L Van Hoe

Pelvic floor descent in females: comparative study of colpocystodefecography and dynamic fast MR imaging.

The purpose of this study was to compare fast dynamic magnetic resonance imaging (MRI) with colpocystodefecography (CCD) in the evaluation of pelvic floor descent in women. Thirty‐five women with clinical evidence of pelvic floor descent were studied. A fast single‐shot MR sequence was performed in the supine position during pelvic floor relaxation and during maximal pelvic strain. On the same day, a dynamic CCD was performed with the patient seated on a stool‐chair. The degree of descent of the bladder, vagina, and anorectal junction was evaluated as the vertical distance between the pubococcygeal line and the bladder base, the vaginal vault, and the anorectal junction, respectively. A bulge of more than 3 cm measured as the distance between the extended line of the anterior border of the anal canal and the tip of the rectocele was interpreted as a rectocele. MRI was compared with CCD during maximal pelvic strain (CCD I) and during voiding and defecation (CCD II). CCD was considered as the gold standard. Compared with clinical examination, CCD I showed a larger number of involved compartments, except for the middle compartment. CCD II was superior to clinical examination in all cases. In comparison with CCD I and especially CCD II, MRI had a lower sensitivity, especially for the anterior and middle compartment. Even four enteroceles seen on CCD II were not detected by MRI. When CCD I and CCD II were compared, a cystocele, a vaginal vault prolapse, an enterocele, and a rectocele were more readily seen on CCD II than with CCD I. When compared with CCD, supine dynamic MRI is unreliable, especially in the anterior and middle compartment. Even in the detection of enteroceles CCD was superior to MRI. In general, the best results with MRI can be expected for evaluation of the rectum.J. Magn. Reson. Imaging 1999;9:373–377.

18-FDG PET scan in the staging of recurrent melanoma: additional value and therapeutic impact

Staging of melanoma patients by means of whole body functional imaging in a single evaluation session using positron emission tomography (PET) with fluorine-18- labelled deoxy-d-glucose (FDG) as a metabolic tracer has created much interest over the last decade. After enthusiastic pilot studies, more attention has been paid to the false-negative and false-positive results of this technique than to its true therapeutic impact. This study aimed to evaluate (1) the sensitivity and specificity of this technique at a single lesion level compared with conventional screening procedures (CSP) – both of these accompanied by careful clinical examination; and (2) the additional value of the PET scan at the level of the individual patient and its therapeutic impact for different types of melanoma recurrence. A consecutive series of 100 PET scans performed on 84 melanoma patients with regional or distant recurrence according to CSP (89 PET scans) or suspicion of recurrence, i.e. inconclusive CSP (11 PET scans), were retrospectively analysed and compared with the CSP results. At the single lesion level, PET scan and CSP showed a sensitivity of 85 and 81%, a specificity of 90 and 87% and an accuracy of 88 and 84%, respectively. PET provided false-negative results for small skin metastases and brain involvement; false-positive results were associated with unrelated benign or malignant tumours and peripheral soft tissue and bone uptake. PET scan showed an additional value over and above CSP at the individual patients level by true upstaging in 10 cases, true downstaging in 24 cases and depiction of more lesions within the same stage of disease in 15 cases. The overall therapeutic impact reached 26%: 17 out of 71 (24%) cases with regional recurrence, one out of 18 cases (5.5%) with distant metastasis and eight out of 11 cases (73%) with suspicion of recurrence where CSP remained doubtful. However, in 19 cases comparison between CSP and PET resulted in discordant findings, suggesting upstaging in one area and downstaging at another site within the same patient. In conclusion, PET scan has an additional value in the staging of recurrent melanoma, providing it is accompanied by careful clinical examination and specific brain imaging. However, in the absence of evidence of metastasis or unrelated conditions at the same site on CSP, PET spots may represent false-positive images, which would falsely upgrade a patient to an incurable state, or they may be early true-positive findings, which will become evident during close follow-up.

Intrahepatic splenosis: imaging features

We report a patient who presented with asymptomatic focal liver lesions and in whom a diagnosis of intrahepatic splenosis was made. This rare condition mostly occurs in patients who previously underwent splenic trauma or surgery. Magnetic resonance imaging (MRI) characteristics suggesting this diagnosis are described. The lesions were mainly hypointense on T1- and hyperintense on T2-weighted images. After administration of small iron oxide particles (SPIO-Endorem), the lesions remained slightly hyperintense relative to the hypointense liver parenchyma but showed a 50% loss in signal intensity. Knowledge of these MRI characteristics may avoid the use of surgical interventions to arrive at the correct diagnosis of these rare liver lesions.

Evaluation of manual vs semi-automated delineation of liver lesions on CT images

Abstract. In this paper we compare a semi-automated delineation method with totally manual delineation for area quantification, with respect to efficiency, quality, and intra- and interobserver variability. Liver lesions on 28 CT images were delineated by three observers, twice using completely manual delineation and twice using a semi-automated method. Quantitative comparisons were performed with respect to delineated area and time required for the delineation tasks. Subjective comparisons were performed with respect to efficiency and perceived quality of the semi-automated method. The areas obtained using semi-automated delineation were significantly smaller (11 %) than those obtained using totally manual delineation. Intraobserver and interobserver variability with the semi-automated method were approximately three times lower than with manual delineation. Efficiency of the semi-automated method was subjectively rated favorable, although further improvements are possible. With respect to quality, the semi-automated method was ranked better than the manual method in 73 % of cases.

Spiral CT of intracranial aneurysms : correlation with digital subtraction and magnetic resonance angiography

Spiral CT and magnetic resonance angiography (MRA) were performed in ten patients with 14 intracranial aneurysms known from conventional angiography. All lesions, the smallest 3 mm in diameter, were visible on spiral CT and MRA. The neck of the aneurysm and its anatomical relations could very accurately be determined in all cases. Advantages of spiral CT over MRA are: a short acquisition time with reduction of motion artefacts, no dependence on flow rate or cardiac output, and excellent visualisation of calcification, thrombus and bony landmarks. Disadvantages are the necessity for iodinated contrast medium, long postprocessing and reconstruction time and the possibility of overlap of bone and venous blood.

Assessment of accuracy of renal artery stenosis grading in helical CT angiography using maximum intensity projections

The purpose of the study was to investigate whether visual inspection of maximum intensity projection (MIP) images is a reliable method for assessment of the severity of renal artery stenoses (RAS). Therefore, 20 RAS were investigated with helical CT. Native axial images and MIP images were analysed separately or in combination (“two-step method”). A phanton study was performed to investigate the influence of window setting on apparent stenosis severity. Accuracy for diagnosis of 50–69% and 70–99% RAS and the mean inter-observer agreement were 82.5%, 77.5% and 82.5% respectively, using study of MIP images alone, and 100%, 97.5% and 95% using the “two-step method”. The phantom study showed that the apparent severity of vascular stenoses on MIP images depends on the selected window centre values. It is concluded that combined evaluation of both MIP images and native axial images is more reliable than study of MIP images alone for assessing the severity of RAS.

MR imaging findings in two patients with hepatic veno-occlusive disease following bone marrow transplantation

Abstract. The aim of this study was to describe the MRI features of veno-occlusive disease (VOD) following bone-marrow transplantation in two patients. The MRI features consisted of hepatomegaly, hepatic vein narrowing, periportal cuffing, gallbladder wall thickening, marked hyperintensity of the gallbladder wall on T2-weighted images, ascites, and pleural effusion. In one patient, signs of reduced portal venous flow velocity were also observed. It is concluded that the use of MRI as a complementary technique following non-conclusive US examination enabled a timely diagnosis of this life-threatening disease in both patients.

Epithelioid hemangioendothelioma of the liver

Epithelioid hemangioendothelioma of the liver is a rare vascular tumor with intermediate malignant potential. On imaging studies, the lesion has a solid appearance and may mimic metastatic disease. We present a case in which the morphologic features (multifocal aspect, peripheral location, and capsular retraction) and the clinical history aided in including this entity in the differential diagnosis.

Case report: pseudotumoral pelvic retroperitoneal fibrosis associated with orbital fibrosis

We report the case of a man with bilateral orbital fibrous pseudotumours and a large pelvic mass which was initially thought to be malignant. Sonographically guided transrectal core biopsies showed it to be a fibrotic retroperitoneal pseudotumour. The mass decreased after steroid therapy. The computed tomography and magnetic resonance imaging features of this unusual form of pelvic fibrosis as well as the association with heterotopic fibrosis are discussed.

CT findings in nonmucosal eosinophilic gastroenteritis

A 22-year-old patient with eosinophilic gastroenteritis with predominantly submucosal and muscular involvement is presented. The benefits of CT, using water as an orally administered contrast agent, are stressed, because CT enabled the authors to suggest a full thickness biopsy, after mucosal biopsies had remained repeatedly negative.