Biomedical subjects

A J Peduto

Publications and source records attributed to A J Peduto.

9 recordsLinked to original sources

PubMed2006

Achilles tendon imaging.

The Achilles tendon is the largest and strongest tendon in the body, yet one of the most commonly injured. Tendon degeneration is a relatively common disorder, predisposing to tears and often associated with paratenonitis. Numerous other diseases involve the Achilles tendon, some with classic imaging appearances, others with non-specific appearances. The aim of this pictorial essay is to review the radiographic, computed tomographic, ultrasonographic and MR appearances of the normal and diseased Achilles tendon.

Achilles Tendon↗

PubMed2002

Risk factors for fractures of the wrist, shoulder and ankle: the Blue Mountains Eye Study.

Few studies have examined risk factors for fractures of the wrist, shoulder or ankle. The Blue Mountains Eye Study is a population-based longitudinal study in 3654 people aged 49 years or older resident in an area west of Sydney, Australia. Detailed eye examinations and interviews were carried out at baseline (1992-3) and after 5 years (1997-9). Information about fractures sustained during follow-up were collected by a combination of self-report and a search of hospital radiology records. After 4.7 years follow-up subjects had sustained 53 fractures of the distal forearm, 20 fractures of the proximal humerus and 33 ankle fractures. In multivariate models factors independently associated with wrist fractures in women were no vigorous exercise in the past 2 weeks (relative risk RR 0.4, 95% CI 0.2-0.9) and ever use of HRT (RR 0.4, 95% CI 0.1-1.0). Factors independently associated with ankle fractures were male sex (RR 0.3, 95% CI 0.1-0.8) and visual field loss (RR 2.8, 95% CI 1.2-6.6). These findings are in keeping with other studies, and suggest that different types of osteoporotic fracture have different, if overlapping, sets of risk factors.

Aged↗

PubMed2001

Diabetes and risk of fracture: The Blue Mountains Eye Study.

OBJECTIVE: To examine associations between measures of diabetes and risk of fracture in a population-based sample of older Australians. RESEARCH DESIGN AND METHODS: This was a prospective study of 3,654 subjects aged 49 years and older who were residents in the Blue Mountains, west of Sydney, Australia. At baseline, subjects were asked questions about history and treatment of diabetes, and fasting blood samples were taken. Photographs were taken of the retina and lens to grade retinopathy and cataract. Details of fractures (excluding rib and vertebral fractures) were collected by a combination of self-report and medical record searches; all fractures were radiologically confirmed. RESULTS: After 2 years of follow-up, we found that several diabetes-related factors were significantly associated (in multivariate models) with increased risk of all fractures combined, including presence of diabetic retinopathy (adjusted RR 5.4, 95% CI 2.7-10.8), diabetes duration > or = 10 years (3.3, 1.3-8.2), cortical cataract involving > or = 25% of the lens area (2.5, 1.3-4.7), and insulin treatment (5.9, 2.6-13.5). The proximal humerus was the only individual fracture site associated with diabetes. Diabetic retinopathy (10.3, 2.2-48.0), diabetes duration (for > or = 10 years duration; 11.4, 2.4-54.2), and insulin treatment (18.8, 4.0-88.7) were all associated with proximal humerus fracture. CONCLUSIONS: These data suggest a significantly increased risk of fracture associated with diabetic retinopathy, advanced cortical cataract, longer diabetes duration, and insulin treatment. However, there are some shortcomings in this study that may limit these findings.

Aged↗

PubMed2000

Magnetic resonance imaging and diseases of the liver and biliary tract. Part 2. Magnetic resonance cholangiography and angiography and conclusions.

Magnetic resonance cholangiography (MRC) relies on the strong T2 signal from stationary liquids, in this case bile, to generate images. No contrast agents are required, and the failure rate and risk of serious complications is lower than with endoscopic retrograde cholangiopancreatography (ERCP). Data from MRC can be summated to produce an image much like the cholangiogram obtained by using ERCP. In addition, MRC and conventional MRI can provide information about the biliary and other anatomy above and below a biliary obstruction. This provides information for therapeutic intervention that is probably most useful for hilar and intrahepatic biliary obstruction. Magnetic resonance cholangiography appears to be similar to ERCP with respect to sensitivity and specificity in detecting lesions causing biliary obstruction, and in the diagnosis of choledocholithiasis. It is also suited to the assessment of biliary anatomy (including the assessment of surgical bile-duct injuries) and intrahepatic biliary pathology. However, ERCP can be therapeutic as well as diagnostic, and MRC should be limited to situations where intervention is unlikely, where intrahepatic or hilar pathology is suspected, to delineate the biliary anatomy prior to other interventions, or after failed or inadequate ERCP. Magnetic resonance angiography (MRA) relies on the properties of flowing liquids to generate images. It is particularly suited to assessment of the hepatic vasculature and appears as good as conventional angiography. It has been shown to be useful in delineating vascular anatomy prior to liver transplantation or insertion of a transjugular intrahepatic portasystemic shunt. Magnetic resonance angiography may also be useful in predicting subsequent variceal haemorrhage in patients with oesophageal varices.

Biliary Tract Diseases↗

PubMed2000

Magnetic resonance imaging (MRI) and diseases of the liver and biliary tract. Part 1. Basic principles, MRI in the assessment of diffuse and focal hepatic disease.

Magnetic resonance imaging (MRI) relies on the physical properties of unpaired protons in tissues to generate images. Unpaired protons behave like tiny bar magnets and will align themselves in a magnetic field. Radiofrequency pulses will excite these aligned protons to higher energy states. As they return to their original state, they will release this energy as radio waves. The frequency of the radio waves depends on the local magnetic field and by varying this over a subject, it is possible to build the images we are familiar with. In general, MRI has not been sufficiently sensitive or specific in the assessment of diffuse liver disease for clinical use. However, because of the specific characteristics of fat and iron, it may be useful in the assessment of hepatic steatosis and iron overload. Magnetic resonance imaging is useful in the assessment of focal liver disease, particularly in conjunction with contrast agents. Haemangiomas have a characteristic bright appearance on T2 weighted images because of the slow flowing blood in dilated sinusoids. Focal nodular hyperplasia (FNH) has a homogenous appearance, and enhances early in the arterial phase after gadolinium injection, while the central scar typically enhances late. Hepatic adenomas have a more heterogenous appearance and also enhance in the arterial phase, but less briskly than FNH. Hepatocellular carcinoma is similar to an adenoma, but typically occurs in a cirrhotic liver and has earlier washout of contrast. The appearance of metastases depends on the underlying primary malignancy. Overall, MRI appears more sensitive and specific than computed tomography with contrast for the detection and evaluation of malignant lesions.

Biliary Tract Diseases↗

PubMed1999

MR imaging of dysplasia epiphysealis hemimelica: bony and soft-tissue abnormalities.

OBJECTIVE: The purpose of this study is to describe the bony and, to our knowledge, previously unreported associated soft-tissue abnormalities seen on MR imaging of dysplasia epiphysealis hemimelica. CONCLUSION: MR imaging accurately depicted bony and cartilagenous structural abnormalities in multiple planes and revealed previously undescribed secondary changes in menisci, tendons, ligaments, and muscle. MR imaging is of value in the assessment of patients with this disorder.

Bone Diseases, Developmental↗

PubMed1997

Using MR imaging to diagnose partial tears of the anterior cruciate ligament: value of axial images.

OBJECTIVE: The purpose of this study was to determine the usefulness of axial MR imaging for diagnosing partial anterior cruciate ligament (ACL) tears and to determine if patients could be categorized as having stable or unstable partial ACL tears on the basis of criteria of axial MR imaging. MATERIALS AND METHODS: We reviewed 238 patients who, over a 2-year period, underwent both MR imaging of the knee and arthroscopic evaluation of the ACL. According to arthroscopic examination, these patients had 143 normal ACLs, 67 complete ACL tears, and 28 partial tears. The 28 partial tears included 20 stable tears (no ACL deficiency) and eight unstable partial tears having ACL deficiency or requiring ACL reconstructive surgery. The axial MR images were retrospectively reviewed by two interpreters who were unaware of the arthroscopic findings, and decisions were reached by consensus. The ACL was classified according to its axial configuration and continuity. RESULTS: By axial MR imaging criteria, we found 109 elliptical ACLs, 45 attenuated ACLs, three ACLs with increased intrasubstance signal intensity, six isolated ACL bundle signs, 19 ACLs that could not be visualized, and 56 cloudlike mass signs. Arthroscopically normal ACLs and stable partial tears were difficult to distinguish reliably on axial MR images. Unstable partial ACL tears could not be distinguished from complete ACL tears. However, using axial MR imaging, our observers were able to segregate stable ACLs (normal ligaments and stable partial tears) from unstable ACLs (unstable partial tears and complete tears) with 100% sensitivity and 96% specificity. CONCLUSION: Axial MR imaging of the ACL may provide important diagnostic information for patients who have ACL injury. On axial MR images, stable ACLs were elliptical, attenuated, or showed as areas of increased intrasubstance signal intensity. At arthroscopy, attenuated ACLs represented normal ACLs (76%) and stable partial tears (24%). On axial MR images, the configurations that indicated unstable ligaments were isolated ACL bundle, nonvisualized ACL, and cloudlike mass.

Adult↗

PubMed1996

MR imaging of the adult elbow.

Magnetic resonance (MR) imaging can provide important diagnostic information in the evaluation of the adult elbow. Optimal imaging technique should include the use of proper positioning, surface coils, and appropriate sequences and imaging planes as indicated by the suspected abnormalities. A familiarity with the anatomy of the normal elbow is crucial to identifying pathologic entities correctly and avoiding diagnostic pitfalls. Disruption of the collateral ligaments can best be demonstrated with thin-section coronal gradient-echo MR images. Injuries to the flexor and extensor muscle groups, biceps muscles, and triceps muscles require T2-weighted or short-inversion-time inversion recovery (STIR) MR images in the long and short axes of the affected muscle. The evaluation of osteochondral lesions and intraarticular bodies is optimized with T1-weighted and STIR MR images. Synovial processes usually necessitate the intravenous administration of gadopentetate dimeglumine to distinguish joint fluid from pannus. The contents of the cubital tunnel are best visualized on axial T1-weighted and STIR MR images. Masses arising in or near the elbow should be imaged with multiple sequences in at least two planes, and involvement of adjacent vital structures should be carefully evaluated.

Adult↗

PubMed1996

MR imaging of the rotator cuff mechanism: comparison of spin-echo and turbo spin-echo sequences.

OBJECTIVE: Although well documented in other MR imaging applications, the value of turbo spin-echo sequences in evaluating the shoulder has not been addressed. This study was designed to directly compare matched spin-echo and turbo spin-echo sequences in the MR imaging evaluation of the rotator cuff. MATERIALS AND METHODS: Using otherwise matched double-echo sequences of equal time duration, we performed 123 paired spin-echo (TR/TE, 200/25,75; one excitation) and turbo spin-echo (3500-5000/22,90; two excitations) sequences in the paracoronal and/or parasagittal plane of the shoulders of 76 patients referred to our institution for possible rotator cuff tear. The sequences were retrospectively analyzed for cuff signal and morphology, fluid conspicuity, coracoacromial arch morphology, and bone marrow signal abnormalities. Surgical and nonsurgical clinical results were correlated when available. RESULTS: We found 100% diagnostic correlation between spin-echo and turbo spin-echo sequences for rotator cuff integrity. Surgical data were available for 26 patients, and clinical follow-up for another 37. For complete rotator cuff tear in the surgical subpopulation, sensitivity was 89%, specificity was 94%, and diagnostic accuracy was 24 of 26 (92%). We found no diagnostically significant difference between the two imaging sequences for fluid conspicuity, coracoacromial morphology, or marrow signal. Signal-to-noise ratios were superior in the turbo spin-echo sequences. CONCLUSION: Turbo spin-echo sequences are an accurate and efficient tool in the MR imaging evaluation of the rotator cuff. Potential benefits include time saving, increased spatial resolution, and improved signal-to-noise ratio.

Adolescent↗