Parenchymal abnormalities associated with cerebral venous sinus thrombosis: assessment with diffusion-weighted MR imaging

BACKGROUND AND PURPOSE: The common entity cerebral venous sinus thrombosis is associated with the poorly characterized imaging finding of parenchymal abnormalities; diffusion-weighted imaging has offered some insight into these manifestations. We assessed the relationship between the diffusion constant from apparent diffusion coefficient (ADC) maps in patients with cerebral venous thrombosis (CVT) with follow-up imaging findings and clinical outcome. METHODS: We evaluated the medical records and T2-weighted MR images of 13 patients with CVT complicated by intraparenchymal abnormality. Diffusion-weighted (DW) images and ADC maps were evaluated for increased, decreased, or unchanged signal intensity and were compared with signal intensity of contralateral, normal-appearing brain. In addition, ADCs were obtained in nine pixel regions of interest in abnormal regions in eight of the 13 patients. RESULTS: Eight patients had superficial CVT, and five had superficial and deep CVT. CVT of deep veins was associated with deep gray nucleus and deep white matter abnormalities, whereas superficial CVT was associated with cortical and subcortical abnormalities. Twenty-four nonhemorrhagic lesions were identified in 10 of 13 patients on the basis of follow-up imaging findings. Four patients without seizures had lesions with decreased diffusion that appeared hyperintense on follow-up T2-weighted images, three patients with seizures had lesions with decreased diffusion that resolved, and seven patients had lesions with increased diffusion that resolved. Three of 10 patients had more than one lesion type. No difference was noted in mean ADCs for lesions with decreased diffusion that resolved compared with lesions with decreased diffusion that persisted. CONCLUSION: DW imaging in these patients disclosed three lesion types: lesions with elevated diffusion that resolved, consistent with vasogenic edema; lesions with low diffusion that persisted, consistent with cytotoxic edema in patients without seizure activity; and lesions with low diffusion that resolved in patients with seizure activity. This information may be important in prospectively determining severity of irreversible injury and in patient treatment.     

Reversible MR imaging and MR spectroscopy abnormalities in association with metronidazole therapy

We present a report of MRI and proton MR spectroscopy (MRS) findings in an adolescent patient with Down syndrome and Crohn disease treated with metronidazole. MRI revealed signal abnormalities within the corpus callosum, basal ganglia, and brainstem. Proton MRS examination demonstrated a persistent lactate elevation during metronidazole treatment. Clinical, spectroscopic, and imaging abnormalities resolved with discontinuation of metronidazole.     

Temporomandibular joint abnormalities associated with rheumatic disease: comparison between MR imaging and arthrotomography.

Nonenhanced magnetic resonance (MR) images and arthrotomograms of temporomandibular joints (TMJs) were compared in 18 patients with rheumatic disease. Of 22 symptomatic TMJs, arthrotomography was unsuccessful in three (14%). MR imaging showed extensive rheumatic abnormalities in two of these three joints and internal derangement in one. In another three joints (14%), both imaging modalities showed normal findings or internal derangement. In the remaining 16 joints (72%), arthrotomographic findings were interpreted as rheumatic, whereas MR findings were interpreted as rheumatic in 14 joints and as internal derangement in two. Surgical correlation in 11 joints indicated superiority of MR imaging for assessment of moderate and severe rheumatic TMJ involvement. MR imaging seemed to be of limited value in early diagnosis due to its inability to show synovial proliferation. Indirect signs of synovial proliferation could be shown with arthrotomography, which may be helpful in early diagnosis of rheumatic TMJ disease.     

Brain parenchymal signal abnormalities associated with developmental venous anomalies: detailed MR imaging assessment

BACKGROUND AND PURPOSE: The occurrence of brain parenchymal signal-intensity changes within the drainage territory of developmental venous anomalies (DVAs) in the absence of cavernous malformations (CMs) has been incompletely assessed. This study was performed to evaluate the prevalence of brain parenchymal signal-intensity abnormalities subjacent to DVA, correlating with DVA morphology and location.MATERIALS AND METHODS: One hundred sixty-four patients with brain MR imaging with contrast studies performed from July 2005 through June 2006 formed the study group. The examinations were reviewed and data were collected regarding the following: location, depth, size of draining vein, associated increased signal intensity on fluid-attenuated inversion recovery and T2-weighted images, associated CMs, and associated signal intensity on gradient recalled-echo sequences.RESULTS: Of the 175 DVAs identified, 28 had associated signal-intensity abnormalities in the drainage territory. Seven of 28 DVAs with signal-intensity abnormalities were excluded because of significant adjacent white matter signal-intensity changes related to other pathology overlapping the drainage territory. Of the remaining DVAs imaged in this study, 21/168 (12.5%) had subjacent signal-intensity abnormalities. An adjusted prevalence rate of 9/115 (7.8%) was obtained by excluding patients with white matter disease more than minimal in degree. Periventricular location and older age were associated with DVA signal-intensity abnormality.CONCLUSION: Signal-intensity abnormalities detectable by standard clinical MR images were identified in association with 12.5% of consecutively identified DVAs. Excluding patients with significant underlying white matter disease, we adjusted the prevalence to 7.8%. The etiology of the signal-intensity changes is unclear but may be related to edema, gliosis, or leukoaraiosis secondary to altered hemodynamics in the drainage area.

Developmental venous anomalies (DVAs) are encountered frequently on postcontrast MR imaging of the brain and are usually regarded as normal variants of venous development. The association between DVAs and cavernous malformations (CMs) has been well described.^1–3 Intracranial hemorrhage in the absence of CM has been rarely reported as a complication of DVA.⁴ There have also been a few case reports of nonhemorrhagic presumed venous infarction in the drainage territory of the DVA.^5–8 Signal-intensity abnormality on T2-weighted or fluid-attenuated inversion recovery (FLAIR) sequences has been infrequently reported in the drainage territory of DVAs and has not been thoroughly investigated. Although some of the early literature described signal-intensity abnormalities in the adjacent parenchyma, these were in small case series and appeared, in some instances, to be related to prior hemorrhage.^9,10 A more recent investigation reported parenchymal alterations in up to 65% of DVAs by MR imaging and CT evaluation in a retrospectively identified patient population.¹¹ We chose to specifically evaluate the frequency of signal-intensity abnormalities in association with DVAs in a more detailed fashion by evaluating a series of consecutive DVAs identified on MR imaging examinations during a defined time interval and correlating the presence of associated signal intensity with DVA morphology, location, size, and drainage pattern. We also attempted to assess the relationship of other white matter signal-intensity alterations not in the DVA territory to presumed DVA-associated signal-intensity changes.     

MR imaging of fetal abnormalities.

Our purpose was to evaluate the capability of ultrafast single-shot fast spin-echo MR imaging to assess normal fetal anatomy and abnormalities of different fetal organ systems. Fetal MR imaging was performed prospectively in consecutive 40 pregnant women because of abnormal findings or suspected fetal abnormalities on prenatal US. No statistically significant difference between US and MR imaging was found for the detection of abnormality in any organ system. MR imaging was slightly superior to US with regard to cerebral abnormalities only. In four (10%) of 40 fetuses, additional information provided by MR imaging altered counseling. However, MR imaging of the extremities-face and soft tissues was limited because of the lack of real-time information.     

MR imaging of pediatric cerebral abnormalities

One hundred sixteen magnetic resonance (MR) imaging studies from 105 pediatric patients with a variety of cerebral abnormalities were reviewed to determine the diagnostic efficacy of MR in the pediatric population. All subjects tolerated the MR procedure well, although sedation was necessary for younger children. Compared with CT, MR proved to be advantageous in detection and characterization of the pathology in 23 of 105 patients, especially when the abnormality was located along the base of the brain and midline, or when it involved primarily the white matter. Intracranial calcification was the one abnormality not detected with MR although dense calcifications could be seen as areas of low signal intensity. Some characteristics of various pathological entities were compared in an attempt to differentiate among abnormalities in the same anatomical location: craniopharyngioma from optic chiasm and hypothalamic glioma, cystic glioma from arachnoid cyst, and chronic subdural hematoma from subdural hygroma. The lack of ionizing radiation in MR is of particular interest in pediatric neuroradiology since radiation is of special concern in the young age group.     

Wolfram syndrome presenting marked brain MR imaging abnormalities with few neurologic abnormalities

Wolfram syndrome is a rare autosomal recessive disorder featuring diabetes insipidus, diabetes mellitus, optic atrophy, and deafness; DIDMOAD is a commonly accepted anonym for this disorder. We describe a 35-year-old man with Wolfram syndrome, who had marked atrophy of the brain stem, middle cerebellar peduncle, and cerebellum. Despite these MR imaging findings involving the pontocerebellar tract, the patient had no neurologic abnormalities suggesting dysfunction of the brain stem or cerebellum. Patients with Wolfram syndrome may have discrepancies between neurologic and radiologic findings.     

Fetal thoracic abnormalities: MR imaging

PURPOSE: To elucidate the appearance of fetal thoracic abnormalities at prenatal magnetic resonance (MR) imaging and determine whether MR imaging yields information additional to that obtained with ultrasonography (US). MATERIALS AND METHODS: US and MR imaging data from 83 MR examinations of 74 fetuses with thoracic abnormalities and confirmatory US performed within 1 week before MR imaging were compared with respect to resulting changes in patient counseling and/or care. Lung parenchyma and lesion signal intensities and vascularity, airway, esophagus, and diaphragm appearances were reviewed retrospectively on MR images. Student t tests and analyses of variance were performed. RESULTS: MR imaging yielded information additional to that acquired with US in 28 (38%) of 74 fetuses. The additional findings were confirmed in 19 of the 28 fetuses at postnatal follow-up; no follow-up data were available for the other nine fetuses. Thoracic MR information affected care with regard to six (8%) of 74 fetuses. Mean gestational age of 15 fetuses with lung signal intensity (SI) slightly lower than that of amniotic fluid (28.4 weeks +/- 6.8 [SD]) at T2-weighted MR imaging was significantly older than that of 18 fetuses with intermediate SI (21.3 weeks +/- 4.3) (P <.05). Mean SI of 13 congenital cystic adenomatoid malformations (CCAMs) and/or sequestrations (1.74 +/- 1.05) at T2-weighted MR imaging was significantly higher than that of the normal lungs of 33 fetuses (2.63 +/-.63) (P <.001). Among nine studies in which vessels were visualized in CCAMs and/or sequestrations, six involved a normal vascular branching pattern. Portions of the esophagus were seen in 31 (36%) of 85 fetuses. Nonvisualization of a major airway was not sufficient for diagnosis of pulmonary atresia. Visualization of a portion of the esophagus did not correlate with esophageal atresia. In all except one fetus, who had anhydramnios and pulmonary hypoplasia, and the fetuses with congenital diaphragmatic hernia, at least a portion of the diaphragm was visualized at MR imaging. CONCLUSION: MR imaging yields information additional to that yielded with US in fetuses with thoracic abnormalities.     

Pelvic abnormalities in children: assessment with MR imaging

Multiplanar images of 62 pelvic lesions in 58 children and adolescents (aged 7 months to 19 years; mean, 10.6 years) were obtained with 0.3-T magnetic resonance (MR) imaging. Lesions were divided into three categories: congenital anomalies, cystic lesions and fluid collections, and neoplasms. MR demonstrated lesions well in all categories. Midline lesions were best imaged sagittally, and lesions of paired structures, axially. The coronal plane was useful in evaluating the superoinferior extent of lesions and in defining the extent of lymphadenopathy. T1-weighted sequences were sufficient to depict most congenital and cystic lesions. T2-weighted sequences were useful in demonstrating the extent of neoplasms and the position of ectopic gonads. Ultrasonography (US) was also performed in 45 cases. MR and US delineated lesions equally well in 25 cases (55.5%), MR was superior in 19 (42.4%), and US was superior in one (2.2%). Computed tomography (CT) was performed in 13 cases. MR and CT delineated lesions equally well in eight cases (61.5%), MR was superior in four (30.8%), and CT was superior in one (7.7%).     

MR imaging of cerebral abnormalities in utero

In view of the lack of ionizing radiation, ability to image in a variety of planes, and high contrast resolution, magnetic resonance (MR) imaging may have a role in obstetrical management. Three fetuses with severe cerebral abnormalities were studied by MR in utero. The findings were correlated with ultrasound examinations and with autopsy results. Ventricular dilatation and progression of hydrocephalus were detected by MR. Although fetal motion may affect image quality, diagnostically useful images were obtained with imaging times of 2.5 min.     

MR imaging of temporomandibular joint abnormalities associated with cervical hyperextension/hyperflexion (whiplash) injuries.

Patients often have temporomandibular joint (TMJ) dysfunction-related symptoms after cervical hyperextension/hyperflexion injuries ("whiplash") caused by rear-end motor-vehicle collisions. To determine abnormalities of the TMJ associated with these injuries, 33 consecutive symptomatic patients (66 joints) with no direct trauma to the jaw, mouth, head, or face due to the accident and no prior history of TMJ dysfunction underwent magnetic resonance (MR) imaging, and the images were retrospectively analyzed. Overall, 29 (88%) patients had some type of TMJ abnormality related to whiplash injury. Displacement of the disk was seen in 37 (56%) of the TMJs as follows: 21 (32%) had anterior displacement with reduction, nine (14%) had anterior displacement without reduction, six (9%) had lateral or medial displacement, and one (2%) had posterior displacement. On T2-weighted images, 43 (65%) TMJs had abnormal joint fluid or edema, predominantly affecting the joint capsule and/or lateral pterygoid muscles. The finding that many of the patients had joint fluid and/or soft-tissue edema indicates that T2-weighted images are especially useful for assessment of patients with a history of whiplash injury.     

MR imaging of abnormalities of the plantar fascia

Foot pain and disability may curtail the performance of simple routine tasks, work-related duties, and athletic activities. Disorders of the plantar fascia are commonly encountered in the diagnostic evaluation of subcalcaneal heel pain. The approach to imaging the ankle and foot has undergone significant amendment with the introduction of magnetic resonance (MR) imaging. MR imaging allows direct visualization of the plantar fascia and permits a comprehensive evaluation of a wide spectrum of disorders involving the fascia and perifascial structures, including bones, ligaments, musculotendinous units, and intrinsic muscles of the foot. The objectives of our cadaveric and clinical study are to describe the normal MR imaging appearance of the plantar fascia and analyze the signal intensity changes in the fascia and perifascial tissue with conventional MR imaging in symptomatic patients. We present a brief overview of common disease processes involving the plantar fascia that may prove practical for routine imaging evaluation of patients with suspected pathology.     

CT and MR imaging findings associated with subacute thyroiditis

Subacute granulomatous thyroiditis is an uncommon disease that occurs most often in women in their second to fifth decades of life. This disease usually presents with thyroid tenderness, a low grade fever, and occasional dysphagia. The disease resolves spontaneously, usually without thyroid function abnormalities. We herein present the CT and MR imaging findings of two cases of subacute granulomatous thyroiditis.     

CT and MR findings in diastematomyelia, with embryogenetic consideration.

Diastemstomyelia is an extremely rare disorder that is seldom found among the Japanese. This paper presents two Japanese patients, a newborn male and a newborn female, with diastematomyelia. CT demonstrated bony spurs more clearly than plain film, and magnetic resonance images indicated split cords and associated anomalies. Although the embryogenesis of diastematomyelia has not been clearly elucidated, the coincidence of levels of associated anomalies and diastematomyelia in our cases and in the literature supports Bremer's embryogenetic explanation of persistent accessory neurenteric canal.     

Anterior tibial tendon abnormalities: MR imaging findings

PURPOSE: To retrospectively evaluate the magnetic resonance (MR) imaging findings of anterior tibial tendon (ATT) abnormalities. MATERIALS AND METHODS: Institutional review board approval was not necessary for review of patient images and was granted for examination of the volunteers; informed consent was obtained. MR imaging findings in 28 consecutive patients (20 women, eight men; mean age, 63.2 years) clinically suspected of having an ATT abnormality were compared with those in an age- and sex-matched control group of 28 asymptomatic volunteers (20 women, eight men; mean age, 62.9 years). Surgical correlation was available for 11 patients. The short-axis diameter of the ATT and the longitudinal extent of signal intensity abnormalities were measured (Mann-Whitney U test). Signal intensity abnormalities of the ATT and irregularities of the underlying tarsal bones were analyzed in consensus by two blinded radiologists (chi2 test). RESULTS: In the symptomatic group, three cases of tendinosis and 13 partial and 12 complete ATT tears were diagnosed. In 11 cases (one case of tendinosis and two cases of partial and eight cases of complete ATT tear), surgical correlation was available and the MR imaging diagnosis was confirmed. In the asymptomatic group, four cases of tendinosis of the ATT were seen. The ATT diameter was significantly thicker in symptomatic patients at 1 cm (5.1 vs 3.1 mm in control group, P < .001), 3 cm (5.8 vs 3.4 mm, P < .001), and 6 cm (5.4 vs 4.3 mm, P = .006) proximal to the distal point of insertion. Most ATT abnormalities (in 23 [82%] of 28 patients) were located within the first 3 cm proximal to the insertion. Signal intensity abnormalities were seen in the anterior portion of the ATT in two (7%) of the 28 symptomatic patients and in the posterior portion in 11 (39%); diffuse involvement was seen in 15 (54%). Bone spurs on the navicular surface (nine [32%] patients vs no [0%] control subjects, P = .001), a ridged shape of the medial surface of the medial cuneiform bone (13 [46%] vs one [4%], P < .001), and osteophyte formation at the first tarsometasarsal joint (eight [29%] vs two [7%], P = .036) were significantly more common in the symptomatic patient group. CONCLUSION: Characteristic findings of ATT abnormalities include tendon thickening (> or =5 mm) and diffuse or posterior signal intensity abnormalities of the tendon within 3 cm from the distal point of insertion.     

Diffusion MR imaging changes associated with Wilson disease

We herein report the case of a patient with Wilson disease. The patient underwent echo-planar diffusion MR imaging twice, 1.5 years apart. The lesions were in the putamina and caudate nuclei. At the first examination, undertaken after onset of extrapyramidal symptoms, a restricted diffusion pattern was evident. It is likely that this corresponded to cell swelling caused by the accumulation of copper. On the images obtained 1.5 years later, an opposite pattern (an elevated diffusion pattern) was noted. It is likely that this reflected necrosis, spongiform degeneration, and demyelination, which are among the known histopathologic changes associated with Wilson disease.