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Biomedical subjects

R P Tart

Publications and source records attributed to R P Tart.

At least 19 recordsLinked to original sources
PubMed2000

Postcricoid region and cervical esophagus: normal appearance at CT and MR imaging.

PURPOSE: To establish the normal variations of the postcricoid portion of the hypopharynx, esophageal verge, and cervical esophagus, as seen on computed tomographic (CT) and magnetic resonance (MR) images. MATERIALS AND METHODS: One hundred twenty-one CT and 92 MR images were reviewed. Diameter and wall thickness were measured at multiple levels. Depiction of the layers of the musculature and adjacent fat planes was evaluated. The frequency and size of the tracheoesophageal lymph nodes were noted. RESULTS: An esophageal anteroposterior diameter greater than 16 mm and lateral diameter greater than 24 mm were considered abnormal. The average wall thickness was 4.8 mm laterally and 3.8 mm posteriorly. Demonstration of the intramural fat planes of the postcricoid region decreased from the upper to the lower region of the cricoid cartilage. The ability to separate the esophageal wall from the trachea was highest at the esophageal verge and declined markedly more distally. The tracheo-esophageal groove nodes were seen more often on the right (mean size [+/- SD], 4.5 mm +/- 2.2). CONCLUSION: Knowledge of the normal appearance and variations of the post-cricoid region and cervical esophagus is essential in detecting abnormalities in these areas.

Adolescent↗
PubMed1998

Arytenoid cartilage sclerosis: normal variations and clinical significance.

PURPOSE: Our purpose was to determine the variation in location, distribution, and sex predilection of arytenoid cartilage sclerosis in a population of patients without laryngeal cancer as an aid to understanding the significance of this entity when seen in patients with laryngeal cancer. METHODS: One hundred CT examinations of patients of different ages and with no history of laryngeal cancer or radiation therapy were evaluated for the presence of arytenoid cartilage sclerosis. The arytenoid cartilage was subdivided into three regions: superior process, body, and vocal process. Each region was assessed on each side separately on bone window scans. RESULTS: Arytenoid cartilage sclerosis was seen in 16% (n = 16) of the patients. Sclerosis was most common in the body (n = 12) and least common in the true vocal process (n = 2); the left side was the preferred location for all three regions. In 50% of the patients, at least two regions were affected. Eighty-one percent of sclerotic arytenoid cartilage was seen in women. CONCLUSION: Knowledge of the frequency and distribution of arytenoid cartilage sclerosis as a normal variant can aid in determining the risk of arytenoid cartilage involvement in patients with laryngeal cancer.

Adolescent↗
PubMed1995

CT and MR imaging of the buccal space and buccal space masses.

The authors describe the normal variations in the buccal space and present the range of buccal space pathologic conditions seen on computed tomographic (CT) and magnetic resonance (MR) images. In a series of 50 patients studied with CT and 30 with MR imaging, the visualization and measurement of the normal facial expression and buccinator muscles, parotidomasseteric fascia, parotid duct, accessory parotid tissue, and facial neurovascular bundle were statistically equivalent. The size of the buccal fat pad was statistically the same from side to side within a given patient. Normal lymph nodes were rarely discernible from the facial neurovascular bundles. In a series of 26 patients with unsuspected buccal space masses, salivary gland tumors were the most common masses. Less frequently, benign lesions (eg, hemangioma and dilated parotid ducts) and soft-tissue malignancies (eg, sarcoma) manifested as buccal space masses. Occasionally, a cheek mass of uncertain cause proved to be lymphadenopathy; however, adenopathy is more commonly associated with clinically evident, deeply infiltrating facial neoplasms. Knowledge of the anatomic variations and expected abnormalities of the buccal space is useful for the radiologist interpreting facial CT or MR images.

Adult↗
PubMed1994

Value of laryngeal cartilage sclerosis as a predictor of outcome in patients with stage T3 glottic cancer treated with radiation therapy.

PURPOSE: To determine whether sclerosis of the laryngeal cartilages was a predictor of a poor outcome in patients with stage T3 glottic cancer treated with radiation therapy. MATERIALS AND METHODS: Thirty-three patients with stage T3 glottic cancer underwent computed tomography (CT) before radiation therapy. Twenty-two patients underwent posttreatment CT. The presence of cartilage sclerosis, cartilage erosion, marrow invasion, and cartilage necrosis was determined. RESULTS: Nineteen of the 33 patients had cartilage sclerosis at CT. Seventeen patients had sclerosis of a single laryngeal cartilage (14 arytenoid, two cricoid, and one thyroid), and two had sclerosis of adjacent laryngeal cartilages (arytenoid and cricoid in both cases). Of the 17 patients with isolated laryngeal cartilage sclerosis, disease was controlled with radiation therapy alone in 15 and with salvage laryngectomy in two. Both patients with cricoid and arytenoid sclerosis died of their original cancer despite undergoing early salvage laryngectomy. Of the 14 patients without sclerosis, eight had no evidence of disease, two died of their disease, and four died of intercurrent disease. CONCLUSION: T3 glottic cancer with isolated laryngeal cartilage sclerosis can be cured with radiation therapy.

Glottis↗
PubMed1994

Radiologic appearance of the irradiated larynx. Part I. Expected changes.

PURPOSE: To present the expected appearance of the irradiated larynx and neck as seen at computed tomography (CT). MATERIALS AND METHODS: Sixty-one patients with primary squamous cell carcinoma of the larynx or hypopharynx were treated with radiation therapy. All patients underwent CT before and after treatment. RESULTS: Expected changes include symmetric thickening of the epiglottis, aryepiglottic folds, and false cords and increased attenuation of the paralaryngeal fat. The posterior pharyngeal wall tends to thicken and its mucosa enhances; retropharyngeal space edema is common. Glottic changes include increased attenuation of the paraglottic fat planes and thickening of the anterior and posterior commissures. Subglottic changes include thickening of the mucosa and submucosa. Soft-tissue changes include skin and platysmal thickening, as well as reticulation and increased attenuation of the subcutaneous and deeper fat. CONCLUSION: Familiarization with expected radiologic changes is essential for interpretation of CT images of the irradiated larynx so that such changes are not mistaken for signs of persistent or recurrent tumor.

Carcinoma, Squamous Cell↗
PubMed1994

Radiologic appearance of the irradiated larynx. Part II. Primary site response.

PURPOSE: To evaluate the computed tomographic (CT) appearance of laryngeal tumors treated with radiation therapy and the ability of CT to depict persistent or residual tumor. MATERIALS AND METHODS: Sixty-one patients with primary squamous cell carcinoma of the larynx or hypopharynx were treated with definitive radiation therapy. CT was performed in all patients before and after treatment. RESULTS: In 32 of 41 patients with cancer controlled at the primary site, CT showed complete resolution of tumor, whereas in 10 of 14 patients in whom radiation therapy failed, there was minimal or no reduction in tumor. In a subpopulation of patients who underwent repeat imaging, 18 of 19 with tumor controlled at the primary site had complete resolution of tumor. Overall, in four of 13 patients with 50%-75% reduction in tumor size or persistent substantial asymmetry at CT, therapy eventually failed at the primary site. CONCLUSION: Lesions that are reduced by 50% or less at 4-month follow-up CT are highly suspicious for treatment failure. Repeat CT studies every 4 months is recommended in addition to careful clinical follow-up.

Carcinoma, Squamous Cell↗
PubMed1994

CT of the temporal bone: findings after mastoidectomy, ossicular reconstruction, and cochlear implantation.

Because of its superior visualization of bone detail, compared with that of MR imaging, CT commonly is used in patients who have had otomastoid or other forms of temporal bone surgery. The already complex anatomy of the temporal bone is distorted by the combination of surgical procedures and preexisting abnormalities, making proper identification of the postoperative imaging studies difficult. The purpose of this essay is to familiarize radiologists with the more common neurootologic surgical procedures and the expected postoperative findings in patients who have had this type of surgery. Special emphasis is placed on the indications for the procedure and the distinguishing features associated with each procedure.

Cochlear Implants↗
PubMed1994

Fat-suppressed MR of the orbit and cavernous sinus: comparison of fast spin-echo and conventional spin-echo.

PURPOSE: To compare T2-weighted fat-suppressed fast spin-echo imaging with fat-suppressed conventional spin-echo imaging in the detection of normal intraorbital and pericavernous anatomy and orbital disease, and to determine the efficacy of fat saturation with T2-weighted fast spin-echo imaging of the cavernous sinus. METHODS: Contrast-to-noise ratios of normal intraorbital anatomy were calculated and compared in 10 consecutive patients using fat-suppressed fast spin-echo and conventional spin-echo T2-weighted images. Contrast-to-noise ratios of common intraorbital lesions were calculated and compared using fat-suppressed fast spin-echo and fat-suppressed conventional spin-echo. Qualitative evaluation was performed and compared for normal intraorbital anatomy using both fat-suppressed fast spin-echo and fat-suppressed conventional spin-echo in 16 patients. Qualitative evaluation for the detection of normal anatomic structures of the pericavernous region was performed and compared using fast spin-echo with and without fat suppression and fat-suppressed conventional spin-echo T2-weighted images in 16 patients. Fat saturation was performed using standard commercially available chemical saturation technique. RESULTS: Reduced imaging time allowed more acquisitions for fat-suppressed fast spin-echo images, which significantly improved visibility of intraorbital and pericavernous anatomy over fat-suppressed conventional spin-echo. Anatomic visibility was also improved because of reduced motion, phase encoding, and susceptibility artifacts. There was no significant difference between contrast-to-noise ratios for fat-suppressed fast spin-echo and fat-suppressed conventional spin-echo imaging of the lateral and medial rectus muscles. Contrast-to-noise ratios of fat suppressed fast spin-echo of orbital disease was significantly greater than contrast-to-noise ratios of fat-suppressed conventional spin-echo. Detection of several normal anatomic structures of the pericavernous region was significantly improved with non-fat-suppressed fast spin-echo over fat-suppressed fast spin-echo because of significantly reduced magnetic susceptibility artifact. CONCLUSIONS: Fat-suppressed fast spin-echo is superior to fat-suppressed conventional spin-echo for T2-weighted orbital imaging. Non-fat-suppressed fast spin-echo is the preferred pulse sequence for T2-weighted imaging of the cavernous sinus because of the minimal susceptibility artifact.

Adipose Tissue↗
PubMed1994

Comparison of thallium-201 and F-18 FDG SPECT uptake in squamous cell carcinoma of the head and neck.

PURPOSE: To compare the uptake of 2-[F-18] fluoro-2-deoxy-D-glucose (fludeoxyglucose F-18; F-18 FDG) and thallous chloride Tl 201, using single-photon emission CT (SPECT), for the detection and location of squamous cell carcinoma of the head and neck. METHODS: Five patients with biopsy-proved squamous cell carcinoma of the upper aerodigestive tract underwent both F-18 FDG and thallium-201 SPECT on the same day. F-18 FDG SPECT was performed using a dual-head gamma camera equipped with commercially available, extremely high-energy collimators (full width half-maximal height, 17 mm for 511 keV photons). Tumor size was estimated at 1.0 to 5.0 cm3 in these cases. RESULTS: F-18 FDG SPECT showed five of five primary tumors. In two of the five cases, normal salivary gland activity severely limited thallium SPECT, and the tumors could not be definitively identified. Two of four lymph node groups that were positive for metastatic disease by CT criteria were shown by F-18 FDG SPECT. None were seen with thallium imaging. In one case, F-18 FDG SPECT was able to show a tumor that was not visible on CT. CONCLUSIONS: F-18 FDG has advantages over Tl-201 as a squamous cell carcinoma imaging agent (primarily because of its reduced salivary activity). F-18 FDG SPECT has potential as a viable, less expensive alternative to F-18 FDG positron emission tomography. The ultimate value of F-18 FDG SPECT imaging for detecting occult malignancy, monitoring therapeutic effectiveness, or evaluating tumor recurrence remains to be determined in patients with squamous cell carcinoma of the head and neck.

Biopsy↗
PubMed1994

Irradiated paragangliomas of the head and neck: CT and MR appearance.

PURPOSE: To present the spectrum of CT and MR findings of glomus tumors of the head and neck successfully treated with radiation therapy. METHODS: The patient charts and all CT and MR studies of 24 patients (25 tumors) who had been successfully treated with radiation therapy were retrospectively reviewed. Eighteen patients had pre- and posttreatment imaging studies. Tumor size, internal morphology, enhancement pattern, visualization of flow voids, and bone erosion were evaluated before and after radiation therapy. Statistical evaluation of the presence of flows voids and tumor size was performed using the Fischer Exact Test. RESULTS: All patients had residual tumor after radiation therapy. Sixty-one percent of tumors demonstrated a reduction in size. Only one tumor with pretreatment bone destruction demonstrated healing of the bone. MR findings after radiation therapy included variable alteration in T2 signal, decreased heterogeneous enhancement, and a reduction in flow voids. There was a significant difference in the presence of flow voids based on tumor size. CONCLUSIONS: Successfully irradiated paragangliomas demonstrate residual masses, the presence of which does not by itself indicate treatment failure. Stabilization or reduction in size, decreased enhancement, diminished flow voids, and reduced T2 signal after radiation therapy are a result of therapy and are indicative of local control. Persistent bone demineralization and erosion without progression is commonly seen in successfully controlled tumors. Paragangliomas are relatively homogeneous in internal morphology except for areas of flow void. Flow voids are not a reliable criterion for diagnosis in lesions less than 2.5 cm.

Adult↗
PubMed1994

A technique for core biopsies of head and neck masses.

A technique for performing core biopsies of indeterminate masses of the extracranial head and neck is described. Four patients with suspicious masses of the extracranial head and neck underwent coaxial core biopsies through an 18-gauge Hawkins-Akins blunt tip needle. Three of the four patients had diagnostically adequate samples. There were no neurologic or vascular complications.

Biopsy, Needle↗
PubMed1993

Facial lymph nodes: normal and abnormal CT appearance.

Facial lymph node involvement by neoplastic disease is an unusual occurrence. The purpose of this study was to determine the normal and abnormal radiologic appearance of the facial nodes. Two hundred enhanced computed tomographic (CT) studies of patients not at risk for facial node metastasis were studied prospectively to establish a normal control group. One hundred consecutive patients with extensive recurrent or primary cancer of the epidermal structures of the face, the sinonasal region or deep face, or the mucosal surface of the oral cavity were examined prospectively to establish a prevalence for metastatic facial adenopathy. In addition, all cases of facial node metastases seen on imaging studies over an 11-year period (n = 21) were examined retrospectively to establish the spectrum of facial lymphadenopathy. Normal nodes could not be confidently identified on CT studies. When nodal metastasis occurred, it was often in the setting of recurrent disease. The infraorbital nodes tended to be the site of origin for lymphomas isolated to the canine fossa.

Face↗
PubMed1991

Barium sulfate suspension as a negative oral MRI contrast agent: in vitro and human optimization studies.

In vitro proton spectroscopy with line-width measurements and MR imaging were performed on various concentrations of commercially available single contrast (SC), double contrast, oral and rectal barium sulfate suspensions, as well as potassium sulfate, barium chloride, barium hydroxide, and 97% pure barium sulfate suspensions. Approximately 500 ml of 20%, 40%, 60%, and 70% w/w suspensions of SC oral barium sulfate suspensions were administered to four normal volunteers, respectively, and MR images were obtained at both 1.5 T and 0.15 T. Subsequently, 500 ml of 60% w/w suspensions of SC oral barium sulfate suspensions were administered to five normal volunteers and imaged at 1.5 T. All of the inert suspensions produced line-width broadening but the SC oral barium sulfate suspension at 50% and 70% stayed in suspension even after hours of standing undisturbed. As much as 80% of the small bowel and the entire colon were well visualized using the combination of 60% or 70% w/w SC barium sulfate suspensions with SE 550/22 and FISP pulse sequences. The effect was less at 0.15 T and also with the SE 2000/45/90 pulse sequences. We conclude that barium sulfate suspensions are useful as oral MRI contrast agents.

Administration, Oral↗
PubMed1991

Enteric MRI contrast agents: comparative study of five potential agents in humans.

We compared the effectiveness of 1 mM Geritol, 12% corn oil emulsion, Kaolin-pectin, single contrast oral barium sulfate, and effervescent granules as enteric magnetic resonance imaging (MRI) contrast agents. Five volunteers were recruited. Each volunteer ingested for examinations, separated by at least one week, either 500 ml of each of the liquid preparations or two packets of the CO2 granules (producing 400 ml of CO2 per packet). Abdominal MR images were then obtained using a 1.5 T Magnetom imager and SE 550/22, SE 2000/45/90 and FISP 40/18/40 degrees pulse sequences. The oil emulsions were best tolerated. Barium sulfate caused the greatest amount of nausea, followed by Geritol and Kaolin-pectin. With FISP 40/18/40 degrees, 60%-80% of the small bowel was well delineated using oil emulsion, Kaolin-pectin, or barium sulfate. We conclude that oil emulsion was by far the best enteric MR contrast agent in our study. Good delineation of the small bowel and pancreas can be achieved using oil emulsion and gradient echo pulse sequences. The lack of side-effects and the excellent taste make it highly acceptable to human subjects.

Abdominal Pain↗
PubMed1991

Persistent nidus blood flow in cerebral arteriovenous malformation after stereotactic radiosurgery: MR imaging assessment.

Stereotactic radiosurgery has become a major force in the treatment of arteriovenous malformations (AVMs) of the brain. After treatment, obliteration of flow through the malformation occurs in 75%-85% of cases within 2 years, assuming the entire AVM nidus can be encompassed by the radiation field. Because the follow-up period is relatively long, a noninvasive means to assess residual transnidus blood flow is desirable. The authors report favorable findings after a comparative analysis of 85 posttreatment magnetic resonance images and 27 follow-up cerebral arteriograms in 34 patients treated with stereotactic radiosurgery. The authors found that transnidus flow can be determined from apparent signal intensity differences between tandem two-dimensional gradient-recalled echo images obtained first without and then with gradient moment nulling (flow compensation), with empirically derived pulse parameters. This method provides a means to monitor the reduction in AVM matrix size and to assess the extent of persistent arteriovenous shunting (ie, blood flow) across the nidus.

Brain↗