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Biomedical subjects

G L Hedlund

Publications and source records attributed to G L Hedlund.

At least 19 recordsLinked to original sources
PubMed2006

Absent semicircular canals in CHARGE syndrome: radiologic spectrum of findings.

BACKGROUND AND PURPOSE: This paper describes the CT findings that characterize the middle and inner ear anomalies in coloboma, heart defects, choanal atresia, mental retardation, genitourinary, and ear anomalies (CHARGE) syndrome. With this information, neuroradiologists will be better prepared to provide clinically relevant information to their referring physicians regarding this rare syndrome. MATERIALS AND METHODS: CT studies from 13 patients were reviewed by 2 neuroradiologists with Certificate of Additional Qualification. Each ear was counted separately for a total of 26 ears. Middle and inner ear anomalies associated with CHARGE syndrome were categorized. Investigational review board approval was obtained. RESULTS: Twenty of 26 (77%) ears demonstrated cochlear aperture atresia. Four of these ears were evaluated with MR imaging and were found to lack a cochlear nerve. Twenty-one of 26 (81%) cochlea had some form of dysplasia. Six of 26 (23%) round windows were aplastic. Three of 26 (12%) round windows were hypoplastic. Twenty-one of 26 (81%) oval windows were atretic or aplastic. Fifteen of 26 (58%) vestibules were hypoplastic or dysplastic. There were 5 of 26 (19%) enlarged vestibular aqueducts. Twelve of 26 (46%) vestibular aqueducts had an anomalous course. All cases demonstrated absent semicircular canals. Twenty-three of 26 (88%) facial nerve canals had an anomalous course. Four of 26 (15%) tympanic segments were prolapsed. Three of 26 (12%) temporal bones had an anomalous emissary vein referred to as a petrosquamosal sinus. Twenty-one of 26 (81%) middle ear cavities were small. Twenty-three of 26 (93%) ossicles were dysplastic with ankylosis. Three of 26 (12%) internal auditory canals were small. CONCLUSION: The CT findings that correlate to the anomalies of CHARGE syndrome affect conductive as well as sensorineural hearing. Stenosis of the aperture for the cochlear nerve aperture on CT is suggestive of hypoplasia or absence of the cochlear nerve, which has been demonstrated in some cases by MR. Absence of the cochlear nerve would be a contraindication to cochlear implantation.

Abnormalities, Multiple↗
PubMed2000

Enlarged parietal foramina: association with cerebral venous and cortical anomalies.

OBJECTIVE: To evaluate a series of patients with enlarged parietal foramina for associated brain anomalies. BACKGROUND: Enlarged parietal foramina are usually considered a benign calvarial defect. METHODS: Ten patients with enlarged parietal foramina were identified. Seven patients were evaluated with neuroimaging: two by cranial CT and five by CT and/or MRI. Three patients who underwent MRI also underwent MR angiography or MR venography. RESULTS: Six of seven patients had cranial imaging showing a persistent falcine venous sinus. Three of six patients had variations of occipital cortical infolding. One patient had focal encephalomalacia in close proximity to the persistent falcine venous sinus and one had a previously undiagnosed atretic occipital encephalocele. CONCLUSION: This constellation of findings suggests that aberrant vascular evolution during fetal development may affect cerebrovascular, brain, or skull development. Individuals with enlarged parietal foramina (>5 mm) warrant imaging of underlying brain parenchyma and vasculature.

Adult↗
PubMed2000

CT, MRI and MRS of Epstein-Barr virus infection: case report.

We report MRI and proton MR spectroscopy (MRS) findings in a 12-month-old girl with Epstein-Barr virus encephalitis. CT and MRI showed focal lesions in the basal ganglia. MRS of the lesions showed decreased N-acetyl aspartate and elevation of some amino acids, indicating an infectious rather than ischemic etiology. This case illustrates the use of MRS to narrow differential diagnosis.

Encephalitis, Viral↗
PubMed1999

Aggressive manifestations of inflammatory pulmonary pseudotumor in children.

We present three cases that illustrate the locally invasive radiographic appearance that inflammatory pulmonary pseudotumor can assume. Awareness and inclusion of inflammatory pseudotumor in the differential diagnosis of aggressive pleuropulmonary and mediastinal processes may have critical treatment implications.

Anastomosis, Surgical↗
PubMed1999

MRI diagnosis of suspected atlanto-occipital dissociation in childhood.

OBJECTIVE: To demonstrate the utility of magnetic resonance (MR) imaging in the diagnosis of complete and partial ligamentous injuries in patients with suspected atlanto-occipital dissociation (AOD). MATERIALS AND METHODS: Five patients with suspected AOD had MR imaging performed within an average of 4 days after injury. MR scans were reviewed with specific analysis of craniocervical ligamentous structures. Charts were reviewed to obtain clinical information regarding presentation, treatment, hospital course, and outcome. RESULTS: Two patients demonstrated MR evidence of complete AOD. One had disruption of all visualized major ligamentous structures at the craniocervical junction with anterolisthesis and evidence of cord damage. The second had injuries to the tectorial membrane, superior band of the cruciform ligament, apical ligament, and interspinous ligament at C 1-2. The remaining three patients sustained incomplete severance of the ligamentous structures at the craniocervical junction. All patients demonstrated subtle radiographic findings suggestive of AOD, including soft tissue swelling at the craniocervical junction without fracture. The two patients with complete AOD died. The three patients with partial AOD were treated with stabilization. On follow-up, these three children were asymptomatic following their craniocervical injury. CONCLUSION: MR imaging of acute AOD provides accurate identification of the craniocervical ligaments injured, classification of full versus partial ligamentous disruption, and analysis of accompanying spinal cord injury. This information is important for early appropriate neurosurgical management and preservation of neurologic function in survivors.

Atlanto-Occipital Joint↗
PubMed1999

Neuroimaging of postnatal pediatric central nervous system infections.

Pediatric neuroimaging plays an important role in the timely diagnosis of postnatal central nervous system (CNS) infections, and in some patients the imaging findings are sufficiently specific to suggest a cause. The sequela of CNS infection, including hydrocephalus, subdural collections, ischemia/infarction, cerebral abscess, demyelination, and vascular thrombosis, can be accurately depicted and serially followed with current imaging techniques. The purpose of this review is to describe the spectrum of pediatric postnatal CNS infections, emphasizing key pathological and neuroimaging features, and to outline the strengths, weaknesses, and applications of current neuroimaging technology. The prenatal and perinatal infections falling under the designation of TORCH (toxoplasmosis, other [e.g., syphilis, HIV], rubella, cytomegalovirus, and herpes simplex II) are not covered.

Brain↗
PubMed1998

Peritoneal metastases in children with cancer.

BACKGROUND: This study attempted to evaluate the childhood malignancies associated with computed tomography (CT) detected peritoneal metastases as well as the diagnostic imaging characteristics of these metastases as shown on CT. METHODS: The authors reviewed all available pathology specimens and abdominopelvic CT scans of patients identified as having peritoneal metastases at three childhood cancer centers. Patient demographics, primary diagnosis, and CT characteristics of such metastases were evaluated. RESULTS: Peritoneal metastases were identified by CT in 32 children with cancer either at diagnosis (n = 20) or up to 6.2 years from diagnosis (n = 12). On CT, peritoneal disease appeared as a mass in 26 cases, as studding in 11 cases, as peritoneal enhancement in 15 cases, and as diffuse caking in 4 cases (15 patients had > 1 category of peritoneal metastasis). Thirteen patients had concurrent metastases in other sites. Fourteen patients died of progressive disease at a median of 10 months from the time peritoneal metastases were identified on CT. At last follow-up, the remaining 18 patients were alive, with follow-up ranging from 1 month to 9.7 years. As expected, peritoneal metastases were identified in patients with germ cell tumors and colon carcinoma. However, they also were observed in patients with epithelioid carcinoma, leiomyosarcoma, pineoblastoma, neuroblastoma, melanoma, and peripheral neuroectodermal tumor. CONCLUSIONS: Peritoneal metastases have variable appearance on CT, but most commonly appear mass-like. They are associated with a wider range of primary diagnoses than reported previously. The outcome varies with the type of the primary tumor and its responsiveness to existing therapies.

Adolescent↗
PubMed1998

The resolution of syringohydromyelia without hindbrain herniation after posterior fossa decompression.

OBJECT: To provide more information about this rare condition, the authors describe five cases of syringohydromyelia without hindbrain herniation. Preoperative magnetic resonance imaging with and without gadolinium-diethylenetriamine pentaacetic acid revealed no evidence of spinal cord tumor, arachnoiditis, or spinal dysraphism. METHODS: Craniocervical decompression was performed in all patients, after which there was resolution of the symptoms in the four symptomatic patients, and all five showed marked reduction in the size of the syrinx. CONCLUSIONS: The authors hypothesize the rare occurrence of syringohydromyelia resulting from a Chiari-like pathophysiological condition but lacking a hindbrain hernia. Patients with this condition may benefit from craniocervical decompression.

Adolescent↗
PubMed1994

Disorders of puberty: a practical imaging approach.

The child presenting with abnormal pubertal development elicits great parental concern and presents a diagnostic challenge to the managing pediatrician. The appropriate workup of children with disorders of pubertal development relies heavily on the synthesis of history, physical examination, pertinent laboratory tests, and medical imaging. This review addresses female and male disturbances in pubertal development and includes isosexual and heterosexual precocious puberty and delayed development. Discussion is focussed on the tailored algorithmic approach to imaging; integrating clinical and laboratory information. Bone-age determination, ultrasonography, and MRI are emphasized as they relate to this complex and challenging clinical problem.

Adolescent↗
PubMed1991

Air enema for diagnosis and reduction of intussusception: clinical experience and pressure correlates.

Air enema was used for exclusion, diagnosis, initial movement, and complete reduction of intussusception in 186 pediatric patients. Average pressure needed for initial movement of intussusception was 56.5 mm Hg; average maximum pressure of 97.8 mm Hg was required for complete reduction. Average fluoroscopy time required for intussusception reduction was 94.8 seconds; an average of 41.8 seconds was required to exclude intussusception. Intussusception was diagnosed in 75 patients, and reduction was accomplished in 65 (87%). Of 100 consecutive patients that underwent hydrostatic reduction of intussusception at the authors' institution, reduction was successful in 55. Compared with hydrostatic enema, air enema involves shorter fluoroscopy time and lower radiation dose to the patient. Air enema is safe and effective for diagnosis and treatment of intussusception in infants and children and has replaced hydrostatic enema for such procedures at the authors' institution.

Enema↗