High strength MRI-Adverse Effects

Biologic Effects of 3 Tesla (T) MR Imaging Comparing Traditional 1.5 T and 0.6 T in 1023 Consecutive Outpatients. J Neuroimaging 2007 Jul;17(3):241-5. Weintraub MI, Khoury A, Cole SP.

" The recent use of high and ultra-high magnetic field (MF) systems (3.0 T and above) have raised concerns about biologic effects and safety. Sensory symptoms (magnetophosphenes, dizziness/vertigo, headaches, metallic taste, pain changes, and cognitive effects) have been reported. According to the authors-- New onset symptoms occurred predominantly with 3 T and female preponderance. Vertigo/dizziness , headache, spine pain occurred more frequently on 3 T, whereas magnetophosphenes and metallic mouth symptoms occurred principally in 1.5 T. Symptoms of vertigo/dizziness, headaches, and magnetophosphenes were more commonly seen in individuals undergoing brain MRIs but other body sites were also represented. Although no harmful effects, an unexpected high rate of 14% of individuals experienced sensory stimulation in both 3 T and 1.5 T units. Females appear to be more magnetically sensitive."

Graves ophthalmopathy

Findings

Figure 1: Axial CT-There is symmetrical proptosis on both sides. There is marked homogeneous enlargement of the muscle bellies of the extraocular muscles.
Figure 2: Coronal CT- Demonstrates enlargement of multiple muscles within the orbits bilaterally, with relative sparing of the lateral recti muscles.
Figure 3: Sagittal CT- There is crowding at the orbital apex with straightening of the optic nerve.
Figure 4: Axial postcontrast MRI – Homogeneous enhancement of the enlarged muscle bellies. There is marked bending of the lamina papyracea secondary to marked enlargement of medial recti muscles on both sides.


Diagnosis: Thyroid associated orbitopathy (Graves ophthalmopathy)


Thyroid associated orbitopathy (TAO), frequently termed Graves ophthalmopathy, is an autoimmune orbital inflammatory condition that is strongly associated with dysthyroidism. The lymphocyte-mediated inflammatory process affects the extraocular muscles, periorbital fat and connective tissues.

The eye findings associated with Graves disease can occur before, during, or long after the thyroid disease has been discovered or treated. While the orbitopathy is most commonly associated with hyperthyroid states, it can be seen in euthyroid and even hypothyroid patients.

It is associated with:
1) Graves hyperthyroidism (80%);
2) Hashimoto's thyroiditis (10% to 15%); or
3) unclassified thyroid immunologic abnormality (5%).

Thyroid associated orbitopathy usually affects young and middle-aged adults, females being affected 3 to 6 times more commonly than males. It may result in eyelid retraction, proptosis, chemosis, periorbital edema, and altered ocular motility with vision-threatening exposure keratopathy, troublesome diplopia, and compressive optic neuropathy occurring in untreated cases. TAO usually has a self-limited course, but significant chronic orbitopathy may occur in 10% to 15% of cases. Stable TAO can occasionally reactivate, but this is uncommon.

Orbital involvement is bilateral in 90% cases, although it may be asymmetric and symptoms may be unilateral. There is bilateral enlargement of extraocular muscles with increased orbital fat resulting in exophthalmos. The inferior and medial recti muscles are first to be involved. The lateral rectus muscle is the last to be involved and rarely shows isolated involvement. Muscle enlargement characteristically involves the belly, sparing the tendinous attachment to the globe.

Lacrimal gland enlargement may be seen. CT and MRI may also show “stretching” and apical crowding of the optic nerve with an enlarged superior ophthalmic vein.

TAO usually has a self limited course with favorable outcome. In approximately 10% of cases further therapy is required, such as systemic glucocorticoids or orbital radiotherapy. Surgical orbital decompression is reserved for those patients in which vision is threatened, where there is the presence of severe cosmetic deformity, or failure of medical management.

Freiberg Infarction-Case Report

"Points to remember-infarction because it is supposed to be trauma realted common in adolescents comes with pain women more than men.usually conservative management will do. Surgery is the option for non responders.D/D will be osteomyelitis in this joint gets involved usually proximal phalanx may be involved too.
Case submitted by Dr (Col) MGK Murthy & Dr David Kiran,Consultant Teleradiology Providers

Joubert syndrome

Findings

There is elevation of the fourth ventricle and hypoplasia of the superior portion of the vermis. There is thickening of the superior cerebellar peduncles bilaterally. These form a characteristic "molar tooth" sign as seen on axial images.


Diagnosis: Joubert syndrome


Key points

The syndrome was first described by Joubert and colleagues as a familial agenesis of the cerebellar vermis and appears to be inherited as an autosomal recessive trait. Both sexes are affected and the onset is in early infancy. Its incidence is unknown. Most patients die in infancy or early childhood. The predominant abnormality in Joubert's syndrome is aplasia or hypoplasia of the vermis, particularly the superior portion. In addition, these patients have heterotopic and dysplastic cerebellar tissue, abnormal development of the inferior olivary nuclei, and incomplete formation of the pyramidal decussation.


Clinical diagnosis

The most common features of Joubert's syndrome in infants include hyperpnea, jerky eye movements, and ataxia. The facial appearance in patients with Joubert syndrome may be near-normal, or may include high, rounded eyebrows, broadening of the nasal bridge, and mild epicanthus. The nares may be anteverted, and the mouth triangularly shaped.

Some patients with Joubert syndrome are severely affected, dying in infancy. The vast majority (> 90%) of surviving patients with Joubert syndrome are below chronological age in cognitive and motor development, although in a few patients, cognition may appear near-normal. CNS anomalies reported with Joubert's syndrome include callosal dysgenesis, congenital retinal dystrophy, and oculomotor abnormalities. Non-CNS disorders include neonatal breathing abnormalities, polydactyly, and cystic kidney disease.


Radiologic overview

Sagittal T1W images demonstrate a diminutive vermis. Axial images in particular show an enlarged fourth ventricle that is "bat-wing shaped" in configuration. The superior cerebellar peduncles are vertically oriented and elongated in the anteroposterior direction. Because of the dysgenesis of the vermis, the hallmark of Joubert's syndrome is separation or disconnection of the cerebellar hemispheres, which are apposed but not fused in the midline. The midbrain is small in its anteroposterior diameter, probably because of the absence of the decussation of the superior cerebellar peduncles. The characteristic appearance of the midbrain, with the enlarged superior cerebellar peduncles and the absence of their decussation has been called the "molar tooth sign". Associated supratentorial anomalies are uncommon, but cerebral cortical dysplasia and gray matter heterotopia have been reported.


Management and treatment

The prognosis for infants with Joubert's syndrome depends on whether or not the cerebellar vermis is entirely absent or partially developed. Some children have a mild form of the disorder, with minimal motor disability and good mental development, while others may have severe motor disability and moderate mental retardation. Treatment for Joubert syndrome is symptomatic and supportive. Infant stimulation and physical, occupational, and speech therapy may benefit some children. Infants with abnormal breathing patterns should be monitored.

Ependymal cyst

Findings

Figure 1: Axial T1 weighted image shows a large well defined homogenous mass in the right lateral ventricle which is isointense with CSF and arises from the atrium and measures 8.8 cm by 4.2 cm by 6.0 cm. There is dilatation of the right occipital horn and midline shift to the contralateral side indicating mass effect.
Figure 2: Axial T2 weighted image demonstrates that the mass is again isointense with CSF, indicative of cyst. The thin regular cyst wall is visualized. There is no edema in the adjacent brain parenchyma.
Figure 3: Diffusion-weighted image illustrates no evidence of restricted diffusion. The fluid within the cyst has the same diffusion characteristics as CSF.
Figure 4: Axial T1 weighted postgadolinium image shows no abnormal enhancement. Note the compressed vasculature adjacent to the cyst.
Figure 5: Coronal T1 weighted post gadolinium image depicts the large cyst in the right lateral ventricle.


Diagnosis: Ependymal cyst


Ependymal cysts are rare intracranial lesions that are found in the brain parenchyma, ventricles, and subarachnoid space. The cysts are most often juxtaventricular in location within the brain parenchyma involving the frontal or temporal lobes. They are less often found within the ventricles with the lateral ventricles being the most common. Subarachnoid ependymal cysts are extremely rare. The origin of the cysts is unknown, but they are thought to originate from invagination of neuroectoderm, and the cysts are lined with either cuboid or columnar epithelium.

Ependymal cysts are typically found in young males in their 30s and 40s. The cysts are usually asymptomatic and are incidental imaging findings, but when symptomatic, patients will present with headache, seizures, or dementia. On CT imaging, the thin cyst wall may not be visible, and the cystic fluid is of the same density as CSF. There is no enhancement following contrast administration. On MR imaging, the cystic fluid will be isointense to CSF on all pulse sequences. Sometimes the cyst may have a proteinacous content, due to mucinous secretion by the epithelial cells that line the cyst, which is represented by an increase in signal intensity best seen on FLAIR images. The cyst wall is often visible on MR, but its absence does not exclude the diagnosis. The cyst will not show restricted diffusion, and similar to CT, there will be no enhancement following contrast administration. Ependymal cysts of widely variable sizes have been reported, and large cysts may obstruct CSF flow and cause hydrocephalus.

Prognosis for ependymal cysts is excellent. Since most cysts are asymptomatic, patients can be followed conservatively. Cysts that are symptomatic require either surgical decompression or excision. Recurrence after surgical excision is rare.

The patient in this case is particularly interesting due to his extremely young age and symptomatic presentation. He was managed surgically with placement of a cystoperitoneal shunt catheter and has been seizure free since his hospital discharge.

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One Stop Urinary Tract Imaging

In Abdom Imaging. 2007 Feb 14, Dillman JR et al discuss the role of and various indications, specific techniques, image reconstruction/reformatting, detection of pathology, and pitfalls related to CTU. Article is entitled "Multi-detector CT urography: a one-stop renal and urinary tract imaging modality."

According to them-"Multi-detector computed tomography urography (CTU) is a robust imaging modality for evaluation of the kidneys and urinary tract. When compared to excretory urography (EU), CTU's superior contrast resolution appears to more effectively detect and characterize numerous benign and malignant conditions involving the kidneys, upper urinary tracts, and urinary bladder. "