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Biomedical subjects

H M Fenlon

Publications and source records attributed to H M Fenlon.

At least 37 records · Page 2Linked to original sources
PubMed1999

Advances in abdominal, aortic, and peripheral contrast-enhanced MR angiography.

This article reviews the basic principles of contrast-enhanced MR angiography, including methods used for sequence optimization and bolus timing, and describes clinical applications of contrast-enhanced MR angiography in the aortic, abdominal, and peripheral arteries. Novel MR angiography imaging techniques also are described, including moving table-top MR angiography, MR fluoroscopy, and time-resolved MR angiography.

Abdomen↗
PubMed1999

Virtual colonoscopy--technique and applications.

Virtual colonoscopy is a new method for evaluating the colon which uses thin section computed tomography of the clean air distended colon. The acquired computed tomography data is then subjected to computer manipulation to demonstrate the colonic mucosa. It is a safe, non-invasive, well-tolerated method that has potential as a method of colorectal cancer screening. This review will describe the technique, review preliminary results, and discuss the present and future applications of this technique.

Colon↗
PubMed1998

Tc-99m tetrofosmin scintigraphy as an adjunct to plain-film mammography in palpable breast lesions.

AIM: To investigate the use of Tc-99m tetrofosmin as a breast imaging agent and to compare results of Tc-99m tetrofosmin scintimammography with plain-film mammography and pathological outcome. PATIENTS AND METHODS: Forty-four patients (mean age, 51 years; range 26-79 years) with a palpable breast mass requiring fine needle aspiration biopsy (FNAB) were prospectively studied. All patients had Tc-99m tetrofosmin scintimammography. Patients over 35 years of age had two view mammography performed on the same day. FNAB was performed within 2 weeks of imaging, and patients referred for surgery as appropriate. Results of scintigraphy and plain-film mammography were correlated with pathological outcome. RESULTS: Of the 44 patients, 21 had biopsy proven malignancy while 23 had benign lesions. Of the 21 patients with carcinoma, 20 (95.2%) had positive Tc-99m tetrofosmin scintimammography while 21 (91.3%) of the 23 patients with benign histology had negative scintigraphy. The sensitivity of scintimammography was 95.24%, the specificity was 91.3%, with a positive predictive value of 90.9% and a negative predictive value of 95.45%. Thirty-eight patients had two view mammography performed (six patients were <35 years of age). Of these 38 patients, 21 had biopsy proven malignancy while 17 had benign histology (all patients <35 years of age had benign histology). Of the 21 patients with malignancy, plain-film mammography was suspicious for malignancy in 17 (81%) while four were reported as benign. Of the 17 with benign disease, 14 patients (82.4%) had benign appearances on plain-film mammography while three (18%) had one or more findings suspicious for malignancy. The sensitivity of plain-film mammography in our group was 81%, with a specificity of 82.4%, a positive predictive value of 85% and a negative predictive value of 77.8%. Tc-99m tetrofosmin scintimammography correctly characterized all seven lesions where mammographic evaluation was limited because of dense breast parenchyma or previous surgery and/or radiotherapy. CONCLUSION: Tc-99m tetrofosmin scintimammography is an accurate, well tolerated and non-invasive method of differentiating benign from malignant palpable breast lesions. Negative Tc-99m tetrofosmin scintimammography excludes malignancy with a high degree of confidence while false-positive scintigraphy can occur in cases of proliferative dysplasia and hypercellular fibroadenoma. Tc-99m tetrofosmin scintimammography is particularly useful when plain-film mammography is indeterminate or limited in patients with dense breasts or a history of previous surgery and/or radiotherapy.

Adult↗
PubMed1998

Colorectal neoplasm detection using virtual colonoscopy: a feasibility study.

BACKGROUND: Virtual colonoscopy is a potentially powerful tool for non-invasive colorectal evaluation. In vitro studies have established its accuracy in simulated polyp detection but little data exist regarding its use in clinical practice. AIMS: To evaluate the ability of virtual colonoscopy to detect colorectal cancers and polyps in patients with endoscopically proven colorectal neoplasms and to correlate the findings of virtual colonoscopy with those of conventional colonoscopy, surgery, and histopathology. PATIENTS: Thirty eight patients with endoscopic findings suggestive of colorectal carcinoma. METHODS: Virtual colonoscopy was performed using thin section helical computed tomography (CT) of the abdomen and pelvis after rectal insufflation of room air. Commercially available software was used to generate endoscopic "fly through" examinations of the colon from the CT data. Results were correlated with the findings of conventional colonoscopy and with the surgical and histopathological outcome in each case. RESULTS: Thirty eight pathologically proven colorectal cancers and 23 adenomatous polyps were present. On virtual colonoscopy, all cancers and all polyps measuring greater than 6 mm in size were identified; there were two false positive reports of polyps. On conventional colonoscopy, there was one false positive report of a malignant sigmoid stricture; four subcentimetre polyps were overlooked. Virtual colonoscopy enabled visualisation of the entire colon in 35 patients; conventional colonoscopy was incomplete in 14 patients. Virtual colonoscopy correctly localised all 38 cancers, compared with 32 using conventional colonoscopy. CONCLUSION: Virtual colonoscopy is a feasible method for evaluating the colon; it may have role in diagnosis of colorectal cancer and polyps.

Adult↗
PubMed1998

Transrectal US in male infertility: spectrum of findings and role in patient care.

PURPOSE: To determine the findings at transrectal ultrasound (US) in infertile men with low-volume azoospermia and to evaluate its role in patient care. MATERIALS AND METHODS: Transrectal US was performed on 276 infertile men with a mean age of 34 years (range, 24-52 years) who had documented low ejaculate volumes and azoospermia. RESULTS: Of the 276 men, 70 (25.4%) had no anatomic abnormalities. In the remaining patients, abnormalities included congenital bilateral absence of the vas deferens in 94 (34.1%) patients; bilateral occlusion of the vas deferens, seminal vesicles, and ejaculatory ducts by calcification or fibrosis in 43 (15.6%) patients; unilateral absence of the vas deferens in 31 (11.2%) patients; obstructing cysts of the seminal vesicles, vas deferens, ejaculatory ducts, or prostate in 26 (9.4%) patients; and ductal obstruction secondary to calculi in 12 (4.4%) patients. CONCLUSION: Transrectal US is a safe and accurate method for evaluating the distal male reproductive tract that helps identify patients with potentially correctable causes of infertility.

Adult↗
PubMed1998

Unenhanced helical CT criteria to differentiate distal ureteral calculi from pelvic phleboliths.

PURPOSE: To identify imaging features at unenhanced helical computed tomography (CT) that help differentiate distal ureteral calculi from pelvic phleboliths. MATERIALS AND METHODS: Retrospective analysis was performed of 184 pelvic calcifications identified at unenhanced helical CT in 113 patients. The size, shape, and attenuation of each calcification were recorded in addition to the presence of a central lucency and the appearance of the adjacent soft tissues. With profile analysis, a graphic representation was generated of attenuation in each pixel along a line drawn through each calcification. RESULTS: Geometric configuration was seen in eight (21%) calculi but not in any phleboliths. Differences were significant (P < .0001) between the mean attenuation of calculi and that of phleboliths. Among phleboliths, none had a mean attenuation greater than 278 HU, 13 (9%) had a visible central lucency, 31 (21%) had a bifid peak at profile analysis, 30 (21%) had the "comet sign" (adjacent eccentric, tapering soft-tissue mass corresponding to the noncalcified portion of a pelvic vein), and three (2%) had the soft-tissue rim sign (edema of the ureteral wall). Among calculi, none had a central lucency, bifid peak, or comet sign, but 29 (76%) had the soft-tissue rim sign. CONCLUSION: Analysis of pelvic calcifications at unenhanced helical CT can help differentiate calculi from phleboliths.

Calculi↗
PubMed1997

Thin-section helical computed tomography of the bladder: initial clinical experience with virtual reality imaging.

OBJECTIVES: To evaluate the application of virtual reality imaging of the bladder (virtual cystoscopy) in the detection of bladder masses. METHODS: Six patients (mean age 61 years, range 43 to 75) with hematuria and positive findings on conventional cystoscopy were studied by means of thin-section helical computed tomography of the air-distended bladder. Using volume-rendering algorithms, interactive intraluminal views of the bladder mucosa were generated (virtual cystoscopy). Results of virtual cystoscopy were compared with those of conventional cystoscopy in each case. RESULTS: Twenty-six (100%) of 26 masses (mean size 1.7 cm, range 0.3 to 6), detected on conventional cystoscopy, were visualized on virtual cystoscopy. Twelve of 26 masses measured less than 1 cm in maximum diameter. All masses were pathologically proven transitional cell carcinomas. Virtual cystoscopy was well tolerated by all patients, and no complications occurred. CONCLUSIONS: Our results indicate that virtual cystoscopy is an accurate technique for detection of intrinsic bladder masses. It may represent a radiologic adjunct to conventional cystoscopy for initial evaluation of patients with hematuria and for surveillance of patients after bladder tumor resection.

Adult↗
PubMed1997

Lung findings on high-resolution computed tomography in idiopathic ankylosing spondylitis--correlation with clinical findings, pulmonary function testing and plain radiography.

Previous studies on the association of ankylosing spondylitis and abnormalities of the lung parenchyma have been based largely on plain radiography and pulmonary function testing. This study, although uncontrolled, is the first to use high-resolution computed tomography to examine the entire lung parenchyma in ankylosing spondylitis patients, and to correlate the findings with clinical assessment, plain radiography and pulmonary function testing. The study population comprised 26 patients meeting the New York criteria for idiopathic ankylosing spondylitis who attended the out-patient department at our institution. High-resolution computed tomography examination revealed abnormalities in 19 patients (70%): these included interstitial lung disease (n = 4), bronchiectasis (n = 6), emphysema (n = 4), apical fibrosis (n = 2), mycetoma (n = 1) and non-specific interstitial lung disease (n = 12). Plain radiography was abnormal in only four patients and failed to identify any patient with interstitial lung disease. All patients with interstitial lung disease on high-resolution computed tomography had respiratory symptoms and three of the four had evidence of a restrictive process on pulmonary function testing. This study raises, for the first time, the possible association between interstitial lung disease and ankylosing spondylitis, and highlights the use of high-resolution computed tomography in detecting such disease in ankylosing spondylitis patients.

Adult↗
PubMed1997

Benign versus malignant breast disease: comparison of contrast-enhanced MR imaging and Tc-99m tetrofosmin scintimammography.

PURPOSE: To compare technetium-99m tetrofosmin scintimammography with contrast material-enhanced magnetic resonance (MR) imaging in the characterization of palpable breast masses. MATERIALS AND METHODS: Forty-seven patients (mean age, 51 years) with a palpable breast mass were prospectively examined with scintimammography, MR imaging, and conventional mammography 2 weeks before fine-needle aspiration biopsy. RESULTS: In three patients, MR imaging was aborted. Of the remaining 44 patients, 21 had biopsy-proved cancer and 23 had benign disease. The sensitivity of mammography was 81%; specificity, 82%; positive predictive value (PPV), 85%; and negative predictive value (NPV), 78%. The sensitivity of scintimammography was 95%; specificity, 91%; PPV, 91%; and NPV, 95%. The sensitivity of MR imaging was 90%; specificity, 91%; PPV, 90%; and NPV, 91%. In 11 patients with previous breast cancer, scintimammographic findings were positive in all four with tumor recurrence and negative in all seven with benign disease. Masses were correctly characterized with MR imaging in eight of these 11 patients. CONCLUSION: Although both techniques accurately differentiate benign from malignant palpable breast masses, scintimammography is more accurate in the posttreatment breast. Because of lower cost, wider availability, and high patient acceptance, scintimammography may provide a valuable alternative to MR imaging for noninvasive characterization of palpable breast disease.

Adult↗
PubMed1997

Virtual cystoscopy: early clinical experience.

Virtual cystoscopy was performed in 13 patients with hematuria and abnormal findings at conventional cystoscopy. Perspective volume-rendering algorithms were applied to helical computed tomographic data to generate interactive, intraluminal views of the bladder mucosa after insufflation of room air. At conventional cystoscopy, 29 masses appeared to arise from the bladder mucosa and two were hypertrophied median lobes of the prostate. At virtual cystoscopy, 30 masses arose from the bladder (one prostate mass was misinterpreted as an intrinsic bladder mass). Results at virtual cystoscopy were comparable to those at conventional cystoscopy but were obtained without the associated risks.

Aged↗
PubMed1997

Plain radiographs and thoracic high-resolution CT in patients with ankylosing spondylitis.

OBJECTIVE: The aims of this study were to identify the spectrum of abnormalities seen on high-resolution CT in patients with ankylosing spondylitis and to compare our findings with reports of plain film pulmonary manifestations of the disease. SUBJECTS AND METHODS: We prospectively studied 26 patients with documented ankylosing spondylitis. All patients underwent plain chest radiography (posteroanterior and lateral views), thoracic helical CT, high-resolution CT, and pulmonary function tests. RESULTS: High-resolution CT revealed abnormalities in 18 patients (69%), whereas plain chest radiography revealed abnormalities in four patients (15%). The most common abnormalities seen on CT were interstitial lung disease (ILD) (n = 4), bronchial wall thickening and bronchiectasis (n = 6), paraseptal emphysema (n = 3), mediastinal lymphadenopathy (n = 3), tracheal dilatation (n = 2), and apical fibrosis (n = 2). CONCLUSION: This study, which describes high-resolution CT findings in patients with ankylosing spondylitis, reveals a spectrum of abnormalities unlike those described in previous reports in which researchers used plain chest radiographs as the sole imaging technique. In addition to apical fibrosis, high-resolution CT revealed nonapical ILD, bronchiectasis, paraseptal emphysema, and tracheobronchomegaly. Of these new findings, we believe that identification of ILD is the most important. We suggest that nonapical ILD should be actively sought as an explanation for pulmonary symptoms developing in patients with ankylosing spondylitis. High-resolution CT should form an integral part of such workup.

Adult↗
PubMed1997

CT colonoscopy of colorectal neoplasms: two-dimensional and three-dimensional virtual-reality techniques with colonoscopic correlation.

OBJECTIVE: The aim of this study was to compare the diagnostic accuracy of two-dimensional (2D) CT colonography and three-dimensional (3D) virtual colonoscopy with conventional colonoscopy in patients who have suspected colorectal neoplasms. SUBJECTS AND METHODS: Twenty patients were studied (eight women and 12 men; mean age, 53 years; range, 42-85 years). All patients had findings on conventional colonoscopy suggestive of colorectal carcinoma and underwent colonic CT within 3 hr of endoscopy. Two-dimensional CT colonography and 3D virtual colonoscopy images were generated from the same data set that was obtained from thin-section helical CT of the abdomen and pelvis after rectal insufflation of room air. Three-dimensional virtual colonoscopy images were obtained by downloading CT data to a workstation equipped with commercially available software. Volume- and perspective-rendering techniques were used to achieve interactive, 3D virtual "fly-through" examinations of the colonic mucosa. The results of 2D CT colonography and 3D virtual colonoscopy were compared with the findings of conventional colonoscopy and correlated with surgical and pathologic outcome where possible. RESULTS: Twenty masses (defined as intraluminal projections 2 cm or larger in diameter) and 15 polyps (defined as projections smaller than 2 cm in diameter) were identified in our study group. All masses and 14 of 15 polyps were successfully shown on 2D colonography. Three findings of polyps on 2D colonography were false-positive, and one was false-negative. Three-dimensional virtual colonoscopy revealed 19 of 20 masses and 13 of 15 polyps. On conventional colonoscopy, all 20 masses and 13 of 15 polyps were identified, with one false-positive finding of a malignant stricture in a normal colon. Complete examination of the colon was possible in 18 of 20 patients using the 2D technique and in 17 of 20 patients using 3D virtual colonoscopy, whereas conventional colonoscopy showed the entire colon in only 12 of 20 patients. CONCLUSION: Two-dimensional CT colonography and 3D virtual colonoscopy are complementary and effective techniques for examining the colon in patients with suspected colorectal carcinoma. CT techniques offer several advantages over conventional colonoscopy including the ability to detect abnormalities proximal to obstructing carcinomas, accurate localization of abnormalities within the colon, and good patient tolerance. These CT techniques may play an important role in future diagnosis of colorectal cancer and for screening patients at risk.

Colonic Polyps↗