Lumbar herniated disk disease and canal stenosis: prospective evaluation by surface coil MR, CT, and myelography

Sixty patients with suspected lumbar herniated disk and/or canal stenosis were studied prospectively with surface coil MRI, CT, and/or myelography, and the results were compared with the surgically confirmed abnormality. Forty-eight patients had lumbar surgery at 62 levels. There were no negative explorations. Thirty-nine patients had a myelogram and CT. Thirty of the CTs were performed following the injection of metrizamide for myelography. Nine patients had a CT without intrathecal contrast material 1 to several days before the myelogram. Six patients had myelography only, and three patients had CT only. All studies were evaluated for the location and type of disease in a forced choice fashion. Independent of the surgically correlated levels, there was 86.8% agreement between the MR and CT studies in all patients at 151 levels and 87.2% agreement between MR and myelography at 218 levels. At the operative levels, there was 82.6% agreement between MR and surgical findings for both type and location of disease; 83% agreement between CT and surgical findings; and 71.8% agreement between myelography and surgical findings. There was 92.5% agreement when MR and CT were used jointly, and 89.4% agreement when CT and myelography were used jointly. The results of this study indicate that a technically adequate MR examination was equivalent to CT and myelography in the diagnosis of lumbar canal stenosis and herniated disk disease. CT and MR can be complementary studies, and surface coil MR can be viewed as an alternative to myelography.     

Cervical carcinoma: MR imaging with an endorectal surface coil

Ten consecutive patients with biopsy-proved invasive cervical carcinoma underwent magnetic resonance (MR) imaging with both a standard body coil and with an endorectal surface coil. The endorectal coil provided a markedly improved signal-to-noise ratio, enabling the use of small fields of view; thus, the images had significantly improved in-plane resolution. The images were assigned an MR imaging stage based on the clinical staging system of the International Federation of Gynecology and Obstetrics. Vaginal wall, vaginal fornix, parametrium, and pelvic side-wall invasion by tumor were all well demonstrated. When compared with body coil images, the endorectal coil images provided increased anatomic detail and demonstrated tissue planes between tumor and normal structures that were not seen on the body coil images. This preliminary investigation indicates that use of an endorectal surface coil is a promising technique to obtain high-resolution images of the female genital tract. This technique has the potential to improve the accuracy of staging for cervical carcinoma.     

Cervical myelography with metrizamide (amipaque)

Summary Cervical myelography with metrizamide was performed in a series of 30 patients. Minor modifications to the conventional technique made it possible to carry out measurements of the sagittal diameter of the cord and to improve the opacification of the upper cervical —foramen magnum region. Computer tomography was performed with a head scanner within 1 h after the conventional examination, and the spinal cord surrounded by contrast medium was shown from C-3 to the foramen magnum region. Measurements of the sagittal diameter of the spinal canal and the cord at corresponding levels using the two methods showed good correlation.     

Outpatient metrizamide myelography: prospective evaluation of safety and cost effectiveness

A group of 228 consecutive patients undergoing metrizamide myelography was prospectively evaluated for postprocedure symptoms. The observed prevalence of these symptoms concurs with previously reported inpatient studies, with the most common sequelae being exacerbation or onset of spine or extremity pain, headache, nausea, and paresthesia. Limitation of administered dose of metrizamide in lumbar myelography may slightly reduce the occurrence of common symptoms, but withdrawal of contrast medium at the completion of examination had no impact on their occurrence. There was a higher occurrence of paresthesia in cervical myelography, but otherwise there was no significant difference in symptoms between cervical and lumbar studies. Outpatient metrizamide myelography can be performed with relative safety with the potential for significant cost savings.     

Cervical radiculopathy: value of oblique MR imaging

Eighteen patients with cervical radiculopathy were entered into a prospective study to compare the accuracy of surface coil magnetic resonance (MR) imaging with that of metrizamide myelography and computed tomography (CT) with metrizamide. All MR studies included tailored axial and oblique images as well as routine sagittal images. All imaging studies were evaluated for topography and type of disease. Nine of 18 patients subsequently underwent cervical surgery with an anterior interbody approach at 11 levels. The surface coil MR findings concerning disease topography and type concurred with the surgical findings at nine of 11 levels (82%). At three levels, the oblique view added important information not available on the sagittal images or clarified changes seen on the axial images. Metrizamide myelography with CT metrizamide myelography had findings concurrent with surgical findings at ten of 11 levels (91%).     

Posttraumatic progressive myelopathy. Clinical and radiologic correlation employing MR imaging, delayed CT metrizamide myelography, and intraoperative sonography

Posttraumatic progressive myelopathy (PTPM) was studied in nine patients and grouped into three categories on the basis of characteristic radiographic findings and response to therapy: (a) myelomalacia with no cystic degeneration, which has poor response to therapy; (b) small cysts, with poor response to therapy; and (c) large cysts, which are effectively treated by decompression. One type dominated in each patient, although a mixture of types was present in each. Magnetic resonance (MR) imaging gave slightly improved resolution and specificity of type, decreased morbidity, and simplification of procedure in comparison with imaging by delayed computed tomographic metrizamide myelography (DCTM). DCTM and MR imaging results correlated nearly equally with those of intraoperative sonography (IOS) and pathologic study at surgery. IOS was superior to DCTM or MR imaging in detecting septations and small additional cysts. IOS also was helpful in myelotomy positioning, shunt placement, and verification of cyst decompression. MR imaging may replace DCTM in the preoperative evaluation of PTPM, followed by IOS imaging as indicated. Patients with nonmyelopathic signs and symptoms (e.g., radiculopathy) probably still require study with conventional and/or CT myelography.     

Cervical radiculopathy: computed tomography and myelography compared

The accuracy of CT in the determination of cervical disk herniation has not been measured as it has in the determination of lumbar disk disease. Cervical myelograms and CT scans of patients with cervical radiculopathy secondary to disk herniation or spondylosis, which was verified by clinical examination, surgery, and in most cases EMG, were evaluated blindly and independently, results were analyzed statistically, and receiver operating characteristic (ROC) curves were calculated. CT without or with the use of intrathecal metrizamide was more accurate than myelography in the identification of lesions that caused cervical radiculopathy. In some patients, CT obviates the need for cervical myelography. With improvement in CT techniques and more experience in interpreting the images, CT will be increasingly important in the evaluation of cervical radiculopathy.     

Tendons: high-field-strength, surface coil MR imaging

High-resolution magnetic resonance (MR) images of the tendons of the hands, wrists, feet, and ankles of six healthy volunteers and six cadavers were obtained using receive-only surface coils and reduced-field-of-view imaging. Normal anatomy was identified and compared with gross anatomic sections of the six cadavers. Experimentally produced tears of the calcaneal (Achilles) tendon in domestic swine were identified on MR images. The hands and feet of 11 patients were examined, and a variety of pathologic lesions were identified, including acute posttraumatic rupture, acute tenosynovitis, chronic tendonitis, and postsurgical complications. MR imaging provides inherently greater soft-tissue contrast than any other currently available imaging modality. With the use of surface coils and reduced-field-of-view imaging to enhance spatial resolution, MR imaging has become a valuable tool for imaging tendons. Advantages over other available modalities include excellent depiction of anatomic detail, superior contrast resolution, and the potential for multiplanar imaging.     

Cervical and lumbar metrizamide myelography. Split-dose technique

Good- or excellent-quality cervical and lumbar myelograms may be obtained without exceeding the maximum recommended dose of metrizamide and without using special equipment. With the patient's head down, highly concentrated metrizamide was injected via the lumbar approach to opacify the cervical subarachnoid space. Later, with the patient's head up, additional contrast media was used to opacify the lumbar subarachnoid space. Excellent or good cervical and lumbar myelograms were obtained in 18 of 21 instances.     

Cervical disk syndromes: value of metrizamide myelography and diskography

This paper reports on the respective diagnostic values of myelography with water-soluble contrast media and diskography in a study of 100 patients examined between 1979 and 1981 and operated on because of cervical disk disease. The results of the study led to a change of the diagnostic procedures formerly applied in radicular syndromes (i.e., diskography, and then perhaps myelography) and in cervical myelopathy (myelography, rarely followed by diskography). Now cervical metrizamide myelography is always performed first. Diskography is only indicated in radicular syndromes to determine the segment causing clinical symptoms when there is a polysegmental space-occupying lesion on the myelogram in combination with a mono- or oligoradicular neurologic symptomatology; or in the case of a normal myelogram with complaints resistant to conservative treatment.     

Prostate: MR imaging with an endorectal surface coil

An endorectal surface coil has been developed to obtain high-resolution magnetic resonance images of the prostate. The probe consists of a surface coil mounted on the inner surface of a balloon. The balloon is concave to ensure tight seating against the prostate. The coil has been used in 15 patients with biopsy-proved prostatic carcinoma and in two healthy volunteers. The axial images were obtained with a 12-16-cm field of view and a 3-mm section thickness. Compared with images obtained with a body coil, the surface coil images better demonstrate prostatic anatomy and pathologic conditions.     

Orbital fractures: surface coil MR imaging

Twenty-six patients with orbital fractures diagnosed with plain radiography and computed tomography were examined with surface coil magnetic resonance (MR) imaging. Fifteen patients had blow-out fractures, and 11 had maxillofacial complex fractures. In all patients with blow-out fractures, the location of the fracture was precisely indicated by the presence of prolapsed orbital fat. Incarceration of the extraocular muscle or orbital fat was correctly diagnosed with MR imaging, which was less sensitive in depicting maxillofacial fractures but was useful in assessment of soft-tissue involvement. Postoperative follow-up MR studies provided valuable information about the cause of motility impairment. While T1-weighted images are useful for the detection of the fracture site, both T1- and T2-weighted images are usually necessary for evaluating soft-tissue lesions. The results of this study indicate that surface coil MR imaging is an important adjunct procedure in the diagnosis and treatment of orbital fractures.     

Lumbar myelography with iohexol and metrizamide: a comparative multicenter prospective study

Diagnostic quality of radiographs and adverse reactions associated with the use of metrizamide and iohexol as contrast agents in lumbar myelography were compared in a prospective randomized double blind study in 350 patients at seven centers. The contrast media were administered in comparable volumes at a concentration of 180 mg I per ml. Overall quality of radiographic visualization was graded good or excellent in 95% of 175 metrizamide studies and in 98% of 175 iohexol studies. Ninety-three patients examined using metrizamide (53%) and 130 patients examined using iohexol (74%) experienced no discomfort during or after myelography. Postmyelographic headache was associated with 38% of metrizamide examinations and 21% of iohexol examinations. Nausea and vomiting were also more common with metrizamide. Five patients examined using metrizamide (3%) experienced transient confusion and disorientation following lumbar myelography. No such reactions were observed following iohexol myelography.     

Acquired spinal subarachnoid cysts: evaluation with MR, CT myelography, and intraoperative sonography

Fifteen patients with acquired spinal subarachnoid cysts (14 surgically proved, one presumed) were evaluated preoperatively with immediate and/or delayed CT myelography (seven patients), MR (11 patients), or both (three patients). CT myelography separated subarachnoid cyst from myelomalacia and/or intramedullary cysts in four cases but failed to diagnose them in three, while MR accurately diagnosed subarachnoid cyst in all 10 cases that were also surgically proved. The results of these preoperative examinations were evaluated to determine the efficacy of each study in diagnosing subarachnoid cysts, ascertaining their extent and internal architecture, and detecting associated abnormalities of the spinal cord. In addition, during surgery these cysts were studied with sonography to gain an understanding of the pathophysiological mechanisms involved in their formation and propagation and to guide the surgeon in their decompression. On the basis of our experience, MR appears to be the most efficient preoperative study in diagnosing and characterizing acquired subarachnoid cyst and associated abnormalities. Intraoperative sonography provides a reliable means of ensuring adequate decompression of these cysts.     

Acquired spinal subarachnoid cysts: evaluation with MR, CT myelography, and intraoperative sonography

Fifteen patients with acquired spinal subarachnoid cysts (14 surgically proved, one presumed) were evaluated preoperatively with immediate and/or delayed CT myelography (seven patients), MR (11 patients), or both (three patients). CT myelography separated subarachnoid cyst from myelomalacia and/or intramedullary cysts in four cases but failed to diagnose them in three, while MR accurately diagnosed subarachnoid cyst in all 10 cases that were also surgically proved. The results of these preoperative examinations were evaluated to determine the efficacy of each study in diagnosing subarachnoid cysts, ascertaining their extent and internal architecture, and detecting associated abnormalities of the spinal cord. In addition, during surgery these cysts were studied with sonography to gain an understanding of the pathophysiological mechanisms involved in their formation and propagation and to guide the surgeon in their decompression. On the basis of our experience, MR appears to be the most efficient preoperative study in diagnosing and characterizing acquired subarachnoid cyst and associated abnormalities. Intraoperative sonography provides a reliable means of ensuring adequate decompression of these cysts.     

Iopamidol and metrizamide for myelography: prospective double-blind clinical trial

In a comparative randomized double-blind study, 73 patients underwent myelography using iopamidol (36 patients) or metrizamide (37 patients) as contrast medium. The overall diagnostic adequacy of iopamidol myelography was found to be comparable to that of metrizamide myelography. The incidence of examinations graded as superior (64%) or adequate (36%) with iopamidol was equivalent to that with metrizamide (57% superior, 43% adequate). Adverse reactions after iopamidol myelography were fewer, less severe, and generally of shorter duration than those associated with metrizamide. In the iopamidol group, adverse reactions occurred in nine (25%) patients, all of whom experienced mild or moderate headache, one with nausea, vomiting, and fatigue. In the metrizamide group, adverse reactions occurred in 17 (46%) patients, all of whom experienced mild or moderate headache, six with nausea and vomiting and four with back and leg pain. Of nine individuals who underwent myelography using 300 mg 1/ml metrizamide injected via lateral C1-C2 puncture, three experienced a toxic encephalopathy with confusion, dysphasia, headache, nausea, and vomiting, and a fourth individual suffered severe nausea, vomiting, fever, and irregular pulse. Encephalopathy was not observed in any of the 11 patients in whom myelography was performed via lateral C1-C2 puncture with a similar concentration of iopamidol. No seizures were encountered, and no clinically significant changes in laboratory studies were observed with either contrast medium.     

Detection of focal hepatic masses: prospective evaluation with CT, delayed CT, CT during arterial portography, and MR imaging

The sensitivities of contrast medium-enhanced computed tomography (CT), delayed CT (DCT), CT during arterial portography (CTAP), and magnetic resonance (MR) imaging for detecting focal liver lesions were prospectively evaluated in eight patients who subsequently underwent hepatic lobectomy or transplantation. Pathologic evaluation of the resected liver specimens demonstrated 37 lesions. The sensitivities were 81% (30 of 37 lesions) for CTAP, 57% (21 of 37 lesions) for MR imaging, 52% (12 of 23 lesions) for DCT, and 38% (14 of 37 lesions) for contrast-enhanced CT. The difference between the sensitivity of CTAP and the sensitivities of the other imaging tests was statistically significant (P less than .004). Of the lesions smaller than 1 cm in diameter, CTAP depicted 61% (11 of 18 lesions), MR imaging 17% (three of 18 lesions), CT 0% (zero of 18 lesions), and DCT 0% (zero of nine lesions). It is concluded that for preoperative detection of focal hepatic masses, CTAP is the most accurate technique available to most radiologists. Patients with primary or secondary hepatic neoplasms who are being considered for hepatic resection should undergo CTAP as part of their preoperative examination.     

CT myelography and MR imaging of acute transverse myelitis

Two patients with acute transverse myelitis were evaluated by both CT myelography and magnetic resonance. Computed tomographic myelography showed fusiform cord enlargement involving several levels; one patient had a subtotal block in the thoracic spine. Magnetic resonance displayed similar findings of cord enlargement. The demonstration of cord swelling in acute transverse myelitis is an uncommon radiologic manifestation of the disease.     

Clinical MR imaging with a Helmholtz-type surface coil

Limited-field-of-view radio-frequency receiver antennas provide improved near-field sensitivity for magnetic resonance imaging by decreasing the antenna volume. The Helmholtz-type surface coil, consisting of two flat rings, is an organ-encompassing antenna that takes advantage of this principle to yield an improved signal-to-noise ratio (S/N). The coil was tested in a group of 50 patients and 16 healthy volunteers. Images obtained with the Helmholtz coil demonstrated quantitatively superior S/N of 2.2-fold or greater than that of comparison body coil images, as well as qualitatively superior anatomic resolution.