MR imaging of fat-containing tumours: the distinction between lipoma and liposarcoma.

INTRODUCTION: This study aimed to retrospectively review the magnetic resonance (MR) imaging features of the lipomatous tumour in order to differentiate between lipoma and liposarcoma. METHODS: The MR images of 38 patients (24 female and 14 male with a mean age 48 years) in a consecutive five-year period, who had histologically verified lipoma (n is 29) and liposarcoma (n is 9), were retrospectively reviewed. The images were assessed for the number, site, size and margin of the lesions, as well as the signal intensity (homogenous, bright signal on T1-weighted [T1W] image, bright signal suppressed on T1W with fat-suppression image, bright signal on T2-weighted with fat-suppression image), the internal architecture (thin/thick septum, cystic change), the effect on the surrounding tissue (oedema, neurovascular involvement) and the enhancement pattern. RESULTS: A partially ill-defined margin, neurovascular involvement, enhancing thick/nodular septum and a partially bright signal intensity on T1W images were statistically significant MR imaging features that favoured a diagnosis of liposarcoma (p-value is less than 0.0001). Male gender, an internal cystic change and surrounding soft tissue oedema increased the risk of liposarcoma approximately 2.8, 3.5 and 3.5 times, respectively, compared with the reference group (lipoma), but this was not a statistically significant finding. Thick/nodular septum was significantly associated with liposarcoma compared with lipoma (odds ratio 69.3, 95 percent confidence interval 5.2-3184.8, p-value is less than 0.0001). CONCLUSION: Statistically significant MR imaging features that favour a diagnosis of liposarcoma included a partially ill-defined margin, neurovascular involvement, enhancing thick/nodular septum, and a partially bright signal intensity on T1W images. The most statistically significant predictor of liposarcoma was thick/nodular septum.

Humeral head ossification center in congenital heart disease.

The objective of this study was to evaluate the ossification (visualization) of proximal humeral ossification center (PHOC) which may indicate bone growth in infants with acyanotic and cyanotic congenital heart disease (HD) compared to normal infants. The medical records and chest radiographs within 3 months after birth of infants who were diagnosed as congenital HD by echocardiography or cardiac catheterization from 1989 to 1999 were reviewed. The PHOC was recorded from chest radiograph as presence or absence in every one-month interval since birth. In all cases, the corrected age of 0 month was defined as 40 weeks post conception. We used a study of 260 normal Korean infants as the normal population in this study. We found that from 67 cases enrolled in this study; 10 cases were excluded because of lack of complete medical records and sequential chest radiographs. In the remaining 57 cases, the average gestational age of the infants was 38.1 +/- 2.7 weeks and the average birth weight was 2860.5 +/- 597.7 grams. Female to male ratio was 1.28:1. The infants were classified by gestational age as term (75.4%) and pre-term (24.6%). Types of congenital HD were diagnosed from echocardiogram (96.5%) and cardiac catheterization (3.5%) of cases; and were divided as acyanotic HD (64.9%) and cyanotic HD (35.1%). The ossification of PHOC in acyanotic full-term infants at 0, 1, 2, and 3 months was 24.0 per cent, 32.0 per cent, 72.0 per cent and 88.0 per cent; in cyanotic full-term infants it was 27.8 per cent, 33.3 per cent, 77.8 per cent, and 94.4 per cent; and in acyanotic pre-term infants was 8.3 per cent, 8.3 per cent, 25.0 per cent, and 41.7 per cent, respectively. There were 2 cyanotic pre-term infants who did not show ossification of PHOC until 3 months. In full-term infants with both types of HD; the appearance of PHOC was significantly later than normal at 1 month corrected age (p = 0.000002) but not significant at 0, 2, and 3 months (p > 0.05); whereas, in pre-term infants with acyanotic HD, the appearance was later than normal at 1, 2, and 3 months (p = 0.02, p = 0.01, and p = 0.0002, respectively). We concluded that the ossification of PHOC is significantly later than normal in pre-term infants with congenital HD, but not significant in full-term infants with congenital HD.

False-negative meniscal tear in MR imaging using non fat-suppressed techniques.

Magnetic resonance (MR) imaging of menisci has a diagnostic accuracy of more than 90 per cent when the images are properly obtained. Errors in the interpretation of MR images may be related to many problems, resulting in false positive or false negative readings. We conducted this study to evaluate the prevalence of false negative results, using arthroscopy as gold standard. Matched MR imaging (performed before July 1997) and arthroscopic findings of the menisci in 63 consecutive patients were retrospectively reviewed separately by imaging planes and sequences used, by the site of tear, and by the site of meniscus (medial or lateral meniscus). The number and percentage of false-negative results were recorded. We found that with non fat-suppressed MR techniques, missed tear (false negative reading) of both menisci occurred predominantly in the meniscal body. The prevalence depends on imaging plane and sequence used. Among the techniques reviewed, sagittal T2-weighted (T2W) sequence had the highest prevalence of undetected meniscal tear.

Degenerative disk disease at lumbosacral junction: plain film findings and related MRI abnormalities.

Due to a wide range of normal disk space heights at lumbosacral (LS) junction, we conducted this study to evaluate how to diagnose degenerative disk disease (DDD) of LS junction and how much information we can obtain from plain radiography regarding this condition. We retrospectively reviewed lateral LS spine films and magnetic resonance (MR) imaging in 100 patients presented with low back pain. Anterior disk height (ADH) and posterior disk height (PDH) were directly measured from plain radiographs. Signs of DDD were recorded from both plain radiographs and MR imaging. We found that ADH < 11.3 mm or PDH < 5.5 mm indicate DDD at LS junction with 95 per cent confidence interval. When spondylolisthesis presented, disks were all degenerated. Endplate sclerosis had significant relative risk (p < 0.05) for lateral neural canal stenosis and disk herniation. No radiographic finding showed significant relative risk for nerve root compression.

An integrated approach to the evaluation of osseous tumors.

Modern treatment techniques for musculoskeletal neoplasms require significant imaging information to determine the nature and extent of tumors. The imaging investigation should be selected according to the information needed. Conventional radiographic techniques remain of fundamental importance in the analysis of bone tumors and tumor-like lesions, whereas advance imaging techniques such as CT and MR imaging can provide information regarding the extent of lesions.

Tuberculous tenosynovitis and bursitis: imaging findings in 21 cases.

PURPOSE: To describe imaging features of tuberculous tenosynovitis and bursitis with various imaging methods. MATERIALS AND METHODS: Twenty-one patients with surgically and/or pathologically proved tuberculosis of the tendon sheaths or bursae were evaluated. Routine radiography, arthrography, computed tomography (CT), and magnetic resonance (MR) imaging were used in some or all of the patients. RESULTS: Twelve patients had tuberculous tenosynovitis, and nine had bursitis. Tuberculous tenosynovitis most commonly involved the tendon sheaths of the hand and wrist, whereas bursitis occurred most frequently about the hip, especially in the trochanteric bursa. All cases of tuberculous tenosynovitis or bursitis showed soft-tissue swelling on plain radiographs, with calcification demonstrated in three of nine (33%) cases. CT and MR imaging allowed evaluation of all forms of tuberculous tenosynovitis (hygromatous, serofibrinous, and fungoid forms), whereas tuberculous bursitis exhibited two patterns of involvement: either a distended bursa or multiple small abscesses. Contrast material-enhanced radiography (i.e., arthrography) helped delineate communication between the affected structures. CONCLUSION: All imaging methods can provide complementary information that is helpful for determination of therapy. MR imaging seems to be superior in evaluating the extent of the lesion, particularly in soft tissue.

Tuberculous infection of the hand and wrist.

The authors report on 23 patients treated for tuberculosis of the hand and wrist during the past 20 years. Duration of symptoms prior to diagnosis ranged from several months to years. Swelling and pain on motion were common symptoms, as was increased sedimentation rate. Granulomatous inflammation was seen on paraffin section in most of the patients, however tissue cultures were positive for Mycobacterium tuberculosis in only 6 patients in this study. Treatment of these patients were divided into medical and surgical treatments. The incisional biopsy and antituberculous drug were carried out and administered in the medical-treated group for 2 years. The surgical synovectomy as well as debridement and administration of antituberculous drugs were carried out on the surgical group. The results showed no recurrence in this study. Most of the patients showed improved symptoms and an increased range of motion. In conclusion, this treatment resulted in good recovery of function with low morbidity.

A multicenter study on hip fractures in Thailand.

The present study is a multicenter study on hip fractures aimed at estimating the incidence among Thais. It also describes treatment modalities, associated medical care costs, complications, outcome of orthopedic care, length of stay in hospitals and duration of delay in seeking orthopedic care after occurrence of fractures. An extremely low hip fracture incidence of 7.05 per 100,000 population was found. Hip fracture was shown to increase steeply with age. An average of 26.44 days of delay in seeking orthopedic care following occurrence of hip fractures was reported. In contrast to the belief in Western countries that almost all hip fractures will seek orthopedic care, 7.8 per cent of these Thai cases denied orthopedic care during admission to hospitals. Median of charge to patients was 11205.00 baht, over one fourth of the national income per capita (36,563).

The heel-pad compressibility.

Heel-pad thickness and compressibility were studied in the feet of 400 normal subjects by loaded and unloaded lateral radiographs. The normal unloaded heel-pad thickness was 18.70 +/- 2.46 mm. The thickness was greater in men than in women and increased with age. The heel-pad compressibility index was 0.53 +/- 0.09. The compressibility increased with age, but there was no significant difference with gender. An increase in body weight led to an increase in heel-pad thickness and loss of elasticity.