Papillary thyroid carcinoma is a common thyroid malignancy that generally has a good prognosis. However, this type of cancer may give rise to distant metastasis and may behave more aggressively in older patients. Here we report clinical, radiological, and pathological findings of a patient with papillary thyroid carcinoma who had a solitary cerebellar metastasis. The patient was known to have metastatic thyroid cancer to the lungs, but this had been stable and the cerebellar metastasis presented an unanticipated significant problem. The rapid detection of cerebellar metastatic disease is critical because neurosurgical removal of the solitary lesion should be considered as the treatment of choice. This case also serves to remind us of the importance of considering possible metastatic brain lesions and their acute life-threatening complications in contrast to the relatively prolonged course associated with metastases of thyroid carcinoma to other organs.

The eye movements are controlled by the cranial nerves 3, 4, and 6 working in close cooperation under the supervision of the voluntary cortex. Clinically, the most common presentation of abnormal ocular motor motion is double vision. A thorough clinical examination can usually separate a local orbital cause which can produce a restriction of the muscles moving the eye from a neurogenic cause due to an abnormality of one of the three nerves or their association pathways. Recent articles in the scientific literature have described major advances in our understanding of the anatomy and vascular relationships of the three ocular motor nerves (cranial nerves 3, 4, and 6) and of the diagnosis and treatment of a variety of pathological processes that damage these nerves, including ischemia, inflammation, and compression.

Sarcoidosis is a common multisystem disorder characterized by noncaseating epithelial granulomata, with osseous involvement typically seen in 5% of patients. While the lace-like or cystic pattern frequently seen in radiographs of the phalanges is well appreciated, sclerotic lesions of the spine are uncommon. We review a case of sarcoidosis of the cervical spine with sclerotic changes that mimicked blastic metastatic disease.

Chronic inflammatory demyelinating polyneuropathy (CIDP) has occasionally been associated with clinical or laboratory evidence (magnetic resonance imaging, [MRI], visual evoked response, and brainstem auditory evoked response [BAER]) of cranial neuropathy. In most cases, the relationship of cranial nerve involvement to CIDP remains unclear. A 45-year-old woman noted foot numbness, limb weakness, gait and postural instability, and oscillopsia. An IgG kappa monoclonal gammopathy of undetermined significance was found. Bilateral vestibulopathy was documented by clinical examination, bithermal calorics, rotary chair testing, BAERs, and dynamic posturography. MRI with gadolinium demonstrated enhancement of cranial nerve VIII bilaterally. Over the next 6 years, the patient's relapsing and remitting course of CIDP and vestibulopathy was assessed by quantitative muscle and vestibular function testing (clinically and neurophysiologically), and dynamic visual acuity. There was a striking synchronization between her CIDP and vestibulopathy with respect to clinical course including relapses and responses to immune therapy. The response to therapy, and evidence derived from clinical and laboratory investigations, suggest that the vestibular dysfunction was immune mediated.

OBJECTIVE:To assess the value of a hyperdense focus seen on CT scans of endometrial cysts in the differential diagnosis of a lesion.MATERIALS AND METHODS:The preoperative CT scans of 328 patients with 410 ovarian masses (54 patients with 62 pathologically proved endometriomas and 274 patients with 348 pathologically proved other ovarian masses) were retrospectively reviewed in a random fashion without knowledge of the pathologic findings to determine whether a hyperdense focus was visible inside a cyst.RESULTS:In nine of 62 endometrial cysts (sensitivity, 15%), CT scans showed a hyperdense round or crescent-shaped focus, measuring 2 to 15 mm. This focus was located close to the inner border of the cyst in eight cases and in the central part of the cyst in one case. A hyperdense focus was not seen on CT scans of 348 other ovarian masses (specificity, 100%). An in vitro CT study of two specimens showed that this hyperdense area corresponded to a blood clot next to the inner wall of the cyst. This hyperdense area appeared as a nonspecific hyperechogenic focus on sonograms in five of nine cases and as a hypointense signal on T1- and/or T2-weighted MR images in four of five cases.CONCLUSION:The finding on CT scans of a hyperdense focus inside an ovarian cyst is suggestive of endometrioma and should help distinguish endometrioma from other pelvic masses.

Neurosyphilis, a sexually transmitted disease that can cause neurologic damage, has become increasingly prevalent in the AIDS era. HIV carriers can contract neurosyphilis without the presence of other concurrent opportunistic infections. Because MR findings of neurosyphilis are seldom reported, we retrospectively reviewed and evaluated contrast-enhanced MR images of six young (average age, 33 years) HIV-positive men with high serum and CSF VDRL titers indicative of neurosyphilis. All six patients tested negative for concurrent opportunistic infections. Five patients had acute or subacute strokelike symptoms involving the basal ganglia or middle cerebral arteries; one had a parietal convexity mass mimicking meningioma with headache and ataxia. Contrast-enhanced MR images showed patchy enhancement involving the basal ganglia and middle cerebral artery territories in the first five patients and the convexity mass in the sixth patient. On the basis of brain biopsy, a convexity mass was diagnosed in the patient with syphilitic gumma. The imaging findings of the remaining five patients represented ischemic infarct caused by meningovascular syphilis. After penicillin treatment, serum and CSF VDRL titers decreased, and neurologic signs and symptoms improved in all six patients. A follow-up MR study in the patient with the gumma showed that the lesion resolved almost completely. In young HIV patients with stroke symptoms or a convexity mass, neurosyphilis should be considered. Contrast-enhanced MR can reveal the extent of involvement by neurosyphilis and should be used to facilitate diagnosis and proper treatment.

Correlation of imaging and anatomic findings in seven men with abdominal aortic graft prostheses (four "end-to-end" anastomoses and three "end-to-side" anastomoses) was done to compare the value of different imaging modalities in detecting postoperative complications, especially aortic anastomotic pseudoaneurysms (AAPs). In all cases, angiographic and CT studies were carried out. In six patients ultrasound and MR examinations were also performed. Anatomic verification was obtained by surgery in six patients and autopsy in one case. Five patients had an AAP (four at surgery and one at autopsy), one had a true abdominal aortic aneurysm above the anastomosis, and one a nondetectable abnormality of the aortic suture line. Digital subtraction angiography diagnosed one of five AAPs, missed the true aneurysm in the sixth patient, and was normal in the patient without any aneurysm. Computed tomography correctly diagnosed the five AAPs and the true aneurysm and was normal in the last patient. Ultrasound correctly diagnosed the AAPs in three of four patients, incorrectly diagnosed an AAP in the patient who had the true aneurysm, and was normal in the patient without any aneurysm. Magnetic resonance diagnosed four of four AAPs and the true aneurysm and was normal in the last patient. Computed tomography seems to be the best imaging modality with which to diagnose and evaluate an aortic AAP in patients with aortoiliofemoral graft prosthesis.

From its very beginnings, magnetic resonance imaging (MRI) has been able to demonstrate cerebral blood vessels because of their unique physical characteristics. The vessels appear as areas of signal void, which are easily seen against the higher intensity of the brain parenchyma [1]. With further experience MRI was able to identify not only the normal large extracranial arteries, but also small intracranial arteries and veins. If certain pitfalls related to flow effects on MR images are recognized, a large spectrum of vascular anomalies can be confidently diagnosed. This article reviews some aspects of the normal cerebral vascular anatomy and discusses some vascular anomalies as they appear on MRI.

Gated and nongated magnetic resonance (MR) scans of the chest were compared in five normal volunteers and 20 patients with chest disease to determine possible advantages of gated MR for delineation of noncardiac mediastinal anatomy. In order to compare gated and nongated images of the chest using similar imaging parameters, five spin-echo sequences were obtained in each of five normal volunteers: TR: 1000 msec, TE: 30 msec; gated to every heart beat (TR approximately 1000 msec, TE: 30 msec); TR: 2000 msec, TE: 30 msec; gated to every other heart beat (TR approximately 2000 msec), TE: 30 msec; TR: 500 msec, TE: 30 msec. In the 20 patients, the gated images were gated to every heart beat and the nongated images were obtained using a TR of 2000 msec, both with a TE of 30 msec. The noise in the periphery and in the center of the gated and nongated images at the level of the carina was compared in the five normal volunteers, using the signal intensity of the posterior chest wall as a control. There was 92% +/- 44% greater noise in the central region and 63% +/- 60% greater noise in the peripheral region on the nongated studies (TR: 1000 msec), than on the studies gated to every heart beat. In three of the five volunteers, the measured noise was greater on the nongated long TR (2000 msec) images than on the images gated to every other heart beat. However, the mediastinal structures below the level of the aortic arch were much better defined on the gated images in all five subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

The ability to distinguish intrathoracic from intraabdominal fluid collections has important therapeutic implications. In the setting of peridiaphragmatic fluid collections CT accurately distinguishes between pleural and subphrenic fluid collections in most cases. Subpulmonic effusions represent a potential pitfall to CT diagnosis, however, because the atelectatic basilar lung segments appear on axial CT sections as a curvilinear band density that simulates the hemidiaphragm. Fluid found anterior to this "pseudodiaphragm" will erroneously be diagnosed as subphrenic unless the atelectatic lung is recognized as such. New CT observations are reported that allowed confident diagnosis in 18 consecutive cases of subpulmonic effusions. The atelectatic lung was distinguished from the diaphragm because the atelectatic band appeared thickened (17 of 18 cases), tapered laterally (14 of 18), was interrupted rather than continuous (17 of 18), and could be followed in contiguous cephalad sections into lung that was confidently recognized by the presence of gas bubbles or air bronchograms (12 of 18).

In 10 mongrel dogs, the sonographic features of the pelvocaliceal system and ureteral peristalsis during acute rejection were correlated with the electromyographic (EMG) findings and histologic appearance. There were significant alterations of the ureteral dynamics during rejection as demonstrated by changes in the pressure tracings, the progressive decrease of electrical activity of the ureteral muscle, and decreased peristalsis with pelvicaliectasis as demonstrated on real-time ultrasound. The sonographic changes of peripelvic and periureteral thickening corresponded to histologic changes of edema and inflammatory infiltrate with disruption of the muscular layer. In the presence of clinical and sonographic findings of kidney rejection, the demonstration of hydronephrosis and thickened pelvic wall should be considered as another measure of the rejection process.

Aortic graft infections are a rare but potentially lethal complication of aortic graft surgery. If the infection is limited to the groin, local therapy and preservation of the graft may be possible in some cases, whereas infections extending into the retroperitoneum require removal of the graft and revascularization of the lower limbs. The diagnosis and assessment of the extent of a graft infection is difficult on clinical grounds. A prospective study compared CT and indium-labeled white blood cell (In-WBC) scans in the diagnosis of aortic graft infection. Five patients with aortic graft infection and three patients without aortic graft infection were studied by both methods. CT correctly detected the retroperitoneal extension of the infection in three patients with groin infection; In-WBC scans diagnosed the extension only in one patient. Both CT and In-WBC were positive in two patients with aortic graft infection but no groin infection. Both studies were negative in the three patients without evidence of aortic graft infection. The study suggests that CT is more sensitive than In-WBC in evaluating the extent of aortic graft infection and should be the imaging method of choice.

Computed tomography scans of the larynx were obtained during quiet breathing and during phonation in 10 volunteers having no neck or larynx abnormalities. The subglottic and glottic laryngeal cavity and soft tissues showed symmetry from side to side. At the supraglottic level, the pliable aryepiglottic folds and pyriform sinuses appeared moderately asymmetric and variable during quiet breathing. Phonation made them more symmetric. Phonation also allowed accurate determination of vocal cord function. The laryngeal cartilages were symmetric in their degree of calcification and had clearly visible centers of dense calcification. Computed tomography is a highly precise method for demonstrating the structures of the larynx.