(P-26) Radiologic Techniques Used to Diagnose Cancer: An Educational Model for General Practit ioners Victoria E. Major, BS University o f Arkansas for Medical Sciences, Little Rock, AR, Teresita L. Angtuaco, MD, Mari lyn Fulper-Smith, Thomas R. Gest, PhD, Dashilee H. Berry, M D

A computer teaching module was developed as an independent learning tool for pr imary care physicians and medical students. The two main purposes o f this module are (1) to demonstrate the utility of various radiological procedures in the diagnosis o f cancer and (2) to review the physical principles involved in producing an image. The program is divided into six sections: introduction, plain f i lm ra- diography, CT, MRI, nuclear medicine, and ultrasound. Within each section, the following topics are covered: radiation exposure, invasiveness, indications for use, description of the procedure, ad- vantages, and disadvantages. Additionally, an option is provided within each section to allow the viewer a more in-depth discussion of the mechanics and physics involved in obtaining the image. The module was created utilizing Authorware and Photoshop computer software. The presentation includes images created us ing computer graphic and animation as well as scanned images f rom radiological teaching material. The module takes approximately 40 minutes to complete and the viewer, through interaction with the program, can tailor the entire learning experience. It is hoped the viewing physi- cian will have a better understanding o f how each radiological tech- nique can best be utilized in the diagnosis o f disease.

(P-27) The Effect of Breath-Holding in BOLD Signal Saussan Madi, MS Thomas Jefferson University Hospital, Philadel- phia, PA, Jonathan Nissanov, Phi), S imon Vinitski, PhD, A d a m E. Flanders, M D

Purpose : Study effect of apnea on the global B OL D signal of the brain and its interaction with f inger tapping signal.

Methods : GRE-EPI single shot images were obtained on 1.5T Si- gna scanner. Imaging parameters were TE/TR/Flip = 20 msec/2000 msec/90. Slice thickness 6 ram, F OV was 24 cm, and matr ix size 128 × 128. Image processing was performed us ing "Medx" release 3.0 functional MRI package. Subjects were imaged cont inuously as they breathed normally, inspired deeply and then held their breath for 45 sec. This was followed by 15 sec breathing, 15 sec breathing and fingertapping, 15 sec breathing, 15 sec of holding breath, 15 sec of holding breath and tapping, then finally 15 sec o f holding breath.

R e s , l t s : An initial signal decrement in the gray matter reaching a m a x i m u m of 0.5 -+ 0.71% approximately 10-15 sec after com- mencemen t o f apena. This is fol lowed by a gradual recovery. No in- teraction between holding breath and finger tapping was detected.

Conc lu s ion : The decreas ing arterial oxygen leads to increased venous d e o x y h e m o g l o b i n concentra t ion and to s ignal decrement . This is counterac ted by increased blood flow in response to the increased pCO2. The f inger tapping signal dur ing breath hold ing is independen t of breath holding.

(P-28) Esophageal Carcinoma: Current Staging and Imaging Jeffrey T. Hu, M D Wake Forest University School o f Medicine, Winston-Salem, NC, David J. Ott, MD, Nell T. Wolfman, M D

Purpose : Squamous cell carc inoma (SCC) is the mos t c o m m o n esophageal mal ignancy, and early detection and staging impacts on treatment and prognosis . A mult imodali ty approach to diagnosis, staging, and treatment is used currently. The objective of this pre- sentation is to review current staging and imaging of SCC.

Ma te r i a l s a n d M e t h o d s : Staging of SCC involves the use of the T N M sys tem which emphas izes depth o f wall invasion by the m a -

l ignancy and status of regional lymph nodes. Imaging modalities used to evaluate SCC include the bar ium esophagram, CT, and en- doscopic ul trasound (EUS). The staging sys tems and imaging tech- niques for evaluating SCC are reviewed and illustrated.

Resu l t s : The ba r ium esophagram is used for detect ion o f SCC of the esophagus , a l though size o f the tumor m a y predict an early vs. advanced mal ignancy . CT and EUS impact on s taging o f SCC and m a y de termine preoperat ive t rea tments but have shown a wide range o f reported accuracies in s taging SCC. EUS m a y de termine T1/T2 vs. T3 /T4 lesions wh ich cannot be as- sessed by CT, but CT better evaluates more advanced SCC.

C o n c l u s i o n : This scientific exhibit will preeent current staging and imaging o f esophageal SCC. Staging systems, multiple imaging modalities, and comparat ive efficacies of these modalit ies are dis- cussed and illustrated.

(P-29) Role of Functional MR Diffusion-weighted Image Sequence in Stroke Vikram S. Dogra , M D Erie County Medical Center, Buffalo, NY, Nitin P. Shirodkar, MD, Ange lo M. DelBalso, MD, DDS

Funct ional magne t i c resonance (MR) dif fus ion weighted images can d iagnose ear ly cerebral infarct ions wi thin hours o f its onset , as opposed to compu ted tomography , which fails to detect 60% of cases wi thin 24 hrs. The purpose o f this exhibi t is to empha- size the increas ing role o f funct ional M R diffus ion weighted im- ages, in d iagnos ing early cerebral infarct ions and different iat ing t hem f rom t ransient i schemic attacks (TIAs), enabl ing the insti- tut ion o f early thrombolys is . 30% of cl inically d iagnosed cases of s t roke are secondary to TIAs. A posi t ive resul t in di f fus ion- we igh ted images excludes the possibi l i ty o f TIA, m in imiz in g unnecessa ry thrombolyt ic therapy. The no rma l cerebral ana tomy and acute cerebral infarctions seen with functional M R diffusion weigh ted imag ing technique, inc luding var ious parameters aiad its bas ic phys ics , are depicted and discussed.

(P-30) Bilateral Biliary Drainage: Variations on a Theme Julia Gates, M D Beth Israel Deaconess Medical Center, Boston, MA George G. Hartnell , M D

Purpose : Bilateral biliary disease, whether benign or malignant, can be difficult to drain completely by endoscopic or percutaneous approaches. Mos t patients are treated by c o m m o n duct stenting or, for more proximal obstruction, are stented or drained unilaterally, sacrificing one hepatic lobe. Bilateral internal drainage us ing metal stents up to or including the c o m m o n duct might overcome these difficulties. This will illustrate stent combinat ions and spatial rela- t ionships used to provide bilateral biliary drainage. Stent configu- rations required to achieve bilateral internal drainage are related to etiology, complications and outcome. This includes a true "Y" stent configuration created by forming a hole in the side of one Wallstent, pass ing another Wallstent into the lumen and then fash- ioning another hole in the wall of the second Wallstent. Experience o f bilateral biliary drainage f rom 25 patients will be presented, in- chiding data on complications and need to reintervene. Bilateral biliary drainage, mos t easily accomplished us ing side-by-side me- tallic stents, can be achieved by percutaneous construction of Y- shaped stent pathways, allows effective bilateral biliary drainage, and avoids loss of liver t issue by leaving one lobe undrained.

(P-31) Improving the Quality of Diagnostic Ateriography in High-Risk Patients with Severe Peripheral Vascular Disease George G. Hartnell , M D Beth Israel Deacon. ess Medical Center, Boston, MA, Julia Gates, MD, Jona than Underhi l l , BS, C a m e r o n Akbari , M D

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