Influence of Aortic Arch Morphology on Renal Perfusion in Patients with Coarctation of the Aorta: An Exploratory Study.

Objectives: The configuration of the aortic arch, particularly a Gothic arch shape, in individuals with corrected coarctation of the aorta (CoA) has been associated with a decreased systolic wave amplitude across the arch, which could potentially impair renal perfusion and elevate the risk of arterial hypertension. This study aims to explore the relationship between the morphological characteristics of the aortic arch and their impact on renal perfusion in patients with CoA. Methods: Seventy-one subjects with corrected CoA underwent continuous 24 h ambulatory blood pressure monitoring, computed tomography to assess the aortic arch, and renal perfusion scanning. Subjects were stratified into three groups based on the height-to-width (H/W) ratio of their aortic arch: Group 1 with a H/W ratio of <0.65, Group 2 with a H/W ratio between 0.65 and 0.85, and Group 3 with a H/W ratio of >0.85. Results: Groups 1 and 2 (53,78% and 62.63%) presented with a higher hypertension prevalence of elevated blood pressure than Group 3 (38.89%). Notable variations were observed among the subjects in the time to peak perfusion (Tmax) in the left kidney across the groups. Group 1 showed a median Tmax at 0.27, Group 2 at 0.13, and Group 3 at -0.38 (p-value = 0.079). The differences in Tmax for the right kidney followed a similar trend but were not statistically significant (Group 1 at 0.61, Group 2 at 0.22, and Group 3 at 0.11; p-value = 0.229). Conclusions: This study suggests that variations in the aortic arch morphology might not significantly influence renal perfusion in CoA patients. This indicates the potential adaptability of the renal blood flow, which appears to compensate for reduced perfusion, thus minimizing adverse effects on the kidney function. This adaptability suggests an inherent physiological resilience, emphasizing the need for further targeted research to understand the specific interactions and impacts on treatment strategies for CoA.

Potential utility of B-type natriuretic peptides in secondary prevention following percutaneous coronary intervention in remote communities of Western Australia.

INTRODUCTION: A third of all acute coronary events that present in the Australian population occur in patients with established coronary heart disease. This study assessed the prognostic value of combined B-type natriuretic peptides (BNP) measurement and quantitative myocardial perfusion scan (MPS) data for cardiac events (CE). MATERIAL AND METHODS: This retrospective cohort study involved 133 patients from rural Western Australia. The cut-off for normality was 6.0 for qualitative summed difference scores (SDS) of MPS and 400 pg/mL for BNP. RESULTS: Patients with no CE had a mean SDS and BNP (1.52 with a 95% CI of 0.34 to 2.69), (175.9 with a 95% CI of 112.7-239.1) that was lower than patients with CE (6.54 with 95% CI 4.18-9.89) (P = 0.0003), (669.1 with 95% CI 543.9-794.3) (P < 0.0001). The sensitivity and specificity of combined testing for predicting CE respectively were 79.6% and 86.3% for SDS, 84.6% and 94.1% for BNP, and 100% and 92.7% for SDS and BNP combined. DISCUSSION AND CONCLUSION: Elevated BNP is marginally superior to MPS in predicting CEs in patients who have previously undergone percutaneous coronary intervention (PCI); however, MPS can identify the region of myocardium most at risk. Routine BNP monitoring in this subgroup may serve as secondary prevention by identifying subclinical disease.

Rural communities are disproportionately affected by preventable coronary heart disease-related deaths and access to cardiac imaging techniques can be infrequent or unavailable.Secondary prevention strategies can reduce hospital readmissions and contribute to improving the management of chronic conditions.This study demonstrated that elevated B-type natriuretic peptides levels were marginally superior to myocardial perfusion scans in predicting cardiac events in patients with prior percutaneous coronary intervention.Monitoring BNP levels in rural patients with prior percutaneous coronary interventions is a relatively non-invasive and inexpensive, and may lead to improved risk estimation, identify the subclinical disease and provoke further investigation as clinically appropriate.

NT-proBNP level as a substitute for myocardial perfusion scan in preoperative cardiovascular risk assessment in noncardiac surgery.

BACKGROUND: Preoperative cardiovascular risk assessment is one of the main principles before noncardiac surgeries. Cardiac stress imaging, such as myocardial perfusion scan (MPS), is a proposed cardiovascular risk evaluation method according to the latest guidelines. Yet, its efficacy, along with the cost-effectiveness of the method, has been questioned in previous studies. Our study aims to evaluate the utility of N-terminal pro-b-type natriuretic peptide (NT-proBNP) level measurement in predicting postoperative cardiovascular complications in candidates who have undergone an MPS before surgery and compare the results. METHODS: A cohort of 80 patients with a revised cardiac risk index score of one or more who were scheduled for moderate to high-risk noncardiac surgeries and met the criteria to undergo an MPS for risk assessment were included in the study. All of them underwent an MPS one week before surgery. Their preoperative NT-proBNP, troponin levels, and electrocardiograms were obtained one day before surgery and again on day three postoperative. The predictive efficacy of NT-proBNP levels and MPS were compared. RESULTS: Seventy-eight patients underwent surgery, three of which exhibited a rise in troponin level, six showed changes on electrocardiogram, and pulmonary edema was detected in one, three days after surgery. There was no mortality in our patients. The sensitivity and specificity of the MPS for predicting postoperative cardiovascular complications were 100% and 66%, respectively. MPS also had a positive predictive value of 20% and a negative predictive value of 100% in our study. A 332.5 pg/ml cut-off value for NT-proBNP level yielded a sensitivity of 100%, specificity of 79.2%, positive predictive value of 40%, and negative predictive value of 100%. CONCLUSIONS: Our study reveals the incremental specificity and positive predictive value of NT-proBNP level measurement in preoperative cardiovascular risk evaluation compared to MPS. Given the low feasibility, high costs, and disappointing predictive value of MPS, preoperative NT-proBNP level assessment can be substituted. This method can assist anesthesiologists and surgeons with precisely detecting at-risk patients resulting in taking proper measures to reduce the morbidity and mortality of the proposed patients before and during surgeries.

Imaging modalities for confirming pulmonary embolism during pregnancy: results from a multicenter international study.

OBJECTIVES: We explored the variations in use of imaging modalities for confirming pulmonary embolism (PE) according to the trimester of pregnancy. METHODS: We included all pregnant patients with confirmed acute PE from RIETE, a prospective registry of patients with PE (03/2001-02/2020). Imaging modalities included computed tomography pulmonary angiography (CTPA), ventilation-perfusion (V/Q) scan, or presence of signs of acute PE along with imaging-confirmed proximal deep vein thrombosis (pDVT) without pulmonary vascular imaging. We compared the imaging modalities to postpartum patients with PE, and other non-pregnant women with PE. RESULTS: There were 157 pregnant patients (age: 32.7 ± 0.5), 228 postpartum patients (age: 33.9 ± 0.5), and 23,937 non-pregnant non-postpartum women (age: 69.5 ± 0.1). CTPA was the most common modality for confirming PE, from 55.7% in first trimester to 58.3% in second trimester, and 70.0% in third trimester. From first trimester to third trimester, V/Q scanning was used in 21.3%, 16.7%, and 18.3% of cases, respectively. Confirmed pDVT along with the presence of signs/symptoms of PE was the confirmatory modality for PE in 21.3% of patients in first trimester, 19.4% in second trimester, and 6.7% in third trimester. The proportion of postpartum patients confirmed with CTPA (85.5%) was comparable to that of non-pregnant non-postpartum women (83.2%). From the first trimester of pregnancy to postpartum period, there was a linear increase in the proportion of patients with PE diagnosed with CTPA (p = 0.039). CONCLUSION: CTPA was the primary modality for confirming PE in all trimesters of pregnancy, although its proportional use was higher in later stages of pregnancy. KEY POINTS: • Computed tomography pulmonary angiography (CTPA) was the primary modality of diagnosis in all trimesters of pregnancy among patients with confirmed pulmonary embolism, even in the first trimester. • From the first trimester of pregnancy to postpartum period, there was a linear increase in the proportion of patients with pulmonary embolism who were diagnosed based on CTPA. • In the postpartum period, use of CTPA as the modality to confirm pulmonary embolism was comparable to non-pregnant patients.

Dual-Energy Computed Tomography Compared to Lung Perfusion Scintigraphy to Assess Pulmonary Perfusion in Patients Screened for Endoscopic Lung Volume Reduction.

BACKGROUND: Endoscopic lung volume reduction (ELVR) using one-way endobronchial valves is a technique to reduce hyperinflation in patients with severe emphysema by inducing collapse of a severely destroyed pulmonary lobe. Patient selection is mainly based on evaluation of emphysema severity on high-resolution computed tomography and evaluation of lung perfusion with perfusion scintigraphy. Dual-energy contrast-enhanced CT scans may be useful for perfusion assessment in emphysema but has not been compared against perfusion scintigraphy. AIMS: The aim of the study was to compare perfusion distribution assessed with dual-energy contrast-enhanced computed tomography and perfusion scintigraphy. MATERIAL AND METHODS: Forty consecutive patients with severe emphysema, who were screened for ELVR, were included. Perfusion was assessed with 99mTc perfusion scintigraphy and using the iodine map calculated from the dual-energy contrast-enhanced CT scans. Perfusion distribution was calculated as usually for the upper, middle, and lower thirds of both lungs with the planar technique and the iodine overlay. RESULTS: Perfusion distribution between the right and left lung showed good correlation (r = 0.8). The limits of agreement of the mean absolute difference in percentage perfusion per region of interest were 0.75-5.6%. The upper lobes showed more severe perfusion reduction than the lower lobes. Mean difference in measured pulmonary perfusion ranged from -2.8% to 2.3%. Lower limit of agreement ranged from -8.9% to 4.6% and upper limit was 3.3-10.0%. CONCLUSION: Quantification of perfusion distribution using planar 99mTc perfusion scintigraphy and iodine overlays calculated from dual-energy contrast-enhanced CTs correlates well with acceptable variability.

Use of Ventilation-Perfusion Single-Photon Emission Computed Tomography to Select the Target Lobe for Endobronchial Valve Lung Volume Reduction.

BACKGROUND: Quantitative planar ventilation-perfusion (VQ) has a complementary role in target lobe selection for endobronchial valve lung volume reduction (EBV-LVR), especially in homogenous disease. We investigated a novel method of lung lobar quantitation using VQ single-photon emission computed tomography (SPECT) with computed tomography (CT) to generate a parameter called the ventilation-perfusion differential index (VQDI). AIM: The aim of this study was to validate VQDI as a parameter for target lobe selection in EBV-LVR against the gold standard test of quantitative computed tomography (qCT). METHODS: This study was a prospective, multi-centre, single-blinded, observational study of EBV-LVR patients. Baseline and 3-month post intervention VQ SPECT and qCT were performed. The target lobe was chosen using qCT and planar VQ report (CTTL) whilst blinded to VQDI. Post EBV-LVR, our nuclear physician, blinded to CTTL, selected a target lobe using deidentified VQDI (VQDITL). Inter-rater agreement between CTTL and VQDITL was calculated by Kappa statistic. Treatment outcomes were analysed with a linear mixed-effects model. RESULTS: There was a high concordance between CTTL and VQDITL in 16 patients (89%, Kappa statistic = 0.85). Post EBV-LVR, our subjects showed significant changes in FEV1 (mean difference [MD] +150 mL, p < 0.001), target lobe volume reduction (MD -973 mL, p < 0.001), residual volume (MD -800 mL, p < 0.001), and St. George's Respiratory Questionnaire score (MD -11, p = 0.001). Improvements in 6-minute walk distances did not reach statistical significance. CONCLUSION: In this study of treatment responders, EBV-LVR target lobe selection using VQDI concurs with qCT and thus supports its value for this purpose. It complements qCT and may potentially be of synergistic value especially in homogenous emphysema.

Diagnostic imaging to investigate pulmonary embolism in pregnancy using CT-Pulmonary angiography versus perfusion scan.

BACKGROUND: Pulmonary embolism (PE) is one of the major causes of maternal mortality; however, its diagnosis based on clinical presentation is a significant challenge; therefore, imaging is required. This study aims to determine the nondiagnostic rate of PE in pregnant women who initially undergone computed tomographic pulmonary angiography (CTPA) or perfusion scan. MATERIALS AND METHODS: In this cross-sectional study, all pregnant or 6-week postpartum women with clinical suspicion of PE were evaluated and underwent CTPA or perfusion scan between March 2017 and June 2019. The nondiagnostic rate of each method was defined as the outcome of this study. RESULTS: One hundred and eighty-two women with a clinical suspicion of PE were included, among which the initial imaging method was CTPA in 122 (67.03%) and perfusion scan in 60 (32.97%) women. The nondiagnostic imaging for CTPA was significantly lower than the perfusion scan (9 cases (7.4%) versus 25 cases (41.7%), respectively). Logistic regression assessment revealed a statistical outcome by controlling the confounders including gestational trimester at diagnosis, hypertension, ejection fraction, and tachycardia (odds ratio 15.911, 95% confidence interval: 5.177-48.897, P < 0.001). CONCLUSION: Based on the current study, CTPA is superior to perfusion scans to diagnose PE among pregnant or postpartum women with normal chest X-ray suspicion for PE.

Incidence of residual perfusion defects by lung scintigraphy in patients treated with rivaroxaban compared with warfarin for acute pulmonary embolism.

Residual perfusion defects (RPD) as detected by lung scintigraphy occur in over 50% of patients with acute pulmonary embolism (PE) treated with vitamin K antagonists but there is lack of data in patients treated with direct oral anticoagulants. The aim of this retrospective study was to estimate the incidence of RPD detected by ventilation perfusion (VQ) scan at 3-6 months in patients with first acute symptomatic PE treated with rivaroxaban compared to warfarin. Consecutive eligible patients treated with rivaroxaban as part of a previous study were identified. The Monash Health Radiology database was used to identify a historical cohort of age matched (± 5 years) patients treated with warfarin. Follow-up VQ scans were classified as normal (no perfusion defect) or abnormal (matched or unmatched perfusion defects) by two independent nuclear medicine physicians blinded to treatment. Any disagreement was resolved by consensus. One hundred and ninety patients with PE (95 in each cohort) were included (mean age 56.8 years; 41.1% males; 54.2% unprovoked). In the overall cohort, 31.1% had RPD with a significantly lower incidence of RPD in rivaroxaban treated patients 23.2% (95% CI 15.8-32.6), compared to warfarin 38.9% (95% CI 29.8-49.0). Treatment with rivaroxaban was associated with a significantly lower incidence of RPD detected by VQ scan at 3-6 months compared to warfarin. This supports recent in-vitro data suggesting an indirect enhancement of fibrinolysis by direct oral Xa inhibitors but requires confirmation in larger studies.

Overutilisation of imaging studies for diagnosis of pulmonary embolism: are we following the guidelines?

OBJECTIVE: To evaluate if imaging studies such as CT pulmonary angiography (CTPA) or ventilation-perfusion (V/Q) scan are ordered according to the current guidelines for the diagnosis of pulmonary embolism (PE). METHODS: We performed a retrospective observational cohort study in all adult patients who presented to the Sparrow Hospital Emergency Department from January 2014 to December 2016 and underwent CTPA or V/Q scan. We calculated the Wells' score retrospectively, and d-dimer values were used to determine if the imaging study was justified. RESULTS: A total of 8449 patients underwent CTPA (93%) or V/Q scan (7%), among which 142 (1.7%) patients were diagnosed with PE. The Wells' criteria showed low probabilities for PE in 96 % and intermediate or high probabilities in 4 % of total patients. Modified Wells' criteria demonstrated PE unlikely in 99.6 % and PE likely in 0.4 % of total patients. D-dimer was obtained in only 37 % of patients who were unlikely to have a PE or had a low score on Wells' criteria. Despite a low or unlikely Wells' criteria score and normal d-dimer levels, 260 patients underwent imaging studies, and none were diagnosed with PE. CONCLUSION: More than 99 % of CTPA or V/Q scans were negative in our study. This suggests extraordinary overutilisation of the imaging methods. D-dimer, recommended in patients with low to moderate risk, was ordered in only one-third of patients. Much greater emphasis of current guidelines is needed to avoid inappropriate utilisation of resources without missing diagnosis of PE.

The time factor in the LDI (Laser Doppler Imaging) diagnosis of burns.

BACKGROUND AND OBJECTIVE: The not quite rare occurrence of inaccurate clinical diagnoses of burns in early post-burn days leads to an inappropriate conservative treatment strategy, or unnecessary surgery. LDI (Laser Doppler Imaging) objectively evaluates skin blood circulation, which correlates with the depth of the burn and the length of healing. The aim of this work was to suggest cutoff values for detecting burns without healing potential within 3 weeks, which should have undergone surgery. METHOD: The burned area's average blood perfusion of 148 burns was measured on 115 patients, using the Laser Doppler Imager PIM III. A total of 268 measurements were performed from the one to the ninth post-burn day (PBD). The perfusion values were compared to the healing time or histology in the case of the surgical treatment. Cutoff values indicating surgery were investigated in various post-burn days; the ROC analysis was used. RESULTS: This work suggest statistically significant increasing cutoff values for indication to surgery (P = 0.05). From the third to the fifth day 148.5 perfusion units (PU), from the sixth to the seventh day 186.0 PU, from the eighth to the ninth PBD 269.5 PU. The cutoff value is not possible to establish until the second day. CONCLUSION: LDI is a useful method for wound healing prediction and an indication of the necessity of surgery. We have demonstrated that the diagnosis of the healing capacity of LDI needs to take into account the factor of time.

Impact of COVID-19 on Ventilation-Perfusion (V/Q) Scans: A Comparative Analysis of Pre-COVID-19 Era V/Q Scans and Post-COVID-19 Era Perfusion Scans.

Introduction The COVID-19 pandemic has profoundly impacted medical practices, including nuclear medicine. To minimize aerosol transmission risks, lung perfusion scintigraphy was preferred over traditional ventilation-perfusion (V/Q) scintigraphy during the pandemic. This study compares lung perfusion scans performed during COVID-19 with V/Q scans from the pre-COVID era. After reviewing this study, the reader will learn about V/Q scintigraphy and lung perfusion. Methods This retrospective observational study, conducted from December 2018 to July 2021, involved 868 patients - 511 in the pre-COVID era and 357 in the post-COVID era - at a single tertiary care center. The pretest probability of pulmonary embolism (PE) was determined using Wells' criteria, and data including demographics, clinical findings, and diagnostic test results (V/Q or lung perfusion scintigraphy) were collected. Results A 30% decline in lung scans was observed during the pandemic. In the pre-COVID era, 68.3% of scans had low, 27.8% had intermediate, and 3.9% had high probability for PE. During the pandemic, perfusion-only scans showed 57.3% low, 32.9% indeterminate, and 9.8% high probability for PE. Among COVID-19-positive patients, 48.9% had intermediate, and 11.1% had high probability scans. The rise in indeterminate and high-probability scans during the pandemic is attributed to COVID-19-related lung changes and hypercoagulability. Conclusion The perfusion component of lung scans is typically sufficient for evaluating acute PE. Omitting the ventilation part of the V/Q scan had minimal impact, with only a 5.1% increase in indeterminate/non-diagnostic scans using perfusion-only modified Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II) criteria during the post-COVID-19 era, likely due to underlying lung parenchymal involvement in COVID-19 patients. Additionally, there was a 5.9% rise in high-probability scans, attributed to the hypercoagulability and vascular complications associated with COVID-19.

SPECT Ventilation/Perfusion Imaging for Acute Pulmonary Embolism: Meta-analysis of Diagnostic Test Accuracy.

RATIONALE AND OBJECTIVES: This study aimed to evaluate the diagnostic accuracies of ventilation/perfusion-single photon emission computed tomography (V/Q-SPECT) imaging modalities for acute pulmonary embolism (PE). These included, in addition to V/Q-SPECT, V/Q-SPECT with low-dose computed tomography (CT; V/Q-SPECT-CT), Q-SPECT with low-dose CT (Q-SPECT-CT), and Q-SPECT. MATERIALS AND METHODS: PubMed, Embase, CINAHL, and Web of Science databases were searched, and studies included if they studied ≥10 adult participants with acute PE and reported data on the imaging tests' diagnostic performance. Data were meta-analyzed using bivariate random effects regression model. RESULTS: Data from participants totaling 4146 from 11 V/Q-SPECT studies, 785 from 7 V/Q-SPECT-CT studies, 1196 from 7 Q-SPECT-CT studies, and 728 from five Q-SPECT studies were separately meta-analyzed. The bivariate weighted mean sensitivity and specificity were 0.94 (95% confidence interval [CI]: 0.88-0.97) and 0.95 (95% CI: 0.87-0.98) for V/Q-SPECT, 0.95 (95% CI: 0.88-0.98) and 0.99 (95% CI: 0.92-1.00) for V/Q-SPECT-CT, 0.92 (95% CI: 0.79-0.97) and 0.92 (95% CI: 0.83-0.96) for Q-SPECT-CT, and 0.89 (95% CI: 0.76-0.95) and 0.86 (95% CI: 0.67-0.95) for Q-SPECT studies. The positive and negative likelihood ratios (+LRs and -LRs) were 17.4 (6.9-44.0) and 0.06 (0.03-0.13), 76.7 (11.8-498.0) and 0.06 (0.02-0.13), 11.0 (5.3-22.9) and 0.09 (0.04-0.23), and 6.4 (2.6-15.8) and 0.13 (0.07-0.27) for V/Q-SPECT, V/Q-SPECT-CT, Q-SPECT-CT, and Q-SPECTs, respectively. CONCLUSION: In the diagnosis of acute PE, this meta-analysis showed that V/Q-SPECT-CT had the highest specificity and +LR. Conversely, Q-SPECT showed the lowest specificity and an unfavorably high -LR.

Exploring pregnant individuals' counseling needs regarding urgent imaging to rule out pulmonary embolism.

Background: Computed tomography pulmonary angiogram and lung scintigraphy with ventilation/perfusion scan are needed to diagnose pulmonary embolism (PE) in pregnancy. Their associated ionizing radiation doses are considered safe in pregnancy. A standardized patient information tool may improve patient counseling and reduce testing hesitancy. Objectives: In this context, we sought to address 1) what patients want to know before undergoing these tests and 2) how they want the information to be provided to them. Methods: We used a qualitative descriptive methodology. We recruited pregnant participants at the McGill University Health Center in Montreal, Canada. Structured interviews explored information needs about PE and diagnostic imaging for PE. The interview transcripts' themes were analyzed with a hybrid deductive and inductive approach. Results: Of 21 individuals approached, 20 consented to participate. Four had been previously investigated for PE. Participants requested information about the risks associated with PE and radiation and their effects on maternal and fetal health. They preferred for radiation doses to be presented in comparison with known radiation thresholds for fetal harm. They suggested that a written tool should be developed using an accessible language. Participants also indicated that the tool would be integrated into their decision-making process, emphasizing a lower risk tolerance for their fetus than for themselves. Conclusion: This single-center group of pregnant patients wished to be informed about the risks of PE and radiation associated with imaging. A written tool could help put information into context and facilitate decision making. These new insights may be used to inform counseling.

Optimizing emergency department imaging utilization for pulmonary emboli: A study on the effects of IV contrast rationing.

PURPOSE: To study the impact of a contrast mitigation protocol on imaging utilization for pulmonary embolism (PE) in the emergency department (ED). MATERIAL AND METHODS: Medical records of ED patients with suspected PE who underwent CT pulmonary angiography (CTPA) or ventilation-perfusion (VQ) scans were analyzed in control (3/15/22-4/15/22) and test (5/15/22-6/15/22) periods. The test period included a contrast mitigation protocol due to a global iodinated contrast shortage (05/2022-06/2022). Out of 610 scans, 28 were excluded for non-PE indications. Patient demographics, time metrics, and imaging reports were recorded. RESULTS: Among 11,019 ED visits, there were 582 imaging events for suspected PE. The test period exhibited a significantly lower imaging rate of 4.16 % compared to 6.54 % in the control period (p < 0.001). CTPA usage decreased by 47.73 %, while VQ scan usage increased by 775.00 % during the test period. Test period positivity rate was 0.82 %, with CTPA at 0.58 % (1/173) and VQ scan at 1.43 % (1/70). In the control period, the positivity rate was 0.29 %, with CTPA at 0.30 % (1/331) and VQ scan at 0.00 % (0/8). Previous hospitalization history was significantly higher in the test period (70/243 vs. 39/339, p < 0.001). The positivity rates between the two periods showed no significant difference (p = 0.57). There were no significant differences in ED length of stay and image acquisition times. CONCLUSION: The contrast mitigation protocol reduced CTPA use, increased VQ scans, and maintained positivity rates and image acquisition times. However, concerns persist about unnecessary imaging and low positivity rates, necessitating further research to optimize PE diagnostic algorithms.

Quantitative Computed Tomography and Response to Pronation in COVID-19 ARDS.

BACKGROUND: The use of prone position (PP) has been widespread during the COVID-19 pandemic. Whereas it has demonstrated benefits, including improved oxygenation and lung aeration, the factors influencing the response in terms of gas exchange to PP remain unclear. In particular, the association between baseline quantitative computed tomography (CT) scan results and gas exchange response to PP in invasively ventilated subjects with COVID-19 ARDS is unknown. The present study aimed to compare baseline quantitative CT results between subjects responding to PP in terms of oxygenation or CO2 clearance and those who did not. METHODS: This was a single-center, retrospective observational study including critically ill, invasively ventilated subjects with COVID-19-related ARDS admitted to the ICUs of Niguarda Hospital between March 2020-November 2021. Blood gas samples were collected before and after PP. Subjects in whom the PaO2 /FIO2 increase was ≥ 20 mm Hg after PP were defined as oxygen responders. CO2 responders were defined when the ventilatory ratio (VR) decreased during PP. Automated quantitative CT analyses were performed to obtain tissue mass and density of the lungs. RESULTS: One hundred twenty-five subjects were enrolled, of which 116 (93%) were O2 responders and 51 (41%) CO2 responders. No difference in quantitative CT characteristics and oxygen were observed between responders and non-responders (tissue mass 1,532 ± 396 g vs 1,654 ± 304 g, P = .28; density -544 ± 109 HU vs -562 ± 58 HU P = .42). Similar findings were observed when dividing the population according to CO2 response (tissue mass 1,551 ± 412 g vs 1,534 ± 377 g, P = .89; density -545 ± 123 HU vs -546 ± 94 HU, P = .99). CONCLUSIONS: Most subjects with COVID-19-related ARDS improved their oxygenation at the first pronation cycle. The study suggests that baseline quantitative CT scan data were not associated with the response to PP in oxygenation or CO2 in mechanically ventilated subjects with COVID-19-related ARDS.

Lessons in clinical reasoning - pitfalls, myths, and pearls: a case of crushing, substernal chest pain.

OBJECTIVES: Diagnostic error is not uncommon and diagnostic accuracy can be improved with the use of problem representation, pre-test probability, and Bayesian analysis for improved clinical reasoning. CASE PRESENTATION: A 48-year-old female presented as a transfer from another Emergency Department (ED) to our ED with crushing, substernal pain associated with dyspnea, diaphoresis, nausea, and a tingling sensation down both arms with radiation to the back and neck. Troponins were elevated along with an abnormal electrocardiogram. A negative myocardial perfusion scan led to the patient's discharge. The patient presented to the ED 10 days later with an anterior ST-elevation myocardial infarction. CONCLUSIONS: An overemphasis on a single testing modality led to diagnostic error and a severe event. The use of pre-test probabilities guided by history-taking can lead to improved interpretation of test results, ultimately improving diagnostic accuracy and preventing serious medical errors.

Case report: Steroid-responsive acute chorea as first presentation of the coexistence of Moyamoya and Graves' disease.

Background: Chorea is a movement disorder characterized by abrupt, rapid, and uncontrollable, random movements from one part of the body to another with motor impersistence. Sporadic chorea is rarely caused by either thyrotoxicosis or Moyamoya disease (MMD). Methods and results: In this case report, we describe a female patient with chorea with the rare coexistence of Graves' disease and Moyamoya disease. Tc-99m ethyl cysteinate dimer (ECD) brain perfusion single-photon emission computed tomography (SPECT) showed mild to moderate hypoperfusion in bilateral frontal and left temporal regions. After administering dexamethasone 20 mg for 5 days, her choreic movement symptoms recovered rapidly. Conclusion: Although uncommon, thyrotoxicosis and Moyamoya disease can co-occur, especially in Asian female adults. Excessive thyroid hormones contribute to the dysregulation of neurotransmitters in basal ganglia-thalamocortical circuits. Moyamoya disease is responsible for ischemic changes affecting the excitatory-inhibitory circuits between the basal ganglia and the neocortex. Under a state of coexistence, thyrotoxicosis exaggerates cerebral metabolism, aggravating the impaired cerebral perfusion induced by Moyamoya disease. Moreover, inflammatory reactions caused by thyroid autoantibodies may also promote the progression of Moyamoya disease. In our experience, treatment with steroids may not only synergize the anti-thyroid effect but may also be a way to modulate the neurotransmitters within the basal ganglia or restore cerebral perfusion. We suggest that evaluation of the thyroid function status in Moyamoya disease is essential.

Non Target Shunting of Tc-99m Macroaggregates of Albumin and Radiolabeled Yttrium-90 Microspheres into Hepatic Falciform Artery - Less Observed Arterial Variant not to be Overlooked.

Identification of nontarget arteries is crucial prior to Yttrium-90 microspheres radioembolization. We present a case where an uncommon nontarget artery, the hepatic falciform artery was identified during work up for radioembolization and necessary preventive measures were taken to minimize the complications.

Risk stratification of diabetic patients with unusual cardiac symptoms using a myocardial perfusion scan.

BACKGROUND: Autonomic nervous system dysfunction in diabetic patients can result in an atypical presentation of cardiovascular disease that can be missed. We aimed to use single-photon emission computed tomography (SPECT) to assess cardiovascular disease (CAD) in diabetic patients with atypical pain to determine whether the pain above reflects the CAD. METHOD: Diabetic patients with atypical cardiac symptoms were referred to the SPECT department. Demographic data such as age, gender, diabetes status, and other underlying diseases were gathered. A myocardial perfusion scan was then performed. The results were recorded to evaluate the risk of myocardial ischemia and the degree of coronary artery involvement in a non-invasive manner. RESULTS: The study included 222 (177 female) subjects with mean ages of 63.01±11.62 and 59.41±9.19 in positive and negative SPECT, respectively. The most common symptoms were atypical chest pain (51.8%), followed by shortness of breath (50.5%), nausea, and syncope (0.9%). Cardiac parameters, such as the summed stress score (SSS), summed rest score (SRS), total perfusion deficit in stress (TPD-s), total perfusion deficit in rest (TPD-r), were significantly higher in the group with coronary artery involvement (P<0.001). However, ejection fraction (EF), end-diastolic volume (EDV), and end-systolic volumes (ESV) parameters were not (P=.0.328, 0.351, and 0.443, respectively). CONCLUSIONS: The mere presence of diabetes does not necessitate any additional diagnostic tests beyond those required for the general population, and it is possible to follow a diagnostic course similar to that of the general population.