Search PubMed⌕ Search

Biomedical subjects

S F Quinn

Publications and source records attributed to S F Quinn.

At least 19 recordsLinked to original sources
PubMed2001

"Accordion" deformity of a tortuous external iliac artery after stent-graft placement.

PURPOSE: To identify a complication of endograft deployment in aneurysmal iliac arteries. CASE REPORT: A 71-year-old man was referred for endovascular treatment of a 60-mm-diameter right common iliac artery aneurysm; however, deployment of a homemade covered stent (Palmaz-Schatz and polytetrafluoroethylene) induced shortening of the tortuous external iliac artery, causing an "accordion" deformity. The anomaly proved difficult to treat with serial Wallstent deployment, because the convolution tightened and migrated caudally with each stent deployed, threatening outflow. Finally, after 3 Wallstents were implanted, the contour of the external iliac artery was straight, and flow was unimpeded. However, 3 weeks later, the external iliac artery had recoiled to its original redundant appearance, but flow remained satisfactory. The aneurysm remains excluded, with satisfactory distal flow after 24 months. CONCLUSIONS: Implanting endografts in redundant, tortuous arterial segments may prove problematic, since induced straightening by the device precipitates kinking in the redundant system. Although treatment may be required in some situations, the vessels may return to a noncompressed state by removing the delivery system and guidewire.

Aged↗
PubMed2000

Transluminally placed endovascular grafts to exclude undesirable intracardiac vascular communications.

PURPOSE: In this report, we summarize our early experience using transluminally placed endovascular grafts (TPEG) to close intracardiac communications within surgically created conduits. MATERIALS AND METHODS: Three patients with surgically corrected congenital heart disease were treated in this study. All three patients had intracardiac conduits [Modified Fontan (n = 2) or Mustard procedure (n = 1)]. All three patients had intracardiac shunts causing hypoxemia. The shunts were caused by a surgically created fenestration (n =1), a leak at a surgical anastomosis (n = 1) and perforations of a pericardial baffle (n = 1). All three patients were treated percutaneously from venous side approaches. The TPEG devices were constructed of pre-expanded polytetrafluoroethylene (PTFE) sutured to a Palmaz stent. RESULTS: In the two patients with the modified Fontan procedures, the leaks were completely excluded; in the patient with the Mustard procedure, the perforations in the baffle were not completely excluded. All patients experienced immediate improvements in oxygen saturation ranging from 17Eth 26% (mean, 20.3%). The improvements in oxygen saturation were sustained with values ranging from 12Eth 22% (mean, 17.3%) at the time of clinical follow-up. Clinical follow-up has ranged from 13Eth 19 months (mean, 15 months) and has demonstrated improved exercise tolerance and weight gain. Echocardiographic follow-up has shown no complications of TPEG stenoses, occlusions or migrations. There were no immediate or delayed complications associated with the TPEG devices. CONCLUSION: We report our experience using TPEG devices to exclude intracardiac communications in 3 patients with surgically corrected congenital heart disease. The preliminary results are encouraging and suggest that further investigation in this area should be done.

Adolescent↗
PubMed1999

Helical CT in the evaluation of renal colic.

This study assessed the clinical effectiveness of unenhanced helical (spiral) computed tomography (CT) for evaluation of patients presenting with symptoms of renal colic. Two hundred patients with symptoms and signs of renal colic (flank or groin pain, hematuria) were imaged. Unenhanced CT was performed using 5-mm collimation with a pitch of 1.5 to 1.8. Image reconstruction was performed at 3-mm intervals. Exam time was approximately 5 minutes. The financial charge at the study institution was the same as for an intravenous urogram. Clinical follow-up was performed by review of available medical records and patient interviews. The sensitivity for detecting clinically relevant ureteral and bladder calculi was 0.862 (0.95 confidence interval [CI] 0.771 to 0.927), the specificity was 0.914 (0.95 CI 0.837 to 0.962), and the accuracy was 0.89 (0.95 CI 0.833 to 0.931). Helical CT is an effective technique in the evaluation of suspected acute urinary tract obstruction.

Adolescent↗
PubMed1998

Single limb patency of polytetrafluoroethylene dialysis loop grafts maintained by traumatic fistulization.

The purpose of this report is to describe an unusual presentation of obstructive neointimal hyperplastic lesions in loop prosthetic dialysis grafts. The case histories and imaging studies of two patients with partial graft thrombosis are presented. The literature of unexpected fistulae from prosthetic dialysis grafts to adjacent veins is reviewed. Signs and symptoms that would lead a clinician to suspect the diagnosis are emphasized. There were two dialysis grafts with partial thrombosis and arterial limb patency maintained by iatrogenic fistula. These fistulae occurred from the erosion of pseudoaneurysms in one case and an apparent needle stick without pseudoaneurysm in the other. Both grafts had high-grade stenotic lesions affecting the venous outflow. In the first case this was not recognized until the graft reclotted 2 days after thrombectomy. In the most extreme cases of graft/vein fistulae, i.e., partial graft thrombosis with arterial limb patency maintained by the fistula there is always associated venous anastomotic or outflow stenoses which must be addressed.

Adult↗
PubMed1998

The answer is blowing in the wind: a pedunculated tumour with saw tooth flow-volume loop.

Obstructing tumours of the upper airways have been demonstrated to alter the flow volume loop of pulmonary function testing. These alterations could be clues to the nature and location of the obstruction. This report describes a case of a pedunculated squamous cell carcinoma arising in the pharynx whose flow volume loop showed a saw tooth pattern which reflected the location and structure of the tumour.

Airway Obstruction↗
PubMed1998

Aortic and lower-extremity arterial disease: evaluation with MR angiography versus conventional angiography.

PURPOSE: To compare magnetic resonance (MR) angiography with conventional angiography in evaluation of the aorta and lower-extremity arterial system. MATERIALS AND METHODS: Fifty-seven patients were evaluated with femoral conventional and MR angiography. Iliac artery segments were evaluated with two-dimensional and contrast material-enhanced three-dimensional time-of-flight MR angiography. Infrainguinal regions were evaluated with two-dimensional time-of-flight MR angiography with a dedicated lower-extremity coil. Arteries depicted on femoral images were separately interpreted as 20 anatomic segments. Disease classification included normal to moderate disease (0%-50% stenosis), severe stenosis (> 50% stenosis), diffuse disease (more than one severe stenosis), and occlusion. Four readers interpreted the images and rendered treatment recommendations. RESULTS: Substantial to almost perfect interobserver agreement (kappa, 0.66-1.00) was achieved in most cases for MR angiogram interpretation. The three most experienced readers achieved substantial to almost perfect intraobserver agreement (kappa, 0.61-1.00) between conventional and MR angiogram interpretation in most cases. Among three readers, moderate agreement (kappa, 0.43-0.53) was found between treatment recommendations based on conventional versus MR angiographic findings; for the most experienced reader, this agreement was almost perfect (kappa, 0.90). CONCLUSION: For experienced readers, there was substantial to almost perfect agreement between conventional and MR angiographic image interpretations of the aorta and lower-extremity arterial system.

Aged↗
PubMed1997

MR imaging of the rotator cuff tendon: interobserver agreement and analysis of interpretive errors.

PURPOSE: To evaluate accuracy in interpretation of shoulder magnetic resonance (MR) images and interobserver agreement and to characterize the types of errors. MATERIALS AND METHODS: Five radiologists with varying experience independently and retrospectively twice interpreted the MR images of 222 symptomatic patients who underwent both MR imaging and shoulder arthroscopy. The first interpretation was a blind review; the second was with knowledge of the arthroscopic findings. RESULTS: For full-thickness tears, the sensitivity, specificity, and accuracy were 84%-96%, 94%-98%, and 92%-97%, respectively, and for partial tears, 35%-44%, 85%-97%, and 77%-87%, respectively. There was no statistically significant difference between readers in the detection of partial or full-thickness tears. There was a statistically significant difference between readers in the no-tear category. Cohen kappa values generally indicated improved interobserver agreement proportional to the readers' experience (full-thickness tears, 0.731-0.881; partial tears, 0.168-0.443). CONCLUSION: Diagnosis of a full-thickness tear can be learned to a high degree of accuracy. Despite the radiologist's level of experience and knowledge of the arthroscopic findings, the sensitivity for diagnosis of partial tears is poor.

Adolescent↗
PubMed1996

Coronal fat suppression fast spin echo images of the knee: evaluation of 202 patients with arthroscopic correlation.

We optimized fat-suppressed fast spin echo (FS-FSE) parameters for coronal imaging of the knee and then evaluated the technique in a clinical setting. Five volunteers and 12 patients were used to evaluate various repetition (TR), echo (TE), and echo train lengths (ETL). Then, 202 patients underwent both knee MR imaging using coronal plane FS-FSE and arthroscopy. The coronal FS-FSE images were compared with radial multiplanar gradient-recalled echo (MPGRE), axial T1-weighted SE, and parasagittal double echo SE images. Proton density images (2,000/19) with an ETL of 2 best depicted the menisci, ligaments, and capsules. The conspicuity of osteochondral abnormalities depicted by the coronal FS-FSE imaging was significantly higher than for axial T1-weighted SE (p < .003) and parasagittal echo SE images (p < .003). The accuracy of the coronal FS-FSE imaging for medial and lateral meniscal tears was 91.6% and 87.6%, respectively. Combined imaging interpretation of the coronal FS-FSE, axial T1-weighted SE, and radial MPGRE imaging improved the accuracy for meniscal tears slightly over any sequence used alone, but the difference was not statistically significant. Fourteen capsular injuries were demonstrated by the coronal FS-FSE imaging. FS-FSE imaging in the coronal plane is a useful complementary sequence in MR examinations of the knee for the evaluation of meniscal tears, capsular injuries, and osteochondral abnormalities.

Adolescent↗
PubMed1995

Multicenter trial to evaluate vascular magnetic resonance angiography of the lower extremity. American College of Radiology Rapid Technology Assessment Group.

OBJECTIVES: To assess the value of magnetic resonance angiography (MRA) in presurgical evaluation of patients with severe lower limb atherosclerotic occlusive disease and to assess the feasibility of rapidly conducting rigorous technology assessment. DESIGN: Blinded, prospective study of consecutive patients with signs or symptoms of severe infrainguinal peripheral vascular disease who were candidates for percutaneous or surgical intervention. Using both descriptive statistics and multivariate logistic analyses, MRA was compared with contrast arteriography (CA) (the current technique) for imaging 15 arterial segments of the leg and foot. Intraoperative contrast angiography was the "gold" standard. Also studied was the effect of adding MRA to the information used in planning treatment. SETTING: Six US hospitals, one a community hospital. PATIENTS: A total of 155; 84% with either rest pain or tissue loss. RESULTS: Sensitivity in distinguishing patent segments from completely occluded segments was 83% for CA and 85% for MRA; both had 81% specificity. For distinguishing near-normal segments (suitable as bypass graft termini), CA was less sensitive than MRA (77% vs 82%), but more specific (92% vs 84%). After adjusting for same-reader effects, odds of correctly distinguishing patent segments were 1.6 times as great for MRA as for CA (P < .01); for distinguishing near-normal segments, the odds for CA were 1.5 times as great as for MRA (P < .05). The addition of MRA changed the treatment plan in 13% of patients; in 86% of these cases, the surgery actually performed indicated that the MRA-inclusive plan was superior. CONCLUSIONS: Individually, MRA and CA are approximately equivalent in diagnostic accuracy. The addition of MRA to treatment plans based only on CA and other diagnostic information clearly improves the plans. Completed in 15 months (as planned), our study demonstrates the feasibility of conducting rigorous technology assessment rapidly enough to be timely even in fields in which diagnostic and treatment techniques are rapidly changing.

Adult↗
PubMed1995

Double-echo three-point-Dixon method for fat suppression MRI.

A double-echo two-excitation pulse sequence encoding fat and water signals for a phase-sensitive three-point Dixon-type analysis (DE-3PD) was developed and implemented on a 1.5 T MR imager. Data processing was performed using a previously developed two-dimensional (2D) region-growing algorithm, adapted to use double-echo data. Density-, T1-, and T2-weighted fat suppression images were obtained from six volunteers using the new fat suppression method. The images were compared with corresponding images obtained using frequency-selective excitation fat suppression (FATSAT) and a single-echo three-point-Dixon method (SE-3PD). The results demonstrate that the DE-3PD sequence shortens the imaging time by one-third compared with the SE-3PD method, without loss in image quality. The data also show that a 2D region-growing algorithm effectively unwraps the phase of DE-3PD data sets, and that results of DE-3PD fat signal suppression are consistently better than those obtained using a standard FATSAT method. The authors conclude that the double-echo sequence provides density-, T1-, and T2-weighted images that appear to be promising for routine clinical applications.

Abdomen↗
PubMed1995

Diagnosis of popliteus injuries with MR imaging.

OBJECTIVE: Popliteal muscle and tendon injuries are thought to be unusual. This report describes the magnetic resonance (MR) appearances of popliteus muscle and tendon injuries. DESIGN AND PATIENTS: The study included 24 patients where the diagnoses of popliteal injuries were prospectively made based on MR appearances. The study group was taken from 2412 consecutive knee MRIs. The injuries were characterized as to involving the muscular or tendinous portions of the popliteus apparatus. RESULTS: In 95.8% (23/24) of patients, the tears of the popliteus involved the muscular portion. The injuries were either partial and interstitial or complete. Three patients had tears of both the muscular and tendinous portions or the tendon alone. The anterior and posterior cruciate ligaments were torn in 16.7% (4/24) and 29.2% (7/24) of patients, respectively. There were medial and lateral meniscal tears in 45.8% (11/24) and 25% (6/24) of patients, respectively. There were injuries of the medial and lateral collateral ligaments in 8.3% (2/24) and 4.2% (1/24) of patients, respectively. Bone bruises and/or fractures were seen in 33.3% (8/24) patients. In 8.3% (2/24) of patients, the popliteus injury was an isolated finding. CONCLUSION: Popliteus muscle and tendon injuries are not uncommon. They usually occur in conjunction with other significant injuries of the knee and can be characterized with MR imaging.

Adolescent↗
PubMed1995

Rotator cuff tendon tears: evaluation with fat-suppressed MR imaging with arthroscopic correlation in 100 patients.

PURPOSE: To evaluate the diagnostic accuracy of fat-suppressed magnetic resonance (MR) imaging of rotator cuff tears in a large symptomatic population. MATERIALS AND METHODS: One hundred patients underwent both MR imaging and arthroscopy of the shoulder. Ninety-two patients underwent fat-suppressed conventional spin-echo MR imaging (repetition time msec/echo time msec = 2,500/20, 60), and eight patients underwent fat-suppressed, fast spin-echo MR imaging (2,000/80). RESULTS: With data combined for complete and partial tears of the rotator cuff (n = 31), MR imaging had an accuracy of 93%; sensitivity, 84%; and specificity, 97%. Seventeen of 20 complete tears and nine of 11 partial tears were properly identified with MR imaging. Two partial tears were not detected and three complete tears were incorrectly called partial tears at MR imaging. Of two false-positive MR imaging findings, one was called a complete tear and the other, a partial tear. CONCLUSION: Fat-suppressed MR imaging has high diagnostic accuracy in evaluating tears of the rotator cuff tendon.

Arthroscopy↗
PubMed1995

Error patterns in the MR imaging evaluation of menisci of the knee.

PURPOSE: To categorize errors in interpretation of magnetic resonance (MR) images of the knee and explain the discrepancy between MR imaging and diagnostic arthroscopic findings. MATERIALS AND METHODS: Five hundred sixty-one patients underwent arthroscopy and MR imaging of the knee. Prospective and retrospective readings were used to categorize tear type and location. Sixty-six patients had 68 discrepancies between MR imaging and arthroscopic findings. RESULTS: Prospective interpretation of MR images of the lateral meniscus had a sensitivity of 82%, specificity of 98%, and accuracy of 93%. For images of the medial meniscus, sensitivity was 96%; specificity, 91%; and accuracy, 95%. The number of diagnostic errors at retrospective analysis was 76% (n = 52) of the number at prospective analysis. CONCLUSION: MR imaging is accurate in evaluation for meniscal tears. Most errors in interpretation that occur at prospective evaluation also occur at retrospective evaluation. Some false-positive errors may be related to incomplete arthroscopic evaluation of the meniscus and confusion between what represents fraying and what represents a tear.

Adult↗
PubMed1995

Lower extremities: MR angiography with a unilateral telescopic phased-array coil.

In a comparison of conventional and magnetic resonance (MR) angiography of the lower extremities, MR imaging was performed with extremity and body coils and a unilateral six-coil telescopic phased-array coil. In one of seven volunteers, average signal-to-noise ratio was 140% higher with the latter (p < .01), only three of five stations were necessary, and examination time was decreased 50%. In the four patients, correlation in findings was 100%.

Adult↗
PubMed1994

Leiomyoma of the seminal vesicle.

Leiomyoma of the seminal vesicle is exceedingly rare, with only a few cases reported in the literature. To our knowledge we present the first case of primary leiomyoma of the seminal vesicle to be evaluated by magnetic resonance imaging using a rectal coil.

Aged↗
PubMed1994

MR imaging of prostate cancer with an endorectal surface coil technique: correlation with whole-mount specimens.

PURPOSE: To evaluate the diagnostic accuracy of magnetic resonance (MR) imaging in staging prostate cancer with an endorectal surface coil technique. MATERIALS AND METHODS: The authors prospectively evaluated MR images obtained with an endorectal surface coil from 70 consecutive patients with known prostate cancer. Gadopentetate dimeglumine was administered to 40 patients. Multiple sequences were used, including conventional and fast spin echo, with and without fat suppression. The readers were blinded to the MR findings unless bone or nodal metastasis was present. MR images were compared with whole-mount sections. RESULTS: The prospective staging accuracy for MR imaging was 51% (36 of 70 patients). Stage B disease was present in 27 patients (38%), stage C in 42 (60%), and stage D in one (1%). The retrospective staging accuracy was 67% (47 of 70 patients). Of the 42 patients with stage C disease, positive surgical margins were present in 36 (85%). Gadopentetate dimeglumine did not help detect or stage tumors. CONCLUSION: Further studies must be performed to determine the role of endorectal coil MR imaging in the staging of prostate cancer.

Aged↗
PubMed1994

Distal biceps tendon injury: MR imaging diagnosis.

PURPOSE: To review the authors' experience with magnetic resonance (MR) imaging of patients with suspected injury of the distal biceps tendon. MATERIALS AND METHODS: Twenty-one patients with clinically suspected injury of the distal biceps tendon were evaluated with MR imaging. Surgical correlation was performed in 15 patients, and long-term clinical follow-up was performed in the remaining six cases. RESULTS: Twelve complete biceps tears, four partial tears, one brachialis rupture, and one ganglion were identified. Axial MR images were more valuable than sagittal images in accurately grading distal biceps tendon injury preoperatively. There was 100% agreement between MR imaging and surgical findings. MR imaging findings led to changes in clinical treatment plans in eight patients (38%). CONCLUSION: MR imaging is useful in the evaluation of patients with suspected distal biceps tendon injury. In particular, axial MR images of the distal biceps insertion are important for accurate grading of the injury.

Adult↗