The effect of lossy discrete cosine transform compression on subtle bone fractures.

Extensive research efforts have been devoted to the feasibility of picture archiving and communication systems (PACS) in recent years. The advantages of PACS are numerous but mainly include reduced cost and improvement in the operational efficiency of a PACS-based radiology department. In digital radiography, images are viewed either in hard-copy or soft-copy format. Usually, these images are subsequently compressed and archived for future evaluation. There are various methods used in image compression. In this study, computed radiography images showing subtle pediatric bone fractures were compressed with the lossy method of image compression after they had been initially evaluated on workstation monitors. These studies were subsequently evaluated by observers, who were unaware of the interpretations of these images before compression, to determine if they could detect similar abnormalities. Our conclusion is that there is no difference in the interpretation of soft-copy computed radiographic images before or after lossy 10:1 compression in studies of subtle pediatric bone fractures. This is a US government work. There are no restrictions on its use.

Gastric emptying. Comparison of anterior only and geometric mean correction methods employing static and dynamic imaging.

Dynamic (continuous) and static imaging techniques were compared in the analysis of gastric emptying patterns in 16 consecutive adult patients with normal gastric half-emptying times assessed by dynamic imaging for 90 minutes under a dual head camera allowing simultaneous anterior and posterior imaging. Gastric t1/2 values were calculated for each patient based on four different data analysis methods: geometric mean corrected dynamic data (GD), anterior alone dynamic data (AD), geometric mean corrected simulated static data (GS), and anterior alone simulated static data (AS). The mean t1/2 values were: GD = 63.8 minutes, AD = 72.1 minutes, GS = 65.3 minutes, and AS = 73.0 minutes. Both the geometric mean corrected methods had a statistically different t1/2 than either of the anterior methods. Lag phase measurements, defined as a 2% decrease in gastric activity were: GD = 7 minutes, AD = 19 minutes, GS = 6 minutes, and AS = 16 minutes. Dynamic and static geometric mean methods provide similar gastric t1/2 calculations that are statistically different than anterior alone methods, and the lag phase is much shorter using either of the geometric mean methods.

The effects of danazol on a patient with familial dysalbuminemic hyperthyroxinemia.

Familial dysalbuminemic hyperthyroxinemia, a syndrome involving an abnormal affinity of albumin for thyroxine, results in elevated total thyroxine and free thyroxine index levels but normal triiodothyronine resin uptake and thyroid-stimulating hormone levels. Danazol is a synthetic androgen that increases triiodothyronine resin uptake and decreases total thyroxine, secondary to a decrease in thyroid-binding globulin levels. A 35-year-old woman with familial dysalbuminemic hyperthyroxinemia who was given danazol, in whom nervousness, insomnia, and weight gain developed, is described. Thyroid tests performed after initiation of danazol therapy revealed an increase in triiodothyronine resin uptake, with persistently elevated total thyroxine and free thyroxine index levels, and normal thyroid-stimulating hormone levels. Once the danazol was withdrawn, the symptoms resolved, the triiodothyronine resin uptake returned to normal, and the thyroid-stimulating hormone remained normal. The effects of danazol on a patient with familial dysalbuminemic hyperthyroxinemia correlate well with the effects on normals, and the ultrasensitive thyroid-stimulating hormone was the most useful test in separating hyperthyroxinemia from hyperthyroidism.

Diffuse abdominal uptake of technetium-99m-methylene diphosphonate in a patient on continuous ambulatory dialysis during bone scintigraphy.

Extra-skeletal uptake of bone seeking radiopharmaceuticals has been documented by scintigraphy. We present a case of diffuse uptake of 99mTc-methylene diphosphonate (MDP) in the abdomen of a patient while undergoing continuous ambulatory peritoneal dialysis (CAPD) who had no symptoms or findings referable to the abdomen. We hypothesized that the 99mTc-MDP crossed the peritoneal membrane across a concentration gradient. An in-vitro simulation confirms that 99mTc-MDP will cross a semi-permeable membrane. Diffuse uptake of 99mTc-MDP may be a normal variant in patients on CAPD who have no signs or symptoms of peritonitis.

Familial dysalbuminemic hyperthyroxinemia associated with multinodular goiter and elevated radioiodine uptake. A case report.

Familial dysalbumenic hyperthyroxenemia characterized by elevations in serum total thyroxine (T4) and free-thyroxine index and normal free T4 and radioiodine uptake has been previously described. This syndrome is secondary to an autosomal dominant inheritance in which affected individuals are mistakenly diagnosed as thyrotoxic because of the elevation of serum levels of total T4 and free T4. The excess T4 level is caused by the presence of an abnormal serum protein that binds excess T4, thereby raising the level of total T4. The authors report the case of a patient with familial dysalbumenic hyperthyroxenemia who presented with superimposed multinodular goiter and an elevated 24-hour radioiodide uptake.