Role of the EU commission for pushing the user acceptance of the health telematics applications.
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Attitude to Computers↗
Biomedical subjects
J C Healy
Publications and source records attributed to J C Healy.
A comparison of the microvascular response in the healing wound in the spontaneously hypertensive and non-hypertensive rat.
BACKGROUND: In the Spontaneously Hypertensive Rat (SHR), there is a significantly greater blood flow at the paw but not at the back than in the non-hypertensive Wistar Kyoto (WKY) rat. We wanted to assess the effect of this higher blood flow on wound healing at the paw. MATERIALS AND METHODS: We characterized the microvascular composition of wounds at the back and paw of 9 SHR rats and 10 WKY rats using a quantitative imaging program. Blood flow was compared using laser Doppler technology. RESULTS: The blood flow response to wounding at the back was identical in the SHR and WKY rats. There was an immediate sharp increase in flow at the center of the wound. Blood flow reached a peak at 3 days and then decreased somewhat by day 7, but still remained five-fold higher than the prewound baseline values. There was also a two-fold increase at the back wound perimeter. There were no differences in microvascular composition at the back between the SHR and WKY rats. In contrast, there was an immediate enormous increase in blood flow at paw wound center in the SHR rats. Flow increased to 75 ml/min/100 gm by 24 h then fell back sharply. Blood flow at the paw in the WKY rats changed very little over the 7 days post wounding. At 3 days, the flow was about twice as high in the SHR than in the WKY wound, but, by day 7, flow was similar in the two rat strains. At the SHR wound perimeter, there was a small increase in flow which was sustained through day 7. Although the microvascular composition at the paw wound center was similar in the SHR and WKY rats, there was a notable difference at the paw perimeter. At baseline, there was a slightly greater capillary density in the SHR paw (32 +/- 1 per mm3) than the WKY paw (25 +/- 8 per mm3). At 7 days after wounding, there was a substantial increase in capillary number in the SHR rats (48 +/- 8 per mm3) as compared to baseline (p = 0.05). In contrast, there was no significant difference in capillary number in the WKY paw wound perimeter (20 +/- 3 per mm3) as compared to baseline. CONCLUSIONS: There is a substantial difference in wound blood flow response between the hypertensive and the non-hypertensive rat. At the back, the blood flow effects of wounding are similar, but, at the paw, the SHR rat shows a dramatic transient increase in flow in the early phases of wound healing. There is apparently no capability to upmodulate microvascular resistance in response to increased pressure at this early stage of wound healing. However, within several days, the granulation tissue microvasculature becomes capable of controlling the effects of raised pressure in the SHR rat. In the SHR paw wound perimeter, there are significantly more capillaries than in the WKY rat. It is possible that greater capillary proliferation in the SHR rat results from higher blood flow in the early phase of wounding. The contrast between the WKY rat and the SHR rat serves to further illustrate the complexity of blood flow regulation which occurs during wound healing.
Animals↗
A neural network approach to the diagnosis of morbidity outcomes in trauma care.
This paper introduces the application of artificial neural networks to trauma complications assessment. The potential financial benefits of improving on trauma center diagnostic specificity in complications assessment are illustrated and the operational feasibility of the use of diagnostic neural models across institutions is discussed. A prototype neural network model is described, which, after training, succeeds in diagnosing the complication of sepsis in victims of traumatic blunt injury. Its diagnostic performance with 100% sensitivity and 96.5% specificity is accomplished with test data from a regional trauma center. The model is further shown to have correctly detected, during training, incorrectly coded data. The potential this suggests, for parsimonious database scrubbing through the use of neural network models, is discussed.
Computer Simulation↗
A comparison of the cutaneous microvascular properties of the spontaneously hypertensive rat and the Wistar-Kyoto rat.
The Spontaneously Hypertensive rat (SHR) and its non-hypertensive companion strain, the Wistar-Kyoto (WKY) rat, provide an excellent comparative model to permit study of the differential properties of cutaneous microvascular beds. We explored the possibility that chronically elevated vascular pressures in the SHR rat might affect the microvascular constitution of the skin. We measured skin blood flow at the back and at the paw of a group of 20-week-old WKY rats and a contrast group of SHR rats. We then performed skin biopsies at these two locations and used the NIH Image program to count and measure the size of capillaries, arterioles, and venules. We also determined microvascular density as percentage of total tissue area. At basal temperature, skin blood flow was similar in the two rat strains at both the back and paw. Heat induced vasodilatation resulted in a 50% increase in blood flow at the back, reaching the same level in the two rat groups. However, at the paw site, thermal stimulation resulted in significantly greater flow (39.3 +/- 3.1 ml/100 gm tissue per min) in the SHR rats than the WKY rats (28.6 +/- 1.9 ml/100 gm tissue per min, P < 0.05). The ratio of systemic arterial pressure to skin blood flow was computed as an index of vascular resistance to flow. At basal temperature, this index was 50% greater for the SHR rats at both skin sites. At 44 degrees C, the resistance index decreased at both sites in both rat groups but was still approximately 50% higher at the back of the SHR than the WKY rats. In contrast, the resistance index at 44 degrees C at the paw site fell to the same level in both the SHR and WKY rats. There were twice as many capillaries at the back of the WKY rats than at the back of the SHR rats (9.2 +/- 2.0 per mm2 vs. 4.7 +/- 1.2 per mm2, P < 0.05). Expressed as a percentage of total tissue area, the capillary density at the back in the WKY rats was 0.064 +/- 0.010% as compared to 0.034 +/- 0.008% in the SHR rats (P < 0.05). There were five times more arterioles at the paw compared to the back in both rat groups with no significant difference between the groups. We measured the diameter of the lumen and the thickness of the wall of each arteriole and computed their ratio as an index of possible media hypertrophy. There were minimal differences seen in these parameters between the two rat groups at the back and paw sites. The venular density was significantly higher at the paw than at the back in both rat groups with no significant difference between them. Reduced capillary density at the back of the SHR rats may be a developmental adaptation to high blood pressure. Such a reduction in the pathways of blood flow may help account for increased flow resistance at that site, independent of arteriolar vasoconstriction.
Analysis of Variance↗
Imaging of the painful shoulder.
A variety of imaging techniques are available for evaluating shoulder pathology. The common disorders of impingement, rotator cuff tears, biceps tenosynovitis and instability are discussed along with the role of various imaging modalities in establishing their diagnosis. Plain radiographs can provide useful information particularly with a history of trauma but give limited information on the soft tissue structures around the shoulder. Ultrasound is a useful and inexpensive means of assessing the biceps tendon and rotator cuff but has a number of limitations and varying reports on its accuracy. Computed tomography (CT) is most helpful in the evaluation of shoulder trauma but gives limited information on the soft tissues. When performed with intra-articular contrast, CT can be used to evaluate shoulder instability particularly in cases where magnetic resonance imaging (MRI) is not available or contraindicated. MRI with or without intra-articular contrast is the most accurate imaging modality for evaluating shoulder pathology allowing visualization of the soft tissues that are often the source of pain.
Diagnostic Imaging↗
Thyroid nodular disease after radiotherapy to the neck for childhood Hodgkin's disease.
Patients who receive radiotherapy to the neck are at risk of developing thyroid dysfunction. This prospective study of patients whose treatment for Hodgkin's disease in childhood included radiotherapy to the neck aimed to investigate the incidence and natural history of thyroid dysfunction and the morphological changes of the gland demonstrated on ultrasound. Forty-seven patients were investigated by clinical examination, thyroid function tests and thyroid ultrasound. Only six patients had a clinically detectable abnormality, but 64% had abnormal thyroid function tests. All patients had an abnormal thyroid ultrasound scan and 42% had at least one focal abnormality. A significant association was found between the presence of a focal lesion on ultrasound and young age at radiotherapy, longer follow-up and the length of time that the thyroid-stimulating hormone (TSH) level had been elevated. During follow-up, 65% of patients not on thyroxine developed new focal abnormalities. The longest time interval between radiotherapy and an increase in TSH level was 94 months, and from radiotherapy to the appearance of a focal abnormality on thyroid ultrasound was over 18 years. Three patients were found to have a thyroid carcinoma. These findings indicate the importance of long-term follow-up for patients treated by neck irradiation for Hodgkin's disease in childhood.
Adolescent↗
Imaging of the rotator cuff and biceps tendon.
Several different imaging techniques are available for evaluating the rotator cuff and biceps tendon. The common disorders of impingement, rotator cuff tears and biceps tendonitis are discussed along with the role which the various imaging modalities can play in establishing their diagnosis. Plain radiographs can be helpful particularly with a history of trauma but give limited information on the soft tissues. Ultrasound is a useful and inexpensive means of assessing the rotator cuff and biceps tendon but has a number of limitations and varying reports on its accuracy. Computed tomography (CT) is most helpful in the evaluation of shoulder trauma but gives limited information on the soft tissues. Magnetic resonance imaging (MRI) is an accurate imaging modality for evaluating the rotator cuff and biceps tendon, allowing visualisation of the soft tissues and the adjacent bony structures.
Arm Injuries↗
The microvascular composition of the healing wound compared at skin sites with nutritive versus arteriovenous perfusion.
Background. In the rat, there is a significantly greater blood flow response to wounding at the back, a site perfused mainly by small capillaries, than at the paw, which has a much higher density of arterioles and venules. Materials and methods. We characterized the microvascular composition of wounds at the two skin sites in 11 Wistar Kyoto rats using a quantitative imaging program. Blood flow was compared using laser Doppler technology. Results. Prior to wounding, skin blood flow was much greater at the paw (7.1 +/- 0.5 ml 100 g tissue-1 min-1) than at the back (2.1 +/- 0.1 ml 100 g tissue-1 min-1, P < 0.01) at baseline. Seven days after wounding, blood flow both at the center (8.3 +/- 1.4 ml 100 g tissue-1 min-1) and at the perimeter of the back wound (4.1 +/- 0.5 ml 100 g tissue-1 min-1) had increased substantially. In contrast, skin blood flow at the perimeter of the paw wound had increased moderately (12. 7 +/- 2.0 ml 100 g tissue-1 min-1), but there was no change at the center of the wound (6.9 +/- 0.9 ml 100 g tissue-1 min-1). There were three times more microvessels per mm2 at the paw site (39.3 +/- 3.6) than at the back (13.1 +/- 1.5) prior to wounding. The wound granulation tissue was very vascular; the numerical density of vessels was identical at back (166 +/- 9) and at paw (154 +/- 6). Despite the marked increase in blood flow at the perimeter of the back wound, there was no difference in the microvascular density (15. 2 +/- 1.4) compared to baseline, nor was there a difference at the paw perimeter (39.4 +/- 3.6) compared to baseline. Conclusions. This study demonstrates that the microvascular constitutions of granulation tissues at the paw and back are identical. Thus, the rise in flow at the back wound and reduction in flow at the paw wound are entirely consistent with similar microvascular compositions of these two sites. Yet, there is increased flow at the back wound perimeter where there is no significant change in microvascular constitution compared to unwounded skin. Therefore, a microvascular structure no different from that prior to wounding functions very differently after wounding. Clearly vasoregulatory factors impact on the wound to modify flow through the microvascular network.
Animals↗
The relationship of laser-Doppler skin blood flow measurements to the cutaneous microvascular anatomy.
The hairless plantar paw surface of the rat shows high skin blood flow with a substantial response to thermal stimulation. This contrasts with hair-covered areas such as the back, where there is much lower basal flow and thermal response. These properties are similar to the differences seen in humans between skin sites which have a high density of arterioles and venules (AV areas) and sites with predominantly nutritive (NUTR) capillary perfusion. However, there has been no previous study of the microvascular anatomy of rodent skin. We used NIH Image, a quantitative imaging program, to count the capillaries, arterioles, and venules in the skin of the plantar paw surface and the back of 14 Wistar-Kyoto rats. We also used laser-Doppler techniques to determine skin blood flow at these sites. We found significantly more vessels per unit area at the paw. There were twice as many capillaries in the paw (19.6 +/- 2.4 per mm2) compared to the back (9 +/- 1.5 per mm2) (P < 0.001). Similarly, there were three times as many venules (11.8 +/- 1.2 per mm2 vs 3. 48 +/- 0.45 per mm2; P < 0.001). The largest difference was in the number of arterioles (7.76 +/- 0.74 per mm2 vs 0.79 +/- 0.13 per mm2 at the back; P < 0.001). The greater microvascular density at the paw was reflected in a threefold higher basal blood flow (6.6 +/- 0. 44 ml/min/100 g) compared to that in the back (1.99 +/- 0.07 ml/min/100 g) (P < 0.001). Microvascular volume at the back was 0.14 +/- 0.01 x 10(6) RBC/ml in the basal state compared to 0.31 +/- 0.01 x 10(6) RBC/ml at the paw. Thus, the increased number of vessels at the paw resulted in a twofold increase in microvascular volume. The plantar paw surface has considerably more vessels than the back. As might be expected, there is a higher proportion of arterioles and venules compared to capillaries at the paw than at the back. Thus, the plantar paw surface is an AV site compared to the back, which is a NUTR site. Although our prior studies have largely assumed that we could use the paw and back as contrast sites comparable to AV and NUTR sites in humans, we have now for the first time conclusively established this fact. The increased microvascular density at the paw results in higher skin blood flow at this site.
Animals↗
The peritoneum, mesenteries and omenta: normal anatomy and pathological processes.
The peritoneum is the largest and most complexly arranged serous membrane in the body. The potential peritoneal spaces, the peritoneal reflections forming peritoneal ligaments, mesenteries, omenta and the natural flow of peritoneal fluid determine the route of spread of intraperitoneal fluid and, consequently, disease processes within the abdominal cavity. The peritoneal ligaments, mesenteries and omenta also serve as boundaries for disease processes and conduits for disease spread. The peritoneal cavity and its reflections are frequently involved by infectious, inflammatory, neoplastic and traumatic processes. Before the introduction of cross-sectional imaging, the peritoneum and its reflections could only be imaged with difficulty, often requiring invasive techniques. Computed tomography and, to a lesser extent, sonography and MR imaging allow the accurate examination of the complex anatomy of the peritoneal cavity, which is the key to understanding the pathological processes affecting it. This article reviews the normal peritoneal anatomy and its disease processes.
Humans↗
Patterns of prolapse in women with symptoms of pelvic floor weakness: magnetic resonance imaging and laparoscopic treatment.
Magnetic resonance imaging represents a new method of imaging the pelvic viscera and pelvic floor musculature. Rapid sequences allow us to perform magnetic resonance imaging dynamically during straining or pelvic floor contraction, which can elegantly demonstrate the patterns of pelvic floor prolapse. The technique is relatively quick, noninvasive, and does not use ionizing radiation. The principle of the laparoscopic approach is to imitate the conventional abdominal or vaginal techniques. Laparoscopic sacrospinous fixation or sacral colpopexy using a graft as well as the laparoscopic repair of enteroceles and rectoceles may offer some advantages over the classic approach. As comparative prospective studies are still missing, the role of laparoscopy in the management of pelvic floor defects remains to be defined.
Female↗
Magnetic resonance imaging of fistula-in-ano: STIR or SPIR?
Patients with clinically suspected anorectal sepsis were studied using MRI in order to determine if T2 weighted sequences with fat suppression conveyed any additional benefit over conventional short tau inversion recovery (STIR) sequences. 23 consecutive patients (16 male) undergoing MRI for suspected perianal sepsis were studied prospectively using a 1.0 T whole body system and body coil. Axial and coronal T1 weighted turbo spin echo sequences were obtained, followed by STIR and T2 weighted spectral fat saturation inversion recovery (SPIR) sequences. Images were assessed for the presence of sepsis or fistula, and information provided by the sequences compared. Active disease was diagnosed in 17 patients, 14 of whom had fistula-in-ano; one intersphincteric, 10 transsphincteric and three extrasphincteric. Internal openings were identified in all of these 14 patients; anal in 10, rectal in two, and both in two. Diagnosis and fistula classification was possible in all of these 14 subjects on the basis of STIR sequences alone. The anal sphincters and pelvic floor musculature were better resolved by STIR than SPIR, leading to easier and more confident determination of fistula anatomy in eight of the 14 (57%). In no case did STIR sequences fail to resolve inflammation seen subsequently on SPIR, despite reduced track intensity. T1 weighted sequences were generally non-contributory. Both STIR and SPIR sequences are adequate to classify fistula-in-ano, but classification was easier with STIR due to superior resolution of pelvic floor structures.
Abscess↗
Cystic islet cell tumors of the pancreas.
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Adenoma, Islet Cell↗
The skin blood flow response in wound healing.
Although vasodilation is conventionally held to be the predominant microvascular response to a wound, there has been no previous attempt to actually quantitate skin blood flow within and in the neighborhood of wounds. In particular, there has been no differentiation between sites with primarily nutritive (NUTR) blood flow and those with considerable arteriovenous (AV) perfusion. We used our previously described model of cutaneous blood flow in the rat to study the blood flow response to wounding. We measured skin blood flow at the centers and at the undisturbed perimeters of wounds placed at the back, a NUTR site, and at the paw, an AV site, in 11 Wistar Kyoto rats. Measurements were performed at baseline, and then at 3 hr, 24 hr, 72 hr, and 7 days postwounding. At 3 hr, flow at the center of the back wound had increased to 11.3 +/- 1.4 ml/min/100 g from a baseline of 2.1 +/- 0.1 ml/min/100 g and remained elevated at 7 days (8.3 ml/min/100 g). Flow at the perimeter of the back wound rose as well, but not as high as at wound center, to twice the baseline level (4.1 ml/min/ 100 g at Day 7). Flow values at control sites on the back did not increase from baseline. Flow at the center of the paw wound rose from 7.2 +/- 0.5 ml/min/100 g at baseline to 15.6 +/- 4.3 ml/min/100 g at Day 3 but then fell back to 6.9 +/- 0.9 ml/min/100 g at Day 7. There was only a very small increase in the basal temperature wound response at the paw perimeter. Blood flow at all wound sites showed a response to heat. At the back, heating to 44 degrees stimulated an 80% increase in blood flow at baseline. This degree of increase was maintained at both the center and the perimeter of the back wound. In contrast, although there was also a thermal response at the paw wound center, it was of much lower magnitude than the nonwounded baseline response. As a result, the heat-stimulated flow value actually fell over the 7 days to approximately half of the baseline level. At the paw wound periphery, there was an initial fall in the heat stimulated response, but it then recovered to the baseline level and remained stable over the 7 days. Thus, the skin blood flow response seen at the paw wound challenges the conventional concept of vasodilation as the expected wound blood flow response. The mechanisms of blood flow response in the healing wound may be more complex than the simple inflammatory vasodilation conventionally postulated.
Animals↗
Medical informatics training in pathology residency programs.
Computers and information technology are increasingly used by pathologists, necessitating training in such technology in pathology residency programs. We surveyed 176 programs in the United States and Canada to assess informatics training in terms of instructional methods used, computer availability, and type of training offered. Eighty-four programs replied, for a response rate of 48%. Ninety percent of programs reported offering formal informatics training, but only 68% of programs required it. A rotation dedicated to teaching informatics was provided in 24% of the programs; in 44% of programs, informatics was integrated with other rotations. The most common instructional methods used were hands-on experience with microcomputers and the use of tutors. In 94% of programs, computers were available for resident use; in 60%, residents had individual computers assigned to them. Five programs offered a dedicated informatics rotation but did not provide residents with individual computers, and 22 programs required informatics training but did not provide residents with individual computers. Comparison of these data with data from 1993 shows an increase in programs offering (90% vs 84%) or requiring (68% vs 59%) informatics. Fewer programs offer a dedicated rotation (24% vs 31%) or integrate informatics training with other rotations (44% vs 69%). These data suggest that although informatics training is considered important by most training programs, inadequate resources and lack of formal, structured programs may limit training.
Canada↗
Patterns of prolapse in women with symptoms of pelvic floor weakness: assessment with MR imaging.
PURPOSE: To show the magnetic resonance (MR) imaging patterns of prolapse and to correlate them with symptoms in patients with constipation or fecal incontinence. MATERIALS AND METHODS: Thirty women underwent MR imaging with fast spoiled gradient-recalled acquisition in the steady state. The women were divided into three groups: 10 were asymptomatic volunteers, 10 had constipation, and 10 had fecal incontinence. Visceral prolapse and the configuration of the pelvic floor muscles were identified at rest and during straining. Visceral descent was compared between the three groups. RESULTS: Visceral prolapse was seen at multiple sites, most frequently in constipated patients. There was significantly greater bladder base descent (P < .01), uterocervical descent (P < .001), and puborectalis muscle ballooning (P < .05) in the group of constipated patients when compared with the group with fecal incontinence or the asymptomatic group. The degree of anorectal junction descent was significantly greater (P < .05) in the group of incontinent patients when compared with the asymptomatic group. CONCLUSION: MR imaging clearly shows pelvic visceral prolapse and pelvic floor configuration on straining. Prolapse frequently involves multiple sites in constipated patients, which is suggestive of global pelvic floor weakness. In contrast, the weakness is frequently posterior in fecally incontinent patients.
Adult↗
The cost of diagnosis: a comparison of four different strategies in the workup of solitary radiographic lung lesions.
INTRODUCTION: Due to the large numbers of negative results of sputum examinations in the face of malignant disease, we used a decision analytic model to determine whether, and under what conditions, sputum cytology (Spt) might have a cost-effective role to play in the approach to lung lesions. METHODS: We constructed a decision analytic model to compare the utility of Spt, image-directed fine-needle aspiration (FNA), bronchoscopic examination (Bronch), and open biopsy (OBx) in the evaluation of lung lesions. Prevalence and cost data were derived from local databases and diagnosis-related groups. Diagnostic sensitivity (sens) and specificity (spec) of the tests were derived from the literature and local data. Output of the model was lowest cost per correct malignant diagnosis and included surgical treatment costs. We did not attempt to model survival data or morbidity. Sensitivity analyses were performed using cost, test sensitivity, and lesion size variables. RESULTS: In the baseline case, a patient who is a surgical candidate with lesion size 2.8 cm, prevalence of malignancy=0.67, FNA sens=0.95, Bronch sens=0.80, Spt sens=0.51, OBx is the best initial procedure with a cost per correct diagnosis of $12,888. Sputum examination has the highest cost per correct diagnosis of $63,424. FNA and bronchoscopy have cost per correct diagnosis of $21,543 and $16,615, respectively. Sens analysis shows that OBx is the preferred strategy in the workup of lung lesions in patients who are surgical candidates older than 30 years of age. Spt is the preferred strategy only when the patient is not a surgical candidate, the lesion size is large (>4.7 cm), and only if sputum sens is >0.45. CONCLUSIONS: Spt is not cost-effective in clinical practice, except when the patient has a large clinically unresectable lesion and the laboratory can demonstrate sufficient test sens.
Age Factors↗
MR appearances of desmoid tumors in familial adenomatous polyposis.
OBJECTIVE: The purpose of this study was to investigate the ability of MR imaging to show desmoid tumors in patients with familial adenomatous polyposis, to document the appearances of these tumors, and to identify possible predictors of growth. SUBJECTS AND METHODS: CT and MR imaging of 15 patients with familial adenomatous polyposis and known abdominal wall or intraabdominal desmoid tumors were performed. Nine patients underwent follow-up CT and MR imaging, and four patients had undergone CT within the previous 12 months. Unenhanced and gadolinium-enhanced T1-weighted MR imaging sequences and T2-weighted MR imaging sequences were performed, as was unenhanced and IV contrast-enhanced helical CT. The CT and MR images were independently assessed. RESULTS: CT revealed 35 desmoid tumors: 22 were intraabdominal and 13 were in the abdominal wall. MR imaging revealed 21 of the 22 intraabdominal desmoid tumors and 13 of the 13 abdominal wall desmoid tumors. MR imaging and CT findings agreed precisely on the site and margin of the intraabdominal and abdominal wall desmoid tumors. CT was more effective in revealing their relationship to the bowel. Contrast enhancement was more easily identified on MR images than on CT scans, especially when enhancement was inhomogeneous. High signal intensity on T2-weighted images was seen in eight desmoid tumors, all of which showed significant growth on follow-up scans. CONCLUSION: MR imaging can show both intraabdominal and abdominal wall desmoid tumors in patients with familial adenomatous polyposis. High signal intensity on T2-weighted images was seen from desmoid tumors that had shown marked growth on follow-up imaging.
Adenomatous Polyposis Coli↗