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Biomedical subjects

J Stoker

Publications and source records attributed to J Stoker.

At least 73 records · Page 4Linked to original sources
PubMed1999

Fecal incontinence: endoanal US versus endoanal MR imaging.

PURPOSE: To assess endoanal ultrasonography (US) and endoanal magnetic resonance (MR) imaging for mapping of anal sphincter defects that have been validated at surgery in patients with fecal incontinence. MATERIALS AND METHODS: US, MR imaging, and surgical findings in 22 women with fecal incontinence who underwent sphincter repair were retrospectively reviewed. US and MR imaging had been performed before surgery. The findings were evaluated separately and validated with surgical results. RESULTS: Endoanal MR imaging findings showed better agreement with surgical results than did endoanal US findings for diagnosis of lesions of the external sphincter (kappa value, 0.85 vs 0.53) and of the internal sphincter (kappa value, 0.64 vs 0.49). Endoanal US could not accurately demonstrate thinning of the external sphincter. MR imaging results correlated moderately with US results (kappa = 0.39). If endoanal MR images alone had been considered, the correct surgical decision would have been made in 21 (95%) patients; if endoanal US images alone had been considered, the correct decision would have been made in 17 (77%) patients. CONCLUSION: MR imaging is more accurate than US for demonstration of sphincter lesions. MR imaging provides higher spatial resolution and better inherent image contrast for lesion characterization. Endoanal MR imaging allows more precise description of the extent and structure of complex lesions and is superior for help in decisions about optimal therapy.

Anal Canal↗
PubMed1998

[Unconventional imaging techniques in inflammatory bowel diseases].

In patients with inflammatory bowel disease (IBD), radiologic examinations are important for diagnosis and treatment. With conventional X-ray examinations, mucosal abnormalities, ulcers and fistulas can be visualised, but no information on the extramural extension of the disease can be obtained. Newer radiologic modalities (ultrasound, CT and MRI) offer new diagnostic possibilities. With ultrasound IBD can be diagnosed with good confidence and it can differentiate between Crohn's disease and ulcerative colitis. CT and MRI are indicated not so much to diagnose the disease but rather to determine the severity and spread of disease activity (transmural and extramural inflammation) and to detect complications such as fistulas and abscesses.

Colitis, Ulcerative↗
PubMed1998

Measurements and day-to-day variabilities of left ventricular volumes and ejection fraction by three-dimensional echocardiography and comparison with magnetic resonance imaging.

The aim of this study was to assess day-to-day variability of left ventricular (LV) volume and ejection fraction (EF) calculated from 3-dimensional echocardiography (3-DE) and to compare the reproducibility of the measurement with magnetic resonance imaging. Forty-six subjects were examined including 15 normal volunteers (group A) and 31 patients with LV dysfunction (group B). Precordial 3-DE acquisition was performed at 2 degrees rotational intervals and repeated 1 week later. Magnetic resonance imaging was performed at 0.5 T. End-diastolic and end-systolic LV volumes were derived using Simpson's rule by manual endocardial tracing of 8 equidistant parallel LV short-axis slices with 3-DE, whereas 9-mm slices were used with magnetic resonance imaging. The mean +/- SD of end-diastolic and end-systolic LV volumes (ml) and EF (%) from magnetic resonance imaging were 182 +/- 75, 121 +/- 76, and 39 +/- 18, whereas those from 3-DE were 182 +/- 76, 121 +/- 77, and 39 +/- 18 respectively. Day-to-day measurements of end-diastolic and end-systolic LV volumes, and EF on 3-DE were not significantly different as assessed with SEE (2.7, 1.1, and 2.4, respectively). Intra- and interobserver SEE for calculating end-diastolic and end-systolic LV volumes and EF for magnetic resonance imaging were 6.3, 4.7, and 2.1 and 13.6, 11.5, and 4.7, respectively, whereas those for 3-DE were 3.1, 4.4, and 2.2 and 6.2, 3.8, and 3.6, respectively. Day-to-day variability of LV volume and EF calculation on 3-DE were small and not significantly different for normal and dysfunctional left ventricles. Observer variabilities of 3-DE were fewer than those of magnetic resonance imaging. Therefore, 3-DE is recommended for serial assessment of LV volume and EF in normal and abnormally shaped ventricles.

Adult↗
PubMed1998

Endoanal MRI of perianal fistulas: the optimal imaging planes.

Twenty consecutive patients with the clinical suspicion of a perianal fistula were studied to define the optimal and time-efficient imaging planes for endoanal MRI in the identification and classification of perianal fistulas. The duration of each part of the MR procedure was recorded in all patients. Off-axis axial (A), coronal (C), sagittal (S) and radial (R) T2-weighted sequences were performed in all patients. Sets of images and combinations of images (A; R; CS; AR; ACS; ARCS) without patient data were reviewed in masked fashion and independently with a 2-month interval between each set. The reader was masked to the results of previous readings. The findings were compared with the surgical findings. The number of correctly identified and classified fistula and the sensitivity and specificity were determined. Twenty fistulas were present at surgery: 14 transsphincteric fistulas and six intersphincteric fistulas. Eighteen fistulas were correctly identified with the radial (R) and combined coronal sagittal (CS) sequences. In all other sequences or combinations of sequences all 20 fistulas were identified. Classification was correct with A in 16 patients, with R in 15, with CS in 15, with AR in 18, with ACS in 17 and with ARCS in 18. The sensitivity and specificity were optimal using AR or ARCS (0. 86 and 1 respectively). The optimal and most time-efficient imaging protocol for endoanal MRI of perianal fistulas thus comprises the axial and radial imaging planes.

Anal Canal↗
PubMed1998

Female pelvic floor: endovaginal MR imaging of normal anatomy.

PURPOSE: To demonstrate the anatomy of the female pelvic floor with endovaginal magnetic resonance (MR) imaging. MATERIALS AND METHODS: Ten healthy nulliparous volunteers (age, 22-26 years) underwent MR imaging with an endovaginal coil. Findings on endovaginal MR images in the volunteers were correlated with findings on endovaginal MR images and cross-sectional anatomic slices obtained in three cadavers. RESULTS: The endovaginal coil was well tolerated by all volunteers. Pelvic floor structures such as the pelvic diaphragm and the urogenital diaphragm were well depicted. Previously undescribed urethral supporting structures--the periurethral and paraurethral ligaments--were visualized. The zonal anatomy of the urethra was clearly visible. The endovaginal MR imaging findings in the volunteers correlated with the endovaginal MR findings and gross anatomy in the cadavers. CONCLUSION: Endovaginal MR imaging clearly demonstrates the anatomy of the female pelvic floor and urethra.

Adult↗
PubMed1997

Magnetic resonance imaging of the female pelvic floor and urethra: body coil versus endovaginal coil.

The anatomy of the female pelvic floor and urethra is complex. With the introduction of MRI, the discussion about the normal anatomy of this area has not diminished. The use of a body coil may be contributary to this. In the present study images obtained with an endovaginal coil are compared with those of a quadrature body coil series to study the possible advantage of endovaginal imaging. Axial and radial T2-w TSE images at a 1.0-T machine were obtained in seven healthy volunteers. The pelvic floor structures as well as the levator ani muscle and the urogenital diaphragm are excellently demonstrated with the endovaginal coil. Also, the urethrovaginal sphincter could be recognized in six volunteers, but only in three with the body coil. In six volunteers a new ligamentous structure, the urethropelvic sling, connecting the urethra to the levator ani muscle and contributing to the supporting mechanism of the urethra is shown with the endovaginal coil. The zonal anatomy of the urethra is excellently shown with the endovaginal coil. The urethral length could only be accurately measured with this coil and ranged from 3.1 to 3.6 cm. Compared with the body coil, endovaginal MRI is excellent in demonstrating the anatomy of the pelvic floor and urethra.

Adult↗
PubMed1996

Imaging of the anorectal region.

Imaging of anorectal region has drastically changed during the last decade. Transrectal ultrasound and transrectal MRI can be used for staging the rectal tumours. Endoanal sonography can be applied for the classification of perianal fistulae and identification of anal sphincter defects in patients with faecal incontinence. Due to the limitations of endoanal sonography, endoanal MRI was introduced to assess the pathology related to the anal sphincter complex. Endoanal MRI seems superior to endoanal sonography. This paper describes the new developments of the imaging techniques and presents new insights in anatomy and pathology of the anorectum.

Anus Diseases↗
PubMed1996

Fistula in ano: endoanal sonography versus endoanal MR imaging in classification.

PURPOSE: To assess agreement between endoanal sonography, endoanal magnetic resonance (MR) imaging, and surgery in depiction and classification of fistula in ano. MATERIALS AND METHODS: Twenty-eight consecutive patients with nonspecific, cryptoglandular fistula in ano were studied. The fistulas were classified with endoanal sonography, endoanal MR imaging, and surgery. Agreement between the modalities was also evaluated. RESULTS: Classification of fistulas was possible in 17 of 28 patients (61%) with sonography, in 25 of 28 (89%) with MR imaging, and in 26 of 28 (93%) with surgery. Concordance between endoanal sonography and MR imaging occurred in 46% of the cases (kappa = 0.27, poor agreement); between sonography and surgery in 36% (kappa = 0.09, no agreement); and between MR imaging and surgery in 64% (kappa = 0.43, moderate agreement). CONCLUSION: Endoanal MR imaging more accurately allows depiction and classification of fistula in ano than endoanal sonography.

Adult↗
PubMed1996

Endoanal MRI of the anal sphincter complex: correlation with cross-sectional anatomy and histology.

The purpose of this study was to correlate the in vivo endoanal MRI findings of the anal sphincter with the cross-sectional anatomy and histology. Fourteen patients with rectal tumours were examined with a rigid endoanal MR coil before undergoing abdominoperineal resection. In addition, 12 cadavers were used to obtain cross-sectional anatomical sections. The images were correlated with the histology and anatomy of the resected rectal specimens as well as with the cross-sectional anatomical sections of the 12 cadavers. The findings in 8 patients, 11 rectal preparations, and 10 cadavers, could be compared. In these cases, there was an excellent correlation between endoanal MRI and the cross-sectional cadaver anatomy and histology. With endoanal MRI, all muscle layers of the anal canal wall, comprising the internal anal sphincter, longitudinal muscle, the external anal sphincter and the puborectalis muscle were clearly visible. The levator ani muscle and ligamentous attachments were also well demonstrated. The perianal anatomical spaces, containing multiple septae, were clearly visible. In conclusion, endoanal MRI is excellent for visualising the anal sphincter complex and the findings show a good correlation with the cross-sectional anatomy and histology.

Adult↗
PubMed1996

Endoanal magnetic resonance imaging versus endosonography.

INTRODUCTION: A major limitation of anal endosonography is the poor inherent contrast, which is the cause of the cumbersome identification of the longitudinal layer and external sphincter. Endoanal MRI was introduced to overcome this problem. The normal anatomy, perianal fistulas and sphincter defects as visualized by endoanal MRI as compared to endoanal sonography are discussed. MATERIAL AND METHODS: Endoanal sonography was performed with an 18-mm diameter 7-MHz endoanal probe. For endoanal MRI a 19-mm diameter endoanal receiver coil was used at 0.5 T. Volunteers and patients with anal fistula or fecal incontinence were examined with both techniques. RESULTS: Endoanal MRI demonstrates the internal sphincter but also the longitudinal layer and external sphincter in great detail. The external sphincter is the lower outer part of the sphincter, while the puborectal muscle is the upper outer part of the sphincter which is connected to the levator ani muscle. External sphincter defects are more often identified and better delineated with MRI. Endoanal MRI is superior in the identification and classification of perianal fistulas. CONCLUSION: Endoanal MRI is an important new diagnostic tool in anal imaging. The anal sphincter anatomy and pathology are excellently demonstrated. Endoanal MRI is superior to endoanal sonography, especially in the identification of external sphincter defects and in the classification of tracks.

Anal Canal↗