Search

PURPOSE: To develop a pretherapy PET/CT-based prediction model for treatment response to ibrutinib in lymphoma patients. MATERIALS AND METHODS: One hundred sixty-nine lymphoma patients with 2441 lesions were studied retrospectively. All eligible lymphomas on pretherapy (18)F-FDG PET images were contoured and segmented for radiomic analysis. Lesion- and patient-based responsiveness to ibrutinib were determined retrospectively using the Lugano classification. PET radiomic features were extracted. A radiomic model was built to predict ibrutinib response. The prognostic significance of the radiomic model was evaluated independently in a test cohort and compared with conventional PET metrics: maximum standard uptake value (SUV(max)), metabolic tumor volume (MTV), and total lesion glycolysis (TLG). RESULTS: The radiomic model had an area under the receiver operating characteristic curve (ROC AUC) of 0.860 (sensitivity, 92.9%, specificity, 81.4%; P < 0.001) for predicting response to ibrutinib, outperforming the SUV(max) (ROC AUC, 0.519; P = 0.823), MTV (ROC AUC, 0.579; P = 0.412), TLG (ROC AUC, 0.576; P = 0.199), and a composite model built using all three (ROC AUC, 0.562; P = 0.046). The radiomic model increased the probability of accurately predicting ibrutinib-responsive lesions from 84.8% (pretest) to 96.5% (posttest). At the patient level, the model’s performance (ROC AUC = 0.811; P = 0.007) was superior to that of conventional PET metrics. Furthermore, the radiomics model showed robustness when validated in treatment subgroups: first (ROC AUC, 0.916; P < 0.001) versus second or greater (ROC AUC, 0.842; P < 0.001) line of defense and single treatment (ROC AUC, 0.931; P < 0.001) versus multiple treatments (ROC AUC, 0.824; P < 0.001). CONCLUSIONS: We developed and validated a pretherapy PET-based radiomic model to predict response to treatment with ibrutinib in a diverse cohort of lymphoma patients.

Purpose The aim of this study was to investigate the imaging diagnostic performance of F-fluciclovine PET/CT and pelvic multiparametric MRI (mpMRI) for prostate cancer in the setting of rising PSA after initial treatment, with a focus on detection of recurrent and metastatic prostate cancer in the pelvis. Methods Patients with prostate cancer who had fluciclovine PET and pelvic mpMRI between October 2017 and October 2018 in our center were retrospectively reviewed. Patients were included if they had fluciclovine PET/CT and mpMRI within a 3-month interval. Patients were excluded if they had separate concurrent cancer or if the PSA were more than 2-fold difference with an absolute difference more than 1 ng/mL between the 2 image studies. For each eligible patient, we compared all abnormal lesions identified on either scan. The findings were verified by pathology or other imaging techniques within minimal 10-month clinical follow-up. Results A total of 129 patients with 129 paired tests were included in this study. Fluciclovine PET/CT and pelvic MRI had a high degree of concordance (121/129, 93.8%). The sensitivity, specificity, positive predictive value, and negative predictive value for fluciclovine PET/CT and mpMRI were 96.6%, 94.3%, 93.4%, and 97%, and 91.5%, 95.7%, 94.7%, and 93%, respectively. There were no statistical significant differences in diagnostic performance between the 2 imaging tests. Among the 8/129 discordant cases, although fluciclovine PET/CT provided definitive diagnosis when mpMRI was equivocal due to paramagnetic artifacts from fiducial markers and detected normal-sized regional lymph nodes, mpMRI detected subcentimeter periurethral recurrence and clarified physiological urinary artifacts that was not appreciated on fluciclovine PET/CT. Conclusions Our single-center study demonstrated that fluciclovine PET/CT has similar diagnostic performance with pelvic mpMRI in detecting recurrent/metastatic prostate disease in the pelvis in the setting of rising PSA after initial treatment. Moreover, fluciclovine PET/CT and mpMRI have different implications in different clinical scenario; each test has its own limitation and pitfalls, but can be complementary to each other.

Based on the recent publications, including large cohort retrospective study and prospective clinical trial data, we are commenting on the optimal methods on myocardial suppression in FDG PET/CT evaluation of patients with suspected cardiac sarcoidosis.

A 76-year-old man presented with recently diagnosed prostate adenocarcinoma, Gleason score of 4 + 4, and a Super bone scan with concurrent PSA of 1.7 ng/mL. Approximately 3.5 months later, an F-fluciclovine PET/CT was performed despite of a decreased PSA of 0.3 ng/mL. A Superscan fluciclovine PET/CT was identified, and bone metastasis were later confirmed at biopsy.

Determine if skeletal tumor burden on 18F-fluoride PET/CT (fluoride PET/CT) predicts the risk of bone marrow failure (BMF) after 223Ra dichloride therapy (223Ra).Forty-one metastatic prostate cancer patients (43-89 years old; mean, 71 ± 9 years.) underwent fluoride PET/CT prior to 223Ra. Bone marrow failure was the primary end point and was defined as (1) development of hematologic toxicity (World Health Organization grade 3 or 4) associated with no recovery after 6 weeks or (2) death due to BMF after the last 223Ra dose. Bone marrow failure was correlated to fluoride PET/CT skeletal tumor burden (TLF10 [total lesion on fluoride PET/CT with SUVmax of 10 or greater]), use of chemotherapy, serum hemoglobin concentration, serum ALP, and serum prostate-specific antigen.The number of 223Ra cycles ranged from 2 to 6 (mean, 5). Of the 41 patients, 16 developed BMF (G3 = 12; G4 = 4). A significantly increased risk of developing BMF was observed in patients with TLF10 of 12,000 or greater (hazard ratio [HR], 11.09; P0.0001), hemoglobin of less than 10 g/dL (HR, 7.35; P = 0.0002), and AP146 UI/L (HR, 4.52; P = 0.0100). Neither concomitant (HR, 0.91; P = 0.88) nor subsequent use of chemotherapy (HR, 0.14; P = 0.84) increased the risk of BMF, nor was prostate-specific antigen greater than 10 μg/L (HR, 0.90; P = 0.86). Moreover, in a multivariable analysis, TLF10 was the only independent predictor of BMF (HR, 6.66; P = 0.0237).223Ra was beneficial and reduced the risk of death even in patients with a high skeletal tumor burden. Fluoride PET/CT is able to determine which patients will benefit from 223Ra and which will develop BMF.

A 60-year-old man with lymphoma completed chemotherapy on October 21, 2016, with complete remission. He then received rituximab maintenance therapy. Since March 2017, he has had progressive fatigue, myalgias, rash, weight loss, diarrhea, and recurrent low-grade fever. Subsequent bone marrow biopsy and FDG PET/CT demonstrated no active lymphoma. An In-white blood cell scan showed abnormal tracer uptake on 20-hour postinjection, but not on 3-hour postinjection images, including innumerable skeleton muscle foci, multiple cutaneous foci, and persistent diffuse increased uptake in the lungs. Diagnosis of adult-onset Still disease was made accordingly. The patient's cytopenia was deemed a chemotherapy-related adverse effect.

Purpose: This article discusses the value of incidental thyroid uptake of fluorodeoxyglucose (FDG) on whole-body positron emission tomography (PET) scans performed in patients with cancer. This issue has been reported diversely in the literature. Materials and Methods: Whole-body PET scans of four patients with cancer (two of them women; age, 49 to 78 years) in whom focal thyroid uptake was visualized and subsequently correlated with thyroid carcinoma based on cytologic or histopathologic data were reviewed. The clinical outcomes of these patients were analyzed retrospectively. Maximum and average standardized uptake values (SUVs) of thyroid accumulation were recalculated in all patients. Results: Two of the four patients referred for FDG PET scans had lung adenocarcinomas, one had prostrate carcinoma, and one had an unknown primary tumor. Focal thyroid uptake was visualized, with maximum and average SUVs ranging from 3.7 and 2.3 to 53 and 34, respectively. These findings were correlated with cytologic (two patients) or histopathologic data (two patients) that indicated thyroid carcinoma. In two patients, their treatment was changed and total thyroidectomy was performed; in one of them the SUVs of the focal thyroid accumulation (maximum and average values of 7.9 and 4.8, respectively) were less than the cutoff values for thyroid cancer noted in the literature. The clinical condition of the other two patients did not permit additional investigation or treatment for thyroid carcinoma. Conclusion: Increased focal thyroid uptake on whole-body FDG PET scans should not be overlooked, even when it is not marked, and should prompt further investigation to rule out cancer.

Acute graft-versus-host disease (GVHD) usually involves the skin, gastrointestinal tract, and liver. A 47-year-old woman with fever of unknown origin was referred for a Ga-67 scan. The study showed diffuse uptake of Ga-67 throughout the skin. Subsequently, a skin biopsy confirmed the diagnosis of acute GVHD. The incidence, diagnosis, and pathophysiology of the dermatitis in acute GVHD are discussed.

Erdheim-Chester disease (ECD) is a rare form of systemic non-Langerhans cell histocytosis with an unknown specific etiology and pathogenesis. Symptoms and findings of the disease depend on the site and extent of involvement. We report the case of a 43-year-old man with ECD who presented wit

A 66-year-old man with prostate cancer and an increasing prostate-specific antigen level was referred to the authors' department to undergo a fluorine-18 fluorode-oxyglucose (F-18 FDG) whole-body PET scan to evaluate the extent of his disease. The coronal whole-body PET image showed intense F-18 FDG uptake below the heart in what appeared to be another heart below the diaphragm. When more anterior coronal and sagittal PET images were reviewed, it became clear that the uptake represented the fundus of the stomach. The patient had diffusely increased uptake throughout the stomach. He had a history of gastritis, which most likely was the cause for this unusual finding.

Diffuse Tl-201 uptake in the lungs could be because of cardiac, neoplastic, inflammatory, or interstitial lung disease. Examples from the different categories, differential diagnosis, and different patterns are presented. The authors discuss the different mechanisms of increased Tl-201 uptake in the lungs which vary according to the underlying pathology.

Total body I-131 scanning done on a 67-year-old woman with thyroid cancer revealed abnormal tracer uptake within the mid-thorax, thought to represent metastasis in the mediastinum or thoracic spine. Single-photon emission computed tomography images of the thorax showed contiguity between the thoracic uptake and the normal, physiologic uptake of radioiodine in the stomach, suggesting physiologic accumulation within a hiatal hernia. To confirm the alimentary tract location of the radioiodine, a study using orally administered Tc-99m SC in water was performed. The images were similar to the iodine images and revealed a pattern consistent with hiatal hernia. A hiatal hernia was also observed as an incidental finding on chest radiographs and an MRI. This case illustrates the potential for an abnormal anatomic configuration to mimic metastatic thyroid cancer and shows how SPECT and oral Tc-99m SC images may be useful in making this distinction.

Twenty patients with known primary untreated and recurrent bone and soft tissue tumors underwent thallium imaging and three-phase bone imaging in the same session. The ratio of thallium uptake in the tumor tissue to the contralateral normal tissue areas was compared with the same ratio for phase 1 (blood flow or arterial phase), phase 2 (blood pool), and phase 3 (delayed medroxy-diphosphonate, MDP, uptake). There was poor correlation between Tl uptake and phases 1 and 3 of the bone scan ratios; r = 0.37 and 0.46; P = 0.097 and 0.047, respectively. The thallium uptake ratios correlated well with blood pool ratios (phase 2) (r = 0.84 and P less than 0.01). In contrast to uptake into normal muscle, Tl-201 uptake into tumor is not highly dependent on blood flow alone and other factors predominate in determining its magnitude.

A 23-year-old patient with osteopetrosis had Tc-99m SC scintigraphy to evaluate the bone marrow stores and possible foci of extramedullary hematopoiesis. The bone marrow scan showed depleted bone marrow stores in the bones, but significant extramedullary foci of hematopoiesis in the liver, spleen, and pelvis. SPECT images of the bone marrow and x-ray CT images of the abdomen and pelvis accurately localized the extramedullary foci of hematopoiesis