Radiation myelopathy in over-irradiated patients: MR imaging findings

The objective of this work is to report the MRI findings in patients with radiation myelopathy due to accidental local over-irradiation syndrome. Eight patients (seven males and one female) were suffering from over-irradiation syndrome as a result of treatments from a malfunctioning linear electron accelerator. The mean accidental estimated dose was 136 Gy delivered to the “open-neck” (seven cases) and to the thoracic wall (one case), during a mean of 5.4 sessions (range 1–9 sessions). Paresthesia and weakness in the upper extremities were the earliest symptoms (87.5 %), with evolution to paralysis in all patients. No patient is alive (mean survival time 64 days). In all cases MRI was negative for neurologic lesions in the acute phase ( < 90 days from irradiation; Radiation Therapy Oncology Group scoring system). Late signs of radiation myelitis manifested as high-intensity signals on T2-weighted images in three patients, and as Gd-DTPA enhancement of T1-weighted images in one case. Autopsies performed on four patients who died in acute phase showed morphologic alterations in white matter: edema in 75 %, and necrosis and glial reaction as well as obliterative vasculitis in all cases. In cases of over-irradiation, MRI may be normal in acute phase even if the patients have severe neurologic deficit, as positive MRI findings appear only in delayed radiation myelitis. Received 25 March 1996; Revision received 3 July 1996; Accepted 4 September 1996     

MR delayed enhancement imaging findings in suspected acute myocarditis

The purpose of the study was to prospectively assess the clinical impact of routinely performed delayed enhancement imaging in suspected acute myocarditis. A two-centre prospective study was performed in patients with suspected acute myocarditis. The protocol included horizontal long axis, vertical long axis and short axis ciné MR and delayed enhancement imaging after Gd-DTPA infusion (0.2 mmol/kg). Sixty consecutive patients were enrolled (aged 49.4?±?17.8 years). MRI demonstrated delayed enhancement sparing the subendocardicardial layer in 51.6% of patients, concordant with the diagnosis of acute myocarditis; 16.7% of patients exhibited delayed enhancement involving the subendocardial layer with irregular margins, concordant with the diagnosis of acute myocardial infarction; 31.7% of patients had delayed enhancement imaging that was considered normal. Routine imaging to identify delayed enhancement provided crucial information in suspected acute myocarditis by reinforcing the diagnosis in 51.6% of patients and correcting a misdiagnosed acute myocardial infarction in 16.7% of patients.     

MR findings in AIDS-associated myelopathy.

BACKGROUND AND PURPOSE: The most common cause of spinal cord disease among patients with AIDS or those infected with HIV-1 is AIDS-associated myelopathy. The purpose of this study was to determine the MR characteristics of the spinal cord in this patient population and to correlate these findings with the clinical severity of myelopathy. METHODS: MR images of the spinal cord in 21 patients with documented HIV-1 infection or AIDS and a clinical diagnosis of AIDS-associated myelopathy were assessed retrospectively for atrophy, intrinsic signal abnormality, and abnormal enhancement. The clinical severity of myelopathy was graded by a neurologist on the basis of physical examination, and a qualitative correlation was made with the MR findings. RESULTS: MR findings were abnormal in 18 of the 21 patients. The most common feature was spinal cord atrophy (n = 15), typically involving the thoracic cord with or without cervical cord involvement, followed by intrinsic cord signal abnormality (n = 6), and normal-appearing cord (n = 3). Three patients had both cord atrophy and intrinsic cord signal abnormality. The cord signal abnormality was diffuse, without predilection for any specific distribution pattern. Enhancement was not seen in any of the 10 patients who received intravenous contrast material. Only one of 16 patients with moderate to severe myelopathy had normal MR findings, as compared with two of five patients with mild myelopathy. CONCLUSION: MR findings in the spinal cord are abnormal in the majority of patients with AIDS-associated myelopathy, typically showing spinal cord atrophy, with or without intrinsic cord signal abnormality. Patients with moderate to severe myelopathy have an increased frequency of spinal cord abnormalities, but a definite correlation between clinical severity of myelopathy and extent of MR abnormalities remains to be established.     

MR imaging in radiation myelopathy.

PURPOSE: Using MR imaging, we assessed the signal, size, and enhancing characteristics of the cervical cord in patients in whom radiation myelopathy developed after radiotherapy for nasopharyngeal carcinoma. PATIENTS AND METHODS: Ten patients, 3 men and 7 women, aged from 32 to 77 years, were included. MR imaging was performed 1 to 53 months after clinical manifestations of myelopathy. RESULTS: Two cases showed atrophy of the cervical cord without abnormal signal intensity; in the others, a long segment of the cervical cord demonstrated low signal intensity on T1-weighted images and high signal intensity on T2- or T2*-weighted images. Some of these cases also showed swelling of the cord. Focal enhancement at C1-C2 area after intravenous administration of Gd-DTPA was seen in four cases. CONCLUSIONS: There is a correlation between the time of MR imaging after onset of symptoms and MR findings. When MR scans were obtained more than 3 years after onset of symptoms, atrophy of the cervical cord was noted without abnormal signal intensity. When MR was performed less than 8 months after onset of symptoms, a long segment of the cervical cord demonstrated abnormal signal intensity with or without associated swelling of the cord and focal enhancement.     

Detection of postoperative residual cholesteatoma with delayed contrast-enhanced MR imaging: initial findings

Our objective was to assess the value of delayed contrast-enhanced T1-weighted spin-echo MR imaging in the detection of residual cholesteatoma in patients who have undergone canal wall-up tympanoplasty procedure. The MR imaging was obtained prior to revision surgery in 18 patients with opacity of the post-operative cavity at CT examination 12–18 months after canal wall-up tympanoplasty. In each patient the following was performed: precontrast T1- and T2-weighted images; and early and delayed contrast-enhanced axial and coronal T1-weighted imaging. Early and delayed MR imaging results were separately compared with surgical second-look findings. Sensitivity, specificity, and predictive values were evaluated for early and delayed post-contrast MR imaging, compared with second-look surgery findings. A residual cholesteatoma was correctly identified in 8 of 9 cases with delayed contrast-enhanced T1-weighted MR imaging. Mean sensitivity, specificity, positive predictive value, and interobserver agreement (evaluated by kappa statistics) were, respectively, 85.2, 92.6, 92.6%, and kappa=0.78 for the delayed contrast-enhanced MR imaging technique. The same parameters were, respectively, 96.3, 33.3, 60.6, and 0.30 for the early contrast-enhanced T1-weighted MR images. We conclude that delayed contrast-enhanced T1-weighted MR imaging is reliable for the detection of residual cholesteatomas of the middle ear in patients who have undergone canal wall-up tympanoplasty. Electronic Publication     

MR imaging findings in hepatic encephalopathy

The term hepatic encephalopathy (HE) includes a spectrum of neuropsychiatric abnormalities occurring in patients with liver dysfunction. Most cases are associated with cirrhosis and portal hypertension or portal-systemic shunts, but the condition can also be seen in patients with acute liver failure and, rarely, with portal-systemic bypass and no associated intrinsic hepatocellular disease. Although HE is a clinical condition, several neuroimaging techniques, particularly MR imaging, may eventually be useful for the diagnosis because they can identify and measure the consequences of central nervous system (CNS) increase in substances that under normal circumstances, are efficiently metabolized by the liver. Classic MR imaging abnormalities include high signal intensity in the globus pallidum on T1-weighted images, likely a reflection of increased tissue concentrations of manganese, and an elevated glutamine/glutamate peak coupled with decreased myo-inositol and choline signals on proton MR spectroscopy, representing disturbances in cell-volume homeostasis secondary to brain hyperammonemia. Recent data have shown that white matter abnormalities, also related to increased CNS ammonia concentration, can also be detected with several MR imaging techniques such as magnetization transfer ratio measurements, fast fluid-attenuated inversion recovery sequences, and diffusion-weighted images. All these MR imaging abnormalities, which return to normal with restoration of liver function, probably reflect the presence of mild diffuse brain edema, which seems to play an essential role in the pathogenesis of HE. It is likely that MR imaging will be increasingly used to evaluate the mechanisms involved in the pathogenesis of HE and to assess the effects of therapeutic measures focused on correcting brain edema in these patients.     

MR imaging findings in cerebrospinal gnathostomiasis

Human gnathostomiasis is an infection caused mainly by Gnathostoma spinigerum, a nematode. Infected humans can present with various clinical manifestations. Serology is the criterion standard for diagnosing gnathostomiasis, whereas MR imaging represents a complementary tool for assessing severity and extent of disease. We report two definite cases of gnathostomiasis that were confirmed by the immunoblotting technique. MR imaging of the cervical cords showed cord enlargement and diffuse high signal intensity, mainly of the gray-white matter regions. MR imaging of the brain showed hemorrhagic tract and scattered deep intracerebral hemorrhage with diffuse, fuzzy white matter lesions with nodular enhancement. Severe gnathostomiasis was unresponsive to treatment.     

MR imaging findings in African trypansomiasis

We report the initial and follow-up brain findings in a 42-year-old male patient with CNS involvement with African trypansomiasis. Initial MR imaging demonstrated diffuse hyperintensity in the basal ganglia bilaterally as well as involvement of the internal capsule, external capsule, and extreme capsule. Follow-up examination at 1 year revealed decreased signal intensity in the previously affected areas; however, ventricular enlargement indicative of atrophy was readily apparent.     

Sacroiliitis: MR imaging findings

Magnetic resonance (MR) imaging was performed in seven asymptomatic volunteers and 17 patients with clinical and radiologic evidence of sacroiliitis. MR imaging findings were compared with those at computed tomography (CT) to determine the MR imaging appearance of the sacroiliac joint when normal and in sacroiliitis. The normal articulation was well depicted with MR imaging. Findings of sacroiliitis were identified in 20 sacroiliac joints (12 patients). MR imaging findings characteristic of sacroiliitis included abnormal cartilage signal intensity (95% of joints) and erosions (75% of joints) on T1-weighted images. Areas of increased intensity in the articulation (80% of joints) or in erosions (60% of joints) were seen on T2-weighted images. MR imaging was superior to CT for evaluation of cartilage and detection of erosions. Four sacroiliac joints (20%) and two patients (17%) with MR imaging findings of sacroiliitis were negative at CT. The authors conclude that MR imaging is a valuable method for detecting sacroiliitis, particularly when results of other imaging techniques are inconclusive.     

MR imaging of reversible cyclosporin A-induced neurotoxicity

Neurotoxicity is a recognized complication of cyclosporin A (CsA) therapy in patients undergoing organ transplantation. It is most commonly manifested by fever, seizures, and altered mental status. Cortical blindness and speech and motor disturbances can also occur. Changes seen in cerebral white matter on imaging studies are nonenhancing areas of hypoattenuation on CT and T2 prolongation on MR. We report three cases of CsA-induced neurotoxicity in which reversible changes were observed in the cerebral white matter. In the first patient, CsA neurotoxicity occurred 1 week following orthotopic liver transplantation. In the second patient, CsA neurotoxicity coincided with an episode of severe systemic hypertension 4 weeks after cardiac transplantation. The third patient experienced seizures 1 month after heart/lung transplantation for cystic fibrosis. A current theory postulates a relationship between diminished serum cholesterol and CsA neurotoxicity. This theory, however, does not satisfactorily address all cases of CsA neurotoxicity. In particular, serum cholesterol measurements were normal in cases 2 and 3 and probably were normal in case 1, despite diminished cholesterol levels preoperatively. Although the matter of CsA-induced neurotoxicity remains unresolved, we suggest that endothelin, a newly described neuropeptide that causes intense vasoconstriction and that has been implicated in cerebral vasospasm, may potentiate CsA-induced damage to endothelium and promote CsA neurotoxicity.     

Compressive myelopathy: magnetic resonance imaging findings simulating idiopathic acute transverse myelopathy

Objective

To provide magnetic resonance imaging (MRI) findings of compressive myelopathy simulating idiopathic acute transverse myelopathy (ATM).

Materials and methods

From 19,416 patients who had spinal MRI from 1 September 2004 to 10 July 2011, the patients who met inclusion criteria were enrolled as follows: (1) definable cord compression, (2) long-segmental intramedullary T2-high signal intensity (HSI) extending more than 2 vertebral segments, and (3) no history of trauma, malignancy, or demyelinating disease. The characteristics of T2-HSI and contrast enhancement pattern were analyzed. The patients’ clinical information was collected in the process.

Results

Thirteen patients (10 men, 3 women; mean age, 52.8 years; age range, 43–77 years) were included in this study. Twelve patients had cervical cord compression and one had thoracic compression. Common findings of T2-HSI included fusiform shape (100 %) with cord swelling (92.3 %), cord compression in midline location (76.9 %), diffuse distribution occupying more than two-thirds of the cross-sectional dimension of the cord in axial image (84.6 %), and focal and peripheral enhancement (63.6 %). Intravenous corticosteroid was administered to four patients, including two patients following decompressive surgery, and interval decrease in T2-HSI was seen in three patients, but with residual lesions at cord compression level.

Conclusions

Spinal cord compression can induce long-segmental cord signal change, such as idiopathic ATM.     

HTLV-I-associated myelopathy: acute progression and atypical MR findings.

We describe serial MR imaging findings in a patient with HTLV-I-associated myelopathy. The patient had acute progression of neurologic symptoms and exhibited swelling of the entire length of the spinal cord with increased T2 signal and contrast enhancement on MR imaging. The spinal cord became atrophic a few years later.     

MR imaging findings in cauda equina gnathostomiasis

We report a case of cauda equina syndrome caused by Gnathostoma spinigerum, which was confirmed by an immunoblotting test. MR imaging of the lumbosacral spine showed long, segmented hyperintensity along the cauda equina with irregular enhancement on the postcontrast study. The conus medullaris was slightly enlarged with abnormal enhancement. The patient was treated with corticosteroids, and her clinical condition improved. MR imaging, 9 months after treatment, showed the condition to be completely resolved.     

MR imaging findings in spring ligament insufficiency

Objective. Spring ligament insufficiency is associated with chronic posterior tibial tendon dysfunction, and may constitute an indication for surgical repair or reconstruction. This study examines the accuracy of MRI for the diagnosis of insufficiency of the spring ligament. Design and patients. Two experienced musculoskeletal radiologists independently scored the MRI findings in 13 cases of surgically proven spring ligament insufficiency and in 18 control subjects, using a standardized scoring system. Results. Insufficiency of the spring ligament was associated with increased signal heterogeneity on short TE spin echo images, and an increase in the thickness of the medial portion of the ligament. The sensitivity of MRI for the diagnosis of spring ligament insufficiency was 54–77%, while the specificity was 100%. MRI assessment of the plantar portion of the spring ligament was unreliable (kappa=0.33), but the assessment of global ligament integrity was substantially reproducible (kappa=0.76). Conclusion. The medial portion of the spring ligament can be reliably assessed on routine MRI. The findings of spring ligament insufficiency on MRI are only moderately sensitive but highly specific. Received: 12 August 1998 Revision requested: 8 October 1998 Revision received: 21 January 1999 Accepted: 26 January 1999