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R Staron

Publications and source records attributed to R Staron.

7 recordsLinked to original sources

Energy-rich phosphates in slow and fast human skeletal muscle.

We investigated the relationship between energy-rich phosphate content and muscle fiber-type composition in human skeletal muscle using a combination of 31P-nuclear magnetic resonance spectroscopy (NMR), histochemical, and biochemical analyses of muscle biopsies. Localized 31P spectra were collected simultaneously from the predominantly slow-twitch soleus muscle and the mixed (fast-twitch and slow-twitch) medial and lateral gastrocnemius muscles, using B1-insensitive Hadamard Spectroscopic Imaging. Biopsy samples were taken from the soleus and lateral gastrocnemius muscles before NMR investigation and analyzed for fiber type composition and succinic dehydrogenase (SDH) activity. Fiber-type composition was determined based both on myofibrillar actomyosin ATPase activity combined with cross-sectional area and on myosin heavy-chain composition. Localized spectroscopy demonstrated a significantly (P < 0.001) higher P(i)/phosphocreatine ratio in the soleus muscle (0.15 +/- 0.01) compared with the medial (0.12 +/- 0.01) and lateral (0.10 +/- 0.0) gastrocnemius. However, in vitro analysis of muscle biopsies showed only a moderate relationship between the basal phosphate content and myofibrillar actomyosin ATPase-based fiber-type composition and SDH activity, respectively.

Adolescent↗

MR imaging: its role in detecting occult fractures.

Magnetic resonance (MR) studies were performed on 30 consecutive patients who continued to be symptomatic despite negative or inconclusive findings on radiographs and other imaging studies including radionuclide bone scans, computed tomography, and/or polytomography. There were 9 men and 21 women, 20-92 years old (mean age 63 years) whose MR studies were done 3-72 h after frank trauma in 22 cases and in another 8 after 1-4 weeks of increasing pain subsequently attributed to trauma or unaccustomed effort. MR studies were performed using 0.5-T (Phillips) or 1.5-T (Phillips, GE) superconductive magnets. Results indicated that: (1) MR images allowed identification of acute fractures in an emergency room setting, as well as subtle subacute or chronic fractures in the context of strong clinical suspicions despite negative or inconclusive radiographs and other subsequently indecisive imaging studies. (2) MR imaging is the most sensitive way of documenting the earliest changes in traumatized osseous and soft tissue structures simultaneously.

Adult↗

Heterogeneous in vivo MR images of soft tissue tumors: guide to gross specimen sampling.

Twelve soft tissue tumors preoperatively studied with magnetic resonance (MR) imaging contained areas of inhomogeneous intralesional signal intensity. The pathologist's selection of biopsy sites from gross specimens was based on specific MR images selected by a radiologist and depended on close cooperation between the radiologist and pathologist. The histopathology so sampled, further depended on the lesion's size, careful gross specimen orientation, discrete sampling, and a specially developed Grid Analysis technique. Our initial experience indicates that (1) histology may vary within different and often neighboring sites of a single soft tissue lesion; (2) that such variability is common in soft tissue tumors; (3) that histological variability within different sites of a single lesion influences signal heterogeneity; and (4) that although differing MR signal intensities per se are not tissue specific, MR may enhance the histopathological accuracy of pathologists who can be directed to particular gross specimen sites by magnetic resonance images. To our knowledge such a specific, detailed effort has not been made.

Adult↗

Magnetic resonance grid analysis of soft tissue lesions.

Soft tissue tumors of seven patients were imaged with magnetic resonance imaging (MRI) prior to operative resection. In four cases, gross surgical specimen biopsy sites were broadly selected from areas of diverse signal intensity. A subsequently developed "grid analysis" technique, used in three additional patients, better localized differing zonal intensities within individual gross specimens. Further investigation of this technique is warranted, since MR images, when analyzed by means of a detailed grid technique, appear to enhance histologic diagnostic accuracy. Examination of larger segments of inhomogeneous soft tissue tumors is facilitated, while pathologists' sampling time is diminished.

Adult↗

MR imaging of displaced bucket-handle tear of the medial meniscus.

A bucket-handle tear of the meniscus is a vertical or oblique tear with longitudinal extension toward the anterior horn in which the inner fragment is frequently displaced toward the intercondylar notch with resultant mechanical locking of the knee joint. A precise MR diagnosis requires identification of the centrally displaced fragment because the peripheral nondisplaced component may have only a subtle truncated or foreshortened appearance that may escape detection. Eighteen consecutive cases of displaced bucket-handle tears of the medial meniscus diagnosed by MR had a characteristic low-signal band extending across the joint and projecting over the medial tibial eminence. The posterior portion was parallel and beneath the posterior cruciate ligament on both sagittal and coronal images. Arthroscopy confirmed the presence and location of the displaced fragment in all 18 cases. Awareness of this characteristic MR finding may increase the sensitivity of MR imaging in the diagnosis of bucket-handle tears of the medial meniscus.

Adolescent↗

MRI of postamputation neuromas.

Magnetic resonance imaging of 24 symptomatic lower limb amputations revealed that postamputation neuromas were easily diagnosed in above-the-knee amputees. Visualization of nerve trunks in below-the-knee amputees was difficult due to greater compactness of calf muscles. Neuromas on magnetic resonance imaging appeared ovoid or rounded and were usually heterogenous and isointense with muscle. Magnetic resonance imaging also showed additional causes of stump pain such as scar formation, fat in atrophied muscles, soft tissue abscesses, osteomyelitis, and hematomas.

Adult↗