Rare Manifestation of COVID-19 Resulting in Coronary Artery Vasculitis.

We present the case of a 59-year-old African American female with end-stage renal disease (ESRD) who presented to the emergency department with chest discomfort. She had a coronary angiogram six months ago that showed no occlusive epicardial coronary artery disease. She had elevated troponin I levels and new regional wall motion abnormalities on echocardiogram. Her SARS-CoV-2 returned positive. After a multidisciplinary team approach, she underwent another coronary angiogram that showed new severe multivessel ostial lesions and a left main coronary artery aneurysm. COVID-19-related coronary artery vasculitis was suspected based on her clinical presentation, angiogram findings, and negative autoimmune workup. The patient underwent successful coronary artery bypass grafting and recovered without complications.

Outcomes of transcatheter aortic valve replacement in patients with mitral annular calcification and concomitant mitral valve dysfunction: A systematic review and meta-analysis.

BACKGROUND: Calcific aortic stenosis is the principal indication for transcatheter aortic valve replacement (TAVR). Comorbid mitral annular calcification (MAC) is often present in patients undergoing TAVR. Limited data exist on the impact of MAC on TAVR outcomes. We conducted a systematic review and meta-analysis to explore the effects of MAC and concomitant mitral valve dysfunction (MVD) on TAVR outcomes. METHODS: A comprehensive literature review was conducted using PubMed, Embase, Google Scholar, ClinicalTrials.gov, Scopus, and OVID for studies until March 20, 2023. Using the random-effects Mantel-Haenszel method, we calculated pooled risk ratios (RRs) and their corresponding 95 % confidence intervals (CIs) for all dichotomous variables. RESULTS: Six studies comprising 5822 patients (2541 with MAC [severe MAC (>4 mm thickness) 583; non-severe MAC 1958; 400 with MVD; and 1071 without MVD], 3281 without MAC) met inclusion criteria. At 30 days and 1 year, no significant differences were observed between the overall MAC and no MAC groups in terms of mortality, stroke, and permanent pacemaker implantation. However, MAC with MVD was associated with a higher risk of all-cause mortality compared to MAC without MVD at 30 days (RR = 3.43, 95 % CI 2.04-5.76, P < 0.00001) and at 1 year (RR = 2.44, 95 % CI 1.85-3.20, P < 0.00001). Moreover, the risk of cardiovascular mortality was higher in patients with MAC and MVD compared to those with MAC alone (RR = 2.77, 95 % CI 1.89-4.06, P < 0.00001). Additionally, patients with severe MAC had a higher risk of major bleeding at 30 days compared to the non-severe MAC group (RR = 1.33, 95 % CI 1.04-1.69, P = 0.02). CONCLUSION: TAVR appears to be safe in patients with non-severe MAC, but severe MAC is associated with a higher risk of major bleeding and concomitant MVD increases the mortality risk in patients undergoing TAVR.

Long-Term Major Adverse Cardiovascular Events in Patients "Appropriately" Tested for Troponin Assays in Emergency Department.

Cardiac biomarkers like troponin have become essential for detecting myocardial ischemia, a hallmark of the acute coronary syndrome (ACS), in the emergency department (ED). However, inappropriate and excessive biomarker testing can lead to false positive results, patient anxiety, and unnecessary treatment. Our study aimed to develop an appropriateness criterion for troponin testing and examine the long-term major adverse cardiac events (MACE) of patients tested with troponin in the ED. We retrospectively evaluated 407 patients who underwent troponin testing at a tertiary-care northeastern US hospital. The majority (n = 252, 62%) of troponin testing was appropriate, with the remainder deemed inappropriate. Baseline characteristics were equally distributed between the 2 groups. Of the appropriately ordered troponins, 34% were positive compared to 28% of the inappropriately ordered troponins (range 0.04-0.10 ng/mL). Patients were followed over 540 days. MACE occurred in 21% and 10% of patients in the appropriate and inappropriate groups, respectively. Unlike the inappropriate group (3.5%), 96% of the events in the appropriate group occurred within the first 200 days. Patients in the appropriate group were at an increased adjusted risk of MACE (HR 2.55, 95% CI (1.59-4.08), P < 0.001) on long-term follow-up. In addition, MACE was comparable between patients with positive and negative troponins in the inappropriate group (HR 1.46, 95% CI (0.28-7.71), P = 0.65). Our study supports judicious troponin testing and the need for robust appropriateness criteria for ordering troponin in the ED to avoid overdiagnosis and inappropriate testing.

Unraveling a rare presentation of bivalvular infective endocarditis using POCUS.

Infective endocarditis (IE) is rare, and involvement of two valves is rarer yet. We present a case of a 22-year-old male with liver failure who was found to have bivalvular IE. This case sheds light on the association between bivalvular IE and seemingly unrelated symptoms, emphasizing the need for early recognition.

Beyond the norm: A rare case of cardiac and extracardiac metastatic urothelial carcinoma.

Screening echocardiography aids in identifying cardiac emboli causes and asymptomatic cardiac metastases in high-grade neoplasms. Conversely, cardiac MRI provides advanced tissue characterization and broader extracardiac assessment.

Association of potato consumption with calcified atherosclerotic plaques in the coronary arteries: The NHLBI Family Heart Study.

BACKGROUND AND AIMS: While the association of potato consumption with risk factors for coronary artery disease has been inconsistent, no data are available in the literature on the influence of potato consumption on subclinical disease. Thus, we sought to examine whether baked/mashed potato consumption is associated with calcified atherosclerotic plaques in the coronary arteries. METHODS AND RESULTS: In a cross-sectional design, we studied 2208 participants of the NHLBI Family Heart Study. These subjects were selected based on their elevated cardiovascular disease risk compared to the general population. Potato consumption was assessed by a semi-quantitative food frequency questionnaire. We defined prevalent CAC using an Agatston score of at least 100 and fitted generalized estimating equations to calculate prevalence odds ratios of CAC. Mean age at initial clinic visit was 58.2 years and 55% were female. Median consumption of potatoes was 2-4/week. There was no statistically significant association between frequency of potato consumption and prevalent CAC: odds ratios (95% CI) for CAC were 1.0 (reference), 0.85 (0.56-1.30), 0.85 (0.58-1.26), and 0.95 (0.60-1.53) among subjects reporting potato consumption of <1/week, 1/week, 2-4/week, and 5+/week, respectively (p for linear trend 0.83), adjusting for age, sex, BMI, smoking, exercise, diabetes, hypertension, total calories, prevalent coronary heart disease, income, education, and daily red meat intake. CONCLUSIONS: We found no significant association between baked/mashed potato consumption and CAC in older adults. STUDY REGISTRATION NUMBER: NCT00005136. Study registration date: 5/25/2000.

Intracranial metastasis from prostate adenocarcinoma: a case report and literature review.

Intracranial metastasis from prostate adenocarcinoma is rare. A 70-year-old African American male with a history of prostate adenocarcinoma for the last 14 years, presented to our hospital complaining of generalized weakness for the past 2 weeks. He was found to have fever with left ptosis and mild eyelid edema. Brain MRI showed dural metastasis. Two months after the first presentation, he was readmitted with a suspected acute cerebral vascular accident (CVA). CT brain showed vasogenic edema in the right subcortical, likely from intracranial metastasis. His acute neurological symptoms improved with intravenous dexamethasone. This case highlights the possibility of intracranial metastasis from prostate adenocarcinoma. With the advent of novel therapies for prostate cancer, which prolong life expectancy, intracranial metastasis from prostate adenocarcinoma may become an increasingly frequent clinical scenario.

Study of the Effect of Different Hepatitis C Virus Genotypes on Splenomegaly.

Background Several recent studies have shown that the hepatitis C virus (HCV) and its different genotypes are a predominant and leading cause of cirrhosis and splenomegaly in different regions of the world. Advanced stage of cirrhosis leads to portal hypertension that causes splenomegaly. This complication may have many other manifestations such as anemia, infections, and bleeding disorders in severe stages. This study aimed to determine the effect of different HCV genotypes on the development of splenomegaly and to assess which HCV genotypes are more associated with it. Materials and methods A total of 483 conveniently sampled HCV patients were included in this descriptive cross-sectional study. Six genotypes (1, 2a, 2b, 3a, 3b, and mixed) were studied, and 80 patients for each of these genotypes were included. Data were collected from patient medical records regarding patient demographic details, HCV serology and genotyping, and sonographic size of the spleen. Results In total, splenomegaly was present in 14.1% (n=68) patients. The development of splenomegaly was significantly associated with old age, as 25.2% (n=26) of patients above 60 years of age (n=103) developed splenomegaly (P=0.005). Our study determined that splenomegaly was significantly related to HCV genotypes 3a, 3b, and 1 (P<0.001, P=0.017, and P=0.019, respectively). By taking mixed genotype as a reference, the odds of developing splenomegaly with genotype 3a were the highest (OR = 9.481; CI=95%). Conclusions Our study concludes that HCV genotype 3a, 3b, and 1, and age above 60 years have a significant association with splenomegaly. Genotype 3a has the highest risk of developing splenomegaly. Therefore, our study demands screening, early diagnosis, and prompt treatment of these particular HCV genotypes to prevent complications and risk of mortality.

Long-term clinical outcomes in survivors of severe acute respiratory syndrome and Middle East respiratory syndrome coronavirus outbreaks after hospitalisation or ICU admission: A systematic review and meta-analysis.

OBJECTIVE: To determine long-term clinical outcomes in survivors of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronavirus infections after hospitalization or intensive care unit admission. DATA SOURCES: Ovid MEDLINE, EMBASE, CINAHL Plus, and PsycINFO were searched. STUDY SELECTION: Original studies reporting clinical outcomes of adult SARS and MERS survivors 3 months after admission or 2 months after discharge were included. DATA EXTRACTION: Studies were graded using the Oxford Centre for Evidence-Based Medicine 2009 Level of Evidence Tool. Meta-analysis was used to derive pooled estimates for prevalence/severity of outcomes up to 6 months after hospital discharge, and beyond 6 months after discharge. DATA SYNTHESIS: Of 1,169 identified studies, 28 were included in the analysis. Pooled analysis revealed that common complications up to 6 months after discharge were: impaired diffusing capacity for carbon monoxide (prevalence 27%, 95% confidence interval (CI) 15­45%); and reduced exercise capacity (mean 6-min walking distance 461 m, CI 450­473 m). The prevalences of post-traumatic stress disorder (39%, 95% CI 31­47%), depression (33%, 95% CI 20­50%) and anxiety (30%, 95% CI 10­61) beyond 6 months after discharge were considerable. Low scores on Short-Form 36 were identified beyond 6 months after discharge. CONCLUSION: Lung function abnormalities, psychological impairment and reduced exercise capacity were common in SARS and MERS survivors. Clinicians should anticipate and investigate similar long-term outcomes in COVID-19 survivors.

Relationship of left ventricular and atrial dimensions with moderate to severe left ventricular diastolic dysfunction (grade II and above).

INTRODUCTION: Left ventricular diastolic dysfunction (DD) is an entity in which the ventricle fails to fill up properly due to impaired ventricular relaxation and/or decreased compliance. The diagnosis of diastolic dysfunction is based on a variety of parameters in doppler echocardiograpy. However, some parameters like interventricular septal thickness in diastole (IVSd), posterior wall thickness in diastole (PWd), left ventricular internal end diastolic and systolic diameters (LVIDD and LVISD) along with left atrial diameters (LAD) have yet to be evaluated for the diagnostic workup of DD. METHODS: A case control study was done in the cardiology department from patient records from 2016 to 2018. Patients were diagnosed as diastolic dysfunction grade II and above by doppler echocardiography. IVSd, PWd, LVIDD, LAD, LVISD were obtained through 2-D echocardiography. RESULTS: Patients with DD had greater LAD, IVSd and PWd and decreased LVIDD and LVISD as compared to control group. Overall, IVSD was the most significant predictor (OR 1.52 95%CI 1.35-1.71) of DD followed by PWd and LAD. Similarly, LAD, IVSd and PWd had higher sensitivity and specificity than LVIDD and LVIDS. CONCLUSION: IVSd, LAD and PWd showed significant performance in the diagnosis of diastolic dysfunction and hence can be used as a screening and diagnostic tool in diastolic dysfunction of grade ll and above.

Compliance Rate of Surgical Antimicrobial Prophylaxis and its Association with Knowledge of Guidelines Among Surgical Residents in a Tertiary Care Public Hospital of a Developing Country.

Introduction Surgical antimicrobial prophylaxis (SAP) means the administration of antibiotics in surgical practice, and it reduces the likelihood of surgical site infections (SSIs). Inappropriate SAP practice regarding the prescription, timing, and duration of antibiotic use prolongs the hospital stay of patients, increases patient morbidity (by exposing them to the adverse effects of antibiotics), promotes bacterial resistance, and puts an economic burden on health care. While developed countries regularly monitor and revise their SAP protocols, there are only a few such researches in developing countries, which is a major setback to proper surgical care. Objectives of the study This study aims to compare the practice of SAP in a tertiary health care hospital of a developing country Pakistan, with internationally recommended protocols and evaluate the impact of knowledge of international guidelines on SAP practice. The results of the study will highlight important shortcomings in prophylactic practice in the hospital and help develop recommendations to improve SAP practice and ensure better surgical care for patients. Materials and methods An observational, cross-sectional study was conducted in the general surgery unit of Holy Family Hospital (HFH), Rawalpindi, Pakistan, from March 2017 to November 2017 during which antimicrobial prophylaxis of 150 general surgery procedures was documented on the basis of six international SAP criteria, which were "indication for use of prophylaxis, timing of preoperative dose, choice of drug, route of administration, duration of postoperative prophylaxis, and the assessment of beta-lactam allergy." The compliance rate (number of procedures following all the six criteria) was calculated for each operating surgical resident. A questionnaire was formulated that assessed the knowledge of 33 surgical residents working at that time regarding the above- mentioned six variables of SAP by six close-ended questions. Their responses were then compared to their compliance rate by chi-square analysis and binary logistic regression in SPSS version 23 (IBM Corp, Armonk, NY, US). A p-value of less than or equal to 0.05 was considered significant. The required ethical approval was obtained from the departmental heads as well as institutional research forum. Results Seventy-four of 150 observed procedures followed all the six international criteria of SAP, giving a compliance rate of 49.33%. Seventeen out of 33 (51%) surgical residents were aware of the guidelines. A chi-square analysis revealed a highly significant association between the awareness of guidelines and the number of compliant procedures performed by a resident (p<0.000). Forty-five out of 74 compliant procedures were performed by residents who were aware of the guidelines (61% of compliant procedures). The odds ratio for awareness and correct prophylaxis was 4.064 (p<0.000). Conclusions The study indicates an overall low compliance rate of 49.33% regarding surgical antimicrobial prophylaxis (SAP) practice in a public health care hospital of a developing country. The most common cause of non-compliance was prolonged postoperative prophylaxis. This study also shows that the knowledge of international guidelines significantly improves the prophylaxis practice by about four times. Hence, proper SAP compliance rate can be increased by actively educating and monitoring surgical residents.

Frequency and features of nocturnal enuresis in Pakistani children aged 5 to 16 years based on ICCS criteria: a multi-center cross-sectional study from Karachi, Pakistan.

BACKGROUND: Nocturnal enuresis (NE) is a common symptom in children worldwide. International Children's Continence Society (ICCS) defines enuresis as either mono-symptomatic, NE with lower urinary tract symptoms and NE with co-morbid conditions. The objectives of this study were to determine the frequencies and types of NE and associated symptoms and conditions in children aged 5 to 16 years based on ICCS criteria. METHODS: A multi-center cross sectional study was conducted between November 2012 and December 2013 in the primary care clinics of four hospitals in Karachi. Children aged five to fifteen years were included through consecutive sampling. Informed consent was obtained from the parents and a pre-coded semi-structured questionnaire was used to obtain the information. Data was entered on SPSS version 20.0 and multivariable logistic regression analysis was used for data analysis. RESULTS: Out of 429 children aged between five and sixteen years, 243(56.9%) were boys and the remaining 186(43.1%) were girls. One hundred and eighty three children (43%) had nocturnal enuresis (NE). Forty four (10.3%), had mono-symptomatic NE, 57(31.1%) had associated lower urinary tract symptoms (NE-LUTS), whereas 30 (16.3%) had NE with a co-morbid condition. Fifty two (28.4%) NE's had at least one of both LUTS and a co-morbid condition. Out of the 246(57%) non-enuretic's, 31(12.6%) had a LUTS, 95(38.6%) had a co-morbid condition and 57(23.2%) had at least one of both LUTS and a co-morbid condition. The remaining 63 (25.6%) were symptom free. Increased voiding frequency, urgency, dysuria, suprapubic pain and daytime incontinence were the LUTS significantly associated with NE. Co-morbid conditions significantly associated with NE included constipation, congenital defects, developmental delay, and learning and sleep problems. CONCLUSION: Although NE can be an only symptom, it is often associated with lower urinary tract symptoms like dysuria, urgency, suprapubic pain, and daytime incontinence. Children presenting with NE often have co-morbid conditions like constipation, urinary tract infection, sleep disorders, and developmental delay. Many children presenting with these conditions as the primary complaint may also have NE. It should be addressed as unrecognized and untreated NE can cause additional morbidity and distress.

Effect of Ramadan fasting on glucose level, lipid profile, HbA1c and uric acid among medical students in Karachi, Pakistan.

To assess the effect of Ramadan fasting on blood pressure, fasting glucose, lipid profile, uric acid, HbA1c, body mass index, body adiposity index and visceral adiposity index among fasting medical students, 35 students were recorded before, during and after Ramadan (August) 2011, for their blood pressure, anthropometric measurements, questionnaire response and blood sample. A blood sample was taken at each visit for glucose, lipid profile and HbA1c. Total physical activity, weight-to-height ratio, body adiposity index and visceral adiposity index were calculated for insulin sensitivity. Changes in anthropometric measurements were not statistically significant. However, physical activities increased significantly after Ramadan. Changes in blood pressure, fasting blood sugar, total cholesterol, HbA1c, uric acid and triglyceride were not statistically significant. Mean high density lipoprotein decreased significantly in Ramadan, while low density lipoprotein increased significantly.

Quantification of blood-brain barrier permeability by dynamic contrast-enhanced NIRS.

The blood-brain barrier (BBB) is integral to maintaining a suitable microenvironment for neurons to function properly. Despite its importance, there are no bedside methods of assessing BBB disruption to help guide management of critical-care patients. The aim of this study was to demonstrate that dynamic contrast-enhanced (DCE) near-infrared spectroscopy (NIRS) can quantify the permeability surface-area product (PS) of the BBB. Experiments were conducted in rats in which the BBB was opened by image-guided focused ultrasound. DCE-NIRS data were acquired with two dyes of different molecular weight, indocyanine green (ICG, 67 kDa) and 800CW carboxylate (IRDye, 1166 Da), and PS maps were generated by DCE computer tomography (CT) for comparison. Both dyes showed a strong correlation between measured PS values and sonication power (R2 = 0.95 and 0.92 for ICG and IRDye respectively), and the PS values for IRDye were in good agreement with CT values obtained with a contrast agent of similar molecular weight. These proof-of-principle experiments demonstrate that DCE NIRS can quantify BBB permeability. The next step in translating this method to critical care practice will be to adapt depth sensitive methods to minimize the effects of scalp contamination on NIRS PS values.

Effect of Ramadan fasting on glucose level, lipid profile, HbA1c and uric acid among medical students in Karachi, Pakistan

To assess the effect of Ramadan fasting on blood pressure, fasting glucose, lipid profile, uric acid, HbA1c, body mass index, body adiposity index and visceral adiposity index among fasting medical students, 35 students were recorded before, during and after Ramadan [August] 2011, for their blood pressure, anthropometric measurements, questionnaire response and blood sample. A blood sample was taken at each visit for glucose, lipid profile and HbA1c. Total physical activity, weight-to-height ratio, body adiposity index and visceral adiposity index were calculated for insulin sensitivity. Changes in anthropometric measurements were not statistically significant. However, physical activities increased significantly after Ramadan. Changes in blood pressure, fasting blood sugar, total cholesterol, HbA1c, uric acid and triglyceride were not statistically significant. Mean high density lipoprotein decreased significantly in Ramadan, while low density lipoprotein increased significantly

Afin de mesurer les effets du jeûne du Ramadan sur la tension artérielle, la glycémie à jeun, le profil lipidique, l'acide urique, l'hémoglobine glyquée [HbA1c], l'indice de masse corporelle, l'indice d'adiposité corporelle et l'indice d'adiposité viscérale d'étudiants en médecine pratiquant le jeûne, 35 étudiants ont été évalués avant, pendant et après Ramadan [août] 2011. Leur pression artérielle a été contrôlée, les mesures anthropométriques ont été prises, un questionnaire leur a été remis et des analyses de sang ont été réalisées. Des prélèvements sanguins ont été effectués à chaque visite pour mesurer le glucose, le profil lipidique et l'HbA1c. L'activité physique totale, le rapport poids-taille, l'indice d'adiposité corporelle et l'indice d'adiposité viscérale ont été calculés pour déterminer la sensibilité à l'insuline. Les changements au niveau des mesures anthropométriques n'étaient pas statistiquement significatifs. En revanche, l'activité physique connaissait une nette augmentation après le Ramadan. Les changements au niveau de la pression artérielle, de la glycémie à jeun, du cholestérol total, de l'HbA1c, de l'acide urique et des triglycérides n'étaient pas significatifs d'un point de vue statistique. Les lipoprotéines de haute densité moyennes baissaient significativement pendant le Ramadan, au contraire des lipoprotéines de basse densité qui augmentaient considérablement

Assessment Of Preanalytical Blood Sampling Errors In Clinical Settings.

BACKGROUND: Blood sampling is one of the common procedures done in every ward for disease diagnosis and prognosis. Daily hundreds of samples are collected from different wards but lack of appropriate knowledge of blood sampling by paramedical staff and accidental errors make the samples inappropriate for testing. Thus the need to avoid these errors for better results still remains. We carried out this research with an aim to determine the common errors during blood sampling; find factors responsible and propose ways to reduce these errors. METHODS: A cross sectional descriptive study was carried out at the Military and Combined Military Hospital Rawalpindi during February and March 2014. A Venous Blood Sampling questionnaire (VBSQ) was filled by the staff on voluntary basis in front of the researchers. The staff was briefed on the purpose of the survey before filling the questionnaire. Sample size was 228. Results were analysed using SPSS-21. RESULTS: When asked in the questionnaire, around 61.6% of the paramedical staff stated that they cleaned the vein by moving the alcohol swab from inward to outwards while 20.8% of the staff reported that they felt the vein after disinfection. On contrary to WHO guidelines, 89.6% identified that they had a habit of placing blood in the test tube by holding it in the other hand, which should actually be done after inserting it into the stand. Although 86% thought that they had ample knowledge regarding the blood sampling process but they didn't practice it properly. CONCLUSIONS: Pre analytical blood sampling errors are common in our setup. Eighty six percent participants though thought that they had adequate knowledge regarding blood sampling, but most of them were not adhering to standard protocols. There is a need of continued education and refresher courses.

Clinical Use of Diuretics in Heart Failure, Cirrhosis, and Nephrotic Syndrome.

Diuretics play significant role in pharmacology and treatment options in medicine. This paper aims to review and evaluate the clinical use of diuretics in conditions that lead to fluid overload in the body such as cardiac failure, cirrhosis, and nephrotic syndrome. To know the principles of treatment it is essential to understand the underlying pathophysiological mechanisms that cause the need of diuresis in the human body. Various classes of diuretics exist, each having a unique mode of action. A systemic approach for management is recommended based on the current guidelines, starting from thiazides and proceeding to loop diuretics. The first condition for discussion in the paper is cardiac failure. Treatment of ascites in liver cirrhosis with spironolactone as the primary agent is highlighted with further therapeutic options. Lastly, management choices for nephrotic syndrome are discussed and recommended beginning from basic sodium restriction to combined diuretic therapies. Major side effects are discussed.

Reviving a ghost in the history of technology: the social construction of the recumbent bicycle.

Recumbent bicycles have never truly been associated with international cycling. Conventional safety (upright) bicycles have long been at the center of the cycling world, for both sport and transportation. This is despite the fact that recumbent bicycles are faster, more comfortable, and more efficient than the upright bicycles. The aim of this article is to explain the historical and social perspectives that led to the rejection of the recumbent bicycle by utilizing the theory of Social Construction of Technology (SCOT) and Bijker's two power theory, providing a contrast with the adoption of the safety bicycle.

Quantitative evaluation of hyperpolarized helium-3 magnetic resonance imaging of lung function variability in cystic fibrosis.

RATIONALE AND OBJECTIVES: To better understand imaging measurement precision and reproducibility and to provide guidance for measurements in individual cystic fibrosis (CF) subjects, we evaluated CF adults on two occasions 7 ± 2 days apart using spirometry, plethysmography, and hyperpolarized helium-3 ((3)He) magnetic resonance imaging (MRI). MATERIALS AND METHODS: Twelve CF subjects underwent spirometry, plethysmography, and (3)He MRI twice within 7 ± 2 days, reporting (3)He ventilation defect volume (VDV) and ventilation defect percent (VDP). RESULTS: Based on measurement variability, the smallest detectable difference (SDD) for (3)He VDV and VDP was determined to be 120 mL and 2%, respectively. Although no significant difference in spirometry or plethysmography was detected after 7 days, there was a significant difference in mean (3)He VDV (130 mL ± 250 mL, P < .0001) and VDP (3% ± 4%, P < .0001), although baseline and 7-day measurements were highly correlated (VDV: r = .85, P = .001; VDP: r = .94, P < .0001). We estimated the sample sizes required to detect a 5%/7%/10% change in (3)He VDP as 60/15/5 subjects per group. CONCLUSION: Hyperpolarized (3)He MRI VDP measurement precision resulted in an SDD for individual CF subjects of 2%, indicating that changes greater than this can be attributed to lung functional changes and not measurement error. After 7 days, significant changes in mean (3)He VDV and VDP were detected and these changes were not reflected by changes in pulmonary function measurements. These findings demonstrate the high sensitivity and reproducibility of (3)He MRI functional imaging that permits the use of relatively small samples sizes in CF interventional studies.