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Biomedical subjects

T C Demos

Publications and source records attributed to T C Demos.

At least 19 recordsLinked to original sources

Radiologic case study. Fractures of the foot masquerading as ankle injuries.

An ankle radiographic series frequently is obtained when a patient presents with an acute ankle and foot injury. Although many fractures are confined to the ankle and are readily apparent, fractures of the foot can mimic ankle injuries. It is important to differentiate these fractures of the foot from the more common ankle sprain. Most ankle sprains are treated with ice, compression, and elevation, followed by range-of-motion exercises and progressive weight bearing as tolerated. When foot fractures are not identified, however, lack of appropriate treatment can result in late complications. Concentration on key areas as described here will reduce the incidence of missed fractures of the foot in these patients.

Adult

Enlarged peroneal process with peroneus longus tendon entrapment.

A 50-year-old man was treated conservatively for chronic bilateral ankle pain for several years. Plain radiographs obtained following exacerbation of symptoms showed bilateral enlarged peroneal processes. CT and MRI demonstrated bony detail of the unusual processes and also showed isolation of the peroneus longus tendons and associated tendinitis and partial tears.

Ankle

Evaluation of image quality using 1 : 1 pitch and 1.5 : 1 pitch helical CT in children: a comparative study.

OBJECTIVE: The objective of this study was to compare the quality of 1 : 1 and 1.5 : 1 pitch helical contrast-enhanced thoracic and abdominal CT images in children who cannot cooperate for breath holding. MATERIALS AND METHODS: This is a retrospective study of 33 contrast-enhanced CT examinations in 11 children of 0-4 years of age. All children had an initial CT study using 1 : 1 pitch helical scanning followed over the next 6-36 months by one to four CT examinations with 1.5 : 1 pitch. Radiation dose with the two techniques was measured with a pencil ionization chamber. RESULTS: The two techniques provided comparable overall image quality. There was 33 % less radiation dose with 1.5 : 1 pitch helical scanning. CONCLUSION: The 1.5 : 1 pitch helical CT provides comparable quality images and a smaller radiation dose than 1 : 1 pitch in examining children aged 0-4 years.

Child

Multifocal vascular lesions of bone: imaging characteristics.

OBJECTIVE: Multifocal vascular processes which arise in bone are a very inhomogeneous class of diseases. Four of these processes are derived from endothelial precursors, however, and share a similar radiographic spectrum. These four entities are reviewed in order to clarify their imaging patterns and the diagnostic utility of imaging modalities. METHODS: Eight cases of cystic angiomatosis, multifocal hemangioma, hemangioendothelioma and angiosarcoma presenting to a tertiary referral center over a 7-year period were reviewed. The medical literature was also reviewed for information concerning the imaging of these processes. RESULTS: All four diseases produced radiolucent defects on plain radiographs with variable margination reflecting the aggressiveness of the lesions. Computed tomography was used to examine five patients and provided supportive, though generally non-diagnostic, information in the five cases in which it was performed. Radionuclide bone scintigraphy, as reported in the literature, underestimated the extent of skeletal involvement in all eight cases, though some lesions were identified. Radionuclide imaging with labeled red blood cells, performed in three cases, did not add any information, which is contrary to some reports in the literature. Magnetic resonance imaging proved the most sensitive for identifying lesions, although the imaging characteristics were not diagnostic. CONCLUSIONS: Plain radiographs are the mainstay for imaging multifocal endothelial processes. Radiographs provide information on aggressiveness, multifocality and distribution of lesions. Computed tomography provides similar information. Magnetic resonance imaging often detects additional lesions. The insensitivity of radionuclide bone scintigraphy is surprising. Reports of unique deposition of radionuclide in tagged red blood cell scanning has been reported to support the diagnosis of vascular lesions, but it did not do so in these cases.

Adolescent

Congenital and acquired lung hernias.

Lung hernia is defined as a protrusion of lung parenchyma beyond the confines of the musculoskeletal thorax. Lung hernias can be classified according to location (i.e., cervical, thoracic, or diaphragmatic) and etiology. Approximately 80% of reported cases of lung hernia are acquired, usually related to trauma or surgery. Symptoms are few, infrequent, and vague. A painless, local, and inconstant bulging is evident on physical examination. The diagnosis of a lung herniation is accomplished using chest radiographs in the most cases. Surgery is usually reserved for large hernias or incarcerated hernias.

Hernia

Longitudinal tibial stress fracture.

Fatigue-type stress fractures occur following repetitive loading of normal bone. These occur frequently in the tibia, although vertical orientation to the fracture is much less common than transverse orientation. Without a convincing history of new or accelerated muscular activity, imaging can be difficult to interpret and evaluation may require more than one imaging modality to exclude other diagnostic considerations, including neoplasm and osteomyelitis.

Adolescent

Helical computed tomography at 1.5:1 pitch reconstructed at 15-mm and 7-mm intervals for examination of patients with suspected metastatic disease.

OBJECTIVE: To document the need for overlapped reconstruction when using helical computed tomography (CT) software that reconstructs 10-mm-collimation, 1.5:1-pitch images at 15-mm intervals in follow-up examination of patients with suspected metastatic disease. PATIENTS AND METHODS: Forty consecutive patients with known or suspected metastatic disease were examined with helical CT at 10-mm collimation and 1.5:1 pitch. The studies were examinations of the chest, abdomen and pelvis; the chest and abdomen; or the abdomen and pelvis. Two image sets, one prospectively reconstructed at 15-mm intervals and the other retrospectively reconstructed at 7-mm intervals, were independently reviewed by three radiologists, and the number, size and location of lesions were documented. Differences in interpretation were resolved by consensus. The lesions detected on the two sets of images were classified according to lesion size and location, and the results were analysed by multivariate analysis of variance with repeated measures. RESULTS: Images reconstructed at 7-mm intervals revealed a total of 436 lesions, 127 (41%) more than were revealed by images reconstructed at 15-mm intervals. The number of lesions less than 1 cm in diameter that were visible in the two sets of images was significantly different (p = 0.018). However, there was no significant difference between the two sets of images in terms of lesion location. CONCLUSION: Metastatic lesions may be missed by helical CT at 1.5:1 pitch if overlapped reconstruction is not performed.

Abdominal Neoplasms

Hereditary deficiency of protein C, protein S and antithrombin III.

It is estimated that 5% of patients with deep vein thrombosis and 50% of those with recurrent thrombosis have an inherited abnormality of coagulation, most commonly deficiency of protein C, protein S or antithrombin III. These disorders should be suspected when venous thrombosis occurs in a young person, if there is a family history of thrombosis, if thrombosis occurs at an unusual site or if there is recurrent thrombosis with no predisposing factors. Affected patients are treated with lifelong anticoagulation therapy. Thromboembolism and its sequelae often produce abnormal findings on radiologic examinations, and therefore the radiologist who is familiar with these abnormalities is in a position to be the first to suggest the diagnosis.

Adult

Herniation of the transverse colon: an unusual complication of pedicled omentoplasty.

Pedicled omentoplasty is frequently used in chest reconstruction and treatment of sternal infection. The procedure is effective, but it is associated with several postoperative complications. The authors describe a 49-year-old man in whom sternal infection after heart surgery was successfully treated by sternectomy and omentoplasty. Several months later, the transverse colon herniated into the transposed omentum. To the authors' knowledge, this complication has not been previously reported.

Colonic Diseases