Nuclear imaging. 67Gallium, 201thallium, 18F-labeled fluoro-2-deoxy-D-glucose positron emission tomography

Cardiac Sarcoidosis: A Review of Contemporary Challenges in Diagnosis and Treatment

Sarcoidosis is a systemic disease characterized by noncaseating granulomas and is often a diagnosis of exclusion. The actual prevalence of cardiac sarcoidosis (CS) is unknown, as studies have demonstrated mixed data. CS may be asymptomatic and is likely more frequently encountered than previously thought. Sudden death may often be the presenting feature of CS. Most deaths attributed to CS are caused by arrhythmias or conduction system disease, and congestive heart failure may occur. Current expert consensus on diagnosis of CS continues to rely on endomyocardial biopsy, in the absence of which, histologic proof of extracardiac sarcoid involvement is necessitated. Emergence of newer noninvasive imaging modalities such as cardiac magnetic resonance imaging and positron emission tomography, have become increasingly popular tools utilized in patients with both clinical and asymptomatic CS, and have demonstrated good diagnostic capability. The main therapeutic approaches in patients with CS can be broadly divided into the following 2 categories: pharmacological management and invasive or device oriented. However, much remains unknown about the optimal screening protocols of asymptomatic patients with extracardiac sarcoidosis and treatment of biopsy-proven CS. Our knowledge about CS has amplified significantly over the last 30 years and the growing realization that this process is often asymptomatic is paving the way for better screening protocols and earlier detection of this serious condition.

Worsening of pulmonary sarcoidosis

PURPOSE OF REVIEW

Despite the frequent occurrence of worsening pulmonary symptoms in pulmonary sarcoidosis patients, there is little available information concerning this topic.

RECENT FINDINGS

In this review, we outline the various causes for these symptoms. We propose to partition the various causes for these symptoms into specific categories.

SUMMARY

We believe that these categories will provide the clinician a framework to evaluate pulmonary sarcoidosis patients with such symptoms in a rigorous way that may be useful in optimizing their care.

Inflammatory optic disc edema due to Sarcoidosis mimicking malignant hypertension

A common ocular manifestation of sarcoidosis is anterior uveitis. Posterior uveitis is uncommon and optic disc edema is rare. We report one such case in which the initial presentation was mimicking malignant hypertension as the patient had a recent record of high blood pressure. However, the painful progressive vision loss due to optic disc edema, along with anterior uveitis, and histological proof of non-caseating granulomas on transbronchial lung biopsy clinched the diagnosis of ocular sarcoidosis. There was complete resolution of signs and symptoms with institution of steroids. There was also probable cardiac involvement. This case highlights the fact that all disc edemas in a diabetic and hypertensive patients is not just due to malignant hypertension, even if there is a recent history of elevated blood pressure.

Lacrimal gland uptake of (67)Ga-gallium citrate correlates with biopsy results in patients with suspected sarcoidosis

PURPOSE

To investigate whether lacrimal gland uptake on (67)Ga-gallium citrate scintigraphy correlates with histopathologic evidence of sarcoidosis.

METHODS

A retrospective, pilot study of 31 patients with suspected sarcoidosis who underwent gallium scintigraphy and lacrimal gland biopsy. Lacrimal gland gallium uptake was assessed by subjective visual scoring (SVS) and lacrimal uptake ratio (LUR).

RESULTS

Eleven (36%) patients had lacrimal gland biopsies containing noncaseating granulomas. A statistically significant correlation was found between lacrimal gland gallium uptake and biopsy positivity using SVS (p = 0.03) or LUR (p = 0.01). Using SVS, biopsy positivity rate increased from 0 to 50% in patients with mild to intense uptake. Using LUR, biopsy positivity rate increased linearly as the ratio increased from 13% (LUR < 4) to 100% (LUR > 8).

CONCLUSIONS

Lacrimal biopsy positivity rate significantly correlated with gallium uptake on scintigraphy. Both SVS and LUR methods appear to correlate with histologic results and may potentially aid in patient selection for biopsy.

A Japanese case of vertebral sarcoidosis

We herein report the first Japanese case of vertebral sarcoidosis diagnosed using multiple imaging modalities and a biopsy. CT, MRI and (18)F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) detected multiple vertebral lesions, and a vertebral biopsy guided by the PET findings confirmed the diagnosis of vertebral sarcoidosis. Although the disease was refractory to corticosteroids, treatment with methotrexate (MTX) achieved a good response. Our case suggests that MRI and 18F-FDG PET are useful for determining the site for a biopsy and that MTX is effective for treating vertebral sarcoidosis.

The puzzling clinical spectrum and course of juvenile sarcoidosis

BACKGROUND

Juvenile sarcoidosis is a rare, chronic, multisystem, granulomatous disease of obscure etiology which is seen in childhood and adulthood. The disease in childhood has a course different from that in adulthood.

DATA SOURCES

PubMed database was searched using terms sarcoidosis, children or childhood sarcoidosis or juvenile sarcoidosis in combination with one of the following terms: epidemiology, clinical manifestations, genetics, diagnosis, treatment, and prognosis. We also retrieved the terms such as early onset sarcoidosis and Blau syndrome. Furthermore, e-medicine and European Respiratory Society monographs for sarcoidosis were reviewed.

RESULTS

Sarcoidosis in childhood presents with two age dependent, distinct forms. In younger children it is clinically evident before the age of four years and characterized by the triad of rash, arthritis and uveitis. In their older counterparts, the juvenile late onset sarcoidosis involves several organs and its clinical appearance resembles the adult type of the disease, with the respiratory system being most frequently affected (hilar lymphadenopathy, pulmonary infiltrations). Steroid is the main agent of treatment whereas methotrexate is also used for beneficial steroid sparing effects. New, novel therapies may change the outcome of the disease especially in difficult morbid cases.

CONCLUSIONS

Sarcoidosis in childhood is recognized as a systemic disease affecting various organs and having diverse clinical course depending on the age of onset.

Cardiac imaging in myocardial sarcoidosis and other cardiomyopathies

PURPOSE OF REVIEW

The clinical role of emerging imaging technologies for diagnosing cardiac sarcoidosis and other cardiomyopathies is evolving. An up-to-date review of the role of various imaging modalities in the evaluation of cardiac sarcoidosis and other cardiomyopathies is presented.

RECENT FINDINGS

No study prospectively established the accuracy of each of the various techniques for diagnosing myocardial involvement in patients with suspected cardiac sarcoidosis. Cardiac magnetic resonance imaging (CMR) is demonstrated to have a sensitivity of 100% and specificity of approximately 80%, and positive predictive value of approximately 55% in diagnosing cardiac sarcoidosis. Recent studies have shown that 18F-2-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) has 100% sensitivity of detecting earlier stages of sarcoidosis. Both the FDG-PET and CMR may provide complementary information for the diagnosis and assessment of efficacy of therapy in patients with cardiac involvement from sarcoidosis.

SUMMARY

Clinical and subclinical cardiac involvement is common among patients with sarcoidosis. A structured clinical assessment incorporating advanced cardiac imaging with CMR and FDG-PET scanning is more sensitive than the established clinical criteria. CMR is an established imaging modality in the diagnosis of various other cardiomyopathies. Well designed prospective clinical trials are awaited to define the exact role of these imaging studies in the diagnosis and guidance of therapy.

Functional imaging of inflammatory diseases using nuclear medicine techniques

Molecular imaging with positron emission tomography (PET) and single-photon emission computed tomography (SPECT) is increasingly used to diagnose, characterize, and monitor disease activity in the setting of inflammatory disorders of known and unknown etiology. These disorders include sarcoidosis, atherosclerosis, vasculitis, inflammatory bowel disease (IBD), rheumatoid arthritis (RA), and degenerative joint disease. Gallium-67 ((67)Ga) citrate, labeled leukocytes with technetium-99m ((99m)Tc) or indium-111 ((111)In), and (18)F-fluorodeoxyglucose (FDG) represent the most widely used radiopharmaceutical agents. However, other preparations, such as labeled murine monoclonal antigranulocyte antibodies and labeled human polyclonal nonspecific immunoglobulin G, chemotactic peptides, interleukins, chemokines, and liposomes, have been used to image inflammation. Also, (99m)Tc nanocolloid scintigraphy has been found to be suitable for bone and joint diseases, especially RA. Among the single photon emitting imaging agents, the recommended radiotracer for abdominal inflammation has been (99m)Tc-hexamethylpropylene amine oxime (HMPAO)-labeled leukocytes. During the last several years, FDG-PET imaging has been shown to have great value for the detection of inflammation and has become the centerpiece of such initiatives. This very powerful technique will play an increasingly important role in the management of patients with inflammatory conditions. FDG-PET can provide valuable information in patients with pulmonary and extrapulmonary sarcoidosis, and is a useful tool for testing the efficacy of various treatments. FDG-PET combined with computed tomography holds great promise for assessing atherosclerosis of the large arteries. This modality is very sensitive in detecting large-vessel vasculitis and can be used to monitor the disease course. FDG-PET is also being used to study the inflamed synovial joints both in the experimental and clinical settings, especially for the investigation and management of RA and degenerative joint disease. This technique also has the potential to become the imaging modality of choice in assessing IBD, replacing radiolabeled autologous leukocyte imaging in this setting. Detection of inflammation in the lungs and airways may improve our knowledge about a multitude of disorders that affect these structures. Therefore, functional imaging, led by FDG-PET imaging, is likely to play an increasingly critical role in assessing inflammatory disorders of known and unknown etiologies, and will improve their management immensely in the future.

Thyroid uptake of 67Ga-citrate is associated with thyroid autoimmunity and hypothyroidism in patients with sarcoidosis

PURPOSE

To evaluate the association of gallium-67 ((67)Ga)-citrate thyroid uptake with the presence of thyroid disorders in patients with sarcoidosis (S patients).

METHODS

Eighty-four S patients were evaluated by a complete thyroid work-up (neck ultrasound, circulating thyroid hormones and anti-thyroid antibodies, fine-needle aspiration).

RESULTS

In S patients with (67)Ga thyroid uptake (respect those without): serum thyroid-stimulating hormone, the titre of anti-thyroid peroxidase (AbTPO) and/or anti-thyroglobulin antibodies (AbTg), and the prevalence of S patients with hypothyroidism or with positive AbTg or AbTPO was significantly higher; a thyroid hypoechoic pattern was more frequent. The prevalence of thyroid nodules was not significantly different between the two groups. Two cases of papillary thyroid cancer were observed in S patients without (67)Ga thyroid uptake, whilst no case in those with (67)Ga thyroid uptake.

CONCLUSIONS

(67)Ga thyroid uptake is associated with the presence of aggressive autoimmune thyroiditis and hypothyroidism in S patients; thyroid function and ultrasonography should be performed in the presence of (67)Ga thyroid uptake.

Sarcoid heart disease

To this day the aetiology of sarcoidosis continues to elude definition. Partially as a consequence of this, little in the way of new therapies has evolved. The enigma of this condition is that, unusually for a disease with the potential for devastating consequences, many patients show spontaneous resolution and recover. Cardiac involvement can affect individuals of any age, gender or race and has a predilection for the conduction system of the heart. Heart involvement can also cause a dilated cardiomyopathy with consequent progressive heart failure. The most common presentation of this systemic disease is with pulmonary infiltration, but many cases will be asymptomatic and are detected on routine chest radiography revealing lymphadenopathy. Current advances lie in the newer methods of imaging and diagnosing this unusual heart disease. This review describes the pathology and diagnosis of this condition and the newer imaging techniques that have developed for determining cardiac involvement.

Imaging of the Lacrimal Gland

The lacrimal gland is situated superolateral to the eye and produces tears that moisten, lubricate, and protect the delicate corneal and conjunctival epithelium. Anatomically related to the orbit but embryologically and functionally more closely related to the salivary glands, radiological imaging has proven invaluable in delineation and differentiation of the unique range of pathological processes affecting the lacrimal gland. This article details traditional and new imaging techniques used in investigating such pathology and discusses the imaging findings and patterns of spread characteristic of various neoplastic, inflammatory, and structural processes ranging from benign adenomas, adenocarcinomas, and lymphomas to sarcoidosis, Mickulicz's syndrome, histiocytosis, and benign dacrocysts.

Heart rate variability in patients with systemic sarcoidosis

PURPOSE

The identification of subjects with systemic sarcoidosis at higher risk for sudden death is an unresolved issue. An influence of the autonomic activity on the genesis of ventricular arrhythmias was postulated. Heart rate variability (HRV) analysis provides a useful method to measure autonomic activity, and is a predictor of increased risk of death in various conditions. Therefore, the aim of the study was to evaluate HRV in patients with systemic sarcoidosis.

METHODS

The study included 35 patients with biopsy proven systemic sarcoidosis who were not taking antiarrhythmic medications. Thallium scintigraphy was performed to all patients with systemic sarcoidosis. The cardiac sarcoidosis was accepted in 16 patients as abnormal thallium scintigraphy and normal coronary arteriography. The time-domain analysis of HRV was expressed as the standard deviation of all normal to normal NN intervals (SDNN) detected during 24-hour Holter monitoring. Twenty-four healthy subjects represented a control group for HRV analysis.

RESULTS

There were no differences in age (44 +/- 13 years for cardiac sarcoidosis, 42 +/- 15 years for noncardiac sarcoidosis, and 40 +/- 10 years for control group; P = NS), sex (the ratio of female; 63%, 68%, and 55%, respectively; P = NS), and echocardiographic ejection fraction (63 +/- 10%, 67 +/- 8%, and 69 +/- 6%, respectively; P = NS) among study groups. The mean SDNN value of the group with cardiac sarcoidosis was significantly lower than both the group with noncardiac sarcoidosis and the control group (72 +/- 32 ms vs 110 +/- 46 ms and 152 +/- 36 ms; P < 0.05, respectively).

CONCLUSION

HRV is decreased in patients with systemic sarcoidosis compared to the control group. This decreasing is more obvious in patients with cardiac sarcoidosis.

Magnetic resonance imaging and nuclear imaging in sarcoidosis

MRI has become of great importance in the study of several aspects of sarcoidosis. The main development has taken place in the assessment of neurosarcoidosis, but MRI may be also useful in the evaluation of sarcoidosis of the bone, muscle, heart, and intrathoracic. Nuclear imaging in sarcoidosis acquired a great expansion with the introduction of (67)gallium scanning as a marker of activity. Although its current use has decreased, it is still very helpful in particular situations of the disease. Other more recently introduced nuclear imaging techniques may have a role in the evaluation of cardiac sarcoidosis and in the assessment of the extension of the disease.

Magnetic resonance imaging after incomplete resection of soft tissue sarcoma

Review of magnetic resonance imaging was compared with the pathologic review of reexcision specimens from 24 pediatric patients who had initial incomplete resection for soft tissue sarcoma to determine the accuracy of magnetic resonance imaging in detecting residual tumor. The median age of patients was 12.8 years. The most common diagnosis was synovial sarcoma (eight of 24 patients; 30%). Magnetic resonance imaging detected residual tumor in eight patients and no tumor in eight patients; the images of eight patients were indeterminate. Pathologic examination showed residual tumor in 14 of 24 (58%) specimens obtained in reexcision. For two of the eight patients (25%) for whom imaging had detected no tumor, microscopic examination detected residual tumor; for one of the eight patients for whom imaging had detected tumor, microscopic examination detected no tumor. Five of the eight patients (63%) for whom the results of imaging studies were indeterminate had residual tumor on microscopic evaluation. The sensitivity of magnetic resonance imaging for detecting residual tumor was 78%, the specificity was 86%, the positive predictive value was 0.78, and the negative predictive value was 0.86. Decisions regarding the need for additional resection should not be based on magnetic resonance imaging alone.

Incidental detection of thoracic sarcoidosis on whole-body 18fluorine-2- fluoro-2-deoxy-D-glucose positron emission tomography

18 Fluorine-2- Fluoro-2-Deoxy-D-Glucose positron emission tomography (18FDG PET) allows imaging of sites with increased metabolic activity. Increased metabolic activity in mediastinal nodes in sarcoidosis has been described. We report the prospective diagnosis of thoracic sarcoidosis on 18FDG PET based on extensive, peripheral, upper lobe parenchymal, and mediastinal nodal tracer uptake.

Löfgren's syndrome revisited: a study of 186 patients

PURPOSE

To evaluate the clinical features, the results of noninvasive tests and biopsies, and the outcome of patients with Löfgren's syndrome.

SUBJECTS AND METHODS

Patients diagnosed as having Löfgren's syndrome at a university hospital in Barcelona, Spain, from 1974 to 1996, were prospectively followed. Löfgren's syndrome was defined as the association of erythema nodosum or periarticular ankle inflammation with unilateral or bilateral hilar or right paratracheal lymphadenopathy.

RESULTS

Löfgren's syndrome was diagnosed in 186 patients. The mean age was 37 +/- 11 years, and 157 (85%) were women. In 91 patients (49%), symptoms started during the spring (P < 0.0001). Erythema nodosum, periarticular ankle inflammation, or both were present at onset in 173 patients (93%). At the time of diagnosis, 161 patients (87%) had no respiratory symptoms; 151 (81%) had stage I abnormalities on chest radiograph, 29 (16%) stage II, and 6 (3%) stage 0. Five percent of patients had decreased forced vital capacity, and 15% had decreased carbon monoxide diffusing capacity. Extrathoracic involvement was infrequent. Serum angiotensin-converting enzyme levels were increased in 50% of patients. Gallium-67 scans showed hilar uptake in all the studied patients, but it yielded useful additional diagnostic information only in those with normal chest radiographs or with unilateral hilar lymphadenopathy. The diagnosis was proven with biopsy results in 63% of patients. None of the patients without histologic confirmation were subsequently found to have a diagnosis other than sarcoidosis. In the 133 patients who were followed for a mean of almost 5 years, 11 (8%) continued to have active disease, and 8 (6%) had several recurrences between 18 months and 20 years after a complete resolution. A normal serum angiotensin-converting enzyme level at diagnosis was associated with disease resolution without recurrence.

CONCLUSION

Löfgren's syndrome is usually a self-limiting form of sarcoidosis. Histologic confirmation is not necessary in typical cases. In a small number of patients, the disease may remain active or recur long after its onset, although usually with mild organ dysfunction.

The clinical management of sarcoidosis. A 50-year experience at the Johns Hopkins Hospital

Sarcoidosis is an enigmatic disease with extremely variable manifestations in pattern, severity and course. Since Longcope and Freiman's descriptive monograph in 1952 (50) summarizing the clinical findings of the first half of this century, new dimensions of assessing the disease and treatment have been added. The impact of corticosteroids is central. The present review extends the studies to the second half of this century. Earlier diagnosis is facilitated and treatment often reverses many of the disease manifestations and improves the quality and extent of life for the patient. The management issues and guidelines outlined in this paper for both intrathoracic and extrathoracic disease are based on several longitudinal studies of the sarcoidosis patients summarized here, and 50 years of clinical experience by the senior author (CJJ) at Johns Hopkins Hospital, a tertiary referral center with an active Sarcoid Clinic. Case reports are presented in the appendix. It is clear that corticosteroids are the most effective therapeutic agent for sarcoidosis, usually with impressive and prompt response. This represents the dramatic difference in this disease after 1950. No more specific or effective immunosuppressive or antiinflammatory agents have been identified. Undesirable side effects are minimal if excessive doses are avoided. The effectiveness of "steroid-sparing agents" such as methotrexate is uncertain. Although irreversible tissue damage from the disease may limit the effectiveness of treatment, benefits of corticosteroids greatly exceed the negative side effects. Since spontaneous remissions without treatment do occur, a period of observation of 2 years are more is warranted if the patient is relatively asymptomatic. Gradual radiographic progression for 2 or more years, even without major symptoms or reduction in pulmonary function, indicates the need for a trial of corticosteroid treatment, especially in white patients where symptoms may lag behind the radiographic changes. Relapses as treatment is withdrawn are frequent, especially in African-American patients, who tend to have more severe and more prolonged disease than white patients. A minimum of 1 year of treatment is recommended unless no improvement is noted after 3 months. Continued low-dose prednisone at daily doses of 10-15 mg is helpful in preventing relapses and further progression of disease. Periodic attempts at tapering are justified. Repeated relapses may indicate the need for life-long treatment. When irreversible changes are present, especially in the presence of chronic fibrotic disease, changing goals of treatment to provide optimal supportive care may represent better management than having unrealistic expectations from increased corticosteroid dosage or the addition of other potentially toxic immunosuppressive agents. Many agents related to sarcoidosis require further research. The most important question facing sarcoid researchers today is etiology. It is difficult to design specific therapy when the fundamental causes and disease mechanisms are not established. Rather than being a single disease with a single cause, it is possible that a number of genetic factors and environmental or infectious agents may result in an immune response that is manifested as sarcoidosis. Understanding basic causal mechanisms may help explain the varied disease manifestations and aid in designing curative treatments. Such etiologic questions should be explored from both a basic science and an epidemiologic approach. Therapeutic trials of new drugs such as pentoxyfylline and possibly thalidomide are needed to address their potential as well as limitations of steroid therapy. Finally, for patients who have progressed to organ failure, the problems of sarcoid recurrence in transplanted tissue, increased allograft rejection, and long-term prognosis of solid organ transplants have yet to be resolved. (ABSTRACT TRUNCATED)