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Biomedical subjects

M L Richardson

Publications and source records attributed to M L Richardson.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1992

Parasites and condition of coexisting populations of white-tailed and exotic deer in south-central Texas.

We examined the parasites and physical condition of coexisting white-tailed deer (Odocoileus virginianus), axis deer (Axis axis), fallow deer (Dama dama), and sika deer (Cervus nippon) on the YO Ranch (Kerr County, Texas, USA) during December 1982 to January 1984. White-tailed deer harbored 12 species of parasites. Exotic deer were infected with nine species of parasites. All parasites recovered from exotic deer and white-tailed deer have been reported from white-tailed deer. Exotic deer had higher condition ratings than white-tailed deer.

Animal Nutritional Physiological Phenomena↗
PubMed1991

Gallstone susceptibility to in vitro fragmentation by a 480-nm pulsed dye laser. Correlation with computed tomography characteristics.

The object of this investigation was to determine gallstone susceptibility to laser lithotripsy and to discover whether this susceptibility is related to the computed tomography (CT) appearance of gallstones. Gallstones collected from surgery were scanned by CT and classified as homogeneously dense (greater than 90 Hounsfield units [HU]), homogeneously faint (30-60 HU), or rimmed. Sixty stones were subjected to laser energy at 20, 40, 60, 80, or 100 mJ. Fracture and fragmentation (all particles less than 2 mm) were assessed in relation to the energy level setting and number of laser pulses delivered. The authors found that a 480-nm, flashlamp-pumped pulsed dye laser can fragment completely all the types of human gallstones that were tested, although there is significant variability in gallstone susceptibility to laser lithotripsy. This susceptibility varies with CT appearance: dense stones require fewer pulses and lower energies for fracture and fragmentation, compared to faint or rimmed stones. The authors anticipate that CT characterization of gallstones may be a clinically useful screening tool before laser lithotripsy.

Cholelithiasis↗
PubMed1991

Comparison of STIR and spin-echo MR imaging at 1.5 T in 45 suspected extremity tumors: lesion conspicuity and extent.

Short inversion time inversion recovery (STIR) imaging and a double-echo spin-echo (SE) sequence at 1.5 T in 45 sequential patients with suspected extremity tumors were compared to assess the number of lesions detected, subjective conspicuity of lesions, approximate volume of abnormality detected in each lesion, and identification of peritumoral brightening in tissues adjacent to each lesion. STIR sequences enabled detection of all 45 lesions; 44 were detected with the SE sequence. Tumor appeared most conspicuous on STIR images in 35 patients (78%) and was most conspicuous on SE images in 10 patients (22%). Peritumoral brightening, which indicated either peritumoral edema or microscopic tumor infiltration, was detected in 20 patients but was detected only with STIR sequences in nine patients. It is concluded that, although STIR and SE sequences are comparable for lesion detection in the extremities, most lesions appear more conspicuous with STIR. STIR may enable detection of a greater volume of abnormality than SE sequences and may therefore have important implications for local staging and surgical and radiation therapy planning.

Adolescent↗
PubMed1991

Assessment of normal and abnormal erectile function: color Doppler flow sonography versus conventional techniques.

The penile arteries were studied with color Doppler flow sonography in 10 subjects with normal and 39 patients with abnormal erectile function. The relationships of systolic and diastolic velocities to spectral waveform changes in the penile arteries in response to tumescence were studied before and after intracorporal injection of vasoactive medications that induce erection. In normal subjects, a characteristic spectral waveform pattern corresponded to increasing intracorporal pressure. Patients with abnormal arterial inflow and/or abnormal venous sinusoidal leakage demonstrated deviation from the patterns noted in normal subjects. Patients with abnormal arterial inflow had lower mean peak systolic velocities than normal subjects. Patients with severe venous sinusoidal incompetence had an arrest of waveform progression with evolution to but not beyond phases 1 or 2 (diastolic flow remained positive). Patients with abnormal arterial inflow and abnormal venous sinusoidal outflow had waveform changes that reflected both processes. Systolic/diastolic velocity and waveform relationships can be used to define the integrity of both the cavernosal artery inflow and venous sinusoidal outflow occlusion mechanisms.

Adult↗
PubMed1991

Effect of patient positioning after needle aspiration lung biopsy.

Fifty-five patients who underwent fluoroscopically guided needle aspiration lung biopsy were randomly assigned to one of two postbiopsy treatment groups: Patients were placed recumbent with puncture site either down (n = 36) or up (n = 19) for at least 1 hour. No significant difference in pneumothorax rate was seen between the two groups. Chest tube placement, however, was required in 21% (four of 19) of the puncture-site-up group versus 3% (one of 36) of the puncture-site-down group, which was a significant difference (P = .04). Puncture-site-down postbiopsy positioning reduces the proportion of patients requiring chest tube placement after lung biopsy.

Biopsy, Needle↗
PubMed1991

Repairs of the rotator cuff. Correlation of functional results with integrity of the cuff.

We evaluated the results of 105 operative repairs of tears of the rotator cuff of the shoulder in eighty-nine patients at an average of five years postoperatively. We correlated the functional result with the integrity of the cuff, as determined by ultrasonography. Eighty per cent of the repairs of a tear involving only the supraspinatus tendon were intact at the time of the most recent follow-up, while more than 50 per cent of the repairs of a tear involving more than the supraspinatus tendon had a recurrent defect. Older patients and patients in whom a larger tear had been repaired had a greater prevalence of recurrent defects. At the time of the most recent follow-up, most of the patients were more comfortable and were satisfied with the result of the repair, even when they had sonographic evidence of a recurrent defect. The shoulders in which the repaired cuff was intact at the time of follow-up had better function during activities of daily living and a better range of active flexion (129 +/- 20 degrees compared with 71 +/- 41 degrees) compared with the shoulders that had a large recurrent defect. Similar correlations were noted for the range of active external and internal rotation and for strength of flexion, abduction, and internal rotation. In the shoulders in which the cuff was not intact, the degree of functional loss was related to the size of the recurrent defect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

A comparison of penile brachial index and angiography: evaluation of corpora cavernosa arterial inflow.

We studied 32 impotent patients with angiography. The penile branchial index was calculated from the maximal penile arterial pressure measured from any penile artery. In 15 of the 32 patients an attempt was made to isolate the cavernous artery pressure (cavernous artery penile brachial index). There was a poor correlation between angiography and penile branchial index (r equals 0.314) and between angiography and cavernous penile brachial index (r equals 0.637). We also evaluated 15 normal individuals and a wide range of penile brachial index values was found (0.7 to 1.0). Penile brachial index values from normal patients overlapped with those from impotent patients. Penile brachial index values from impotent patients with normal and abnormal arteries (as determined by angiography) overlapped. The fact that penile brachial index measurements are performed in the flaccid state and without direct visualization of the cavernous arteries accounts for some of the variability of the penile brachial index test.

Adult↗
PubMed1989

A DPA technique for simultaneously measuring bone, soft tissue, and fat content.

Although conventional dual photon absorptiometry (DPA) techniques can be used to estimate fat and soft tissue content, such estimates are not possible where bone is present. We propose a method that can make these estimates in the presence of bone in the extremities of the body. The combination of this method with the conventional method should yield fat and soft tissue composition from most points within the body. The proposed technique simultaneously measures thicknesses of bone, soft tissue, and fat. These thicknesses are determined of bone, soft tissue, and fat. These thicknesses are determined from a combination of gamma-ray transmission data at two energies and a measurement of total tissue thickness. To test the technique, a feasibility study was performed with known thicknesses of aluminum (simulating bone), lucite (simulating tissue), and polyethylene (simulating fat). A variety of thicknesses of each material were employed (Al: 0-1.3 cm, lucite: 0-5 cm, polyethylene: 0-5 cm). The accuracies (standard errors of the estimates) of the calculated versus true thicknesses of aluminum, lucite, and polyethylene were 0.6%, 2.6%, and 2.5%, respectively. The estimates of "bone" thickness were insensitive to the presence of varying thicknesses of "fat." (In contrast, application of the conventional DPA method to the same gamma-ray transmission data yielded underestimates in "bone" thickness due to "fat" by as much as 11%.) For a 60 minute (whole body) scan time, the reproducibility of the measurements of the thicknesses of aluminum, lucite, and polyethylene were 0.4%, 1.0%, and 1.3%, respectively. All of these values are in a clinically useful range.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗