PET/CT Imaging in Treatment Planning and Surveillance of Sinonasal Neoplasms.

Sinonasal cancers are uncommon malignancies with a generally unfavorable prognosis, often presenting at an advanced stage. Their high rate of recurrence supports close imaging surveillance and the utilization of functional imaging techniques. Whole-body 18F-FDG PET/CT has very high sensitivity for the diagnosis of sinonasal malignancies and can also be used as a "metabolic biopsy" in the characterization of some of the more common subgroups of these tumors, though due to overlap in uptake, histological confirmation is still needed. For certain tumor types, radiotracers, such as 11C-choline, and radiolabeled somatostatin analogs, including 68Ga-DOTATATE/DOTATOC, have proven useful in treatment planning and surveillance. Although serial scans for posttreatment surveillance allow the detection of subclinical lesions, the optimal schedule and efficacy in terms of survival are yet to be determined. Pitfalls of 18F-FDG, such as post-surgical and post-radiotherapy crusting and inflammation, may cause false-positive hypermetabolism in the absence of relapse.

Grassroots Approach to Forming a Diversity, Equity, and Inclusion Committee in an Academic Radiology Department.

Radiology is among the medical specialties that have made the fewest gains in closing the gap in underrepresented minorities and women. Diversity, equity, and inclusion (DEI) initiatives are important for promoting healthy learning environments for trainees, health equity for patients, and equitable career development opportunities for employees, all of which contribute to innovation in today's competitive health care environment. DEI committees can self-organize or form from institutional directives. These committees can implement impactful projects in multiple domains in education, recruitment and retention, department culture, and health equity research. This article describes the formation of a grassroots DEI committee, key initiatives and strategies, and structures for accountability. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Repeatability of 68Ga-PSMA-HBED-CC PET/CT-Derived Total Molecular Tumor Volume.

Molecular tumor volume (MTV) is a parameter of interest in prostate cancer for assessing total disease burden on prostate-specific membrane antigen (PSMA) PET. Although software segmentation tools can delineate whole-body MTV, a necessary step toward meaningful monitoring of total tumor burden and treatment response through PET is establishing the repeatability of these metrics. The present study assessed the repeatability of total MTV and related metrics for 68Ga-PSMA-HBED-CC in prostate cancer. Methods: Eighteen patients from a prior repeatability study who underwent 2 test-retest PSMA PET/CT scans within a mean interval of 5 d were reanalyzed. Within-subject coefficient of variation and repeatability coefficients (RCs) were analyzed on a per-lesion and per-patient basis. For the per-lesion analysis, individual lesions were segmented for analysis by a single reader. For the per-patient analysis, subgroups of up to 10 lesions (single reader) and the total tumor volume per patient were segmented (independently by 2 readers). Image parameters were MTV, SUVmax, SUVpeak, SUVmean, total lesion PSMA, and the related metric PSMA quotient (which integrates lesion volume and PSMA avidity). Results: In total, 192 segmentations were analyzed for the per-lesion analysis and 1,662 segmentations for the per-patient analysis (combining the 2 readers and 2 scans). The RC of the MTV of single lesions was 77% (95% CI, 63%-96%). The RC improved to 33% after aggregation of up to 10 manually selected lesions into subgroups assessed per patient (95% CI, 25%-46%). The RC of the semiautomatic MTVtotal (the sum of all voxels in the whole-body total tumor segmentation per patient) was 35% (95% CI, 25%-50%), the Bland-Altman bias was -6.70 (95% CI, -14.32-0.93). Alternating readers between scans led to a comparable RC of 37% (95% CI, 28%-49%) for MTVtotal, meaning that the metric is robust between scanning sessions and between readers. Conclusion:68Ga-PSMA-HBED-CC PET-derived semiautomatic MTVtotal is repeatable and reader-independent, with a change of ±35% representing a true change in tumor volume. Volumetry of single manually selected lesions has considerably lower repeatability, and volumetry based on subgroups of these lesions, although showing acceptable repeatability, is less systematic. The semiautomatic analysis of MTVtotal used in this study offers an efficient and robust means of assessing response to therapy.

Potential for Increasing Uptake of Radiolabeled 68Ga-DOTATOC and 123I-MIBG in Patients with Midgut Neuroendocrine Tumors Using a Histone Deacetylase Inhibitor Vorinostat.

Background: Histone deacetylase (HDAC) inhibitors have been shown in preclinical studies to upregulate norepinephrine transporters in neuroblastoma and pheochromocytoma, and somatostatin receptors in pulmonary carcinoid, small cell lung cancer, and pancreatic neuroendocrine malignancies. This pilot imaging study in humans focuses on midgut neuroendocrine carcinoma metastatic to the liver, evaluating the effect of pretreatment with the HDAC inhibitor vorinostat on uptake of 123I-MIBG and 68Ga-DOTATOC. Materials and Methods: Multiple midgut neuroendocrine liver metastases in clinically stable subjects were imaged with 123I-MIBG and 68Ga-DOTATOC before and after a 4-d course of vorinostat. Scans were performed with strict attention to detail and timed about 1 month apart occurring just before monthly long-acting octreotide administrations. Uptake changes in tumor and normal liver parenchyma were assessed on positron emission computed tomography (PET/CT) with standardized uptake values and on single photon emission computed tomography (SPECT) with qualitative ratio images. Results: The experimental units were metastatic liver lesions within patients (n = 50). There was no significant difference in administered activity or uptake time between pairs of scans for either radiotracer. Statistically significant increase in maximum standardized uptake values (SUVmax) averaged over all lesions was noted on the 68Ga-DOTATOC PET scans (+11%, p < 0.01). SUVmax in normal liver showed no significant change (p = 0.12). There was no qualitative change in uptake of 123I-MIBG after vorinostat. Conclusions: In this pilot imaging study in patients with midgut neuroendocrine liver metastases, a short course of the HDAC inhibitor vorinostat induced a statistically significant increase in SUVmax on 68Ga-DOTATOC PET/computed tomography (CT) imaging in some hepatic neuroendocrine tumor metastases. There was no significant effect of vorinostat on tumor uptake of 123I-MIBG on SPECT/CT imaging. Given the pilot nature of this trial, the findings merit further investigation with a more rigorous protocol evaluating longer pretreatment and different dosages of vorinostat or other HDAC inhibitors, as well as effects on the therapeutic capability of 177Lu- or 90Y-somatostatin analogs.

Diagnostic Performance of 18F-DCFPyL-PET/CT in Men with Biochemically Recurrent Prostate Cancer: Results from the CONDOR Phase III, Multicenter Study.

PURPOSE: Current FDA-approved imaging modalities are inadequate for localizing prostate cancer biochemical recurrence (BCR). 18F-DCFPyL is a highly selective, small-molecule prostate-specific membrane antigen-targeted PET radiotracer. CONDOR was a prospective study designed to determine the performance of 18F-DCFPyL-PET/CT in patients with BCR and uninformative standard imaging. EXPERIMENTAL DESIGN: Men with rising PSA ≥0.2 ng/mL after prostatectomy or ≥2 ng/mL above nadir after radiotherapy were eligible. The primary endpoint was correct localization rate (CLR), defined as positive predictive value with an additional requirement of anatomic lesion colocalization between 18F-DCFPyL-PET/CT and a composite standard of truth (SOT). The SOT consisted of, in descending priority (i) histopathology, (ii) subsequent correlative imaging findings, or (iii) post-radiation PSA response. The trial was considered a success if the lower bound of the 95% confidence interval (CI) for CLR exceeded 20% for two of three 18F-DCFPyL-PET/CT readers. Secondary endpoints included change in intended management and safety. RESULTS: A total of 208 men with a median baseline PSA of 0.8 ng/mL (range: 0.2-98.4 ng/mL) underwent 18F-DCFPyL-PET/CT. The CLR was 84.8%-87.0% (lower bound of 95% CI: 77.8-80.4). A total of 63.9% of evaluable patients had a change in intended management after 18F-DCFPyL-PET/CT. The disease detection rate was 59% to 66% (at least one lesion detected per patient by 18F-DCFPyL-PET/CT by central readers). CONCLUSIONS: Performance of 18F-DCFPyL-PET/CT achieved the study's primary endpoint, demonstrating disease localization in the setting of negative standard imaging and providing clinically meaningful and actionable information. These data further support the utility of 18F-DCFPyL-PET/CT to localize disease in men with recurrent prostate cancer.See related commentary by True and Chen, p. 3512.

Quantitative Test-Retest Measurement of 68Ga-PSMA-HBED-CC in Tumor and Normal Tissue.

The PET radiotracer 68Ga-PSMA (prostate-specific membrane antigen)-HBED-CC (N,N'-bis [2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine-N,N'-diacetic acid) shows potential as an imaging biomarker for recurrent and metastatic prostate cancer. The purpose of this study was to determine the repeatability of 68Ga-PSMA-HBED-CC in a test-retest trial in subjects with metastatic prostate adenocarcinoma. Methods: Subjects with metastatic prostate cancer underwent 2 PET/CT scans with 68Ga-PSMA-HBED-CC within 14 d (mean, 6 ± 4 d). Lesions in bone, nodes, prostate/bed, and visceral organs, as well as representative normal tissues (salivary glands and spleen), were segmented separately by 2 readers. Absolute and percentage differences in SUVmax and SUVmean were calculated for all test-retest regions. Repeatability was assessed using percentage difference, within-subject coefficient of variation (wCV), repeatability coefficient (RC), and Bland-Altman analysis. Results: Eighteen subjects were evaluated, 16 of whom demonstrated local or metastatic disease on 68Ga-PSMA-HBED-CC PET/CT. In total, 136 lesions were segmented in bone (n = 99), nodes (n = 27), prostate/bed (n = 7), and viscera (n = 3). The wCV for SUVmax was 11.7% for bone lesions and 13.7% for nodes. The RC was ±32.5% SUVmax for bone lesions and ±37.9% SUVmax for nodal lesions, meaning 95% of the normal variability between 2 measurements will be within these numbers, so larger differences are likely attributable to true biologic changes in tumor rather than normal physiologic or measurement variability. wCV in the salivary glands and spleen was 8.9% and 10.7% SUVmean, respectively. Conclusion: Repeatability measurements for PET/CT test-retests with 68Ga-PSMA-HBED-CC showed a wCV of 12%-14% SUVmax and an RC of ±33%-38% SUVmax in bone and nodal lesions. These estimates are an important aspect of 68Ga-PSMA-HBED-CC as a quantitative imaging biomarker. These estimates are similar to those reported for 18F-FDG, suggesting that 68Ga-PSMA-HBED-CC PET/CT may be useful in monitoring response to therapy.

Comparative analysis of radioactive iodine versus thyroidectomy for definitive treatment of Graves disease.

BACKGROUND: Management of Graves disease includes antithyroid drugs, 131I therapy, or thyroidectomy. Our aim was to review our institutional experience with definitive treatments for Graves disease. METHODS: This was a retrospective review of patients undergoing 131I therapy (n = 295) or thyroidectomy (n = 103) for Graves disease (2003-2015). Demographic, clinical, pathology, and outcome data were collected from institutional databases. RESULTS: 131I therapy patients were older (39.1 years vs 33.4 years, P = .001). There was no difference in the presence of ophthalmopathy between groups. A larger proportion of children received thyroidectomy than 131I therapy (17.1% vs 9.2%, P = .026). The success rate of the first 131I therapy dose was 81.4%. Overall success rate, including additional doses, was 90.1%. Rapid turnover of iodine correlated with 131I therapy failure (58.3% rapid turnover failure vs 14.9% non-rapid turnover failure, P < .05). All surgical patients underwent total or near-total thyroidectomy. 131I therapy complications included worsening thyrotoxicosis (1%) and deteriorating orbitopathy (0.7%). Operative complications were higher than 131I therapy complications (P < .05) but were transient. There was no worsening orbitopathy or recurrent Graves disease among surgical patients. CONCLUSION: A higher proportion of pediatric Graves disease patients underwent thyroidectomy than 131I therapy. Rapid turnover suggested more effective initial management with operation than 131I therapy. Although transient operative complications were high, 131I therapy complications included worsening of Graves orbitopathy among those with pre-existing orbitopathy.

Radiologic manifestations of angioedema.

OBJECTIVES: The purpose of this pictorial review is to present imaging findings of angioedema involving the various organs. CONCLUSION: The role of imaging for patients with angioedema includes the evaluation of the upper airway for obstruction and the exclusion of other possible aetiologies, such as neoplastic or infectious processes. Glossomegaly is a common finding of head and neck angioedema. Angioedema may involve organ systems beyond the superficial regions and the head and neck including the gastrointestinal and genitourinary tracts. Angioedema of the visceral organs is often accompanied by adjacent fluid, and it is commonly diffuse or concentric but can also be multifocal and asymmetric. TEACHING POINTS: • The evaluation of the upper airway obstruction is important for head and neck angioedema. • Glossomegaly with decreased attenuation is common in head and neck angioedema. • Angioedema of the visceral organs can be multifocal and asymmetric. • Angioedema of the visceral organs is often accompanied by adjacent fluid. • It is important to include clinical and laboratory findings for the diagnosis of angioedema.