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 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This article is a review of computed tomography (CT) and magnetic resonance imaging (MRI) findings in three groups of pathological conditions of the globe: a) malignant tumors, b) benign tumors and vascular lesions, and c) miscellaneous conditions. MRI technical refinements and the use of gadolinium-DTPA as an enhancement agent provide better anatomic definition of the globe. However, CT remains the method of choice in the investigation of lesions with calcification and bone. In the group of malignant tumors, retinoblastoma, the most common intraocular tumor in childhood, is best diagnosed with CT; for malignant melanoma, the most frequently encountered primary intraocular malignancy in adults, MR is the imaging modality of choice; and for metastatic tumors to the eye, mainly carcinomas, CT and MRI do not show characteristic features.
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PMID:Evaluation of the globe using computed tomography and magnetic resonance imaging. 159 81

Computed tomography (CT) and magnetic resonance imaging (MRI) assessment of internal auditory canal lesions focuses on acoustic neurinomas (Schwannomas), a small percentage of which are entirely intracanalicular. MR is now the imaging method of choice and allows for the detection of intracanalicular tumors as small as 3 mm. Acoustic neurinomas are isointense relative to the pons on MR T1-weighted images, mildly hyperintense on MR T2-weighted images, and enhance intensely after i.v. administration of gadolinium-DTPA. The radiologic evaluation of the cerebellopontine angle first addresses lesions of the angle itself, other than acoustic neurinomas. On CT, meningiomas show calcifications in 25% of cases and homogeneous enhancement in 90%; on MR they demonstrate homogeneous gadolinium-DTPA enhancement. Epidermoids do not enhance on MR. Cholesterol granulomas are strongly hyperintense on MR T1- and T2-weighted images. Rare vascular lesions may mimic neoplasm in the posterior fossa and in the cerebellopontine angle: vertebral basilar dolichoectasia, vascular loop or aneurysm of the anterior inferior cerebellar artery. CT and MR characteristics of lesions extending into the cerebellopontine angle cistern are then reviewed: nonacoustic posterior fossa schwannomas, which have the same MR signal characteristics as the acoustic schwannoma; jugular fossa lesions, the most often encountered being the glomus jugular tumor; and rare intraxial posterior fossa tumors that extend into the cerebellopontine angle.
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PMID:Magnetic resonance imaging and computed tomography of the internal auditory canal and cerebellopontine angle. 159 84

The methodology for evaluation of the facial nerve (CT and MR technique) is presented and the need for routine use of gadolinium-DTPA with MRI is emphasized. The various disorders causing facial palsy with their clinical and radiological features are described. Although tumors only cause 6% of facial nerve disorders, they require a thorough radiologic workup. Schwannoma is the most common neoplasm arising from the facial nerve and can occur anywhere along the nerve course: cerebellopontine angle and internal auditory canal, geniculate ganglion, or tympanic, mastoid and intraparotid segments.
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PMID:Radiological evaluation of the facial nerve. 159 86

Neurofibromatosis of the genitourinary system is rare. We present the CT and MR findings of neurofibromas of the bladder in three patients with von Recklinghausen disease (neurofibromatosis, Type 1). In one case, genitourinary involvement was the primary presentation of the disease. Both CT and MR imaging revealed diffuse and nodular bladder wall involvement, along with pelvic sidewall and adjacent soft tissue abnormalities. The CT attenuation coefficients measured near soft tissue density. On T1-weighted spin echo MR images the tumors revealed signal intensity slightly greater than that of skeletal muscle. Neurofibromas showed markedly increased signal intensity on T2-weighted images relative to the surrounding soft tissues, with marked enhancement in two cases imaged following Gd-DTPA administration. Obstructive hydronephrosis was present in all cases, presumably due to neurofibromas involving the trigonal region. Pelvic sidewall tumors were visualized as rounded, nodular masses extending into the obturator foramina. In the evaluation of patients with von Recklinghausen disease, MR imaging, compared with CT, more clearly defined tumor extent within the bladder, pelvic sidewalls, and surrounding soft tissues.
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PMID:CT and MR of neurofibromatosis of the bladder. 159 28

The new hepatobiliary contrast agent Mangan-DPDP, unlike extracellular Gd-DTPA, leads to a constant increase in signal intensity of normal liver tissue in MR imaging of the liver which lasts at least for 30 minutes. In 19 patients with malignant liver tumors there was no difference in the contrast between tumor and liver when using a dose of 5 or 10 mumol/kg. Contrast enhanced T1-w SE- and T1-w GE sequences show a significant increase in tumor/liver contrast compared with T1-weighted unenhanced sequences. This increase was also significant when compared with T2-w SE sequences. In 16% additional focal lesions were detected on the enhanced scan.
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PMID:[Manganese-DPDP in the MR tomography of malignant liver tumors. The initial results with a new hepatobiliary contrast agent]. 159 50

A 62-year-old woman was admitted complaining of clumsiness in both hands. On neurological examination, bilateral hand muscles were weak, both legs were spastic and hyperreflexic, all the extremities were hypoesthetic. Urological examination revealed detruser sphincter dyssynergia. Spinal CT scan demonstrated an iso density mass lesion in the cervical spinal cord, and it was markedly enhanced. On MRI, it was also markedly enhanced by Gd-DTPA. The operative finding was that an oval shaped tumor was buried in the spinal cord and was totally removed. Its histological diagnosis was neurofibroma. Intramedullary neurofibroma is rare and only 18 cases have been reported. In this case the tumor seemed to have arisen at the root entry zone and to have grown sub-pially.
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PMID:[Intramedullary neurofibroma in the cervical spinal cord; a case report]. 159 36

We retrospectively reviewed the findings in 655 consecutive young patients who underwent contrast-enhanced MR examinations (1.5T) of the head or spine. Their ages ranged from 4 months to 20 years (mean 10 years). There was a 1.7% incidence of minor adverse reactions to gadolinium (Gd)-DTPA, none of which required treatment; no serious adverse reactions were encountered. Based on the radiologic diagnosis the patients were divided into three groups: (1) normal, (2) CNS neoplasm, (3) abnormal but not neoplasm. There were 178 patients thought to have CNS neoplasms and of these 156 (88%) enhanced. Of 124 histologically confirmed neoplasms 115 (93%) showed enhancement after Gd-DTPA. Eight children had histologically confirmed spinal neoplasms; 5 of 6 neurofibromas and 2 ependymomas enhanced. In the 216 patients with abnormalities thought not to be neoplastic, the enhancement rate was 11%; most of the enhancing lesions were vascular malformations. There were very few examples of inflammatory disease, acute trauma or stroke among our patients.
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PMID:Diagnostic role of gadolinium-DTPA in pediatric neuroradiology. A retrospective review of 655 cases. 160 9

Gadolinium (4S)-4-(4-ethoxybenzyl)-3,6,9-tris(carboxylatomethyl)-3,6,9- triazaundecandioic acid-disodium salt (EOB-DTPA) ethoxybenzyl is a new hepatobiliary magnetic resonance (MR) contrast agent with dual elimination: 75% through the liver and bile and 25% through the kidneys in normal rats. In this study, Gd-EOB-DTPA was evaluated in a rodent model of metastatic liver disease to measure both relative enhancement and lesion-to-liver contrast. A secondary goal was to compare the relative performance of spin-echo (SE) and short inversion time inversion-recovery (STIR) imaging to demonstrate enhancement with Gd-EOB-DTPA. After administration of 0.1 mmol of Gd-EOB-DTPA per kilogram, liver signal increased (positive enhancement) more than 200% with the use of the SE technique and declined (negative enhancement) by more than 80% with use of the STIR technique. Only minimal enhancement of implanted liver tumor was observed. Unlike the tumor, the gall-bladder and lumen of the duodenum were progressively enhanced over time. The lesion-to-liver contrast increased by approximately 500% with both the SE and STIR techniques after administration of Gd-EOB-DTPA.
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PMID:Hepatobiliary enhancement with Gd-EOB-DTPA: comparison of spin-echo and STIR imaging for detection of experimental liver metastases. 160 81

The value of T1-weighted sequences after intravenous administration of Gd-DTPA and of T2-weighted sequences was compared in 43 patients suspected of having scrotal abnormalities. T2-weighted sequences gave better demonstration of the tunica albuginea and better contrast between tumor and parenchyma. The two techniques were equally sensitive for demonstrating testicular tumors but orchitis was better demonstrated on the contrast enhanced sequences. Motion artifacts were less marked in the T1-weighted sequences with contrast enhancement. In selected cases, contrast enhancement may be a valuable addition to native protocols. Our experience has indicated that MRI provides specific findings in cases of orchitis which are clinically atypical; this facilitates the decision to conservative treatment and prevents unnecessary exploration of the testes.
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PMID:[MR tomography in testicular processes. The significance of Gd-DTPA enhanced sequences in comparison with plain T2-weighted sequences]. 161 72

The accuracy of transrectal US (TRUS) and of MRI was evaluated in the preoperative staging and in local recurrences of rectal cancers. Fifty-four patients were examined: 45, with known rectal cancer, for preoperative staging, and 9 for the evaluation of local recurrences. Nineteen patients were examined with MRI in basal conditions, 21 after rectal air enema and 5 after paramagnetic contrast enema (Gd-DTPA). The following parameters were evaluated for preoperative staging: wall infiltration, invasion of perirectal fat and adjacent structures, lymph node involvement. Morphologic and signal intensity (on MRI) changes were evaluated for the diagnosis of local recurrences. TRUS provided 2 false positives. In the same patients, basal MRI results were poor, owing to difficult demonstration of the different wall layers, while in the patients studied after air enema, the lesion was hyperintense. In 20 patients with a fat-infiltrating tumor, TRUS provided 3 false negatives and 2 false positives; basal MRI yielded poor results, while air enema and paramagnetic contrast enema clearly demonstrated all fat-infiltrating lesions, with only one false positive.
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PMID:[Preoperative staging and recurrence of rectal tumors. Comparison of transrectal ultrasonography and magnetic resonance]. 163 40


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