Biomedical subjects
Publications and source records attributed to D P Mayer.
The giant cholesterol cyst is a clinical entity distinct from cholesterol granulomas and other destructive lesions of the petrous bone. Preoperative assessment by computed tomographic scan and magnetic resonance imaging is extremely helpful. Attempts at total resection of the lesion are not necessary. Adequate surgical drainage may be established through the mastoid or middle fossa.
Intraoperative pancreatic ultrasound can be useful to identify small masses or cysts that are not readily palpable at surgery. In our case, a small (2.0 cm diameter) pseudocyst was demonstrated preoperatively by ultrasound and computed tomography, but could not be palpated at surgery. Intraoperative ultrasound located and helped to guide needle aspiration of the pancreatic pseudocyst. Other indications for intraoperative pancreatic ultrasound are reviewed.
Abdominal computed tomography (CT) scans of 55 patients who had ingested Gastrografin (meglumine diatrizoate and diatrizoate sodium) diluted to 2% with tap water and flavored with a commercial fruit juice base were reviewed. Twenty patients (36%) demonstrated intraluminal precipitation of Gastrografin shown by focal areas of markedly increased attenuation within the gastric lumen or trapped within gastric folds. Beam-hardening artifact produced by precipitation was observed, which limited the diagnostic value of some examinations. In vitro CT scans of the same Gastrografin solution titrated with hydrochloric acid or sodium hydroxide showed that by raising the pH of the solution, precipitation was virtually eliminated. Fifty-one CT scans of the abdomen using a buffered Gastrografin solution demonstrated precipitation in only five patients. Properly buffered dilute oral Gastrografin solutions should significantly decrease the prevalence of precipitation during abdominal CT examinations.
An analysis of the sonograms of 60 patients with a surgically confirmed diagnosis of ectopic pregnancy was performed. In 36 examinations, both real-time and static images were compared, and real-time was judged superior in 22 based on a correlation between the original report and surgical pathology. The appearance of the endometrial canal and the adnexa was characterized in a total of 65 scans. The endometrial canal appearance was variable, with the most common finding being a linear echo (39%). The adnexal changes were less diverse, with an adnexal ring suggestive of an extrauterine gestational sac identified in 60%. In 10 cases, the adnexal ring contained a distinct fetus with a measurable crown-rump length, and cardiac activity was evident in six. Our results indicate that real-time ultrasound coupled with serum beta-hCG RIA should be the procedure of choice when ectopic pregnancy is suspected.
Lipomas are very common benign soft tissue neoplasms arising from fatty tissue and may occur anywhere in the body. They are usually slow growing, painless masses often noted in the extremities of adult women. Occurrence in the hands and feet is unusual and those found in the digits are extremely rare. We describe a case of a lipoma presenting as a soft tissue mass of the index finger and show how computed tomography was extremely helpful in preoperative assessment by accurately defining the size of the lesion, the degree of bone involvement, and even giving indication of its underlying pathology.
Epithelium-lined cysts of the jaw can be either odontogenic or non-odontogenic. Cysts that exhibit keratinization of their epithelial lining are called odontogenic keratocysts. They compose approximately 8% of all odontogenic cysts. There is a frequent association with unerrupted teeth, and a high incidence of occurrence of keratocysts in the multiple basal cell nevus syndrome. The significance of odontogenic keratocysts is their high potential for recurrence after their removal. There is no specific radiographic feature, however, that distinguishes them from non-keratinized odontogenic cysts. High resolution computed tomography (CT) studies can exquisitely determine the extent of these lesions and pinpoint areas of cortical breakthrough as well as involvement of the teeth. This information is invaluable in surgical planning for excision of these lesions.
A patient with a surgically proven intracanalicular arachnoid cyst was studied using computed tomography, magnetic resonance imaging, and air CT cisternography. The lesion had a similar radiographic appearance to acoustic neuroma and therefore, although rare, must be considered in the differential diagnosis of intracanalicular mass lesions. We report a case in which examination was performed, in evaluating the lesion, utilizing high-resolution air CT cisternography and magnetic resonance imaging (MRI).
Distal biceps tendon rupture is a rare injury. While plain radiographs are usually not helpful in visualizing the defect, evaluation of the tendon with MRI has proven to be useful as it depicts complete anatomic detail of the tendon and associated structures. Its multiplanar imaging capability and superior soft tissue contrast resolution makes MRI a prime diagnostic tool in the diagnosis of tendon disorders. We report a case of complete rupture of the biceps tendon diagnosed by MRI.
Preoperative evaluation of patients with medically refractory complex partial seizures requires intensive EEG monitoring. Part of this process may include insertion of depth electrodes into temporal lobe structures. Although many imaging methods have been used for stereotactic placement of the electrodes, only computed tomography (CT) has been used to verify position after implantation. We studied 30 patients in whom magnetic resonance imaging (MRI) was used to visualize the position of stainless-steel electrodes stereotactically implanted in the temporal lobes. The procedure is noninvasive, does not utilize radiation, and has the additional advantages of multiplanar capability, increased soft tissue contrast, and lack of bony artifacts commonly associated with CT.
Magnetic resonance (MR) arthrography is a useful technique in evaluating the articular structures of the ankle. With intra-articular administration of gadolinium-DTPA (Gd-DTPA), visualization and delineation of anatomic structures, that would not be depicted by other traditional imaging techniques, are achieved. It is a technique that proves to be advantageous as it does not require the use of ionizing radiation, nor iodinated contrast material as other conventional diagnostic modalities. MR arthrography also allows multiplanar imaging and provides excellent resolution.
A 7-year-old black male presented with a lytic, expansile lesion of the calcaneus. This lesion was studied with conventional x-rays as well as MRI. The MR examination demonstrated a multiloculated lesion with material of a high- and low-signal intensity appreciated within each loculation. Pathologic review of the lesion demonstrated an aneurysmal bone cyst.