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Biomedical subjects

K D Hopper

Publications and source records attributed to K D Hopper.

At least 127 records · Page 7Linked to original sources
PubMed1984

A reevaluation of placental grading and its clinical significance.

Pregnancies complicated by preeclampsia or intrauterine growth retardation have an earlier and faster placental maturation than normal. This is demonstrated in a study of 1,096 obstetrical examinations of 473 non-diabetic mothers. It is recommended that a pregnancy demonstrating grade I maturational changes prior to 27 weeks, grade II changes prior to 32 weeks, or especially grade III changes prior to 34 weeks be followed clinically and ultrasonically for possible complications.

Female↗
PubMed1983

Comparative analysis of ultrasonographic methods of gestational age assessment.

Measurement of crown-rump length (CRL) is widely accepted as the most accurate method of gestational dating. The statistical accuracy of growth-adjusted sonographic age (GASA) determinations has been demonstrated to be similar. Ninety-six patients were prospectively examined by use of serial ultrasonography, and findings were evaluated to correlate CRL with a single biparietal diameter (BPD) obtained between 20 and 24 weeks of gestation, with GASA, and with accurate maternal dates. Growth-adjusted sonographic age was shown to be not as accurate as CRL and no more accurate than a single BPD obtained between 20 and 24 weeks or reliable maternal dates.

Anthropometry↗
PubMedDate not supplied

Multiple fine-needle biopsies using a coaxial technique: efficacy and a comparison of three methods.

PURPOSE: Compare the success of three coaxial fine-needle biopsy techniques in obtaining multiple cytologic specimens of high quality. METHODS: For each of three different biopsy needle and technique combinations (aspiration: 22-gauge Chiba; capillary: 22-gauge Chiba; 22-gauge Autovac aspiration biopsy gun), 30 sites (15 liver, 15 kidney) were selected for coaxial fine-needle biopsy in cadaveric liver and kidneys. For each coaxial technique, three sequential biopsies were performed through an 18-gauge coaxial needle at each of multiple sites. The quality of the resultant 270 specimens was graded by a blinded cytopathologist using a previously published grading scheme. RESULTS: Using the coaxial technique, there was no significant dropoff in the cytologic specimen quality among the first, second, and third biopsies at a specific site, regardless of the order of the techniques/needles used. This was true for organs, the overall data, and for the individual five grading criteria. There was, however, a significant difference among the biopsy techniques themselves. Though there was no difference in the quality of cytopathologic specimen obtained with the Autovac aspiration gun and the aspiration technique with a 22-gauge Chiba needle, both were statistically better than the nonaspiration, capillary technique utilizing a 22-gauge needle (p = 0.0001). CONCLUSION: The use of a coaxial technique with a fine-needle, 22-gauge biopsy offers unique advantages in obtaining a nearly unlimited amount of high-quality material for cytopathologic analysis. In this study, no dropoff was found in specimen quality with subsequent biopsies.

Biopsy, Needle↗
PubMedDate not supplied

Capillary versus aspiration biopsy: effect of needle size and length on the cytopathological specimen quality.

PURPOSE: To test the value of the nonaspiration, or capillary, biopsy technique by experimental comparison with the conventional fine-needle aspiration technique using various needle gauges and lengths. METHODS: On fresh hepatic and renal tissue from five autopsies, multiple biopsy specimens were taken with 20, 22, and 23-gauge Chiba needles of 5, 10, 15, and 20-cm length, using the aspiration technique and the capillary technique. The resultant specimens were graded on the basis of a grading scheme by a cytopathologist who was blinded to the biopsy technique. RESULTS: The capillary technique obtained less background blood or clot which could obscure diagnostic tissue, although not significantly different from the aspiration technique (p = 0.2). However, for the amount of cellular material obtained, retention of appropriate architecture, and mean score, the capillary technique performed statistically worse than aspiration biopsy (p < 0.01). In addition, with decreasing needle caliber (increasing needle gauge) and increasing length, the capillary biopsy was inferior to the aspiration biopsy. CONCLUSION: The capillary biopsy technique is inferior to the aspiration technique according to our study. When the capillary technique is to be applied, preference should be given to larger caliber, shorter needles.

Biopsy, Needle↗
PubMedDate not supplied

Adaptation of the bard prostate biopsy gun for CT-guided abdominal biopsies.

The Bard prostate biopsy gun under ultrasonic guidance provides consistent, high quality prostatic core samples for histopathologic diagnosis. This device can be adapted for biopsy of abdominal organs using computed tomographic guidance. We demonstrate how these technical modifications can be made. Having used this modified device in conjunction with the 18-gauge prostate biopsy needle in 25 patients, we have had excellent results and no complications.

Abdomen↗
PubMedDate not supplied

Extended pitch thoracic helical CT 47.

The objective of this study was to test whether extended 1.5 pitch helical computed tomography (CT) can be used for routine thoracic CT without a significant loss of clinical scan quality. Thirty consecutive patients presenting for contrast thoracic CT were computer randomized into one of three groups: conventional, 1.0 pitch helical, and 1.5 pitch helical. All other variables, including kV, mA, slice thickness and reconstruction interval, and contrast administration, were kept constant. The studies were randomized to five independent, blinded, experienced radiologists who rated visualization 25 normal structures, and up to five pathologic findings per patient. In addition, each reader evaluated the studies' contrast enhancement, low contrast sensitivity, linear resolution, motion artifact, noise, and overall quality. The visualization score for all normal and overall for pathological lesions did not vary between groups. The three groups were not equivalent for several individual pathologic categories. However, these differences were not consistently in favor of one technique over the other two. The overall score for scan quality was not significantly different between the three groups. Extended 1.5 pitch thoracic helical CT provides equivalent quality versus either 1.0 pitch helical or conventional CT. The use of 1.5 pitch helical thoracic CT allows faster scanning, greater patient coverage, and the use of reduced amounts of intravenous contrast.

Contrast Media↗
PubMedDate not supplied

Utility of low mA 1.5 pitch helical versus conventional high mA abdominal CT.

The objective of this study was to evaluate the utility of a low mA 1.5 pitch helical versus conventional high mA conventional technique in abdominal computed tomography (CT). Twenty-five patients who had both a conventional high mA (> 300) and a 1.5 pitch low mA (80-125) helical CT within 3 months were selected for inclusion in the study. Patients were excluded who had a significant change in pathology between the two studies. The other parameters (injection rate, contrast type and volume, and filming window/level) were constant. The studies were randomized and blinded to five separate experienced readers who graded the studies by a variety of normal anatomical structures and pathological criteria. Overview questions also assessed noise, resolution, contrast, and overall quality. The abdominal wall/retroperitoneum and hiatal hernias were statistically better visualized on the conventional high mA studies. However, for all other normal anatomical and pathological sites, there was equivalent or better visualization on the helical versus the conventional CT examinations. The resolution of the helical studies was graded statistically better than the high mA conventional CT scans as was the amount of noise present on the images. While there was some advantage for conventional high mA CT with respect to contrast enhancement and low contrast sensitivity, these differences were not statistically significant. It appears from the data of this study that a low mA technique in evaluating the abdomen may be a useful option in performing routine abdominal CT. The radiation dose savings to the patient is significant and there appears to be little degradation of image quality using a low mA 1.5 helical versus mA conventional CT technique.

Abdominal Muscles↗
PubMedDate not supplied

Development of a model angiography informed consent form based on a multiinstitutional survey of current forms.

PURPOSE: To develop an informative consent form for angiography that can be read and understood by a patient with an eighth-grade level of education. MATERIALS AND METHODS: Consent forms from 125 medical centers were evaluated with RightWriter 4.0 software. The readability index, a measure of educational grade level needed to understand a document, was determined for each form. Features of forms and discussion of complications were evaluated. A model consent form was developed. RESULTS: Analysis of 27 consent forms revealed a mean readability index of 14.2; to adequately understand the documents, an average of 2.2 years of college were required. Alternatives to the procedure were listed in 14 forms (52%). All consent forms listed potential complications, but only 15 (56%) identified specific numeric risks, and attempts to classify complications according to severity were made in only five (18%). CONCLUSION: An angiography consent form has been developed that can be understood with an eight-grade level of education. It should allow patients to more easily understand the procedure and its risks, benefits, and alternatives. It remains the obligation of the physician to tailor the discussion for each procedure to meet the needs of each patient.

Academic Medical Centers↗
PubMedDate not supplied

The retrorenal colon on computed tomography: a normal variant.

In a review of 200 patients, the position of the colon in relation to the posterior aspect of the kidneys on CT was studied. A small part of the colon was found in the left retrorenal position in 1.0% of the patients. An illustrative case report of an unusual colonic variation in which the colon coursed directly behind the kidneys is described. The anatomy of the retroperitoneal fascia and the significance of the retrorenal colon are discussed.

Colon↗
PubMedDate not supplied

Mammographic and CT detection of extrathoracic lung herniation.

Herniation of lung through the chest wall is uncommon and previously reported cases have been found either clinically or by chest radiography. We recently discovered a case of herniated lung on screening xeromammography. These findings were correlated with thoracic CT.

Female↗
PubMedDate not supplied

The quality of 3D reconstructions from 1.0 and 1.5 pitch helical and conventional CT.

PURPOSE: CT data are commonly used to create 3D images. For this purpose, thin and overlapped slices are desirable. Helical (spiral) CT offers the ability to adjust the slice reconstruction interval from 0 to 100%. However, its use in 1.0 and 1.5 pitch helical CT and 3D imaging, especially with respect to surface detail, is relatively untested. METHODS: Ten objects selected for their varying size, shape, and density were scanned (fourth generation Picker PQ2000) by contiguous 2,4 and 8 mm conventional and helical sequences. The latter were obtained with a pitch of both 1.0 and 1.5 and were reconstructed into a 3D image with 0-75% overlapping of the reconstructed slices. Each of the 24 different sequences per scanned object was reconstructed into identical sets (projections) of 3D images displayed on color film. The 24 3D image sets for each object were submitted to six blinded radiologists who separately ranked them from best to worst. RESULTS: 3D reconstructions obtained from CT scans with a thinner slice thickness, half-field (15 cm FOV), and helical technique were rated as statistically superior. The 1.0 and 1.5 helical sequences obtained with a 4 or 8 mm slice thickness scored statistically better than 3D reconstructions from equivalent conventional scans. Overlapping of the reconstructed helical slices by 25-75% generally improved the quality of the 3D reconstruction. CONCLUSION: Helical CT with either a 1.0 or a 1.5 pitch offers the ability to obtain higher quality 3D reconstructions than from comparable conventional CT scans.

Humans↗
PubMedDate not supplied

The impact of 2D versus 3D quantitation of tumor bulk determination on current methods of assessing response to treatment.

PURPOSE: Measurements from sequential axial "2D" data in cancer patients are commonly used to assess treatment response or disease progression. This study compares the volume of tumor bulk calculated with 3D reconstructions with that calculated by conventional methods to determine if it might change patient classification. METHOD: All medical, gynecologic, and pediatric oncology patients under treatment who were evaluated with serial CT scans between January 1, 1992, and July 31, 1994, for whom the digital data were available were included in this study. For each tumor site, the maximum diameter and its perpendicular were measured and multiplied together to yield an area. The sum of areas of the measured lesions was used as an approximation of overall 2D tumor volume. In addition, the 2D area of each site was multiplied by its height, yielding a 2D volume. Last, the digital data were loaded into a 3D computer system and total 3D tumor volumes determined. All medical and gynecologic oncology patients were treated based upon the 2D area of tumor. The pediatric oncology patients were treated based upon the 2D volume of tumor measured as per standard practice. The members of each treating oncologic service assessed their patients as to how the other two methods would have changed their classification of the patients' response category. RESULTS: Four hundred thirty-three CT scans were performed in 139 patients, which included 204 baseline and 294 follow-up CT examinations. Seventy patients had new tumor foci and would have been classified as failure by all three methods of tumor bulk measurement. The 3D volume versus the 2D area method of tumor bulk assessment would have changed response categories in 52 of the 294 follow-up CT examinations (p < 0.0001). Thirty-five patients were recategorized from either "no response" to "failure" (21 patients) or "no response" to "response" (14 patients) categories. If only those follow-up studies without new metastatic foci are considered, the 3D volume versus the 2D area methods of tumor assessment would have changed the treatment response category in 23.2%. The use of the 2D volume method of calculating tumor volume of bulk tended to overestimate the overall tumor size by an average of 244 cm3 (p = 0.001). CONCLUSION: The 3D method of tumor volume measurement differs significantly from conventional 2D methods of tumor volume determination. Large prospective studies analyzing the usefulness of 3D tumor volume measurements and assessing possible changes in patient response categories would be required for full utilization of this more accurate method of following disease bulk.

Adolescent↗