59. Top Consults: Lung Transplant 101

We’re back with our Top Consults series to talk about Lung Transplant! This is a topic that every pulmonologist should have background knowledge about since it impacts the care of patients with end-stage lung disease of any cause. We will talk about the indications for referral and transplant, how to advise patients and some unique considerations for evaluation. Enjoy, rate and review us, and share your thoughts about the episode!

Meet Our Guests

Dr. Meghan Aversa is an Assistant Professor of Medicine at the University of Toronto and her expertise involves patients with end stage lung disease and lung transplant.

Dr. Hannah Mannem is an Associate Professor of Medicine at the University of Virginia Health. Hannah joined faculty at UVA in 2016 and she has expertise in ILD and Lung Transplant.

Learning Points

Trends in lung transplant:

  1. Global Increase in Lung Transplants: Over the past three decades, there has been a gradual worldwide increase in lung transplants, with approximately 4,500 performed annually. North America conducts over half of these transplants, and the growth is particularly notable in double lung transplants.
  2. Indications and Disease Trends: Interstitial lung disease (ILD) has seen a significant rise in lung transplant indications, surpassing COPD as the leading cause. ILD, especially idiopathic pulmonary fibrosis (IPF), constitutes a substantial portion (40%) of all transplants. However, the trend is primarily observed in North America.
  3. Decline in Cystic Fibrosis Cases: While Cystic Fibrosis is still a significant indication for lung transplant, its percentage has been declining, likely due to improvements in drugs and CFTR modulators.
  4. Evolution of Lung Transplant Candidates: Over the past five years, lung transplant candidates have become sicker, with higher listing scores and increased hospitalization rates at the time of transplant. More patients have antibodies affecting match difficulty. The average age of patients has increased, with 35% being over 65, a demographic that was previously considered contraindicated.
  5. Impact of COVID-19: The COVID-19 pandemic has influenced lung transplant trends. In 2020, UNOS added COVID-19-related ARDS and pulmonary fibrosis as indications. In 2021, these indications constituted about 10% of lung transplants, making it the third most common indication. Two-thirds were due to COVID-19 ARDS, and one-third due to pulmonary fibrosis. The long-term impact, especially with evolving vaccine dynamics, is still uncertain.

Indications for transplant referral:

  1. ISHLT Consensus Document Update (2021): The ISHLT consensus document for lung transplant candidate selection was updated in 2021. It is available on the ISHLT website and serves as a valuable guideline for pulmonologists considering referrals for lung transplant assessment.
  2. General Rule of Thumb for Chronic Lung Diseases: According to the consensus document, a general rule of thumb for all patients with chronic and stage lung diseases is to consider lung transplant if there is a high (more than 50%) risk of death from the lung disease within the next two years. Prognostic markers vary based on the underlying lung disease.
  3. Disease-Specific Recommendations: The consensus document provides disease-specific recommendations. The key diseases highlighted are COPD, ILD, CF, and PH.
    • COPD: Referral is recommended when the BODE index is in the range of 5 to 6, with additional factors that increase mortality, such as frequent exacerbations, low FEV1 (20-25%), or rapidly increasing BODE. Referral is also advised for clinically deteriorating patients or those with an unacceptably low quality of life despite maximal medical therapy.
    • ILD (Particularly IPF): Early referral is suggested, ideally at the time of diagnosis. For any pulmonary fibrosis, referral is recommended if FEC is less than 80% or declining by 10% in two years, or DLCO is less than 40% or declining by 15% in two years. Other factors for referral include radiographic progression or a need for supplemental oxygen.
    • Cystic Fibrosis (CF): Referral is encouraged for those with FEV1 less than 30%, and even 40% if there’s reduced walk distance, hypercapnia, PH, frequent exacerbations, or rapid decline.
    • Pulmonary Hypertension (PH): Referral criteria include a REVEAL score of eight, significant RV dysfunction, progressive disease on therapy, need for IV prostacyclin therapy, and specific conditions like PVOD, PCH, scleroderma pulmonary artery aneurysms, which should be referred early due to their rapid progression.

Transplant evaluation process

  1. Phases of Lung Transplant Evaluation:
    • Referral and Initial Visit: The process begins with a referral, often from a primary pulmonologist. Patients can also self-refer. The initial phase involves insurance authorization and confirming the underlying diagnosis while ensuring all other treatment options are exhausted.
    • Assessment of Disease Severity: The severity of end-stage lung disease is assessed to determine the timing of the workup, which varies depending on the patient’s condition and the center’s protocols.
    • Diagnostic Steps: A thorough diagnostic workup follows the initial visit, including various tests, imaging, and meetings with multidisciplinary teams to assess medical and social factors influencing transplant success.
    • Follow-Up Appointments: Patients typically have multiple follow-up appointments to track the evolution of the disease and ensure health maintenance and vaccinations are up to date.
    • Selection Committee: The final phase involves a selection committee that determines if the patient is a candidate. If so, there may be conditional requirements before officially listing the patient.
  2. Multidisciplinary Approach: Lung transplant evaluation involves collaboration with various specialists, including social work, finance, nutrition, pharmacy, physical therapy, and potentially other consult services. The efficiency of this process is optimized for both the patient and the medical team.
  3. Diagnostic Workup:
    • Medical Testing: Involves blood work, cardiac testing (echo, left and right heart cath), and imaging, including abdominal imaging, VQ scans, DEXA scans, and 24-hour urine analysis.
    • Multidisciplinary Meetings: Patients meet with members of the multidisciplinary team, addressing medical comorbidities as well as social and psychological factors.
    • Follow-Up Appointments: Multiple appointments allow for tracking disease progression and ensuring overall health maintenance.
  4. Selection Committee Decision: The patient receives a decision from the selection committee, determining candidacy. Sometimes, patients are considered candidates with conditions (e.g., completing vaccinations or losing weight). Timing of listing is also discussed to ensure optimal candidacy.
  5. Patient Involvement: Patients play an active role, and the process may involve self-referral, understanding and completing requirements, and active participation in follow-up appointments.
  6. Efficiency and Individualization: The evaluation process is tailored to the patient’s condition, and centers aim to efficiently organize diagnostic workup and multidisciplinary meetings to optimize patient care.

Timing of transplant listing for candidates

  • COPD Patients: For COPD patients, listing is likely when the Bode index is around 7, the FEV1 is under 20%, there is at least moderate pulmonary hypertension (PH), chronic hypercapnia, or severe exacerbations.
  • ILD Patients: Patients with interstitial lung disease (ILD) are likely to be listed when showing signs of progression or decline in forced expiratory capacity (FEC), diffusing capacity of the lungs for carbon monoxide (DLCO), or six-minute walk distance. Other indicators include hypoxemia, secondary pulmonary hypertension, or hospitalization for complications.
  • CF Patients: Cystic fibrosis (CF) patients are considered for listing when FEV1 is below 25% or is rapidly declining, and if they experience frequent hospitalizations. Listing criteria also include the presence of pulmonary hypertension, chronic hypoxemia, or hypercapnia.
  • Pulmonary Hypertension Patients: Those with primary pulmonary hypertension may be listed when the reveal score is above 10 on intravenous therapy, there is progressive hypoxemia, or if there are renal or liver dysfunctions associated with pulmonary hypertension (PH).

Changes from the LAS system to the CAS system

  1. Transition to Composite Allocation Score (CAS):
    • Background and Timing: In March 2023, the lung allocation system (LAS) transitioned to the composite allocation score (CAS), a major change in the allocation of lung transplants.
    • Reasoning Behind the Change: The change aimed to improve organ matching, prioritize sick candidates, enhance long-term survival, promote equity, increase transplant opportunities for specific patient groups (especially pediatric patients), and manage geographical variation in organ placement.
    • Components of CAS:
      • Medical Urgency: Based on waitlist mortality at one year without a transplant and the likelihood of survival post-transplant, now assessed at greater than five years, with equal weighting.
      • Recipient Variables: Includes factors like height discrepancy, blood type matching, sensitization (immune system matching), and other recipient variations.
      • Candidate Biology: Focuses on pediatric patients (less than 18 years old) and individuals are a prior living donor.
      • Donor Variables: Addresses donor characteristics, emphasizing proximity and travel distance from the organ hospital.
    • Early Data and Observations: The initial three-month monitoring period has shown changes in O blood type scores, prompting adjustments. Notable outcomes include a 16% increase in the number of lung transplants, a decrease in waitlist deaths and removals, and changes in median distance between donor hospital and transplant center.
    • Exception Scores: The number of exception scores has increased, allowing for adjustments when the assigned score may not reflect the patient’s true medical urgency.
    • Caution and Early Analysis: Early data, while promising, is subject to caution as centers were aware of the upcoming change. The impact on different age groups and the reasons for exceptions are being closely monitored and may evolve as more data becomes available.
  2. Ongoing Monitoring and Potential Evolution: The data is being closely tracked by medical directors, and further changes to the scoring system may occur based on ongoing analysis and experience with the CAS. The impact on patient outcomes and allocation efficiency will continue to be studied and refined.

Advising patients on what to expect in terms of prognosis and survival after lung transplant

  1. Survival Statistics:
    • Overall three is approximately 50 percent survival at five years, and the median survival time is approximately six and a half years.
    • Significant variations based on factors such as diagnosis, age, and comorbidities.
    • Survival outcomes differ for specific groups, e.g., cystic fibrosis (CF) patients, those older than 65, and individuals with interstitial lung disease (ILD).
  2. Quality of Life Emphasis:
    • Shift in focus from survival alone to the patient’s goals and quality of life.
    • Highlighting the importance of understanding and aligning with the patient’s individual quality of life expectations.
  3. Investment in Healthcare Team and Lifestyle Change:
    • Emphasis on the long-term commitment and involvement with the healthcare team post-transplant.
    • A substantial investment in healthcare post-transplant, including regular visits, extensive blood work, and medication management.
    • Cultural shift for patients to adapt to a new routine of frequent medical visits even when otherwise healthy.
  4. Complications and Side Effects:
    • Acknowledgment of potential complications within the first year, making the initial post-transplant period a full-time job.
    • Discussion of various complications and medication side effects, ensuring patients are informed.
    • Multidisciplinary approach involving nutritionists, physical therapists, and other specialists to address complications and enhance the patient’s quality of life.
  5. Individualized Patient Approach:
    • Recognition of the patient’s fight, spirit, and motivation as crucial factors for successful transplantation.
    • Encouraging patients to set goals for their post-transplant life.
    • Ethical considerations regarding transplanting older patients, with the importance of assessing overall well-being, motivation, and mental health.
  6. Acknowledgment of Averages and Unpredictability:
    • Communication of averages, but a reminder of the inherent unpredictability in the post-transplant course.
    • Preparing patients for potential complications and the need to adapt to unforeseen challenges.
    • Managing expectations by highlighting the unpredictability of individual transplant journeys.
  7. Quality of Life Improvement:
    • Despite complications and side effects, lung transplant often results in a significant improvement in the patient’s quality of life.
    • Patients generally experience increased satisfaction and happiness post-transplant, outweighing the challenges associated with the procedure and subsequent care.

References for further reading

  1. Leard LE, Holm AM, Valapour M, Glanville AR, Attawar S, Aversa M, Campos SV, Christon LM, Cypel M, Dellgren G, Hartwig MG, Kapnadak SG, Kolaitis NA, Kotloff RM, Patterson CM, Shlobin OA, Smith PJ, Solé A, Solomon M, Weill D, Wijsenbeek MS, Willemse BWM, Arcasoy SM, Ramos KJ. Consensus document for the selection of lung transplant candidates: An update from the International Society for Heart and Lung Transplantation. J Heart Lung Transplant. 2021 Nov;40(11):1349-1379. doi: 10.1016/j.healun.2021.07.005. Epub 2021 Jul 24. PMID: 34419372; PMCID: PMC8979471.
  2. van der Mark SC, Hoek RAS, Hellemons ME. Developments in lung transplantation over the past decade. Eur Respir Rev. 2020 Jul 21;29(157):190132. doi: 10.1183/16000617.0132-2019. PMID: 32699023; PMCID: PMC9489139.
  3. Valapour M, Lehr CJ, Wey A, Skeans MA, Miller J, Lease ED. Expected effect of the lung Composite Allocation Score system on US lung transplantation. Am J Transplant. 2022 Dec;22(12):2971-2980. doi: 10.1111/ajt.17160. Epub 2022 Aug 9. PMID: 35870119.
  4. Arcasoy SM, Kotloff RM. Lung transplantation. N Engl J Med. 1999 Apr 8;340(14):1081-91. doi: 10.1056/NEJM199904083401406. PMID: 10194239.

Radiology Rounds – 11/21/23

We’re back with another #RadiologyRounds by Pulm PEEPs Associate Editor Tess Litchman. An immunosuppressed 65-year-old man presents with neutropenic fever. He is started on empiric broad-spectrum antibiotics with vancomycin and zosyn. Serum beta-D-glucan is positive.

Further, workup reveals a positive serum galactomannan and a BAL PCR that is positive for Aspergillus. The patient is diagnosed with invasive aspergillosis and started on voriconazole. A repeat CT is obtained in 3 weeks. What do you think of the evolving findings?

58. Implications of Race-Neutral PFTs on Lung Cancer Surgery

We are excited to bring you a fantastic episode today where we are joined by two guest experts to discuss the recent JAMA Surgery manuscript, “Clinical Implications of Removing Race-Corrected Pulmonary Function Tests for African American Patients Requiring Surgery for Lung Cancer

Meet our Guests

Sidra Bonner is a general surgery resident at Michigan Medicine. She completed her undergraduate education at Cornell University and medical education at the University of California-San Francisco. Sidra also has a Master’s in Public Health focused in Health Policy from Harvard and a Master’s in Science Health and Healthcare Research from the University of Michigan. She is interested in pursuing a career in general thoracic surgery with a research focus aimed at addressing the multi-level contributors to racial and ethnic inequities in access, quality, and outcomes of surgical care for patients with lung and esophageal cancer.

Tom Valley is an Associate Professor in the Division of Pulmonary and Critical Care Medicine at the University of Michigan. He completed his IM residency and chief residency at the University of Texas-Southwestern/Parkland Memorial Hospital and then joined the University of Michigan as a pulmonary and critical care fellow in 2013 and stayed on for faculty and is the physician-lead for the University of Michigan Schwartz Rounds for Compassionate Care. Tom’s research aims to understand and improve medical decision making in the intensive care unit.

Radiology Rounds – 11/07/23

We are excited to bring you another #RadiologyRounds

We have a middle-aged immunocompromised male presenting with neutropenic fevers, progressive cough and dyspnea. He has no sick contacts or recent travel.

He was found to have primarily right upper alveolar opacities and blunting of the right costophrenic angle. He rapidly decompensated with acute hypoxemic respiratory failure requiring mechanical ventilation. A CT chest showed dense consolidations with air bronchograms.

The urinary antigen and sputum culture were positive for Legionella and the patient was continued on Macrolide therapy. See our infographic for high-yield teaching points for Legionnaires’ Disease

57. Rapid Fire Journal Club 3 – ETHOS

Rapid Fire Journal Club returns with a deep dive into the 2020 ETHOS Trial published in The New England Journal of Medicine examining triple therapy for moderate to severe COPD. Pulm PEEPs Associate Editor Luke Hedrick takes us through this fascinating study and breaks down some of the intricacies.

Article and Reference

Today we’re talking about the 2020 ETHOS Trial in NEJM

Reference: Rabe KF, Martinez FJ, Ferguson GT, Wang C, Singh D, Wedzicha JA, Trivedi R, St Rose E, Ballal S, McLaren J, Darken P, Aurivillius M, Reisner C, Dorinsky P; ETHOS Investigators. Triple Inhaled Therapy at Two Glucocorticoid Doses in Moderate-to-Very-Severe COPD. N Engl J Med. 2020 Jul 2;383(1):35-48. doi: 10.1056/NEJMoa1916046. Epub 2020 Jun 24. PMID: 32579807.

Infographic

This can be downloaded on our website and will be shared on Twitter and Instagram.

56. Bedside Teaching in the ICU – Pulm PEEPs and ATS Breathe Easy

This week on Pulm PEEPs, we are excited to be cross-posting an episode that Dave Furfaro did on the ATS Breathe Easy Podcast. Listen to hear a discussion about the best way to create a positive learning environment in the ICU, and how to effectively prepare bedside teaching for learners of all levels.

Meet The Host

Matthew Stutz hosted this episode of the ATS Breathe Easy Podcast. He is an Attending Pulmonary and Critical Care physician at Cook County Health and an Assistant Professor at Rush University. He is a dedicated educator and an active member of the American Thoracic Society.

Key Learning Points

  1. Empowerment: It’s crucial to empower both learners and teachers in an educational setting.
  2. Open Communication: Learners should be encouraged to express their discomfort or challenges in learning. This will allow teachers to adapt and create a more effective learning environment.
  3. Self-awareness and Continuous Improvement: Teachers should be self-aware and continuously strive for improvement. If a teacher knows their weak points or areas they want to enhance, such as bedside teaching or teaching on rounds, they should communicate this to their team. This will make the team more observant and supportive in giving feedback.
  4. Honesty: A genuine and honest dialogue helps in building a strong and trusting educational relationship. It’s beneficial for both the teacher and learner to be candid about their needs and challenges.
  5. Feedback Mechanism: Constructive feedback is an essential part of growth. By informing team members of areas you’re working on, you can receive specific and helpful feedback at the end of a rotation or session.
  6. Appreciation: It’s important to appreciate and acknowledge contributions in an educational or collaborative setting.

55. The Autumn Ghost

We are excited to bring you a special episode where we are joined by author Dr. Hanna Wunsch and will discuss her book, “The Autumn Ghost: How the Battle Against a Polio Epidemic Revolutionized Modern Medical Care.

Meet our Guests

Dr. Hannah Wunsch a Professor of Anesthesiology and Critical Care Medicine at the University of Toronto and is an intensivist at Sunnybrook Hospital. Hannah completed her medical training at Washington University School of Medicine and  received a Master’s Degree in Epidemiology from the London School of Hygiene and Tropical Medicine. She completed her anesthesia residency and critical care fellowship at Columbia University in New York and was on faculty there for 6 years prior to moving to Toronto. The Autumn Ghost is her first book.

In The Autumn Ghost, Dr. Hannah Wunsch shares the story of the polio epidemic in the autumn of 1952 in Copenhagen. She masterfully tells the story of how specialties came together to advance mechanical ventilation and intensive care units, and connects history to modern day medicine.

54. Top Consults: Solitary Pulmonary Nodule

We are thrilled to be back with another episode in our Top Consults series. We are talking about Solitary Pulmonary Nodules, which is something every pulmonologist will encounter in the clinic and on in-patient consults. We go through a number of cases and provide a framework for approaching these cases.

Meet our guests

Dr. Jessica Wang Memoli is board certified in pulmonary disease, critical care medicine and internal medicine. She is the Director of Bronchoscopy and Interventional Pulmonary, as well as the Associate Fellowship Program Director for Pulmonary Critical Care Medicine at the MedStar Washington Hospital Center. Dr. Wang Memoli received her medical degree from the University of Miami Miller School of Medicine. She completed her residency at MedStar Washington Hospital Center and her fellowship training at the Medical University of South Carolina in Charleston.

Dr. Nick Ghionni works at Union Memorial, Good Samaritan, and Franklin Square as an Intensivist and Pulmonologist. He completed his Internal Medicine residency at Mercy Catholic Medical Center in PA serving as Chief Internal Medicine resident. He was a fellow at MedStar Washington Hospital Center where he was the Chief Pulmonary Critical Care Fellow. His specific interests include mechanical ventilation, POCUS, and medical education.

Case Presentations

Case 1:

33 year old woman who came to the emergency department with acute onset of shortness of breath. She states that she had been in her normal state of health until this morning when she developed shortness of breath at rest, and chest pain. She does report a non-productive cough over the last few weeks which she feels may be contributing to her chest pain. She does report a history of asthma during childhood but without any exacerbations or maintenance therapies needed during her adulthood. She does report wheezing when she is sick with a cold but this is infrequent. The ED team sent off an initial work-up including a D-Dimer which was elevated, and she underwent a CTA of the chest for concern for possible PE. On the CT scan, there was no PE but the radiologist did call a “2 mm indeterminate right upper lobe pulmonary nodule.”

Case 2:

We have a 67-year-old male with a past medical history of ischemic cardiomyopathy, chronic systolic heart failure (LVEF 10-15%), s/p AICD, diabetes mellitus type 2, hyperlipidemia, hypertension, chronic kidney disease stage III, prostate cancer s/p seed implantation that was over 15 years ago who presented with acute decompensation of his heart failure and cardiogenic shock. He was successfully managed for that and is now being worked up by advanced HF and as a part of that workup got a chest CT, which found a RUL 6 mm nodule.

Case 3:

We have a 66-year-old male with a past medical history of HTN and drug abuse who presented to the ED with acute SOB, likely a COPD exacerbation. He was given bronchodilator and steroids as well as being started on Bipap. He eventually was able to be weaned off Bipap and was able to tolerate nasal cannula. As a part of his initial work up, the patient underwent CT scan for possible PE which demonstrated a new LUL spiculated nodule that is 1.3cm that is new since 2019.

Key Learning Points

Approaching Pulmonary Nodules:

  1. A structured approach is essential due to the complexities of diagnosing pulmonary nodules.
  2. Patient history, including risk factors, past interventions, and imaging, plays a vital role.
  3. Nodules’ appearance, such as location, shape, or characteristics like calcification or spiculation, can provide diagnostic clues.
  4. The nodules history on serial imaging is a key predictive risk factor for determining the likelihood that the nodule represents cancer
  5. Tools like the Mayo Risk Calculator and Fleishner Society guidelines assist in risk assessment and guidance.
  6. It’s essential to assess patient risk, and nodule risk, and prioritize patient concerns and education. Periodic monitoring or follow-up might be necessary based on the nodule’s risk and size.
  7. A multidisciplinary approach involving various specialists ensures comprehensive care.

Key Discussion Points:

PET Scans:

  1. Useful in gauging a nodule or tumor’s metabolic activity.
  2. Large, hypermetabolic nodules are suspicious.
  3. Not every positive PET result means malignancy; other causes like inflammation or scars can produce positive results.

Evaluating Nodules:

  1. Consideration of nodule size, characteristics, patient history, and risk calculators is crucial.
  2. Tumor boards provide a collaborative expertise approach.

Tissue Sampling & Testing:

  1. The method of tissue sampling depends on resources and expertise.
  2. CT-guided biopsy offers a high diagnostic yield but with a risk of pneumothorax.
  3. Bronchoscopic biopsy provides a lower diagnostic yield than CT-guided biopsy but has a significantly reduced risk of complications.
  4. Advanced diseases now often require molecular testing on tissue samples.

Ground Glass Nodules:

  1. Different from solid nodules due to their slow growth rate.
  2. Monitoring is crucial due to the potential for transformations raising cancer suspicions.
  3. The approach for ground glass nodules typically involves more extended monitoring intervals than for solid nodules.

Holistic Evaluation:

  1. Consider the nodule’s characteristics, the patient’s history, and clinical intuition.
  2. Individualized patient assessment is as vital as evidence-based guidelines and clinical expertise.

See the infographic for a summary of key learning points:

References and further reading

Loverdos K, Fotiadis A, Kontogianni C, Iliopoulou M, Gaga M. Lung nodules: A comprehensive review on current approach and management. Ann Thorac Med. 2019 Oct-Dec;14(4):226-238. doi: 10.4103/atm.ATM_110_19. PMID: 31620206; PMCID: PMC6784443.

Mazzone PJ, Lam L. Evaluating the Patient With a Pulmonary Nodule: A Review. JAMA. 2022 Jan 18;327(3):264-273. doi: 10.1001/jama.2021.24287. PMID: 35040882.

MacMahon H, Naidich DP, Goo JM, Lee KS, Leung ANC, Mayo JR, Mehta AC, Ohno Y, Powell CA, Prokop M, Rubin GD, Schaefer-Prokop CM, Travis WD, Van Schil PE, Bankier AA. Guidelines for Management of Incidental Pulmonary Nodules Detected on CT Images: From the Fleischner Society 2017. Radiology. 2017 Jul;284(1):228-243. doi: 10.1148/radiol.2017161659. Epub 2017 Feb 23. PMID: 28240562.

Wahidi MM, Govert JA, Goudar RK, Gould MK, McCrory DC; American College of Chest Physicians. Evidence for the treatment of patients with pulmonary nodules: when is it lung cancer?: ACCP evidence-based clinical practice guidelines (2nd edition). Chest. 2007 Sep;132(3 Suppl):94S-107S. doi: 10.1378/chest.07-1352. PMID: 17873163.

Godoy MC, Sabloff B, Naidich DP. Subsolid pulmonary nodules: imaging evaluation and strategic management. Curr Opin Pulm Med. 2012 Jul;18(4):304-12. doi: 10.1097/MCP.0b013e328354a5f2. PMID: 22575798.

Hammer MM, Hatabu H. Subsolid pulmonary nodules: Controversy and perspective. Eur J Radiol Open. 2020 Sep 4;7:100267. doi: 10.1016/j.ejro.2020.100267. PMID: 32944597; PMCID: PMC7481135.