Individual magnetic resonance imaging and radiographic features of knee osteoarthritis in subjects with unilateral knee pain: the health, aging, and body composition study.

OBJECTIVE: Strong associations between radiographic features of knee osteoarthritis (OA) and pain have been demonstrated in persons with unilateral knee symptoms. This study was undertaken to compare radiographic and magnetic resonance imaging (MRI) features of knee OA and assess their ability to discriminate between painful and nonpainful knees in persons with unilateral symptoms. METHODS: The study population included 283 individuals ages 70-79 years with unilateral knee pain who were enrolled in the Health, Aging, and Body Composition Study, a study of weight-related diseases and mobility. Radiographs of both knees were read for Kellgren/Lawrence (K/L) grade and individual radiographic features, and 1.5T MRIs were assessed using the Whole-Organ Magnetic Resonance Imaging Score. The association between structural features and pain was assessed using a within-person case-control design and conditional logistic regression. Receiver operating characteristic (ROC) analysis was then used to test the discriminatory performance of structural features. RESULTS: In conditional logistic analyses, knee pain was significantly associated with both radiographic features (any joint space narrowing grade ≥ 1) (odds ratio 3.20 [95% confidence interval 1.79-5.71]) and MRI features (any cartilage defect scored ≥ 2) (odds ratio 3.67 [95% confidence interval 1.49-9.04]). However, in most subjects, MRI revealed osteophytes and cartilage and bone marrow lesions in both knees, and using ROC analysis, no individual structural feature discriminated well between painful and nonpainful knees. The best-performing MRI feature (synovitis/effusion) was not significantly more informative than K/L grade ≥ 2 (P = 0.42). CONCLUSION: In persons with unilateral knee pain, MRI and radiographic features were associated with knee pain, confirming that structural abnormalities in the knee have an important role in the etiology of pain. However, no single MRI or radiographic finding performed well in discriminating between painful and nonpainful knees. Further work is needed to examine how structural and nonstructural factors influence knee pain.

What semi-quantitative scoring instrument for knee OA MRI should you use?

Multiple techniques have been used to assess synovial morphology and change on MRI in OA. Broadly speaking these methods are divided into quantitative and semi-quantitative methods. Quantitative measurements use computer-aided image processing to assess joint quantification (cartilage morphometry, bone volume, bone marrow lesion volume, meniscal position and volume, synovial volume, etc). In contrast to quantitative measures, semi-quantitative image analysis is typically much more observer dependent and generates grades or scales rather than truly continuous output. Multiple methods for semi-quantitative multi-feature assessment of the knee using conventional MRI acquisitions exist. These instruments provide for broad assessment of the whole joint and derive from knowledge from reading as to what joint features are morphologically abnormal. They are labour- and expertise-intensive compared to more automated methodologies. As a consequence of their reader dependence, precision and reliability results have not been as favourable for these instruments as their quantitative cousins. These instruments are generally based on past perceptions of what should be considered an important feature and therefore can bias future research. This said they do provide an important tool especially when quantitative methodologies are lacking or have their own inherent limitations.

Follicular non-Hodgkin's lymphoma.

Follicular non-Hodgkin's lymphoma (NHL) is a unique subtype of NHL, which is indolent, incurable with a high prevalence of residual mass after treatment, and may transform to more aggressive NHL. The aim of this review is to (1) describe the histological and flow cytometry characteristics of follicular NHL; (2) introduce the Follicular Lymphoma International Prognostic Index 2 (FLIPI-2), which allows better treatment selection and patient stratification for clinical trials; (3) illustrate the classic and atypical ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and positron-emission tomography (PET)/CT appearance of follicular NHL; and (4) characterize the appearance of nodal and extranodal follicular NHL with pathological correlation. Imaging is essential in every step of the management of patients with follicular lymphoma. Overall survival is improved with better predictive tools and new targeted biological therapies. Radiologists should be aware of possible active residual mass, indolent recurrence, transformation, and association with other primary cancers in patients treated for follicular lymphoma.

Flocculation monitoring of wastewater by using impedance spectroscopy.

The aim of the present work is to monitor the flocculation process using the analysis of the electric and dielectric properties. Therefore the dielectric and electrical characteristics of wastewater with different cationic polymer concentrations were investigated via the impedance spectroscopy (IS) method. Impedance measurements were carried at different concentration of cationic polymer in the frequency range from 0.1 Hz to 100 kHz. The analysis of complex permittivity spectra was described by the superposition of a power law at a low frequency related to the diffusion process and Cole-Cole relaxation behavior at high frequency. Moreover, an equivalent circuit model was developed in order to analyze the experimental data and to further investigate both processes. The variation of the parameters extracted from the equivalent circuit with the increase of cationic polymer concentrations has shown a net transition at 10 mg/l. This behavior could reflect the flocculation of dispersed particles at 10 mg/l. The findings in this work could draw new attention toward the monitoring of the coagulation-flocculation process using impedance spectroscopy and could be extended to other kinds.

Indecainide compared with quinidine for chronic stable ventricular arrhythmias secondary to coronary artery disease or to cardiomyopathy.

Indecainide, a new type Ic antiarrhythmic agent, and quinidine sulfate were compared in a randomized double-blind parallel study. Cardiac patients with greater than or equal to 30 ventricular premature complexes per hour hour received indecainide, 50 mg, or quinidine, 200 mg every 6 hours, and the doses were increased until more than 80% suppression was noted, adverse effects occurred or a maximal dose of 100 mg of indecainide or 400 mg of quinidine given every 6 hours. Efficacy was achieved in 8 of 10 taking indecainide (p less than 0.05) and 7 of 9 taking quinidine (p less than 0.05). At least 90% of episodes of ventricular tachycardia were suppressed in 4 of 7 patients taking indecainide and 1 of 4 taking quinidine. No adverse effects were observed in the 7 patients who responded to indecainide and the 4 who responded quinidine, resulting in short-term efficacy without adverse effects in 7 patients (70%) taking indecainide and 4 (44%) taking quinidine. The effective or maximal mean daily indecainide and quinidine doses were 190 +/- 32 mg and 1,022 +/- 291 mg, respectively; mean trough indecainide and quinidine concentrations were 617 +/- 247 ng/ml and 3.3 +/- 1.4 micrograms/ml, respectively. Indecainide prolonged mean PR and QRS intervals (p less than 0.05), but not QT and QTc intervals. Quinidine did not change PR or QRS intervals but prolonged QTc interval (p less than 0.05). During dosing, 1 patient discontinued indecainide treatment because of nausea; 3 discontinued quinidine because of gastrointestinal complaints.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of cycle lengths between induced and spontaneous sustained ventricular tachycardia during concordant antiarrhythmic therapy associated with healed myocardial infarction.

We propose that in clinical practice, whenever possible, the VT detection interval should be selected by adding >60 ms to the induced maximal VT cycle length in order to ensure a high sensitivity for the detection of future spontaneous VT episodes.

Neural network based automated algorithm to identify joint locations on hand/wrist radiographs for arthritis assessment.

Arthritis is a significant and costly healthcare problem that requires objective and quantifiable methods to evaluate its progression. Here we describe software that can automatically determine the locations of seven joints in the proximal hand and wrist that demonstrate arthritic changes. These are the five carpometacarpal (CMC1, CMC2, CMC3, CMC4, CMC5), radiocarpal (RC), and the scaphocapitate (SC) joints. The algorithm was based on an artificial neural network (ANN) that was trained using independent sets of digitized hand radiographs and manually identified joint locations. The algorithm used landmarks determined automatically by software developed in our previous work as starting points. Other than requiring user input of the location of nonanatomical structures and the orientation of the hand on the film, the procedure was fully automated. The software was tested on two datasets: 50 digitized hand radiographs from patients participating in a large clinical study, and 60 from subjects participating in arthritis research studies and who had mild to moderate rheumatoid arthritis (RA). It was evaluated by a comparison to joint locations determined by a trained radiologist using manual tracing. The success rate for determining the CMC, RC, and SC joints was 87%-99%, for normal hands and 81%-99% for RA hands. This is a first step in performing an automated computer-aided assessment of wrist joints for arthritis progression. The software provides landmarks that will be used by subsequent image processing routines to analyze each joint individually for structural changes such as erosions and joint space narrowing.

Ictal bradycardia in a young child with focal cortical dysplasia in the right insular cortex.

We report on a three and a half year old child with episodic sinus bradycardia during habitual seizures and prolonged interictal discharges due to focal cortical dysplasia in the anterior 2/3 of the insula and the inferior frontal cortex. Seizure-induced bradycardia is rarely reported in children. Bradycardia is suspected to be related to sudden death, a rare complication of a chronic seizure disorder. Several well-documented cases in adult patients reveal a high incidence of temporal epilepsy, but MRI and PET studies in healthy subjects suggest a major role of the insular cortex, especially the right, in cardiac regulation. Our finding underlines the predominance of the right insula in cardiac control, which already seems to be present in children.

Temporal lobe epilepsy and postural orthostatic tachycardia syndrome (POTS).

We describe a 20-year-old woman suffering from right temporal epilepsy, behavioral disorder, and a complaint of paroxysmal palpitations accompanied by anxiety. Detailed cardiac evaluation revealed that the palpitations were due to episodes of marked sinus tachycardia secondary to a concomitant postural orthostatic tachycardia syndrome (POTS) and not of psychogenic origin as initially thought. Treatment with a beta-blocker resulted in the disappearance of palpitations and the associated anxiety. This is the first report of the coexistence of partial epilepsy and POTS. The recognition of such a syndrome in epileptic patients is important in order to offer appropriate therapy.

Bifenthrin: a useful pyrethroid insecticide for treatment of mosquito nets.

Bifenthrin, a pyrethroid insecticide already used in agriculture was evaluated in laboratory conditions against susceptible and pyrethroid resistant mosquitoes, as a potential insecticide for treatment of mosquito nets. Two laboratory strains of Anopheles gambiae s.s. Giles, the major malaria vector in Africa, and two of Culex quinquefasciatus Say, a major pest mosquito in urban areas, were used. Compared with other pyrethroids such as permethrin and deltamethrin, the intrinsic toxicity of bifenthrin, measured by topical application with susceptible strains, was intermediate. By forced tarsal contact on filter papers (cylinder tests) or on netting materials (cone tests), bifenthrin was found slightly more effective against A. gambiae than against C. quinquefasciatus, in terms of mortality and knock-down effect. With free flying mosquitoes (tunnel tests), bifenthrin was very efficient in killing mosquitoes and inhibiting blood feeding. Against the two pyrethroid resistant strains, bifenthrin was relatively efficient against A. gambiae but the impact of resistance was greater with C. quinquefasciatus. In tunnel tests, blood feeding remained almost entirely inhibited with the two species despite resistance. The high mortality of susceptible mosquitoes and excellent blood feeding inhibition of susceptible and resistant strains makes bifenthrin a good candidate for treatment of netting materials, particularly in areas where C. quinquefasciatus, the main nuisance in urban areas, is resistant to pyrethroids. The slower knock-down and lower irritant effect also makes this insecticide especially attractive when a mass killing effect on mosquito populations is expected.

Perioperative complications of cardioverter-defibrillator implantation: the Emory experience.

Over a 5-year period, 110 cardioverter-defibrillators (109 epicardial, 1 transvenous) were implanted consecutively in selected patients with ventricular tachyarrhythmias. The perioperative course of this patient population was examined to determine the associated morbidity and mortality of the procedure. Patients were predominantly male, with coronary artery disease and a decreased left ventricular ejection fraction. Most underwent median sternotomy for implantable cardioverter defibrillator implantation. The incidence of perioperative mortality was found to be 2.7%. New-onset atrial fibrillation or flutter occurred in 17.3% of the patients during the postoperative period and aggravation of ventricular tachyarrhythmias in 19.1%. The ICD system became infected in 2.7% of the patients and the mediastinal incision site infected in 2.4%. Pneumonia developed in 4.5%. Other complications included significant blood loss, ICD pocket hematomas, and lead dislodgement. There is an appreciable incidence of morbidity and mortality associated with ICD implantation.

Longitudinal study of magnetic resonance imaging and standard X-rays to assess disease progression in osteoarthritis.

OBJECTIVE: To investigate, over 1-year, the relationship between X-ray and magnetic resonance imaging (MRI) findings in patients with knee osteoarthritis (OA). METHODS: Sixty-two osteoarthritic patients (46 women) were followed for 1 year. At baseline and after 1 year, volume and thickness of cartilage of the medial tibia, the lateral tibia and the femur were assessed by MRI. A global score from the multi-feature whole-organ MRI scoring system (WORMS) was calculated for each patient at baseline and after 1 year. This score combined individual scores for articular cartilage, osteophytes, bone marrow abnormality, subchondral cysts and bone attrition in 14 locations. It also incorporated scores for the medial and lateral menisci, anterior and posterior cruciate ligaments, medial and lateral collateral ligaments and synovial distension. Lateral and medial femoro-tibial joint space width (JSW) measurements, performed by digital image analysis, were assessed from fixed-flexion, postero-anterior knee radiographs. RESULTS: One-year changes in medial femoro-tibial JSW reach 6.7 (20.5) % and changes in medial cartilage volume and thickness reach 0.4 (16.7) % and 2.1 (11.3) %, respectively. Medial femoro-tibial joint space narrowing (JSN) after 1 year, assessed by radiography, was significantly correlated with a loss of medial tibial cartilage volume (r=0.25, P=0.046) and medial tibial cartilage thickness (r=0.28, P=0.025), over the same period. We found also a significant correlation between the progression of the WORMS and radiographic medial JSN over 1 year (r=-0.35, P=0.006). All these results remained statistically significant after adjusting for age, sex and body mass index. CONCLUSION: This study shows a moderate but significant association between changes in JSW and changes in cartilage volume or thickness in knee joint of osteoarthritic patients.

Osteoarthritis, magnetic resonance imaging, and biochemical markers: a one year prospective study.

OBJECTIVE: To investigate the relation between biochemical markers of bone, cartilage, and synovial remodelling and the structural progression of knee osteoarthritis. METHODS: 62 patients of both sexes with knee osteoarthritis were followed prospectively for one year. From magnetic resonance imaging (MRI), done at baseline and after one year, the volume and thickness of cartilage of the femur, the medial tibia, and the lateral tibia were assessed. A whole organ magnetic resonance imaging score (WORMS) of the knee was calculated for each patient at baseline and at the one year visits. This score consists in a validated, semiquantitative scoring system for whole organ assessment of the knee in osteoarthritis using MRI. Biochemical markers (serum hyaluronic acid, osteocalcin, cartilage glycoprotein 39 (YKL-40), cartilage oligomeric matrix protein (COMP), and C-telopeptide of type I collagen (CTX-I), and urine C-telopeptide of type II collagen (CTX-II)) were measured at baseline and after three months. RESULTS: Baseline markers were not correlated with one year changes observed in cartilage volume and thickness. However, an increase in CTX-II after three months was significantly correlated with a one year decrease in mean thickness of medial tibial and lateral tibial cartilage. Patients in the highest quartile of three month changes in CTX-II experienced a mean loss of 0.07 (0.08) mm of their medial thickness, compared with a mean increase of 0.05 (0.19) mm for patients in the lowest quartile (p = 0.04) Multiple regression analysis showed that high baseline levels of hyaluronic acid are predictive of a worsening in WORMS (p = 0.004). CONCLUSIONS: These results suggest that a single measurement of serum hyaluronic acid or short term changes in urine CTX-II could identify patients at greatest risk of progression of osteoarthritis.

Bone marrow abnormalities on magnetic resonance imaging are associated with type II collagen degradation in knee osteoarthritis: a three-month longitudinal study.

OBJECTIVE: Using radiography to assess the efficacy of a disease-modifying osteoarthritis (OA) drug on joint structure is challenging. Subchondral bone marrow abnormalities determined by magnetic resonance imaging (MRI) and urinary excretion of C-terminal crosslinking telopeptide of type II collagen (CTX-II) have recently been shown to be predictors of radiographic progression in patients with knee OA, suggesting that these may represent valuable biomarkers with increased sensitivity compared with findings on radiography. The aims of this investigation were to analyze, in patients with knee OA, whether the values associated with these 2 OA biomarkers can change within 3 months, and to investigate the relationships between bone marrow abnormalities and CTX-II. METHODS: Knee MRI scans were obtained in 377 patients with painful knee OA (76% women, mean age 63 years, mean disease duration 6.6 years) at both baseline and 3 months. The femoral and tibial condyles and the patella were divided into 8 sites for the scoring of bone marrow abnormalities. A bone marrow abnormality was defined as an area of increased signal on T2-weighted images of the subchondral bone. All scans were reviewed centrally and scored by a single trained radiologist using a validated 4-point scoring method. Fasting urine and serum samples were also collected from all patients at baseline, month 1, month 2, and month 3, in order to measure the levels of urinary CTX-II and serum CTX-I, a biochemical marker of bone resorption. RESULTS: At baseline, 82% of patients had MRI evidence of bone marrow abnormalities. Bone marrow abnormality scores correlated significantly with CTX-II levels (P < 0.0001). Within 3 months, the bone marrow abnormality score decreased in 37 patients (9.8%), increased in 71 patients (18.8%), and did not change in the majority of patients (71.4%). Patients with baseline urinary CTX-II levels in the highest tertile had a relative risk of 2.4 (95% confidence interval 1.1-5.0) of worsening bone marrow abnormalities at 3 months compared with patients with levels in the lowest tertile, after adjustment for age, sex, and body mass index. In patients who showed a decrease in the bone marrow abnormality score at 3 months, urinary CTX-II levels decreased significantly (mean -75 ng/mmole creatinine), whereas levels increased (mean +23 ng/mmole creatinine) in patients showing an increase in the bone marrow abnormality score (P = 0.01 between the 2 groups). No significant association between bone marrow abnormalities and serum CTX-I was observed. CONCLUSION: In patients with painful knee OA, bone marrow abnormalities on MRI can change within only 3 months in approximately 30% of patients. Reduction in the extent of bone marrow abnormalities is associated with a decrease in cartilage degradation.

Orthostatic intolerance and syncope associated with Chiari type I malformation.

The Chiari type I malformation (CM1) is characterized by herniation of cerebellar tonsils to at least 3-5 mm below the plane of foramen magnum and can present with a wide variety of clinical symptoms, frequently including occipital headaches, secondary to bulbar and/or medullary distress. Rarely, syncopal episodes have also been described and attributed to either compression of the midbrain ascending reticular system, or vascular compromise (vertebrobasilar artery compression, hypotension). We report the first case of a CM1 patient with frequently recurring syncope due to postural orthostatic tachycardia syndrome (POTS), a form of orthostatic intolerance, whose symptoms resolved completely after surgical intervention. It is important to stress that it is not clear whether the described association of POTS and CM1 in our patient is a fortuitous finding in an isolated case or a reflection of a more systematic association between the two pathologies.

Cellular electrophysiology and beta-adrenergic-blocking activity of dilevalol, the R,R-isomer of labetalol, on isolated canine cardiac tissues.

Dilevalol is a beta-adrenergic receptor-blocking drug derived from labetalol. Many beta blockers exert local anesthetic effects or alter repolarization in cardiac tissue. Because the cellular electrophysiologic effects of dilevalol have not been studied, we investigated the actions of dilevalol on canine cardiac tissues using standard microelectrode techniques. We also tested the beta-blocking actions of dilevalol in isolated Purkinje fibers. This was done by measuring the inhibition of the positive chronotropic response to 10(-6) M isoproterenol before and after treatment with the drug. Dilevalol at 10(-9) M produced slight beta blockade, whereas 10(-6) M produced maximal (approximately 90%) effects. In normal Purkinje fibers, dilevalol less than or equal to 10(-6) M did not change the dV/dtmax or action potential duration (APD). Dilevalol at 10(-5) M produced rate-dependent decreases of dV/dtmax, and decreased the plateau amplitude while prolonging total APD of the Purkinje fibers. In ventricular muscle cells, dilevalol greater than or equal to 10(-8) M increases APD, whereas less than or equal to 10(-5) M does not decrease dV/dtmax. Dilevalol less than or equal to 10(-6) M does not decrease automaticity in Purkinje fibers at either the high or the low level of membrane potential. In summary, dilevalol produces significant beta blockade in normal cardiac tissues. The dose-response curve for this action is comparable to that of propranolol. Dilevalol also prolongs APD in ventricular muscle cells. Dilevalol may reduce arrhythmias through either class II or class III effects.

Effects of pinacidil, verapamil, and heart rate on afterdepolarizations in the guinea-pig heart in vivo.

Recently, ionic current simulation in the Luo-Rudy model has elucidated putative mechanisms of afterdepolarizations under various experimental conditions. The present study was aimed at gaining insight into the differential mechanism of different types of afterdepolarizations in the guinea-pig heart in vivo. The effects of pharmacological and heart rate perturbations on early (EADs) and delayed (DADs) afterdepolarizations, induced by either digoxin, CsCl, or BayK 8644 were studied, using mid-myocardial left ventricular monophasic action potential (MAP) recordings. Digoxin insignificantly shortened sinus cycle length (SCL) and CsCl and BayK 8644 differentially prolonged SCL and MAP duration. Digoxin induced phase 3-EADs and DADs and CsCl or BayK 8644 induced phase 2- and phase 3-EADs. Pinacidil shortened MAP duration, suppressed almost all the phase 2-EADs and some of the phase 3-EADs, but not the DADs. In a few cases, DADs were manifested following the abolishment of phase 2-EADs by pinacidil, but this phenomenon did not occur in the presence of hexamethonium. Verapamil prolonged SCL, did not significantly affect phase 2-EADs, but suppressed almost all of the DADs, including those which appeared after pinacidil, and all but one of the phase 3-EADs. The effects of pinacidil and verapamil were independent of the mode of afterdepolarization induction. A pacing-induced heart rate increase, which shortened MAP duration, and vagal stimulation, which prolonged MAP duration, attenuated and enhanced phase 2-EADs, respectively. The amplitude of phase 3-EADs was inversely related to the heart rate. These data, taken together, are consistent with those obtained previously by others in a computer model and recent observations on CsCl-induced EADs in the guinea-pig Purkinje fibers in vitro which have indicated that the mechanism of phase 2-EADs is different from that of DADs and that late phase 3-EADs generated under conditions of Ca2+ overload and DADs share similar properties.

Automatic and triggered impulse initiation in canine subepicardial ventricular muscle cells from border zones of 24-hour transmural infarcts. New mechanisms for malignant cardiac arrhythmias?

With standard microelectrode techniques, electrical activity of cells in the epicardial border zones of infarcts in the canine heart were studied. Either automaticity or triggered activity (or both) occurred in each of the 12 preparations studied from 24-hour infarcts. One 24-hour preparation had continuous activity indistinguishable from low-potential (abnormal) automaticity. This automaticity was not effected by flecainide 1-5 mg/l. Two other 24-hour subepicardial muscle preparations also were automatic. However, nine preparations from the subepicardium were not automatic during superfusion with standard Tyrode's solution. Delayed afterdepolarizations (DADs) and triggered activity could be induced in all of these preparations by treatment with catecholamines. The amplitude of these DADs was directly related to the stimulus rate of the train of impulses used to elicit them, and their coupling interval was inversely related to this rate of stimulation. Triggered activity occurred from maximal diastolic potentials of -58 to -88 mV in the 24-hour infarct zone preparations. In seven preparations from 72-96-hour infarct zones, the epicardial muscle cells did not show triggered activity after treatment with catecholamines. In one preparation from a 72-hour infarct, however, 3-5-mV DADs occurred. No DADs or triggered impulses occurred in subepicardial muscle from normal, noninfarcted hearts. Thus, triggered impulses and low-potential automaticity could contribute to arrhythmias occurring in the canine heart 24 hours after coronary ligation.

Rhabdomyolysis associated with naltrexone.

OBJECTIVE: To report a possible association between naltrexone therapy and the development of rhabdomyolysis in one patient. CASE SUMMARY: A 28-year-old white man in good physical health was started on naltrexone 50 mg/d for inpatient treatment of alcohol dependence and depression. A routine serum chemistry panel obtained on day 9 of naltrexone therapy showed marked new elevations in creatine kinase and aspartate aminotransferase. The patient remained asymptomatic and did not develop renal insufficiency. The serum enzyme concentrations returned to normal within eight days of naltrexone discontinuation. DISCUSSION: Rhabdomyolysis has not been previously reported to occur in patients during treatment with naltrexone. Alcoholism may result in a reversible acute muscle syndrome, but our patient did not fit the appropriate clinical profile for such a syndrome. Additionally, the other prescribed medications could not be implicated as possible causative agents. CONCLUSIONS: This case report illustrates a possible association between naltrexone therapy and rhabdomyolysis.

New radiographic-based surrogate outcome measures for osteoarthritis of the knee.

OBJECTIVE: Minimum joint space width (mJSW) between the femoral condyle and tibial plateau is currently the principal radiographic outcome measure for knee osteoarthritis (OA). While mJSW measurement has been proven effective, there is a need for quantitative measures with greater sensitivity to OA so studies of disease modifying trials can be performed more quickly and with fewer subjects. Also, mJSW is a single outcome measure that does not reflect all disease changes. Here we present a study of new radiograph-based outcome measures to quantify OA progression. DESIGN: Our goal is made possible by a software algorithm that delineates both the edge of the tibial plateau and the femoral condyle on digitized knee radiographs. We also developed a new coordinate system based on anatomical landmarks to facilitate measurement of the outcome measures. We studied measurements of joint space width (JSW) and average JSW at fixed locations along the joint interface. The outcome measures were tested using duplicate acquisitions made from 16 OA and 18 normal knees. Reproducibility was quantified by the root-mean square standard deviation and the coefficient of variation. RESULTS: We found that the reproducibility for all outcome measures was better than or similar to that for mJSW. Despite a slightly higher reproducibility error for some new outcome measures compared to mJSW, they are potentially valuable since they reflect independent disease changes. CONCLUSION: We have demonstrated new reproducible radiographic outcome measures to quantify OA progression with the potential to be an improvement over standard minimum joint space width.