18 F-FDG PET/MR Refines Evaluation in Newly Diagnosed Metastatic Urethral Adenocarcinoma Abstract We described the clinical impact of 18F-FDG PET/MR in refining the evaluation of a 39-year-old female with newly diagnosed metastatic urethral adenocarcinoma. We detailed the diagnostic imaging workup focusing our attention on the CT, MR, and 18F-FDG PET/MR different findings. In this case, 18F-FDG PET/MR imaging evaluation resulted not only effective but also altered staging and spared additional invasive procedures in the assessment of a metastatic urethral adenocarcinoma. Combining a highly sensitive PET with the increase tissue resolution of MR (PET/MR) may improve abdominal and pelvic lesion detection outperforming PET/CT for this indication.

Value of the Filtration Fraction Assessed by Dynamic 99m Tc-Diethylenetriaminepentaacetic Acid Renal Scintigraphy After Angiotensin-Converting Enzyme Inhibition for the Diagnosis of Renovascular Hypertension Abstract Purpose This study aimed to determine the diagnostic value of the relative filtration fraction (RFF) assessed by dynamic 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) renal scintigraphy after angiotensin-converting enzyme (ACE) inhibition for renovascular hypertension (RVHT) diagnosis. Methods 99mTc-DTPA captopril renal scintigraphy performed in adolescents or adults (≥ 10 years) with suspected RVHT was retrospectively reviewed. The RFF of the affected kidney was qualitatively assessed as the relative glomerular filtration rate during the 2 to 3-min period compared with the relative perfusion during the first 60 s (qualitative RFF) and scored from 1 (definitely same) to 5 (definitely decreased). The quantitative RFF of the affected kidney was obtained by dividing the percentage of glomerular filtration rate by the percentage of renal perfusion. Results Overall, 173 patients (high probability, n = 15; and low probability, n = 158) were included based on conventional captopril renal scintigraphic criteria. An abnormal qualitative RFF was observed in 12 patients with high probability, and the diagnostic sensitivity was 80.0% (95% CI, 51.9–95.7). The RFF was normal in 152 patients with low probability, and the diagnostic specificity was 96.2% (95% CI, 91.9–98.6). The RFF was lower in patients with high probability than in those with low probability (0.79 ± 0.15 vs. 1.02 ± 0.11, P < 0.0001). Conclusions The RFF assessed by dynamic 99mTc-DTPA renal scintigraphy after ACE inhibition can detect patients with high probability for RVHT. The RFF after ACE inhibition might be a useful diagnostic criterion especially when baseline scintigraphy is not available for evaluating ACE inhibition-induced changes.

Predictive Value of Interim and End-of-Therapy 18F-FDG PET/CT in Patients with Follicular Lymphoma Abstract Purpose 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is the standard imaging modality for response evaluation in FDG-avid lymphoma, but the prognostic value is not established in follicular lymphoma (FL). This study investigated the prognostic value of Deauville 5-point scale (D5PS) from paired interim PET/CT (PETInterim) and end-of-induction therapy PET/CT (PETEOI) in patients with FL. Methods FL staging and response assessment PET/CT images from 2013 to 2015 were retrospectively reviewed. PETInterim was performed 3 or 4 cycles after chemotherapy and PETEOI after 6 or 8 cycles. D5PS scores of 1, 2, and 3 were considered as negative (−), and scores 4 and 5 were considered as positive (+). Statistical analysis was done using Cox regression analysis, Kaplan–Meier survival analysis, and the log-rank test. Results Thirty-three patients with set of baseline, interim, and end-of-induction therapy PET/CT studies were included. Ten patients (30.3%) had progression. The median progression-free survival (PFS) was 38.8 months (range 3.5–72.7 months). On PETInterim, 23 patients were negative and 10 were positive. On PETEOI scans, 29 patients were negative, and 4 were positive. On multivariate analysis, PETEOI(−) was associated with longer PFS. PETInterim(+) and PETEOI(+) patients had a significantly shorter PFS than PETInterim(−) patients (39.9 months, 95% confidence interval [CI] 23.0–56.9, versus 55.5 months, 95% CI 49.7–61.2, p = 0.005) and PETEOI(−) patients (14.2 months, 95% CI 8.5–19.8, versus 60.5 months, 95% CI 52.1–69.0, p < 0.001). Conclusion For patients with FL, PETInterim and PETEOI response is predictive of PFS, and PETEOI(+) is an independent prognostic factor for progression of FL.

Minimum Standardized Uptake Value from Quantitative Bone Single-Photon Emission Computed Tomography/Computed Tomography for Evaluation of Femoral Head Viability in Patients with Femoral Neck Fracture Abstract Purpose Bone single-photon emission computed tomography/computed tomography (SPECT/CT) has been widely used for evaluation of femoral head viability in patients with femoral neck fracture. The current study aimed to investigate utility of standardized uptake value (SUV) from quantitative bone SPECT/CT for assessment of femoral head viability. Methods From March 2015 to November 2018, quantitative bone SPECT/CT was performed in 9 patients with non-viable femoral head post femoral neck fracture and in 31 controls. Maximum (SUVmax), mean (SUVmean), and minimum standardized uptake values (SUVmin) were measured over femoral head and neck. Mann-Whitney U test with Bonferroni correction was used to compare SUVs of ipsilateral and contralateral femurs from femoral neck fracture patients with those of control femurs. Results As for femoral head viability, SUVmax and SUVmean were not significantly decreased in non-viable femoral heads compared to those in controls. Only the SUVmin was significantly reduced in non-viable femoral heads (mean ± standard deviation, 0.57 ± 0.38) than in controls (0.95 ± 0.26, p = 0.006) and contralateral femoral heads (1.36 ± 0.59, p = 0.008). The cutoff SUVmin of 0.61 (g/mL) yielded a sensitivity of 77.8% and specificity of 87.1% for detection of non-viable femoral heads (p = 0.006). Contralateral femoral necks of the femoral neck fracture patients showed significantly higher SUVmean and SUVmin (3.17 ± 1.20 and 1.64 ± 0.63) than those of controls (2.32 ± 0.53 and 1.04 ± 0.27; p = 0.021 and p = 0.002, respectively), which seemed to reflect weight bearing effect or metabolic derangement. Conclusions The non-viable femoral heads from the femoral neck fracture showed significantly reduced SUVmin. Quantitative bone SPECT/CT holds promise for objective evaluation of femoral head viability.

Measurement of Tumor Pressure and Strategies of Imaging Tumor Pressure for Radioimmunotherapy Abstract Tumor interstitial pressure is a fundamental feature of cancer biology. Elevation in tumor pressure affects the efficacy of cancer treatment and results in the heterogenous intratumoral distribution of drugs and macromolecules. Monoclonal antibodies (mAb) play a prominent role in cancer therapy and molecular nuclear imaging. Therapy using mAb labeled with radionuclides—also known as radioimmunotherapy (RIT)—is an effective form of cancer treatment. RIT is clinically effective for the treatment of lymphoma and other blood cancers; however, its clinical use for solid tumor was limited because their high interstitial pressure prevents mAb from penetrating into the tumor. This pressure can be decreased using anti-cancer drugs or additional external therapy. In this paper, we reviewed the intratumoral pressure using direct tumor-pressure measurement strategies, such as the wick-in-needle and pressure catheter transducer method, and indirect tumor-pressure measurement strategies via magnetic resonance.

The Correlation Between Tenosynovitis Pattern on Two-Phase Bone Scintigraphy and Clinical Manifestation in Patients with Suspected Rheumatoid Arthritis Abstract Purpose To investigate the correlation between the tenosynovitis pattern on two-phase bone scintigraphy (2P-BS) and clinical manifestation in patients with suspected rheumatoid arthritis (RA). Method 2P-BS including technetium–99m-methylene diphosphonate blood pool and bone phase imaging in 402 consecutive patients with clinically suspected RA were retrospectively reviewed. According to 2010 RA Classification Criteria, patients were grouped as RA and non-RA. Visual assessment of all fingers, toes, wrists, and ankles on 2P-BS was performed. Clinical suspected tenosynovitis was evaluated on physical examination. Rheumatoid factor, anti-cyclic citrullinated protein antibody, C-reactive protein, and estimated sedimentation rate were obtained. Radiographic findings were also used to define early and established arthritis. Results Tenosynovitis pattern was detected in 12.7% (51/402 patients) on 2P-BS. A total of 94.1% (48/51) were diagnosed as RA vs. 5.9% (3/51) as non-RA. Of the 48 RA patients with positive 2P-BS finding, 85.4% (41/48) had early arthritis and 14.6% (7/48) had established arthritis. On physical examination, tenosynovitis was suspected in 21.9% (88/402). A total of 56.8% (50/88) belonged to the RA group and 43.2% (38/88) to the non-RA group. The tenosynovitis pattern of 2P-BS and physical examination showed statistical difference and moderate agreement. The positive tenosynovitis pattern on 2P-BS represented up to 26.408 of odds ratio which was highest among the RA-associated factors. Conclusion Tenosynovitis pattern on 2P-BS was more commonly detected in the RA group and was more frequently associated with early arthritis pattern. Therefore, 2P-BS could give additional information for the detection of subclinical tenosynovitis in early or preclinical RA patients.

Theranostics Based on Liposome: Looking Back and Forward Abstract Liposome is one of the oldest yet most successful nanomedicine platforms. Doxil®, PEGylated liposome loaded with doxorubicin (DOX), was approved by the FDA in 1995 for the treatment of AIDS-related Kaposi’s sarcoma, and it was the first approval for nanomedicine. Since then, liposome-based therapeutics were approved for the treatment of various diseases and many clinical trials are underway. The success of the liposome-based therapeutics was due to following factors: (1) ease of synthesis, (2) biocompatibility, (3) the ability to load both hydrophilic and hydrophobic agents, and (4) long circulation property after application of polyethylene glycol (PEG). Recently, more functionalities are introduced to liposome platform, which are (1) in vivo imaging probes for optical, magnetic resonance imaging (MRI), positron emission tomography (PET), and single-photon emission computed tomography (SPECT), (2) pH and temperature-sensitive lipid moiety, and (3) novel agents for photodynamic and photothermal therapies (PDT, PTT). These conventional and newly tested advantages make the liposome to be one of the most promising nanoplatforms for theranostics.

Treatment Response Assessment of Skeletal Metastases in Prostate Cancer with 18 F-NaF PET/CT Abstract Purpose To determine the utility of 18F-sodium fluoride positron emission tomography-computed tomography (18F-NaF PET/CT) in the imaging assessment of therapy response in men with osseous-only metastatic prostate cancer. Methods In this Institutional Review Board–approved single institution retrospective investigation, we evaluated 21 18F-NaF PET/CT scans performed in 14 patients with osseous metastatic disease from prostate cancer and no evidence of locally recurrent or soft-tissue metastatic disease who received chemohormonal therapy. Imaging-based qualitative and semi-quantitative parameters were defined and compared with changes in serum PSA level. Results Qualitative and semi-quantitative image-based assessments demonstrated > 80% concordance with good correlation (SUVmax κ = 0.71, SUVavg κ = 0.62, SUVsum κ = 0.62). Moderate correlation (κ = 0.43) was found between SUVmax and PSA-based treatment response assessments. There was no statistically significant correlation between PSA-based disease progression and semi-quantitative parameters. Qualitative imaging assessment was moderately correlated (κ = 0.52) with PSA in distinguishing responders and non-responders. Conclusion 18F-NaF PET/CT is complementary to biochemical monitoring in patients with bone-only metastases from prostate cancer which can be helpful in subsequent treatment management decisions.

Utility of FDG-PET/CT for the Detection and Characterization of Sternal Wound Infection Following Sternotomy Abstract Purpose FDG-PET/CT has the potential to play an important role in the diagnosis of sternal wound infections (SWI). The purpose of this study was to analyze the diagnostic accuracy of FDG-PET/CT for SWI in patients following sternotomy. Methods We performed a single-center, retrospective analysis of patients who had undergone median sternotomy and FDG-PET/CT imaging. The gold standard consisted of positive bacterial culture and/or the presence of purulent material at surgery. Qualitative patterns of sternal FDG uptake, SUVmax, and associated CT findings were determined, and an imaging scoring system was developed. The diagnostic performances were studied in both the recent (≤ 6 months between sternotomy and imaging) and remote surgery phase (> 6 months). Results A total of 40 subjects were identified with 11 confirmed SWI cases. Consensus interpretation was associated with a sensitivity of 91% and specificity of 97%. Combination of uptake patterns yielded an AUC of 0.96 while use of SUVmax yielded an AUC of 0.82. Conclusions Results suggest that FDG-PET/CT may be useful for the diagnosis of SWI with optimal diagnostic accuracy achieved by identifying specific patterns of uptake. SUVmax can be helpful in assessing subjects with remote surgery, but its use is limited in the context of recent surgery. Further studies are required to confirm these results.

Pleuropericardial Cyst Mimicking a Metastasis of Differentiated Thyroid Carcinoma on Whole-Body Iodine-131 Scan: a Case Report Abstract Post-therapeutic whole-body scan (WBS) with I-131 has been widely used for the follow-up of patients with well-differentiated thyroid cancer (DTC). Although the sensitivity of WBS with I-131 in detection of functioning thyroid tissues is high, its specificity is low. So, a further evaluation is required in cases of unexpected findings. The purpose of the study was to demonstrate that awareness of the potential pitfalls of WBS in DTC, knowledge of physiology and characteristics of radioiodine uptake, and correlation with other imaging modalities are needed to avoid incorrect management of patients with DTC. This is a case report of a 49-year-old woman with an unexpected area of increased I-131 uptake in the posterior lower chest, which was finally diagnosed as a pleuropericardial cyst. Due to the false-positive uptake of I-131 in the chest, an accurate interpretation of the scintigraphic findings should be made.