Magnetic resonance arthrography assessment of the superior labrum using the BLC system: age-related changes mimicking SLAP-2 lesions.

OBJECTIVE: The purpose of the study was to describe the variation of the superior labrum with increasing age by assessing magnetic resonance (MR) arthrograms. METHODS: Inclusion criteria were used to include only the MR arthrograms of patients devoid of clinical labral pathology. Two hundred thiry-six MR arthrograms were blindly assessed for biceps-labral complex (BLC) type 1-3 and sublabral recess size by a musculoskeletal radiologist. We have chosen the BLC system, which defines normal superior labral variants, since it is established in the literature and is used by reporting musculoskeletal (MSK) radiologists. RESULTS: The MR arthrograms demonstrated that the majority of patients <40 years old were BLC type 1 and showed a steady increase in BLC types 2 and 3 with increasing age. Assessments demonstrated significantly greater (p < 0.01) mean BLC types (1.62 vs 1.29) and recess size (1.35 vs 0.66 mm) in those over 40 compared with those less than 40 years of age. Furthermore, significant differences (p < 0.05) were noted between mean BLC assessments between different decades of age. CONCLUSIONS: There appears to be a physiologic deepening of the superior labrum sulcus with age, which becomes significant after the age of 40. These findings can contribute to whether the superior labrum is considered abnormal when assessed radiographically. The differentiation of normal age-related changes in the shoulder, from those of a type 2 SLAP tear can reduce the rates of unnecessary SLAP-2 repairs. This is the first reported series to use the BLC system; we believe it provides a common nomenclature to allow clear communication between specialists.

Magnetic resonance imaging tendon integrity assessment after arthroscopic partial-thickness rotator cuff repair.

PURPOSE: Our goal was to assess the integrity of the repaired rotator cuff in patients with partial-thickness rotator cuff tears who underwent a technique of tear completion followed by surgical repair, using post-repair magnetic resonance imaging (MRI) at a minimum of 2 years' follow-up. METHODS: An all-arthroscopic surgical technique was used for these marked partial-thickness tears, by use of double-loaded footprint anchors and/or lateral sutures or anchors as appropriate for tissue quality. A total of 22 patients who had completion of the tear followed by repair were reimaged with 2-sequence noncontrast MRI to determine the integrity of the rotator cuff repair at a minimum of 2 years postoperatively. RESULTS: Of the 22 patients, 18 (82%) had no evidence of a full-thickness or near full-thickness defect on follow-up MRI. The presence of a defect on follow-up MRI (18%) did not correlate with clinical results. Younger patients showed a trend toward maintaining better integrity. CONCLUSIONS: In 18 of 22 patients (82%) with partial-thickness rotator cuff tears treated with tear completion followed by surgical repair, there was no evidence of a full-thickness or near full-thickness defect on follow-up MRI at a minimum of 2 years. The patient's age may be an important factor in tendon healing. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Reliability of non-imaging-guided glenohumeral joint injection through rotator interval approach in patients undergoing diagnostic MR arthrography.

OBJECTIVE: The purpose of our study is to review the accuracy of our method of non-imaging-guided anterior glenohumeral gadolinium contrast injection targeting the rotator interval in 100 consecutive patients. MATERIALS AND METHODS: One hundred consecutive community-referred patients at our MRI facility underwent non-imaging-guided glenohumeral contrast injection targeting the rotator interval, with no patients excluded on the basis of expected diagnosis. The studies were then retrospectively reviewed for accuracy of injection based on patient factors and diagnosis. RESULTS: This method was 99% accurate in our study, regardless of diagnosis. CONCLUSION: The relative ease, efficiency, reproducibility, and accuracy of this method of non-imaging-guided anterior glenohumeral injection make it the method of choice at our institution, and we believe this technique merits consideration for more widespread utilization.

Introduction: the fundamental constants of physics, precision measurements and the base units of the SI.

This is a short introductory note to the texts of lectures presented at a Royal Society Discussion meeting held on 14-15 February 2005 and now published in this issue of Philosophical Transactions A. It contains a brief resumé of the papers in the order they were presented at the meeting. This issue contains the texts of all of the presentations except those of Christophe Salomon, on cold atom clocks and tests of fundamental theory, and Francis Everitt, on Gravity Probe B, which were, unfortunately, not available.

From pedigree cats to fluffy-bunnies.

We consider two distinct classes of quantum mechanical entanglement. The first "pedigree" class consists of delicate highly entangled states, which hold great potential for use in future quantum technologies. By focusing on Schrodinger cat states, we demonstrate not only the possibilities these states hold but also the difficulties they present. The second "fluffy-bunny" class is made up of robust states that arise naturally as a result of measurements and interactions between particles. This class of entanglement may be responsible for the classical-like world we see around us.

Bose-Einstein condensates and precision measurements.

An ongoing challenge in physics is to make increasingly accurate measurements of physical quantities. Bose-Einstein condensates in atomic gases are ideal candidates for use in precision measurement schemes since they are extremely cold and have laser-like coherence properties. In this paper, we review these two attributes and discuss how they could be exploited to improve the resolution in a range of different measurements.

Quantum encounters of the cold kind.

Since the introduction of laser-cooling techniques for neutral atoms in the early 1980s, the study of collisional interactions between atoms and molecules has been extended to the regime of ultracold temperatures. With nanokelvin temperatures now attainable, our ability to probe the interactions, both experimentally and theoretically, has also progressed. Understanding of the subtle and often highly quantum-mechanical effects that are manifest at such low energies has advanced to the point where new precision measurements are matched by highly accurate theoretical calculations. Low-energy phenomena such as Bose-Einstein condensation and the photoassociation of atoms into bound molecules are now accurately described with no free parameters.