Magnetic Resonance Imaging in degenerative disease of the lumbar spine: Fat Saturation technique and contrast medium.

PURPOSE: To examine both anterior and posterior elements of the lumbar spine in patients with low back pain using MRI T2-weighted sequences with Fat Saturation (FS) and contrast enhanced T1-weighted sequences with FS. MATERIALS AND METHODS: Two thousand eight hundred and twenty (2820) patients (1628 male, 1192 female, mean age 54) presenting low back pain underwent MRI standard examination (Sagittal T1w TSE and T2w TSE, axial T1 SE) with the addition of sagittal and axial T2w Fat Sat (FS) sequences. Among all the patients, 987 (35%) have been studied adding Contrast Enhanced (CE) T1w FS sequences after administration of contrast medium. RESULTS: Among 987 patients studied with contrast medium, we found: active-inflammatory intervertebral osteochondrosis in 646 (65%) patients; degenerative-inflammatory changes in facet joints (facet joint effusion, synovitis, synovial cysts) in 462 (47%); spondylolysis in 69 (7%); degenerative-inflammatory changes of the flava, interspinous and supraspinous ligaments in 245 (25%); inflammatory changes of posterior perispinal muscles in 84 (8%) patients. CONCLUSIONS: In patients with suspected no-disc-related low back pain, the implementation of T2w FS and CE T1w FS sequences to the standard MR protocol could allow a better identification of degenerative-inflammatory changes more likely associated to the pain.

Upright, weight-bearing, dynamic-kinetic MRI of the spine: initial results.

The potential relative beneficial aspects of upright, weight-bearing (pMRI), dynamic-kinetic (kMRI) spinal imaging over that of recumbent MRI (rMRI) include the revelation of occult spinal disease dependent on true axial loading, the unmasking of kinetic-dependent spinal disease and the ability to scan the patient in the position of clinically relevant signs and symptoms. This imaging unit under study also demonstrated low claustrophobic potential and yielded comparatively high resolution images with little motion/magnetic susceptibility/chemical shift artifact. Overall, it was found that rMRI underestimated the presence and maximum degree of gravity-dependent spinal pathology and missed altogether pathology of a dynamic nature, factors that are optimally revealed with p/kMRI. Furthermore, p/kMRI enabled optimal linkage of the patient's clinical syndrome with the medical imaging abnormality responsible for the clinical presentation, thereby allowing for the first time an improvement at once in both imaging sensitivity and specificity.

Merosin-deficient congenital muscular dystrophy (CMD): a study of 25 Brazilian patients using MRI.

BACKGROUND: Merosin-deficient congenital muscular dystrophy (CMD) is characterized clinically by hypotonia and muscular weakness and, on imaging studies, by white matter (WM) abnormality. OBJECTIVE: To evaluate MRI findings in Brazilian patients with merosin-deficient CMD. MATERIALS AND METHODS: Twenty-five patients were evaluated using MRI. Three patients presented with partial merosin deficiency and 22 with total merosin deficiency. Follow-up examinations were done in 7 cases. T1- and T2-weighted images were performed in all examinations, and fluid-attenuated inversion recovery (FLAIR) was performed in 15. Enhanced images were done in 11 cases. The WM involvement was classified according to location and severity. RESULTS: From 1991 to 2004, 32 MRI examinations were performed. Severe involvement was found in 23 patients in the frontal and temporal lobes, in 18 patients in the parietal lobes, and in 7 patients in the occipital lobes. The brain stem (n=5), cerebellum (n=6), internal capsules (n=1), and external capsules (n=5) were also affected. One patient had occipital pachygyria, and one had cerebellar vermian hypoplasia. No gadolinium enhancement was noted. Follow-up MRI showed no interval change (n=4), progression (n=1), or improvement of the findings (n=2). CONCLUSION: This series of patients demonstrated that there was no correlation between the extent of WM abnormality on MRI and the clinical status and degree of merosin deficiency (partial or total). Bilateral WM involvement was seen to be more prominent in the parietal, frontal, and temporal regions of the brain. The brain stem and internal and external capsules were less affected. Cerebellar WM involvement is rare. Changes on follow-up imaging studies did not correlate with the clinical status of the patient.

Giant tumefactive perivascular spaces.

BACKGROUND AND PURPOSE: The brain perivascular spaces (PVSs) are pial-lined, interstitial fluid-filled structures that accompany penetrating arteries. When enlarged, they may cause mass effect and can be mistaken for more ominous pathologic processes. The purpose of this study was to delineate the broad clinical and imaging spectrum of this unusual condition. METHODS: Thirty-seven cases of giant PVSs were identified from 1988 to 2004 and were retrospectively reviewed. Clinical data collected included patient demographics, presenting symptoms, and follow-up. Histopathologic data were reviewed when available. Images were evaluated for size and location of the giant PVSs, associated mass effect, hydrocephalus, adjacent white matter changes, and contrast enhancement. RESULTS: There were 24 men and 13 women with an age range of 6-86 years, (mean 46 years). The most common presenting feature was headache (15 patients). Thirty-two cases had multilocular clusters of variably sized cysts. Five lesions were unilocular. All lesions had signal intensity comparable to CSF and did not enhance. The most common location for the giant PVSs was the mesencephalothalamic region (21/36). Fourteen were located in the cerebral white matter; two were in the dentate nuclei. Nine giant mesencephalothalamic PVSs had associated hydrocephalus, which required surgical intervention. CONCLUSION: Giant tumefactive PVSs most often appear as clusters of variably sized cysts that are isointense relative to CSF and do not enhance. They are most common in the mesencephalothalamic region and may cause hydrocephalus. Although they may have striking mass effect, giant PVSs should not be mistaken for neoplasm or other diseases.

Intrathecal gadolinium (gadopentetate dimeglumine)-enhanced MR cisternography used to determine potential communication between the cerebrospinal fluid pathways and intracranial arachnoid cysts.

This study was designed to assess the feasibility of intrathecal gadolinium-enhanced magnetic resonance cisternography (MRC) for the evaluation of the presence or absence of communication of cranial arachnoid cysts with the cerebrospinal fluid (CSF) pathways of the central nervous system (CNS). This prospective study included 20 patients (12 males and 8 females) with a mean age of 37 years, who had, as a group, 22 intracranial arachnoid cysts identified on prior CT and/or MR examinations. Routine pre-contrast cranial MR imaging was followed by the intrathecal administration of 0.5 cc gadopentetate dimeglumine (GD) (Magnevist, Schering, Germany). Immediate and delayed (24 h) MR cisternography was then carried out. Eleven of 22 arachnoid cysts showed immediate CSF communication by the demonstration GD-contrast enhancement of the cyst fluid on the immediate post-injection scan. Contrast enhancement of the cyst was observed only on delayed MRC in six patients. MR imaging in five patients demonstrated no contrast enhancement of the arachnoid cysts on either immediate or delayed imaging. Six patients had mild transient post-procedure headache that was relieved by oral analgesics within 24 h. No serious immediate or chronic adverse effects or complications relating to the intrathecal contrast administration were observed. This study showed the relative safety, feasibility and reliability of low-dose intrathecal GD MR imaging in the demonstration of the communication or non-communication of intracranial arachnoid cysts with the CSF pathways of the CNS. In the future, this may have bearing on the selection for surgery of patients with intracranial arachnoid cysts presenting with clinical signs and symptoms potentially related to the location and mass effect of the cyst.

Acquired degenerative changes of the intervertebral segments at and suprajacent to the lumbosacral junction. A radioanatomic analysis of the nondiscal structures of the spinal column and perispinal soft tissues.

A review of the imaging features of normal and degenerative anatomy of the spine on medical imaging studies shows features that have been largely overlooked or poorly understood by the imaging community in recent years. The imaging methods reviewed included computed tomography (CT) with multiplanar reconstructions and magnetic resonance imaging (MRI). A routine part of the MRI examination included fat-suppressed T2 weighted fast-spin- or turbo-spin-echo acquisitions. As compared to the normal features in asymptomatic volunteers, alterations in the observed CT/MRI morphology and MR signal characteristics were sought in symptomatic individuals. Findings in symptomatic subjects which departed from the normal anatomic features of the posterior spinal elements in asymptomatic volunteers included: rupture of the interspinous ligament(s), neoarthrosis of the interspinous space with perispinous cyst formation, posterior spinal facet (zygapophyseal joint) arthrosis, related central spinal canal, lateral recess (subarticular zone) and neural foramen stenosis, posterior element alterations associated with various forms of spondylolisthesis, and perispinal muscle rupture/degeneration. These findings indicate that the posterior elements are major locations of degenerative spinal and perispinal disease that may accompany or even precede degenerative disc disease. Although not as yet proven as a reliable source of patient signs and symptoms in all individuals, because these observations may be seen in patients with radicular, referred and/or local low back pain, they should be considered in the evaluation of the symptomatic patient presenting with a clinical lumbosacral syndrome. Imaging recommendations, in addition to the usual close scrutiny of these posterior spinal elements and perispinal soft tissues on CT and MRI, include the acquisition of high-resolution multiplanar CT reconstructions, and fat-suppressed T2 weighted fast-spin- or turbo-spin-echo sequence MRI in at least one plane in every examination of the lumbar spine.

Proceedings of the State-of-the-Art Symposium on Diagnostic and Interventional Radiology of the Spine, Antwerp, September 7, 2002 (Part two). Upright, weight-bearing, dynamic-kinetic MRI of the spine: pMRI/kMRI.

PURPOSE: To review the general clinical utility of the first dedicated magnetic resonance imaging (MRI) unit enabling upright, weight-bearing positional evaluation of the spinal column (pMRI) during various dynamic-kinetic maneuvers (kMRI) in patients with degenerative conditions of the spine. MATERIALS & METHODS: This study consisted of a prospective non-statistical analysis of cervical or lumbar imaging examinations. All studies were performed on a recently introduced whole body MRI system (Stand-Up MRI, Fonar Corp, Melville, NY). The system operates at 0.6T using an electromagnet with a horizontal field, transverse to the longitudinal axis of the patient's body. Depending upon spinal level, all examinations were acquired with either a cervical or lumbar solenoidal radiofrequency receiver coil. This unit was configured with a top-front open design, incorporating a patient-scanning table with tilt, translation and elevation functions. The unique motorized patient handling system developed for the scanner allowed for vertical (upright, weight bearing) and horizontal (recumbent) positioning of all patients. The top-open construction also allowed dynamic-kinetic flexion and extension maneuvers of the spine. Patterns of bony and soft tissue change occurring among recumbent (rMRI) and upright neutral positions (pMRI), and dynamic-kinetic acquisitions (kMRI) were sought. RESULTS: Depending on the specific underlying pathologic degenerative condition, significant alterations observed on pMRI and kMRI that were either more or less pronounced than on rMRI included: fluctuating anterior and posterior disc herniations, hypermobile spinal instability, central spinal canal and spinal neural foramen stenosis and general sagittal spinal contour changes. No patient suffered from feelings of claustrophobia that resulted in termination of the examination. CONCLUSION: To conclude, the potential relative beneficial aspects of upright, weight-bearing (pMRI), dynamic-kinetic (kMRI) spinal imaging on this system over that of recumbent MRI (rMRI) include: the revelation of occult disease dependent on true axial loading, the unmasking of kinetic-dependent disease, and the ability to scan the patient in the position of clinically relevant signs and symptoms. This imaging unit also demonstrated low claustrophobic potential and yielded relatively high-resolution images with little motion/chemical shift artifact.

Lumbosacral interspinous ligament rupture associated with acute intrinsic spinal muscle degeneration.

OBJECTIVE: To demonstrate lumbosacral interspinous ligament rupture, with or without related paraspinal muscle degeneration. SUBJECTS AND METHODS: This study consisted of a prospective imaging analysis of 100 consecutive MRI studies in adult patients (mean age: 56 years) presenting with low back pain. Alterations from the normal in the inter- and perispinal structures of the spine and perispinal soft tissues (e.g. spinal ligaments, perispinal muscles) were sought based upon studies on young volunteers without low back pain (n = 10; mean age: 23 years). RESULTS: Compared to the group without low back pain, many index cases (n = 71: 71%) demonstrated hyperintensity (i.e., sprain or frank ligamentous rupture) of the interspinous ligament(s) on T2-weighted, fat suppressed MRI studies at one (n = 20/71:28%) or multiple (n = 51/71:72%) levels. Associated paraspinal muscle (e.g., interspinalis, multifidus muscles) degeneration was observed in a minority of cases overall (n = 7: 7%), but was only seen in association with cases also demonstrating interspinous ligament degeneration/rupture (n = 7/71:10%). CONCLUSION: Lumbosacral interspinous ligament sprain or frank rupture, as well as related acute-subacute autotraumatic paraspinal muscle rupture/degeneration, may be overlooked by many observers if fat suppressed, T2-weighted MRI is not acquired. These musculoligamentous alterations are on occasion the only abnormalities recognized on MRI of the lumbosacral spine and may theoretically be sources of low back morbidity that potentially may respond to specific therapy. Because this study was an observational one, based solely upon medical imaging, future research must focus upon the correlation of the relevance of these findings with an age-matched asymptomatic control group and longitudinal clinicoradiologic therapeutic trials.

Lumbosacral interspinous ligament rupture associated with acute intrinsic spinal muscle degeneration.

The objective of this study was to demonstrate lumbosacral interspinous ligament rupture, with or without related acute intrinsic spinal muscle degeneration. This study consisted of a prospective imaging analysis of consecutive 100 MRI studies in adult patients (mean age 56 years) presenting with low back pain. Alterations from the normal in the inter- and perispinal structures of the spine and perispinal soft tissues (e.g., spinal ligaments, perispinal muscles) were sought based upon studies on young volunteers without low back pain ( n=10; mean age 23 years). Compared with the group without low back pain, many index cases ( n=71, 71%) demonstrated hyperintensity (i.e., sprain or frank ligamentous rupture) of the interspinous ligament(s) on T2-weighted, fat-suppressed MRI studies at one (20 of 71, 28%) or multiple (51 of 71, 72%) levels. Associated intrinsic spinal muscle (e.g., interspinalis, multifidus muscles) degeneration was observed in a minority of cases overall ( n=7, 7%), but was only seen in association with cases also demonstrating interspinous ligament degeneration/rupture (7 of 71, 10%). Lumbosacral interspinous ligament sprain or frank rupture, as well as related acute-subacute autotraumatic intrinsic spinal muscle rupture/degeneration, may be overlooked by many observers if fat-suppressed, T2-weighted MRI is not acquired. These musculoligamentous alterations are on occasion the only abnormalities recognized on MRI of the lumbosacral spine and may theoretically be sources of low back morbidity that potentially may respond to specific therapy. Because this study was an observational one, based solely upon medical imaging, future research must focus upon the correlation of the relevance of these findings with an age-matched asymptomatic control group and longitudinal clinicoradiologic therapeutic trials.

Intrathecal gadolinium (gadopentetate dimeglumine) enhanced magnetic resonance myelography and cisternography: results of a multicenter study.

RATIONALE AND OBJECTIVES: This cooperative multicenter human study was designed to evaluate the safety, magnetic resonance (MR) imaging characteristics, and clinical response to a single gadolinium contrast agent: gadopentetate dimeglumine. MATERIAL AND METHODS: Ninety-five patients (age range: 1 month to 78 years; sex: 50 males, 45 females) were included in this prospective study. The patients presented clinically with a variety of cranial or spinal signs and symptoms for which an intrathecal contrast myelogram or cisternogram was requested by clinical staff. Via lumbar puncture (20-25 g needle), 3 to 5 mL/ml of cerebrospinal fluid were withdrawn and mixed with a single volume of 0.5 (n = 63), 0.7 (n = 13), 0.8 (n = 12), or 1.0 (n = 7) cc/mL of gadopentetate dimeglumine (Magnevist; Schering, Berlin, Germany). This was then injected into the subarachnoid space, and the needle was removed. Immediate and delayed (up to 96 hours) T1- and T2-weighted MR imaging was performed on super conductive, high-field (1.0-1.5 tesla) imaging units in two or three planes. All patients were hospitalized for an observation period of 24 hours following the procedure, and follow-up neurologic examinations were performed serially for 6 to 12 months afterward. RESULTS: No patient manifested gross behavioral changes, neurologic alterations, or seizure activity at any time following the procedure. Nineteen patients (20%) experienced postural postlumbar puncture headache, six patients had nausea (6%), and two patients had episodes of vomiting (2%), all which resolved within the first 24 hours of the lumbar puncture with conservative bed rest. CONCLUSION: This cooperative study demonstrates the general safety and feasibility of low dose (0.5-1.0 mL/ml) intrathecal gadopentetate dimeglumine administration. The potential useful clinical applications include the evaluation of obstructions and communications of the various subarachnoid spaces, spontaneous or traumatic/postsurgical craniospinal cerebrospinal fluid leaks, and subarachnoid space CSF flow and parenchymal CNS interstitial diffusion dynamics. This worldwide cooperative study seeks to progressively perform human studies for further definitive evaluation of the practical clinical applications, of the relationship of this technique to other imaging studies and modalities, and the long-term safety of the procedure in a larger number of subjects.

Intrathecal gadolinium-enhanced MR cisternography in the evaluation of clinically suspected cerebrospinal fluid rhinorrhea in humans: early experience.

In this prospective multicenter study, the authors evaluated the utility of magnetic resonance (MR) cisternography after intrathecal administration of gadopentetate dimeglumine in 15 patients clinically suspected of having cerebrospinal fluid (CSF) rhinorrhea. By means of lumbar puncture, a single dose of 0.5 mL of gadopentetate dimeglumine was injected into the lumbar subarachnoid space. Thirteen patients showed leakage of contrast material through the cribriform plate into the ethmoid or sphenoid air cells. No leakage was observed in two patients. The study results show the relative safety and feasibility of low-dose gadolinium-enhanced MR cisternography in confirming the presence and determining the focus of active CSF leaks.