Objective To evaluate the effectiveness of power Doppler ultrasonography (PDUS) for assessing inflammatory activity in the metacarpophalangeal (MCP) joints of patients with rheumatoid arthritis (RA), using dynamic magnetic resonance imaging (MRI) as a reference method. Methods PDUS and dynamic MRI were performed on 54 MCP joints of 15 patients with active RA and on 12 MCP joints of 3 healthy controls. PDUS was performed with a LOGIQ 500 unit by means of a 7–‐13‐MHz linear array transducer. Later the same day, MRI was performed with a 1.0T MR unit. A series of 24 coronal T1‐weighted images of the second through the fifth MCP joints was obtained, with intravenous injection of gadolinium diethylenetriaminepentaacetic acid after the fourth image (dynamic MRI). From the MR images, the rate of early synovial enhancement (RESE; defined as the relative enhancement per second during the first 55 seconds postinjection) was calculated and compared with the flow signal on PDUS, which was scored as present or absent. Results In RA patients, flow signal on PDUS was detected in 17 of 54 MCP joints examined. Postcontrast MR images revealed an RESE of ≥1.0%/second in 18 of 54 RA MCP joints. PDUS showed no flow in 47 of 48 MCP joints with an RESE of <1.0%/second and revealed flow in 16 of 18 MCP joints with an RESE of ≥1.0%/second. Using dynamic MRI as a reference, PDUS had a sensitivity of 88.8% and a specificity of 97.9%. Conclusion PDUS was reliable for assessing inflammatory activity in the MCP joints of RA patients, using dynamic MRI as the standard. PDUS and clinical assessment of joint swelling/tenderness were only weakly correlated.

The use of positron emitter-labeled compounds for somatostatin receptor imaging (SRI) has become attractive because of the prospect of improved spatial resolution, accelerated imaging procedures, and the ability to quantify tissue radioactivity concentrations. This paper provides results from first-in-humans use of 64 Cu-DOTATATE, an avidly binding somatostatin receptor ligand linked to a radioisotope with intermediate half-life and favorable positron energy (half-life, 12.7 h; maximum positron energy, 0.653 MeV). Methods: In a prospective setup, 14 patients with a history of neuroendocrine tumors underwent both PET/CT with 64 Cu-DOTATATE and SPECT/CT with our current routine imaging agent 111 In-diethylenetriaminepentaacetic acid-octreotide. After intravenous injection of 193-232 MBq of 64 Cu-DOTATATE, whole-body PET scans were acquired at 1 h (n 5 14), 3 h (n 5 12), and 24 h (n 5 5) after administration. Tissue radioactivity concentrations for normal organs and lesions were quantified, and standardized uptake values were calculated for the early (1 h) and delayed (3 h) scans. Using the data for 5 patients, we assessed the radiation dose with OLINDA/EXM software. Furthermore, the clinical performance of 64 Cu-DOTATATE with respect to lesion detection was compared with conventional SRI. Results: SRI with 64 Cu-DOTATATE produced images of excellent quality and high spatial resolution. Images were characterized by high and stable tumor-to-background ratios over an imaging time window of at least 3 h. Compared with conventional scintigraphy, 64 Cu-DOTATATE PET identified additional lesions in 6 of 14 patients (43%). In 5 patients, lesions were localized in organs and organ systems not previously known as metastatic sites, including the early-stage detection of a secondary neuroendocrine tumor in a patient with a known mutation in the multiple endocrine neoplasia type I gene. All major additional findings seen only on PET could be confirmed on the basis of a clinical follow-up interval of 18 mo. Calculated radiation dose estimates yielded an effective dose of 6.3 mSv for an injected activity of 200 MBq of 64 Cu-DOTATATE, with the liver being the organ with the highest absorbed radiation dose (0.16 mGy/MBq).Conclusion: This first-in-humans study supports the clinical use of 64 Cu-DOTATATE for SRI with excellent imaging quality, reduced radiation burden, and increased lesion detection rate when compared with 111 In-diethylenetriaminepentaacetic acid-octreotide.

A clinical adoption of integrated PET/MRI should entail the joint image display and interpretation of MR data, MR-based attenuation maps and uncorrected plus attenuation-corrected PET images in order to recognize potential pitfalls from MR-AC and to ensure clinically accurate image interpretation.