Biomedical subjects

C Hughes

Publications and source records attributed to C Hughes.

316 records · Page 18Linked to original sources

PubMedDate not supplied

N-way sensitivity analysis: a verification and stability-assessment technique for completely subjective decision analysis trees.

The purpose of this paper is to describe the development of N-way sensitivity analysis, a modified version of traditional sensitivity analysis that was created for the purpose of verifying the stability of decisions made by a completely subjective decision-analytic tree. The technique was developed during research that addressed whether nurses make clinical decisions that coincide with those recommended by a decision-analytic model. Since all parameters of the model were derived from subjective assessment, traditional one-way or two-way sensitivity analysis was deemed inappropriate. Consequently, N-way sensitivity analysis was developed and used for the verification of the decision model's results.

Analysis of Variance↗

PubMedDate not supplied

An explanation for various rectus femoris strain injuries using previously undescribed muscle architecture.

We performed cadaveric dissection of the rectus femoris muscle to correlate the various lesions of strain injury seen with imaging studies to the muscular anatomy. The proximal tendon is composed of a superficial, anterior portion from the direct head, and a deep intramuscular portion from the indirect head. The muscle fibers arising from the anterior superficial tendon of the direct head travel in a posterior and distal direction to insert on the posterior tendon of insertion, giving the proximal muscle a unipennate architecture. Muscle fibers from the intramuscular tendon of the indirect head originate on both the medial and lateral sides of the tendon and insert on the distal posterior tendon to create its bipennate structure. Three chronic strain injuries involving the midmuscle belly substance were explored grossly and microscopically. It appears that one type of acute strain injury occurs in the midmuscle belly with disruption of the muscle-tendon junction of the intramuscular tendon resulting in local hemorrhage and edema. More chronically, this hematoma organizes into a fatty, loose connective tissue encasement of the deep intramuscular proximal tendon. Serous fluid from the hematoma may remain within the connective tissue sheath, creating a pseudocyst with the deep intramuscular tendon of the indirect head at its center. The muscle's anatomy helps to explain a different rectus femoris strain injury.

Athletic Injuries↗

PubMedDate not supplied

Incomplete, intrasubstance strain injuries of the rectus femoris muscle.

Rectus femoris muscle strain injuries commonly occur at the distal muscle-tendon junction of the quadriceps tendon. However, we have recently recognized a pattern of strain injury that consists of an incomplete intrasubstance tear at the muscle-tendon junction formed by the deep tendon of the muscle's indirect head and those muscle fibers originating from this tendon. These injuries are found more proximally within the thigh than the "classic" distal rectus femoris muscle strain. We reviewed 10 athletes with these intrasubstance tears, all of whom had diagnostic imaging performed using computed tomography or magnetic resonance imaging or both. Two of these patients required surgical intervention. The mechanism of injury usually involved kicking or sprinting. All patients had chronic thigh pain or an anterior thigh mass or both. Physical examination revealed thigh asymmetry and a nontender to mildly tender intrasubstance muscle mass. Magnetic resonance imaging demonstrated abnormal signal intensity centered about the intramuscular tendon of the indirect head of the muscle. Surgical findings included a mass of fibrous scar and fatty tissue encasing the deep tendon. Surgical removal of this fibrous mass appears curative. We contrast this injury from distal strains of the rectus femoris muscle, as well as from soft tissue neoplasms.

Adolescent↗

PubMedDate not supplied

The representation of uncertainty in medical expert systems.

The development of the rule-based expert system has provided important new techniques for the representation of knowledge. However, continued use of this representational scheme has highlighted some of its deficiencies. In particular, many within scientific and non-scientific fields attempting to use the rule-base design to describe natural phenomena often find it difficult to represent the complexities of the world as 'absolute' rules. For this reason, many investigators acknowledge the need to add an uncertainty mechanism to the rule-base construct. Such a facility would allow the quantification of accuracy or strength of association within individual rules Although agreement exists on the need for an uncertainty representation facility, the debate concerning the most appropriate methodology is far from resolved. The purpose of this paper is to provide a review and commentary on the current state of debate over the five most popular candidate uncertainty models: symbolic representation, MYCIN certainty factors, Bayesian, Dempster-Shafer and fuzzy set logic. The advantages and disadvantages of each uncertainty calculi will be presented and assessed with respect to their applicability to the medical expert systems domain.

Bayes Theorem↗

PubMedDate not supplied