FDG SPECT in patients with lung masses.

STUDY OBJECTIVES: To determine whether 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) single-photon emission CT (SPECT) is useful in characterizing pulmonary masses. DESIGN: Scans were prospectively acquired and interpreted. Interpretations were performed with CT or chest radiograph but interpreters were blinded to eventual diagnosis. SETTING: University hospital practice and affiliated Veterans Administration medical center. PATIENTS OR PARTICIPANTS: Forty patients participated as part of an institutional review board-approved research protocol, and informed consent was obtained in all. Eight additional patient scans were acquired as part of their clinical evaluation for pulmonary mass. MEASUREMENTS AND RESULTS: There were 26 malignant lesions (12 were 1 to 2 cm in size, the rest were larger) and 17 benign lesions (3 were < 1 cm in size, 9 were 1 to 2 cm in size, and 5 were larger). Averaged sensitivity, specificity, positive predictive value, and negative predictive value were, respectively, 50% (12 of 24), 94% (17 of 18), 92% (12 of 13), and 59% (17 of 29) for lesions 1 to 2 cm in size, 100% (28 of 28), 90% (9 of 10), 97% (28 of 29), and 100% (9 of 9) for lesions > 2 cm in size. There was good correlation between readers (p < 0.0001). CONCLUSION: FDG SPECT is useful in characterizing pulmonary masses > 2 cm in size and appears to be equivalent to positron emission tomography for these lesions. Although currently clinically suboptimal for characterizing lesions < or = 2 cm in size, FDG SPECT appears to be better than current anatomic imaging methods. In addition, the positive predictive value of FDG SPECT for small lesions is also high (92%), and this technique appears potentially useful in the subset of patients in whom a positive result would alter clinical diagnostic pathways or care.

Evaluation of a training program for improving adherence promotion skills.

A workshop for improving the adherence counseling skills of health professionals was developed and evaluated. Target audiences have included medical students, nursing students, dietetic interns, and practising nurses and dietitians. Four categories of skills are taught: relationship building, interviewing, problem diagnosis, and behavioral intervention. Teaching methods include faculty demonstration, participant rehearsal, and group and individual feedback. The Adherence Promotion Training (APT) workshop has been offered as a 3- to 5-day intensive course and as a semester-long elective. A reliable coding system was developed to assess these skills from videotaped provider-patient interactions. A standardized patient task was given to 60 subjects before and after participation in the adherence counseling skills workshop. Videotapes were coded by trained raters, who were masked to whether the tape came from before or after the workshop. Significant short-term improvements were observed in all four core skills. This uncontrolled evaluation suggests that the Adherence Promotion Training program is a promising way to enhance the ability of health professionals to care for nonadherent patients.

Volume changes during contraction of isolated frog muscle fibers.

A microscope objective and electronic imaging system were used to determine how isolated frog skeletal muscle fibers adjust their volume during an isometric tetanus. Cross-sectional area and volume of the middle third of a fiber increased rapidly with the development of active tension, which indicates that contraction produced components of force perpendicular to the long axis. The extreme ends are known to shorten whether or not the middle of a fiber is isometric or stretched. Shortening of the ends may shift water towards the middle, which could account for the volume changes we observed. The cytoskeletal matrices of muscle evidently adjust rapidly during contraction to maintain a dynamic equilibrium between the axial and radial forces that stabilize the whole cell. The Z disks have been shown to expand during active, but not passive, tension development. Z disks might be the elastic elements of the muscle cytoskeleton primarily involved in rapid balancing of the radial components of active force.

Nonuniform volume changes during muscle contraction.

We measured dynamic changes in volume during contraction of live, intact frog skeletal muscle fibers through a high-speed, intensified, digital-imaging microscope. Optical cross-sections along the axis of resting cells were scanned and compared with sections during the plateau of isometric tetanic contractions. Contraction caused an increase in volume of the central third of a cell when axial force was maximum and constant and the central segment was stationary or lengthened slightly. But changes were unequal along a cell and not predicted by a cell's resting area or shape (circularity). Rapid local adjustments in the cytoskeletal evidently keep forces in equilibrium during contraction of living skeletal muscle. These results also show that optical signals may be distorted by nonuniform volume changes during contraction.