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To determine and classify radiographically demonstrated variations in calcaneonavicular morphology and to estimate prevalence in a clinically relevant patient population.Retrospective review was performed of foot radiographs obtained during diagnostic evaluation of 460 consecutive patients who presented to the emergency department with acute foot pain. Variations in calcaneonavicular morphology depicted on the medial oblique view (obtained at a 45 degrees angle) were classified into four groups according to morphologic type (types 1-4), and the prevalence of each type was calculated. Chi2 analysis was used to compare the prevalence of each type in male patients and in female patients. One-way analyses of variance were used to compare mean ages of patients for each type and mean calcaneonavicular gaps for each type.The prevalence of morphologic types 1, 2, and 3 was 94.3%, 2.8%, and 2.8%, respectively. The combined prevalence of types 2 and 3 (calcaneonavicular coalitions produced by synchondrosis and syndesmosis, respectively) was 5.6% (95% CI: 3.5%, 7.8%). There were no patients with type 4 morphology (synostosis). The numbers of male patients and female patients with morphologic types 1-3 were approximately equal (P =.9), and there was no statistically significant correlation between any of these three morphologic types and patient age (P =.2). The calcaneonavicular gap was significantly narrower in types 2 and 3 than in type 1 (P =.01), which was characterized as the normal morphology.The general prevalence of calcaneonavicular coalition (synchondrosis and syndesmosis) may be greater than previously reported, but further research is needed to prove the validity of this hypothesis.

A young adult man with neurofibromatosis type 1 (NF1) presented with a several-month history of an increasingly painful mass in the posteroinferior region of the right thigh. Imaging studies (Figure) showed a relatively well-circumscribed mass, 15 cm in length and 7 cm in diameter, arising on a background of very extensive involvement of the peripheral nervous system by plexiform neurofibromas. A biopsy specimen of the mass showed a high-grade (World Health Organization grade IV) malignant peripheral nerve sheath tumor (MPNST). An above-knee amputation was subsequently performed and the MPNST (Figure, inset A) was found to arise in continuity with one of the many preexisting low-grade (World Health Organization grade I) plexiform neurofibromas (Figure, inset B shows an example of such in the leg). For approximately 3.5 years following surgery and radiotherapy, there was no evidence of local tumor recurrence. The patient then was seen with a large left-sided retroperitoneal mass that was histopathologically confirmed to also be an MPNST, possibly a metastasis from the original thigh tumor but more likely a de novo primary tumor. He subsequently underwent several major debulking surgeries, radiotherapy, and rounds of chemotherapy, including palliative doxorubicin, for increasingly disseminated metastatic disease. He died approximately 7 years after his initial presentation.

We investigated the dependence of 20 radiographic carpal measurements (carpal indices) on rotational positioning errors in posteroanterior and lateral radiographs. The measurements were made from "true perspective" digitally reconstructed radiographs created from computed tomography data. Most posteroanterior indices were not affected by rotation. Carpal height, carpal height ratio, revised carpal height ratio, capitate-radius distance, and carpal ulnar translocation were particularly robust. Lateral-view indices involving the scaphoid were the most sensitive to simulated malpositioning: radioscaphoid, scapholunate, and scaphocapitate angles were reduced from 58 degrees, 48 degrees, and 56 degrees at true lateral to 30 degrees, 24 degrees, and 34 degrees, respectively, at 20 degrees external rotation. Observers were unable to estimate the degree of malpositioning accurately in either view. Our results support use of the "scaphopisocapitate" criterion for assessing correct positioning in lateral plain radiographs.

Purpose We investigated the feasibility of using real-time sonography to measure muscle thickness. Clinically, this technique would be used to measure the thickness of human muscles in which intramuscular microstimulators have been implanted to treat or prevent disuse atrophy. Methods Porcine muscles were implanted with microstimulators and imaged with sonography, MRI, and CT to assess image artifacts created by the microstimulators and to design protocols for image alignment between methods. Sonography and MRI were then used to image the deltoid and supraspinatus muscles of 6 healthy human subjects. Results Microstimulators could be imaged with all 3 methods, producing only small imaging artifacts. Muscle-thickness measurements agreed well between methods, particularly when external markers were used to precisely align the imaging planes. The correlation coefficients for sonographic and MRI measurements were 0.96 for the supraspinatus and 0.97 for the deltoid muscle. Repeated sonographic measurements had a low coefficient of variation: 2.3% for the supraspinatus and 3.1% for the deltoid muscle. Conclusions Real-time sonography is a relatively simple and inexpensive method of accurately measuring muscle thickness as long as the operator adheres to a strict imaging protocol and avoids excessive pressure with the transducer. © 2001 John Wiley & Sons, Inc. J Clin Ultrasound 29:230–236, 2001.