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Biomedical subjects

L Van Hoe

Publications and source records attributed to L Van Hoe.

At least 19 recordsLinked to original sources
PubMed2002

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 patient's 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.

Adult↗
PubMed2001

Autoimmune pancreatitis associated with primary sclerosing cholangitis: MR imaging findings.

Autoimmune pancreatitis is a relatively rare type of chronic pancreatitis that may be associated with other autoimmune disorders. The imaging features of this entity may be misleading and suggest the presence of a malignant tumour. We present a case in which MR imaging allowed us to diagnose autoimmune pancreatitis associated with primary sclerosing cholangitis, which is another autoimmune-related disease. Typical MR characteristics of autoimmune pancreatitis include focal or diffuse enlargement of the pancreas, the absence of parenchymal atrophy and significant dilation proximal to the site of stenosis, the absence of peripancreatic spread, the clear demarcation of the lesion and the presence of a peripancreatic rim.

Autoimmune Diseases↗
PubMed2000

Three-dimensional imaging of acetabular dysplasia: diagnostic value and impact on surgical type classification.

OBJECTIVE: To investigate the diagnostic value and the impact on surgical type classification of three-dimensional (3D) images for pre-surgical evaluation of dysplastic hips. MATERIALS AND METHODS: Three children with a different surgical type of hip dysplasia were investigated with helical computed tomography. For each patient, two-dimensional (2D) images, 3D, and a stereolithographic model of the dysplastic hip were generated. In two separate sessions, 40 medical observers independently analyzed the 2D images (session 1), the 2D and 3D images (session 2), and tried to identify the corresponding stereolithographic hip model. The influence of both image presentation (2D versus 3D images) and observer (degree of experience, radiologist versus orthopedic surgeon) were statistically analyzed. The SL model choice reflected the impact on surgical type classification. RESULTS: Image presentation was a significant factor whereas the individual observer was not. Three-dimensional images scored significantly better than 2D images (P=0.0003). Three-dimensional imaging increased the correct surgical type classification by 35%. CONCLUSION: Three-dimensional images significantly improve the pre-surgical diagnostic assessment and surgical type classification of dysplastic hips.

Acetabulum↗
PubMed2000

Effectiveness of imaging studies in acute appendicitis: a simplified decision model.

Computed tomography (CT) and ultrasonography (US) have been proposed as non-invasive diagnostic aids in patients with suspected acute appendicitis. Currently, clear guidelines about the indications to use these techniques are lacking. Using the concepts of decision analysis, a model was created to calculate the effectiveness of US and CT in patients with clinically suspected appendicitis. The perspective chosen was the health of individual patients. The model makes use of published data and provides a critical threshold probability (ctp). Decisions in individual cases can be made by comparing ctp with the clinical probability of disease. The calculated ctp-values for US and CT were 0.58 and 0.74, respectively. In other words, on average, US (CT) is indicated only if the expert clinician considers the probability of disease to be smaller than 58% (74%). It is concluded that in patients with suspected acute appendicitis, selective rather than routine use of imaging studies is recommended. The exact value of the decision threshold should be determined in function of the local situation.

Acute Disease↗
PubMed2000

Breath-hold contrast-enhanced three-dimensional MR angiography of the abdomen: time-resolved imaging versus single-phase imaging.

PURPOSE: To evaluate a technique for time-resolved breath-hold contrast material-enhanced three-dimensional magnetic resonance (MR) angiography of the abdomen. MATERIALS AND METHODS: In a prospective study, 43 patients underwent time-resolved MR angiography (acquisition time per data set, 7 seconds). The patients also underwent single-phase high-spatial-resolution MR angiography (acquisition time, 27 seconds) (n = 6), conventional angiography (n = 7), or both (n = 30). No bolus timing study was performed for time-resolved MR angiography. Image quality (presence of artifacts, ability to prevent venous overlap on arterial phase images, contrast enhancement) and demonstration of anatomic variants (renal arterial and venous variants, vena caval anomaly, visceral arterial variants) and vascular diseases were assessed. RESULTS: Time-resolved MR angiographic images were characterized by fewer and less severe artifacts, less overlap of enhancing veins, and better contrast enhancement than were single-phase MR angiographic images (P < .05). The mean sensitivity and specificity were 90% (nine of 10) and 100% (1 73 of 1 73), respectively, for detection of arterial anatomic variants and 93% (28 of 30) and 100% (324 of 325), respectively, for detection of disease. The technique also proved to be reliable for demonstration of venous disease. CONCLUSION: In comparison with current non-time-resolved MR angiographic techniques, time-resolved MR angiography is more robust and easier to perform and allows simultaneous evaluation of arterial and venous disease.

Abdomen↗
PubMed1999

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 1) 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.

Adult↗
PubMed1999

Time-resolved MR angiography of the upper abdomen: initial clinical experience.

In this study, thirty-eight patients with a variety of upper abdominal diseases were examined with three-dimensional time-resolved MR angiography (7 sec/data set). Visualisation of arterial and venous anatomy was excellent in the majority of patients. Moreover, subtraction images could be calculated and organ perfusion could be assessed. It is concluded that this technique opens new perspectives for a comprehensive evaluation of vascular and parenchymal disease.

Abdomen↗
PubMed1999

Screening applications for MRI in the detection of upper abdominal disease: comparative study of non-contrast-enhanced single-shot MRI and contrast-enhanced helical CT.

PURPOSE: To compare the value of 'push-button' single-shot non-contrast-enhanced MRI and contrast-enhanced helical CT for detection of upper abdominal disease. METHODS: In 120 patients, images obtained with non contrast-enhanced single-shot MRI (T2: double echo HASTE, and T1: turbo FLASH) and contrast-enhanced helical CT were compared. Lesions or abnormalities were divided in 8 anatomical categories (1: liver; 2: pancreatobiliary; 3: kidney/adrenal gland; 4: retroperitoneum; 5: vascular; 6: spleen; 7: gastrointestinal tract and peritoneum; 8: base of thorax) and classified as follows: 2: seen at MRI only; 1: better seen at MRI; 0: no difference; -1: better seen at CT; -2: seen at CT only. Also recorded were the 'door-to-door' examination times. RESULTS: Of a total of 629 abnormalities, 594 were detected at MRI (94 %) and 536 at CT (85 %). CT offered better results in two categories only: retroperitoneum (mean score: -0.68) and vascular (mean score -0.87). Mean examination times were 19 min for CT and 14.8 min for MRI. CONCLUSION: Unenhanced single-shot MRI is a valuable first step of a comprehensive upper abdominal MR exam and may even be the final step in many patients.

Abdomen↗
PubMed1999

Cervical carcinoma: optimized local staging with intravaginal contrast-enhanced MR imaging--preliminary results.

Ten patients suspected of having cervical carcinoma underwent magnetic resonance (MR) imaging before and after opacification of the vagina with a mixture of barium, water, and maltodextrin/calcium lactate. Use of vaginal contrast medium resulted in improved visualization of the vaginal wall, lumen, and fornices in all patients and in a change in local tumor stage in two patients (20%). This technique may contribute to improved noninvasive staging of cervical carcinoma.

Adult↗
PubMed1999

Additional value of whole-body positron emission tomography with fluorine-18-2-fluoro-2-deoxy-D-glucose in recurrent colorectal cancer.

PURPOSE: To assess the additional value of the whole-body [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) scan as a staging modality complementing conventional diagnostic methods (CDM) in patients suspected of having recurrent colorectal adenocarcinoma. PATIENTS AND METHODS: In 103 patients, the discordances between FDG-PET and CDM results were identified and related to the final diagnosis obtained by histopathology or clinical follow-up (> 1 year). All FDG-PET studies were reviewed with full knowledge of the CDM findings. RESULTS: In a region-based analysis, discordances between CDM and FDG-PET findings were found in 40 of 412 regions (10%). In these, FDG-PET had additional diagnostic value in 14 of 16 locoregional, six of seven hepatic, seven of eight abdominal, and eight of nine extra-abdominal regions. In a patient-based analysis, CDM categorized a subgroup of 60 patients as having resectable recurrent disease limited to the liver (n = 37) or locoregional region (n = 23). In 13 of these patients, there were discordant FDG-PET findings, detecting additional tumor sites in nine patients and excluding disease in three patients and yielding an additional diagnostic value in 20% of the patients. A second subgroup consisted of 13 patients with inconclusive CDM findings (n = 5) or with elevated plasma carcinoembryonic antigen levels and an otherwise negative conventional work-up (n = 8). In these patients, FDG-PET results were correct in eight of nine discordances, yielding a positive additional diagnostic value in 62% of the patients. CONCLUSION: Whole-body FDG-PET can have a clear impact on the therapeutic management in the follow-up of patients with colorectal cancer.

Abdominal Neoplasms↗
PubMed1998

Solitary true cyst of the pancreas.

We report a case of a woman diagnosed with a solitary true cyst of the pancreas. CT and especially MRI guided us in the diagnosis of this benign lesion. The cyst has been surgically removed because of secondary bile-duct obstruction causing painless jaundice. Clinical history, laboratory, imaging, and histological findings are reported.

Cholestasis↗