Posterior horn medial meniscal root tear: the prequel.

OBJECTIVE: To determine whether subarticular marrow changes deep to the posterior horn medial meniscal root anchor might predict subsequent medial meniscal root tear. MATERIALS AND METHODS: Fifteen patients with MR-diagnosed posterior horn medial meniscal root (PHMMR) tear and a knee MRI antecedent to the tear were identified at three imaging centers over a 7-year period. The pre- and post-tear MR images were evaluated for marrow signal changes deep to the root anchor, meniscal root signal intensity, medial compartment articular cartilage thinning, and meniscal body extrusion. Images of 29 age- and gender-matched individuals with two MRIs of the same knee were reviewed as a control group. RESULTS: MRI in 11 of 15 (73%) cases with subsequent PHMMR tear demonstrated linear subcortical marrow edema deep to the meniscal root anchor on the antecedent MRI compared to only 1 of 29 (3%) non-tear controls (p < 0.0001). The abnormal signal resolved on post-tear MRI in all but two patients. Cyst-like changes deep to the PHMMR were present on initial MRI in three of 15 (23%) cases and three of 29 (10%) controls, persisting in all but one case on follow-up imaging. The PHMMR was gray on the initial MRI in seven of 15 (47%) of cases that developed tears compared to four of 29 (14%) controls (p < 0.0001). There was medial meniscal extrusion (MME) prior to tear in two of 15 (13%) patients and in ten of 15 (67%) patients after PHMMR failure. In the control group, MME was present in one (3%) and three (10%) of 29 subjects on the initial and follow-up MRIs, respectively. Articular cartilage loss was noted in two of 15 (15%) cases before tear and nine of 15 (69%) on follow-up imaging, as compared to one (3%) and four (14%) of 29 subjects in the control group. CONCLUSIONS: Subcortical marrow edema deep to the PHMMR may result from abnormal stresses and thus be a harbinger of meniscal root failure. This hypothesis is supported by resolution of these marrow signal changes after root tear. Following tear, extrusion of the meniscal body results in increased stress on the medial weight-bearing surfaces often leading to articular cartilage loss; we observed this sequence in six of our 15 patients with PHMMR tears.

Bucket handle tears of the medial meniscus: meniscal intrusion rather than meniscal extrusion.

OBJECTIVE: To determine the frequency of medial meniscal extrusion (MME) versus "medial meniscal intrusion" in the setting of bucket handle tears. Images were evaluated for previously reported risk factors for MME, including: medial meniscal root tear, radial tear, degenerative joint disease and joint effusion. METHODS: Forty-one consecutive cases of bucket handle tear of the medial meniscus were reviewed by consensus by two musculoskeletal radiologists. Imaging was performed using a 1.5 GE Signa MR unit. Patient age, gender, medial meniscal root integrity, MME, medial meniscal intrusion, degenerative joint disease, effusion and anterior cruciate ligament (ACL) tear were recorded. RESULTS: Thirteen females and 27 males (age 12-62 years, median=30 years) were affected; one had bucket handle tear of each knee. Effusion was small in 13, moderate in 9 and large in 18. Degenerative joint disease was mild in three, moderate in two and severe in one. 26 ACL tears included three partial and three chronic. Medial meniscal root tear was complete in one case and partial thickness in two. None of the 40 cases with an intact or partially torn medial meniscal root demonstrated MME. MME of 3.1 mm was seen in the only full-thickness medial meniscal root tear, along with chronic ACL tear, moderate degenerative joint disease and large effusion. Medial meniscal intrusion of the central bucket handle fragment into the intercondylar notch was present in all 41 cases. CONCLUSION: Given an intact medial meniscal root in the setting of a "pure" bucket handle tear, there is no MME.

Direct gamma-spectrometric measurement of the 226Ra 186.2keV line for detecting 238U/226Ra disequilibrium in determining the environmental dose rate for the luminescence dating of sediments.

In the age determination of sediments according to the luminescence method, it is important to know whether there was secular equilibrium in the Th and U decay series during accumulation of the environmental radiation dose in geological times. This can be investigated via gamma-ray spectrometry, whereby--in the (238)U series--(214)Pb and (214)Bi are considered as the indicators for (226)Ra-mobility, and (210)Pb as the indicator for (226)Rn-emanation. In the present work, the direct measurement of (226)Ra--which can give extra information on the interpretation of the radioactive equilibrium--is investigated as to its precision and accuracy. Since there is a serious spectral interference on its 186.2keV gamma-line (by (235)U at 185.7keV), various correction procedures were outlined and their performance was checked via the analysis of (certified) reference materials, leading to the recommendation of a "method of choice".

The role of meniscal root pathology and radial meniscal tear in medial meniscal extrusion.

OBJECTIVE: The purpose of our study was twofold: to better understand the relationship between medial meniscal extrusion (MME) and degenerative joint disease (DJD), and to determine whether a relationship exists between MME and medial meniscal root (MMR) pathology, radial tear and joint effusion. DESIGN AND PATIENTS: Two hundred and five consecutive MR imaging examinations of the knee were prospectively evaluated, regardless of indication, for the presence and degree of MME, medial compartment marginal osteophytes, medial compartment articular cartilage loss, joint effusion, medial meniscal tear and MMR pathology. MME >or=3 mm was considered abnormal. All studies were performed using a 1.5 T GE Signa MR unit with a quadrature knee coil. The standard protocol included oblique sagittal, coronal and axial imaging. RESULTS: We found a strong association ( P<0.0001) between >or=3 mm MME and medial joint line osteophytosis (77%), medial compartment articular cartilage loss (69%), MMR pathology (64%) and radial tear (58%) when compared with knees without these findings. Fifty-one percent of cases with a moderate/large joint effusion had <3 mm MME. We found that 20% (31/155) of patients with minimal or no evidence of DJD had >or=3 mm MME. Of this group, 62% (19/31) had either MMR pathology and/or radial tear, 13% (4/31) had joint effusion as their only abnormality and 6% (2/31) had a normal examination (other than the presence of MME). The remaining 19% consisted of three cases of different types of meniscal tear and three cases of small joint effusions but no other detectable pathology. CONCLUSION: MME >or=3 mm is strongly associated with DJD, MMR pathology and radial tear. A significant number of cases with no or minimal evidence of DJD (20%) had >or=3 mm MME, suggesting that MME precedes, rather than follows, the development of DJD. We also found that joint effusion was not strongly associated with >or=3 mm MME.

MRI features of confirmed "pre-slip" capital femoral epiphysis: a report of two cases.

We describe the morphologic and signal changes detected about the proximal femoral growth plate in two patients with hip pain preceding the progression to slipped capital femoral epiphysis using magnetic resonance imaging.

The plantar plate of the lesser metatarsophalangeal joints: potential for injury and role of MR imaging.

This article reviews the normal anatomy of the plantar plate and surrounding support structures at the lesser metatarsophalangeal joints, and demonstrates degenerative change and rupture using high resolution MR imaging of the forefoot. The etiology of plantar plate and collateral ligament degeneration and rupture, most commonly occurring at the second metatarsophalangeal joint, is discussed as it relates to chronic synovitis and instability. Both conservative and surgical treatment options are discussed.

Correlation of radiographic and arthroscopic findings with rotator cuff tears and degenerative joint disease.

The purpose of this study was to identify early signs of rotator cuff tear and glenohumeral articular cartilage degeneration by using conventional radiography. A non-weighted anteroposterior oblique and a weighted active abduction view were evaluated for superior humeral migration and matching degenerative changes at the inferolateral acromion and superior aspect of the greater tuberosity in 40 patients who underwent shoulder arthroscopy. Measurements of the glenohumeral distance were performed. Surgical reports were reviewed to determine rotator cuff and glenohumeral articular cartilage status. Matching degenerative changes correlate with complete rotator cuff tear (P =.04); superior migration does not. Severe glenohumeral cartilage loss correlates with narrowing of the superior joint space on the anteroposterior oblique radiograph (P =.02) and with narrowing of the mid joint space on the active abduction view (P =.05). Both glenohumeral articular cartilage degenerative change and rotator cuff injury, before formation of typical sequelae of chronic rotator cuff tear, can be detected with the use of conventional radiography.

Megalophallus as a sequela of priapism in sickle cell anemia: use of blood oxygen level-dependent magnetic resonance imaging.

Priapism is a common complication of sickle cell anemia. We report a little known sequela of priapism: painless megalophallus, with significant penile enlargement. The patient had had an intense episode of priapism 9 years previously and his penis remained enlarged. Blood oxygen level-dependent magnetic resonance imaging revealed enlarged, hypoxic corpora cavernosa. Megalophallus probably resulted from permanent loss of elasticity of the tunica albuginea due to severe engorgement during the episode of priapism. This sequela needs to be recognized by physicians because no intervention is necessary and sexual function seems to remain intact.

The diagnostic role of gadolinium enhanced MRI in distinguishing between acute medullary bone infarct and osteomyelitis.

The objective of the study was to evaluate the diagnostic utility of contrast enhanced magnetic resonance imaging (MRI) for distinguishing between acute medullary bone infarct and osteomyelitis. There were 11 patients (age 6-34 years) presented to our institution between December 1994 and February 1998 with a clinical differential diagnosis of acute bone infarct versus osteomyelitis and inconclusive radiographs were imaged using MRI. All but one received i.v. gadolinium. Nine of the patients had homozygous Sickle Cell disease (SCD) and two had Systemic Lupus Erythematosus (SLE), the latter requiring chronic methylprednisolone. Osteomyelitis was confirmed either by biopsy alone or by the combination of Gallium(67) scan in conjunction with positive blood cultures and clinical resolution following antibiotics. Infarcts without osteomyelitis were confirmed either by biopsy or resolution of symptoms without antibiotic therapy. All patients had at least six months clinical follow-up. The results found that seven of nine patients with SCD had acute infarct only. One patient with SCD had osteomyelitis only. Three patients (two SLE and one SCD) had both acute-on-chronic infarcts and superimposed osteomyelitis, one with an adjacent soft tissue abscess. Accurate distinction between infarct and osteomyelitis was impossible for one patient with SLE who did not receive contrast. All other cases were correctly diagnosed prospectively based on distinct patterns of MRI contrast enhancement. In all adult patients, acute infarcts demonstrated thin, linear rim enhancement on MRI while osteomyelitis revealed more geographic and irregular marrow enhancement. Two of four cases of osteomyelitis also demonstrated subtle cortical defects with abnormal signal traversing marrow and soft tissue. The single pediatric patient demonstrated elongated, serpiginous central medullary enhancement with periostitis. We concluded that the pattern of MR contrast enhancement may allow accurate distinction between acute infarct and osteomyelitis, or recognition of osteomyelitis superimposed on bone infarction.

Scintigraphic findings in peroneal tendonitis: a case report.

A case report of radionuclide bone scan findings in a patient with peroneus brevis tendonitis is presented. Peroneal tendonopathy is a common cause of lateral ankle pain. Although magnetic resonance imaging (MRI) findings have been described in the literature, we know of no other detailed report of three-phase bone scan findings, which we believe can provide an alternate means to diagnose this condition. The positive findings consist of a curvilinear band of increased activity that corresponded to the anatomic position of the peroneus brevis tendon and was detected only on the first two phases of the study.

Slipped capital femoral epiphysis: a physeal lesion diagnosed by MRI, with radiographic and CT correlation.

OBJECTIVE: To define and compare early lesions associated with slipped capital femoral epiphysis (SCFE) on magnetic resonance imaging (MRI), computed tomography (CT) and radiography. DESIGN AND PATIENTS: Thirteen patients with 15 symptomatic hips due to SCFE underwent radiography and MRI; CT was performed in 12 patients. SCFE was graded on radiographs, head/neck angles and qualitative changes were evaluated on CT, and morphologic/signal abnormalities were determined on MRI. RESULTS: Physeal widening, apparent on T1-weighted MRI, was evident in every case of SCFE, including one presumed "pre-slip." T2-weighted images demonstrated synovitis and marrow edema but obscured physeal abnormalities. CT head/neck angles ranged from 4-57 degrees for symptomatic to 0-14 degrees for asymptomatic hips. Physeal and metaphyseal changes were variably identified on both radiographs and CT in all cases of SCFE, but not in the pre-slip. CONCLUSION: MRI clearly delineates physeal changes of both pre-slip and SCFE, and demonstrates very early changes at a time when radiographs and CT may appear normal.

Longitudinal stress fractures of the tibia: diagnosis by magnetic resonance imaging.

OBJECTIVE: Previous works describe magnetic resonance (MR) imaging characteristics of stress fractures. Diagnosis of the atypical, longitudinal type of stress fracture has been reported using computed tomography (CT). This report focuses on MR imaging of longitudinal stress fractures of the tibia. MATERIALS AND METHODS: Six cases are presented in which a longitudinal linear abnormal marrow signal was detected in the middle and distal parts of the tibial shaft. Five patients were imaged using a 1.5 Tesla MR unit. Axial, sagittal and coronal T1 and T2-weighted or fat suppressed proton density fast spin echo images were obtained in all but one patient. One patient was imaged using a 0.5 Tesla MR unit with axial and coronal T1- and T2-weighted sequences. Initial conventional radiographs seen at clinical presentation were interpreted as normal in all cases. Two patients underwent radionuclide bone scan. and one patient was imaged with CT prior to MR imaging. RESULTS: In each instance, MR imaging demonstrated linear marrow signal abnormalities orientated along the long axis of the tibial shaft. Endosteal and periosteal callus was identified on axial images. In all cases, MR imaging clearly demonstrated a fracture extending through one cortex with abnormal signal in both the marrow cavity as well as adjacent soft tissues indicating edema. CONCLUSION: MR imaging was shown to be excellent for demonstration of fracture lines, callus, and marrow and soft tissue abnormalities seen in association with longitudinal stress fractures.

Insufficiency fracture of the talus: diagnosis with MR imaging.

PURPOSE: To describe the clinical setting and pattern of talar insufficiency stress fractures as diagnosed with magnetic resonance (MR) imaging. MATERIALS AND METHODS: The authors retrospectively reviewed the clinical history and MR images from four patients with five talar insufficiency fractures. All patients were women (age range, 30-70 years). Images were evaluated for the location and orientation of fractures and the presence of concomitant osseous and soft-tissue injury. RESULTS: Concomitant fractures were identified in two patients. Only two fractures were typical in location and orientation at the talar neck. Three fractures were atypical in location and orientation. One occurred horizontally in the talar body and two occurred in the posteromedial talus (one was oriented vertically and one horizontally). Two patients had associated concomitant stress fractures--one in the distal tibia and one in the calcaneus. CONCLUSION: The location and orientation of talar insufficiency fractures is more variable than previously recognized. Specific diagnoses and coexisting fractures can be determined with MR imaging.

Diagnosis of partial tears of the anterior cruciate ligament of the knee: value of MR imaging.

OBJECTIVE: The purpose of our study was to assess the ability of MR imaging to detect partial tears of the anterior cruciate ligament (ACL) as these injuries, if extensive enough, may result in ligamentous insufficiency or predispose to subsequent acquired knee instability. MATERIALS AND METHODS: A review of all arthroscopic reports from two institutions during the periods 1990-1992 and 1992-1993, respectively, revealed 13 patients with partial tears of the ACL. Thirteen cases each of intact and completely ruptured anterior cruciate ligaments on arthroscopy were randomly selected as controls from the same report review. Preoperative MR images for all cases selected were obtained. Criteria for diagnosis included the absence of findings of complete ACL tear in conjunction with abnormal intrasubstance signal, bowing of the ACL, or nonvisualization of the ACL on one MR imaging sequence with visualization of intact fibers on other sequences. Inter- and intraobserver agreement was assessed using the kappa statistic. RESULTS: The sensitivity of MR imaging for detecting partial ACL tears ranged from 0.40 to 0.75, and the specificity ranged from 0.62 to 0.89. Variability of both inter- and intraobserver interpretations was greater than 0.7 kappa in all but one combination, comparing the diagnostic consistency of each of three readers both with himself, using two readings on separate days, and with each separate interpretation by the other two radiologists. CONCLUSION: Our results show that MR evaluation of partial ACL tears is not sufficiently sensitive to establish the diagnosis without arthroscopy. This study was limited, however, by its small size and by the heterogeneity of the MR imaging technique.

Effects of thyrotropin-releasing hormone in the fetal lamb.

Thyrotropin-releasing hormone causes neurobehavioral arousal and stimulates breathing in adult, newborn, and preterm experimental animals. Its effects on behavioral state, breathing, blood pressure, and heart rate were studied in the chronically instrumented late term fetal lamb. Fetal intravenous administration of thyrotropin-releasing hormone resulted in behavioral arousal with electrocortical desynchronization, increased body and eye movements, rapid and deep breathing movements, and a transient bradycardia followed by prolonged tachycardia, associated with an increase in both systolic and diastolic blood pressure. The effects were similar following intracisternal administration of thyrotropin-releasing hormone. The effects of thyrotropin-releasing hormone on behavior, but not breathing, was abolished in the presence of muscarinic blockade. Thyrotropin-releasing hormone may play a role in the modulation of central regulation of cardiovascular, respiratory, and behavioral activity in the fetus.

The relationship between maternal and fetal plasma protein binding of methadone in the ewe during the third trimester.

The binding of methadone to maternal and fetal plasma proteins was determined throughout the third trimester in the pregnant ewe. Blood was sampled from chronic indwelling catheters placed in the maternal aorta and fetal aorta. Methadone binding was determined by use of equilibrium dialysis with (3H)-methadone. Maternal binidng ranged from 50.4 to 89.5%, with a mean of 76.2 +/- 1.3 (SE)%. Fetal binding was initially significantly lower than maternal binding, but increased rapidly in the last two weeks before parturition. Prior to 130 days gestation, the ratio of fetal binding to maternal binding was 0.40 +/- 0.03. This binding ratio increased to 0.82 +/- 0.08 in the last few days of pregnancy. Preliminary results suggested that maternal binding was higher in the early post-partum period. These results demonstrate that the relationship between maternal and fetal plasma binding of methadone changes rapidly towards the end of pregnancy, and fetal binding approaches maternal binding at parturition.