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Biomedical subjects

Steve Halligan

Publications and source records attributed to Steve Halligan.

51 records · Page 3Linked to original sources
PubMed2003

Efficacy of fibrin sealant in the management of complex anal fistula: a prospective trial.

PURPOSE: A prospective trial was conducted to establish long-term healing of complex idiopathic anorectal fistula, without extension, after fibrin glue treatment, with clinical assessment and magnetic resonance imaging to determine tract healing. METHODS: Twenty-two patients undergoing glue instillation after fistula curettage and irrigation were followed up for a median of 14 months. Clinical assessment, short tau inversion recovery sequence magnetic resonance imaging, and combined short tau inversion recovery and dynamic contrast-enhanced magnetic resonance imaging were performed at a median of three months postoperatively, and their ability to predict outcome in the presence of early skin healing was determined. RESULTS: Of 22 patients, 19 (86.5 percent) had transsphincteric fistulas, 1 (4.5 percent) had a suprasphincteric fistula, 1 (4.5 percent) had an extrasphincteric fistula, and 1 (4.5 percent) had a rectovaginal fistula. None had clinical or radiologic evidence of secondary extension. Despite skin healing in 17 (77 percent) of 22 patients at a median of 14 days after treatment, only 3 (14 percent) remained healed at 16 months. Magnetic resonance imaging with short tau inversion recovery sequences in combination with dynamic contrast-enhanced magnetic resonance imaging predicted outcome in all 10 assessments (100 percent), compared with short tau inversion recovery sequence alone in 16 (94 percent) of 17 assessments or clinical examination in 12 (71 percent) of 17 (P = 0.02). CONCLUSIONS: The success rate of fibrin glue application for complex anorectal fistulas without extension is 14 percent. Magnetic resonance imaging predicts outcome at an earlier stage than clinical examination.

Adult↗
PubMed2003

MR imaging of fistula-in-ano.

Accurate preoperative assessment of fistula-in-ano is mandatory if the fistula is not to recur. In recent years, MRI has become pre-eminent for fistula assessment and recent studies have shown that not only is MRI more accurate than surgical assessment, but that surgery based on MRI can reduce further disease recurrence by approximately 75%. The main role of MRI is to alert the surgeon to fistula tracks and extensions that would otherwise have gone undetected and, thus, untreated at the time of surgical assessment under general anaesthetic.

Anal Canal↗
PubMed2003

Multi-detector row CT colonography: effect of collimation, pitch, and orientation on polyp detection in a human colectomy specimen.

PURPOSE: To investigate the effects of orientation, collimation, pitch, and tube current setting on polyp detection at multi-detector row computed tomographic (CT) colonography and to determine the optimal combination of scanning parameters for screening. MATERIALS AND METHODS: A colectomy specimen containing 117 polyps of different sizes was insufflated and imaged with a multi-detector row CT scanner at various collimation (1.25 and 2.5 mm), pitch (3 and 6), and tube current (50, 100, and 150 mA) settings. Two-dimensional multiplanar reformatted images and three-dimensional endoluminal surface renderings from the 12 resultant data sets were examined by one observer for the presence and conspicuity of polyps. The results were analyzed with Poisson regression and logistic regression to determine the effects of scanning parameters and of specimen orientation on polyp detection. RESULTS: The percentage of polyps that were detected significantly increased when collimation (P =.008) and table feed (P =.03) were decreased. Increased tube current resulted in improved detection only of polyps with a diameter of less than 5 mm. Polyps of less than 5 mm were optimally depicted with a collimation of 1.25 mm, a pitch of 3, and a tube current setting of 150 mA; polyps with a diameter greater than 5 mm were adequately depicted with 1.25-mm collimation and with either pitch setting and any of the three tube current settings. Small polyps in the transverse segment (positioned at a 90 degrees angle to the z axis of scanning) were significantly less visible than those in parallel or oblique orientations (P <.001). The effective radiation dose, calculated with a Monte Carlo simulation, was 1.4-10.0 mSv. CONCLUSION: Detection of small polyps (<5 mm) with multi-detector row CT is highly dependent on collimation, pitch, and, to a lesser extent, tube current. Collimation of 1.25 mm, combined with pitch of 6 and tube current of 50 mA, provides for reliable detection of polyps 5 mm or larger while limiting the effective radiation dose. Polyps smaller than 5 mm, however, may be poorly depicted with use of these settings in the transverse colon.

Colon↗
PubMed2003

Cardiovascular effects at multi-detector row CT colonography compared with those at conventional endoscopy of the colon.

PURPOSE: To compare the cardiovascular effects of computed tomographic (CT) colonography and conventional endoscopy in a group of patients undergoing both procedures. MATERIALS AND METHODS: A total of 144 patients underwent CT colonography followed by flexible sigmoidoscopy (40 patients) or colonoscopy (104 patients). Pulse, blood pressure, and oxygen saturation were measured before, during, and after the procedures. Forty patients also underwent continuous Holter electrocardiographic (ECG) monitoring. Periprocedural pain was assessed by using a handheld counting device. Outcome variables were assessed by using a combination of paired t testing and multilevel linear regression. RESULTS: When a spasmolytic was not used, CT colonography was associated with only a small increase in oxygen saturation (P =.03), while use of a spasmolytic caused an increase in pulse (mean increase, 19.9 beats per minute; P <.001) and diastolic blood pressure (mean increase, 5 mm Hg; P <.001). Compared with that at CT, oxygen saturation decreased significantly during and after colonoscopy and sigmoidoscopy (mean decrease after colonoscopy with sedation, 1.0%; P <.001). Systolic and diastolic blood pressure also decreased during and after colonoscopy (mean systolic decrease after colonoscopy with sedation, 16.6 mm Hg, P <.001; mean diastolic decrease after colonoscopy with sedation, 7.5 mm Hg, P <.001). Patients were 30.3 times more likely to develop bradycardia after endoscopy (95% CI: 2.65, 346; P =.006). Ventricular couplets were significantly higher at endoscopy than at CT in patients with a history of cardiac disease (odds ratio: 72.5 and 95% CI: 4.56, 1,153 at CT vs odds ratio: 14.6 and 95% CI: 0.96, 222 at endoscopy; P =.002). Patients were 1.89 times more likely to register pain during colonoscopy than during CT (95% CI: 1.06, 3.38; P =.03). CONCLUSION: CT colonography had no significant cardiovascular effect other than spasmolytic-induced tachycardia. Endoscopy-and colonoscopy in particular-causes cardiovascular effects that are largely related to sedation. CT colonography is less painful than colonoscopy and is comparable to flexible sigmoidoscopy.

Adult↗
PubMed2003

Acceptance by patients of multidetector CT colonography compared with barium enema examinations, flexible sigmoidoscopy, and colonoscopy.

OBJECTIVE: The purpose of this study was to compare patient acceptance of multidetector CT colonography, total colonoscopy, flexible sigmoidoscopy, and double-contrast barium enema to ascertain any overall preference. SUBJECTS AND METHODS. One hundred sixty-eight patients underwent CT colonography followed by either flexible sigmoidoscopy (n = 59) or colonoscopy (n = 109). A 25-point questionnaire with principal components relating to satisfaction, worry, and physical discomfort was administered after CT colonography and after endoscopy, and a follow-up questionnaire was administered 1 week after the procedures. Questionnaires were also completed by 140 patients undergoing double-contrast barium enema examinations. Responses were compared using Wilcoxon's matched pairs test and the Mann-Whitney test. RESULTS: Overall satisfaction was greater with colonoscopy (p = 0.01), but CT colonography caused less discomfort (p = 0.002), was better tolerated (p = 0.005), and was the preferred follow-up investigation of those expressing a preference (p = 0.003). Compared with flexible sigmoidoscopy, CT colonography caused less pain (p = 0.004), was more acceptable (p = 0.04), and was preferred as the follow-up investigation (p < 0.001). Tolerance of colonoscopy was significantly less in women (p = 0.03), but such was not the case for CT colonography (p = 0.58). Patients undergoing CT colonography were less worried (p < 0.001), were more satisfied (p = 0.001), and suffered less discomfort (p < 0.001) than those having barium enema. CONCLUSION: Patients' experiences with barium enema examinations were significantly worse than with any other test. Although patients were most satisfied with colonoscopy, they reported more pain during both colonoscopy and sigmoidoscopy than during CT colonography, and they also found CT more acceptable. In patients expressing a preference, CT colonography was the preferred follow-up investigation.

Adult↗
PubMed2002

Effect of MRI on clinical outcome of recurrent fistula-in-ano.

Recurrent fistula-in-ano is usually due to sepsis missed at surgery, which can be identified by MRI. We aimed to establish the therapeutic effect of MRI in patients with fistula-in-ano. We did MRI in 71 patients with recurrent fistula, with further surgery done at the discretion of the surgeon. Surgery and MRI agreed in 40 patients, five (13%) of whom had further recurrence, compared with 16 (52%) of 31 in whom surgery and MRI disagreed (p=0.0005). Further recurrence in all 16 was at the site predicted by MRI. For surgeons who always acted on MRI, further recurrences arose in four of 25 (16%) operations versus eight of 14 (57%) operations for those who ignored imaging (p=0.008). Surgery guided by MRI reduces further recurrence of fistula-in-ano by 75% and should be done in all patients with recurrent fistula.

Adolescent↗
PubMed2002

Dynamic magnetic resonance imaging evaluation of the structural and functional results of postanal repair for neuropathic fecal incontinence.

PURPOSE: The aim of this study was to determine whether dynamic magnetic resonance imaging of the pelvic floor can discriminate between patients who improve after postanal repair for neurogenic fecal incontinence and those who remain symptomatic. METHODS: Pelvic floor measurements obtained during dynamic magnetic resonance imaging in eight females whose anal incontinence had improved after postanal repair were compared with those from nine females who remained symptomatic. All subjects also underwent standard anorectal physiology testing. RESULTS: There was no significant difference between groups with respect to any measurement of anterior or middle pelvic floor compartments. Additionally, there was no difference in posterior pelvic floor configuration when symptomatic patients were compared with those who had improved. However, dynamic magnetic resonance measurements revealed patients who remained symptomatic had significantly greater posterior pelvic floor weakness. Anorectal physiology was unable to differentiate between groups. CONCLUSIONS: There is no difference in static pelvic floor measurements when subjects remaining symptomatic after postanal repair are compared with those who have improved. In contrast, dynamic measurements may be able to predict failure in those who demonstrate excessive posterior pelvic floor mobility.

Adult↗
PubMed2002

Influence of the subpubic arch angle on anal sphincter trauma and anal incontinence following childbirth.

OBJECTIVE: To assess the relationship between the subpubic arch angle, anal sphincter and perineal trauma, and anal incontinence after childbirth in nulliparous women. DESIGN: Prospective cohort study. SETTING: University teaching hospital. SAMPLE: One hundred thirty-four low risk nulliparous women. METHODS: Measurements of the bony pelvic outlet were made to calculate the subpubic arch angle. Endosonographic assessment of the perineum and anal sphincter was made before and after delivery. A specific bowel function questionnaire was completed before and after delivery. MAIN OUTCOME MEASURES: Perineal and anal sphincter trauma, and deteriorating anal continence after delivery. RESULTS: Thirty-two women with a subpubic arch angle of less than 90 degrees had significantly prolonged first and second stages of labour when compared with 102 women whose subpubic arch was wider. Following delivery, anal continence deteriorated in more women with a narrow subpubic angle (69% vs 21%, P < 0.001) but this was unrelated to the incidence of anal sphincter and perineal trauma. CONCLUSIONS: A narrow subpubic arch is strongly associated with prolonged labour and postpartum anal incontinence in nulliparous women. However, perineal and anal sphincter trauma, assessed by ultrasound, does not account for the higher rate of postpartum analincontinence in women with a narrow subpubic arch angle.

Adult↗
PubMed2002

Imaging diverticular disease.

Barium enema remains the gold standard for demonstrating the extent and severity of colonic diverticular disease. As such, barium studies have a role in clarifying the differential diagnosis of patients with abdominal pain and altered gut function. In acute diverticulitis or suspected diverticular perforation water soluble contrast studies are preferred to barium. An alternative in this acute scenario is cross-sectional imaging by ultrasound, or more usefully computed tomography (CT). CT is especially helpful in complicated diverticular disease. Diverticular disease is a common finding at colonoscopy and is often a complicating factor in the technical performance of the procedure. In acute diverticulitis, when the risk of perforation is high, colonoscopy should not be performed. In acute diverticular haemorrhage, colonoscopic haemostatic therapy with adrenaline can be effectively performed.

Barium Sulfate↗
PubMed2002

Female anal sphincter: age-related differences in asymptomatic volunteers with high-frequency endoanal US.

PURPOSE: To evaluate endoanal ultrasonographic (US) anatomy in a large group of nulliparous women by using a high-frequency 10-MHz transducer to define normal age-related differences in sphincter morphology. MATERIALS AND METHODS: One hundred fifty asymptomatic nulliparous women (mean age, 31 years; range, 19-80 years) underwent endoanal US with a high-frequency 10-MHz transducer. Anal canal structures were measured at high, middle, and low levels and were correlated with age by using the Pearson simple linear correlation coefficient. RESULTS: Internal sphincter thickness showed a highly significant positive correlation with age at both sites at which it was measured (high anal canal, r = 0.34, P <.001; middle anal canal, r = 0.33, P <.001). External sphincter thickness showed a highly significant negative correlation with age at all sites measured (high anal canal, r = -0.65, P <.001; middle anal canal, r = -0.49, P <.001; low anal canal, r = -0.21, P =.012). There was no significant correlation between age and thickness of subepithelial tissue, longitudinal muscle, or puborectalis muscle. Subjects whose internal sphincter showed mixed echogenicity were significantly older than those whose internal sphincter was uniformly hypoechoic (mean, 47.4 vs 34.6 years; P <.001). Subjects with mixed internal sphincter echogenicity also had a significantly thinner external sphincter at high (mean thickness, 3.8 vs 4.6 mm; P <.001) and middle (mean thickness, 3.7 vs 4.1 mm; P =.03) anal canal levels. CONCLUSION: At older ages there are increased internal anal sphincter thickness and decreased external anal sphincter thickness. Diagnosis of external sphincter atrophy on the basis of sphincter thinning requires that one distinguish between abnormal thinning and age-related differences.

Adult↗
PubMed2001

Imaging of the posterior pelvic floor.

Disorders of the posterior pelvic floor are relatively common. The role of imaging in this field is increasing, especially in constipation, prolapse and anal incontinence, and currently imaging is an integral part of the investigation of these pelvic floor disorders. Evacuation proctography provides both structural and functional information for rectal voiding and prolapse. Dynamic MRI may be a valuable alternative as the pelvic floor muscles are visualised, and it is currently under evaluation. Endoluminal imaging is important in the management of anal incontinence. Both endosonography and endoanal MRI can be used for detection of anal sphincter defects. Endoanal MRI has the advantage of simultaneously evaluating external sphincter atrophy, which is an important predictive factor for the outcome of sphincter repair. Many aspects of constipation and prolapse remain incompletely understood and treatment is partly empirical; however, imaging has a central role in management to place patients into treatment-defined groups.

Constipation↗
PubMedDate not supplied

Staging rectal cancer: MRI compared to MDCT.

PURPOSE: To audit the accuracy with which pre-operative MRI and multi-detector row CT determine the relationship between rectal tumour and the circumferential resection margin (CRM). MATERIALS AND METHODS: The MR and CT scans of 72 patients with rectal adenocarcinoma were retrieved. The relationship between tumour and the mesorectal fascia was determined by two observers, who classified appearances into three categories: no tumour within 5 mm of the mesorectal fascia; tumour within 5 mm of the mesorectal fascia ('threatened' margin); tumour at the mesorectal fascia ('involved' margin). Agreement with post-operative histopathology was assessed by Kappa statistics. RESULTS: There was poor agreement between both MRI and CT, and post-operative histology, both in all 72 patients and in the 42 who had received no pre-operative therapy or short-course radiotherapy only. Both imaging modalities had a tendency to overstage patients whose CRM was uninvolved subsequently. However, the negative predictive value for an uninvolved margin was 81.8% by MRI and 84.6% by CT. There was no patient with an involved margin by histopathology whose imaging had suggested the margin was uninvolved. CONCLUSION: Both pre-operative MRI and multi-detector row CT have high negative predictive values for a subsequently uninvolved resection margin.

Adenocarcinoma↗
PubMedDate not supplied

Quantitative colorectal cancer perfusion measurement using dynamic contrast-enhanced multidetector-row computed tomography: effect of acquisition time and implications for protocols.

OBJECTIVE: To determine the effect of acquisition time on quantitative colorectal cancer perfusion measurement. METHODS: Dynamic contrast-enhanced computed tomography (CT) was performed prospectively in 10 patients with histologically proven colorectal cancer using 4-detector row CT (Lightspeed Plus; GE Healthcare Technologies, Waukesha, WI). Tumor blood flow, blood volume, mean transit time, and permeability were assessed for 3 acquisition times (45, 65, and 130 seconds). Mean values for all 4 perfusion parameters for each acquisition time were compared using the paired t test. RESULTS: Significant differences in permeability values were noted between acquisitions of 45 seconds and 65 and 130 seconds, respectively (P=0.02, P=0.007). There was no significant difference for values of blood volume, blood flow, and mean transit time between any of the acquisition times. CONCLUSIONS: Scan acquisitions of 45 seconds are too short for reliable permeability measurement in the abdomen. Longer acquisition times are required.

Adenocarcinoma↗
PubMedDate not supplied

Computed tomography colonography: automated diameter and volume measurement of colonic polyps compared with a manual technique--in vitro study.

OBJECTIVE: To investigate inter- and intraobserver agreement of automated measurement of polyp diameter in vitro. METHODS: Two phantoms ("QRM" and "Whiting") containing simulated polyps of known diameter and volume were scanned using 16-detector row computed tomography. Two observers estimated polyp diameter using 3 methods: software calipers ("manual"), freehand boundary identification ("semiautomatic"), and automated software segmentation ("fully automatic"). RESULTS: Intraobserver 95% limits of agreement for diameter were narrowest for the fully automatic method (QRM span: 0.39 mm, 0.48 mm; Whiting span: 0.24 mm, 0 mm). Manual estimates were approximately 10 times wider (QRM span: 3.57 mm, 3.21 mm; Whiting span: 3.2 mm, 2.02 mm). Volume estimates were narrowest for the fully automatic method (span: 24.2 mm, 24.1 mm vs. 97.9 mm, 102.9 mm for semiautomatic measurement). Interobserver agreement for diameter was narrowest for the fully automatic method (QRM span: 0.12 mm, Whiting span: 0.16 mm), with the manual method approximately 18 times wider (QRM span: 2.87 mm, Whiting span: 2.18 mm). CONCLUSION: Fully automated measurement of polyp diameter and volume is technically feasible and results in superior inter- and intraobserver agreement.

Colonic Polyps↗