Biomedical subjects
Publications and source records attributed to R F Kilcoyne.
Flat foot, a major cause of foot pain and disability, may result from rupture of the tibialis posterior tendon. We describe 2 patients with rheumatoid arthritis who developed flat feet secondary to surgically confirmed tendon rupture, and we discuss the anatomy and diagnosis of this condition. In the second patient, we also present the results of tendon imaging with both magnetic resonance and ultrasound.
Ankylosing spondylitis patients who develop progressive spinal flexion may assume this posture to alleviate the pain of apophyseal arthritis. To examine this relationship, we scored injury to L4-L5 and L5-S1 apophyseal joints, as assessed by computed tomography, in 10 men with early ankylosing spondylitis. Both by the modified Schober test and by radiography of the lateral spine, impaired spinal motion correlated highly with evidence of apophyseal injury.
Skeletal effects of retinoids on the spine were studied in two clinical trials. In the first study, spinal radiographs of 96 patients who had been treated with isotretinoin for 4 to 9 months were reviewed. The average age of these patients was 25 years, and during treatment or within 2 1/2 years after the end of treatment, 26% of the patients showed progressive formation of small bony spurs consisting of tiny horizontal excrescences that arose at the anterior margin of one or more vertebral bodies adjacent to the intervertebral disk. In a second study, the radiographs of 241 patients with psoriasis who were treated continually for 1 to 2 years with acitretin were examined. Many of these patients had abnormal radiographs at the start of therapy. These preexisting conditions included psoriatic arthritis, degenerative arthritis, and diffuse idiopathic skeletal hyperostosis. Five percent of the patients showed progression of their abnormalities during the study. The difference in the rate of spur formation in the two groups may be due to multiple factors and not simply to retinoid therapy. Because of the extensive amount of preexisting disease in the psoriasis group compared with the relatively normal appearance of the spine in the isotretinoin group, the underlying disease process may be more important than the retinoid therapy. The development of the spinal spurs was not associated with specific clinical symptoms. Since there was no control group, it is unknown whether the spurs would have developed or progressed in the absence of retinoid therapy.
Single-energy and dual-energy quantitative computed tomography (CT) techniques were used to analyze test solutions that contained agar, K2HPO4, and isopropanol, which stimulated collagen, mineral, and fat, respectively. The impact of the use of peripheral and anthropomorphic (central) calibration phantoms was also studied. A 10% change in fat content was found to cause errors in the estimated bone mineral content of -10 mg/mL, -14 mg/mL, and -1 mg/mL for single-energy CT at 80 kVp, single-energy CT at 140 kVp, and dual-energy CT, respectively. In the K2HPO4 solutions, the addition of 50 mg/mL agar increased the estimated bone mineral content by 20-33 mg/mL for single-energy CT, and by 12-17 mg/mL for dual-energy CT. The best estimates were obtained with central calibration and dual-energy CT, but the estimates were still 14%-24% greater than the true values. Calibration samples that more accurately simulate actual spongiosa may reduce this source of error. Caution should be exercised in the use of quantitative CT under conditions in which either the bone marrow or collagen content is altered by disease or therapy.
Several techniques are now available for quantitation of bone mass, including total body calcium by neutron activation analysis (TBC), single and dual photon absorptiometry at the radius and spine, respectively (SPA and DPA), quantitative computed tomography of the spine (QCT), and cancellous bone volume from iliac crest bone biopsies. The aims of this study were to assess the correlation among these techniques and to determine if bone mass correlated with height loss or the severity of vertebral fractures in osteoporotic women. These measurements were performed in the same group of women (n = 122) with postmenopausal osteoporosis. TBC, SPA, DPA, and QCT correlated significantly with each other (r = 0.33-0.76). The correlation between QCT and DPA improved significantly (r = 0.33-0.57; P = 0.02) when integral QCT was used instead of the usual QCT of the central vertebra. The correlation was not improved by expressing DPA in different dimensions, but was improved by including normal women. Multiple linear regression analysis showed that TBC was predicted better using SPA, DPA, and QCT than by any single variable. Cancellous bone volume correlated weakly (r = 0.10-0.26) to the other measurements. Height loss and fracture index correlated significantly with each other (r = 0.66; P less than 0.001), but the correlations with bone mass measurements were weak (r = -0.09 to -0.47). For each patient, a bone mass index was defined using z scores from the SPA, DPA, QCT, and TBC measurements; this index correlated inversely with the fracture index (r = -0.29; P = 0.009). This correlation was not significant when controlled for age. Thus, bone mass measurements correlate moderately well with each other, but poorly with severity of fracture. Other factors in addition to low bone mass may be important in determining whether bone will fracture.
Fifty-three patients with 60 symptomatic shoulders underwent shoulder sonography for recurrent postoperative symptoms after either acromioplasty (10 shoulders) or repair of a full-thickness rotator cuff tear in addition to acromioplasty (50 shoulders). Because surgery distorts landmarks, an understanding of the surgical procedures and their characteristic sonographic appearances is essential. After acromioplasty, the characteristic sharp margination or the acromion was replaced by a less distinct, irregular surface. After repair of a cuff tear, characteristic sonographic appearances included visualization of a reimplantation trough and loss of the echogenic subdeltoid bursa. When the cuff was intact after surgery, echogenicity was abnormal in all cases (17 shoulders). Sonography accurately diagnosed recurrent cuff tears in all 26 shoulders in which surgical proof was available and confirmed an intact cuff in 10 of 11 cases. In one shoulder, a cuff hematoma was incorrectly interpreted as a full-thickness tear. These findings suggest that sonography is an effective procedure for evaluating a postoperative patient with recurrent shoulder symptoms.
Since 1982 a sonographic technique has been devised to evaluate the integrity of the rotator cuff. In a series of 139 shoulders in 134 consecutive patients without prior surgery, sonographic results were correlated with surgical findings and/or arthrography. When sonography was compared with surgical findings (n = 90 shoulders), the overall accuracy was 95%. The sonographic diagnosis was the same as the arthrographic diagnosis in 91% of the cases (n = 50). Cuff lesions were also created in two cadavers, and images were made to confirm sonographic appearances. Because in the authors' experience sonography is accurate, safe, painless, rapid, and inexpensive, it has now been adopted as the primary study for the examination of the rotator cuff at the authors' institution. Arthrography is recommended in cases in which sonography is negative but there is significant clinical evidence of rotator cuff tear.
Twenty-nine soft tissue masses were studied with magnetic resonance imaging (MRI) which proved to be useful in the preoperative evaluation of these lesions. Other imaging modalities employed had significant limitations. Plain films were of little value because of the intrinsically low contrast of soft tissues. Angiography was not necessary unless MRI suggested a vascular lesion or proximity to major blood vessels. Computed tomography (CT) and MRI both readily identified fatty lesions and their relationship to adjacent structures. Some soft tissue tumors could not be delineated from normal muscle with CT, but were easily seen with MRI. MRI is ideally suited for the study of suspected soft tissue tumors because of its excellent soft tissue contrast and its ability to image directly in any plane. Optimum evaluation required imaging in at least two planes with spin echo sequences chosen to bring out both T1 and T2 features.
Since bone mass has been shown to be an important determining factor of fractures in vitro, we undertook a study to evaluate whether bone mass measurements could separate postmenopausal women with vertebral compression fractures from women of a similar age without fractures. We also wanted to see if methods of measuring bone mass at the spine would be more sensitive or specific than methods that measured bone at the wrist or the entire skeleton. The techniques used were: total body calcium by neutron activation analysis (TBC), single photon absorptiometry (SPA), dual photon absorptiometry (DPA), and quantitative computed tomography (QCT). Normal women aged 20-85 were measured, but only those greater than 50 yr were used in the analysis. Mean values for women with fractures were significantly lower than normals (p less than .001): TBC 642 +/- 103 g vs. 764 +/- 114; SPA .658 +/- .134 g/cm vs. .779 +/- .142; DPA 3.75 +/- .82 g/cm vs. 4.37 +/- .86; QCT 59.0 +/- 25.7 mg/cc vs. 92.6 +/- 36.0. However, each of the methods showed considerable overlap between women with and without fractures. At 90% specificity the sensitivities of the tests were: TBC 34%; SPA 29%; DPA 33%; QCT 36%. When values were expressed as the % expected (based on age and height) then the sensitivities were: TBC 52%; SPA 36%; DPA 35%; QCT 44%. Using Bayes' theorem, we constructed curves showing the posttest probability of these tests at a prevalence of 20%. None of these bone mass measuring techniques showed complete separation between normal and osteoporotic women with fractures; about one-half of the women with fractures were below the normal range. The risk of having a fracture increases as bone mass declines, but our data suggest that bone mass is not the only factor leading to vertebral fractures in postmenopausal women.
Orthopedic surgeons employ a wide variety of modern fixation devices in the treatment of fractures. In order to assess these instruments correctly, the radiologist should be aware of both their purpose and their normal appearance. A review of the common internal and external fixation devices used at a major trauma center and the complications of their use has been presented.
The authors reviewed the computed tomography (CT) scans, plain radiographs, and subsequent treatment of 17 patients with complex proximal humeral fractures. CT scans and radiographs were compared in the demonstration of fracture lines, displacement of fracture fragments, rotation of fragments relative to their normal positions, and status of the head and articular surface of the humerus. The impact of CT findings on the decision to treat with surgery versus closed reduction and on the choice of surgical procedure was assessed. Surgery was not performed in nine patients because CT scans showed no significant displacement of fragments previously judged displaced or "indeterminate" on radiographs. Surgery was performed in eight patients; CT demonstrated significant abnormalities not definitely shown with radiography. In six of these eight patients, CT scans demonstrated unsuspected abnormalities that directed the choice of surgical procedure. CT scans provide clinically useful information for the treatment of complex proximal humeral fractures when radiographs provide inadequate or indefinite information.
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We present a case of Ruvalcaba-Myhre-Smith syndrome, which, to our knowledge, has not been reported in the radiologic literature. This rare entity is characterized by intestinal polyps, macrocephaly, and hyperpigmented genital macules. The differentiation of this syndrome from other polyposis syndromes is discussed.
Bone mass was measured in 49 postmenopausal women by the following techniques: single photon absorptiometry at the radius (SPA), dual photon absorptiometry at the lumbar spine (DPA), quantitative computed tomography at the lumbar spine with an area of interest of only trabecular bone (QCT) or of an integrated cross-section of the vertebral body (QCTi), and total body calcium by neutron activation analysis (TBCa). Each women had two measurements with a one-year interval. Half of them were treated with calcium supplementation only; the other half also received calcitriol (1,25 dihydroxycholecalciferol). The aim of this report was to compare the changes of bone mass as measured by the different techniques. The DPA and QCTi values were significantly lower at one year than at baseline (by paired t-tests). The mean percent changes (+/- SD) for the measurements were: TBC, -0.4 +/- 4.6%; SPA-1, 1.2 +/- 7.1%; SPA-2, 0.7 +/- 6.0%; DPA, -2.5 +/- 11%; QCT, 6.5 +/- 23%; and QCTi, -6.0 +/- 9%. The percent changes by one technique did not show significant correlation to the percent changes by the other methods. We conclude that the precision of the methods in this clinical setting is not sufficient to show correlations after only one year; in addition, there may have been different rates of changes at different sites of the skeleton.
Skeletal abnormalities have been reported on numerous occasions in patients who have received high doses of vitamin A and its derivatives. Recently, a new derivative, isotretinoin (Accutane, Hoffman-LaRoche, Inc.), has become available for the treatment of cystic acne. Ninety-six patients treated for a minimum of four months with low doses of this drug at two University centers have shown overall good to excellent clinical responses. However, ten of these patients have developed small pointed excrescences on the anterior margins of cervical, thoracic, or lumbar vertebral bodies. The findings are of unknown clinical significance but show some similarities to the spinal findings in DISH syndrome. Follow-up studies will be obtained, but, at the present time, the drug still can be recommended for patients who have severe cystic acne because of the excellent clinical response.
Eighty-eight patients with 188 sacral fractures were examined with computed tomography (CT) and conventional radiography. Four main patterns of sacral injury were defined: sacroiliac diastasis (39%), sacral and/or iliac lip fractures (25%), vertical shear fractures (25%), and comminuted fractures (5%). Initial interpretation of plain radiographs failed to define 29% of the sacroiliac joint diastases, 57% of the lip fractures, 34% of the vertical shear fractures, and 25% of the comminuted fractures. The extent of injury was better delineated with CT, and a more certain diagnosis of sacral injury was possible with CT than with radiography. Because of the higher detection rate and improved imaging of fracture configuration, CT should be performed in all patients with sacral injury.
MRI has been shown to be very useful in the work-up of musculoskeletal neoplasms. The lack of ionizing radiation, the superb contrast resolution, and the ability to directly scan the sagittal and coronal planes make MRI a very attractive imaging mode for treatment planning. With spin-echo MRI, maximum contrast between tumor and fatty tissues generally occurs with short TR and TE times (T1-weighted images). Likewise, maximum contrast between tumor and muscle, tendon, or ligaments occurs with long values of TR and TE (T2-weighted images). Early experience suggests that the already exceptional contrast resolution seen with MRI can be improved even more with the administration of intravenous contrast agents. Just as with CT, fatty tumors can usually be easily distinguished from other tissue types with MRI by means of their differential intensity behavior at different pulse sequences. Fluid-filled tumors, such as unicameral bone cysts or aneurysmal bone cysts may be suspected in the same manner, especially if a fluid-fluid level is seen within the lesion. Otherwise, MRI has not been useful so far in noninvasively determining the histologic type of tumors. Our experience and that of others suggests that MRI is equal or superior to CT in the work-up of musculoskeletal neoplasms. This is especially striking when it is remembered that one is comparing an immature MRI technology with a mature CT technology. Although CT presently has a central role in the staging of musculoskeletal tumors, MRI will shortly supplant it in many cases.
This prospective study compares immediate and delayed patient discomfort in 177 patients following shoulder arthrography using intraarticular combinations of metrizamide, meglumine/sodium diatrizoate, meglumine diatrizoate, lidocaine, epinephrine, and air. Patients receiving conventional ionic monomeric positive contrast media had a 60% (90/150) incidence of moderate or severe delayed exacerbation of their baseline symptoms; only 14% (3/21) of patients receiving metrizamide, a nonionic contrast medium, had similar levels of postprocedural discomfort. Morbidity was somewhat diminished with the use of double-contrast (45%, 34/75) rather than single-contrast (75%, 56/75) examinations, and with avoidance of sodium-containing contrast agents or epinephrine. Nonionic or monovalent polymeric contrast media, despite their present high cost, may be the agents of choice if single-contrast arthrography is performed in joints (such as the shoulder, hip, and temporomandibular) associated with a high incidence of post-procedural pain.