PubMed Health⌕ Search

Biomedical subjects

J H Ruijs

Publications and source records attributed to J H Ruijs.

At least 19 recordsLinked to original sources
PubMed1997

False-negative MR imaging of malignant breast tumors.

In this study we analyze MR-negative malignant lesions of the breast. A total of 204 patients with palpable and/or mammographic lesions were studied. The MR technique consisted of the turbo FLASH and MP-RAGE subtraction techniques. All patients underwent surgical biopsy and/or mastectomy and all specimens were examined by the correlative radiologic-histologic mapping technique. A total of 208 lesions were evaluated; 145 turned out to be malignant and 63 proved to be benign. Six malignant lesions were misinterpreted as benign on MR imaging; thus, suspicious contrast enhancement was present in 96 % of the lesions detected by mammography, US, or clinical examination. Especially 4 of the 17 ductal carcinoma in situ (DCIS) lesions were misinterpreted (23.5 %). Despite optimal technique, 6 malignant lesions were not identified by MR imaging. The highest prevalence of these MR occult lesions was in the group of DCIS. Although MR imaging has an important role in the evaluation of breast lesions and, primarily, in ruling out malignancy, one should be aware of the fact that false-negative MR findings do occur.

Breast↗
PubMed1997

Imaging of vascular pathology in hyperhomocysteinemic patients with digital subtraction angiography and magnetic resonance techniques.

Mild hyperhomocysteinaemia (mHH) is an independent risk factor for premature arteriosclerosis. We investigated the accuracy in the detection of early arteriosclerotic lesions in such patients. The left and right wall of the abdominal aorta, the aortic bifurcation and both common iliac arteries were evaluated with gated T1-weighted magnetic resonance imaging (gT1 MRI) and gated two-dimensional (2D) time-of-flight magnetic resonance angiography (g2D-TOF MRA) and were compared with intra-arterial digital subtraction angiography (iaDSA) in 11 patients with arteriosclerosis and mHH. Six patients showed arteriosclerosis in one or more of the total number of 55 studied arterial segments with iaDSA. Thirty-two of 37 normal and 12 of 18 stenotic segments with gT1 MRI, and 29 normal and 6 stenotic segments with g2D-TOF MRA, were correctly classified. Sensitivity of gT1 MRI and g2D-TOF MRA versus iaDSA was 67 and 33 %, the specificity was 86 and 78 % and the accuracy was 80 and 64 %, respectively. We conclude that arteriosclerosis in patients with mHH is a regular finding, and gT1 MRI in such patients is an acceptable technique.

Adult↗
PubMed1997

What is new in bladder cancer imaging.

Treatment and prognosis of urinary bladder cancer largely are determined by the tumor stage and presence of metastases. MR imaging and clinical staging complement each other. MR imaging is the most accurate technique for differentiating the various stages of deep tumor infiltration and detection of metastases, whereas clinical staging is the best technique for differentiating between postbiopsy effects and the various stages of superficial tumors. The role of MR imaging in staging of this disease and monitoring of therapy is reviewed and illustrated. Finally, the authors present an overview of current and future applications of this technique.

Carcinoma, Transitional Cell↗
PubMed1996

Primary staging of urinary bladder carcinoma: the role of MRI and a comparison with CT.

Since the introduction, pelvic MRI has been considered the best non-invasive technique for primary staging of urinary bladder cancer. Before using MRI an understanding of normal and pathological MR images of the urinary bladder is essential. This review therefore describes the MR anatomy of the urinary bladder as well as the appearances of carcinoma. MRI plays an important clinical role in staging the primary tumour. In superficial tumours, clinical staging, which includes transurethral biopsy, is the best technique. For invasive tumours, MRI is superior to other techniques such as CT scanning, transvesical ultrasonography and clinical staging. A limitation of both MRI and CT scanning is their inability to recognize minimal tumour growth in the muscle layer of the bladder wall, or to differentiate between post-transurethral resection oedema and tumour. Therefore, in all patients with urinary bladder cancer staging should preferably start with MRI followed by clinical staging. Unfortunately, however, because of the high cost of this strategy, MRI has to be reserved for staging deeply invasive and superficial poorly differentiated tumours.

Biopsy↗
PubMed1995

Mandibulofacial dysostosis: CT findings of the temporal bones.

Six patients of two families with clinically suspected and genetically proven Treacher Collins syndrome and hearing loss were studied by CT of the temporal bone. The objective of this study was to detect the abnormalities and to show the variation of expression of abnormalities. We found a high incidence of asymmetry in the different ear malformations and a slightly lower incidence of some other classical features, probably due to our patient selection.

Adult↗
PubMed1992

Yearly chest radiography in the early detection of lung cancer following laryngeal cancer.

In a retrospective study of 556 patients (505 men, 51 women) with laryngeal cancer the incidence and prognosis of lung malignancies was studied in patients who were examined yearly by chest radiography. In 69 patients (12.4%) a lung malignancy was diagnosed, with 28 having a histologically confirmed second primary malignancy. All of these 69 patients were men. The incidence of radiologically detected lung malignancies, both second primary and metastatic cancer, is higher and more prolonged following supraglottic carcinoma than following glottic carcinoma. In 47 patients (68%) without symptoms, the lung malignancy was detected by routine annual chest radiography. The survival rate in patients with lung cancer detected by the yearly radiography was significantly higher than in patients diagnosed after symptoms (median survival 10 and 4 months, respectively). However, taking into account the lead time between early radiologic diagnosis and the time a tumor would have been diagnosed following symptoms, the observed survival benefit of yearly radiography was much lower, or even nil.

Actuarial Analysis↗
PubMed1992

ROC curves for the initial assessment of new diagnostic tests.

New diagnostic tests are mainly evaluated by determining the sensitivity and specificity of the test. These test characteristics were originally meant to be used in making diagnoses. For evaluative purposes their usefulness is weakened by their susceptibility to selection and their dependence on the cut-off points that are used for test positivity. The plotting of a receiver operating characteristic (ROC) curve might be a solution to these problems. Furthermore, the ROC curve yields a measure for the diagnostic power of the test expressed in one number instead of two, namely the area under the curve (AUC). Finally, the ROC curve and its AUC permit easy comparison of different tests and the performance of different interpreters of one test. The construction and use of ROC curves are described and illustrated with data of a case-referent investigation into the relationship between iron status parameters and the presence of acute myocardial infarction. The AUCs of ferritin and serum iron, 0.61 and 0.68 respectively, are too low to suggest meaningful usefulness in clinical practice.

Humans↗
PubMed1988

Abdominal fat depots measured with computed tomography: effects of degree of obesity, sex, and age.

Computed tomography scans at the level of L4/L5 were analysed in 66 men and 34 women who presented for routine tomography, stratified into different age categories. Areas of intra-abdominal fat and subcutaneous abdominal fat were calculated from the scans. In men and in women the proportion of the body surface as intra-abdominal fat increased with age (in men from 12.4 per cent in the age group less than 40 years to 18.0 per cent in the age group greater than 65 years; in women from 10.5 per cent to 14.7 per cent in the respective age categories). Only in men this increase with age was independent of the degree of obesity. In women younger than 40 years the proportion of intra-abdominal fat did not increase with increasing BMI while it did in older women and men. The proportion of intra-abdominal fat in 7 adolescents appeared to be 5.4 per cent, considerably lower compared to adult men and women. Subcutaneous fat areas increased with the degree of obesity but not with age. From simple anthropometric measurements, the intra-abdominal fat area was best correlated with the waist circumference in all ages (except for women younger than 40 years) while it showed weaker associations with abdominal skinfolds and circumference ratios. Age and BMI explained 68 and 74 per cent of the variance in intra-abdominal fat area in men and women respectively. Waist added 8 per cent to the explained variance in men but nothing in women. BMI and waist circumference showed similar correlations to total, intra-abdominal and subcutaneous fat areas in all age categories whereas correlations of skinfolds with intra-abdominal fat areas decreased with age.

Abdomen↗