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M L Richardson

Publications and source records attributed to M L Richardson.

At least 19 recordsLinked to original sources
PubMed2001

Low-resistance endometrial arterial flow in the exclusion of ectopic pregnancy revisited.

The objective of this study was to evaluate the efficacy of endometrial arterial flow in the exclusion of ectopic pregnancy. From October 1997 to June 1999, 66 women with elevated beta-human chorionic gonadotropin titers and clinical indications of ectopic pregnancy were evaluated by endovaginal sonography. Women with a gestational sac containing an embryo, a yolk sac, or both were excluded from the study. Doppler ultrasonography was performed in the remaining cases when a definite intrauterine pregnancy could not be visualized. In all cases the thermal index was kept to less than 1.0, consistent with as-low-as-reasonably-achievable principles. Trophoblastic flow was defined as a resistive index of less than 0.6 within the endometrium. Statistical analysis was performed using a 2-tailed t test. Twenty women had ectopic pregnancies; 33 had spontaneous pregnancy losses; and 13 had normal intrauterine pregnancies. A total of 29 women had endometrial trophoblastic flow: 11 of 13 with intrauterine pregnancies, 1 of 20 with ectopic pregnancies, and 17 of 33 with spontaneous pregnancy losses. The negative predictive value for the presence of endometrial low-resistance flow for excluding ectopic pregnancy was 97%. The presence of low-resistance arterial endometrial flow can be a useful sign in diagnosing an early intrauterine pregnancy and decreasing the probability that an ectopic pregnancy is present, particularly in patients with otherwise normal ultrasonographic findings.

Adult↗
PubMed2000

CT detection of hepatic and splenic injuries: usefulness of liver window settings.

OBJECTIVE: This study was designed to assess the usefulness of liver window settings when performing abdominal CT for the detection and characterization of hepatic and splenic injuries. SUBJECTS AND METHODS: We prospectively evaluated helical abdominal CT scans for hepatic and splenic injuries in 300 consecutive patients with blunt abdominal trauma over a 4-month period. There were 204 males and 96 females with a mean age of 34 years (age range, 1-87 years). For each patient, initial CT diagnosis of hepatic or splenic injury was made from images obtained with standard abdominal window settings. CT scans were then immediately reinterpreted using additional images obtained at narrow window width (liver windows). Changes in conspicuity and characterization of injury were recorded. All CT examinations were performed with helical 7-mm collimation at a pitch of 1.5 after oral ingestion of diluted barium and during bolus IV administration of 125 mL of ioversol at a rate of 2-3 mL/sec. RESULTS: We detected hepatic or splenic injuries in 34 patients (11.3%). There were 19 hepatic injuries and 18 splenic injuries. Three patients had injuries to both liver and spleen. Conspicuity of hepatic or splenic injuries was mildly increased (+1 H) on liver windows in 16 patients, whereas the injury was equally conspicuous on both liver window and standard window images in 19 cases. In no case did review of the liver windows result in a change in grade of injury or reveal an injury that was not seen on standard abdominal window images. The total increased cost for printing liver windows was $5748. CONCLUSION: Routine use of liver window settings for abdominal CT in trauma patients has little clinical usefulness and is not cost-effective.

Abdominal Injuries↗
PubMed1998

Lung-volume reduction surgery for diffuse emphysema: radiologic assessment of changes in thoracic dimensions.

Patients with severe, diffuse emphysema may be candidates for pneumectomy (lung-volume reduction surgery, LVRS) to improve lung and respiratory muscle function. To identify candidates who might benefit from this surgery, it is necessary to understand how lung volumes and respiratory function are effected. In this article, the authors demonstrate a significant difference in lung size on chest radiographs obtained before and after surgery. Thirty-five of 71 consecutive patients undergoing LVRS had both preoperative and postoperative chest radiographs and pulmonary function tests available for retrospective review. Preoperative and postoperative measurements of lung height, transthoracic diameters, mediastinal width, heart size, diaphragmatic arc, and intercostal spaces were compared using paired t-tests. Radiographic measurements where also correlated with changes in lung volumes as measured by pulmonary function tests. Lung heights (right, left, mean lateral) and coronal diameter at the aortic arch were reduced after surgery (all p < 0.05). Forced vital capacity, forced expiratory volume in 1 second (FEV1), and vital capacity increased, and total lung capacity and residual volume decreased after surgery (all p < 0.05). Left lung height showed a significant correlation (p = 0.025) with FEV1; all other correlations between radiographic changes and pulmonary function test changes were not significant. The explanation for improved lung function in patients after LVRS is not completely clear and is probably multifactorial. Radiologic alterations reflect anatomic changes caused by surgery and support the theory that modifications of chest wall configuration occur and are likely responsible, in part, for improved symptomatology and respiratory function.

Adult↗
PubMed1997

The physician executive: role in the adaptation of American medicine.

In the arena of managed care and large delivery systems, professional associations find it increasingly difficult to influence the environments in which their members practice. Physician executives appear likely to play key roles in the response of medicine to change. This article discusses how an analysis of the work of physicians involved in management fails to yield a clear analytic distinction between physicians engaged in management and the behavior of others who have managerial responsibility.

Health Care Reform↗
PubMed1997

On-line delivery of continuing medical education over the World-Wide Web: an on-line needs assessment.

OBJECTIVE: On-line continuing medical education (CME) courses offer at least two potential advantages: They are extremely convenient and relatively inexpensive. Before expanding our department's 2-year-old on-line category 1 accredited CME program, we conducted a survey to assess the need for more courses of this type and to document those topics of most interest to our responders. MATERIALS AND METHODS: An on-line survey form was designed and linked to the home page of our departmental Web server. The 8-month survey asked whether responders were interested in earning category 1 CME hours, how many hours they desired, how much they were willing to pay for each hour, and which topics would interest them most. Responders were also asked to specify their medical practice and medical specialty. All responses were tabulated, and simple descriptive statistics were calculated. RESULTS: Our survey received 317 responses: 188 from physicians, 42 from radiology technologists, 11 from physician assistants and nurse practitioners, and the remainder from 26 other categories of practice. Physician specialties identified included 86 diagnostic radiologists, 24 internists, 18 emergency medicine specialists, 15 family practitioners, and 45 from 14 other specialties. Responses came mainly from the United States; however, 32 responses were received from 15 other countries. The median number of on-line CME hours desired was 15 (range, 1-1324). Physician responders were willing to pay a median amount of $10 per credit hour (range, $0-400). The most commonly suggested topic was general radiology, followed by general reviews of MR imaging, CT, sonography, and various organ-based specialties in radiology such as mammography, neuroradiology, and musculoskeletal radiology. CONCLUSION: Physicians and many other health care workers are interested in on-line CME and are willing to pay for such a service. This information, as well as the suggested topics collected in this survey, may prove helpful in planning future offerings of on-line CME.

Attitude of Health Personnel↗
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↗