Radiographic analysis of metatarsus primus elevatus: a preliminary study.

The authors investigated the effect of x-ray tube head angulation and central ray direction on the position of the first metatarsal relative to the second metatarsal in the lateral foot radiographic view. This preliminary study shows that these variables may influence the perception of metatarsus primus elevatus in the weightbearing lateral foot radiograph.

Clinical consequences of alterations in platelet transfusion dose: a prospective, randomized, double-blind trial.

BACKGROUND: The dose-response relationship for platelet transfusion has become increasingly important as the use of platelet transfusion has grown. STUDY DESIGN AND METHODS: One hundred fifty-eight prophylactic apheresis platelet transfusions were administered to 46 patients undergoing high-dose therapy followed by hematopoietic progenitor cell transplantation in a prospective, randomized, double-blind, multiple-crossover study. Transfusions were administered in pairs, differing only in platelet content. Each pair consisted of a lower-dose platelet component (LDP) and a higher-dose platelet component (HDP) administered in random order to the same patient. LDPs contained a mean of 3.1 x 10(11) platelets (range, 2.3-3.5 x 10(11)), and HDPs contained a mean of 5.0 x 10(11) platelets (range, 4.5-6.1 x 10(11)). Patients with active bleeding and those who were refractory to platelet transfusions were excluded. RESULTS: The mean posttransfusion platelet count increment with LDP was 17,010 per microL, and that with HDP was 31,057 per microL (p<0.0001). Only 37 percent of LDPs resulted in platelet count increments of at least 20,000 per microL, whereas 81 percent of HDPs resulted in increments above this level (p<0.0001). The mean transfusion-free interval with LDP was 2.16 days, whereas that with HDP was 3.03 days (p<0.01). Administration of LDPs was associated with a 39 to 82 percent increase in the relative risk (per day) of requiring subsequent platelet transfusions (p<0.0001). CONCLUSION: As compared to the administration of HDPs, the administration of LDPs for prophylactic transfusion in hematopoietic progenitor cell transplant patients results in a lower platelet count increment, a lower likelihood of obtaining a posttransfusion platelet increment >20,000 per microL, a shorter transfusion-free interval, and a greater relative risk per day of requiring additional transfusions.

Comparison of calculated and experimental NMR spectral broadening for lung tissue.

NMR lineshapes were calculated for a model of lung, and NMR proton spectra were measured for individual voxels in an excised inflated rat lung. NMR lines for parenchymal lung regions containing alveoli, alveolar ducts, and capillaries were calculated using a computer simulation of the NMR signal from a three-dimensional honeycomb-like structure, a collection of modified Wigner-Seitz cells. These cells were modified by rounding the corners and increasing the thickness of the boundaries to model various degrees of lung inflation and lung water. NMR lineshapes were also calculated for the central or nonparenchymal lung regions containing bronchi and large blood vessels. A comparison of theoretical lineshapes with those measured in individual voxels both in the parenchymal and in the central (largely nonparenchymal) regions in excised rat lungs at an inflation pressure of 30 cm of water shows excellent agreement. These results indicate that the NMR lineshape reflects the underlying lung geometry. This research constitutes the first calculations and measurements of NMR lineshapes in lung. The appendix describes a new method for calculating the magnetic field inside a weakly diamagnetic material of arbitrary shape placed in an otherwise uniform external magnetic field. This new method does not require either solution of simultaneous equations or evaluation of integral expressions.

1993 William J. Stickel Silver Award. Anatomical considerations of the peroneal tubercle.

Gross discrepancy and error regarding the identification and location of the peroneal tubercle have been found in the literature. Furthermore, the authors found no evidence of a repeatable measurement technique in applicable descriptions of this osteologic landmark. In accordance with interrater reliability procedures, the authors established repeatability of peroneal tubercle measurements. In conjunction with the instrumentation's accuracy and resolution, the investigators infer reliability for these measurements. To the best of the authors' knowledge, this study is the only one in which interrater reliability was established for the morphometric assessment of the peroneal tubercle and the retrotrochlear eminence. The results also reestablish the correct anatomical presentation of the retrotrochlear eminence and the peroneal tubercle along the lateral surface of the calcaneus.

Radiologic aspects of aging in the foot.

This article discusses technical and radiologic aspects that should be considered when evaluating the geriatric population. Potential errors and accidents will be reduced and the office will function more efficiently by advance preparation. The interpreter must be aware of anatomic variations that could potentially be misdiagnosed as a pathologic condition. Finally, the radiographic presentation of disease may differ from that presenting in younger age groups.

Rapid line scan technique for artifact-free images of moving objects.

Moving objects (e.g., heart, lung, chest wall, etc.) typically cause artifacts to appear in two-dimensional Fourier transform ("spin warp") images. The rapid line scan (RLS) technique is a simple inexpensive technique that can rapidly produce artifact-free images of moving objects, without requiring enormous magnetic field gradients or periodic motions. The basic concepts and potential industrial applications of the RLS technique are described.

Alveolar air-tissue interface and nuclear magnetic resonance behavior of lung.

Inflated lungs are characterized by a short nuclear magnetic resonance (NMR) free induction decay (rapid disappearance of NMR signal), likely due to internal (tissue-induced) magnetic field inhomogeneity produced by the alveolar air-tissue interface. This phenomenon can also be detected using temporally symmetric and asymmetric NMR spin-echo sequences; these sequences generate a pair of NMR images from which a difference signal (delta) is obtained (reflecting the signal from lung water experiencing the air-tissue interface effect). We measured delta in normal excised rat lungs at inflation pressures of 0-30 cmH2O for asymmetry times (a) of 1-6 ms. Delta was low in degassed lungs and increased markedly with alveolar opening when measured at a = 6 ms (delta 6 ms); delta 6 ms varied little during the rest of the inflation-deflation cycle. Delta 1 ms (a = 1 ms) did not vary significantly on inflation and deflation. Measurements of delta at a = 3 and 5 ms generally lay between those of delta 1 ms and delta 6 ms. These findings, which are consistent with theoretical predictions, suggest that measurements of delta at appropriate asymmetry times are particularly sensitive to alveolar opening and may provide a means of distinguishing alveolar recruitment from alveolar distension in the pressure-volume behavior of the lung.

A systematic approach for radiographically evaluating joint disease in the foot.

A methodic analysis of foot radiographs is valuable when evaluating for joint disease. The author presents a system that allows the interpreter to establish a list of expected differential diagnoses. This is especially useful when the arthritide does not present with its classic radiographic appearance.

The radiographic presentation of osteomyelitis in the foot.

Numerous authors have described the radiographic findings associated with osteomyelitis. Knowledge of these findings and their presentation radiographically may make diagnosis of this pathology quite simple. The challenge comes not in diagnosing osteomyelitis based on gross radiographic evidence; by this time, the disease has significantly progressed. The challenge is to be able to recognize early, subtle changes, and, in conjunction with clinical findings, to diagnose and treat the disease before classic radiographic evidence is demonstrated.

Radiographic anatomy of the first metatarsal.

Normal radiographic anatomy of the first metatarsal bone is established through cadaver dissection, examination of bone specimens, and radiography. Extra-articular and distal articular anatomical landmarks are identified with wire markers. Dorsoplantar, lateral, lateral oblique, and medial oblique radiographs of 15 osteologic sites are presented, including the articular margins of the first metatarsal head, the borders of the three diaphyseal surfaces, the origins of the metatarsophalangeal collateral and metatarsosesamoid suspensory ligaments, and the insertions of the first cuneiform-metatarsal joint ligaments and the tibialis anterior and peroneus longus tendons. The correlation of gross anatomy and radiographs is described.

Coexistent gout and rheumatoid arthritis.

Gout and rheumatoid arthritis are relatively common entities individually; however, the coexistence of these two conditions has been reported rarely in the literature. The authors present a case that was followed for 20 years. The patient was seen by the acknowledged internist and podiatrist. Criteria for the evaluation and diagnosis of each disease entity are discussed and correlated to the case reported. Various theories and research attempting to explain the negative coexistence of gout and rheumatoid arthritis are presented.