Osteophytes and progression of knee osteoarthritis.

OBJECTIVES: Osteophytes are thought to stabilize an osteoarthritic joint, thereby preventing structural progression. Meagre longitudinal data suggest, however, that they are associated with an increased risk of structural progression. Our objective was to evaluate the effect of osteophyte size on radiographic progression in osteoarthritis (OA). METHODS: Using data from a natural history study of persons with symptomatic knee OA, we obtained fluoroscopically positioned postero-anterior (PA) radiographs at baseline, 15 and 30 months. Using an atlas, osteophyte size was scored on a scale of 0-3 at each of four sites on the PA film and, for each knee, both compartment-specific (i.e. medial; lateral) and overall osteophyte scores were computed. Progression was defined as an increase over follow-up in medial or lateral joint space narrowing, based on a semiquantitative grading. Mechanical alignment was assessed using long limb films at the 15 month examination. Logistic regression was used to evaluate the relation of osteophyte size with progression, adjusting for age, gender and body mass index, and with and without adjustment for alignment. RESULTS: Of 270 subjects who had 470 eligible knees with follow-up, 104 (22%) knees showed progression. Overall, osteophyte score modestly increased the risk of progression [odds ratio (OR) per S.D. increase of osteophyte score=1.4 (95% CI 1.1, 1.8, P=0.02)], but this effect weakened and became non-significant after adjustment for limb alignment (OR=1.3). Compartment osteophyte score was strongly associated with malalignment to the side of the osteophyte (e.g. medial osteophyte and varus). Compartment-specific osteophyte score markedly increased the risk of ipsilateral progression (e.g. medial osteophytes --> medial progression) [OR per S.D.=1.9 (95% CI 1.5, 2.5, P<0.001)] and decreased the risk of contralateral progression [OR per S.D.= 0.6 (95% CI 0.5, 0.8, P=0.002)], but these associations diminished when we adjusted for limb alignment (OR=1.5 and 0.7 respectively). CONCLUSIONS: Large osteophytes do not affect the risk of structural progression. They are strongly associated with malalignment to the side of the osteophyte, and any relation they have with progression is partly explained by the association of malalignment with progression.

The association of bone marrow lesions with pain in knee osteoarthritis.

BACKGROUND: The cause of pain in osteoarthritis is unknown. Bone has pain fibers, and marrow lesions, which are thought to represent edema, have been noted in osteoarthritis. OBJECTIVE: To determine whether bone marrow lesions on magnetic resonance imaging (MRI) are associated with pain in knee osteoarthritis. DESIGN: Cross-sectional observational study. SETTING: Veterans Affairs Medical Center. PATIENTS: 401 persons (mean age, 66.8 years) with knee osteoarthritis on radiography who were drawn from clinics in the Veterans Administration health care system and from the community. Of these persons, 351 had knee pain and 50 had no knee pain. MEASUREMENTS: Knee radiography and MRI of one knee were performed in all participants. Those with knee pain quantified the severity of their pain. On MRI, coronal T(2)-weighted fat-saturated images were used to score the size of bone marrow lesions, and each knee was characterized as having any lesion or any large lesion. The prevalence of lesions and large lesions in persons with and without knee pain was compared; in participants with knee pain, the presence of lesions was correlated with severity of pain. RESULTS: Bone marrow lesions were found in 272 of 351 (77.5%) persons with painful knees compared with 15 of 50 (30%) persons with no knee pain (P < 0.001). Large lesions were present almost exclusively in persons with knee pain (35.9% vs. 2%; P < 0.001). After adjustment for severity of radiographic disease, effusion, age, and sex, lesions and large lesions remained associated with the occurrence of knee pain. Among persons with knee pain, bone marrow lesions were not associated with pain severity. CONCLUSIONS: Bone marrow lesions on MRI are strongly associated with the presence of pain in knee osteoarthritis.

Detecting radiographic knee osteoarthritis: what combination of views is optimal?

OBJECTIVE: The failure to image the patellofemoral joint or the posterior knee compartment when evaluating persons for knee osteoarthritis may result in missed cases. While the skyline view has been recommended due to more reproducible assessment of the patellofemoral joint space, the lateral view may be easier to acquire and provides different information. We evaluated the sensitivity of different combinations of X-ray views (anteroposterior and lateral; anteroposterior and skyline; all three views) in 377 persons with knee symptoms who had all three views available and had a definite osteophyte on at least one view. RESULTS: Of the different views, skylines had to be excluded most often because the image of the patellofemoral joint was technically unsatisfactory. In the remaining knees, adding either a lateral or a skyline view to an anteroposterior view yielded roughly equal and high sensitivity (94-97%) when compared with the gold standard of a positive X-ray on any of the three views. CONCLUSION: As long as at least an anteroposterior view and one image of the patellofemoral joint is obtained (either skyline or lateral), few cases with radiographic disease will be missed. For clinical or epidemiological studies the lateral view may be easier to acquire with high quality than the skyline view.

An automated PACS workstation interface: a timesaving enhancement.

OBJECTIVE: Interface design is a key element in the efficient use of a picture archiving and communication system (PACS) workstation. In many cases, multiple mouse clicks or keyboard commands are required to open and close a case, to mark it as complete, and to retrieve and allocate screen positions to the next case. We evaluated the work flow effect of software designed for automated image display in which all of these operations are consolidated in a single mouse click. CONCLUSION: Automated image display increases efficiency in image interpretation and remedies the normally cluttered presentation environment. At our institution, acceptance of automated image display has been overwhelmingly positive. In fact, automated image display has improved radiologist productivity.

DICOM modality worklist: an essential component in a PACS environment.

The development and acceptance of the digital communication in medicine (DICOM) standard has become a basic requirement for the implementation of electronic imaging in radiology. DICOM is now evolving to provide a standard for electronic communication between radiology and other parts of the hospital enterprise. In a completely integrated filmless radiology department, there are 3 core computer systems, the picture archiving and communication system (PACS), the hospital or radiology information system (HIS, RIS), and the acquisition modality. Ideally, each would have bidirectional communication with the other 2 systems. At a minimum, a PACS must be able to receive and acknowledge receipt of image and demographic data from the modalities. Similarly, the modalities must be able to send images and demographic data to the PACS. Now that basic DICOM communication protocols for query or retrieval, storage, and print classes have become established through both conformance statements and intervendor testing, there has been an increase in interest in enhancing the functionality of communication between the 3 computers. Historically, demographic data passed to the PACS have been generated manually at the modality despite the existence of the same data on the HIS or RIS. In more current sophisticated implementations, acquisition modalities are able to receive patient and study-related data from the HIS or RIS. DICOM Modality Worklist is the missing electronic link that transfers this critical information between the acquisition modalities and the HIS or RIS. This report describes the concepts, issues, and impact of DICOM Modality Worklist implementation in a PACS environment.

Meniscal subluxation: association with osteoarthritis and joint space narrowing.

OBJECTIVE: Since complete meniscectomy leads to knee OA, we investigated the potential links among meniscal subluxation, joint space narrowing and symptomatic OA. MATERIALS AND METHODS: 233 cases with symptomatic knee OA and 58 asymptomatic controls underwent radiography and MR imaging of the knee. Joint space narrowing was measured on weight-bearing PA fluoroscopy-positioned radiographs. The amount of medial or lateral meniscal subluxation was measured on coronal MR images. The prevalence and severity of meniscal subluxation was compared in cases and controls. We evaluated the correlation of the degree of meniscal subluxation with joint space narrowing, Kellgren and Lawrence grade, and two major risk factors for the development of OA, age and weight. RESULTS: Cases had more medial and lateral subluxation than controls. Mean medial meniscal subluxation was 5.1 mm in cases and 2.8 mm in controls (P=0.001). Modest degrees of meniscal subluxation were common in both cases and controls: 81% of cases and 64% of controls had >/=3 mm of subluxation; age and gender adjusted (P=0.006). Severe degrees of subluxation were almost unique to OA cases (e.g. prevalence of >/=7 mm, 35% cases vs. 7% controls, P< 0.001). Among controls, severe degrees of subluxation were present only in those with radiographic joint space narrowing (defined as >/=grade 1 narrowing on a 0-3 scale). In cases, there was a strong correlation between the degree of medial meniscal subluxation and the severity of medial joint space narrowing (r=0.56, P=0.0001). Similar results were present in the lateral compartment. Meniscal subluxation did not correlate with age or weight. CONCLUSION: Meniscal subluxation is highly associated with symptomatic knee OA. In subjects with osteoarthritis, increasing meniscal subluxation on MR correlates with the severity of joint space narrowing.

Multicenter trial of gadoteridol, a nonionic gadolinium chelate, in patients with suspected head and neck pathology.

PURPOSE: To evaluate the safety and efficacy of gadoteridol as an MR contrast agent in patients with suspected head and neck pathology. METHODS: One hundred thirty-three adult patients were studied with MR at 12 clinical trial sites before and after the intravenous administration of 0.10 mmol/kg gadoteridol. After enrollment, patients underwent a complete physical examination. Patient monitoring included vital signs, laboratory tests, and recording of the incidence and duration of adverse events. To evaluate efficacy, postcontrast T1-weighted images were compared with precontrast T1- and T2-weighted images. Investigators having clinical information evaluated 129 studies for efficacy; two readers blinded to clinical information subsequently evaluated 122 studies using the same criteria as the investigators. RESULTS: Eight patients (6.0%) experienced mild adverse events possibly or probably related to contrast administration, all of which resolved without treatment. Two clinically significant laboratory abnormalities considered related or possibly related to the administration of gadoteridol were reported in two patients. Enhancement of pathology was seen in 82.9% of cases evaluated by investigators at the study site and in 78.7% of cases subsequently evaluated by the blinded readers. Postcontrast images were judged by investigators to provide additional diagnostic information over precontrast images in 68.9% of studies. The additional diagnostic information available on postcontrast studies most often consisted of improved visualization of pathology and better definition of lesion borders. The use of this information might have contributed to a change in patient diagnosis in 18.6% of the cases evaluated by the investigators and in 16.4% of the cases reviewed by the blinded readers. CONCLUSIONS: Preliminary results show gadoteridol to be a safe and efficacious contrast agent for enhanced MR study of extracranial and extraspinal head and neck pathology.

The coronary collateral circulation in normal goats.

This study was undertaken to evaluate the coronary collateral circulation of the goat. Year old, castrated male goats were anesthetized with sodium pentobarbital. A branch of the left circumflex coronary artery was dissected and a snare placed around it. Regional myocardial blood flow was measured by injecting colored microspheres into the left atrium before and during 3 hr of occlusion of this coronary artery. The Area At Risk for infarction, as defined by a left atrial injection of Brilliant Green dye, was divided into a central Ischemic zone and a peripheral Ischemic Border zone. The degree of overlap in the blood flow distributions between the risk and the nonrisk areas was quantitatively assessed by injecting microspheres directly into the artery to the Area At Risk. Baseline blood flow to the normally perfused goat myocardium was 1.13 +/- 0.18 ml/min/g (mean +/- SE). Following occlusion, the flow to the Ischemic zone was 0.07 +/- 0.03 ml/min/g and to the Ischemic Border zone was 0.31 +/- 0.18 ml/min/g. Flow to either zone did not increase during the 3-hr observation period. Overlap at the perimeter of the risk and nonrisk areas was approximately 22%. We conclude that flow to the Ischemic zone is low because the goat has few native collateral blood vessels, and that flow to the Ischemic Border zone is significantly affected by overlap with normal myocardium.

Long-term neurostimulation of skeletal muscle: its potential for a tether-free biologic cardiac assist device.

Skeletal muscle has a tremendous capacity to adapt. This adaptive phenomenon is seen perhaps to the greatest extent when skeletal muscle is subjected to chronic low frequency stimulation via the motor nerve. There is a decrease in glycolytic enzymes and an increase in oxidative enzymes, as well as a change in the contractile proteins and an increase in the mitochondrial volume fraction of the muscle fiber. These adaptive changes result in a muscle that is considerably more fatigue-resistant. Specifically herein, we report on a pneumatic aortic counterpulsator device powered by skeletal muscle. These muscle pumps functioned continuously and pumped blood effectively in tether-free animals for several weeks.

Gallium-67 breast uptake in a patient with hypothalamic granuloma (sarcoid).

An unusual case is presented of bilateral breast uptake of [67Ga]citrate in a patient with a hypothalamic granuloma in the absence of galactorrhea is presented. A possible mechanism for this incidental finding is elevated prolactin levels, as other causes of gallium breast uptake such as drug therapy, and intrinsic breast disease, were not present.

Canine diaphragm muscle after 1 yr of continuous electrical stimulation: its potential as a myocardial substitute.

Skeletal muscle has been rendered fatigue resistant by chronic stimulation and therefore has potential as an active substitute for damaged myocardium. It is therefore important to know whether stimulation produces any deleterious effects in the long term. Hemidiaphragm muscles of four dogs were examined after chronic stimulation for 1 yr at either 2 or 4 Hz. The stimulated hemidiaphragms appeared normal on gross inspection and were still contracting vigorously. By histochemical and immunohistochemical criteria, they had acquired a uniformly type I character, in contrast to the mixed fiber type composition of the unstimulated hemidiaphragms. This transformation was also reflected in their complement of myosin isozymes. There was some enzymatic evidence of an associated shift towards aerobic pathways of energy generation. Histological examination revealed no evidence of degenerative changes. Trends, observed in the shorter term (6-8 wk), toward a decrease in fiber area and an increase in connective tissue showed no further progression at 1 yr. Thus hemidiaphragm muscle stimulated at frequencies at or above the normal heart rate does not appear to undergo adverse long-term changes that would constrain its use in a myocardial assist role.

Pericardial fluid distribution: CT analysis.

Ultrasound and computed tomographic (CT) descriptions of pericardial effusion commonly indicate that fluid accumulates posteriorly within the pericardial sac before filling other areas. However, in a retrospective study of 68 cases of pericardial effusion identified on chest CT, most of the effusions were noted to be located solely or predominantly anterior to the right ventricle. Anatomic features of the pericardium and its fibrous attachments, and the physical principle of buoyancy account for this observation.

Esophageal invasion by lung cancer: CT diagnosis.

Esophageal wall invasion by primary lung carcinoma is an uncommon occurrence. When CT demonstrates a large primary parenchymal lung lesion that appears to cross the midline in the posterior mediastinum, dilute oral barium should be given during the CT examination to demonstrate the location of the esophagus. An esophagus involved by lung carcinoma may show contralateral displacement or partial obstruction. Furthermore, a malignant fistula between esophagus and trachea or lung may also be discovered.

An assessment of the role of scan speed in perceived image quality of body computed tomography.

Forty-three chest (noncardiac) and 75 abdominal computed tomographic (CT) examinations were studied by obtaining four sections of a pertinent area using 2.25-, 4.5-, 9-, and 18-second scan speeds. Chest scans obtained with the three faster speeds were perceived to be qualitatively similar to one another but were rated better than the 18-second sections. While these qualitative differences were statistically significant, most were relatively unimportant clinically. Analysis of the abdominal sections showed significant qualitative improvement with each successively faster scan speed. The only sections rated unreadable and/or showing large numbers of motion artifacts were abdominal studies, primarily 18-second studies. A statistically significant loss of diagnostic information was noted with 18-second scans, especially in the upper abdomen.

Further observations on the medical efficacy of computed tomography of the chest and abdomen.

A review of 262 consecutive 2-second CT scans (101 thoracic and 161 abdominal) revealed that 36% contributed information critical to diagnosis, prognosis or therapy. As a result of CT-derived data, major surgery was cancelled in 16 cases and planned surgery modified in 11. Similarly, CT contributed to treatment planning in 20 instances. Forty-four per cent of the studies produced new information but did not have definite clinical impact. Marked improvement in efficacy is noted when these data are compared to our previous study of 2 1/2-minute CT examinations. The improvement is ascribed to better imaging (faster scan speed), improved diagnostic skill, better patient selection, and improved credibility of CT-derived data.

Ultrastructural aspects of the transformation of muscle fibre type by long term stimulation: changes in Z discs and mitochondria.

The criteria which serve to distinguish the slow from the fast type of mammalian skeletal muscle include differences at the ultrastructural level, in particular differences in Z disc morphology and mitochondrial content. If a fast muscle is subjected to sustained low frequency impulse activity similar to that normally received by a slow muscle, its physiological and biochemical properties become indistinguishable from those of a slow muscle. In the present study we have examined the fine structure of fast muscles stimulated in this way. The thickness of Z discs was significantly greater than that of control fast muscles and indistinguishable from that of slow muscles. Mitochondrial profiles, seen only infrequently in control fast muscles, were abundant in their stimulated counterparts. The regulatory influence of impulse activity on the differentiation of skeletal muscle thus extends to some of its most characteristic ultrastructural features.