as carcinoma is rare. We report a case of nasopharyngeal carcinoma (NPC) in an adolescent with atypical imaging findings that mimicked a benign mass. This highlights the importance of a comprehensive review on the distinctive radiographic features of paediatric nasopharyngeal mass. We discuss the imaging features of NPC in the paediatric group, which differ from the elderly patients. By recognising these distinctive imaging features, it may help in diagnosing typical case. This case report serves as a reminder that NPC, despite being uncommon, should be considered in the differential diagnosis of a juvenile nasopharyngeal mass.

Matched MeSH terms: Diagnostic Imaging
Diagnostic accuracy of pneumonia in Hospital Tuanku Ja'afar Seremban, a tertiary hospital

Poh KW, Cheok LH, Liow JH, Mat Soom MA, Azlina S, Nadiah MN, et al.

Med J Malaysia, 2020 01;75(1):7-11.
PMID: 32008012

OBJECTIVES: The primary objective of this study was to describe the accuracy of pneumonia diagnosis, both community-acquired pneumonia (CAP) and hospitalacquired pneumonia (HAP). Secondary objectives were describing the choice of antibiotics used, pathogens isolated, and predictive parameters in diagnosing pneumonia.
METHODS: This was a prospective cross-sectional study to determine the accuracy of the diagnosis of CAP and HAP admitted to Hospital Tuanku Ja'afar. All patients aged ≥12 years admitted to the general medical ward with the diagnosis of CAP or HAP were included in the study. Chest radiograph interpretation was done by certified radiologists. An accurate diagnosis of pneumonia was defined by clinical signs and symptoms of pneumonia supported by radiographical evidence.
RESULTS: A total of 159 patients were enrolled into the study from January 2018 to February 2018. Of these only 59(37.1%) cases were accurately diagnosed as pneumonia. Amongst those with pneumonia diagnosis made by the emergency department, medical officers and specialists of medical department; 65.4%, 60% and 47.3% respectively were not pneumonia. Amoxicillin with clavulanate and azithromycin were amongst the most common first choice of antibiotic used (46.5%). In this study, pathogens were isolated either by blood culture or sputum culture in only 20 (12.6%) patients. There was no significant predictive parameter identified in this study, which included white cell counts, Creactive protein (CRP) levels, erythrocyte sedimentation rate (ESR), and Pao2/FiO2 ratio.
CONCLUSION: About two-thirds of patients diagnosed with pneumonia did not have a compatible radiological finding. Better tools and systems are needed to aid in the diagnosis of pneumonia.

Matched MeSH terms: Diagnostic Imaging
Community-acquired necrotising pneumonia caused by Panton-Valentine leucocidin-producing methicillin-resistant Staphylococcus aureus

Leong CL, Norazah A, Azureen A, Lingam R

Med J Malaysia, 2017 12;72(6):378-379.
PMID: 29308781

A 61-year-old male presented with community-onset pneumonia not responding to treatment despite given appropriate antibiotics. Computed tomography scan of the thorax showed large multiloculated pleural effusion with multiple cavitating foci within collapsed segments; lesions which were suggestive of necrotising pneumonia. Drainage of the effusion and culture revealed methicillin-resistant Staphylococcus aureus, which had the same antibiotic profile with the blood isolate and PVL gene positive.

Matched MeSH terms: Pneumonia, Necrotizing/diagnostic imaging
Necrotising pneumonia: A pneumonia that may need surgical intervention

Ooi SY, Lee SW

Med J Malaysia, 2017 12;72(6):367-369.
PMID: 29308776 MyJurnal

Pneumonia is primarily a disease that is usually managed medically with antibiotics. However, in rare cases it may progress to necrotising pneumonia, which is an uncommon but severe complication of bacterial pneumonia. This case illustrates a typical case of necrotising pneumonia complicated with parenchymal and pleural complication such as empyema, pneumothorax with possible bronchopleural fistula. Early consultation with thoracic surgeon can be life-saving.

Matched MeSH terms: Pneumonia, Necrotizing/diagnostic imaging
Pre-operative ultrasonographic prediction of hamstring autograft size for anterior cruciate ligament reconstruction surgery

Mohd Asihin MA, Bajuri MY, Ahmad J, Syed Kamaruddin SF

Ceylon Med J, 2018 03 31;63(1):11-16.
PMID: 29754479

Objectives: To evaluate the feasibility of ultrasonographic examination in predicting 4-strand semitendinosus and gracilis tendon (4S-STG) autograft size preoperatively in anterior cruciate ligament reconstruction and to evaluate the use of anthropometric measurement to predict the 4-strand semitendinosus and gracilis tendons (4S-STG) autograft size pre-operatively in anterior cruciate ligament reconstruction.
Method: Twenty-seven patients were included in this study conducted from 1st January to 31st December 2013. All patients were skeletally mature and scheduled to undergo primary anterior cruciate ligament reconstruction using 4S-STG autograft. Ultrasonographic examination of semitendinosus and gracilis tendons to measure the cross sectional area was conducted and anthropometric data (weight, height, leg length and thigh circumference) was measured one day prior to surgery. True autograft diameters were measured intraoperatively using closed-hole sizing block in 0.5 mm incremental size.
Results: There is a statistically significant correlation between the measured combined cross sectional area (semitendinosus and gracilis tendons) and 4S-STG autograft diameter (p = 0.023). An adequate autograft size (at least 7 mm) can be obtained when the combined cross sectional area is at least 15 mm2. There was no correlation with the anthropometric data except for thigh circumference (p = 0.037). Autograft size of at least 7 mm can be obtained when the thigh circumference is at least 41 mm.
Conclusions: Both combined cross sectional area (semitendinosus and gracilis tendons) and thigh circumference can be used to predict an adequate 4S-STG autograft size.

Matched MeSH terms: Hamstring Tendons/diagnostic imaging*
Roux-en-Y gastric bypass for lower esophageal submucosal cancer in an obese diabetic patient

Almulaifi AM, Lee WJ, Hong PE

Surg Obes Relat Dis, 2014 Nov-Dec;10(6):e73-5.
PMID: 25002323 DOI: 10.1016/j.soard.2014.04.013
Matched MeSH terms: Diagnostic Imaging
Fulltext Painful Pes Anserine Bursitis Following Total Knee Replacement Surgery: Two cases

Ariff MAM, Ros MIAC, Yahaya NHM

Sultan Qaboos Univ Med J, 2018 Feb;18(1):e97-e99.
PMID: 29666689 DOI: 10.18295/squmj.2018.18.01.016

Pes anserine bursitis (PAB) is an inflammation of the bursa located between the medial aspect of the tibia and the hamstring muscles. It is common in patients with degenerative or inflammatory knee arthritis, usually has a self-limiting course and tends to respond well to conservative treatment. However, painful PAB directly following total knee replacement surgery is rare. We report two such cases who were diagnosed via ultrasonography at the Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia, in 2015. Both patients were treated locally with triamcinolone acetonide under ultrasound guidance and responded well to treatment.

Matched MeSH terms: Hamstring Muscles/diagnostic imaging
Fulltext Preparing effective illustrations. Part 2: photographs, images and diagrams

Ng KH, Peh WC

Singapore Med J, 2009 Apr;50(4):330-4; quiz 335.
PMID: 19421674

In part two of "Preparing effective illustrations", the other three categories, viz. photographs, radiological images and diagrams, are discussed. Illustrations provide visual information to supplement the results in a scientific paper, and create a visual impact that can improve the readability of a paper. This article provides some basic guidelines to assist authors in preparing effective photographs, radiological images and diagrams.

Matched MeSH terms: Diagnostic Imaging*
Fulltext Computed tomography of blunt renal trauma

Razali MR, Azian AA, Amran AR, Azlin S

Singapore Med J, 2010 Jun;51(6):468-73; quiz 474.
PMID: 20658105

Renal injury is observed in 10 percent of cases of abdominal trauma, and the majority (80 percent to 90 percent) of these are attributable to blunt trauma. Intravenous urography and ultrasonography of the abdomen were previously the modalities of choice in the imaging of renal injuries. However, computed tomography (CT) is currently the imaging modality of choice in the evaluation of blunt renal injury, since it provides the exact staging of renal injuries. The purpose of this article is to describe the CT staging of renal injuries observed in blunt abdominal trauma based on the Federle Classification and the American Association for the Surgery of Trauma renal injury severity scale.

Matched MeSH terms: Diagnostic Imaging/methods
Fulltext 18F-FDG positron emission tomography/computed tomography and the "underground map" appearance in imaging Horton's arteritis

Abdul Jalil N, Abdul Rahim N, Md Shalleh N, Rossetti C

Singapore Med J, 2008 Jul;49(7):e178-82.
PMID: 18695852

A majority of the clinical use of positron emission tomography (PET)-computed tomography (CT) is related to cancer management. Its application in evaluating inflammatory diseases and pyrexia of unknown origin is becoming popular. We reviewed the fluorine-18-fluorodeoxyglucose PET-CT findings of an 80-year-old woman with nonspecific clinical presentation consisting of generalised malaise, moderately high fever and weight loss. Prior CT and magnetic resonance imaging were not helpful in providing a clinical diagnosis. The diagnosis was Horton's arteritis, and the patient responded well to high-dose steroids.

Matched MeSH terms: Diagnostic Imaging/methods
Fulltext A Negative Index Metamaterial-Inspired UWB Antenna with an Integration of Complementary SRR and CLS Unit Cells for Microwave Imaging Sensor Applications

Islam MT, Islam MM, Samsuzzaman M, Faruque MR, Misran N

Sensors (Basel), 2015 May 20;15(5):11601-27.
PMID: 26007721 DOI: 10.3390/s150511601

This paper presents a negative index metamaterial incorporated UWB antenna with an integration of complementary SRR (split-ring resonator) and CLS (capacitive loaded strip) unit cells for microwave imaging sensor applications. This metamaterial UWB antenna sensor consists of four unit cells along one axis, where each unit cell incorporates a complementary SRR and CLS pair. This integration enables a design layout that allows both a negative value of permittivity and a negative value of permeability simultaneous, resulting in a durable negative index to enhance the antenna sensor performance for microwave imaging sensor applications. The proposed MTM antenna sensor was designed and fabricated on an FR4 substrate having a thickness of 1.6 mm and a dielectric constant of 4.6. The electrical dimensions of this antenna sensor are 0.20 λ × 0.29 λ at a lower frequency of 3.1 GHz. This antenna sensor achieves a 131.5% bandwidth (VSWR < 2) covering the frequency bands from 3.1 GHz to more than 15 GHz with a maximum gain of 6.57 dBi. High fidelity factor and gain, smooth surface-current distribution and nearly omni-directional radiation patterns with low cross-polarization confirm that the proposed negative index UWB antenna is a promising entrant in the field of microwave imaging sensors.

Matched MeSH terms: Diagnostic Imaging/instrumentation*
Fulltext Ultra-Wideband (UWB) Antenna Sensor Based Microwave Breast Imaging: A Review

Mahmud MZ, Islam MT, Misran N, Almutairi AF, Cho M

Sensors (Basel), 2018 Sep 05;18(9).
PMID: 30189633 DOI: 10.3390/s18092951

Globally, breast cancer is reported as a primary cause of death in women. More than 1.8 million new breast cancer cases are diagnosed every year. Because of the current limitations on clinical imaging, researchers are motivated to investigate complementary tools and alternatives to available techniques for detecting breast cancer in earlier stages. This article presents a review of concepts and electromagnetic techniques for microwave breast imaging. More specifically, this work reviews ultra-wideband (UWB) antenna sensors and their current applications in medical imaging, leading to breast imaging. We review the use of UWB sensor based microwave energy in various imaging applications for breast tumor related diseases, tumor detection, and breast tumor detection. In microwave imaging, the back-scattered signals radiating by sensors from a human body are analyzed for changes in the electrical properties of tissues. Tumorous cells exhibit higher dielectric constants because of their high water content. The goal of this article is to provide microwave researchers with in-depth information on electromagnetic techniques for microwave imaging sensors and describe recent developments in these techniques.

Matched MeSH terms: Diagnostic Imaging
Fulltext UWB Antenna with Enhanced Directivity for Applications in Microwave Medical Imaging

Awan D, Bashir S, Khan S, Al-Bawri SS, Dalarsson M

Sensors (Basel), 2024 Feb 18;24(4).
PMID: 38400473 DOI: 10.3390/s24041315

Microwave medical imaging (MMI) is experiencing a surge in research interest, with antenna performance emerging as a key area for improvement. This work addresses this need by enhancing the directivity of a compact UWB antenna using a Yagi-Uda-inspired reflector antenna. The proposed reflector-loaded antenna (RLA) exhibited significant gain and directivity improvements compared to a non-directional reference antenna. When analyzed for MMI applications, the RLA showed a maximum increase of 4 dBi in the realized gain and of 14.26 dB in the transmitted field strength within a human breast model. Moreover, it preserved the shape of time-domain input signals with a high correlation factor of 94.86%. To further validate our approach, another non-directional antenna with proven head imaging capabilities was modified with a reflector, achieving similar directivity enhancements. The combined results demonstrate the feasibility of RLAs for improved performance in MMI systems.

Matched MeSH terms: Diagnostic Imaging
Diagnostic radiology in the tropics: technical considerations

Ng KH, McLean ID

Semin Musculoskelet Radiol, 2011 Nov;15(5):441-5.
PMID: 22081279 DOI: 10.1055/s-0031-1293490

An estimated two thirds of the world's population is currently without access to diagnostic radiology services, and most of them live in resource-limited tropical regions with harsh environments. Most patients are diagnosed and treated in poorly equipped government-funded hospitals and clinics that have insufficiently trained staff and are barely operational. Any available imaging equipment is likely to be functioning suboptimally and be poorly maintained. The root of the problem is usually a lack of know-how and a quality culture, combined with insufficient basic equipment and infrastructure. Radiological imaging is an essential aspect of primary care and used in the critical diagnosis and management of trauma, tuberculosis, pneumonia, acquired immunodeficiency syndrome, cancer, and other respiratory and abdominal diseases. Considerations such as quality management and infrastructure, personnel, equipment, and radiation protection and safety are important to ensure the proper functioning and rational use of a diagnostic radiology facility in the tropics.

Matched MeSH terms: Diagnostic Imaging/standards*
Lymph node metastasis of primary endometrial cancers: Associated proteins revealed by MALDI imaging

Mittal P, Klingler-Hoffmann M, Arentz G, Winderbaum L, Lokman NA, Zhang C, et al.

Proteomics, 2016 06;16(11-12):1793-801.
PMID: 27061135 DOI: 10.1002/pmic.201500455

Metastasis is a crucial step of malignant progression and is the primary cause of death from endometrial cancer. However, clinicians presently face the challenge that conventional surgical-pathological variables, such as tumour size, depth of myometrial invasion, histological grade, lymphovascular space invasion or radiological imaging are unable to predict with accuracy if the primary tumour has metastasized. In the current retrospective study, we have used primary tumour samples of endometrial cancer patients diagnosed with (n = 16) and without (n = 27) lymph node metastasis to identify potential discriminators. Using peptide matrix assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI), we have identified m/z values which can classify 88% of all tumours correctly. The top discriminative m/z values were identified using a combination of in situ sequencing and LC-MS/MS from digested tumour samples. Two of the proteins identified, plectin and α-Actin-2, were used for validation studies using LC-MS/MS data independent analysis (DIA) and immunohistochemistry. In summary, MALDI-MSI has the potential to identify discriminators of metastasis using primary tumour samples.

Matched MeSH terms: Diagnostic Imaging
Fulltext Neutron Activated Samarium-153 Microparticles for Transarterial Radioembolization of Liver Tumour with Post-Procedure Imaging Capabilities

Hashikin NA, Yeong CH, Abdullah BJ, Ng KH, Chung LY, Dahalan R, et al.

PLoS One, 2015;10(9):e0138106.
PMID: 26382059 DOI: 10.1371/journal.pone.0138106

Samarium-153 (153Sm) styrene divinylbenzene microparticles were developed as a surrogate for Yttrium-90 (90Y) microspheres in liver radioembolization therapy. Unlike the pure beta emitter 90Y, 153Sm possess both therapeutic beta and diagnostic gamma radiations, making it possible for post-procedure imaging following therapy.

Matched MeSH terms: Diagnostic Imaging/methods
Fulltext Extreme learning machine based optimal embedding location finder for image steganography

Atee HA, Ahmad R, Noor NM, Rahma AM, Aljeroudi Y

PLoS One, 2017;12(2):e0170329.
PMID: 28196080 DOI: 10.1371/journal.pone.0170329

In image steganography, determining the optimum location for embedding the secret message precisely with minimum distortion of the host medium remains a challenging issue. Yet, an effective approach for the selection of the best embedding location with least deformation is far from being achieved. To attain this goal, we propose a novel approach for image steganography with high-performance, where extreme learning machine (ELM) algorithm is modified to create a supervised mathematical model. This ELM is first trained on a part of an image or any host medium before being tested in the regression mode. This allowed us to choose the optimal location for embedding the message with best values of the predicted evaluation metrics. Contrast, homogeneity, and other texture features are used for training on a new metric. Furthermore, the developed ELM is exploited for counter over-fitting while training. The performance of the proposed steganography approach is evaluated by computing the correlation, structural similarity (SSIM) index, fusion matrices, and mean square error (MSE). The modified ELM is found to outperform the existing approaches in terms of imperceptibility. Excellent features of the experimental results demonstrate that the proposed steganographic approach is greatly proficient for preserving the visual information of an image. An improvement in the imperceptibility as much as 28% is achieved compared to the existing state of the art methods.

Matched MeSH terms: Diagnostic Imaging*

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