It's About Quality, Not Quantity: Qualitative FDG PET/CT Criteria for Therapy Response Assessment in Clinical Practice.

OBJECTIVE. FDG PET/CT has emerged as an effective tool for the timely accurate assessment of how tumors respond to therapy. To standardize interpretation and reporting, numerous response criteria have been developed. This article will review the evolution of these criteria along with their strengths and weaknesses. CONCLUSION. Several qualitative assessments applicable to common malignancies have been developed in recent years that solve many of the challenges faced by their quantitative predecessors. These are reviewed, and information is provided regarding individual treatment efficacy and prognosis.

Review of 18F-Fluciclovine PET for Detection of Recurrent Prostate Cancer.

Fluorine 18 (18F) fluciclovine (anti-1-amino-3-18F-fluorocyclobutane-1-carboxylic acid [FACBC]) is a radiolabeled amino acid analog that takes advantage of the amino acid transport upregulation in several types of cancer cells. FACBC is taken up to a greater extent in prostate cancer cells than in surrounding normal tissue, providing an opportunity for its use in cases of this common cancer. In 2016, the U.S. Food and Drug Administration found the accuracy of FACBC PET to be superior to that of other molecular imaging techniques and subsequently granted approval for its use in PET of recurrent prostate cancer. As FACBC is an 18F radiotracer, an on-site cyclotron is not required for its production. This feature enables the widespread clinical availability of this agent and, in turn, an opportunity for improved patient care. The clinical pharmacology and imaging features of FACBC are reviewed, and the role of this agent in the imaging of recurrent prostate cancer, within the context of research that supports its effectiveness, is discussed. The administration of and image acquisition facilitated by using FACBC, as compared with 18F fluorodeoxyglucose, which is more widely used, are described. In addition, the criteria for interpreting FACBC imaging findings are outlined, with emphasis on common causes of false-positive and false-negative findings. ©RSNA, 2019.

Optimizing the Diagnosis of Parkinsonian Syndromes With 123I-Ioflupane Brain SPECT.

OBJECTIVE. The purpose of this article is to provide a review of 123I-ioflupane SPECT in the evaluation of suspected parkinsonian syndromes (PSs). This collection of diseases presents frequent diagnostic challenges, even by movement disorder and dementia specialists. CONCLUSION. The 123I-ioflupane scan serves as an imaging biomarker of the status of presynaptic dopamine transporters (DATs) in the striatum. As a result of neuronal death, DATs are greatly reduced in patients with PS neurodegenerative disorders, whereas clinical mimics generally do not show striatal DAT loss. This provides a tremendous opportunity for 123I-ioflupane to aid in the accurate and timely diagnosis of these patients and optimize their management.

Intracranial Leptomeningeal Carcinomatosis from Breast Cancer Detected on 18F-FDG PET.

Leptomeningeal carcinomatosis is an uncommon manifestation of non-central nervous system (CNS) metastatic disease. Diagnosis, however, has important prognostic and treatment implications. We present a case in which intracranial leptomeningeal carcinomatosis from a primary breast cancer was detected with (18)F-FDG PET/CT, despite its low sensitivity for detection of CNS metastases from non-CNS primary tumors.

Future directions for monitoring treatment responses in breast cancer.

In the prior review, we outlined the current standard of care for monitoring treatment responses in breast cancer and discussed the many challenges associated with these strategies. We described the challenges faced in common clinical settings such as the adjuvant setting, neoadjuvant setting, and the metastatic setting. In this review, we will expand upon future directions meant to overcome several of these current challenges. We will also explore several new and promising methods under investigation to enhance how we monitor treatment responses in breast cancer. Furthermore, we will highlight several new technologies and techniques for monitoring breast cancer treatment in the adjuvant, neoadjuvant and metastatic setting.

Current approaches and challenges in monitoring treatment responses in breast cancer.

Monitoring response to treatment is a key element in the management of breast cancer that involves several different viewpoints from surgery, radiology, and medical oncology. In the adjuvant setting, appropriate surgical and pathological evaluation guides adjuvant treatment and follow up care focuses on detecting recurrent disease with the intention of improving long term survival. In the neoadjuvant setting, assessing response to chemotherapy prior to surgery to include evaluation for pathologic response can provide prognostic information to help guide follow up care. In the metastatic setting, for those undergoing treatment, it is crucial to determine responders versus non-responders in order to help guide treatment decisions. In this review, we present the current guidelines for monitoring treatment response in the adjuvant, neoadjuvant, and metastatic setting. In addition, we also discuss challenges that are faced in each setting.

Sarcoidlike reaction of neoplasia causing hypermetabolic thoracic adenopathy in setting of extrathoracic malignancy: report of two cases and a review of the differential diagnostic considerations.

The development of noncaseating granulomas in a patient with underlying malignancy and no symptoms or signs suggestive of systemic sarcoid is often referred to as a sarcoidlike reaction and is estimated to occur in a small but significant portion of cancer patients. The pathogenesis is poorly understood, but the entity is hypothesized to be an immune phenomenon representing a host defense mechanism against the spread of tumor cells. Sarcoidlike reactions can occur at any time from the time of diagnosis to several years afterward and may occur in lymph nodes draining a malignant tumor, in the tumor itself, and even in nonregional tissues. Like sarcoid, sarcoidlike reactions of neoplasia can demonstrate hypermetabolic lymph nodes on (18)F-FDG PET imaging and thus be readily confused with metastatic disease. We describe 2 cases of a sarcoidlike reaction of neoplasia presenting as hypermetabolic thoracic lymph nodes on (18)F-FDG PET/CT obtained for follow-up of extrathoracic malignancies: one a 73-y-old woman with a history of stage III head and neck squamous cell carcinoma and the other a 34-y-old woman with recurrent giant cell tumor of the sacrum. In both instances, the differential diagnosis for the finding of hypermetabolic thoracic lymph nodes included the possibility of a sarcoidlike reaction, though tissue sampling was pursued to exclude the more worrisome presence of metastatic disease or, less likely, a new primary malignancy. We review the topic of sarcoidlike reactions of neoplasia as well as the analytic approach to hypermetabolic mediastinal and hilar lymph nodes encountered on (18)F-FDG PET/CT.