Current Applications of Artificial Intelligence in Sarcoidosis.

PURPOSE: Sarcoidosis is a complex disease which can affect nearly every organ system with manifestations ranging from asymptomatic imaging findings to sudden cardiac death. As such, diagnosis and prognostication are topics of continued investigation. Recent technological advancements have introduced multiple modalities of artificial intelligence (AI) to the study of sarcoidosis. Machine learning, deep learning, and radiomics have predominantly been used to study sarcoidosis. METHODS: Articles were collected by searching online databases using keywords such as sarcoid, machine learning, artificial intelligence, radiomics, and deep learning. Article titles and abstracts were reviewed for relevance by a single reviewer. Articles written in languages other than English were excluded. CONCLUSIONS: Machine learning may be used to help diagnose pulmonary sarcoidosis and prognosticate in cardiac sarcoidosis. Deep learning is most comprehensively studied for diagnosis of pulmonary sarcoidosis and has less frequently been applied to prognostication in cardiac sarcoidosis. Radiomics has primarily been used to differentiate sarcoidosis from malignancy. To date, the use of AI in sarcoidosis is limited by the rarity of this disease, leading to small, suboptimal training sets. Nevertheless, there are applications of AI that have been used to study other systemic diseases, which may be adapted for use in sarcoidosis. These applications include discovery of new disease phenotypes, discovery of biomarkers of disease onset and activity, and treatment optimization.

Artificial Intelligence for Interstitial Lung Disease Analysis on Chest Computed Tomography: A Systematic Review.

RATIONALE AND OBJECTIVES: High-resolution computed tomography (HRCT) is paramount in the assessment of interstitial lung disease (ILD). Yet, HRCT interpretation of ILDs may be hampered by inter- and intra-observer variability. Recently, artificial intelligence (AI) has revolutionized medical image analysis. This technology has the potential to advance patient care in ILD. We aimed to systematically evaluate the application of AI for the analysis of ILD in HRCT. MATERIALS AND METHODS: We searched MEDLINE/PubMed databases for original publications of deep learning for ILD analysis on chest CT. The search included studies published up to March 1, 2021. The risk of bias evaluation included tailored Quality Assessment of Diagnostic Accuracy Studies and the modified Joanna Briggs Institute Critical Appraisal checklist. RESULTS: Data was extracted from 19 retrospective studies. Deep learning techniques included detection, segmentation, and classification of ILD on HRCT. Most studies focused on the classification of ILD into different morphological patterns. Accuracies of 78%-91% were achieved. Two studies demonstrated near-expert performance for the diagnosis of idiopathic pulmonary fibrosis (IPF). The Quality Assessment of Diagnostic Accuracy Studies tool identified a high risk of bias in 15/19 (78.9%) of the studies. CONCLUSION: AI has the potential to contribute to the radiologic diagnosis and classification of ILD. However, the accuracy performance is still not satisfactory, and research is limited by a small number of retrospective studies. Hence, the existing published data may not be sufficiently reliable. Only well-designed prospective controlled studies can accurately assess the value of existing AI tools for ILD evaluation.

Utility of electrophysiologic testing for sudden death risk stratification in cardiac sarcoidosis patients with mildly impaired left ventricular function.

BACKGROUND: Ventricular arrhythmias (VA) account for at least 25% of deaths caused by cardiac sarcoidosis (CS) and may arise in patients with mildly impaired LVEF (>35%). OBJECTIVE: In the current study, we examine whether EP study may be used for sudden death risk stratification in CS patients who have mildly impaired LVEF and a diagnosis of highly probable or probable CS according to the World Association of Sarcoidosis and Other Granulomatous Diseases Sarcoidosis Organ Assessment Instrument (WASOGI). METHODS: All patients: (1) exhibited a diagnosis of highly probable or probable CS according to the WASOGI, (2) exhibited cardiac MRI findings consistent with CS, (3) exhibited LVEF >45% and (4) underwent EP study. Device interrogations, transmissions and medical records were reviewed for all patients. RESULTS: We identified 46 CS patients with mildly impaired LVEF. VA were induced in 11 patients and 10/11 patients underwent ICD placement. Thirty-five patients had no VA and 24/35 patients underwent placement of an ILR. During the follow-up period, the VA event rate was 6.5%. The negative and positive predictive values of the EP study for the development of VA were 100% and 27.2%, respectively. CONCLUSIONS: In CS patients with mildly impaired LVEF and a diagnosis of highly probable or probable CS, a negative EP study was highly predictive of the absence of VA. The successful execution of future prospective studies is contingent upon enrollment of phenotypically homogenous cardiac sarcoidosis patients.

Moderate or Severe Impairment in Pulmonary Function is Associated with Mortality in Sarcoidosis Patients Infected with SARS­CoV­2.

PURPOSE: To investigate whether sarcoidosis patients infected with SARS-CoV-2 are at risk for adverse disease outcomes. STUDY DESIGN AND METHODS: This retrospective study was conducted in five hospitals within the Mount Sinai Health System during March 1, 2020 to July 29, 2020. All patients diagnosed with COVID-19 were included in the study. We identified sarcoidosis patients who met diagnostic criteria for sarcoidosis according to accepted guidelines. An adverse disease outcome was defined as the presence of intubation and mechanical ventilation or in-hospital mortality. In sarcoidosis patients, we reported (when available) the results of pulmonary function testing measured within 3 years prior to the time of SARS­CoV­2 infection. A multivariable logistic regression model was used to generate an adjusted odds ratio (aOR) to evaluate sarcoidosis as a risk factor for an adverse outcome. The same model was used to analyze sarcoidosis patients with moderate and/or severe impairment in pulmonary function. RESULTS: The study included 7337 patients, 37 of whom (0.5%) had sarcoidosis. The crude rate of developing an adverse outcome was significantly higher in patients with moderately and/or severely impaired pulmonary function (9/14 vs. 3/23, p = 0.003). While the diagnosis of sarcoidosis was not independently associated with risk of an adverse event, (aOR 1.8, 95% CI 0.9-3.6), the diagnosis of sarcoidosis in patients with moderately and/or severely impaired pulmonary function was associated with an adverse outcome (aOR 7.8, 95% CI 2.4-25.8). CONCLUSION: Moderate or severe impairment in pulmonary function is associated with mortality in sarcoidosis patients infected with SARS­CoV­2.

Diagnosis and Detection of Sarcoidosis. An Official American Thoracic Society Clinical Practice Guideline.

Background: The diagnosis of sarcoidosis is not standardized but is based on three major criteria: a compatible clinical presentation, finding nonnecrotizing granulomatous inflammation in one or more tissue samples, and the exclusion of alternative causes of granulomatous disease. There are no universally accepted measures to determine if each diagnostic criterion has been satisfied; therefore, the diagnosis of sarcoidosis is never fully secure.Methods: Systematic reviews and, when appropriate, meta-analyses were performed to summarize the best available evidence. The evidence was appraised using the Grading of Recommendations, Assessment, Development, and Evaluation approach and then discussed by a multidisciplinary panel. Recommendations for or against various diagnostic tests were formulated and graded after the expert panel weighed desirable and undesirable consequences, certainty of estimates, feasibility, and acceptability.Results: The clinical presentation, histopathology, and exclusion of alternative diagnoses were summarized. On the basis of the available evidence, the expert committee made 1 strong recommendation for baseline serum calcium testing, 13 conditional recommendations, and 1 best practice statement. All evidence was very low quality.Conclusions: The panel used systematic reviews of the evidence to inform clinical recommendations in favor of or against various diagnostic tests in patients with suspected or known sarcoidosis. The evidence and recommendations should be revisited as new evidence becomes available.

Diagnosis and detection of sarcoidosis: an official American Thoracic Society Clinical Practice Guideline

The diagnosis of sarcoidosis is not standardized but is based on three major criteria: a compatible clinical presentation, finding nonnecrotizing granulomatous inflammation in one or more tissue samples, and the exclusion of alternative causes of granulomatous disease. There are no universally accepted measures to determine if each diagnostic criterion has been satisfied; therefore, the diagnosis of sarcoidosis is never fully secure. Systematic reviews and, when appropriate, meta-analyses were performed to summarize the best available evidence. The evidence was appraised using the Grading of Recommendations, Assessment, Development, and Evaluation approach and then discussed by a multidisciplinary panel. Recommendations for or against various diagnostic tests were formulated and graded after the expert panel weighed desirable and undesirable consequences, certainty of estimates, feasibility, and acceptability. The clinical presentation, histopathology, and exclusion of alternative diagnoses were summarized. On the basis of the available evidence, the expert committee made 1 strong recommendation for baseline serum calcium testing, 13 conditional recommendations, and best practice statement. All evidence was very low quality.The panel used systematic reviews of the evidence to inform clinical recommendations in favor of or against various diagnostic tests in patients with suspected or known sarcoidosis. The evidence and recommendations should be revisited as new evidence becomes available.

Catheter ablation of atrial arrhythmias in cardiac sarcoidosis.

BACKGROUND: We previously reported on the incidence and clinical implications of supraventricular arrhythmia in patients with cardiac sarcoidosis (CS). The role of catheter ablation for the management of atrial arrhythmia (AA) in this patient population is unknown. METHODS AND RESULTS: One hundred consecutive patients with CS were monitored for the incidence of supraventricular arrhythmias. Those with persistent symptoms despite optimal medical therapy proceeded to catheter ablation. Following ablation, all patients were followed serially with Holter monitoring or device interrogation. Thirty-two (32%) patients had symptomatic supraventricular arrhythmias. Nine (28%) patients had symptomatic AA requiring catheter ablation for clinical indications. Mean age was 55 ± 11.6 years. Five (56%) patients had atrial fibrillation (AF), of whom 2 also had cavotricuspid isthmus ablation. Four patients had isolated atrial flutter: 2 patients with left atrial flutter, and 2 patients with cavotricuspid flutter. All other arrhythmias were ablated in the left atrium. Mean duration of follow-up was 1.8 ± 1.9 years. One patient with atypical atrial flutter, and one patient with AF have had recurrence; the remaining patients remain in sinus rhythm. CONCLUSIONS: Our study suggests that AA in CS is frequently left atrial in origin. Catheter ablation appears to be effective and safe for the maintenance of sinus rhythm in patients with CS.

The WASOG Sarcoidosis Organ Assessment Instrument: An update of a previous clinical tool.

INTRODUCTION: A Case Control Etiology of Sarcoidosis Study (ACCESS) sarcoidosis organ assessment instrument has been used for more than a decade to establish uniform standards for the probability of sarcoidosis organ involvement. The ACCESS instrument has become increasingly outdated as new technologies have been developed. Furthermore, the ACCESS instrument failed to address all possible organs involved with sarcoidosis. For these reasons, the World Association of Sarcoidosis and Other Granulomatous Diseases (WASOG) developed a new sarcoidosis organ assessment instrument. METHODS: Clinical sarcoidosis experts assessed various clinical manifestations for the probability of sarcoidosis organ involvement. Two criteria were required to apply this assessment: 1) histologic evidence of granulomatous inflammation of unknown cause in an organ that was not being assessed; 2) the clinical manifestation being addressed required that alternative causes other than sarcoidosis had been reasonably excluded. Clinical manifestations were assessed as either: a) highly probable: likelihood of sarcoidosis causing this manifestation of at least 90%.; b) probable: likelihood of sarcoidosis causing this manifestation of between 50 and 90%; c) possible: likelihood of sarcoidosis causing this manifestation of less than 50%. The sarcoidosis experts voted on the likelihood of sarcoidosis causing each manifestation using Delphi study methodology where at least 70% agreement of the experts was needed for consensus. RESULTS: Various clinical manifestations were classified as highly probable, at least probable, possible, or indeterminate when no consensus could be reached. CONCLUSION: An instrument was developed by expert opinion that may be useful for the clinician and researcher in establishing criteria for sarcoidosis organ involvement.

Sarcoidosis of the upper and lower airways.

Sarcoidosis is a systemic granulomatous disease of undetermined etiology characterized by a variable clinical presentation and disease course. Although clinical granulomatous inflammation may occur within any organ system, more than 90% of sarcoidosis patients have lung disease. Sarcoidosis is considered an interstitial lung disease that is frequently characterized by restrictive physiologic dysfunction on pulmonary function tests. However, sarcoidosis also involves the airways (large and small), causing obstructive airways disease. It is one of a few interstitial lung diseases that affects the entire length of the respiratory tract - from the nose to the terminal bronchioles - and causes a broad spectrum of airways dysfunction. This article examines airway dysfunction in sarcoidosis. The anatomical structure of the airways is the organizational framework for our discussion. We discuss sarcoidosis involving the nose, sinuses, nasal passages, larynx, trachea, bronchi and small airways. Common complications of airways disease, such as, atelectasis, fibrosis, bullous leions, bronchiectasis, cavitary lesions and mycetomas, are also reviewed.

Recent advances in sarcoidosis.

Sarcoidosis, a systemic granulomatous disease of undetermined etiology, is characterized by a variable clinical presentation and course. During the past decade, advances have been made in the study of sarcoidosis. The multicenter ACCESS (A Case Control Etiologic Study of Sarcoidosis) trial recruited > 700 subjects with newly diagnosed sarcoidosis and matched control subjects. Investigators were unable to identify a single cause of sarcoidosis, but ACCESS paved the way for subsequent etiologic studies. The Mycobacterium tuberculosis catalase-peroxidase protein has been identified as a potential sarcoidosis antigen. Genetic aspects of the disease have been elucidated further. Genome-wide scans have identified candidate genes. Gene expression analyses have defined cytokine dysregulation in sarcoidosis more clearly. Although the criteria for diagnosis have not changed, sarcoidosis remains a diagnosis of exclusion best supported by a tissue biopsy specimen that demonstrates noncaseating granulomas in a patient with compatible clinical and radiologic features of the disease. Endobronchial ultrasound-guided transbronchial needle aspiration of mediastinal lymph nodes has facilitated diagnosis, often eliminating the need for more invasive procedures, such as mediastinoscopy. PET scanning has proven valuable in locating occult sites of active disease. Currently, no reliable prognostic biomarkers have been identified. The tumor necrosis factor inhibitors, a relatively new class of agents, have been used in patients with refractory disease. It is unclear whether phosphodiesterase-5 inhibitors, prostaglandin analogs, or endothelin antagonists should be used for the treatment of sarcoidosis-associated pulmonary hypertension.

Spectrum of fibrosing diffuse parenchymal lung disease.

The interstitial lung diseases are a heterogeneous group of disorders characterized by inflammation and/or fibrosis of the pulmonary interstitium. In 2002, the American Thoracic Society and the European Respiratory Society revised the classification of interstitial lung diseases and introduced the term diffuse parenchymal lung disease. The idiopathic interstitial pneumonias are a subtype of diffuse parenchymal lung disease. The idiopathic interstitial pneumonias are subdivided into usual interstitial pneumonia (with its clinical counterpart idiopathic interstitial pneumonia), nonspecific interstitial pneumonia, cryptogenic organizing pneumonia, acute interstitial pneumonia, desquamative interstitial pneumonia, respiratory bronchiolitis interstitial lung disease, and lymphocytic pneumonia. Sarcoidosis and hypersensitivity pneumonitis are the 2 most common granulomatous diffuse parenchymal lung diseases. Rheumatoid arthritis, systemic sclerosis, and dermatomyositis/polymyositis (causing antisynthetase syndrome) are diffuse parenchymal lung diseases of known association because these conditions are associated with connective tissue disease. Hermansky-Pudlak syndrome is a rare genetic diffuse parenchymal lung disease characterized by the clinical triad of pulmonary disease, oculocutaneous albinism, and bleeding diathesis. This review provides an overview of the chronic fibrosing diffuse parenchymal lung diseases. Its primary objective is to illuminate the clinical challenges encountered by clinicians who manage the diffuse parenchymal lung diseases regularly and to offer potential solutions to those challenges. Treatment for the diffuse parenchymal lung diseases is limited, and for many patients with end-stage disease, lung transplantation remains the best option. Although much has been learned about the diffuse parenchymal lung diseases during the past decade, research in these diseases is urgently needed.

"End-stage" pulmonary fibrosis in sarcoidosis.

Pulmonary fibrosis is an unusual "end stage" in patients with sarcoidosis. Fibrosis occurs in a minority of patients, and presents with a unique physiologic combination of airways dysfunction (obstruction) superimposed on the more common restrictive dysfunction. Imagin techniques are essential to the diagnosis, assessment and treatment of pulmonary fibrosis. Standard chest radiographs and CT scans may reveal streaks, bullae, cephalad retraction of the hilar areas, deviation of the trachea and tented diaphragm. Positive gallium and PET scans indicate residual reversible granulomatous disease and are important guides to therapy decisions. Treatment, usually with corticosteroids, is effective in those patients with positive scans, but fibrosis does not improve with any treatment. With severe functional impariment and patient disability, pulmonary hypertension and right heart failure may supervene for which the patient will require treatment. Oxygen, careful diuresis, sildenafil and bosentan may be salutary. These patients are candidates for lung transplantation.