Ultrasound-Derived Fat Fraction for Hepatic Steatosis Assessment: Prospective Study of Agreement With MRI PDFF and Sources of Variability in a Heterogeneous Population

Background: Metabolic dysfunction-associated steatotic liver disease is a growing global public health concern. Quantitative ultrasound measurements, such as ultrasound-derived fat fraction (UDFF), could provide noninvasive, cost-effective, and portable steatosis evaluation. Objective: To evaluate utility of UDFF for steatosis assessment using PDFF as reference in patients undergoing liver MRI for heterogeneous indications, and to assess UDFF variability. Methods: This prospective study included a primary analysis of 187 patients (mean age, 53.8 years; 112 men, 75 women) who underwent 3-T liver MRI for any clinical indication from December 2020 to July 2021. Patients underwent investigational proton-density fat fraction (PDFF) measurement using MR spectroscopy, and investigational ultrasound with UDFF calculation (mean of 5 intercostal measurements) within 1 hour after MRI. In a subanalysis, 21 of these patients underwent additional UDFF measurements 1, 3, and 5 hours after meal consumption. The study also included repeatability and reproducibility (R&R) analysis of 30 patients (mean age, 26.3 years; 11 men, 20 women) who underwent clinical abdominal ultrasound between November 2022 and January 2023; in these patients, three operators sequentially performed UDFF measurements. Results: In primary analysis, UDFF and PDFF showed intraclass correlation coefficient (ICC) of 0.79. In Bland-Altmananalysis, UDFF and PDFF showed mean difference of 1.5% (95% CI, 0.6-2.4%), with 95% limits of agreement from -11.0% to 14.0%. UDFF exhibited AUC for detecting PDFF at historic thresholds of ≥6.5%, ≥17.4%, and ≥22.1% of 0.90, 0.95, and 0.95, respectively. In subanalysis, mean UDFF was not significantly different across time points with respect to meal consumption (p=.21). In R&R analysis, ICC for intraoperator repeatability ranged from 0.98 to 0.99, and for interoperator reproducibility from 0.90 to 0.96. Visual assessment of patient-level data plots indicated increasing variability of mean UDFF measurements across operators, and of intercostal measurements within individual patients, with increasing steatosis. Conclusion: UDFF showed robust agreement with PDFF, diagnostic performance for steatosis grades, as well as intraoperator repeatability and interoperator reproducibility. Nonetheless, UDFF exhibited bias toward slightly larger values versus PDFF, intraoperator and interoperator variation increased with increasing steatosis. Clinical Impact: UDFF shows promise for steatosis assessment across diverse populations, although continued optimization remains warranted.

4D Volume Intracardiac Echocardiography for Intraprocedural Guidance of Transcatheter Left Atrial Appendage Closure

Background

Fluoroscopy and transesophageal echocardiography (TEE) are used to guide transcatheter left atrial appendage (LAA) closure in patients with atrial fibrillation to prevent thromboembolic events. This study examines whether real-time three-dimensional volume ICE guidance (4D volume ICE) can be used as an alternative to TEE during LAA closure (LAAC).

Methods and Results

Fifteen patients with atrial fibrillation (AF), who had high risk for stroke and contraindication for long-term warfarin therapy, were enrolled in the study. The WATCHMAN device was used for transcatheter LAAC under fluoroscopy. LAA and device sizing was performed using TEE and volume ICE guidance from the right heart. Intraprocedural ICE measurements were consistent with TEE; LAA maximal width and depth, and maximal diameter of the implanted device were moderately correlated (Pearson's coefficient: 0.63, 0.65, and 0.71 respectively; p<0.05) with good agreement (bias: -0.03 cm, -0.07 cm, and 0.003 cm respectively). The average imaging success rate, defined by the number of patients with all the required intraprocedural measurements, was 67% for ICE and 100% for TEE. The WATCHMAN device was successfully implanted in all patients with a device to patient ratio of 1.33.

Conclusions

4D volume ICE can be used as an intraprocedural sizing and guidance tool for transcatheter LAAC with measurements comparable to TEE. Challenging patient characteristics significantly degrade the diagnostic image quality when imaging from the right heart. Standardized workflow with proper patient selection and optimal preprocedural planning may improve the diagnostic quality of volume ICE guidance for transcatheter LAAC procedure.

Measurement of Wall Shear Stress Exerted by Flowing Blood in the Human Carotid Artery: Ultrasound Doppler Velocimetry and Echo Particle Image Velocimetry

Vascular endothelial cells lining the arteries are sensitive to wall shear stress (WSS) exerted by flowing blood. An important component of the pathophysiology of vascular diseases, WSS is commonly estimated by centerline ultrasound Doppler velocimetry (UDV). However, the accuracy of this method is uncertain. We have previously validated the use of a novel, ultrasound-based, particle image velocimetry technique (echo PIV) to compute 2-D velocity vector fields, which can easily be converted into WSS data. We compared WSS data derived from UDV and echo PIV in the common carotid artery of 27 healthy participants. Compared with echo PIV, time-averaged WSS was lower using UDV (28 ± 35%). Echo PIV revealed that this was due to considerable spatiotemporal variation in the flow velocity profile, contrary to the assumption that flow is steady and the velocity profile is parabolic throughout the cardiac cycle. The largest WSS underestimation by UDV was found during peak systole (118 ± 16%) and the smallest during mid-diastole (4.3± 46%). The UDV method underestimated WSS for the accelerating and decelerating systolic measurements (68 ± 30% and 24 ± 51%), whereas WSS was overestimated for end-diastolic measurements (-44 ± 55%). Our data indicate that UDV estimates of WSS provided limited and largely inaccurate information about WSS and that the complex spatiotemporal flow patterns do not fit well with traditional assumptions about blood flow in arteries. Echo PIV-derived WSS provides detailed information about this important but poorly understood stimulus that influences vascular endothelial pathophysiology.

Resistive Index of Intrarenal Artery in Evaluation of Diabetic Nephropathy

Diabetes mellitus is one of the systemic diseases affecting the kidneys. Diabetic nephropathy is a serious microvascular complication of diabetes mellitus. It is the most important,cause of death in type I diabetic patients, of whom 30%-40% eventually develop end-stage renal failure and 40% of type II diabetics are at risk of developing diabetic nephropathy. So, diagnosis of diabetic nephropathy is paramount for the survivability of the diabetic patients not only because of the consequences of renal progression but also because of the strong association with the risk of developing cardiovascular disease. A total number of 53 subjects were enrolled in this present cross sectional study in the department of Radiology and Imaging, Bangabandhu Sheikh Mujib Medical University (BSMMU) in collaboration of Nephrology and Medicine of the same institution during two years (2011-13) aim to evaluate the diagnostic usefulness of renal resistive index (RI) by duplex Doppler ultrasonography for detection of renal dysfunction in diabetic patients. Clinically diagnosed diabetic patients having diabetic nephropathy referred to the department of Radiology and Imaging in BSMMU for ultrasonography of Kidneys, Ureters and Bladder (KUB) region or whole abdomen were selected as sample. Biochemical reports (Serum creatinine and Urinary albumin) and the RI value of intrarenal artery were correlated and analyzed. Only those patients biochemically were diagnosed as having diabetic nephropathy was included. Those with incomplete data, hydro nephrosis and renal calculus were excluded. Both the kidneys were visualized by commercially available real time scanner (GE Voluson) equipped with a curvilinear transducer operating at 3.5 MHz First Gray scale ultrasonography was done followed by Color Doppler of intra renal artery and then RI was measured. Majority (45.3%) patients were in 6th decade with the mean age was of 52.66±7.4 years and ranging from 38 to 65 years in patients. Male was found to be 54.7% of diabetic patients with male to female ratio 1.2:1. Resistive index of (≥ 0.7) was found in 73.6% patients with diabetes with the mean resistive index of 0.71±0.04. Positive correction between resistive index with serum creatinine (r=0.581, p<0.01) and albuminuria (r-0.725, p<0.01) were observed. It can be concluded that Resistive Index measured by duplex Doppler ultrasonography is useful diagnostic modality for detection of renal dysfunction in diabetic nephropathy patients. Resistive Index has value in identifying diabetic patients who are developing nephropathy and can be used as an additional diagnostic tool. Also it is well correlated with Serum Creatinine and Albuminuria which are the biochemical parameters to diagnose diabetic nephropathy.

Echo Particle Image Velocimetry for Estimation of Carotid Artery Wall Shear Stress: Repeatability, Reproducibility and Comparison with Phase-Contrast Magnetic Resonance Imaging

Measurement of hemodynamic wall shear stress (WSS) is important in investigating the role of WSS in the initiation and progression of atherosclerosis. Echo particle image velocimetry (echo PIV) is a novel ultrasound-based technique for measuring WSS in vivo that has previously been validated in vitro using the standard optical PIV technique. We evaluated the repeatability and reproducibility of echo PIV for measuring WSS in the human common carotid artery. We measured WSS in 28 healthy participants (18 males and 10 females, mean age: 56 ± 12 y). Echo PIV was highly repeatable, with an intra-observer variability of 1.0 ± 0.1 dyn/cm² for peak systolic (maximum), 0.9 dyn/cm² for mean and 0.5 dyn/cm² for end-diastolic (minimum) WSS measurements. Likewise, echo PIV was reproducible, with a low inter-observer variability (max: 2.0 ± 0.2 dyn/cm², mean: 1.3 ± 0.1 dyn/cm², end-diastolic: 0.7 dyn/cm²) and more variable inter-scan (test-retest) variability (max: 7.1 ± 2.3 dyn/cm², mean: 2.9 ± 0.4 dyn/cm², min: 1.5 ± 0.1 dyn/cm²). We compared echo PIV with the reference method, phase-contrast magnetic resonance imaging (PC-MRI); echo PIV-based WSS measurements agreed qualitatively with PC-MRI measurements (r = 0.89, p < 0.05). Significant differences were observed in some WSS measurements (echo PIV vs. PC-MRI): WSS at peak systole: 21 ± 7.0 dyn/cm² vs. 15 ± 5.0 dyn/cm²; time-averaged WSS: 8.9 ± 3.0 dyn/cm² vs. 7.1 ± 3.0 dyn/cm² (p < 0.05); WSS at end diastole: 3.8 ± 2.8 dyn/cm² vs. 3.9 ± 2 dyn/cm² (p > 0.05). For the first time, we report that echo PIV can measure WSS with good repeatability and reproducibility in adult humans with a broad age range. Echo PIV is feasible in humans and offers an easy-to-use, ultrasound-based, quantitative technique for measuring WSS in vivo in humans with good repeatability and reproducibility.

Comparative Study of Prevalence of Cataract at High Altitude and Kathmandu Valley

BACKGROUND

Cataract is the leading cause of avoidable blindness in the world. Many etiological and risk factors for age related cataract has been documented. The present study is conducted to compare the prevalence of cataract at high altitude and Kathmandu valley.Many etiological and risk factors for age related cataract has been documented.

METHODS

A cross sectional comparative study was conducted at Jomsom, Kagbeni, Jharkot and Muktinath of Mustang district and Balaju and Jawalakhel of Kathmandu valley of Nepal in 2009 to 2011 . There were 222 participants at Mustang and186 participants at Kathmandu. The prevalence of cataract was studied among the Tibetans and Thakali population at Mustang and Tibetans at Jawalakhel and Thakali population at Balaju of Kathmandu valley.

RESULTS

Prevalence of cataract at high altitude was 31.5% and 10.2% at Kathmandu valley. The prevalence of cataract is 4.05 times more at high altitude as compared to Kathmandu valley (p value < 0.001).

CONCLUSIONS

The prevalence of cataract was significantly high at high altitude as compared to lower altitude.

Exhaled Breath Analysis in Tuberculosis Case Detection: The New Horizon

Sixty years ago, Nobel Prize winner Linus Pauling proposed the concept that human breath is a complex and dynamic gaseous mixture of more than 200 different endogenous volatile organic compounds (VOCs) that are continually being released in different quantities within the internal environment during health and disease. The researchers estimate that more than a thousand chemicals produced in different organ-systems as metabolic end products come out every minute through the respiratory tract. Volatile organic compounds and other products of oxidative stress are a big chunk among these exhaled breath elements.DOI: http://doi.dx.org/10.3126/nje.v3i2.8509

Abstract 246: Echo Particle Image Velocimetry Generates Wall Shear Stress Biomarkers with Higher Accuracy than Doppler: Clinical Studies on 24 Healthy and 12 Tia Subjects

Wall shear stress (WSS) is an important modulator of vascular disease. We assessed the hypothesis that WSS profiles derived from Echo Particle Image Velocimetry (EchoPIV) are characteristic of vascular conditions such as TIA with superior accuracy to Doppler. We obtained ultrasound images of CCA from 24 healthy and 12 TIA subjects. Doppler provided centerline peak velocity and WSS estimate based on parabolic velocity distribution. Velocity profiles measured by EchoPIV varied from patient to patient and within the cardiac cycle. Curve-fitting to a power law function with an exponent term (n-value) showed that in healthy carotid arteries, a blunt velocity profile is present during systole with an average n-value of 5, whereas during diastole a more parabolic profile with an n-value of 2 is present. Therefore, assuming a fully parabolic velocity distribution for WSS estimation, the basis for Doppler velocimetry, introduces a mean error of 48% during diastole and 98% during systole. EchoPIV offers characterization of WSS profiles; time waveform analysis revealed smoother and fewer number of peaks per cycle for healthy and increased flow pulsatality (reverberations) for TIA (Figure). Echo PIV generated means for phase averaged peak velocity (27.95 vs 16.13 cm/s), WSS (6.45 vs 4.65 Dynes/cm2) and flow rate (0.3179 vs 0.2215 L/min) with standard deviations 3.66 vs 2.35, 2.8 vs 1.74 and 0.0723 vs 0.0744 were significantly different between healthy and TIA subjects respectively (all p < 0.01). Direct measurement of the velocity profile using Echo PIV provides superior estimates of WSS in carotid vessels. TIA populations have compromised hemodynamic variables compared to healthy subjects.

Computerized lung sound analysis as diagnostic aid for the detection of abnormal lung sounds: a systematic review and meta-analysis

RATIONALE

The standardized use of a stethoscope for chest auscultation in clinical research is limited by its inherent inter-listener variability. Electronic auscultation and automated classification of recorded lung sounds may help prevent some of these shortcomings.

OBJECTIVE

We sought to perform a systematic review and meta-analysis of studies implementing computerized lung sound analysis (CLSA) to aid in the detection of abnormal lung sounds for specific respiratory disorders.

METHODS

We searched for articles on CLSA in MEDLINE, EMBASE, Cochrane Library and ISI Web of Knowledge through July 31, 2010. Following qualitative review, we conducted a meta-analysis to estimate the sensitivity and specificity of CLSA for the detection of abnormal lung sounds.

MEASUREMENTS AND MAIN RESULTS

Of 208 articles identified, we selected eight studies for review. Most studies employed either electret microphones or piezoelectric sensors for auscultation, and Fourier Transform and Neural Network algorithms for analysis and automated classification of lung sounds. Overall sensitivity for the detection of wheezes or crackles using CLSA was 80% (95% CI 72-86%) and specificity was 85% (95% CI 78-91%).

CONCLUSIONS

While quality data on CLSA are relatively limited, analysis of existing information suggests that CLSA can provide a relatively high specificity for detecting abnormal lung sounds such as crackles and wheezes. Further research and product development could promote the value of CLSA in research studies or its diagnostic utility in clinical settings.

Effective control of hypertension in adults with chronic kidney disease

INTRODUCTION: Adequate control of hypertension in Chronic Kidney Disease patients is difficult to achieve. This study was designed to analyze the adequacy of Hypertension control in adults with CKD using different classes of antihypertensive drugs. METHODS: A cross-sectional observational study was done that included 85 patients with CKD admitted to our Medicine Department over a period of two years (2006-2008 A.D.). Presence of CKD was defined as glomerular filtration rate <60 ml/min per 1.73 m2 for more than three months or presence of albuminuria (albumin:creatinine ratio >30ug/mg). Adequate blood pressure control was defined as systolic blood pressure less than or equals to 130 and diastolic blood pressure less than or equals to 80 mm Hg. Data and Statistical analysis was done using SPSS Version 12 for Windows. RESULTS: Of all the CKD patients, 51.4% required three Anti-Hypertensive drugs combination for the effective control of Hypertension, while only 21% of CKD patients with hypertension was controlled on two drugs. CONCLUSION: Adequate control of blood pressure in CKD patient was shown to be most effective on combination of three antihypertensive drugs. A poor control was seen on patients taking less than three antihypertensive drugs. Keywords: antihypertensive drug; chronic kidney disease; glomerular filtration rate; hypertension.

Effective control of hypertension in adults with chronic kidney disease

INTRODUCTION

Adequate control of hypertension in Chronic Kidney Disease patients is difficult to achieve. This study was designed to analyze the adequacy of Hypertension control in adults with CKD using different classes of antihypertensive drugs.

METHODS

A cross-sectional observational study was done that included 85 patients with CKD admitted to our Medicine Department over a period of two years (2006-2008 A.D.). Presence of CKD was defined as glomerular filtration rate <60 ml/min per 1.73 m2 for more than three months or presence of albuminuria (albumin:creatinine ratio >30ug/mg). Adequate blood pressure control was defined as systolic blood pressure less than or equals to 130 and diastolic blood pressure less than or equals to 80 mm Hg. Data and Statistical analysis was done using SPSS Version 12 for Windows.

RESULTS

Of all the CKD patients, 51.4% required three Anti-Hypertensive drugs combination for the effective control of Hypertension, while only 21% of CKD patients with hypertension was controlled on two drugs.

CONCLUSION

Adequate control of blood pressure in CKD patient was shown to be most effective on combination of three antihypertensive drugs. A poor control was seen on patients taking less than three antihypertensive drugs.

Toxicity of antibiotics and antifungals on cultured human corneal cells: effect of mixing, exposure and concentration

Toxic effects of topical drugs may be masked by manifestations of the disease they cure. The toxicity of drug mixtures has not been thoroughly studied. We therefore investigated cytopathic effects on primary cultures of human corneal cells of six topical antimicrobials singly and in combinations of any two, to determine the combined toxicity ranking and the interaction between duration of exposure and concentration. Preconfluent cultures were exposed to fixed dilutions of single drugs, or to equal-dilution mixtures of two drugs, for 7 and 14 days. Diminishing concentrations of single drugs were applied sequentially to cultures for 14 days. The number of metabolically competent cells was assessed by measuring hexosaminidase and total protein. Toxic effects depended on substance, concentration and exposure. The scale of toxicity determined for single drugs after 7 days of exposure was: gentamicin > econazole > or = methicillin > or = clotrimazole > or = miconazole > or = chloramphenicol. After 14 days this order changed: in particular chloramphenicol showed a highly increased toxicity. The order of diminishing effects was: gentamicin > chloramphenicol > or = methicillin > miconazole > econazole > clotrimazole. A clear reduction in cytopathic effects was observed when drug concentration was decreased progressively only in cultures treated with gentamicin or methicillin. All drug combinations were more toxic than their components at equal dilution. Combinations containing chloramphenicol ranked most toxic overall, those containing econazole least. A tapering off combination regime did not improve cell survival. These in vitro toxicity data complement clinical studies and suggest ways in which topical drugs can be chosen to minimise toxic effects to corneal surface.

Visual outcome of conventional extracapsular cataract extraction with posterior chamber intraocular lens implantation versus manual small-incision cataract surgery

Background: An effective method for cataract surgery should be identified to combat cataract blindness. Aim: To study the surgical outcome of conventional extracapsular cataract extraction versus manual small-incision cataract surgery. Materials and methods: A randomized clinical trial was carried out including one hundred eyes (88 patients) which were divided into two groups using systematic randomization: groups of conventional extracapsular cataract extraction with posterior chamber intraocular lens (ECCE with PCIOL) implantation and manual small-incision cataract surgery (MSICS). The postoperative parameters/variables studied were the unaided and best-corrected visual acuity and astigmatism. Statistics: Epi info 2000 version statistical software was used for data analysis and calculation of relative risk, 95% CI and p value. The p value of less than 0.05 was considered as significant. Results: In the immediate postoperative period, unaided visual acuity of =/> 6/18 was achieved in 24 subjects in MSICS group versus 7 in ECCE with PCIOL group (RR=2.05, 95% CI=1.44 - 2.94, p = 0.0002), whereas the same at 6 - 8 weeks postoperatively was found in 28 and 22 subjects in those groups respectively (RR=1.27, 95% CI=0.86-1.89, p=0.23). The astigmatism of =/> 2 at 6 - 8 weeks was found in 35 and 17 subjects from the conventional and MSICS groups respectively ( R=2.28, 95% CI = 1.39-3.73, p=0.0002). Conclusion: Both MSICS and conventional ECCE with PCIOL are safe and effective techniques for treatment of cataract patients. A more rapid recovery of good vision can be achieved with MSICS than with conventional ECCE with PCIOL in the immediate postoperative period. Key words: ECCE; MSICS; visual acuity; astigmatism DOI: 10.3126/nepjoph.v1i1.3668 Nep J Oph 2009;1(1):13-19

Pattern of Ophthalmological Diseases in the Patients of Shree Birendra Hospital

Introduction: Blindness is one of the most tragic yet often avoidable disabilities in the developing world. The pattern of ocular diseases varies in different parts of Nepal due to differences in socioeconomic and geographic factors. This retrospective study likely reflects the pattern of ocular diseases in Kathmandu Valley. Aim: To assess the patterns of ocular disease in the patients attending the outpatient department of Ophthalmology from 14th April 2009 to 13th April 2010 at the Army Hospital. Methods: This is a retrospective study and all the new cases which attended the department of Ophthalmology of Shree Birendra Hospital in the year 2066 were included. The diseases were divided into 11 groups i.e. lid & adenexal disorder, disease of conjunctiva & sclera, corneal diseases, lens associated disorders, diseases of uveal tract, refractive error, glaucoma & its associations, posterior segment diseases, ocular & systemic neoplastic disorders, Nekebadi (annual medical check up) and others. Result: The total number of patients recorded in the department of Ophthalmology is 16709. Among them 4473 were regular serving army personnel and 12236 were ex-army and army families. Conclusion: The pattern of eye disease varies in different age groups. In younger age group conjunctival, scleral disease and refractive error were commonly seen whereas in elder age group lens disorder was frequently seen. The number of blind patients was more in females than in male patients. Key words: Conjunctivitis; Cataract; Blindness. DOI: http://dx.doi.org/10.3126/mjsbh.v9i2.5023 Medical Journal of Shree Birendra Hospital Vol.9(2) 2010: 30-37