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The immunocompromised patient with an acute respiratory illness (ARI) may present with fever, chills, weight loss, cough, shortness of breath, or chest pain. The number of immunocompromised patients continues to rise with medical advances including solid organ and stem cell transplantation, chemotherapy, and immunomodulatory therapy, along with the continued presence of human immunodeficiency virus and acquired immunodeficiency syndrome. Given the myriad of pathogens that can infect immunocompromised individuals, identifying the specific organism or organisms causing the lung disease can be elusive. Moreover, immunocompromised patients often receive prophylactic or empiric antimicrobial therapy, further complicating diagnostic evaluation. Noninfectious causes for ARI should also be considered, including pulmonary edema, drug-induced lung disease, atelectasis, malignancy, radiation-induced lung disease, pulmonary hemorrhage, diffuse alveolar damage, organizing pneumonia, lung transplant rejection, and pulmonary thromboembolic disease. As many immunocompromised patients with ARI progress along a rapid and potentially fatal course, timely selection of appropriate imaging is of great importance in this setting. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking, or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Background: Not all patients with diffuse large B-cell lymphoma (DLBCL) are candidates for aggressive regimens. 90Y ibritumomab tiuxetan (90Y-IT), an anti-CD20 radionuclide-conjugated antibody, has demonstrated clinical efficacy in DLBCL with a favorable toxicity profile. Methods: This phase II trial investigated the overall response rate (ORR), event-free survival (EFS), overall survival (OS) and toxicity of treatment with 90Y-IT (0.4 or 0.3 mCi 90Y/kg based on platelets) followed by rituximab maintenance therapy in patients with DLBCL not candidates for transplant. Results: 25 patients were enrolled. At best response 8 patients obtained a complete response (CR) and 1 a partial response (ORR 36%). Median EFS was 2.5 months and OS 8.1 months. No patient who obtained CR later relapsed systemically. Two patients were free of disease at the 61- and 100-month follow-ups; 65% had grade 3/4 thrombocytopenia, but no significant bleeding was observed. Grade 3 nonhematologic toxicity occurred in 36%. Patients who had progressed through a rituximab-containing regimen responded poorly. Conclusion: The ORR of 36% with 90Y-IT as salvage therapy for DLBCL while inferior to more aggressive regimens is significant with acceptable toxicity. For a subset of patients not candidates for salvage with autologous transplant, this treatment strategy can produce a durable, long-lasting remission.

OBJECTIVE To determine if diffuse hepatic uptake (DHU) of radioactive iodine (I-131) following radioactive iodine treatment has prognostic implications in otherwise scan-negative patients. METHODS This is a retrospective review of patients treated for differentiated thyroid cancer (DTC) at Beth Israel Deaconess Medical Center between January 1990 and June 2006. This group included patients receiving therapy to ablate presumed remnant tissue, as well as treatment for persistent disease as measured by thyroglobulin or imaging. All patients included in the study had no remnant uptake and otherwise negative posttherapy scans. A total of 57 patients with 63 scans met these criteria. The scans were then scored for DHU on a scale of 0 to 5, with 0 being no uptake and 5 being intense uptake relative to background. RESULTS Sixteen of 63 treatments were remnant ablations. Ten of 57 patients had positive thyroglobulin antibodies. Average DHU was similar in the ablation and therapeutic groups (1.9 vs. 2.3, P = .3). There was no correlation with either I-131 dose or the presence of thyroglobulin antibodies. There was a difference for DHU in the rate of disease-free survival, (undetectable thyroglobulin and no clinical or radiographic evidence of metastasis); 50% of patients with hepatic uptake scores of 0-2 were disease-free compared to 15% with scores of 3-5 (P

Rib fracture is the most common thoracic injury, present in 10% of all traumatic injuries and almost 40% of patients who sustain severe nonpenetrating trauma. Although rib fractures can produce significant morbidity, the diagnosis of associated complications (such as pneumothorax, hemothorax, pulmonary contusion, atelectasis, flail chest, cardiovascular injury, and injuries to solid and hollow abdominal organs) may have a more significant clinical impact. When isolated, rib fractures have a relatively low morbidity and mortality, and failure to detect isolated rib fractures does not necessarily alter patient management or outcome in uncomplicated cases. A standard posteroanterior chest radiograph should be the initial, and often the only, imaging test required in patients with suspected rib fracture after minor trauma. Detailed radiographs of the ribs rarely add additional information that would change treatment, and, although other imaging tests (eg, computed tomography, bone scan) have increased sensitivity for detection of rib fractures, there are little data to support their use. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review process include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Extravasation of therapeutic 90 Y-ibritumomab tiuxetan can cause significant injury. Detection of extravasated 90Y using a g-camera for patients undergoing 90 Y-ibritumomab tiuxetan therapy is a challenge because of the inherently low efficiency of bremsstrahlung imaging and the interference of prompt and scattered photons from 111 In that are still present in the body at the time of 90 Y injection. We have configured a g-camera to image bremsstrahlung radiation from superficial 90 Y in the presence of 111In and evaluated the effectiveness using phantoms. Methods: Phantoms were constructed to contain 90 Y and 111 In with activity levels and with a geometry approximating conditions in a patient being scanned for evaluation of possible extravasation in the antecubital fossa. Imaging was performed using a camera equipped with medium-energy general-purpose (MEGP) and high-energy general-purpose (HEGP) collimators. Results: The contrast that developed between the patch representing extravasated solution and the background was comparable for MEGP and HEGP collimators. With MEGP collimators and 5-min acquisitions, a patch containing 8.3 MBq (220 mCi) distributed over an elliptic area of 7 · 11 cm was clearly discernable. Conclusion: With our experimental arrangement, the lower limit of detection is approximately 8 MBq. We calculate that an extravasation of this much 90 Y would result in an absorbed dose to the skin and subcutaneous tissue of 2.5 Gy, which is close to the threshold for skin damage. This technique is therefore sensitive enough to be of use in the clinic when extravasation of 90 Yi s suspected.

In order to appropriately manage patients with lung cancer, it is necessary to properly stage the tumor. The ACR Appropriateness Criteria is designed to provide an overview of the value of different imaging techniques in the non-invasive staging of lung cancer and allow for the rational selection of imaging studies to arrive at the appropriate clinical stage.

The aim of this study was to evaluate prospectively the effects of respiratory gating during FDG PET/CT on the determination of lesion size and the measurement of tracer uptake in patients with pulmonary nodules in a clinical setting.Eighteen patients with known pulmonary nodules (nine women, nine men; mean age, 61.4 years) underwent conventional FDG PET/CT and respiratory-gated PET acquisitions during their scheduled staging examinations. Maximum, minimum, and average standardized uptake values (SUVs) and lesion size and volume were determined with and without respiratory gating. The results were then compared using the two-tailed Student's t test and the nonparametric Wilcoxon's test to assess the effects of respiratory gating on PET acquisitions.Respiratory gating reduced the measured area of lung lesions by 15.5%, the axial dimension by 10.3%, and the volume by 44.5% (p = 0.014, p = 0.007, and p = 0.025, respectively). The lesion volumes in gated studies were closer to those assessed by standard CT (difference decreased by 126.6%, p = 0.025). Respiratory gating increased the measured maximum SUV by 22.4% and average SUV by 13.3% (p0.001 and p = 0.002).Our findings suggest that the use of PET respiratory gating in PET/CT results in lesion volumes closer to those assessed by CT and improved measurements of tracer uptake for lesions in the lungs.

A 30-year-old, HIV-positive man with a previous history of an atypical nasopharyngeal Burkitt lymphoma developed fluorodeoxyglucose (FDG) avidity on a routine FDG-positron emission tomography (PET)/computed tomography scan performed 10 months after the completion of all treatment. This new FDG-avid disease was in the area of his initial disease. Flow cytometric assessment of a fine needle aspiration showed a CD10-expressing B-cell population with kappa predominance. The corresponding cytology smears had large atypical lymphoid cells along with smaller lymphocytes and macrophages. Because of the patient's previous history of a CD10(+), high-grade B-cell lymphoma, the cytologic and flow cytometric findings were considered highly suspicious for a B-cell lymphoma. Because the differential diagnosis included a relapsed Burkitt lymphoma versus a second, unrelated lymphoma (the former with a dismal prognosis) it was deemed prudent to obtain more tissue via an open biopsy for confirmation of diagnosis and exact subclassification. An open biopsy, however, revealed a reactive lymph node with enlarged geographic follicles; no lymphoma was demonstrable and c-Myc studies were negative. The patient remains without evidence of disease. Retrospectively, the original flow cytometric assessment was believed to likely represent sampling of hyperplastic germinal centers with significantly expanded CD10(+) B cells. The FDG uptake and the kappa predominance further confounded the interpretation. This case illustrates the pitfalls of standard diagnostic techniques, including PET scanning, cytology, and flow cytometry, particularly in the setting of HIV. It further underscores the importance of adequate clinical correlation and a low threshold for performing open biopsies in such patients.

OBJECTIVE. Many of the functions necessary for imaging and analyzing nuclear medicine studies are not available on radiology PACS. Over the past 20 years, we have developed a user-friendly, easily installed software package for nuclear medicine study analysis, display, Web access, and database storage and an integrated display for fused PET/CT. We are making this software available as free shareware that can be used without a license on any PC. The software package was developed as a cooperative effort between house and attending staff and our nuclear medicine programmer. Particular emphasis was put on making functions intuitive and user friendly.CONCLUSION. A shareware nuclear medicine PACS software package including a display for fused PET/CT studies has been developed, extensively clinically tested, and is freely available on the Internet.

Dyspnea, described as breathlessness or shortness of breath, is usually caused by cardiopulmonary disease. The role of imaging in chronic dyspnea (>1 mo in duration) with suspected pulmonary origin is reviewed as suggested by the American College of Radiology Appropriateness Criteria Expert Panel on Thoracic Imaging. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Background We investigated the relationship of stress technetium 99m sestamibi lung uptake with rest thallium 201 lung uptake and with indices of left ventricular (LV) dysfunction and severity of coronary artery disease (CAD) in patients with known or suspected CAD undergoing stress testing and cardiac catheterization. Stress Tc-99m sestamibi lung uptake and both stress and rest Tl-201 lung uptake are associated with LV dysfunction and extent of CAD. Although the mechanism of lung uptake is thought to be similar for the two isotopes, their physiologic characteristics are different. No direct comparison of lung uptake for the two isotopes has been reported.