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Biomedical subjects

K S Shinn

Publications and source records attributed to K S Shinn.

At least 37 records · Page 2Linked to original sources
PubMed1995

Sequential changes of traumatic vertebral compression fracture on MR imaging.

The purpose of this study was to evaluate the sequential signal intensity changes in post-traumatic vertebral compression fractures of varying ages. Sixty-six patients with 115 post-traumatic vertebral compression fractures underwent MR imaging. The ages of fractures at the time of MR images ranged from 1 day to 6 years. Sequential follow-up MR imagings were obtained in 4 patients for 2 years after initial MR examination. The fracture sites in all 52 fractures with traumatic events less than 3 months prior were hypointense on T1-weighted images and hyperintense on T2-weighted images (type I). A type I fracture could be subdivided into 3 patterns depending on its morphologic appearance: diffuse (type Ia); patchy (type Ib); and bandlike (type Ic). In 12 fractures of 3 to 5 months after trauma, six showed focal hypointensity (type II) in all pulse sequences, and six showed isointensity (type IV). Four of 51 fractures with trauma over 5 months showed focal hyperintensity on T1-weighted images and isointensity on T2-weighted images (type III); and the remaining 47 fractures showed isointensity on all sequences (type IV). In conclusion, MR imaging is useful in predicting the age of known traumatic compression fractures, so familiarity with these sequential MR findings would be helpful in distinguishing benign from malignant fractures.

Adult↗
PubMed1994

Radioprotective effect of captopril on the mouse jejunal mucosa.

PURPOSE: Captopril, an inhibitor of angiotensin I converting enzyme, has been shown to modify radiation damage and prevent radiation injury of normal tissue in rats and pigs. The present study was carried out to determine whether captopril would reduce radiation changes in the proximal small bowel in mice. METHODS AND MATERIALS: Mice were subjected to whole body irradiation with 9 Gy or 15 Gy. Captopril was administered in drinking water at a regimen of 62.5 mg/kg/day (captopril group I) and 125 mg/kg/day (captopril group II), continuously from 7 days before irradiation to the end of each designed experiment. The jejunal damage was evaluated microscopically by crypt count per circumference and by histologic damage grading. RESULTS: Crypt number in the sham-irradiated control was 133 +/- 6.8/circumference. In both captopril group I and II, crypt numbers and histologic scores were not significantly different from those in the normal group. The 9 Gy and 15 Gy radiation alone groups showed significantly lower crypt counts and histologic scores compared with the sham-irradiated control group (p < 0.05). The groups exposed to 9 Gy radiation plus captopril I and II showed significantly higher crypt counts and lower histologic damage scores on the third day, and lower histologic damage scores on the fifth day compared with the 9 Gy radiation alone group (p < 0.05). The 15 Gy radiation plus captopril I and II groups had significantly higher crypt counts and lower histologic damage scores on the third day than those of the 15 Gy radiation alone group (p < 0.05). All mice of the 15 Gy radiation group succumbed to intestinal radiation death. CONCLUSION: Our results suggest that captopril provides protection from acute radiation damage to the jejunal mucosa in mice.

Animals↗
PubMed1994

Posterior lumbar apophyseal ring fractures: a report of 20 cases.

Posterior apophyseal ring fracture (PARF) of the lumbar spine is an uncommon injury thought usually to occur in adolescence. We analysed CT findings in 20 cases (19 patients), whose age ranged from 16 to 45 years (average 30 years). The PARF could be divided into two distinct groups on the basis of the shape and location of the fracture and the defect of the vertebral rim. In group 1 (2 cases), PARF involved the central aspect of the inferior vertebral rim and bone fragments were large and broad-based. In group 2, PARF were located at the posterolateral margin of the superior vertebral rim and bone fragments were small and focal. The great majority of previously reported cases belonged to our group 1. A pathogenesis for each group is suggested.

Adolescent↗
PubMed1994

Intussusception: characteristic radiolucencies on the abdominal radiograph.

Six hundred and twenty-five sets of supine and erect abdominal radiographs of 288 patients with the confirmed diagnosis of intussusception (315 episodes) and 310 patients without intussusception were reviewed retrospectively to determine the characteristic radiographic features of intussusception. Among the patients with intussusception, 155 episodes (49%) showed a soft tissue mass and nearly half of these (71) showed characteristic radiolucencies (target, crescentic, or amorphous) in the soft tissue mass. Thirty-five episodes showed the radiolucencies on both the supine and erect radiographs; in 16 cases the type of radiolucency differed on the two films. In patients without intussusception, abnormal radiolucencies were seen in only seven cases (2.3%). Computed tomography performed prospectively in five patients showed the radiolucencies in the soft tissue mass to be intussuscepted mesenteric fat. We conclude that abnormal radiolucencies in the soft tissue mass on plain radiographs are characteristic of intussusception.

Adolescent↗
PubMed1994

1H magnetic resonance spectroscopy characterization of neuronal dysfunction in drug-naive, chronic schizophrenia.

RATIONALE AND OBJECTIVES: We investigated the proton metabolism of right prefrontal white matter in drug-naive, chronic schizophrenic patients (n = 23), compared with healthy normal control subjects (n = 10), by using localized, water-suppressed in vivo 1H magnetic resonance (MR) spectroscopy. METHODS: All 1H MR spectroscopy examinations were performed on a 1.5-T MR imaging/MR spectroscopy system by using a point-resolved spectroscopy pulse sequence for localized volumes of 2 x 2 x 2 cm3. Proton metabolite ratios relative to creatine (Cr) were obtained using a Marquart algorithm. RESULTS: Drug-naive, chronic schizophrenic patients demonstrated a decrease in the N-acetylaspartate (NAA):Cr and choline (Cho):Cr ratios and an increase of the complex of gamma-aminobutyric acid (GABA) and glutamate (Glu)-containing ratio [(GABA + Glu):Cr] as compared with normal control subjects. CONCLUSION: Results suggest that the reduction of NAA and Cho may indicate neuronal dysfunction and that the elevation of GABA and Glu may play a role in chronic schizophrenia. 1H MR spectroscopy may be a useful modality in research and in the clinical evaluation of chronic schizophrenic patients.

Adolescent↗
PubMed1994

Pinhole scintigraphic sign of chondromalacia patellae in older subjects: a prospective assessment with differential diagnosis.

UNLABELLED: Chondromalacia patellae (CP) is an important cause of anterior knee pain. Two clinical types are known: one that typically affects young subjects and the one that affects older patients. The primary diagnostic approach is radiography reinforced with arthrography. A 99mTc-MDP bone scan is invaluable in the study of bone diseases especially when augmented with pinhole scintigraphy (PS). In this study previously unknown, specific sign of CP demonstrated by PS in six middle-aged and elderly patients is described. METHODS: Noting an increased patellar uptake in a planar spot view, a medial PS scan of the patella was taken to detail the uptake pattern using a 3-mm or 4-mm aperture pinhole collimator. The uptake pattern was analyzed in terms of location, definition, mode, grade and other associated changes, and correlated with radiographic and CT scan alterations. RESULTS: The planar views showed patellar uptake to be diffuse and nonlocalizing in five patients and ill-defined and spotty in the remaining patient. In contrast, PS revealed small, spotty uptake well localized in the central retropatellar facet in all but one patient in whom uptake was segmental. A control PS study of 16 patients with their patellas involved by osteoarthritis (n = 6), rheumatic arthritis (n = 5) and Reiter's syndrome (n = 5) also revealed retropatellar uptake with or without anterior patellar uptake in every patient. The CP with localized osteolysis or osteopenia accumulated tracer intensely, whereas those without showed mild to moderate uptake. CONCLUSION: Spotty tracer uptake occurring exclusively in the central retropatellar facet without other knee joint alteration appears pathognomonic of CP in older patients.

Adult↗
PubMed1993

Postnatal growth of fetus-in-fetu.

A 6-month-old-boy who presented with an abdominal mass disclosed a well-formed fetus in the retroperitoneum. This mass was retrospectively noted at the age of 1 month. Comparison of two radiographic examinations done 5 month apart clearly demonstrated the enlargement of an included fetus in the bearer's abdomen. Our report of this rare condition focuses on the growth of the fetus-in-fetu detected by roentgenograms.

Choristoma↗
PubMed1993

Optimisation of dose distribution for linear accelerator-based stereotactic radiosurgery.

The work presented in the paper addresses a method for obtaining the optimal dose distribution for LINAC-based stereotactic radiosurgery. As many targets have nonspherical or irregular shapes and three-dimensional dose calculations included in dose optimisation, long computation times are required to determine the optimum isocentre separation and collimator sizes to shape the irregular target using the multiple-isocentre approach, by trial-and-error types of method. The simple approach, using a computer-aided design optimisation technique and a fast approximate dose model, has been developed to find the optimum isocentre positions and collimator sizes quickly and automatically. A spherical dose model has been developed to represent the dose for a standard arc system with a single isocentre. The implementation of computer-aided design algorithms with the spherical dose model and their application to several cases are discussed. It is shown that the spherical dose model gives dose distribution similar to that of the exact dose model, which makes this simple dose model more efficient, with computer-aided design optimisation, in finding optimum isocentre positions and collimator sizes used in stereotactic radiosurgery.

Humans↗
PubMed1993

Radiologists' responses to patients' inquiries about imaging results. A pilot study on opinions of various groups.

RATIONALE AND OBJECTIVES: The authors analyzed opinions regarding how a radiologist should answer a patient's or patient's family's questions about radiologic results. METHODS: Questionnaires were obtained in a university hospital from 135 physicians of various specialties, including radiologists, and 501 nonphysicians, such as medical students, nurses, patients, families of patients, and hospital personnel. The questionnaire included three questions, each with five choices. The first question concerned a normal result, the second a minor abnormality, and the third a major abnormality. The five choices in each question consisted of two suggestive answers to patients' inquiries and three excuses for the refusal of immediate answers. Respondents were asked to choose the single most desirable and the single least desirable answer. RESULTS: Approximately 50% of all physicians believed that a radiologist should refer the patient to his or her physician rather than to give a suggestive answer to a patient with an abnormality. Considerably fewer physicians had a similar opinion in cases involving a patient with normal results. Patients and the families of patients believed that a radiologist should give at least a suggestive answer in any circumstances where the patient is agitated to know the result. Radiologists were reluctant to convey any information regardless of the test result. CONCLUSIONS: Physicians had significantly different opinions from patients and the families of patients, and radiologists preferred to keep their traditional role of referral physician.

Attitude of Health Personnel↗
PubMed1993

Abdominal actinomycosis: CT findings in 10 patients.

OBJECTIVE: The purpose of this study was to analyze the CT findings in 10 patients with abdominal actinomycosis to determine the appearance of lesions and the pattern of spread of the disease. MATERIALS AND METHODS: We retrospectively reviewed the CT findings in 10 patients with pathologically proved actinomycosis. Involved areas were the pelvis (n = 4), greater omentum (n = 3), liver (n = 2), and kidney (n = 1). Contrast-enhanced (oral and IV) CT scans were available in all patients. Unenhanced CT scans were also available in six patients. RESULTS: CT scans showed mostly solid masses with focal areas of diminished attenuation in seven patients and mostly cystic masses with thickened walls in three. CT findings confirmed the infiltrative nature of the disease, showing its tendency to invade across tissue planes and boundaries. Dense inhomogeneous contrast enhancement in the walls or solid components of masses was seen in eight patients. Minimal lymphadenopathy was seen in only two patients. CONCLUSION: Although nonspecific, actinomycosis should be included in the differential diagnosis when CT scans show an infiltrative mass with unusual aggressiveness and dense inhomogeneous contrast enhancement, especially in patients with fever, leukocytosis, or long-term use of intrauterine contraceptive devices.

Actinomycosis↗
PubMed1993

Local recurrence after surgery for gastric carcinoma: CT findings.

Local recurrence of gastric carcinoma after surgery is defined as histologic evidence of a tumor in the surrounding tissues of the resected stomach. Compared with the large number of articles describing tumor recurrence after colectomy for colonic carcinoma, few reports have been published on the CT findings after gastrectomy. We illustrate the CT features of local tumor recurrence after gastrectomy in 36 patients in whom recurrence was confirmed pathologically or by definitive findings on CT scans.

Adult↗
PubMed1993

Lung abscess. Percutaneous catheter therapy.

Lung abscess was successfully treated with percutaneous drainage in 5 of 6 patients. Complete abscess resolution occurred in 4 patients, partial resolution in one, and no response in one. The duration of drainage ranged from 7 to 18 days (mean 15.5 days) in successful cases. The failure of drainage in one neurologically impaired patient was attributed to persistent aspiration. In 2 patients, concurrent pleural empyema was also cured. CT provided the anatomic details necessary for choosing the puncture site and avoiding puncture of the lung parenchyma. Percutaneous catheter drainage is a safe and effective method for treating lung abscess.

Adolescent↗
PubMed1978

The air meniscus sign in sclerosing hemangioma of the lung.

The air meniscus sign occurs in a number of lung conditions, including infection, benign and malignant tumors, and hematoma. Sclerosing hemangioma does not appear to have been implicated previously in this connection. Two such cases are described. Possible mechanisms of air meniscus formation and its diagnostic value in sclerosing hemangioma are discussed.

Adult↗