Biomedical subjects

J A Castelijns

Publications and source records attributed to J A Castelijns.

At least 55 records · Page 3Linked to original sources

PubMed1998

Diagnostic evaluation of the neck.

Modern imaging for neck node metastases has increased our ability to predict the presence of palpably occult metastases and predict the resectability of large metastases. The accuracy of CT scans, MR imaging, but especially US-FNAC, has increased to such an extent that clinical consequences are being attached to negative radiologic findings in a clinically N0 neck. As not all palpably occult metastases can be detected, especially when they are micrometers, follow-up should be strict, with use of US-FNAC in the neck observed instead of treated electively.

Head and Neck Neoplasms↗

PubMed1998

Magnetization transfer contrast (MTC) and long repetition time spin-echo MR imaging in multiple sclerosis.

PURPOSE: To study whether application of magnetization transfer contrast (MTC) improves visibility and detection of multiple sclerosis (MS) lesions on long repetition time (TR) conventional spin-echo (CSE) or fast spin-echo (FSE) magnetic resonance (MR) imaging. MATERIAL AND METHODS: In 20 patients and 5 controls, MR images were obtained using long repetition time CSE and FSE sequences with and without MTC. Signal-to-noise ratios of normal appearing white matter (NAWM) and selected lesions, and contrast-to-noise ratios between lesions and NAWM, were calculated. Lesions were counted and total lesion volume was measured in a blinded fashion for each sequence. RESULTS: In controls, MT effect in white matter (16.3% vs. 12.2%) was higher for CSE than for FSE (p < 0.01). Application of MTC to either CSE or FSE resulted in a significantly lower decrease in signal intensity of NAWM in patients compared to white matter in controls (p < 0.01). Furthermore, in patients signal intensity of lesions was less decreased than signal intensity of NAWM (p < 0.01). Compared to sequences without MTC, contrast-to-noise ratios were significantly higher on both CSE (10.9%) and FSE (6.3%) when MTC was applied (p < 0.01). Despite better visibility, the number of lesions detected on either sequences did not increase when MTC was applied. For CSE with MTC, we found an almost equal number of lesions and for FSE with MTC, we found even less lesions (p < 0.01). Total lesion volume did not change significantly when MTC was applied. CONCLUSION: Although contrast between lesions and NAWM improved when magnetization transfer contrast was applied, this did not increase detection of MS lesions on either CSE or FSE MR imaging.

Adult↗

PubMed1998

Imaging of laryngeal cancer.

CT and MRI are the main modalities for examination of laryngeal pathology. Generally, MRI seems to be the optimal method of examination in cooperative patients, especially for evaluation of their larynx before an attempted partial laryngectomy. The choice between the two modalities will also be determined by one's experience with these modalities. The possibilities of CT and MRI vary clearly from each other regarding detection of cartilage invasion. MRI seems to be more sensitive than CT in detection of neoplastic cartilage invasion, but seems to have a somewhat lower specificity, especially for thyroid cartilage involvement. There are increasing indications for imaging regarding tumor volume, and signs of cartilage involvement may have prognostic significance for the risk of tumor recurrence.

Carcinoma, Squamous Cell↗

PubMed1998

Brain and spinal cord abnormalities in multiple sclerosis. Correlation between MRI parameters, clinical subtypes and symptoms.

We investigated various magnetic resonance MRI parameters for both brain and spinal cord to see if any improved the clinicoradiological correlation in multiple sclerosis. Ninety-one multiple sclerosis patients (28 relapsing-remitting, 32 secondary progressive and 31 primary progressive) were imaged using conventional T1, proton density- and T2-weighted MRI of the brain and spinal cord. Focal brain and spinal cord lesion load was scored, as were diffuse signal abnormalities, brain ventricular volume and spinal cord cross-sectional area. Clinical measures included the expanded disability status scale (EDSS), the functional systems score and a dedicated urology complaint questionnaire. Secondary progressive patients differed from relapsing-remitting and primary progressive patients by a larger number of hypointense T1 lesions in the brain, ventricular enlargement and spinal cord atrophy. Primary progressive patients more often had diffuse abnormalities in the brain and/or spinal cord than did relapsing-remitting and secondary progressive patients. In the entire study population, EDSS correlated with both brain and spinal cord MRI parameters, which were independent. The urological complaint score correlated only with spinal cord MRI parameters. In relapsing-remitting and secondary progressive multiple sclerosis, the correlation between MRI and clinical parameters was better than in the entire population. In this subgroup EDSS variance could be explained best by T1 brain lesion load, ventricle volume and spinal cord cross-sectional area. In the primary progressive subgroup the clinicoradiological correlation was weak for brain parameters but was present between spinal cord symptoms and spinal cord MRI parameters. In conclusion, the different brain and spinal cord MRI parameters currently available revealed considerable heterogeneity between clinical subtypes of multiple sclerosis. In relapsing-remitting and secondary progressive multiple sclerosis both brain and spinal cord MRI may provide a tool for monitoring patients, while in primary progressive multiple sclerosis the clinicoradiological correlation is weak for brain imaging.

Adult↗

PubMed1998

Symptoms and signs related to the trigeminal nerve: diagnostic yield of MR imaging.

PURPOSE: To assess the diagnostic yield of magnetic resonance (MR) imaging in patients with symptoms and signs related to the trigeminal nerve. MATERIALS AND METHODS: Medical records and MR imaging studies in 112 consecutive patients referred for MR imaging over 5 years were evaluated. MR images were independently reviewed by two neuroradiologists unaware of the clinical findings. Signs and symptoms at presentation were associated with either a positive or negative MR imaging outcome. Logistic regression analysis was performed to identify clinical variables related to imaging results. RESULTS: Sixty-eight (61%) patients had positive MR imaging findings related to symptoms and signs. Trigeminal neuralgia was correlated with a negative MR imaging outcome (P < .001). Numbness (P < .01), impaired sensation (P < .001), other neurologic symptoms and signs (P < .01), progression of symptoms and signs (P < .001), and duration of symptoms of less than 1 year (P < .001) corresponded to a positive MR imaging outcome. Two regression models, each with three clinical parameters (progression, duration < 1 year, and trigeminal neuralgia or impaired sensation), had comparable accuracy for prediction of the MR imaging outcome. CONCLUSION: Clinical findings can be used to identify groups in which a high or a low yield of MR imaging is correlated with symptoms and signs related to the trigeminal nerve.

Cranial Nerve Diseases↗

PubMed1998

Sagittal MR of multiple sclerosis in the spinal cord: fast versus conventional spin-echo imaging.

PURPOSE: We compared conventional spin-echo (CSE) with fast spin-echo (FSE) dual-echo MR images to determine which of these sequences was better able to depict spinal cord abnormalities in patients with multiple sclerosis (MS). METHODS: CSE and FSE dual-echo MR images were obtained in 37 patients with MS and in six healthy control subjects, all of whom were examined on a 1.0-T MR unit with a phased-array coil and cardiac triggering. Two blinded interpreters graded the MR studies, first separately and then by consensus. Images were scored for presence of artifacts, number of focal lesions, and presence of a diffuse increase in signal intensity. RESULTS: No abnormalities were seen in the volunteers. The CSE sequences were significantly less hindered by MR imaging artifacts than were the FSE sequences. Interobserver agreement was slightly higher for the CSE than the FSE sequences. After reaching a consensus, the observers found that both CSE and FSE techniques enabled detection of approximately the same number of focal lesions; however, in three patients, small single lesions seen on the CSE images were missed on the FSE images. Also, depiction of a diffuse increase in signal intensity was better on the CSE images. As a result, more patients had abnormal findings on the CSE sequences than on the FSE sequences (35 versus 31). CONCLUSION: Cardiac-triggered dual-echo FSE sequences are almost as good as CSE sequences for depicting spinal MS lesions. Therefore, in cases of established spinal MS, FSE techniques may be as effective as CSE techniques. Because sensitivity for subtle abnormalities is lower with FSE imaging, CSE remains the preferred technique for patients with suspected MS of the spinal cord.

Adult↗

PubMed1998

Patterns of lesion development in multiple sclerosis: longitudinal observations with T1-weighted spin-echo and magnetization transfer MR.

PURPOSE: We evaluated the appearance of enhancing multiple sclerosis (MS) lesions on unenhanced T1-weighted MR images and the natural course of enhancing MS lesions on serial unenhanced T1-weighted and magnetization transfer (MT) MR images. METHODS: One hundred twenty-six enhancing lesions were followed up monthly for 6 to 12 months to determine their signal intensity on unenhanced T1-weighted and MT MR images. At the time of initial enhancement, the size of the lesion and the contrast ratio of enhancement were calculated for each enhancing lesion. During follow-up, the contrast ratio on the corresponding unenhanced T1-weighted image was measured, and an MT ratio (MTR) was calculated. RESULTS: Twenty-five enhancing lesions (20%) appeared isointense and 101 lesions (80%) appeared hypointense relative to normal-appearing white matter on unenhanced T1-weighted images. During 6 months of follow-up, four MR patterns of active lesions were detected: initially isointense lesions remained isointense (15%); initially isointense lesions became hypointense (5%, most of which reenhanced); initially hypointense lesions became isointense (44%); and initially hypointense lesions remained hypointense (36%). MTR was significantly lower for hypointense lesions as compared with isointense lesions at the time of initial enhancement. For lesions that changed from hypointense to isointense, MTR increased significantly during 6 months of follow-up. Multiple regression analysis showed that strongly decreased MTR at the time of initial enhancement and enhancement duration of more than one scan were predictive of a hypointense appearance on unenhanced T1-weighted images at 6 months' follow-up. Ring enhancement was found to be the only (weak) predictor of persistently hypointense signal intensity. CONCLUSION: Most enhancing lesions appear slightly to significantly hypointense on unenhanced T1-weighted images. Although most hypointensities are reversible, only those lesions that fail to recover on unenhanced T1-weighted and MT images may have considerable irreversible structural changes.

Adolescent↗

PubMed1998

The size of lymph nodes in the neck on sonograms as a radiologic criterion for metastasis: how reliable is it?

PURPOSE: A definition of cut-off points for nodal size is essential to determine whether cervical lymph nodes are metastatic or not. Because the currently used size criteria are defined for random populations of patients with head and neck cancer, we set out to study whether these criteria are optimal for patients without palpable metastases in different levels of the neck We defined optimal size criteria for sonography by calculating the sensitivity and specificity of different size cut-off points. METHODS: We compared the sensitivity and specificity of different size cut-off points as measured on sonograms for various levels in the neck in a series of 117 patients with and 131 patients without palpable neck metastases. RESULTS: A minimum axial diameter of 7 mm for level II and 6 mm for the rest of the neck revealed the optimal compromise between sensitivity and specificity in necks without palpable metastases. For all necks together (with and without palpable metastases), the criteria were 1 to 2 mm larger. CONCLUSION: Our findings indicate that the current sonographic size criteria used for random patient populations are not optimal for necks without palpable metastases, nor can the same cut-off points be used for all levels in the neck.

Evaluation Studies as Topic↗

PubMed1997

Comparison of four potential MR parameters for severe tissue destruction in multiple sclerosis lesions.

The purpose of this study was, first, to evaluate correlations between four potential magnetic resonance (MR) parameters for severe tissue destruction in multiple sclerosis (MS) lesions. Second, to evaluate the effect of incidental magnetization transfer (MT) effect on hypointense lesions in multislice T1 spin echo (SE) imaging. In 49 lesions, from 10 MS patients, MT ratio (MTR), T1 relaxation time, signal intensity (SI) on T1-weighted SE images normalized to normal-appearing white matter (NAWM), and SI normalized to cerebrospinal fluid (CSF) were measured. Differences in contrast of hypointense lesions were measured between single slice and multislice imaging. MTR correlated significantly (p < .001) with longitudinal relaxation rates (1/T1) (r = 0.84), SI normalized to NAWM (r = 0.78), and SI normalized to CSF (r = 0.75). The degree of reduction in contrast, caused by multislice imaging, correlated significantly with MTR of lesions (r = 0.60, p < .001), leading to reduction of hypointense lesion load (p < .01). We conclude that all four MR markers for severe tissue destruction are highly correlated when applied to selected hypointense lesions on T1-weighted SE images. Due to "incidental" off-resonance excitation, contrast and hypointense lesion load will be reduced in multislice T1-weighted SE images.

Adult↗

PubMed1997

Trigeminal neuralgia: comparison of two MR imaging techniques in the demonstration of neurovascular contact.

PURPOSE: To compare two magnetic resonance (MR) imaging techniques for demonstration of vascular contact with the trigeminal nerve. MATERIALS AND METHODS: Thirteen patients with unilateral trigeminal neuralgia and 50 control subjects underwent three-dimensional fast inflow with steady-state precession (FISP) and contrast material-enhanced magnetization-prepared rapid acquisition gradient-echo (MP-RAGE) MR imaging. The images were independently reviewed by two neuroradiologists, who were blinded to the clinical details. Six of the 13 patients underwent surgery. RESULTS: Vascular contact with the trigeminal nerve at the root entry zone was seen on FISP images in 10 of 13 (77%) symptomatic nerves and in eight of 113 (7%) asymptomatic nerves (P < .001). MP-RAGE and FISP images demonstrated arterial contacts equally well. MP-RAGE images demonstrated one additional venous contact at the root entry zone in a patient with ipsilateral trigeminal neuralgia. Interobserver agreement was good for both FISP (kappa = 0.69) and MP-RAGE (kappa = 0.78) images. The presence of vascular contact at the root entry zone, seen on preoperative MR images, was confirmed in all six patients who underwent surgery. CONCLUSION: Both FISP and MP-RAGE MR imaging are useful in demonstrating vascular contact with the trigeminal nerve at the root entry zone in patients with trigeminal neuralgia.

Case-Control Studies↗

PubMed1997

Single-dose gadolinium with magnetization transfer versus triple-dose gadolinium in the MR detection of multiple sclerosis lesions.

PURPOSE: To compare the efficacy of single-dose gadolinium with magnetization transfer contrast (MTC) with that of triple-dose gadolinium in detecting enhancing multiple sclerosis lesions. METHODS: Twenty-one patients with multiple sclerosis were examined with MR imaging first with 0.1 mmol/kg gadolinium (single dose) and then, after 24 to 72 hours, with 0.3 mmol/kg gadolinium (triple dose). T2-weighted fast spin-echo and T1-weighted spin-echo MR images with and without MTC were obtained before contrast administration followed by either T1-weighted spin-echo images with MTC (single dose) or conventional T1-weighted spin-echo images (triple dose), starting 5, 17, and 29 minutes after contrast administration. All images were evaluated in a blinded fashion and scored in random order by two readers. Outcome parameters included number of enhancing lesions, number of active MR examinations (those containing at least one enhancing lesion), contrast ratio (signal intensity of enhancing lesion divided by signal intensity of normal-appearing white matter), and size of enhancing lesions. RESULTS: Eighty-one percent more enhancing lesions and 49% more active MR examinations were detected when a triple dose of gadolinium was used as compared with a single dose. The level of agreement between readers as to the number of enhancing lesions was significantly higher for triple-dose than for single-dose gadolinium. With triple-dose gadolinium, contrast ratios and areas of enhancement increased by 10% and 33%, respectively. Delayed imaging increased the size of the lesion by 11% on single-dose MTC images and by 18% on triple-dose images. CONCLUSION: Triple-dose gadolinium is more effective (higher sensitivity and interobserver agreement) than single-dose gadolinium in combination with MTC in detecting enhancing multiple sclerosis lesions.

Adult↗

PubMed1996

Impact of cartilage invasion on treatment and prognosis of laryngeal cancer.

Invasion of laryngeal cartilage has long been considered as a contraindication to radiation treatment and to all types of conservation surgery. With the advent of axial imaging techniques clarification of the submucosal extent of disease became possible. However, controversies regarding diagnosis (preferred modality, accuracy of detection of cartilage invasion) and treatment of cartilage invasion (Is cartilage invasion really a contraindication for irradiation treatment?) arose. Based on currently accepted criteria, CT appears to be more specific in detecting neoplastic cartilage invasion than MRI, but tends to underestimate invasion and may therefore result in undertreatment. Magnetic resonance has a higher sensitivity than CT for detection of cartilage invasion. The superiority of MRI lies in its ability to detect intracartilaginous tumor spread. Unfortunately, MR findings suggesting neoplastic cartilage invasion may be false positive in a considerable number of instances. Two MRI-dependent parameters appear to be significant as a prognostic factor for success of radiation therapy: tumor volume and abnormal MR signal pattern in cartilage. Minimal abnormal MR signal patterns in cartilage in patients with small tumors (under 5 cc) does not appear to be a very ominous finding for tumor recurrence after radiation therapy. On the other hand, abnormal MR signal pattern in cartilage combined with large tumor volume (above 5 cc) appears to worsen the prognosis significantly. If voice conservation surgery is being considered, MR imaging is useful for assessing those structures (such as cartilages) whose involvement would contraindicate partial laryngectomy. Magnetic resonance imaging appears to be the optimal method of examination in cooperative patients. If MRI fails or if it is contra-indicated, CT may still be recommended. The radiologist's experience with CT or MRI also determines the choice between the two modalities.

Contraindications↗

PubMed1996

Disappearance of multiple sclerosis lesions with severely prolonged T1 on images obtained by a FLAIR pulse sequence.

Although the superiority of FLAIR over conventional T2-weighted spin-echo (SE) is still unclear, one potential advantage would be its use in quantitative lesion load measurements. We have observed a potential pitfall regarding the use of FLAIR in image quantification. We report a case where a part of the hyperintense lesions on T2 SE, which was hypointense on T1 SE, subsequently was found to be isointense to brain on FLAIR images. Therefore, quantification of lesion load by means of FLAIR might underestimate the "true" lesion load, as seen on T2 SE.

Brain↗

PubMed1996

The incidence of micrometastases in neck dissection specimens obtained from elective neck dissections.

Although modern imaging techniques become more accurate for the assessment of lymph node metastases in the neck as criteria and technology evolve, micrometastases remain occult with any technique. Even the routine histopathological examination of neck dissection specimens is unable to detect all micrometastases. Because knowledge on the incidence of micrometastases in the clinically NO neck might be of importance for decision making regarding elective treatment, a retrospective study on 96 elective neck dissections was conducted. Meticulous histopathological examination of the neck dissection specimens yielded 3092 lymph nodes of which 67 (2.2%) were tumor-positive. Twenty-six of these 67 lymph node metastases were micrometastases. Of the 36 tumor-positive neck dissection specimens, 21 contained micrometastases. In 9 tumor-positive specimens only micrometastases were found. This high incidence of micrometastases has important implications for the diagnostic work-up, the treatment, and histopathological examination of the NO neck.

Carcinoma, Squamous Cell↗

PubMed1996

Laryngeal carcinoma after radiation therapy: correlation of abnormal MR imaging signal patterns in laryngeal cartilage with the risk of recurrence.

PURPOSE: To correlate abnormal magnetic resonance (MR) imaging signal patterns in cartilage with the effectiveness of radiation treatment. MATERIALS AND METHODS: Eighty previously untreated patients underwent MR imaging and radiation therapy with a curative intent. Cartilage was considered to have an abnormal signal pattern if it had intermediate signal intensity on T1-weighted spin-echo (SE) MR images and high signal intensity on T2-weighted SE MR images. The minimum follow-up was 2 years. RESULTS: Abnormal MR imaging signal patterns of the thyroid cartilage (P < .001; P < .04) were more ominous than those of other cartilage. Abnormal signal patterns in cartilage of patients with small tumors (< 5 cm3 and especially < 1 cm3) were less significant. Abnormal signal patterns in cartilage combined with a large tumor (> 5 cm3) worsened the prognosis significantly (P < .05). CONCLUSION: Abnormal MR imaging signal patterns in cartilage may not indicate a poor prognosis in every case. Abnormal signal intensity in the thyroid cartilage combined with a tumor volume of > 5 cm3, however, appears to indicate an adverse prognosis with regard to tumor recurrence.

Adult↗

PubMed1996

Imaging of the larynx.

CT and MR imaging are the main modalities for examination of laryngeal pathology. In general, MR imaging seems to be the optimal method of examination in cooperative patients, especially for evaluation of their larynx prior to an attempted partial laryngectomy. CT is recommended in patients who may have rapid breathing or coughing or if MR imaging is contraindicated. The choice between the two modalities is also determined by the experience of the radiologist with these modalities. Both techniques are comparable in delineating site and extent of pathology in fat and muscular tissue. MR imaging is more sensitive than CT in detecting pathologic involvement of the cartilages. CT and MR imaging are helpful in characterization of cartilaginous tumors and benign lesions, such as laryngoceles and cysts. CT is used to assess the integrity of the laryngeal skeleton in patients who suffered from trauma, that is, for identification of occult fractures, dislocations of cartilages, or confirmation of suspected laryngeal injuries.

Humans↗

PubMed1996

Imaging of cervical lymphadenopathy.

Imaging of the neck is important to diagnose occult lesions and stage the neck in cancer patients and, to a lesser extent, help differentiate swellings in the neck. Furthermore, extension of tumors can be depicted, although assessment of operability is not very reliable. Conventional imaging techniques, such as CT, MR imaging, and US, are rapidly evolving by improvement of spatial resolution and contrast, reduction of artifacts, and development of new contrast agents. Unreliable criteria for metastases, such as size and shape, will be replaced in the future by the depiction of the microstructure inside lymph nodes and the development of specific contrast agents. US-guided aspiration is currently one of the most accurate techniques to assess occult metastases as it overcomes the criteria used by CT, MR imaging, or US without aspiration. It should be noted, however, that approximately 25% of electively operated sides of the neck contain exclusively metastases smaller than 3 mm, limiting the sensitivity in these necks to 75% for all imaging modalities. New imaging modalities, such as immunoimaging with SPECT, thallium SPECT, PET, and fused images, are rapidly developing. Although these techniques will probably become very accurate for the staging of the neck, it is doubtful whether they will be used routinely to stage the neck because of the issues of cost and availability. Their role will probably be more in the detection of unknown primaries, distant metastases, and follow-up, after radiotherapy in case of clinical doubt.

Head and Neck Neoplasms↗

PubMed1996

Comparison of two MR sequences for the detection of multiple sclerosis lesions in the spinal cord.

PURPOSE: To compare cardiac-triggered dual-echo spin-echo and magnetization transfer-prepared gradient-echo (MT-GE) MR imaging in the detection of multiple sclerosis (MS) lesions in the spinal cord. METHODS: The cervical spinal cord in 20 patients with MS and in nine healthy volunteers was examined with spin-echo and MT-GE MR imaging. Sagittal images were scored for number of lesions, certainty about lesions, image quality, and visual hindrance by artifacts in random order by two radiologists separately and in a blinded manner. RESULTS: In one healthy volunteer, a lesion was seen on images obtained with both images. Lesion/cord contrast-to-noise ratio was equal on both the MT-GE and T2-weighted spin-echo images. MT-GE images showed better image quality and fewer artifacts than the spin-echo images did. The readers found approximately the same number of lesions. However, the number of definite lesions was higher for the spin-echo sequence than for the MT-GE sequence. One reader found 45 definite lesions with spin-echo and 34 definite lesions with MT-GE. For the other reader, these numbers were 37 (spin-echo) and 31 (MT-GE). On the spin-echo images, 90% of the patients were considered to have definite lesions; on the MT-GE images, the readers found definite lesions in 65% (reader 1) and in 70% (reader 2) of the patients. CONCLUSION: Image quality was better with the MT-GE technique than with the spin-echo technique, and lesion/cord contrast-to-noise ratio on the MT-GE images was equal to that of T2-weighted spin-echo images. However, for detecting spinal cord MS lesions in the sagittal plane, the spin-echo images were preferred to the MT-GE images.

Adult↗