Choroid plexus changes after temporal lobectomy.

BACKGROUND AND PURPOSE: Postoperative contrast-enhanced MR imaging of the brain is routinely used when evaluating for residual or recurrent brain tumor. It is imperative to be aware of morphologic changes and imaging features that typically occur in response to surgical manipulation at the postoperative site to avoid misinterpretation of imaging findings. Our purpose was to determine normal postoperative changes and alterations in the choroid plexus among patients who had undergone temporal lobectomy in order to distinguish this appearance from pathologic changes that may be seen in the presence of infection or recurrent tumors. METHODS: We reviewed 159 MR scans from 95 patients with hippocampal sclerosis or gliosis who underwent temporal lobectomy for treatment of intractable epilepsy. Choroid plexus location and size were assessed on contrast-enhanced T1-weighted images. RESULTS: After temporal lobectomy, the choroid plexus enlarged and sagged into the resection site. Increase in the size of the choroid plexus occurred in 58% of cases overall. The degree of enhancement also increased after surgery, sometimes resulting in a nodular pattern of enhancement. The changes were most marked during the 1st week after temporal lobectomy, and showed an enlarged, markedly enhancing choroid plexus on 86% of the scans. CONCLUSION: Postoperative changes of the choroid plexus after temporal lobectomy include sagging into the resection site, an increased size, and an increased degree of enhancement. Normal postoperative morphologic characteristics may mimic neoplastic enhancement pattern. Familiarity with this appearance is important to avoid a pitfall in diagnosis of recurrent postoperative temporal lobe neoplasms.

Unusual presentations of sellar arachnoid cyst.

This report describes two unusual cases of parasellar arachnoid cyst with different neuro-ophthalmologic manifestations and clinical courses: a 33-year-old woman with parasellar arachnoid cyst, manifested by incongruous homonymous hemianopia, and a 64-year-old man with a presumed parasellar arachnoid cyst and bitemporal hemianopia that subsequently decompressed spontaneously. Parasellar arachnoid cyst is uncommon, and the clinical course has been incompletely described in the literature. Optimal treatment of patients with these cysts necessitates better understanding of their signs, symptoms, and clinical course.

Postoperative changes in the brain: MR imaging findings in patients without neoplasms.

PURPOSE: To determine the time course of postoperative changes in the brain by using magnetic resonance (MR) imaging. MATERIALS AND METHODS: Contrast material-enhanced MR images (32 preoperative, 161 postoperative) in 95 patients who underwent temporal lobectomy for treatment of nonneoplastic epilepsy were evaluated for enhancement pattern at the surgical margin and for the presence of dural enhancement, fluid, and air. Images were obtained 9 hours to 5.6 years after surgery. RESULTS: Surgical margin contrast enhancement was present and increased from 20 hours to 29 days after surgery. The predominant early (days 0-5) pattern was thin linear enhancement (16 of 18 [89%] images). The later (days 6-29) pattern was thick linear or nodular (tumorlike appearance) (11 of 18 [61%] images). Surgical margin enhancement was absent after day 30, although few data were collected 1-5 months after surgery. Dural enhancement was seen on 96 of 97 (99%) postoperative MR images. Extraaxial fluid was seen on all 46 images obtained during the first 30 days and was absent by day 51. Intracranial air was present on 31 of 35 (89%) images obtained during the first 4 days but was absent after day 5. CONCLUSION: Knowledge of the evolution of contrast enhancement patterns on postoperative MR images of the brain can help in differentiating benign from neoplastic changes.

MRI of giant cell tumor of the tendon sheath in the cervical spine.

The authors present a case of giant cell tumor of the tendon sheath (GCTTS) in the cervical spine, not previously described in the radiologic literature. Diagnostic imaging includes plain film radiographs, bone scintigraphy, CT, and MRI. Only one case of tenosynovial giant cell tumor of the cervical spine has been reported. The radiological features of this tumor are described along with a brief review of GCTTS.

Spinal imaging.

The application of magnetic resonance imaging has changed the evaluation of most disorders of the spinal axis. Contrast agents improve lesion conspicuousness and new sequences decrease both imaging time and artifacts. Myelography, computed tomography, and angiography continue to have well-defined, albeit limited, roles in spinal imaging.

Right atrial myxoma. A cause of septic pulmonary emboli in an adolescent female.

An adolescent girl presented with fever, headache, and mental status changes. Blood cultures 12 hours after admission were positive for Staphylococcus aureus. The initial evaluation did not reveal a source of the patient's sepsis. Forty-eight hours after admission a cardiac ejection click was detected. The chest radiograph showed ill-defined opacities compatible with pulmonary emboli in the right lung and a calcific density in the region of the right atrium. Echocardiogram confirmed the presence of a right atrial mass, which at surgery and upon histologic examination was a myxoma. Atrial myxomas are rare tumors in adolescents but should be considered in the differential diagnosis of suspected septic pulmonary emboli.

MR imaging of postpartum cortical blindness.

Cortical blindness is an unusual feature of the toxemia of pregnancy syndrome. We present the CT and magnetic resonance (MR) findings in two women who developed postpartum blindness as a manifestation of this condition. Though both CT and MR display reversible edematous changes in the occipital lobes, follow-up MR documents areas of hemorrhagic and nonhemorrhagic infarction where the corresponding CT images are normal.

The sensitivity of plain films for detecting perforation in children with appendicitis.

The plain films of 37 patients under age 18 with surgically and pathologically proven non perforated (16/37) and ruptured (21/37) appendicitis were reviewed in order to determine the ability of the plain film to specify perforation. Perforation was suggested when one or more of the following six findings were clearly defined: 1. Acute small bowel obstruction. 2. Extraluminal gas. 3. Mass in the right lower quadrant. 4. Colon cut-off sign at the hepatic flexure. 5. Fecalith. 6. Obliteration of the pelvic fat planes. This approach resulted in a sensitivity of 80% and a specificity of 94%, with the only false positive for perforation occurring in a patient with a fecalith. In five patients, extraluminal gas produced a triangular accumulation in the right flank which could be distinguished from intraluminal bowel gas on the supine or prone film.

Segmental intestinal muscular thinning: a possible cause of intestinal obstruction in the newborn.

Intestinal obstruction proximal to a transition zone without an interposed physical barrier usually indicates Hirschsprung disease. The authors report one case of focal small bowel muscular thinning just distal to a transition zone that produced clinical and radiographic findings that simulated long-segment Hirschsprung disease in a 2-day-old infant.

A new approach to the problem of retinal neovascularization.

Tumor cells introduced into the rabbit vitreous produced a form of retinal neovascularization, but only when the tumor cells were in direct contact with the vascularized retina. This contrasted with the production of neovascularization at a distance of several millimeters in other angiogenesis models. An extract of adult rabbit vitreous was found to inhibit the growth of limbal neovascularization induced by tumors implanted in the rabbit corneal stroma. The experimental model of retrolental fibroplasia provides a bioassay to investigate further the apparent inhibitory substances in the vitreous.