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  • 1
    ISSN: 1432-1084
    Keywords: Key words: Multiple sclerosis ; MR imaging ; Spinal cord
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The current optimal imaging protocol in spinal cord MR imaging in patients with multiple sclerosis includes a long TR conventional spin-echo (CSE) sequence, requiring long acquisition times. Using short tau inversion recovery fast spin-echo (fast STIR) sequences both acquisition time can be shortened and sensitivity in the detection of multiple sclerosis (MS) abnormalities can be increased. This study compares both sequences for the potential to detect both focal and diffuse spinal abnormalities. Spinal cords of 5 volunteers and 20 MS patients were studied at 1.0 T. Magnetic resonance imaging included cardiac-gated sagittal dual-echo CSE and a cardiac-gated fast STIR sequence. Images were scored regarding number, size, and location of focal lesions, diffuse abnormalities and presence/hindrance of artifacts by two experienced radiologists. Examinations were scored as being definitely normal, indeterminate, or definitely abnormal. Interobserver agreement regarding focal lesions was higher for CSE (ϰ = 0.67) than for fast STIR (ϰ = 0.57) but did not differ significantly. Of all focal lesions scored in consensus, 47 % were scored on both sequences, 31 % were only detected by fast STIR, and 22 % only by dual-echo CSE (n. s.). Interobserver agreement for diffuse abnormalities was lower with fast STIR (ϰ = 0.48) than dual-echo CSE (ϰ = 0.65; n. s.). After consensus, fast STIR showed in 10 patients diffuse abnormalities and dual-echo CSE in 3. After consensus, in 19 of 20 patients dual-echo CSE scans were considered as definitely abnormal compared with 17 for fast STIR. The fast STIR sequence is a useful adjunct to dual-echo CSE in detecting focal abnormalities and is helpful in detecting diffuse MS abnormalities in the spinal cord. Due to the frequent occurrence of artifacts and the lower observer concordance, fast STIR cannot be used alone.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1084
    Keywords: Key words: Mandible CT ; Mandible MRI ; Oral carcinoma imaging ; Mandible imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. In oral carcinomas close to the mandible, tumour invasion of the mandible is important in selecting segmental or marginal resection. Imaging may play a role in assessing tumour invasion. This study compares the accuracy of panoramic X-ray, CT and MR imaging in assessing invasion of the mandible in 29 patients. At histopathology, 6 patients had mandible erosion, 12 had invasion and 11 had an intact mandible. Magnetic resonance imaging had the highest sensitivity (94 %), but a low specificity (73 %), with 3 of 11 intact mandibles interpreted as positive. Furthermore, MR often overestimated the extent of tumour invasion. On the other hand, CT and panoramic X-ray had a lower sensitivity (64 and 63 %, respectively) and a higher specificity (89 and 90 %, respectively). Computed tomography (using 5-mm sections) and panoramic X-ray had a similar accuracy, and negative findings do not exclude invasion. Magnetic resonance imaging was the most sensitive technique but had more false positives and frequently overestimated the extent of tumour invasion. Because none of the radiological techniques are accurate enough, clinical examination seems at present to remain the most important modality in deciding between segmental and marginal resection. Tumour invasion at CT or panoramic X-ray is a strong argument for a segmental resection.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1084
    Keywords: Key words: Multiple sclerosis – Magnetic resonance imaging – Spinal imaging – Diagnosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. We examined the value of spinal cord magnetic resonance imaging (MRI) in the diagnostic work-up of multiple sclerosis (MS). Forty patients suspected of having MS were examined within 24 months after the start of symptoms. Disability was assessed, and symptoms were categorized as either brain or spinal cord. Work-up further included cerebrospinal fluid analysis and standard proton-density, T2-, and T1-weighted gadolinium-enhanced brain and spinal cord MRI. Patients were categorized as either clinically definite MS (n = 13), laboratory-supported definite MS (n = 14), or clinically probable MS (n = 4); four patients had clinically probable MS, and in nine MS was suspected. Spinal cord abnormalities were found in 35 of 40 patients (87.5 %), consisting of focal lesions in 31, only diffuse abnormalities in two, and both in two. Asymptomatic spinal cord lesions occurred in six patients. All patients with diffuse spinal cord abnormality had clear spinal cord symptoms and a primary progressive disease course. In clinically definite MS, the inclusion of spinal imaging increased the sensitivity of MRI to 100 %. Seven patients without a definite diagnosis had clinically isolated syndromes involving the spinal cord. Brain MRI was inconclusive, while all had focal spinal cord lesions which explained symptoms and ruled out other causes. Two other patients had atypical brain abnormalities suggesting ischemic/vascular disease. No spinal cord abnormalities were found, and during follow-up MS was ruled out. Spinal cord abnormalities are common in suspected MS, and may occur asymptomatic. Although diagnostic classification is seldom changed, spinal cord imaging increases diagnostic sensitivity of MRI in patients with suspected MS. In addition, patients with primary progressive MS may possibly be earlier diagnosed. Finally, differentiation with atypical lesions may be improved.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European radiology 6 (1996), S. 156-169 
    ISSN: 1432-1084
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract 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 assesing 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 contraindicated, CT may still be recommended. The radiologist's experience with CT or MRI also determines the choice between the two modalities.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1920
    Keywords: Key words Nerves ; cranial ; Nerve ; trigeminal ; Schwannoma ; Neurofibroma ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We reviewed the clinical and MRI findings in primary nerve-sheath tumours of the trigeminal nerve. We retrospectively reviewed the medical records, imaging and histological specimens of 10 patients with 11 primary tumours of the trigeminal nerve. We assessed whether tumour site, size, morphology or signal characteristics were related to symptoms and signs or histological findings. Histological proof was available for 8 of 11 tumours: six schwannomas and two plexiform neurofibromas. The other three tumours were thought to be schwannomas, because they were present in patients with neurofibromatosis type 2 and followed the course of the trigeminal nerve. Uncommon MRI appearances were observed in three schwannomas and included a large intratumoral haemorrhage, a mainly low-signal appearance on T2-weighted images and a rim-enhancing, multicystic appearance. Only four of nine schwannomas caused trigeminal nerve symptoms, including two with large cystic components, one haemorrhagic and one solid tumor. Of the five schwannomas which did not cause any trigeminal nerve symptoms, two were large. Only one of the plexiform neurofibromas caused trigeminal nerve symptoms. Additional neurological symptoms and signs, not related to the trigeminal nerve, could be attributed to the location of the tumour in three patients.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1434-4726
    Keywords: Head and neck cancer ; Cervical lymph node metastases ; Magnetic resonance imaging ; Ultrasound ; Aspiration cytology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Although palpation has proved to be an unreliable staging procedure, the indications for and the implications of more reliable radiologic staging methods for the neck in patients with a primary squamous cell carcinoma of the head and neck remain controversial. Only a very accurate imaging technique can replace neck dissection in clinical NO disease. This study compares the value of palpation with computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound (US) with or without guided aspiration cytology for neck node staging. One hundred and thirty-two patients with squamous cell carcinoma of the head and neck were examined radiologically before undergoing a total of 180 neck dissections as part of their treatment. CT, US and MRI proved to be significantly more accurate than palpation for cervical lymph node staging. The accuracy of US-guided aspiration cytology was significantly better than of any other technique used in this study. Modern imaging techniques are essential for appropriate assessment of neck node metastases. In view of advances in the accuracy of contemporary imaging, the need for elective treatment of the neck requires reappraisal.
    Type of Medium: Electronic Resource
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