This is the current release of the guideline.

This guideline updates a previous version: Mohammed TL, Chowdhry AA, Khan AR, Amorosa JK, Batra PV, Dyer DS, Gurney JW, Jeudy J, Kaiser L, MacMahon H, Raoof S, Vydareny KH, Expert Panel on Thoracic Imaging. ACR Appropriateness Criteria® screening for pulmonary metastases. [online publication]. Reston (VA): American College of Radiology (ACR); 2008. 7 p. [41 references]

The appropriateness criteria are reviewed biennially and updated by the panels as needed, depending on introduction of new and highly significant scientific evidence.

Pulmonary metastases

To evaluate the appropriateness of initial radiologic examinations for pulmonary metastases screening

Patients with extrathoracic malignancies (ETMs) with a probability of pulmonary metastatic disease

Utility of radiologic examinations in differential diagnosis

Literature Search Procedure

The Medline literature search is based on keywords provided by the topic author. The two general classes of keywords are those related to the condition (e.g., ankle pain, fever) and those that describe the diagnostic or therapeutic intervention of interest (e.g., mammography, MRI).

The search terms and parameters are manipulated to produce the most relevant, current evidence to address the American College of Radiology Appropriateness Criteria (ACR AC) topic being reviewed or developed. Combining the clinical conditions and diagnostic modalities or therapeutic procedures narrows the search to be relevant to the topic. Exploding the term "diagnostic imaging" captures relevant results for diagnostic topics.

The following criteria/limits are used in the searches.

1. Articles that have abstracts available and are concerned with humans.
2. Restrict the search to the year prior to the last topic update or in some cases the author of the topic may specify which year range to use in the search. For new topics, the year range is restricted to the last 5 years unless the topic author provides other instructions.
3. May restrict the search to Adults only or Pediatrics only.
4. Articles consisting of only summaries or case reports are often excluded from final results.

The search strategy may be revised to improve the output as needed.

The total number of source documents identified as the result of the literature search is not known.

Strength of Evidence Key

Category 1 - The conclusions of the study are valid and strongly supported by study design, analysis, and results.

Category 2 - The conclusions of the study are likely valid, but study design does not permit certainty.

Category 3 - The conclusions of the study may be valid, but the evidence supporting the conclusions is inconclusive or equivocal.

Category 4 - The conclusions of the study may not be valid because the evidence may not be reliable given the study design or analysis.

The topic author drafts or revises the narrative text summarizing the evidence found in the literature. American College of Radiology (ACR) staff draft an evidence table based on the analysis of the selected literature. These tables rate the strength of the evidence for all articles included in the narrative text.

The expert panel reviews the narrative text, evidence table, and the supporting literature for each of the topic-variant combinations and assigns an appropriateness rating for each procedure listed in the table. Each individual panel member forms his/her own opinion based on his/her interpretation of the available evidence.

More information about the evidence table development process can be found in the ACR Appropriateness Criteria® Evidence Table Development document (see the "Availability of Companion Documents" field).

Modified Delphi Technique

The appropriateness ratings for each of the procedures included in the Appropriate Criteria topics are determined using a modified Delphi methodology. A series of surveys are conducted to elicit each panelist's expert interpretation of the evidence, based on the available data, regarding the appropriateness of an imaging or therapeutic procedure for a specific clinical scenario. American College of Radiology (ACR) staff distributes surveys to the panelists along with the evidence table and narrative. Each panelist interprets the available evidence and rates each procedure. The surveys are completed by panelists without consulting other panelists. The ratings are a scale between 1 and 9, which is further divided into three categories: 1, 2, or 3 is defined as "usually not appropriate"; 4, 5, or 6 is defined as "may be appropriate"; and 7, 8, or 9 is defined as "usually appropriate." Each panel member assigns one rating for each procedure per survey round. The surveys are collected and the results are tabulated, de-identified and redistributed after each round. A maximum of three rounds are conducted. The modified Delphi technique enables each panelist to express individual interpretations of the evidence and his or her expert opinion without excessive bias from fellow panelists in a simple, standardized and economical process.

Consensus among the panel members must be achieved to determine the final rating for each procedure. Consensus is defined as eighty percent (80%) agreement within a rating category. The final rating is determined by the median of all the ratings once consensus has been reached. Up to three rating rounds are conducted to achieve consensus.

If consensus is not reached, the panel is convened by conference call. The strengths and weaknesses of each imaging procedure that has not reached consensus are discussed and a final rating is proposed. If the panelists on the call agree, the rating is accepted as the panel's consensus. The document is circulated to all the panelists to make the final determination. If consensus cannot be reached on the call or when the document is circulated, "No consensus" appears in the rating column and the reasons for this decision are added to the comment sections.

Not applicable

The guideline developers reviewed published cost analyses.

Criteria developed by the Expert Panels are reviewed by the American College of Radiology (ACR) Committee on Appropriateness Criteria.

ACR Appropriateness Criteria®

Clinical Condition: Screening for Pulmonary Metastases

Variant 1: Primary malignancy: bone and soft-tissue sarcoma.

Radiologic Procedure	Rating	Comments	RRL*
CT chest without contrast	9	Initial evaluation or surveillance.
X-ray chest	9	If performed as a baseline.
FDG-PET whole body	5	Attenuation correction by radionuclide methods or, more commonly, with CT, is considered part of the examination.
MRI chest with or without contrast	2		O
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 2: Primary malignancy: renal cell carcinoma.

Radiologic Procedure	Rating	Comments	RRL*
X-ray chest	8
CT chest without contrast	7	Depends on the stage of the disease.
MRI chest with or without contrast	2		O
FDG-PET whole body	1	Attenuation correction by radionuclide methods or, more commonly, with CT, is considered part of the examination.
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 3: Primary malignancy: testicular cancer.

Radiologic Procedure	Rating	Comments	RRL*
X-ray chest	8
CT chest without contrast	7	Recommended if abdominal disease is present.
MRI chest with or without contrast	3		O
FDG-PET whole body	3	Attenuation correction by radionuclide methods or, more commonly, with CT, is considered part of the examination.
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 4: Primary malignancy: malignant melanoma.

Radiologic Procedure	Rating	Comments	RRL*
X-ray chest	9	If performed as a baseline.
CT chest without contrast	8	Initial evaluation or surveillance.
FDG-PET whole body	5	Attenuation correction by radionuclide methods or, more commonly, with CT, is considered part of the examination.
MRI chest with or without contrast	2		O
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 5: Primary malignancy: head and neck carcinoma.

Radiologic Procedure	Rating	Comments	RRL*
X-ray chest	9	If performed as a baseline.
CT chest without contrast	9	Initial evaluation or surveillance.
FDG-PET whole body	5	Attenuation correction by radionuclide methods or, more commonly, with CT, is considered part of the examination.
MRI chest with or without contrast	2		O
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Summary of Literature Review

The incidence of pulmonary metastatic disease in patients who have died of an extrathoracic malignancy (ETM) is reported as 20% to 54%. The indications for chest radiography, computed tomography (CT), magnetic resonance imaging (MRI), scintigraphic imaging, and positron emission tomography/computed tomography (PET/CT) have been discussed in the literature. There have been improvements in CT imaging quality and scan time, as well as advances in the field of nuclear medicine and MRI. In particular, there has been widespread use of PET/CT for evaluating patients with metastatic pulmonary disease, especially in patients with primary head and neck tumors.

In determining the specific imaging modality that should be used, authors conclude that several factors should be taken into consideration: 1) the biological behavior of the tumor, 2) the sensitivity and specificity of the imaging modality, 3) radiation dose, and 4) cost-effectiveness. The relative indications for chest radiography, CT, MRI, and scintigraphy have been evaluated for various primary malignancies. Detection of pulmonary nodules, lymphangitic spread, endobronchial lesions, intravascular metastatic pulmonary disease, nodal disease, and chest wall lesions have all been discussed in the literature.

Chest Radiography

It is generally accepted that chest radiography, with posteroanterior (PA) and lateral views, should be the initial imaging test in patients without known or suspected thoracic metastatic disease. If the chest radiograph demonstrates obvious multiple pulmonary nodules, further imaging beyond follow-up chest radiography may not be indicated unless biopsy is planned, or unless precise quantification of disease is required in the preoperative evaluation for metastasectomy or the assessment of response to systemic radiation therapy or chemotherapy.

Some authors have questioned the role of routine chest radiographs. In one study, a review of routine chest radiographs obtained in the evaluation of patients with breast cancer revealed that fewer than 0.93% of these radiographs demonstrated previously undiagnosed pulmonary metastases. In another study, 876 asymptomatic patients with localized cutaneous (stage I or intermediate thickness stage II) malignant melanoma had initial staging chest radiographs; 130 (15%) had "suspicious" findings, but on further follow-up, only 1 (0.1%) of these patients had a true-positive study for pulmonary metastasis. Another study analyzed the overall cost-effectiveness of chest radiographs in the life-long screening of patients with intermediate-thickness cutaneous melanoma. It was concluded that significant cost savings may be possible by decreasing the frequency of screening in the first 2 years and limiting screening to the first 5 to 10 years after diagnosis. Yet another study involving 23 patients with untreated primary head and neck tumors demonstrated that chest radiography by itself had a lower sensitivity of detecting pulmonary metastatic disease (67%) compared to PET/CT (100%). Patients with higher probability of pulmonary metastatic disease should be screened more frequently or with a more sensitive imaging modality such as CT. Additionally, it has been argued that the use of a chest radiograph by itself may cause increased anxiety in patients without known metastasis due to its high rate of false-positive findings.

Computed Tomography

Compared with chest radiography, CT is much more sensitive for detecting pulmonary nodules, because of its lack of superimposition and its high contrast resolution. Other abnormalities, such as lymphadenopathy, pleural involvement, chest wall lesions, endobronchial lesions, intravascular pulmonary involvement, or incidental findings in the upper abdomen, may also be revealed or better demonstrated. In patients with known ETM, chest CT is recommended if the initial chest radiograph reveals an apparent solitary pulmonary nodule or an equivocal finding. If the chest radiograph is negative, CT is recommended if the underlying ETM is one that has a high propensity for dissemination to the lungs, such as breast, renal cell, colon, and bladder carcinoma. As noted in the preceding section, CT is indicated even with multiple pulmonary nodules on the chest radiograph if biopsy or definitive treatment by metastasectomy or systemic therapy is planned.

It is now well known that spiral CT scanning is more sensitive than conventional CT, allowing the detection of a significantly larger number of nodules and also a larger number of small nodules <5 mm in diameter. With further developments in technology, it is likely that the sensitivity of CT scanning will continue to improve while the radiation dose associated with scanning may be lowered. Nevertheless, a few studies that have correlated CT findings with surgical or pathologic findings offer some sobering results. In a retrospective review, it was found that CT underestimated the surgical pathologic findings in 25% of cases. More thorough detection of metastatic nodules is possible at thoracotomy by means of manual palpation of the entire collapsed lung.

It has been suggested that the greater sensitivity of CT for detecting pulmonary nodules, as compared with chest radiography, is associated with diminished specificity. Nevertheless, it is increasingly recognized that even small pulmonary nodules may represent malignant lesions. In a series of patients undergoing video-assisted thoracoscopic resection of small (≤1 cm) pulmonary nodules, 28 malignant lesions were diagnosed in 27 patients with a history of previous malignancy; 23 lesions (84%) were malignant, including 15 metastases (54%) and eight new lung carcinomas (29%), and five nodules (18%) were benign. The specificity of CT in any given series depends on several variables: 1) the propensity of the underlying ETM to disseminate to the lungs; 2) the stage of the ETM; 3) selection factors for the study population; and 4) patient age, smoking history, history of prior treatment for the ETM, and likelihood of prior granulomatous disease. In addition, it has been reported that intraoperative palpation of the lungs is still warranted to detect metastatic lesions not detected by spiral CT. In one study, 22% (9/41) more malignant nodules were found intraoperatively than were detected by helical CT.

Computer-aided detection (CAD) for pulmonary metastatic disease has been adapted to chest CT from applications from mammography. Although these programs are in their developmental phases, it has been suggested that CAD can be used as a second look after the radiologist has completed reviewing the study. Nevertheless, these programs require more development and currently can only be used when there is limited breathing artifact and stable lung expansion. A recent study demonstrated that CAD detected 82.4% of known pulmonary nodules under ideal conditions. CAD is still in the experimental phase and currently has limited use in evaluating patients with pulmonary metastatic disease.

The utility of CT for evaluating intravascular pulmonary metastatic disease has also been described recently. Liver, kidney, stomach, and breast carcinoma as well as sarcomas have been reported to embolize to the pulmonary vasculature. Differentiation between metastatic disease and thromboembolic disease can be difficult. One study described morphological features such as tubular and beaded appearance to help distinguish between the two. With improvement of CT resolution, such intravascular metastatic disease will be more readily detectable.

More recently, it has been suggested that attenuation measurements of pulmonary nodules may help determine if a nodule represents a metastasis or a primary lung carcinoma. One study evaluated 39 pulmonary nodules in 36 patients with pulmonary metastases from renal cell carcinoma and 30 pulmonary nodules in 42 patients with primary lung carcinoma. They discovered that the mean attenuation value of metastatic pulmonary nodules from renal cell carcinoma was greater than that for primary lung carcinoma nodules. Therefore, attenuation measurements in patients with untreated disease may help the radiologist determine the origin of a nodule in patients with more than one primary cancer. Nevertheless, biopsy still remains the gold standard.

CT can be used not only to detect pulmonary metastatic disease but also to determine response to therapy. Patients can be evaluated by follow-up CT to determine if nodule size is decreasing or if there are any new pulmonary metastases. CT volumetry has been discussed in the literature and may prove to be a more accurate method for determining response to therapy, especially when there are small changes in tumor size.

Recommendations for the use of CT in detecting pulmonary metastases must be tailored for each ETM. Even for an individual ETM, however, it may still be difficult to arrive at a consensus for the optimal application of CT. Some guidelines for chest CT surveillance in a few common primary tumors, as determined from review of the recent literature, are summarized below.

Bone and Soft-tissue Sarcomas

Despite multiagent chemotherapy regimens and radical resection of the primary tumor, a large number of patients with bone and soft-tissue sarcomas will have relapse, manifested by dissemination of disease to the lungs as the first site of metastasis. One review of the published literature for osteosarcoma recommends aggressive surgical resection of synchronous and metachronous pulmonary metastases, even if multiple thoracotomies are required. These authors state that CT is the preferred study in the screening for such metastases, although up to twice as many lesions may be found at thoracotomy.

A more recent study on pediatric bone and soft-tissue sarcomas discusses the importance of recognizing that imaging features on CT are important in determining whether metastatic disease is present. In this review of 210 patients, 41.7% of patients who underwent biopsy or resection of a pulmonary nodule had metastasis. Those with three or more nodules, bilateral distribution of disease, and/or large nodule size were more likely to have metastasis. This study performed at St. Jude Children's Research Hospital stressed the importance of low-dose chest CT as the initial screening modality for children with bone and soft-tissue sarcomas because of its high sensitivity for detecting pulmonary nodules, the size and distribution of which are associated with outcome.

The presence of nodules, regardless of their size, has an impact on long-term survival in patients with soft-tissue sarcomas. In a recent study, 331 sarcoma patients were followed. Of these, 71 had small, indeterminate nodules detected on CT. Of these patients, 28% developed pulmonary metastatic disease, most (90%) in the area of the original indeterminate nodule.

Other authors, in a study of 5-year survival after pulmonary metastasectomy for soft-tissue sarcoma, determined through multivariate analysis that the number of nodules detected by preoperative CT has prognostic value, and they recommend routine use of CT. In another study of patients with high-grade soft-tissue sarcomas undergoing metastasectomy, a specific protocol for follow-up is described: routine chest radiographs and chest CT are performed for the first 5 years, with a radiograph obtained at each visit and chest CT performed every 3 months for the first year, every 4 months for the second year, every 6 months for the third year, and once yearly thereafter.

Renal Cell Carcinoma

Pulmonary metastases from renal cell carcinoma are seen in 25% to 30% of patients at the time of initial diagnosis, and in 30% to 50% of patients at a later time. In patients with metastases to the lungs, surgical resection may provide the only effective treatment, in light of the fact that 5-year survival rate is <5% for stage IV disease. Based on their own experience and a review of the literature, authors of one study recommended PA and lateral chest radiographs as an initial test. In patients with low-stage (T1) disease and a normal chest radiograph, CT is not necessary; if the chest radiograph demonstrates multiple nodules, CT is not necessary unless it is required as part of the protocol for systemic therapy. The authors proposed that indications for chest CT should include 1) a solitary pulmonary nodule on the chest radiograph; 2) symptoms suggestive of endobronchial metastasis; 3) extensive regional disease; and 4) presence of other extrathoracic metastases that might be amenable to resection. Other authors advocate a more aggressive approach, with biannual chest radiographs and chest CT examinations. They recommend that such surveillance be life-long, in view of the possibility of delayed recurrent pulmonary metastases.

Testicular Cancer

It was suggested in one study that the risk of intrathoracic metastases is correlated with the presence of abnormal findings on abdominal CT. In this study, 74 of 155 patients with seminomatous or nonseminomatous testicular germ cell tumors had both chest radiographs and chest CT scans concurrently at the time of initial staging. Findings were compared to those of patients having negative or abnormal abdominal CT scans. For the group of 42 patients with negative abdominal CT scans, results of chest CT did not increase the yield for diagnosis of metastases as compared with the chest radiograph; a 2.3% chest CT false-positive rate is in fact cited as a potential source of morbidity in the workup of patients. For the group of 32 patients with abnormal abdominal CT, however, chest CT allowed detection of pulmonary metastases not seen on the chest radiograph in 12.5% of cases. For initial staging workup, the authors therefore recommend chest radiographs for patients with a negative abdominal CT and chest CT for patients with an abnormal abdominal CT.

Malignant Melanoma

Recommendations for chest CT scanning in malignant melanoma appear to be largely determined by the stage of the primary tumor. One study retrospectively assessed the role of CT (neck, chest, abdomen, and pelvis) in detecting occult distant metastases in 89 asymptomatic patients with local-regional melanoma who had normal chest radiographs and serum lactate dehydrogenase levels. In only one case was there evidence of disease on chest CT that was not seen on the chest radiograph, and the authors concluded that chest CT may not be indicated. A large retrospective study of asymptomatic patients with stage III melanoma, assessing the role of CT (head, chest, abdomen, pelvis), suggests that chest CT should be used selectively in patients with cervical adenopathy. In a review of the role of surgical resection for melanoma metastatic to the lung, the researchers emphasized that metastasectomy may be the only potentially curative treatment modality in stage IV disease. While noting that metastasectomy is believed to improve survival in patients with one or two pulmonary nodules, the authors cautioned that the number of lesions should not be an absolute contraindication to surgery. They recommended that preoperative evaluation of patients for pulmonary metastasectomy should include not only chest CT to determine the number of nodules but also whole-body imaging to detect or exclude other extrapulmonary stage IV disease.

Head and Neck Carcinoma

Although the lungs are the most common site of distant metastases in squamous cell carcinoma (SCC) of the head and neck, there is no clear consensus as to the optimal imaging modality for surveillance. An issue of particular importance in this population is the known increased incidence (15% to 30%) of second primary malignancies, including neck, lung, and esophageal cancers. In one retrospective study, only two of 57 patients with head and neck SCC (stage not specified) had malignancy in the form of synchronous tumors identified on routine chest CT, and these lesions were also evident on chest radiographs. Other authors, however, have observed that chest CT demonstrates a high number of malignancies, including both pulmonary metastases and additional thoracic malignancies, in patients with advanced SCC. Among 93 patients undergoing chest CT at the time of initial presentation, during routine follow-up or at the time of local-regional neck recurrence, a total of 24 (25.8%) had identification of thoracic malignancy, including 14 (15%) with pulmonary metastases, five (5.4%) with lung carcinoma, and one (1.1%) with esophageal carcinoma. Except for two patients with initial stage I or II disease and local-regional neck recurrence, these patients all had stage III or IV disease.

Nevertheless, a more recent retrospective study performed in Austria demonstrated distant metastatic disease in 9 out of 163 (5.52%) patients with known head and neck squamous cell carcinoma. All of these patients had a screening chest CT that demonstrated pulmonary metastatic disease. Many of these patients had metastases to other organs as well. The authors concluded that the chest CT was the most important screening examination for evaluating metastatic disease in these patients.

Magnetic Resonance Imaging

MRI has been considered an alternative to CT for detecting pulmonary metastases, primarily because exposure to ionizing radiation is avoided, an issue of particular concern with young patients undergoing multiple follow-up examinations. Nevertheless, it is generally accepted that MRI does not currently have a role in screening of patients for pulmonary metastases. Motion-related artifacts, a lower spatial resolution than CT, and an inability to detect calcification within lesions all represent limitations of MRI. A recent study comparing turbo-spin echo MRI with spiral CT as a gold standard demonstrated a lower sensitivity for MRI in detecting pulmonary metastases; for 340 metastases identified on CT, the overall sensitivity of MRI was 84%, but for nodules <5 mm in diameter, sensitivity was only 36%. A more recent study comparing the nodule detection accuracy of various MRI sequences supports these results. The optimal sequence (triggered short time inversion recovery [STIR]) had a 72% sensitivity for nodule detection. These nodules were all previously seen on CT and were >5 mm in diameter.

Scintigraphy

The use of scintigraphy in conjunction with tumor-seeking agents may offer significant incremental information, enhancing the specificity of diagnosis, as compared with conventional morphologic imaging techniques. There are preliminary reports of results for a variety of scintigraphic techniques applied to a number of different malignancies, but the ultimate role of such imaging has yet to be established.

Imaging with fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) is increasingly being used in the staging of patients with bronchogenic carcinoma, not only to detect any nodal involvement but also to check for possible distant metastases. Its role in detecting pulmonary metastases from known ETM is well established. One study demonstrated the utility of FDG-PET in detecting occult extrapulmonary disease in patients with pulmonary metastatic melanoma. In particular, it was determined to be useful in excluding extrapulmonary metastatic melanoma prior to surgery, and the authors concluded that PET scanning should be used in patients with pulmonary metastatic melanoma prior to metastasectomy. Use of FDG-PET in the staging of malignant melanoma has also been investigated, but it is acknowledged that this technique has limited sensitivity for small pulmonary nodules and that false-positive results may occur because of inflammatory processes. The role of FDG-PET in staging head and neck tumors has also been discussed. Although it is helpful at times in detecting pulmonary metastasis, in one study of 86 patients, thoracic malignancy was suspected in 23 patients (27%) by uptake criteria. Of these suspicious lesions, 83% were found to be benign. Use of FDG-PET alone does not negate the need for spiral CT in evaluating pulmonary metastatic disease. A negative FDG-PET examination cannot exclude metastatic disease. This is thought to be due to small metastatic nodules.

The use of PET/CT versus CT alone for evaluating pulmonary metastatic disease has been discussed in the literature. PET/CT is commonly used for evaluating patients with primary head and neck tumors. In one study of 24 consecutive patients, there was no statistically significant difference between PET/CT and CT alone. However, this study is limited in that it only looked at nodules >1 cm in diameter. Currently, high-resolution chest CT is more sensitive in evaluating pulmonary metastasis than PET/CT, especially for metastasis measuring <1 cm in diameter. A more recent study evaluated the cost-effectiveness of using PET/CT to guide management of patients with suspected pulmonary metastatic disease from malignant melanoma. This Belgium study concluded that PET/CT was cost effective in that it could potentially avoid 20% of futile surgeries performed on patients who were thought to be free of metastasis. Although, one should keep in mind that this study was limited because it was based on a hypothetical model that relied on data published from other studies. At the present time, PET/CT is considered to be helpful in specific cases, but not as a screening tool for pulmonary metastasis.

Other radiopharmaceuticals have also been used in the past. In one older study, encouraging results were reported for the use of ^99mTc-methoxyisobutylisonitrile scintigraphy in 81 patients with a history of previously excised malignant melanoma. Such whole-body scanning correctly detected 92% of 74 metastatic lesions at various sites, including eight lung lesions ranging from 1.2 to 6.0 cm in size, two of which were not previously diagnosed. Use of an indium-111-labeled monoclonal antibody (CCR 086) for detecting colorectal metastases at various sites, including lung lesions as small as 1 cm, has been reported. Bone scintigraphy with single photon emission computed tomography (SPECT) can be useful in patients with osteosarcoma metastasis. Additionally, a study performed in 2009 evaluated a new synthetic peptide called FBZA (fluorobenzamide), which, when coupled to FDG, demonstrated uptake in melanin-producing tumors in animal models.

Summary

• Chest radiograph should be performed as a baseline in patients with primary neoplasms known to metastasize to the pulmonary system.
• In many cases, a chest CT without contrast should be performed.
• A chest CT should be performed as an initial evaluation for patients with bone and soft-tissue sarcoma, malignant melanoma, and head and neck carcinoma.
• In patients with primary renal cell or testicular carcinoma, chest CT should be performed based on the presence of metastatic disease elsewhere.

Abbreviations

• CT, computed tomography
• FDG-PET, fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography
• MRI, magnetic resonance imaging

Relative Radiation Level Designations

Relative Radiation Level*	Adult Effective Dose Estimate Range	Pediatric Effective Dose Estimate Range
O	0 mSv	0 mSv
	<0.1 mSv	<0.03 mSv
	0.1-1 mSv	0.03-0.3 mSv
	1-10 mSv	0.3-3 mSv
	10-30 mSv	3-10 mSv
	30-100 mSv	10-30 mSv
*RRL assignments for some of the examinations cannot be made, because the actual patient doses in these procedures vary as a function of a number of factors (e.g., region of the body exposed to ionizing radiation, the imaging guidance that is used). The RRLs for these examinations are designated as NS (not specified).

Algorithms were not developed from criteria guidelines.

The recommendations are based on analysis of the current literature and expert panel consensus.

Selection of appropriate radiologic imaging procedures for pulmonary metastases screening

The American College of Radiology (ACR) Committee on Appropriateness Criteria and its expert panels have developed criteria for determining appropriate imaging examinations for diagnosis and treatment of specified medical condition(s). These criteria are intended to guide radiologists, radiation oncologists, and referring physicians in making decisions regarding radiologic imaging and treatment. Generally, the complexity and severity of a patient's clinical condition should dictate the selection of appropriate imaging procedures or treatments. Only those examinations generally used for evaluation of the patient's condition are ranked. Other imaging studies necessary to evaluate other co-existent diseases or other medical consequences of this condition are not considered in this document. The availability of equipment or personnel may influence the selection of appropriate imaging procedures or treatments. Imaging techniques classified as investigational by the U.S. Food and Drug Administration (FDA) have not been considered in developing these criteria; however, study of new equipment and applications should be encouraged. The ultimate decision regarding the appropriateness of any specific radiologic examination or treatment must be made by the referring physician and radiologist in light of all the circumstances presented in an individual examination.

An implementation strategy was not provided.

Not applicable: The guideline was not adapted from another source.

The American College of Radiology (ACR) provided the funding and the resources for these ACR Appropriateness Criteria®.

Committee on Appropriateness Criteria, Expert Panel on Thoracic Imaging

Panel Members: Tan-Lucien H. Mohammed, MD (Panel Chair); Aqeel Chowdhry, MD (Research Author); Gautham P. Reddy, MD, MPH, (Panel Vice-Chair); Judith K. Amorosa, MD; Kathleen Brown, MD; Debra Sue Dyer, MD; Mark E. Ginsburg, MD; Darel E. Heitkamp, MD; Jean Jeudy, MD; Jacobo Kirsch, MD; Heber MacMahon, MB, BCh; J. Anthony Parker, MD, PhD; James G. Ravenel, MD; Anthony G. Saleh, MD; Rakesh D. Shah, MD

Not stated

This is the current release of the guideline.

This guideline updates a previous version: Mohammed TL, Chowdhry AA, Khan AR, Amorosa JK, Batra PV, Dyer DS, Gurney JW, Jeudy J, Kaiser L, MacMahon H, Raoof S, Vydareny KH, Expert Panel on Thoracic Imaging. ACR Appropriateness Criteria® screening for pulmonary metastases. [online publication]. Reston (VA): American College of Radiology (ACR); 2008. 7 p. [41 references]

The appropriateness criteria are reviewed biennially and updated by the panels as needed, depending on introduction of new and highly significant scientific evidence.

Electronic copies: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.

Print copies: Available from the American College of Radiology, 1891 Preston White Drive, Reston, VA 20191. Telephone: (703) 648-8900.

The following are available:

• ACR Appropriateness Criteria®. Overview. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.
• ACR Appropriateness Criteria®. Literature search process. Reston (VA): American College of Radiology; 1 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria®. Evidence table development. Reston (VA): American College of Radiology; 4 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria®. Radiation dose assessment introduction. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.

None available

This NGC summary was completed by ECRI Institute on April 30, 2007. This NGC summary was updated by ECRI Institute on June 1, 2010. This NGC summary was updated by ECRI Institute on August 24, 2011.

Instructions for downloading, use, and reproduction of the American College of Radiology (ACR) Appropriateness Criteria® may be found on the ACR Web site .