Gadolinium-DTPA-Enhanced MR Imaging of Spinal Neoplasms: Preliminary Investigation and Comparison with Unenhanced Spin-Echo and STIR Sequences

Unenhanced T1- and T2-weighted spin-echo, short inversion time inversion recovery (STIR), and gadolinium-DTPA (Gd-DTPA)-enhanced spin-echo and STIR imaging techniques were used in 20 patients as part of a multicenter study to assess the safety and efficacy of Gd-DTPA in spinal imaging. Five patients had normal MR scans. Of those with lesions, both Gd-DTPA-enhanced T1-weighted spin-echo and unenhanced STIR scans improved detection and evaluation of spinal tumors over conventional spin-echo methods, particularly T2-weighted spin echo, by providing higher tissue contrast in shorter imaging times. The Gd-DTPA-enhanced T1-weighted spin-echo scans were most helpful in evaluating intradural tumors, whereas STIR sequences were most effective for extradural tumors and bone metastases. In most cases, Gd-DTPA-enhanced T1-weighted spin-echo scans best delineated tumor margins, and the enhancement was helpful in suggesting a cellular or active nature of the lesions. In some cases, the enhancement resulted in a more homogeneous and thus less abnormal-appearing marrow in vertebrae involved by tumor; therefore, a precontrast T1-weighted spin-echo scan is necessary in all patients who are to be studied with Gd-DTPA.A combined approach that uses T1-weighted spin-echo, Gd-DTPA-enhanced T1-weighted spin-echo, and STIR images currently appears optimal for MR imaging of spinal neoplasms. T2-weighted spin-echo images add information only in occasional cases.     

Magnetic resonance imaging for diagnosis and follow-up of genitourinary, pelvic, and perineal rhabdomyosarcoma.

Magnetic resonance (MR) imaging, ultrasound, and computed tomography (CT) were performed for diagnosis and follow-up of rhabdomyosarcoma (RMS) arising from the genitourinary tract in five children, pelvic musculature in one, and the perineum in three others. MR imaging performed at 1.0 T included the following: spin-density-, T1-, and T2-weighted images in all nine patients; gadopentatate dimeglumine (Gd-DTPA)-enhanced T1-weighted images in five; and short TI inversion recovery (STIR) images in two children. Longitudinal T1-weighted images were of additional help in localizing the primary tumor at diagnosis and detecting local spread. Residual or recurrent disease within the bladder was best detected by spin-density images. Gd-DTPA enhancement improved contrast in two studies, but paramagnetic artifacts obscured intravesical lesions in three other studies. STIR images disclosed pelvic and retroperitoneal lymphadenopathy. MR imaging is recommended as the key method of diagnosis and follow-up of pelvic RMS.     

Magnetic resonance imaging for diagnosis and follow-up of genitourinary,pelvic, and perineal rhabdomyosarcoma

Magnetic resonance (MR) imaging, ultrasound, and computed tomography (CT) were performed for diagnosis and follow-up of rhabdomyosarcoma (RMS) arising from the genitourinary tract in five children, pelvic musculature in one, and the perineum in three others. MR imaging performed at 1.0 T included the following: spin-density-, T1-, and T2-weighted images in all nine patients; gadopentatate dimeglumine (Gd-DTPA)-enhanced T1-weighted images in five; and short TI inversion recovery (STIR) images in two children. Longitudinal T1-weighted images were of additional help in localizing the primary tumor at diagnosis and detecting local spread. Residual or recurrent disease within the bladder was best detected by spin-density images. Gd-DTPA enhancement improved contrast in two studies, but paramagnetic artifacts obscured intravesical lesions in three other studies. STIR images disclosed pelvic and retroperitoneal lymphadenopathy. MR imaging is recommended as the key method of diagnosis and follow-up of pelvic RMS.     

Gd-DTPA-enhanced short repetition time and short inversion time inversion recovery magnetic resonance imaging. Experimental and clinical assessment

To suppress both water and fat signal while retaining the high signal of Gd-DTPA enhancement, magnetic resonance imaging (MRI) of phantoms and 28 patients with mass lesions was done using short repetition time (TR) and short inversion time inversion recovery (STIR) sequences. Optimal STIR pulse sequences of 500 to 1000/80-100/20-30 (TR/TI/TE) were determined by an experimental study. In most instances, a signal bandwidth of +/- 8 kHz was used to increase the signal-to-noise ratio. The authors measured image contrast between lesions and adjacent fatty tissue and compared postcontrast STIR and T1-weighted spin-echo (T1-W SE) images. When the signal intensity of a lesion is 80% of adjacent fatty tissue on postcontrast T1-W SE, short TR STIR images provide better tumor delineation.     

Gd-DTPA-enhanced MR imaging of the brain in patients with meningitis: comparison with CT

Plain and Gd-DTPA-enhanced MR images of the brain were obtained in 18 consecutive patients with meningitis (eight with tuberculous, five with bacterial, three with viral, and two with fungal infections); the MR images were compared with CT scans. MR images were obtained on a 2.0-T superconducting unit with both T1- and T2-weighted pulse sequences before injection and with a T1-weighted sequence after injection of Gd-DTPA (0.1 mmol/kg) in all patients. In tuberculous meningitis, MR imaging depicted ischemia/infarct, hemorrhagic infarct of basal ganglia, meningeal enhancement at either basal cistern or convexity surface of brain, and associated small granulomas in a few more patients than CT did. In bacterial meningitis, primary foci of extracranial inflammation (i.e., mastoid, paranasal sinuses) and adjacent intracranial lesions including localized dural inflammation, subdural fluid collection, and/or brain parenchymal lesions were demonstrated much better on MR than on CT. Otherwise, MR images generally matched the CT scan. Although the plain MR images, both T1- and T2-weighted, were the most sensitive in delineating ischemia/infarct, hemorrhage, and edema, they were not as specific as Gd-DTPA-enhanced T1-weighted images and postcontrast CT scans in defining the active inflammatory process of the meninges and focal lesions precisely. We conclude that if Gd-DTPA is used, MR imaging appears to be superior to CT in the evaluation of patients with suspected meningitis. Precontrast MR is needed to delineate ischemia/infarct, edema, and subacute hemorrhage.     

Gd-DTPA-enhanced MR imaging of the brain in patients with meningitis: comparison with CT

Plain and Gd-DTPA-enhanced MR images of the brain were obtained in 18 consecutive patients with meningitis (eight with tuberculous, five with bacterial, three with viral, and two with fungal infections); the MR images were compared with CT scans. MR images were obtained on a 2.0-T superconducting unit with both T1- and T2-weighted pulse sequences before injection and with a T1-weighted sequence after injection of Gd-DTPA (0.1 mmol/kg) in all patients. In tuberculous meningitis, MR imaging depicted ischemia/infarct, hemorrhagic infarct of basal ganglia, meningeal enhancement at either basal cistern or convexity surface of brain, and associated small granulomas in a few more patients than CT did. In bacterial meningitis, primary foci of extracranial inflammation (i.e., mastoid, paranasal sinuses) and adjacent intracranial lesions including localized dural inflammation, subdural fluid collection, and/or brain parenchymal lesions were demonstrated much better on MR than on CT. Otherwise, MR images generally matched the CT scan. Although the plain MR images, both T1- and T2-weighted, were the most sensitive in delineating ischemia/infarct, hemorrhage, and edema, they were not as specific as Gd-DTPA-enhanced T1-weighted images and postcontrast CT scans in defining the active inflammatory process of the meninges and focal lesions precisely. We conclude that if Gd-DTPA is used, MR imaging appears to be superior to CT in the evaluation of patients with suspected meningitis. Precontrast MR is needed to delineate ischemia/infarct, edema, and subacute hemorrhage.     

Gd-DTPA-enhanced MR imaging of spinal tumors

Forty-eight Gd-DTPA-enhanced MR examinations of the spine were performed in 40 patients referred for MR because of clinically suspected spinal tumor or for further evaluation of an expanded cord. The study group consisted of 32 patients with spinal tumors (seven ependymomas; seven astrocytomas; four hemangioblastomas; two arteriovenous malformations; two unidentified intramedullary neoplasms; four meningiomas; and single cases of metastatic breast carcinoma, cavernous hemangioma with associated hematomyelia, neurinoma, angiolipoma, drop metastasis from medulloblastoma, and epidermoid with diastematomyelia). In the remaining eight patients, other diagnoses were established: thoracic disk herniation (two patients), lumbosacral meningocele (one), syringomyelia secondary to arachnoiditis (four), and expanded cord secondary to gliotic tissue (one). All but two diagnoses were proved histologically by biopsy, surgery, or autopsy; in the two patients with arteriovenous malformations, the definitive diagnosis was made by spinal angiography. Contrast enhancement occurred in 30 of the 32 spinal tumors, and Gd-DTPA-enhanced T1-weighted images proved helpful in defining and outlining intra- and extramedullary spinal neoplasms. All ependymomas and astrocytomas (including low-grade astrocytomas) enhanced. In meningiomas, an immediate and uniform contrast uptake was demonstrated. Additional advantages of Gd-DTPA MR include the differentiation of solid tumor components vs syrinx or cyst or pseudotumoral areas of cord expansion, and the differentiation of residual or recurrent tumor from scar tissue in postoperative patients. Our results suggest that IV-injected Gd-DTPA improves MR sensitivity and specificity in the evaluation of spinal lesions.     

Gd-DTPA-enhanced cranial MR imaging in children: initial clinical experience and recommendations for its use

Gd-DTPA was administered prospectively to 65 consecutive children (ages 1 day to 18 years, mean 9.6 years) to document its utility and safety for routine cranial MR imaging. Precontrast T1- and T2-weighted scans and postcontrast T1-weighted scans were obtained. No complications or significant adverse reactions were encountered. Contrast enhancement was seen in 14 lesions from seven patients, but each of these patients had some abnormality also present on precontrast images. Contrast enhancement was thought to be extremely helpful in characterizing four primary tumors and moderately helpful in characterizing four other lesions. Absence of contrast enhancement was helpful in clarifying the nature of abnormalities seen in an additional four patients. Gd-DTPA may be used safely in children, but this study does not support its routine administration. The highest incremental diagnostic yield from its use will likely be among patients with suspected neoplasms or inflammatory diseases and among those requiring further characterization of lesions seen on precontrast scans.     

Tumors of the nasopharynx and adjacent areas: MR imaging with Gd-DTPA

The purpose of this study was to describe our experience with Gd-DTPA-enhanced MR imaging in the evaluation of the most common nasopharyngeal tumors. Forty-two patients with tumors of the nasopharynx and adjacent spaces had MR imaging before and after IV injection of Gd-DTPA. Images were obtained with a 1.0-T superconducting magnet imaging system in transverse, coronal, and sagittal planes with T1- and T2-weighted sequences. MR images were compared with CT scans and tumor histology. The studies were categorized by using a grading system with grades ranging from unsatisfactory (grade 0) to optimal (grade 3). Contrast-enhanced MR enables better identification of small anatomic details such as both palatini muscles and the pharyngobasilar fascia. MR after Gd-DTPA was superior to CT in all cases except for tumors of the maxillary sinuses. MR with Gd-DTPA is recommended for tumors that are small and difficult to detect on the initial nonenhanced MR examination or that show subtle infiltrations. Because of the increased cost and longer examination time, MR with Gd-DTPA does not need to be done when large tumors are well delineated.     

Tumors of the nasopharynx and adjacent areas: MR imaging with Gd-DTPA

The purpose of this study was to describe our experience with Gd-DTPA-enhanced MR imaging in the evaluation of the most common nasopharyngeal tumors. Forty-two patients with tumors of the nasopharynx and adjacent spaces had MR imaging before and after IV injection of Gd-DTPA. Images were obtained with a 1.0-T superconducting magnet imaging system in transverse, coronal, and sagittal planes with T1- and T2-weighted sequences. MR images were compared with CT scans and tumor histology. The studies were categorized by using a grading system with grades ranging from unsatisfactory (grade 0) to optimal (grade 3). Contrast-enhanced MR enables better identification of small anatomic details such as both palatini muscles and the pharyngobasilar fascia. MR after Gd-DTPA was superior to CT in all cases except for tumors of the maxillary sinuses. MR with Gd-DTPA is recommended for tumors that are small and difficult to detect on the initial nonenhanced MR examination or that show subtle infiltrations. Because of the increased cost and longer examination time, MR with Gd-DTPA does not need to be done when large tumors are well delineated.     

Gd-DTPA-enhanced MR imaging in pediatric patients after brain tumor resection

A prospective study was conducted in 15 pediatric patients who had undergone resection of intracranial tumors. The object of the study was to determine the safety and efficacy of magnetic resonance (MR) imaging performed after the administration of gadolinium diethylenetriamine-pentaacetic acid (Gd-DTPA) in evaluating residual or recurrent tumor. Precontrast T1-weighted, intermediate, and T2-weighted images were obtained at a field strength of 1.5 T. Gd-DTPA was then injected intravenously in a dose of 0.1 mmol per kilogram of body weight. T1-weighted images were obtained within 5 minutes after the injection, intermediate and T2-weighted images were obtained 10 minutes after the injection, and T1-weighted images were obtained approximately 20 minutes after the injection. None of the patients experienced allergic reactions or other side effects. Physical examination findings and laboratory values were unchanged after the Gd-DTPA-enhanced examination. In six patients, contrast-enhanced images depicted tumor not suspected on nonenhanced images. In four other patients, enhanced images provided better definition of the tumor core. The images of one patient with a brain stem tumor showed no evidence of enhancement. Pre- and postcontrast images of three previously treated patients showed no evidence of tumor. Gd-DTPA appears to be a safe and effective contrast agent for MR imaging and provides a more accurate method of imaging in the follow-up of brain tumors in pediatric patients.     

MR imaging of bone metastasis]

One hundred and three patients with known malignancy and suspected bone metastasis underwent magnetic resonance imaging. In 93%, the metastatic lesions, detected both on plain films and radionuclide bone scans, showed decreased signal intensity on T1-weighted images and increased signal intensity on T2-weighted images. All lesions, except one lesion showing much blastic change on plain films, showed contrast enhancement with Gd-DTPA administration. Although further investigation is needed, a correlation between the type of primary malignancy and the signal intensity of the metastatic lesion is suggested. Among 312 metastatic lesions detected by MR imaging, 272 lesions (87%) and 134 lesions (40%) were also detected by radionuclide bone scans and plain films, respectively. In five cases, MR imaging clearly revealed the lesion compressing the spinal cord, which helped us formulate a therapeutic plan. We conclude that MR imaging is the most sensitive examination for detecting bone metastasis and is necessary for planning treatment.     

Comparison of multi echo and contrast-enhanced MR scans: Image contrast and delineation of intracranial tumors

Summary In 56 patients with intracranial tumor T2-weighted multi echo (ME) [TR: 1600 ms, TE: 30 to 240 ms (8 echoes)] and T1-weighted Gd-DTPA-enhanced images (TR: 400 ms, TE: 30 ms or 35 ms) were compared with respect to tumor contrast and tumor delineation. In subgroups of 20 and 14 patients, respectively, tumor/brain-and tumor/edemacontrast were assessed on both a subjective and a quantitative basis (contrast-to-noise ratio, CNR). CNR's for tumor/brain-contrast were significantly higher on Gd-DTPA enhanced images than on ME scans. No significant differences between techniques were found for CNR's of tumor/edema-contrast. ME images yielded pathological findings in 54 of the 56 patients but visually assessed tumor delineation was achieved in only 36 cases. Fifteen out of 25 intraaxial tumors and 5 out of 31 extraaxial tumors could not be sufficiently delineated on ME images. In contrast, Gd-DTPA-enhanced images provided differentiation of tumor and surrounding tissues in 55 of 56 studies. In conclusion, ME images have proved highly sensitive in detecting intracranial lesions. However, brain tumors, especially intraaxial tumors could often not be differentiated from adjacent tissues on ME images. After Gd-DTPA, T1-weighted images provided more reliable tumor detection and delineation.This work was supported by grant 01 VF 142, Bundesministerium für Forschung und Technologie, Bonn     

Gadolinium-enhanced magnetic resonance imaging of spinal tumours

The use of gadolinium diethylenetriamine-penta-acetic acid (Gd-DTPA) (Magnevist) enhanced magnetic resonance imaging (0.15 T) in the assessment of spinal tumours is described. Thirty-five patients were entered into the study and a total of 39 examinations were performed. The information obtained from unenhanced T1- and T2-weighted spin-echo sequences was compared with the Gd-DTPA-enhanced T1 images. Thirty patients had intradural lesions and five had extradural lesions. A variable pattern of enhancement of intramedullary tumours was found, which in part reflected differences in the cystic component of the lesions. Extramedullary intra- and extradural lesions generally showed marked enhancement. The greatest contribution to management decisions was in the evaluation of intramedullary tumours where the use of contrast enhancement facilitated the precise localization of active tumour, differentiation of cystic and solid components of tumour, separation of tumour from peritumoral oedema and, in cases of suspected recurrence, aided distinction between tumour and both post-operative scarring and radiation damage.     

Extracranial lesions of the head and neck: preliminary experience with Gd-DTPA-enhanced MR imaging

The authors report initial experience with magnetic resonance imaging enhanced with gadolinium diethylenetriaminepentaacetic acid (DTPA) in 27 patients with various extracranial lesions of the head and neck. Unenhanced T1- and T2-weighted images were compared with T1-weighted images obtained 3-30 minutes after Gd-DTPA administration. Overall, compared with precontrast T1- and T2-weighted images, Gd-DTPA improved the visibility of lesions in 11 and five of 27 patients, respectively. Gd-DTPA particularly improved the conspicuity of tumors of the nasal cavity and paranasal sinuses and tumors having perineural or intracranial extension. Gd-DTPA-enhanced images were equivalent to precontrast T1- and T2-weighted images in five and 13 patients, respectively, and inferior to them in nine and eight patients, respectively. Mixed results were obtained in two patients and one patient when Gd-DTPA-enhanced images were compared with T1- and T2-weighted images, respectively. The authors conclude that Gd-DTPA has definite but limited uses in extracranial head and neck pathologic conditions and that more research is needed to evaluate particular applications.     

Atypical appearance of elastofibroma dorsi on MRI: case reports and review of the literature

Three patients with histologically proven elastofibroma dorsi underwent MRI, using T1-weighted, T2-weighted, STIR (short inversion time inversion recovery), and contrast-enhanced SE sequences. All lesions typically displayed low signal intensity masses interspersed with areas of high signal intensity on T1- and T2-weighted SE images. Contrary to prior reports, two patients showed marked enhancement of the mass after administration of Gd-DTPA. Although the characteristic signal intensity on conventional T1- and T2-weighted images may lead to the early diagnosis of this rare tumor, radiologists should be aware that marked contrast enhancement may be representative in elastofibroma dorsi.     

Visceral metastases from melanoma: findings on MR imaging.

Typical ocular and CNS melanomas are hyperintense on T1-weighted MR images and hypointense on T2-weighted MR images. We performed MR imaging in 48 patients with melanoma metastatic to visceral organs. Images were reviewed retrospectively in order to determine whether there were predominant MR features specific for visceral melanoma and to see if visceral metastases have MR characteristics similar to metastases in the CNS. Eleven patients also were examined after injection of gadopentetate dimeglumine to evaluate the enhancement characteristics of these tumors. Two hundred sixty-one lesions were found. Lesions were classified according to their signal intensities relative to uninvolved liver on T1-weighted, T2-weighted, and short TI inversion recovery (STIR) pulse sequences. Most commonly, lesions were either hypointense or isointense on T1-weighted sequences and hyperintense on T2-weighted and STIR sequences (185 lesions). Less frequently, lesions were hyperintense on T1-weighted sequences and hypointense or isointense on T2-weighted and STIR sequences (59 lesions). A mixed pattern was seen on T1- and T2-weighted sequences in 17 lesions. The patterns did not correlate with lesion size. Of the three sequences studied by subjective comparison, the STIR sequence in our series had the highest sensitivity for lesion detection and yielded the highest lesion conspicuity. Injection of gadopentetate dimeglumine in 11 patients did not increase either the number or the conspicuity of lesions seen. Our results show that visceral metastases from melanoma have a wide variety of appearances on MR images. The STIR sequence appears to be optimal, and the metastases do not enhance with gadopentetate dimeglumine.     

Gadolinium-DTPA in MR imaging of glioblastomas and intracranial metastases

In 14 patients with the diagnosis of glioblastoma (n = 7) or intracranial metastases (n = 7), magnetic resonance (MR) imaging was performed using a variety of spin-echo (SE) pulse sequences before and after intravenous injection of 0.1 mmol gadolinium-DTPA (Gd-DTPA) per kilogram of body weight. In 10 patients, tumor tissue could not be adequately differentiated from perifocal edema on unenhanced scans with any of the applied pulse sequences. In four cases of intracranial metastases, poor differentiation between tumor and perifocal edema was possible in T2-weighted (SE 1600/70 and SE 1600/105) unenhanced scans. After administration of Gd-DTPA, tumor tissue showed marked contrast enhancement, and tumor delineation was consistently possible on SE 800/35 images. Tumor tissue could be differentiated from perifocal edema on SE 800/70 scans. Gd-DTPA is likely to increase the potential of MR imaging and refine the evaluation of glioblastomas and intracerebral metastases.     

MR evaluation of the parotid gland using STIR and Gadolinium-enhanced imaging

The purpose of this study was to determine the efficiency of the STIR sequence in teh pre-operative assessment of salivary gland lesions, and to evaluate whether administration of intravenous contrast medium provided any additonal information. Nineteen patients with presumed parotid lesions were imaged using T₁-weighted soin-echo and STIR sequences and nine patients also had Gadolinium-DTPA (Gd-DTPA) enhancement. The pathological nature of all lesions was confirmed by cytological or histological examination. T₁-weighted spin-echo images were most useful for visualising anatomical structures and identifying the course of the facial nerve. Internal strcuture of tumours was best displayed with gladolinium enhanced images. Margination and conspicuity of lesions was optimal with STIR, which also achieved a minimal resolution of lesions of 4 × 6 mm diameter. Gd-DTPA enhancement of small lesions was sometimes misleading as they became obscured by surrounding enhancing glandular tissue or overlying fat. It is concluded that the combination is adequate to display anatomy and pathology with accuracy in both extensive ans subtle salivary gland disease. Gd-DTPA did not add to the diagnostic information already obtained by T1 and STIR imaging despite clearer demonstration of tumour architecture. Correspondence to: R. Chaudhuri     

Acoustic neuromas: Gd-DTPA enhancement in MR imaging

Magnetic resonance (MR) imaging examinations were performed in ten patients with 12 acoustic neuromas before and after intravenous administration of 0.1 mmol/kg body weight gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). The degree of enhancement was greatest with the inversion recovery sequence 1,500/500/44 (repetition time [TR]/inversion time/echo delay time [TE]), followed by spin-echo (SE) 544/44 (TR/TE) sequences, then by SE 1,500/44 and SE 1,500/80 sequences. After enhancement there was a 50% reduction for measured T1 values, 33% for T2, and no significant change for proton density. There were no toxic effects on patients. Enhanced CT scans failed to demonstrate lesions in six of 12 cases. Air-CT technique improved sensitivity in four of five cases. Enhanced MR imaging added significant clinical information in two small intracanalicular tumors and in one recurrent tumor.