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Biomedical subjects

F A Mann

Publications and source records attributed to F A Mann.

At least 91 records · Page 5Linked to original sources
PubMed1992

Radiographic evaluation of the wrist: what does the hand surgeon want to know?

Congenital, developmental, and acquired wrist deformities predispose patients to characteristic conditions and their associated debilities. The accurate recognition and quantitation of these conditions represent guideposts to treatment and prognosis. The authors present mensuration methods and normal ranges for the important morphologic features of carpal height, ulnar variance, radial inclination, radial length, palmar tilt, and radial shift. These measurements assume importance in the description and quantitation of many conditions. The authors review the radiographic features and diagnosis of dissociated and nondissociated carpal instability, scapholunate advanced collapse, ulnar translocation, ulnocarpal impaction, and ulnoradial impingement.

Female↗
PubMed1992

Treatment of acutely infected arthroplasties with incision, drainage, and local antibiotics delivered via an implantable pump.

Twelve patients with acutely (symptomatic less than ten weeks) infected arthroplasties were treated with minimal debridement and intraarticular antibiotic, amikacin, delivered via an implantable pump. The infection was suppressed in ten cases. Intraarticular levels of amikacin were obtained in eight cases. These levels ranged from greater than 150 micrograms/ml to 1688 micrograms/ml. The systemic level of amikacin remained below 10 micrograms/ml in all but one case. Duration of hospitalization averaged 19 days. There were no significant toxic side effects to amikacin.

Acute Disease↗
PubMed1992

Comparison of intranasal and intratracheal oxygen administration in healthy awake dogs.

Intranasal (IN) and intratracheal (IT) oxygen administration techniques were compared by measuring inspired oxygen concentrations (FIO2) and partial pressures of arterial oxygen (PaO2) in 5 healthy dogs at various IN (50, 100, 150, and 200 ml/kg of body weight/min) and IT (10, 25, 50, 100, 150, 200, and 250 ml/kg/min) oxygen flow rates. Intratracheal administration of oxygen permitted lower oxygen flow rates than IN administration. Each IT oxygen flow rate produced significantly higher FIO2 and PaO2 than the corresponding IN flow rate. An IT oxygen flow rate of 25 ml/kg/min produced FIO2 and PaO2 values equivalent to those produced by an IN oxygen flow rate of 50 ml/kg/min. An IT oxygen flow rate of 50 ml/kg/min produced FIO2 and PaO2 values equivalent to those produced by IN oxygen flow rates of 100 and 150 ml/kg/min. All IT oxygen flow rates greater than or equal to 100 ml/kg/min produced FIO2 and PaO2 values that were greater than FIO2 and PaO2 values produced by IN oxygen flow rates of 200 ml/kg/min. The lowest flow rates studied (50 ml/kg/min, IN, and 10 ml/kg/min, IT) produced PaO2 capable of maintaining 97% hemoglobin saturation, which should be adequate for most clinical situations. Arterial blood gas analysis and FIO2 measurements are necessary to accurately guide oxygen flow adjustments to achieve the desired PaO2 and to prevent oxygen toxicity produced by excessive FIO2.

Administration, Intranasal↗
PubMed1991

Quality assessment in an ambulatory care unit: do training and responsibility conflict?

The authors determined the characteristics of musculoskeletal radiographic misinterpretations by 2nd-year internal medicine residents (IMRs) and board-certified emergency department physicians (EDPs) in an ambulatory care unit (ACU) compared with interpretations rendered by staff radiologists. The type (false-positive error [F+] or false-negative error [F-]), site, nature, and clinical significance of errors were assessed. Two hundred thirty-three cases met study requirements; EDPs interpreted 165 cases; IMRs, 68. Discrepancies were found in 55 cases (24%) (44 F- and 11 F+). IMRs committed more F- than did EDPs (25% vs 16%). The most common sites of examination were ankle, finger, and elbow. IMRs missed more periarticular fractures (75%) than did EDPs (33%). The errors were judged "clinically significant" in 7.8% of cases; IMRs made more of these errors than did EDPs (13% vs 4%). Radiologist overview reduced clinically significant errors fivefold. The authors conclude that patient care is well served by clinician-radiologist synergism. The inclusion of selected basic radiologic principles in ACU residency training programs may improve non-radiologists' effective use and interpretation of radiologic examinations.

Adolescent↗
PubMed1991

Unidirectional joint communications in wrist arthrography: an evaluation of 250 cases.

Although arthrographically demonstrable communications between various compartments of the wrist occur in older persons without symptoms, similar communications in younger persons may indicate clinically significant posttraumatic ligament tears and other pathologic processes. However, detection of communications varies depending on the arthrographic technique used. It has been claimed that if triple-compartment arthrography is not used in all patients, clinically significant unidirectional ligament tears may be overlooked. We determined the frequency and distribution of unidirectional intercompartmental communications, using a modification of techniques described in the literature. Separate injections of contrast material were made in sequence into the midcarpal, distal radioulnar, and radiocarpal joints of 250 consecutive patients. We found 38 unidirectional communications (17 lunotriquetral, nine scapholunate, three radial capsular, one ulnar capsular, six combined sites, and two indeterminate sites) between the midcarpal and radiocarpal joints. Nine unidirectional communications between the radiocarpal and distal radioulnar joints were found. Comparison of these results with the frequency and direction of unidirectional communications reported by others suggests that demonstration of communications depends on specific technical factors, such as which joint is injected first, the amount of contrast material used, and the delay between injections. This dependence on technical factors raises questions about the value of routine three-compartment wrist arthrography.

Adult↗
PubMed1991

Photostimulable phosphor digital radiography of the extremities: diagnostic accuracy compared with conventional radiography.

A direct comparison was made between digital and conventional radiographs to assess the relative accuracy of a photostimulable phosphor digital imaging system in detecting and localizing minor trauma in the extremities. Matched sets of images were obtained on 103 patients who came to the emergency department for radiographs of the hand, wrist, foot, or ankle. One set was obtained with a conventional screen/film system. The other set was obtained with photostimulable phosphor digital cassettes. The two sets of images of each patient were independently interpreted by three radiologists in a blinded fashion. The findings of each of these three readers were compared with the consensus opinion of two different radiologists. Receiver-operating-characteristic (ROC) curves were plotted for each of the three readers, areas under the curves were calculated, and true-positive fractions were determined at false-positive fractions of 0.1. Although no significant differences in the areas under the ROC curves for the two imaging systems were detected, conventional radiography showed a slight advantage. However, when true-positive fractions for fracture detection were compared at false-positive fractions of 0.1 a statistically significant difference was shown, with conventional screen/film radiography being more sensitive. This study raises questions about the use of currently available photostimulable phosphor systems for imaging trauma of the extremities and suggests that those systems should not be used exclusively.

Adult↗
PubMed1990

Magnetic resonance imaging of peripheral nerve sheath tumors. Assessment by numerical visual fuzzy cluster analysis.

A retrospective, nonblinded review of ten nerve sheath tumors (four malignant) selected for pathologic proof and complete magnetic resonance (MR) evaluation was performed to assess the primary tumor location, signal pattern, and extent of reactive zone. A modification of visual fuzzy cluster analysis (VFCA) that emphasized the number of visual fuzzy clusters in each mass was developed to assess the neural tumors. The MR findings were correlated with the findings at surgery and histopathology. There were six men and four women, aged 19 to 62 years (mean, 43). Nine tumors involved the lower extremity. In all tumors, MRI correctly identified the nerve trunk of origin. Tumor dimensions were generally overestimated by MRI. Three internal signal patterns were observed: homogeneous (1/1 benign), finitely inhomogeneous (5/5 benign), and hectically inhomogeneous (4/4 malignant). The number of visual fuzzy clusters (VFCRs) for each sequence did not allow reliable separation of benign and malignant entities, but when considered in aggregate, benign and malignant lesions segregated in different clusters. This implies that the likelihood of malignancy increases as the number of MR-identifiable tissue types per lesion increase. Three types of reaction (edema) were observed best on long repetition time/echo time (TR/TE) sequences, confined to immediate peritumoral region, intracompartmental, and extracompartmental. The first two patterns correlated well with clinicopathologic findings; however, the third pattern did not. Separation of indolent (benign) cellular masses from aggressive (malignant) ones by MR characteristics is difficult but VFCA shows promise for aiding this differentiation and deserves further investigation in larger study populations.

Adult↗
PubMed1990

Imaging the symptomatic wrist.

1. Imaging studies are useful adjuncts to clinical evaluation. 2. Conventional radiographs remain the keystone of the imaging evaluation of wrist disorders owing to their broad survey capabilities and cost-effectiveness. 3. CT and MRI are excellent to delineate process extent and to improve lesion characterization. 4. MRI and nuclear medicine provide for greater sensitivity for detection and activity of disease, but at a cost of less specificity and greater expense.

Algorithms↗
PubMed1989

Serum testosterone and estradiol 17-beta concentrations in 15 dogs with perineal hernia.

Serum testosterone and estradiol 17-beta concentrations, and serum testosterone-to-estradiol ratio were evaluated in 15 dogs (greater than or equal to 5 years old) with perineal hernia (9 sexually intact males and 6 castrated males) and in 9 clinically normal sexually intact male dogs greater than or equal to 5 years old. There was no significant difference in serum testosterone-to-estradiol ratio between sexually intact male dogs with perineal hernia and clinically normal sexually intact male dogs. In castrated dogs with perineal hernia, serum testosterone concentration and testosterone-to-estradiol ratio were significantly (P less than 0.05) lower, compared with those values in sexually intact dogs with perineal hernia and in clinically normal sexually intact male dogs. There was no significant difference in serum estradiol 17-beta concentration among sexually intact male dogs with perineal hernia, castrated dogs with perineal hernia, and clinically normal sexually intact male dogs. Serum testosterone and estradiol 17-beta concentrations in dogs with perineal hernia did not differ from those values in clinically normal male dogs of the same age. Castration cannot be recommended for the treatment of perineal hernia unless a castration-responsive contributing factor such as prostatomegaly is identified, unless the pelvic diaphragm of dogs with perineal hernia has high sensitivity to normal or low serum testosterone and estradiol 17-beta concentrations, or unless there is documentation that other androgens and/or estrogens are involved.

Animals↗
PubMed1989

Bone healing.

Bone is a tissue composed of organic (cells and matrix) and inorganic (mineral) components. When the mechanical strength of bone is exceeded, fracture occurs. Healing progresses through inflammatory, reparative, and remodeling phases similar to other tissues, but, unlike other tissues, bone possesses the unique capability to completely regenerate and return to pre-injury strength. The bone healing process is influenced by many factors, including mechanical stress, biochemical mediators, bioelectric and piezoelectric properties, and neural and endocrine influences. In short, any factor capable of altering the metabolism of osteogenic cells can influence bone healing.

Animals↗
PubMed1988

Knee ligament reconstruction: plain film analysis.

New concepts in knee ligament reconstruction have recently emerged, significantly improving the success of surgical reconstruction of anterior and posterior cruciate ligaments, using high-strength bone-patellar tendon-bone grafts, as well as medial and lateral collateral soft-tissue ligament reconstructions. We reviewed plain radiographs of 50 patients with a total of 72 ligament reconstructions to determine radiographic signs of complications. A major early complication relates to reconstructed ligament positioning. Isometric positioning of the reconstruction is important for all ligaments, but it is most crucial for the femoral portion of the anterior cruciate ligament. Three cases of nonisometric ligament positioning were identified, two anterior cruciate ligaments and one medial collateral ligament. Another early complication is graft fracture, identified in two cases of anterior cruciate ligament reconstruction. Hardware failure did not occur in this series. Late complications include motion of the graft (none in this series) and patellar fracture (one case in this series). Effusions resolved by 4 weeks in 92% of the cases. However, prolonged effusions are usually sterile and should not be mistakenly diagnosed as representing a septic joint if they are an isolated finding. Nonunion of the graft within its osseous tunnel is unusual. Union occurred in 79% of cases by 6 weeks and in 95% of cases by 5 months. Osseous tunnel sclerosis alone is not considered a complication. We conclude that postoperative plain film radiography is important for assessment of graft and hardware position as well as for the detection of early and late surgical complications.

Adolescent↗
PubMed1987

Effects of improved contrast on lung-nodule detection. A clinical ROC study.

We evaluated the effects of unsharp masking and highly efficient scatter rejection on film-screen chest radiographs of cancer patients. Unsharp masking significantly improved the detectability of lung nodules and visibility of anatomic structures in poorly penetrated areas of the chest. Highly efficient scatter rejection by an improved antiscatter grid provided only modest additional benefits. The study supports the conclusion that nodule detection in poorly penetrated areas on conventional chest radiographs is limited primarily by display contrast, whereas in the well-penetrated lung fields it is limited primarily by confusing background structures, rather than inadequate contrast. A method for analyzing clinical nodule detection data by transforming the FROC data to ROC coordinates also is demonstrated.

Humans↗
PubMed1986

Comparison of metrizamide and iohexol for cisternal myelographic examination of dogs.

A double-blind study, using metrizamide, iohexol, or Ringer's solution (control) as cisternal myelographic agents, was performed on 25 dogs. Before myelographic examination was done, each dog was subjected to physical, clinical pathologic, and neurologic examinations, as well as examinations by electroencephalography and computerized tomography. These were repeated 24 hours after completion of the myelographic examination. The group of dogs given metrizamide (group II) had a significantly greater occurrence of seizure activity (6 of 10) than did the control dogs (group I; 0 of 5) or dogs given iohexol (group III; 0 of 10; P less than 0.003). In group II, the CSF microprotein concentration was significantly greater 24 hours after myelography was done than were the values in groups I and III (P less than 0.003). Myelograms of the group II dogs (metrizamide) and group III dogs (iohexol) had similar diagnostic qualities. At 24 hours after myelographic examination was done, computerized tomography scan revealed that each dog given metrizamide and iohexol had myelographic contrast material in the brain and cervical spinal cord parenchyma. Seemingly, iohexol has good diagnostic quality, but is less epileptogenic than metrizamide when used in cervical myelographic examinations of dogs.

Animals↗