MRI of childhood dacryocystocele

We report an unusual presentation of a dacryocystocele in a 3-day-old child, with clinical and novel MRI findings. The literature contains extensive CT documentation, but descriptions of the MRI appearances of dacryocystoceles are lacking. Although CT is the standard initial imaging modality, MRI can be helpful if there are questions as to the content of the lesion or a need for further anatomical characterization.

Intracranial giant cell reparative granuloma arising from the temporal lobe area: MR findings

SUMMARY

We present an unusual case of a giant cell reparative granuloma arising from the left temporal lobe area of a 38-year-old man and provide clinical and MR findings. Current diagnosis and treatment options are also discussed.

Clinical studies of families with hearing loss attributable to mutations in the connexin 26 gene (GJB2/DFNB1)

OBJECTIVE

This retrospective study describes the phenotype associated with the single most common cause of genetic hearing loss. The frequency of childhood deafness is estimated at 1/500. Half of this hearing loss is genetic and approximately 80% of genetic hearing loss is nonsyndromic and inherited in an autosomal recessive manner. Approximately 50% of childhood nonsyndromic recessive hearing loss is caused by mutations in the connexin 26 (Cx26) gene (GJB2/DFNB1), making it the most common form of autosomal recessive nonsyndromic hearing loss with a carrier rate estimated to be as high as 2.8%. One mutation, 35delG, accounts for approximately 75% to 80% of mutations at this gene.

METHODS

Hearing loss was examined in 46 individuals from 24 families who were either homozygous or compound heterozygous for Cx26 mutations. A subset of these individuals were examined for vestibular function, otoacoustic emissions, auditory brainstem response, temporal bone computed tomography, electrocardiography, urinalyses, dysmorphology, and thyroid function.

RESULTS

Although all persons had hearing impairment, no consistent audiologic phenotype was observed. Hearing loss varied from mild-moderate to profound, even within the group of families homozygous for the common mutation 35delG, suggesting that other factors modify the phenotypic effects of mutations in Cx26. Furthermore, the hearing loss was observed to be progressive in a number of cases. No associations with inner ear abnormality, thyroid dysfunction, heart conduction defect, urinalyses, dysmorphic features, or retinal abnormality were noted.

CONCLUSION

Newborns with confirmed hearing loss should have Cx26 testing. Cx26 testing will help define a group in which approximately 60% will have profound or severe-profound hearing loss and require aggressive language intervention (many of these patients will be candidates for cochlear implants).

Verification of lumbosacral segments on MR images: identification of transitional vertebrae

To accurately identify lumbosacral transitional vertebrae and disease location, cervicothoracic sagittal scout images were obtained in addition to the standard images used in magnetic resonance imaging studies of the lumbar spine, and vertebrae were counted down from C-2 rather than up from L-5. In 200 patients, these techniques revealed 24 transitional vertebrae (15 cases of sacralization of L-5 and nine cases of lumbarization of S-1).

Increased intracranial pressure as a complication of unilateral radical neck dissection in a patient with congenital absence of the transverse sinus

We report a patient with increased intracranial pressure occurring after unilateral neck dissection. Subsequent vascular studies reveal a hypoplastic contralateral transverse sinus drainage and occlusion of the ipsilateral jugular bulb. We review the literature on the etiology of this vascular malformation and conclude that vascular anomalies of the venous drainage of the head be considered whenever postoperative signs of increased intracranial pressure occur after unilateral radical neck dissection.

Axial herniation with brain stem deformity as a cause of sleep apnea

A patient with an intracerebral hematoma and associated edema in the high right hemisphere parasagittal convexity had several episodes of apnea at night and during the day when she was asleep. On computed tomography (CT) scan, the hematoma demonstrated no evidence of brainstem compression. Sagittal magnetic resonance image (MRI), revealed the hematoma and edema mass resulted in central herniation with axial deformity of the brainstem. This is believed to be the cause of the apneic episodes. Treatment with mannitol and steroids promptly relieved the symptom.

Percutaneous discectomy using the electromagnetic field focusing probe. A feasibility study

The EFF probe has the capability of sharply focusing the eddy currents produced in tissue secondary to the electromagnetic field it generates. This sharp convergence of eddy current produces intense heat at the point of contact of the probe to the tissue, which can vaporize tissue. The probe diameter can be as small as required which makes it easy to be navigated into disc space for disc vaporization. Four discs were vaporized in three pigs by inserting the probe into the disc and vaporizing it. The vertebral columns were removed and transverse sections through the disc were made. Excellent disc vaporization was observed with vaporization of 70-80% of the nucleus. As the probe can be of flexible material it could be turned in different directions to vaporize necessary disc material.

Magnetic resonance imaging of the brain in infants and children before and after cardiac surgery. A prospective study

We assessed the morphologic findings of the brain prospectively before and after cardiac surgery using magnetic resonance imaging. There were 12 patients with acyanotic and 6 with cyanotic heart disease. There were 2 deaths, and 1 patient did not have to undergo postoperative magnetic resonance imaging. The study group consisted of 15 patients completing both the preoperative and postoperative magnetic resonance imagings. All patients in the study group underwent moderate hypothermic cardiopulmonary bypass using a nonpulsatile membrane oxygenator. The mean (+/- SD) cardiopulmonary bypass time was 100 +/- 55 minutes. Ten of the preoperative studies were interpreted as normal. One third (5 of 15) of the patients showed ventriculomegaly and dilatation of the subarachnoid spaces on preoperative magnetic resonance images. Measurements of the preoperative and postoperative magnetic resonance images showed a postoperative increase in the bicaudate and third ventricular diameters. Four patients in the study group developed postoperative subdural hematomas. The subdural hematomas were small and caused no demonstrable mass effect on magnetic resonance imaging. One patient had a preoperative white matter infarction. There was 1 patient with a postoperative infarction.

Magnetic resonance imaging of degenerative disk disease of the spine

MRI has undergone an incredibly rapid evolution, and technical advances are continually occurring. MRI allows for high resolution imaging that can clearly demonstrate a variety of degenerative processes of the spine. High-resolution MRI that gives detailed anatomic information, coupled with the use of MR contrast agents, promises to change our diagnostic approach significantly for degenerative disk disease of the spine.

Artifacts and diagnostic pitfalls on magnetic resonance imaging: a clinical review

High field MRI of the brain occasionally exhibits imaging artifacts; most artifacts are obvious and easily recognized, but some are subtle and mimic disease. A thorough understanding of brain MRI artifacts is important to avoid potential diagnostic pitfalls. Some imaging techniques or procedures could be utilized to remove or identify artifacts. These include additional projections, different pulse sequence, and 90 degree shift of phase-encoding gradient. The use of respiratory gating or cardiac gating may also improve image quality by reducing some of the motion-related artifacts.

The MR appearance of hypothalamic hamartoma

Hypothalamic hamartoma is the most common detectable cerebral lesion causing precocious puberty. Two histologically confirmed cases were studied by computerized tomography (CT) and magnetic resonance (MR) imaging. T2 weighted, sagittal MR images were superior to CT in delineating the tumor from surrounding grey matter. The lesion was isointense to grey matter on T1 weighted images allowing exclusion of other hypothalamic tumors. MR will undoubtedly become the imaging modality of choice in the detection of hypothalamic hamartoma.

Cerebellar hemangioblastoma with prominent stromal astrocytosis: diagnostic and histogenetic considerations

A cerebellar hemangioblastoma with atypical radiologic and morphologic features is reported. On computed tomography this tumor presented as a single ring-enhancing mass in the right cerebellar hemisphere without adjacent cyst formation. It was radiologically indistinguishable from an abscess or malignant neoplasm. Postmortem examination demonstrated a circumscribed, cystic neoplasm arising in the pia at the base of a sulcus. Microscopically, the tumor contained a prominent astrocytic component that mimicked the appearance of a highly vascular astrocytoma. Hemangioblastomas with this degree of astrocytosis are unusual. They must be distinguished pathologically from both cystic astrocytoma and mixed hemangioblastoma-glioma (angioglioma).

Loculated abscesses: management by percutaneous fracture of septations

Large, multiloculated abscesses can be difficult to drain percutaneously. The authors describe a technique for disrupting septations within an abscess cavity to provide more complete and effective drainage. It has been successfully performed in four patients.

Peripheral signal void ring in giant vertebral aneurysm: MR and pathology findings

Thin, signal void rims have been noted to surround intracerebral hemorrhages and ruptured intracranial aneurysms on magnetic resonance imaging. Proposed mechanisms include hemosiderin deposition in macrophages and high blood flow. The authors describe an example of a thick, signal void ring in a peripheral luminal thrombus of a giant vertebral aneurysm.

A new method for treatment of unresectable, recurrent brain tumors with single permanent high-activity 125iodine brachytherapy

We describe a new method for treating unresectable recurrent brain tumors in previously-irradiated patients with localized high-dose intracranial brachytherapy of 10,000-30,000 rads using permanent implantation of a single high-activity 125Iodine seed. For unresectable recurrent previously-irradiated pituitary tumors, a single high-activity 125Iodine seed is permanently implanted into the center of the tumor with an interstitial needle inserted under fluoroscopic guidance via a transsphenoidal approach. For unresectable recurrent meningiomas, a single high-activity seed is permanently implanted into the tumor at craniotomy. The clinical course of five patients treated by this method is described. Excellent long-term local control was obtained in all implanted cases. There were no intraoperative, postoperative, or chronic complications.

Ocular volume measured by CT scans

Newer CT scans have greatly enhanced oculometric research and made it possible to measure ocular dimensions. With these measurements, ocular volume can be more accurately estimated to understand its relationship with age and sex. One hundred CT orbit scans with presumed normal eyes were used for the data base. The mean values and normal variations of ocular volumes at various ages in both sexes are presented. Rapid growth of the eyeball was noted during the first 24 months of age. It reached its peak between the ages of 18 and 30 years of age, after which there was a reduction. Results may be of help in recognizing eye abnormalities such as microophthalmus and macrophthalmia.

CT measurements of cranial growth: normal subjects

Growth patterns of the cranium measured directly as head circumference have been well documented. With the availability of computed tomography (CT), cranial dimensions can be obtained easily. The objective of this project was to establish the mean values and their normal variance of CT cranial area of subjects at different ages. Cranial areas and its long and short axes were measured on CT scans for 215 neurologic patients of a wide age range who presented no evidence of abnormal growth of head size. Growth patterns of the cranial area as well as the numeric product of its linear dimensions were determined via a curve fitting process. The patterns resemble that of the head circumference growth chart, with the most rapid growth observed in the first 12 months of age and reaching full size during adolescence. It is believed that the availability of such reference, in addition to the head circumference measurement, will be valuable to the CT reviewer in determining the growth status of head size.

CT measurements of cranial growth: microcephaly

Computed tomographic (CT) head scans were measured to determine the cranial dimensions of four children with microcephaly. These measurements were compared with cranial dimensions of normal children. CT proved to be useful in determining the developmental status of children with neurologic problems relative to their normal counterparts on the basis of cranial dimensions.

Aneurysms of the posterior cerebral artery in children

Intracranial aneurysms in children are very rare and differ from those in adults in several ways. Posterior cerebral artery (PCA) aneurysms are among the least common of intracranial aneurysms and little is known of their presentation and prognosis. Two cases of PCA aneurysms in children are reported, and 21 other cases of PCA aneurysms in patients 20 years of age or younger are reviewed. PCA aneurysms in children have a marked male predominance and are usually large, symptomatic, and tend to occur proximal or distal to the circle of Willis. Diagnostic computed tomography may be warranted earlier in children than in adults with similar symptoms referable to intracranial abnormalities because children are more likely to have an organic cause for such symptoms.

The overshoot artifact as an aid in differentiating low densities on the computed tomographic scan

This brief report describes an artifact that is seen as a thin, white rim outlining an air collection on the EMI 80 X 80 and 160 X 160 matrix CT scanners. This artifact is not associated with fat density and, therefore, its recognition allows presumptive differentiation between air and fat densities. The attenuation numbers of the lesion should then be obtained for confirmation.

Computed tomography in cerebral hemiatrophy

The clinical and radiographic findings in four cases of cerebral hemiatrophy are presented. CT findings reflect the underlying gross pathologic changes and are in agreement with those seen on plain skull radiography and pneumoencephalography. The most impressive finding was unilateral loss of cerebral volume with ipsilateral displacement of the midline structures. The differential diagnosis primarily includes Sturge-Weber syndrome and linear sebaceous nevus syndrome. The recognition of compensatory calvarial changes should indicate that the cerebral abnormalities are the result of an atrophic or hypoplastic process that began in early life.

Renal lymphoma simulating adult polycystic disease

Multiple cyst-like involvement of the kidney in a patient with lymphocytic lymphoma is presented. Both kidneys demonstrated the swiss-cheese appearance on nephrograms, simulating a typical adult type of polycystic disease. No tumor vessels or strains were noted.

Thromboembolic complications of angiography for peripheral arterial disease: prospective assessment by Doppler ultrasound

The incidence of thromboembolic arterial complications related to percutaneous angiography done for patients with arterial disease was assessed in 101 cases (105 procedures). There were 2 instances of anterior tibial artery obstruction and 3 of a decline in ankle pressure greater than 20 mmHg in patients with preexisting leg arterial disease. No patient evidenced symptoms of the complications. This incidence of thromboembolic accident, detected by Doppler ultrasound, is significantly less than those incidence rates noted previously, although the reasons for this difference have not yet been established.

Scintigraphic findings in hyperostosis frontalis interna

Transient diminution of activity was seen on early radionuclide images of the brain in 5 patients with hyperostosis frontalis interna and filled in on subsequent studies. Radiographs confirmed the diagnosis. In 3 patients the changes corresponded extremely well with both modalities. This entity should be considered when diminished activity is seen in the frontal area.

Frontal ventricular dimensions on normal computed tomography

The computerized axial tomographic examinations of 200 normal patients and volunteers between the ages of ten to 81 years were evaluated. Determination of the ratio between the width of the brain and a dimension representing the distance between the outer borders of the lateral ventricles was made at two levels. This ratio, the cerebroventricular index, seems to be a reliable indicator of ventricular size. The standards vary with the age of the patient.

The excessively small ventricle on computed axial tomography of the brain

Computed axial tomography has made it possible to observe excessively small ventricles in a variety of disorders of the CNS. This finding is presumably due to non-specific and diffuse swelling of brain parenchyma, and is illustrated in cases of trauma, neoplasm, encephalitis, pseudotumor cerebri, metabolic disorder, and probable dilantin effect. It is likely that other causes will be encountered in the future.

Brain image manifestation in the patient with cavernous sinus occlusion

Radionuclide findings in a case of cavernous sinus occlusion by an intracavernous aneurysm are described. A brain image obtained 10 minutes after injection of 99Tc pertechnetate shows diminished activity in the area of the right cavernous sinus and increased activity in the area of the right sylvian veins; these are attributed to abnormal venous blood flow and may serve as a sign of cavernous sinus occlusion.