Utility of FDG-PET-CT scanning in assessing the extent of disease activity and response to treatment in sarcoidosis

Management of Isolated Thoracic Lymphadenopathy of Unclear Etiology: A Survey of Physicians and Literature Review

Background After identifying incidental mediastinal lymph nodes, decisions need to be made regarding the required follow-up imaging, the intervals at which this imaging should be performed, the types of imaging and procedures needed, and when to discontinue the follow-up. The purpose of this study is to determine the majority opinion on the management of these findings and provide recommendations for future management of incidental mediastinal lymphadenopathy.  Methodology Sixty-two healthcare providers from a variety of specializations were surveyed on their preference for diagnostic workup and subsequent follow-up following the finding of incidental mediastinal lymphadenopathy on computed tomography (CT) of the chest. Results For thoracic lymphadenopathy of unclear etiology and patients who are not offered endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), most providers (47/62, 75.8%) initiate the CT scan follow-up at size 10 to 14 mm. Of those patients, 51.6% (32/62) of providers repeat the initial CT scan in three months and 41.9% (26/62) repeat the initial CT scan in six months. If the follow-up CT chest shows stable lymphadenopathy, 47.5% (29/62) repeat a CT chest every six months and 37% (23/62) repeat a CT chest every 12 months. The majority of providers (42/62, 67.7%) do not use positron emission tomography (PET)-CT for the initial evaluation of isolated thoracic lymphadenopathy and follow-up of lymphadenopathy with increasing size. For thoracic lymph nodes with a maximum diameter of 10 mm, only 4.8% (3/62) of providers continue CT screening after 24 months, while 24.6% (15/62) of providers continue CT screening after 24 months for sizes greater than 20 mm. Regarding the timing of EBUS-TBNA, 40.3% (25/62) of providers consider referring/performing this procedure at lymph nodes of size 11-15 mm, followed by 21% (13/62) of providers referring/performing the procedure at size 10 mm. Conclusions The majority of providers initiate CT scan follow-ups at 10 to 14 mm size for patients with isolated thoracic lymphadenopathy. The majority of providers do not use PET-CT for the initial evaluation of isolated thoracic lymphadenopathy. We found variable responses from providers regarding the timing of follow-up intervals and total duration. There is a need for consensus guidelines regarding the management of thoracic lymphadenopathy of unclear etiology.

Nonmalignant Thoracic Disorders: An Appraisal of Fluorodeoxyglucose and Non-fluorodeoxyglucose PET/Computed Tomography Applications

PET/computed tomography (CT) with fluorodeoxyglucose and nonfluorodeoxyglucose PET tracers has established itself in the management of malignant disorders. Its role in the assessment of nonmalignant conditions, such as infectious and noninfectious inflammatory diseases and other benign conditions, has emerged independently and alongside its role being evaluated in malignancy and continues to evolve. It is evident that PET/CT has the potential to play a significant role in various nonmalignant disorders of the thorax. This review highlights current developments and areas where PET/CT has a potential to impact the clinical management of nonmalignant thoracic conditions with special focus on nonfluorodeoxyglucose tracers.

Patient profile and comparison of three diagnostic criteria for cardiac sarcoidosis in a tuberculosis endemic population

BACKGROUND

Cardiac sarcoidosis (CS) is an underdiagnosed and life-threatening condition. Histopathological diagnosis is difficult due to the risks and variable diagnostic yield of endomyocardial biopsy.

OBJECTIVES

To study the clinical profile and compare the diagnostic criteria of CS in a cohort of sarcoidosis.

METHODS

A retrospective review of the Sarcoidosis database (375 patients) was performed to identify patients with CS. Demographic and clinical details were retrieved. We applied the available diagnostic criteria for the diagnosis of CS: The World Association of Sarcoidosis and Other Granulomatous Diseases (WASOG), Heart Rhythm Society (HRS), and Japanese Ministry of Health and Welfare (JMHW) criteria.

RESULTS

Out of the 375 patients, 15 (4%) were identified with CS. The median age was 41 years, and 53% were female. The most common symptoms were breathlessness, palpitation, and fatigue in 80%, 53.3%, and 46.6% of patients, respectively. Tuberculin positivity (≥ 10mm induration) was seen in 26.6%. 80% and 53.3% of the patients had abnormal ECG and 2D echocardiography findings, respectively. Six patients had a history of Ventricular tachycardia (40%). LV Ejection fraction was reduced in 12 subjects (80%). Cardiac-MRI showed late gadolinium enhancement in 53.3%. A definitive histopathological diagnosis for sarcoidosis was established in 86.6% (13/15) patients. Of the 15, all satisfied JMHW criteria and WASOG criteria (12 (80%) at least probable category, 3 (20%) possible CS), and 13 (86.6%) met HRS criteria for a diagnosis of CS.

CONCLUSION

In a cohort of 375 patients with sarcoidosis in a tuberculosis endemic setting, 4% were diagnosed with cardiac sarcoidosis. Histopathological diagnosis may be obtained by sampling from extracardiac sites. JMHW and WASOG criteria perform equally well in TB endemic settings.

Clinical Profile of 327 patients with Sarcoidosis in India: An Ambispective Cohort Study in a Tuberculosis (TB) Endemic Population

Introduction:

Sarcoidosis is a multisystem granulomatous disease with a varied clinical presentation. We describe the clinical characteristics of patients with sarcoidosis from a tuberculosis (TB) endemic setting.

Methods:

We performed an analysis of the sarcoidosis database at a tertiary care facility in North India.

Results:

Of the 327 patients, 50.8% were male, with a mean age of 42.8 years (range: 16–70 years). Females were significantly older. 42.6% had comorbidities, of which diabetes (17.1%) was most common. More than half (57.1%) were obese. Serum angiotensin-converting enzyme levels were elevated in 186 (57.9%). Eleven (3.8%) had hypercalcemia, while hypercalciuria was present in 54 (31.7%). The majority (89.9%) were tuberculin skin test negative (<10 mm induration), while 71.9% were tuberculin anergic. 47.7% had normal spirometry, while a restrictive impairment was the most common abnormality (44.6%). Obstruction on spirometry was present in 8.3%. Nearly half (160, 49%) had involvement of an extrapulmonary site. Most patients were (96%) symptomatic. Cough, shortness of breath, fatigue, weight loss, and fever were the predominant symptoms. A majority had Stage 1 (47.7%) sarcoidosis. Two hundred and eighty-seven (87.8%) patients underwent bronchoscopy or endosonographic (endobronchial ultrasound-guided transbronchial needle aspiration [EBUS-TBNA] or transesophageal bronchoscopic ultrasound-guided fine-needle aspiration [EUS-B-FNA]) sampling. A histopathological diagnosis with the demonstration of granulomas was achieved in 90.8%. The diagnostic yield of EBUS-TBNA/EUS-B-FNA was 77.4%. In 13.5% of patients, necrotizing granulomas were present in tissue samples.

Conclusion:

The clinical profile of patients with sarcoidosis in TB endemic settings has certain differences from nonendemic populations. Bronchoscopy and endosonography allow a confident diagnosis in the majority of patients.

Subhepatic Abscess Unmasking the Silent Gastric and Pulmonary Sarcoidosis

Sarcoidosis is a non-necrotizing granulomatous disease of unknown etiology presenting with variable systemic manifestations. Lung involvement is the most common initial presentation of sarcoidosis. Rarely, patients can present with initial non-pulmonary symptoms. Asymptomatic gastric sarcoidosis is a difficult diagnosis as it is not only rare but also under-recognized in the majority of cases. Its treatment is exclusively recommended for symptomatic cases only. However, it is of extreme significance to have the asymptomatic patients follow up outpatient regularly to prevent any major complications. Here, we present an interesting case of a 54-year-old African American female patient with only abdominal pain symptoms attributed to a hepatic abscess. A diagnosis of gastric sarcoidosis was solely based on the presence of non-necrotizing granulomas on biopsy following esophagogastroduodenoscopy (EGD). Incidentally, she was also found to have pulmonary sarcoidosis based on imaging. Her abdominal symptoms improved with abscess drainage and so, she was never started on steroids. She was followed up outpatient for pulmonary function tests. The patient continues to do well without any specific treatment for sarcoidosis. This case demonstrates the variability of sarcoidosis and the significance of biopsy in gastric sarcoidosis.

Mediastinal lymphadenopathy: a practical approach

Introduction: Mediastinal lymphadenopathy is secondary to various benign and malignant etiologies. There is a variation in the underlying cause in different demographic settings. The initial clue to the presence of enlarged mediastinal lymph nodes is through thoracic imaging modalities. Malignancy (Lung cancer, lymphoma, and extrathoracic cancer) and granulomatous conditions (sarcoidosis and tuberculosis) are the most common causes. For a confident diagnosis, the clinician must choose from several available options and integrate the clinical, radiological, and pathology findings. An accurate diagnosis is necessary for optimal management.Areas covered: We performed a search of the PUBMED database to identify relevant articles on the causes, imaging modalities, and interventional modalities to diagnose these conditions. We discuss a practical approach toward the evaluation of a patient with mediastinal lymphadenopathy.Expert opinion: Mediastinal lymphadenopathy is a commonly encountered clinical problem. Treating physicians need to be aware of the clinico-radiological manifestations of the common diagnostic entities. Selecting an appropriate tissue diagnosis modality is crucial, with an intent to use the least invasive technique with good diagnostic yield. Endosonographic modalities (EBUS-TBNA, EUS-FNA, and EUS-B-FNA) have emerged as the cornerstone to most patients' diagnosis. An accurate diagnosis translates into favorable treatment outcomes.

Unsupervised Clustering Reveals Sarcoidosis Phenotypes Marked by a Reduction in Lymphocytes Relate to Increased Inflammatory Activity on 18FDG-PET/CT

Introduction: Sarcoidosis is a T-helper cell mediated disease characterized by granulomatous inflammation. We posited that unsupervised clustering of various features in sarcoidosis would establish phenotypes associated with inflammatory activity measured by 18FDG-PET/CT. Our goal was to identify unique features capable of distinguishing clusters and subsequently examine the relationship with FDG avidity to substantiate their potential use as markers for sarcoidosis inflammation.

Methods: We performed a retrospective study of a diverse, but primarily African American, cohort of 58 subjects with biopsy proven sarcoidosis followed at the University of Illinois Bernie Mac Sarcoidosis Center and Center for Lung Health who underwent 18FDG-PET/CT scan. Demographic, therapeutic, radiographic, and laboratory data were utilized in unsupervised cluster analysis to identify sarcoidosis phenotypes. The association between clusters, their defining features, and quantitative measurements on 18FDG-PET/CT was determined. The relevance of these features as markers of 18FDG-PET/CT inflammatory activity was also investigated.

Results: Clustering determined three distinct phenotypes: (1) a predominantly African American cluster with chronic, quiescent disease, (2) a predominantly African American cluster with elevated conventional inflammatory markers, advanced pulmonary disease and extrathoracic involvement, and (3) a predominantly Caucasian cluster characterized by reduced lymphocyte counts and acute disease. In contrast to the chronic quiescent cluster, Clusters 2 and 3 were defined by significantly greater FDG avidity on 18FDG-PET/CT. Despite similarly increased inflammatory activity on 18FDG-PET/CT, Clusters 2, and 3 differed with regards to extrathoracic FDG avidity and circulating lymphocyte profiles, specifically CD4+ T-cells. Notably, absolute lymphocyte counts and CD4+ T-cell counts were found to predict 18FDG-PET/CT inflammatory activity by receiver operating curve analysis with a 69.2 and 73.42% area under the curve, respectively.

Conclusions: Utilizing cluster analysis, three distinct phenotypes of sarcoidosis were identified with significant variation in race, disease chronicity, and serologic markers of inflammation. These phenotypes displayed varying levels of circulating inflammatory cells. Additionally, reduction in lymphocytes, specifically CD4+ T-cells, was significantly related to activity on 18FDG-PET/CT. Though future studies are warranted, these findings suggest that peripheral lymphocyte counts may be considered a determinant of sarcoidosis phenotypes and an indicator of active inflammation on 18FDG-PET/CT.

In Which Patients with Sarcoidosis Is FDG PET/CT Indicated?

Sarcoidosis is a granulomatous disease of which the etiology remains unknown. The diverse clinical manifestations may challenge clinicians, particularly when conventional markers are inconclusive. From various studies, it has become clear that fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT aids in sarcoidosis care. In this article, an update on FDG PET/CT in sarcoidosis is provided. The use of FDG PET/CT in the diagnostic process of sarcoidosis is explained, especially in determining treatable inflammatory lesions in symptomatic patients with indecisive conventional tests. Furthermore, FDG PET/CT for evaluating the potential benefit of additional inflammatory treatment is described and its use in cardiac sarcoidosis is highlighted.

FDG-PET/CT Assessment of Pulmonary Sarcoidosis: A Guide for Internists

BACKGROUND

18F-fluorodeoxyglucose positron emission tomography integrated with computed tomography (18-F-FDG-PET/CT) is getting wide consensus in the diagnosis and staging of neoplastic disorders and represents a useful tool in the assessment of various inflammatory conditions.

DISCUSSION

Sarcoidosis is an uncommon disease characterized by the systemic formation of noncaseating granulomas. Lungs are the sites most often affected, and investigation with high resolution computed tomography and biopsy is essential to achieve a correct diagnosis. 18-F-FDGPET/ CT is effective in the assessment of pulmonary sarcoidosis by demonstrating pulmonary and extrathoracic involvement and findings correlate well with pulmonary function in patients affected.

CONCLUSION

This review would illustrate the usefulness and limits of 18-F-FDG-PET/CT in the assessment of pulmonary sarcoidosis.

Semi-quantitative metabolic values on FDG PET/CT including extracardiac sites of disease as a predictor of treatment course in patients with cardiac sarcoidosis

Background

Cardiac sarcoidosis is associated with major adverse cardiac events including cardiac arrest, for which anti-inflammatory treatment is indicated. Oral corticosteroid is the mainstay among treatment options; however, adverse effects are a major concern with long-term use. It would be beneficial for providers to predict treatment response and prognosis for proper management strategy of sarcoidosis, though it remains challenging. Fluorine (F)-18 fluorodeoxyglucose (FDG)-positron emission tomography(PET)/computed tomography(CT) has an advantage over anatomical imaging in providing semi-quantitative functional parameters such as standard uptake value (SUV), metabolic volume, and total lesion glycolysis (TLG), which are well-established biomarkers in oncology. However, the relationship between these parameters and treatment response has not been fully investigated in cardiac sarcoidosis. Also, the prognostic value of extracardiac active inflammation noted on FDG-PET/CT in the setting of cardiac sarcoidosis is unclear. The aim of this retrospective study was to investigate the prognostic value of semi-quantitative values of both cardiac and extracardiac disease sites derived from FDG-PET/CT in predicting treatment course in cardiac sarcoidosis.

Methods

Sixteen consecutive patients with suspected cardiac sarcoidosis, who demonstrated abnormal myocardial activity on cardiac-inflammation FDG-PET/CT encompassing the entire chest/upper abdomen and subsequently underwent corticosteroid therapy for diagnosis of active cardiac sarcoidosis, were included. Semi-quantitative values of hypermetabolic lesions were derived from all visualized organ system and were compared to daily corticosteroid dose at 6 months.

Results

 Of the 16 patients, 81.3% (13/16) of the patients showed extracardiac involvement. The lesion with the greatest SUV was identified in the heart in 11 patients (68.7%), in the liver in 1 patient (6.3%), and in lymph nodes in 4 patients (25%). The maximum SUV across all visualized organ systems including the heart were 8.8 ± 3.1 for the patients with corticosteroid dose ≤ 10 mg and 12.5 ± 3.3 for those with > 10 mg (P = 0.04). Metabolic volume and TLG across all visualized organ systems or any values in the heart alone showed no significant statistical difference between the two groups.

Conclusions

Maximum SUV across all involved organ-systems of the chest and upper abdomen, not that of the heart alone, could be a predictor of treatment course of steroid therapy at 6 months in patients with active cardiac sarcoidosis.

Gastric and pulmonary sarcoidosis complicated by hypercalcemia and acute renal failure: Case report and literature review

Gastric sarcoidosis is a very rare manifestation of sarcoidosis. Only few case reports have been described in the literature. We present a case of coexisting gastric and pulmonary sarcoidosis in a 56-year-old female, who presented with gastrointestinal symptoms. Gastric mucosal biopsies, transbronchial needle aspiration, and endobronchial mucosal biopsies revealed noncaseating granulomas. This case report emphasizes on early evaluation of other organ system and initiation of treatment.

Optimization of Pediatric PET/CT

PET/CT, the most common form of hybrid imaging, has transformed oncologic imaging and is increasingly being used for nononcologic applications as well. Performing PET/CT in children poses unique challenges. Not only are children more sensitive to the effects of radiation than adults but, following radiation exposure, children have a longer postexposure life expectancy in which to exhibit adverse radiation effects. Both the PET and CT components of the study contribute to the total patient radiation dose, which is one of the most important risks of the study in this population. Another risk in children, not typically encountered in adults, is potential neurotoxicity related to the frequent need for general anesthesia in this patient population. Optimizing pediatric PET/CT requires making improvements to both the PET and the CT components of the procedure while decreasing the potential for risk. This can be accomplished through judicious performance of imaging, the use of recommended pediatric ¹⁸fluorine-2-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) administered activities, thoughtful selection of pediatric-specific CT imaging parameters, careful patient preparation, and use of appropriate patient immobilization. In this article, we will review a variety of strategies for radiation dose optimization in pediatric ¹⁸F-FDG-PET/CT focusing on these processes. Awareness of and careful selection of pediatric-specific CT imaging parameters designed for appropriate diagnostic, localization, or attenuation correction only CT, in conjunction with the use of recommended radiotracer administered activities, will help to ensure image quality while limiting patient radiation exposure. Patient preparation, an important determinant of image quality, is another focus of this review. Appropriate preparative measures are even more crucial in children in whom there is a higher incidence of brown fat, which can interfere with study interpretation. Finally, we will discuss measures to improve the patient experience, the resource use, the departmental workflow, and the diagnostic performance of the study through the use of appropriate technology, all in the context of minimizing procedure-related risks.