Biomedical subjects

Laurence Parker

Publications and source records attributed to Laurence Parker.

At least 19 recordsLinked to original sources

PubMed2006

Abnormalities on MRI of the subscapularis tendon in the presence of a full-thickness supraspinatus tendon tear.

OBJECTIVE: Our objective was to determine the association between size and chronicity of full-thickness supraspinatus tendon tears with subscapularis tendon abnormalities on MRI. MATERIALS AND METHODS: One hundred forty-two MRI examinations with full-thickness supraspinatus tendon tears were categorized on the basis of the supraspinatus muscle (SS): normal muscle (SS(normal)), suggesting a recent or small tear; reduced muscle bulk without fatty atrophy (SS(volume loss)); and those with fatty atrophy, suggesting a large or chronic tear (SS(fatty atrophy)). Subscapularis tendon abnormalities, the subcoracoid interval, and subcortical bone marrow edema in the lesser tuberosity and coracoid process were recorded. RESULTS: The mean size of supraspinatus tendon tears in the SS(normal) (n = 45) group was 8.5 mm, 16.6 mm in SS(volume loss) (n = 53), and 29 mm in the SS(fatty atrophy) group (n = 44). Subscapularis tendon abnormality was identified in 22% of SS(normal) patients, 61% of SS(volume loss), and 86% of the SS(fatty atrophy) group (p < 0.001). There was moderate correlation between chronicity of supraspinatus tendon tears and subscapularis tendon abnormality (r = 0.47; p < 0.0001), with no correlation between the subcoracoid interval and abnormalities of the subscapularis tendon. There was moderate correlation between chronicity of supraspinatus tendon tears and bone marrow changes in the lesser tuberosity (r = 0.44; p < 0.0001). CONCLUSION: Subscapularis tendon abnormality is related to chronicity of supraspinatus tendon tears. Bone marrow edema in the lesser tuberosity with a subscapularis tendon abnormality suggests increased stress at the subscapularis tendon insertion with chronicity of full-thickness supraspinatus tendon tears. Lack of correlation with the subcoracoid interval indicates that anterior instability may be a more important contributing factor to subscapularis tendon abnormalities than static subcoracoid impingement in the setting of a full-thickness supraspinatus tendon tear.

Adult↗

PubMed2005

Lateral epicondylitis of the elbow: US findings.

PURPOSE: To determine the sensitivity and specificity of ultrasonography (US) in the detection of lateral epicondylitis and identify the US findings that are most strongly associated with symptoms. MATERIALS AND METHODS: Internal review board approval was obtained for retrospective review of the patient images, and the need for informed consent was waived. Internal review board approval was also obtained for scanning the 10 volunteers, all of whom gave informed consent. The study was compliant with the Health Insurance Portability and Accountability Act. US of the common extensor tendon was performed in 20 elbows in 10 asymptomatic volunteers (six men, four women; age range, 22-38 years; mean age, 29.6 years) and 37 elbows in 22 patients with symptoms of lateral epicondylitis (10 men, 12 women; age range, 30-59 years; mean age, 46 years). Fifty-seven representative images, one from each elbow, were randomly assorted and interpreted by three independent readers who rated each common extensor tendon as normal or abnormal. Abnormal images were further classified as demonstrating one or more of eight US findings. Readers interpreted each image at two separate sessions to determine intrareader variability. The authors calculated the sensitivity and specificity of US in the diagnosis of lateral epicondylitis and the odds ratio for each US finding. Odds ratios were considered statistically significant at P < .05 when 95% confidence intervals did not include one. RESULTS: Sensitivities of US in the detection of symptomatic lateral epicondylitis ranged from 72% to 88% and specificities from 36% to 48.5%. Odds ratios for the following findings were statistically significant (P < .05) for both reading sessions: calcification of common extensor tendon, tendon thickening, adjacent bone irregularity, focal hypoechoic regions, and diffuse heterogeneity. Odds ratios for lateral epicondyle enthesophytes were statistically significant (P < .05) for the first reading session only. Odds ratios for linear intrasubstance tears and peritendinous fluid were not statistically significant. CONCLUSION: US of the common extensor tendon had high sensitivity but low specificity in the detection of symptomatic lateral epicondylitis. The relationship between symptoms and intratendinous calcification, tendon thickening, adjacent bone irregularity, focal hypoechoic regions, and diffuse heterogeneity was statistically significant.

Adult↗

PubMed2005

Reactive endplate marrow changes: a systematic morphologic and epidemiologic evaluation.

PURPOSE: To evaluate the morphology and location of vertebral endplate changes, and to analyze their association with age, gender, and body mass index (BMI). DESIGN AND PATIENTS: At 1.5 T (T1-weighted, T2-weighted/STIR) 100 lumbar spines were evaluated separately by three observers. The readers classified the endplate bone marrow abnormalities on sagittal MR images according to the definitions of Modic et al. Findings were localized by disc segment; whether in the upper and/or lower endplate; and within each endplate divided into 15 segments. Disc space narrowing, as well as disc desiccation, was also noted at each vertebral level. In addition, endplate changes were correlated with age, gender, and BMI (weight(kg)/height(m)2). RESULTS: A total of 15,000 data points were studied and 422 total changes recorded. A total of 99 vertebral levels were affected in 58 patients. Of these, 171 were of type I, 242 were of type II, and 9 were of type III. L4-L5 and L5-S1 vertebral levels were most commonly involved, having (142, 4.73%) and (116, 3.87%) changes respectively (P<0.0001). The upper and lower aspects of the endplate were affected similarly. Changes most frequently occurred at the anterior aspect of the endplate (P<0.0001). Endplate marrow changes were associated with increasing age (P<0.0001) and, surprisingly, male gender (P<0.0001). Endplate changes were not associated with BMI. CONCLUSION: The fatty pattern was most common, with the sclerotic pattern being rare. Endplate marrow changes most often occurred at the anterior aspect of the endplate, particularly at L4--L5 and L5--S1 levels. Modic changes occur more frequently with aging, evidence of their degenerative etiology. They were, however, not related to body habitus, but to weight and male gender.

Adolescent↗

PubMed2004

MRI criteria for patella alta and baja.

OBJECTIVE: To determine the range of the patellar tendon length to patellar length ratio on magnetic resonance imaging (MRI) of the knee in order to aid in the establishment of MRI criteria for patella alta and baja. PATIENTS: Two hundred and forty-five patients ages 6-85 (mean 44) years who went through 262 consecutive 1.5 MRI studies of the knee performed during November 2000 through February 2001 were evaluated, regardless of their clinical symptoms. DESIGN: Patellar length (PL) and patellar tendon length (TL) were measured by a single musculoskeletal radiologist on sagittal images by a line connecting the superior and inferior patellar poles and the shortest length of the inner margin of the tendon respectively. TL/PL ratio was subsequently calculated. The distribution of ratios was evaluated; the extreme 2.5% at each end of the distribution was defined as patella alta and baja. RESULTS: The TL/PL ratio ranged between 0.56 and 1.71 (mean 1.05). After plotting the ratios, we noted an asymmetric curve skewed to the left. Based upon calculation of the extreme 2.5% of the ratio at each end of the plot, we determined that the MRI definition of patella alta and baja is a ratio of TL/PL of more than 1.50 and less than 0.74 respectively. We found that females had significantly higher TL/PL ratio than males (1.0878 and 1.0032 respectively). Ratios defined for patella alta and baja were 1.52 and 0.79 respectively in females and 1.32 and 0.74 respectively in males ( p<0.0001). CONCLUSION: Patella alta and baja are determined as TL/PL of more than 1.50 and less than 0.74 respectively, somewhat different than traditionally quoted radiographic and previously described MRI criteria.

Adolescent↗

PubMed2004

Trends in utilization: has extremity MR imaging replaced diagnostic arthroscopy?

OBJECTIVE: To examine the relative change in utilization of magnetic resonance (MR) imaging of the extremities versus diagnostic and therapeutic arthroscopy. DESIGN AND PATIENTS: Using the 1993, 1996, and 1999 nationwide Medicare Part B databases, utilization rates (per 100000) were determined for upper and lower extremity MR imaging, diagnostic arthroscopy and therapeutic arthroscopy using CPT-4 codes. Utilization of extremity MR imaging was compared with that of diagnostic and therapeutic arthroscopy in 10 geographic regions of the United States and tracked over time. RESULTS: Combined lower and upper extremity MR imaging utilization per 100000 increased from 393 to 1056 in 1999 (+168.7%). Utilization of diagnostic arthroscopy of the extremities decreased from 18 in 1993 to 8 in 1999 (-55.6%); therapeutic arthroscopy rates increased from 461 in 1993 to 636 in 1999 (+40.0%). Specifically, from 1993 to 1999, utilization of lower extremity MR imaging increased from 270 to 661 (+144.8%). Utilization of diagnostic arthroscopy of the knee over the same time period decreased from 11 to 5 (-54.5%); therapeutic arthroscopy increased from 394 to 501 (+27.2%). Similarly, utilization rates for upper extremity MR imaging increased from 123 to 395 (+221.1%). Utilization of diagnostic arthroscopy of the shoulder over the same time period decreased from 7 to 2 (-71.4%); therapeutic arthroscopy increased from 44 to 104 (+136.4%). No specific geographic trends were ascertained. CONCLUSION: The utilization of MR imaging of the extremities has markedly increased from 1993 to 1999. During the same time period the utilization of diagnostic arthroscopy has decreased and that of therapeutic arthroscopy has increased. These findings support the hypothesis that there is increased reliance of clinical practitioners on the diagnostic information provided by MR imaging in preoperative clinical decision-making.

Aged↗

PubMed2004

Angiographic assessment of initial balloon angioplasty results.

PURPOSE: To determine the influence of three factors involved in the angiographic assessment of balloon angioplasty-interobserver variability, operator bias, and the definition used to determine success-on the primary (technical) results of angioplasty in the peripheral arteries. MATERIALS AND METHODS: Percent stenosis in 107 lesions in lower-extremity arteries was graded by three independent, experienced vascular radiologists ("observers") before and after balloon angioplasty and their estimates were compared with the initial interpretations reported by the physician performing the procedure ("operator") and an automated quantitative computer analysis. Observer variability was measured with use of intraclass correlation coefficients and SD. Differences among the operator, observers, and the computer were analyzed with use of the Wilcoxon signed-rank test and analysis of variance. For each evaluator, the results in this series of lesions were interpreted with three different definitions of success. RESULTS: Estimation of residual stenosis varied by an average range of 22.76% with an average SD of 8.99. The intraclass correlation coefficients averaged 0.59 for residual stenosis after angioplasty for the three observers but decreased to 0.36 when the operator was included as the fourth evaluator. There was good to very good agreement among the three independent observers and the computer, but poor correlation with the operator (P </= .001). The primary success rates for this series of lesions varied from a low of 47% to high of 99%, depending solely on which definition of success was used. Significant differences among the operator, the three observers, and the computer were not present when the definition of success was based on less than 50% residual stenosis. CONCLUSIONS: Observer variability and bias in the subjective evaluation of peripheral angioplasty can have a significant influence on the reported initial success rates. This effect can be largely eliminated with the use of residual stenosis of less than 50% to define success. Otherwise, meaningful evaluation of angioplasty results will require independent panels of evaluators or computerized measurements.

Analysis of Variance↗

PubMed2004

Diagnosing breast lesions with contrast-enhanced 3-dimensional power Doppler imaging.

OBJECTIVE: To compare mammography with contrast-enhanced 2- and 3-dimensional power Doppler imaging for the diagnosis of breast cancer. METHODS: Fifty-five patients, who underwent breast biopsies with histopathologic assessment, participated in a study of mammography and contrast-enhanced sonography. Levovist (Berlex Laboratories, Montville, NJ) and Optison (Mallinckrodt, St Louis, MO) were administrated to 22 and 33 patients, respectively. Precontrast and postcontrast 2-dimensional power Doppler data of the lesion were obtained with an HDI 3000 system (Philips Medical Systems, Bothell, WA), and 3-dimensional data were acquired with an LIS 6000A system (Life Imaging Systems Inc, London, Ontario, Canada). Two independent and blinded readers assessed diagnosis. Receiver operating characteristic curves were computed individually and in combination for mammography and 2- and 3-dimensional sonography (before and after contrast). Histopathologic and imaging parameters were compared by Mann-Whitney statistics. RESULTS: Mammographic findings were available for 50 patients, biopsy for 54, and 2- and 3-dimensional sonographic images for 53 and 52, respectively. Of the 50 patients who had all 4 measures, 15 (30%) had malignancies. The areas under the receiver operating characteristic curve for the diagnosis of breast cancer were 0.51 for 2-dimensional contrast-enhanced imaging, 0.60 for 3-dimensional power Doppler imaging, and 0.76 for 3-dimensional contrast-enhanced imaging (P < .01). Mammography produced an area of 0.86, which increased when combined with 3-dimensional contrast-enhanced imaging to 0.90 and with all sonographic modalities to 0.96 (P < .001). The histopathologic diagnosis of benign or malignant correlated with the presence or absence of anastomoses and with the degree of vascularity assessed with contrast-enhanced 3-dimensional power Doppler imaging (P = .007 and .02). CONCLUSIONS: Contrast-enhanced 3-dimensional power Doppler imaging increases the ability to diagnose breast cancer relative to conventional 2- and 3-dimensional sonographic imaging.

Adult↗

PubMed2003

MR imaging of anterior cruciate ligament tears: is there a gender gap?

OBJECTIVE: Clinically, females receive anterior cruciate ligament (ACL) tears more commonly than males. We explored whether gender differences exist in MR imaging patterns of ACL tears. DESIGN AND PATIENTS: At 1.5 T, two observers evaluated MR examinations of 84 consecutive age-matched patients (42 males, 42 females, aged 16-39) with ACL tears, for mechanism of injury, extent and type of tear, the presence of secondary signs and associated osseous, meniscal and ligamentous injuries. RESULTS: The most common mechanism of injury for both females and males was the pivot shift mechanism (67 and 60%, respectively). Females were more commonly imaged in the acute stage of tear than males (98 and 67%, respectively, p=0.001) and more commonly possessed the typical posterolateral tibial bone contusion pattern (88 and 62%, respectively, p=0.0131). Males exhibited a deeper femoral notch sign (2.7 and 2.0 mm, p=0.007) and medial meniscal, lateral collateral ligament and posterior cruciate ligament injuries more commonly than females (48 and 24%, p=0.009, 30 and 7%, p=0.035, 17 and 0%, p=0.035). There was no significant difference between genders for the presence of other secondary signs and contusion patterns, associated lateral meniscal tears, presence of O'Donoghue's triad or associated medial collateral ligament injuries. CONCLUSION: Gender differences in MR imaging patterns of ACL tears exist: females are more commonly imaged in the acute stage and more commonly possess posterolateral tibial bone contusions; males have a more severe presentation than females, associated with more severe lateral femoral condyle and soft tissue injuries.

Acute Disease↗

PubMed2003

Suspected early or mild chronic pancreatitis: enhancement patterns on gadolinium chelate dynamic MRI. Magnetic resonance imaging.

PURPOSE: To assess whether measuring the pattern of pancreatic enhancement on gadolinium chelate dynamic magnetic resonance imaging (MRI) is helpful for diagnosis of suspected early or mild chronic pancreatitis. MATERIALS AND METHODS: In this retrospective study, 24 patients with suspected early or mild chronic pancreatitis, classified by imaging criteria of equivocal chronic pancreatitis (ultrasound, computed tomography [CT] or ERCP) grading, had dynamic MRI that included unenhanced, arterial dominant, early venous, and late venous phases of contrast enhancement. Twenty patients without pancreatic diseases also had the dynamic sequence as a control group. The signal intensity was measured at the pancreatic head, body, and tail on all phases, and for each, the signal intensity ratio (SIR, the signal intensity in postcontrast divided by that in precontrast) was calculated. Two radiologists independently reviewed the images of the patients with suspected early or mild chronic pancreatitis for pancreatic morphologic abnormalities without knowing the results of signal intensity measurements. RESULTS: On unenhanced images, there was no significant difference of signal intensity between control and pancreatitis groups (P < 0.05). In the pancreatitis group, but not in the control group, the unenhanced signal intensity of the pancreatic head and body were significantly higher than that of the tail (P < 0.05). In the control group, the greatest enhancement (highest SIR) after injection was in the arterial phase (1.89 +/- 0.31), significantly higher than that in the early venous phase (1.68 +/- 0.17, P < 0.01) and in the late venous phase (1.61 +/- 0.15, P < 0.001). The pancreatitis group, however, had an arterial phase SIR (1.65 +/- 0.23) that was significantly lower than its early venous phase SIR (1.75 +/- 0.22, P < 0.05) and lower than the arterial phase SIR of the control group (P < 0.01). The presence of an SIR less than 1.73 in the arterial phase and/or a delayed peak enhancement after contrast agent administration had a sensitivity and specificity of diagnosing early or mild chronic pancreatitis of 92% and 75%, respectively. This sensitivity was significantly higher than the sensitivity of 50% for diagnosis based on morphologic abnormalities (P < 0.05). CONCLUSION: Measuring pancreatic signal intensity on gadolinium chelate dynamic MRI is helpful for diagnosing early or mild chronic pancreatitis, especially before apparent pancreatic morphologic or signal intensity changes are present.

Adult↗

PubMed2003

Functional magnetic resonance cholangiography (fMRC) of the gallbladder and biliary tree with contrast-enhanced magnetic resonance cholangiography.

PURPOSE: To determine the diagnostic performance of functional magnetic resonance cholangiography (fMRC) for the evaluation of anatomic and functional biliary disorders. MATERIALS AND METHODS: At 1.5 T, 39 MR examinations with conventional MRC and mangafodipir trisodium-enhanced fMRC were retrospectively reviewed by three observers who recorded anatomic (duct dilation, stricture, filling defects) and functional (cholecystitis, obstruction) abnormalities in three modes: MRC alone, fMRC alone, and MRC and fMRC images together (combined-MRC). Performance was determined by comparing findings with each mode to findings of invasive cholangiography (IC) and surgery. RESULTS: Among 75 biliary segments (correlated with IC), the sensitivity/specificity for diagnosing dilation (N = 41) with MRC was 95%/97%; with fMRC, 90%/100%; with combined-MRC, 100%/97%. For stricture (N = 7), the sensitivity/specificity of MRC was 86%/98%; of fMRC, 43%/100%; of combined-MRC, 86%/100%. For filling defects (N = 9), the sensitivity/specificity of MRC was 91%/98%; of fMRC, 82%/100%; of combined-MRC, 91%/100%. For diagnosing obstruction (N = 9), the sensitivity/specificity of MRC, fMRC, and combined-MRC were 89%/100%, 100%/100%, and 100%/100%, respectively. For surgically proven cholecystitis (N = 13), positive predictive values for diagnosing acute/chronic cholecystitis for MRC were 33%/40%; for fMRC, 100%/50%; for combined-MRC, 100%/50%. CONCLUSION: Although single-shot fast spin echo (SSFSE)-MRC is valuable, the addition of fMRC increased diagnostic performance for functional biliary disorders.

Biliary Tract↗

PubMed2003

Nationwide trends in rates of utilization of noninvasive diagnostic imaging among the Medicare population between 1993 and 1999.

PURPOSE: To determine current utilization rates and recent nationwide trends for noninvasive diagnostic imaging (NDI) among the Medicare population. MATERIALS AND METHODS: Medicare Part B claims data files from 1993, 1996, and 1999 were analyzed for all procedure codes related to NDI. NDI codes were grouped into 22 imaging categories, as well as seven imaging modality groups. The data were analyzed to determine the overall nationwide utilization and relative value unit (RVU) volume and rates and changes in utilization rates and RVU rates between 1993 and 1999 for the Medicare fee-for-service population, which included approximately 33 million enrollees per year. RESULTS: The overall utilization rate for all NDI in 1999 was 324,974 examinations per 100,000 enrollees. Conventional radiography was the most utilized imaging technology (55.5%), followed by ultrasonography (US) (20.5%), computed tomography (CT) (8.8%), mammography (6.0%), nuclear imaging (5.2%), magnetic resonance (MR) imaging (2.6%), and bone densitometry (1.5%) (percentages do not add up to 100% due to rounding). In the 6-year interval from 1993 to 1999, the rate of NDI utilization increased 3.8%. The utilization rate for conventional radiography decreased 13.7%, while that of all other modalities increased a combined total of 39.1%. During this 6-year period, RVU rates per 100,000 increased 14.6%, with RVUs for MR imaging increasing 76.6%; those for nuclear imaging, 38.7%; those for CT, 28.3%; and those for US, 24.2%. CONCLUSION: A 3.8% increase in the rate of NDI utilization occurred during the 6-year period between 1993 and 1999. A considerably larger increase in RVU rates (14.6%) occurred during the same time period.

Diagnostic Imaging↗

PubMed2003

Practice patterns of radiologists and nonradiologists in utilization of noninvasive diagnostic imaging among the Medicare population 1993-1999.

PURPOSE: To compare nationwide trends in noninvasive diagnostic imaging (NDI) practice patterns of radiologists and of nonradiologists among the Medicare population during the 6 years from 1993 to 1999. MATERIALS AND METHODS: Medicare Part B claims files from 1993, 1996, and 1999 were analyzed for all procedure codes related to NDI. NDI codes were classified into 22 diagnostic categories within seven imaging modality groups. For each NDI code, physicians performing the services were classified as radiologists or nonradiologists by using the provider specialty code designated in claims in the files. The data were analyzed to determine the overall utilization rates and relative value unit (RVU) rate changes between 1993 and 1999 among radiologists and nonradiologists. RESULTS: In 1993, the overall NDI utilization rate per 100,000 Medicare fee-for-service beneficiaries was 215,652 for radiologists and 79,942 for nonradiologists. In 1999, the rate was 207,270 for radiologists and 100,059 for nonradiologists, which is a 3.9% decrease among radiologists and a 25.2% increase among nonradiologists. In the 6-year interval from 1993 to 1999, the overall RVU rate increased 6.9% among radiologists and 32.4% among nonradiologists. The percentage of NDI performed by radiologists decreased from 73.0% in 1993 to 67.4% in 1999. CONCLUSION: Overall, the utilization rate of advanced, high-technology imaging is increasing among both radiologists and nonradiologists. However, it is increasing at a considerably more rapid rate among nonradiologists.

Diagnostic Imaging↗

PubMed2003

MR imaging of the lumbar spine: relation of posterior soft-tissue edema-like signal and body weight.

OBJECTIVE: Our purpose was to determine the association between posterior lumbar spine subcutaneous edema, fluid collections, and body weight on lumbar spine MR imaging. MATERIALS AND METHODS: MR images of the lumbar spine obtained at 1.5 T of 307 consecutive outpatients (191 female, 116 male) were reviewed on the basis of MR imaging signal characteristics for the presence, degree, size, and location of presumed subcutaneous posterior soft-tissue edema and fluid collections. The patients were divided into three weight groups (<70, 70-85, or > 85 kg) and two age groups (<50 or >/=50 years old). Edema was graded on a scale of 0-5 according to its length relative to the vertebral bodies. When present, the fluid collection volumes were calculated. The vertical epicenter of the signal abnormality was noted by vertebral body level. RESULTS: Lumbar soft-tissue edema was seen in 121 patients (39%), and discrete fluid collections were seen in 53 patients (17%). Both degree of edema and volume of fluid collection were associated with increasing weight (p < 0.001 and p = 0.002, respectively) and increasing age (p < 0.001 and p = 0.01, respectively). The degree of edema in females was significantly greater than in males (p = 0.003). However, the sex of the patient did not correlate with frequency of fluid collections (p = 0.12) or volume of collections (p = 0.08). The mean epicenters of edema in females and males were at similar levels (L3.4 and L3.9, respectively, p = 0.54). CONCLUSION: The severity of posterior lumbar subcutaneous edema and the volume of fluid collections on MR imaging are associated with increased weight.

Adolescent↗

PubMed2002

Recent rapid increase in utilization of radionuclide myocardial perfusion imaging and related procedures: 1996-1998 practice patterns.

PURPOSE: To evaluate cardiac nuclear medicine practice patterns in different physician specialty groups to better understand a recent rapid increase in utilization of radionuclide myocardial perfusion imaging (MPI) and certain supplementary examinations. MATERIALS AND METHODS: National Medicare Part B databases from 1996 and 1998 were used to evaluate utilization of four primary procedure codes for radionuclide MPI and two supplementary codes (add-on left ventricular wall motion or left ventricular ejection fraction). Utilization rates were calculated for cardiologists, radiologists, and other physicians. Other cardiac imaging for which radionuclide imaging might be substituted was similarly studied. RESULTS: Overall utilization rate of radionuclide MPI per 100,000 Medicare beneficiaries increased 19.1%, from 4,046 in 1996 to 4,820 in 1998 (P <.001). However, for cardiologists the rate increased from 1,771 to 2,413 (36.3%), whereas for radiologists it increased from 1,958 to 2,031 (3.7%) (P <.001 for both changes). Overall utilization rate of add-on codes increased 264% from 1,006 to 3,657 (P <.001). By 1998, the ratio of these add-on examinations to primary MPI was 0.94 among cardiologists compared with 0.53 among radiologists (relative risk, 1.77; 95% CI: 1.76, 1.78). Cardiologist-performed stress echocardiography and cardiac catheterization and coronary angiography increased by 24.2% and 8.7%, respectively. CONCLUSION: Growth in utilization of radionuclide MPI between 1996 and 1998 was almost 10 times higher among cardiologists than radiologists. Utilization of the two add-on codes increased even more dramatically. The greater use of MPI is not a substitute for other cardiac imaging.

Cardiac Catheterization↗

PubMed2002

Trends in the utilization of MR angiography and body MR imaging in the US Medicare population: 1993-1998.

PURPOSE: To determine the trends in utilization of non-neurologic (ie, body) magnetic resonance (MR) imaging and of MR angiographic examinations performed from 1993 to 1998, the trends in non-radiologist participation in MR imaging, and the relative reimbursements for these examinations compared with those for all other noninvasive imaging studies performed in 1998. MATERIALS AND METHODS: By using the 1993, 1996, and 1998 nationwide Medicare Part B databases, utilization rates per 100,000 Medicare beneficiaries and physician reimbursements were determined for seven MR angiography and 14 body MR imaging CPT-4 (Current Procedural Terminology, version 4) codes. Medicare specialty codes were used to categorize physicians as radiologists or non-radiologists. RESULTS: The utilization rate per 100,000 Medicare beneficiaries for all 21 MR angiography and body MR imaging codes increased from 649 in 1993 to 1,253 in 1996 and to 1,876 in 1998--a 189% increase. These rates represented 0.55% of the total noninvasive imaging volume in 1998 and 2.8% of physician reimbursements. Musculoskeletal MR imaging utilization increased 142% from 1993 to 1998 compared with a 58% increase in the utilization of other body MR imaging studies. Non-radiologist participation in musculoskeletal MR imaging increased from 2.9% in 1993 to 3.6% in 1996 and to 5.6% in 1998. CONCLUSION: MR angiography and body MR imaging utilization rates increased substantially from 1993 to 1998. However, these studies still account for a minor fraction of all noninvasive imaging examinations performed and fees reimbursed. MR angiography and musculoskeletal MR imaging utilization has increased rapidly. Non-radiologist participation in musculoskeletal MR imaging is increasing.

Aged↗

PubMed2002

Pancreatic cysts: depiction on single-shot fast spin-echo MR images.

PURPOSE: To evaluate single-shot fast spin-echo (SE) magnetic resonance (MR) imaging for depiction of pancreatic cysts in a large number of patients and to analyze cyst prevalence with respect to patient age and sex and other clinical information. MATERIALS AND METHODS: Single-shot fast SE images of the pancreas were obtained in 1,444 patients. The images were reviewed for presence of pancreatic cysts, which were classified as simple and nonsimple types, and cyst diameters were measured. kappa statistic, Fisher exact, McNemar Q, and Pearson product moment correlation tests were performed. RESULTS: Two hundred eighty-three (19.6%) patients had at least one pancreatic cyst. The prevalence of pancreatic cysts increased with age (r = 0.96). The percentages of male and female patients with pancreatic cysts (20.4% vs 18.8%) were not significantly different. Two hundred seventy-one (18.8%) patients had simple cysts, and 147 (10.2%) had nonsimple cysts. Of 283 patients with pancreatic cysts, 158 (55.8%) had only one pancreatic cyst. The number of patients with multiple cysts increased with age after 70 years. Four hundred fifteen (83.8%) cysts were 10 mm in diameter or smaller; 56 (11.3%), 11-20 mm in diameter; and 24 (4.9%), 21 mm in diameter or larger. Sixteen (5.7%) patients with pancreatic cysts had malignant pancreatic tumors, and 75 (26.5%) patients had pancreatitis. CONCLUSION: The prevalence of pancreatic cysts at single-shot fast SE MR imaging-especially cysts with a diameter smaller than 10 mm-is similar to that of pancreatic cysts at autopsy and higher than that of pancreatic cysts at transabdominal ultrasonography. Prevalence is especially high in patients with pancreatitis.

Adolescent↗

PubMed2002

Spinal injection procedures: volume, provider distribution, and reimbursement in the U.S. medicare population from 1993 to 1999.

PURPOSE: To evaluate spinal injection procedures for trends in volume, reimbursement, and physician specialty participation. MATERIALS AND METHODS: By using the 1993, 1996, 1998, and 1999 Medicare Part B claims database, we studied Current Procedural Terminology revision 4 codes used for percutaneous spinal injection procedures, including cervical and lumbar discography, disk aspiration and/or injection, facet and/or perifacet joint injection, and epidural steroid injection. For each of these procedures, volume, reimbursement, and physician specialty participation (categorized as radiology, anesthesiology, surgery, physiatry, and other specialties) for each year were recorded. RESULTS: Despite an overall increase in spinal injection procedure volume and reimbursement from 1993 to 1999, nonradiologists performed most of these procedures. Epidural steroid and facet joint injections had the highest volume and reimbursement during this time period and were performed almost exclusively by nonradiologists (predominantly anesthesiologists). Radiologists performed more discography procedures than did other specialists in 1993, but participation decreased each year, while anesthesiologist participation increased; as of 1999, anesthesiologists performed more discography procedures than did radiologists. Although radiologists performed more disk aspiration procedures than did other specialists, procedure volume remained low during the period studied. CONCLUSION: Spinal injection volume and reimbursement have increased substantially in the Medicare population from 1993 to 1999. During this interval, radiologist participation has decreased. Nonradiologists perform most spinal injection procedures.

Humans↗

PubMed2002

Cardiovascular imaging: who does it and how important is it to the practice of radiology?

OBJECTIVE: Our research was conducted to ascertain the importance of noninvasive cardiovascular imaging to the practice of radiology and to determine what percentages of noninvasive cardiovascular imaging are performed by radiologists and by other types of physicians. MATERIALS AND METHODS: Using the national 1998 Medicare Part B database, we reviewed all 460 procedure codes pertaining to noninvasive diagnostic imaging and identified 65 that were specifically related to the cardiovascular system. These 65 codes were grouped in five categories: cardiac MR imaging, MR angiography, cardiovascular nuclear medicine, echocardiography, and vascular sonography. For each code and category, we determined the nationwide examination volume, the utilization rate per 1,000 Medicare fee-for-service enrollees, Part B physician reimbursements, and the percentages of examinations performed by radiologists, cardiologists, surgeons, and other physicians. RESULTS: During 1998, 19,244,001 noninvasive cardiovascular imaging studies were performed on Medicare enrollees, which accounted for 17.7% of all Medicare diagnostic imaging studies carried out that year and 33.6% of all Part B imaging-related reimbursements paid. The utilization rate for noninvasive cardiovascular imaging was 603 per 1,000 Medicare enrollees per year. Echocardiography alone accounted for 63.4% of these examinations. Radiologists conducted 16.7% of all noninvasive cardiovascular imaging, whereas cardiologists conducted 61.5%, surgeons 4.8%, and other physicians 16.9% of the examinations. The strong role of cardiologists was largely attributable to their dominance in echocardiography. Radiologists had a substantial role in all categories except echocardiography. CONCLUSION: Noninvasive cardiovascular imaging represents an important component of the practice of radiology. Radiologists have substantial participation in all aspects of the field with the exception of echocardiography.

Diagnostic Techniques, Cardiovascular↗