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Biomedical subjects

M L Richardson

Publications and source records attributed to M L Richardson.

At least 19 recordsLinked to original sources
PubMed1996

Prevalence of muscle injury following intra-arterial chemotherapy.

OBJECTIVE: Intra-arterial chemotherapy (IAC) is frequently used as an adjuvant treatment for musculoskeletal tumors. Past studies have noted that IAC not only induces favorable effects in tumor, but may also cause muscle edema and necrosis in previously normal tissue, reflected as increased signal on T2-weighted scans. In order to evaluate the prevalence of these effects, we reviewed all patients receiving IAC and MRI at our institution. METHODS: Our study population consisted of 24 patients who underwent IAC. All subjects were studied with MRI both pre- and post-IAC. None of the subjects in this study underwent surgery or radiation therapy until after the post-IAC MRI examination. Any muscle group involved by the tumor or peritumoral edema on the initial scan was excluded from the study. Catheter position during IAC was recorded as central or peripheral. Scans were scored positive if muscle groups in regions remote from the tumor site demonstrated increased T2 signal following IAC. RESULTS: Six out of these 24 patients (25%) were found to have positive results. A significant association was found between peripheral catheter position and a positive scan post-IAC (Fisher's exact test, P = 0.024). CONCLUSION: Because of our exclusion criteria, we are convinced that the finding of increased T2 signal in 25% of our patients was caused by IAC and represents muscle edema or necrosis. Knowledge of this post-chemotherapy MR finding should help prevent confusion during the interpretation of follow-up MR examinations.

Adult↗
PubMed1996

MR characterization of post-irradiation soft tissue edema.

OBJECTIVE: Radiation therapy is often used to treat bone und soft tissue neoplasms, and commonly results in soft tissue edema in the radiation field. However, the time course, distribution and degree of this edema have not been well characterized. Our study was carried out to better define these features of the edema seen following neutron and photon radiation therapy. DESIGN AND PATIENTS: Two hundred and twenty-six patients underwent radiation therapy as part of combined modality management for musculoskeletal sarcomas between 1985 and 1993. Of these, 15 had surgical resection of their neoplasm, had no clinical evidence of recurrent disease, and had adequate MR follow-up that allowed sequential assessment of soft tissue following irradiation. Ten patients received photons with an average dose of 52.8 Gy. Five patients received neutrons with an average dose of 17.3 nGy. Sequential MR follow-up was available in these patients for an average of 22.8 months following radiation therapy. On each of the serial MR imaging studies, subcutaneous fat, muscle, and the intramuscular septa/fascial planes were graded subjectively as to size and signal intensity. RESULTS: In general, soft tissue signal intensity in the radiation field initially increased over time, peaking at about 6 months for neutron-treated patients and at about 12-18 months for photon-treated patients. Signal intensity then decreased slowly over time. However, at the end of the follow-up period, signal intensity remained elevated for most patients in both groups. Signal intensity in a particular tissue was greater and tended to persist longer on STIR sequences than on T2-weighted sequences. Survival analysis of signal intensity demonstrated much longer edema survival times for neutron-treated patients than for photon-treated patients. Signal intensity increase in the intramuscular septa persisted for much longer than for fat or muscle. A mild increase in size was noted in the subcutaneous fat and intramuscular septa. Muscle, on the other hand, showed a decrease in size following treatment. This was mild for the photon-treated group and more marked for the neutron-treated group. CONCLUSIONS: There is a relatively wide variation in the duration and degree of post-irradiation edema in soft tissues. This edema seems to persist longer in the intramuscular septa than in fat or muscle. Although the duration of follow-up was limited, our study suggests that this edema resolves in roughly half the photon-treated patients within 2-3 years post-treatment and in less than 20% of neutron-treated patients by 3-4 years post-treatment. Muscle atrophy was seen in both photon- and neutron-treated patients, but was more severe in the neutron-treated group.

Adipose Tissue↗
PubMed1995

Needle aspiration lung biopsy: reevaluation of the blood patch technique in an equine model.

PURPOSE: To reexamine the blood patch technique in a laboratory model of lung biopsy free of confounding clinical variables. MATERIALS AND METHODS: An equine model of lung biopsy was developed with an excised lobe connected to an insufflation bulb and pressure monitor. Patched and control unpatched punctures were made in the lung surface, and the pressure within the lung was raised to the maximum achievable. Whether air leakage from the puncture sites could be induced was determined and, if so, at what pressure it occurred. RESULTS: At statistical analysis with the Kaplan-Meier test and the Cox proportional hazards regression model, the difference between failure of the patched and unpatched punctures was statistically significant (P < .0001). CONCLUSION: The blood patch technique is effective in the laboratory setting and deserves reevaluation in a clinical series with updated biopsy techniques.

Animals↗
PubMed1995

A World-Wide Web radiology teaching file server on the Internet.

OBJECTIVE: Radiology departments have traditionally used film-based collections of interesting cases for teaching purposes. Film-based files are expensive to create and duplicate, and they physically occupy considerable space. As one solution to these problems, our department created an on-line radiology teaching file in digital format. MATERIALS AND METHODS: Our teaching file resides on a Macintosh Quadra 700 computer that is connected to the Internet, a worldwide network of interconnected computers, via our campus Ethernet network. Our digital teaching file images and text are composed in HyperText Markup Language (HTML) and are made available to the world with Webserver software known as MacHTTP. These teaching files are accessed using World-Wide Web (WWW) client software such as Mosaic, MacWeb, or Netscape. RESULTS: Our digital teaching file is available at no charge to anyone in the world with access to the Internet and WWW client software. Our radiology residents can access this file via several workstations in our department. Mosaic is an easy-to-use interface, and the use of our digital teaching file has increased significantly. In the 3 months since its creation, our teaching file has been accessed not only by our radiology residents but also by hundreds of other users in 33 countries. CONCLUSION: Use of Mosaic and the WWW format has resulted in an easy-to-use hypertext interface to the Internet, which allows even persons with little computer experience to navigate through the Internet, read text files, view images (stills and movies), and download files by merely pointing with the mouse and clicking on items of interest. This has allowed us to maintain a central teaching file that is physically small and easy to share with all the hospitals in our system. We invite the worldwide radiology community to access these files and to submit cases from their own teaching files to share with the rest of the world.

Computer Communication Networks↗
PubMed1995

Quantitative magnetic resonance imaging predicts clinical outcome of core decompression for osteonecrosis of the femoral head.

OBJECTIVE: To determine whether the course of femoral head osteonecrosis after core decompression can be predicted from the extent of necrotic bone in the preoperative magnetic resonance imaging (MRI). METHODS: In 31 femoral head lesions (Ficat stage I or II), the percentage volume of necrotic bone was calculated by dividing the sum of the necrotic areas from all MRI slices by the sum of the femoral head areas. Osteonecrosis risk factors, pain scores, and the need for further surgery were assessed at a minimum of 12 mo post-core decompression. Clinical outcomes were considered good when post-core decompression pain scores improved and further surgery was not required. RESULTS: Fourteen of the 15 hips with good outcomes after a mean followup of 32 mo had less than 21% femoral head involvement. All 16 hips with poor outcomes after a mean followup of 17 mo had more than 21% of the femoral head affected. CONCLUSION: Quantitative MRI of femoral head necrosis was a useful predictor of clinical outcome following core decompression.

Adult↗
PubMed1994

MR appearance of skeletal neoplasms following cryotherapy.

Cryotherapy is an increasingly popular mode of therapy adjunctive to surgical curettage in the treatment of certain skeletal neoplasms, such as giant cell tumors or chondrosarcomas. The magnetic resonance (MR) findings following cryotherapy have not been previously reported. We reviewed the MR findings in seven patients with skeletal neoplasms following curettage and cryotherapy. In six cases we found a zone of varying thickness extending beyond the surgical margins, corresponding to an area of cryoinjury to medullary bone. This zone displayed low signal intensity on T1-weighted images and high signal intensity on T2-weighted images, consistent with the presence of marrow edema. This zone of edema almost certainly reflects underlying thermal osteonecrosis. This zone may vary in size and intensity over time as the area of cryoinjury evolves or resolves. MR is currently the imaging procedure of choice for follow-up of most musculoskeletal neoplasms. Knowledge of the MR findings following cryotherapy should help prevent confusion during the interpretation of follow-up MR examinations.

Adult↗
PubMed1994

Displaying radiologic images on personal computers: practical applications and uses.

This is the fifth and final article in our series for radiologists and imaging scientists on displaying, manipulating, and analyzing radiologic images on personal computers (PCs). There are many methods of transferring radiologic images into a PC, including transfer over a network, transfer from an imaging modality storage archive, using a frame grabber in the image display console, and digitizing a radiograph or 35-mm slide. Depending on the transfer method, the image file may be an extended gray-scale contrast, 16-bit raster file or an 8-bit PC graphics file. On the PC, the image can be viewed, analyzed, enhanced, and annotated. Some specific uses and applications include making 35-mm slides, printing images for publication, making posters and handouts, facsimile (fax) transmission to referring clinicians, converting radiologic images into medical illustrations, creating a digital teaching file, and using a network to disseminate teaching material. We are distributing a 16-bit image display and analysis program for Macintosh computers, Dr Razz, that illustrates many of the principles discussed in this review series. The program is available for no charge by anonymous file transfer protocol (ftp).

Audiovisual Aids↗
PubMed1994

Diagnostic performance of magnetic resonance imaging for the diagnosis of rotator cuff tears using supplemental images in the oblique sagittal plane.

RATIONALE AND OBJECTIVES: The authors evaluated the diagnostic utility of supplemental imaging in the oblique sagittal (OS) plane for the magnetic resonance imaging (MRI) diagnosis of rotator cuff tears. METHODS: Two radiologists with varying levels of MRI experience blindly reviewed shoulder MR examinations of 50 patients for rotator cuff tears. Shoulder examinations were interpreted twice, initially using only double-echo spin-echo images obtained in the oblique coronal (OC) plane and later using double-echo spin-echo images obtained in the both the OC and OS planes. Tears were characterized according to size, location, and extent, and levels of diagnostic confidence were evaluated. RESULTS: Sensitivity and specificity of MR for the diagnosis of rotator cuff tear was 85% and 80%, respectively, with the OC series increasing to 95% and 93%, respectively with OCOS scans. However, these increases were not statistically significant. Receiver operating characteristic (ROC) curves suggest a trend toward increased diagnostic confidence when supplemental OS scans are available, especially for the less experienced reader. Characterization of rotator cuff tears was not improved with additional OS images. CONCLUSIONS: Supplemental OS scans did not demonstrate a definite improvement in diagnostic accuracy for rotator cuff tears compared to OC scans alone. Estimations based on sample size calculations indicate that a much larger population of patients would be needed to show a statistically significant difference.

Humans↗
PubMed1994

Age-related changes in marrow distribution in the shoulder: MR imaging findings.

PURPOSE: To define age-specific patterns of distribution of red and yellow marrow about the shoulder. MATERIALS AND METHODS: Red and yellow marrow distribution was reviewed on magnetic resonance images of 189 subjects aged 15-69 years. Double-echo and fast spin-echo, gradient, and short inversion time inversion recovery pulse sequences were used. The acromion, glenoid, and proximal humeral epiphysis, metaphysis, and diaphysis in each shoulder were graded semiquantitatively and qualitatively. RESULTS: There was a wide variation in the normal pattern of red-yellow marrow distribution both among subjects and among locations. All five anatomic locations showed an orderly progression from greater to lesser amounts of red marrow with increasing age. Many of the subjects had focal subchondral red marrow in the epiphysis, which was associated with patient age (P = .0001) and gender (P = .04). CONCLUSION: Knowledge of normal patterns of marrow distribution can prevent their being misinterpreted as marrow-based disease.

Acromion↗
PubMed1994

Radiographic changes in acute exacerbations of cystic fibrosis in adults: a pilot study.

OBJECTIVE: We set out to determine whether specific findings can be seen on chest radiographs of adult patients with cystic fibrosis who are having acute exacerbation of respiratory disease. MATERIALS AND METHODS: Over a 2-year period, 22 adults with cystic fibrosis had both a baseline chest radiograph and a radiograph obtained either because of acute exacerbation or for some other reason (nonexacerbation). Fourteen radiographic features, including mucous plugs, air-space disease, peribronchial thickening, bronchiectasis, fluid levels, and lymphadenopathy, were scored retrospectively by two radiologists, who did not have knowledge of the patient's clinical condition, as being present, absent, increased, decreased, or unchanged. An overall assessment (better, worse, or no change) was also given for each radiograph. Data were analyzed in two ways (per individual episode and per individual patient) by using contingency tables, with statistical significance determined by exact permutation testing. RESULTS: Of the 22 patients, 13 had 29 exacerbations and eight had 11 nonexacerbations. The remaining patient had radiographs showing both an exacerbation and a nonexacerbation. With the exception of overall change (p = .06), none of the radiographic variables showed a statistically significant association with exacerbation (mean p value, .66; range, .19-.90). CONCLUSION: The 14 specific radiographic findings studied, including peribronchial thickening, mucous plugs, air-space disease, and fluid levels, were not useful in determining whether an adult patient with cystic fibrosis was having acute exacerbation of the disease. With regard to these individual variables, chest radiographs are not helpful in the management of acute exacerbation of cystic fibrosis in adults. However, overall change approached statistical significance (p = .06). The value of chest radiography lies more in excluding the rare major complication, such as pneumothorax, than in diagnosing the usual exacerbation.

Acute Disease↗
PubMed1993

An inexpensive computer-based digital imaging teaching file.

Despite a decade and a half of digital imaging in radiology, most radiology teaching files remain film-based. The reasons include the high cost or unavailability of digital acquisition and display devices. In the past few years, a number of excellent exhibits that combine inexpensive microcomputers with radiologic education have been shown at national meetings [1-6]. Unfortunately, many of these methods require esoteric hardware, expensive or proprietary software, or special programming skills. We developed a simple method for creating and disseminating a teaching file of imaging studies obtained with digital techniques.

Computer-Assisted Instruction↗
PubMed1993

How should radiologists reply when patients ask about their diagnoses? A survey of radiologists' and clinicians' preferences.

Radiologists must consider several factors when asked by a patient to disclose the results of a radiologic examination. This study represents a survey of radiologists' and clinicians' opinions regarding disclosure of information to patients by the radiologist. A clearer understanding of the preferences of radiologists and clinicians may serve to improve communication and enhance cooperation between the two groups, with the ultimate result being improved patient care.

Attitude of Health Personnel↗
PubMed1993

Using a personal computer to create anatomic drawings for publication.

A chronic need exists for anatomic drawings that are suitable for publication. The best drawings of this type are the result of close collaboration between a trained medical illustrator and the author commissioning the artwork. However, high-quality drawings usually command premium prices and are not within everyone's budget. Similarly, services that can provide such illustrations are not available in all areas. This paper describes several methods of producing high-quality anatomic drawings with a personal computer. These drawings can be produced from the digital images obtained on one's local CT or MR scanners, or from digitized slides and photographs. Other images can be scanned from various sources of anatomic line art that are in the public domain. A final source of anatomic drawings is commercially available medical clip art. The drawings created from any of these sources can be modified to suit one's needs and can provide very satisfactory results.

Medical Illustration↗
PubMed1993

Intradural recurrence with chondrosarcoma of the spine. A case report and review of the literature.

Known for its resistance to chemotherapy and radiation therapy, chondrosarcoma remains largely a surgically managed tumor predisposed to local recurrence and late distant metastasis. A 42-year-old man with known thoracic chondrosarcoma developed progressive low back pain, lower extremity weakness, and urinary incontinence. Magnetic resonance imaging and computed tomographic myelography demonstrated multiple filling defects throughout the lumbosacral region. Surgical excision of these lesions disclosed intradural, extramedullary drop metastases of the chondrosarcoma. The spread of neoplasms within the dural space is uncommon, accounting for less than 5% of spinal metastases, and has not previously been reported for chondrosarcoma.

Adult↗