Biomedical subjects

M M McNicholas

Publications and source records attributed to M M McNicholas.

27 records · Page 2Linked to original sources

PubMed1994

Sonography in optic disk drusen: imaging findings and role in diagnosis when funduscopic findings are normal.

OBJECTIVE: Optic disk drusen are relatively benign lesions of the eye but can cause visual symptoms and may occasionally mimic papilledema on funduscopy. We studied the range of sonographic findings and determined if sonography can be used to diagnose this condition in the absence of typical funduscopic findings. SUBJECTS AND METHODS: Sonography of the eyes was performed in 12 patients with known or suspected optic disk drusen by using a 10-MHz transducer. Optic disk drusen were diagnosed clinically in 16 of the 24 eyes. The funduscopic appearance was typical in 11 eyes and atypical in five eyes. In these five patients, the diagnosis was made on the basis of an abnormal appearance of the disk and either a strong family history of drusen (four patients) or funduscopic findings that were typical of drusen in the opposite eye (one patient). RESULTS: The head of the optic nerve was abnormal in 19 of 24 eyes on sonography and in 16 on funduscopy. In all cases with abnormal findings on sonograms, an ovoid echogenic lesion was evident at the junction of the retina and the optic nerve. The lesions varied in size from 1.5 to 4.0 mm in diameter and from 1 to 3 mm in thickness and projected posteriorly rather than into the vitreous body. Calcification was evident on sonograms in 16 cases. The degree of acoustic shadowing was proportional to the size of the echogenic focus. In the three cases in which funduscopic findings were normal, sonography showed small drusen deposits. In the five eyes that showed disk abnormality but were not typical of drusen on funduscopy, sonography showed lesions of varying size; cases with typical funduscopic appearances tended to show large lesions on sonography. CONCLUSION: Optic disk drusen can be diagnosed on the basis of their typical sonographic appearance even in the absence of typical funduscopic findings. Optic disk drusen may be seen incidentally when sonograms are made for other conditions, and the finding should not be confused with more serious lesions of the optic nerve.

Adolescent↗

PubMed1994

Pain and increased mammographic density in women receiving hormone replacement therapy: a prospective study.

OBJECTIVE: A prospective study was designed to evaluate the effects of hormone replacement therapy on mammographic density in postmenopausal women. The possible association of breast pain with increased mammographic density was evaluated. SUBJECTS AND METHODS: Thirty-three postmenopausal women undergoing hormone replacement therapy for a mean of 11 months had mammography before and after commencing treatment. As a control, 31 postmenopausal women who never had hormone therapy also had baseline and follow-up mammograms after a mean of 13 months. Subjects were asked whether breast pain, which they graded as mild, moderate, or severe, had developed since their entry into the study. Baseline and follow-up mammograms were assessed objectively and subjectively for interval changes in density. The presence of breast pain was correlated with changes in density on the mammograms. RESULTS: A subjective increase in mammographic density was seen in nine (27%) of the women taking hormones and in none of the control subjects (p = .002). Changes were focal in four, multifocal in four, and diffuse in one. An increase in density was seen with all types of treatment used, and was noted as early as 4 months after the start of treatment. Seven (78%) of nine patients with mammographic changes had breast pain, which they classed as moderate or severe, that had developed since the start of treatment. In five patients with mild or moderate breast pain, an increase in density was not shown on mammograms. Of the 21 women taking hormones who did not have breast pain, increased density on follow-up mammograms was shown in only two (p = .004). None of the patients in the control group had breast pain. CONCLUSION: Focal, multifocal, or diffuse mammographic increases in density occur in a significant percentage of women undergoing hormone replacement therapy. A large proportion of these women have breast pain. Increased mammographic density appears to be associated with breast pain in women receiving hormones. This has implications for mammography in women receiving hormone replacement therapy.

Breast↗

PubMed1994

Ocular sonography.

High-frequency ocular sonography is the ideal method for imaging the eye and intraocular structures. In the presence of opaque ocular media, a complete view of the fundus may be impossible ophthalmoscopically, and in these cases sonography is invaluable. Although high field strength MR imaging with surface coils provides excellent detail of normal and pathologic ocular structures, major shortcomings are lack of spatial resolution and poor specificity with certain lesions. Sonography is superior to CT or MR imaging in detecting ocular lesions such as small melanomas that are 2 mm or less in thickness. The eye can be examined dynamically during eye movements, which is of value in localizing abnormalities. The sonographic appearance of a variety of ocular pathologic conditions is illustrated in this essay.

Eye↗

PubMed1993

Color Doppler sonography in the evaluation of palpable breast masses.

OBJECTIVE: A prospective study was performed to determine the value of high-resolution color Doppler sonography in the evaluation of palpable solid breast masses. SUBJECTS AND METHODS: One hundred thirty-one consecutive breast lesions were characterized as benign, malignant, or indeterminate on the basis of their sonographic appearance. The number of blood vessels was estimated, the Doppler spectrum for each vessel was characterized, and the maximum velocity was recorded. Mammography was performed in most cases. Histology was obtained in all cases. RESULTS: Predictions based on sonography alone were correct in 74% of benign lesions and 63% of malignant lesions (p < .001). Blood flow was demonstrated in 87% of malignant lesions and in 68% of benign lesions (p = .0105). Malignant lesions were larger than benign lesions (p = .004) and showed a significantly greater number of vessels (p < .001) and significantly higher maximum velocity (mean, 34.2 vs 19.2 cm/sec; p < .001). Patients with malignant lesions were significantly older (p < .001). When age, size of lesion, and sonographic morphology were controlled, the presence of blood flow did not aid in diagnosis. However, in lesions with blood flow, when spectral patterns and maximum velocity were analyzed, a logistic model combining these parameters with age, size, and sonographic morphology gave an overall sensitivity of 94%, specificity of 93%, and positive predictive value of 92%. Mammography yielded useful additional information, particularly for indeterminate lesions. CONCLUSION: Maximum velocity and spectral patterns on Doppler analysis are useful indicators of breast malignancy, but only if the patient's age, the size of the lesion, and the sonographic morphology are also considered. The best use of color flow imaging is in combination with mammography.

Adolescent↗

PubMed1992

Morphological appearance of renal allografts in transplant failure.

Renal allograft dysfunction may be due to a variety of causes including acute and chronic rejection, acute tubular necrosis, cyclosporine A toxicity, glomerulonephritis, and surgical causes. It can be difficult to distinguish between these etiologies. Ultrasound is a relatively simple, noninvasive method for imaging the transplant kidney, and is excellent for the diagnosis of surgical complications. The features of rejection include an increase in renal volume, reduced echogenicity, indistinctness of the corticomedullary junction, and splaying of the medullary pyramids. These findings, although suggestive of rejection, cannot differentiate reliably between rejection and other causes of allograft hypofunction. Doppler studies may show an increased resistive index in a kidney undergoing rejection, but this finding may also be seen in other pathological processes and is not specific. A normal ultrasound examination does not exclude rejection. Ultrasound is useful as a baseline examination. Abnormal findings should be interpreted in the light of the clinical situation in each case. Where there is any doubt about the diagnosis, ultrasound-guided biopsy should be performed.

Graft Rejection↗

PubMed1991

Idiopathic inflammatory pseudotumour of the orbit: CT features correlated with clinical outcome.

Idiopathic orbital pseudotumour is an inflammatory condition which usually presents as an orbital mass. The response to treatment is variable and often unpredictable. In this study we have assessed the spectrum of computed tomographic (CT) appearances in 17 patients. Four categories of orbital pseudotumour were identified by CT based on the location and extent of the inflammatory process within the orbit. Patients within each of the four categories had broadly similar clinical outcomes. CT was valuable in identifying certain prognostic features enabling better clinical and therapeutic planning.

Adolescent↗

PubMed1991

Ultrasound of the pelvis and renal tract combined with a plain film of abdomen in young women with urinary tract infection: can it replace intravenous urography? A prospective study.

Urinary tract infection (UTI) is common in women and intravenous urography (IVU) is a frequently requested radiological investigation for recurrent UTI. The aim of this study was to assess whether pelvic and renal ultrasound combined with a plain film of the abdomen (KUB) could replace IVU as the initial radiological investigation in young women with recurrent UTI. Ninety-four young women with recurrent UTI who were referred for IVU were studied. Ultrasound of the pelvis and renal tract was performed, and information obtained from ultrasound and KUB was compared with that obtained from the IVU examination. Patient management was altered as a result of radiological investigation in eight cases. A case of staghorn calculus and a case of pelviureteric junction obstruction were diagnosed by both IVU and ultrasound with KUB. An intrarenal abscess was diagnosed by ultrasound in a patient with a normal IVU. In addition ultrasound demonstrated significant findings in the pelvis, including ovarian and uterine abnormalities and an ectopic and an intrauterine pregnancy. In all cases the patient had symptoms referable to the urinary tract and a history of documented UTI. The KUB did not yield any unsuspected finding not diagnosed by ultrasound, but did serve to delineate more clearly the extent of calculus disease in two patients. We suggest that ultrasound of the pelvis and renal tract combined with a KUB should be the radiological investigation of choice in young women with UTI.

Adolescent↗

PubMedDate not supplied

Radiologically guided balloon dilatation of obstructing gastrointestinal strictures.

Balloon dilatations is the preferred method of dilatation for most gastrointestinal strictures, because of its efficacy and relative safety. Radiologically guided balloon dilatation was successful in 20 of 24 patients referred for dilatation with a variety of tight gastrointestinal strictures with diameters of 0.5 cm or less. Attempts at endoscopic or bougie dilatation had either failed or were felt unlikely to be successful. A satisfactory result was obtained in all cases in which dilatation was performed. There were no serious complications. Radiologically guided balloon dilatation is both safe and effective for the treatment of very tight or obstructing gastrointestinal strictures.

Adult↗

PubMedDate not supplied

Delayed presentation of traumatic splenic arterio-venous fistula.

We report a patient who presented with dyspnoea and was found on examination to have a machinery murmur in the left upper quadrant of the abdomen. The patient had sustained blunt abdominal trauma one year prior to presentation. A diagnosis of splenic arteriovenous fistula was made. The diagnosis and management of delayed presentation of traumatic splenic arteriovenous fistula are discussed.

Abdominal Injuries↗