MR imaging of the anterior cruciate ligament: frequency of discordant findings on sagittal-oblique images and correlation with arthroscopic findings

OBJECTIVE: The purposes of this study were to determine the frequency of discordant MR findings of the anterior cruciate ligament (ACL) using sagittal-oblique images and the arthroscopic integrity of the ACL in knees with a discordant MR appearance. MATERIALS AND METHODS: The frequency of discordant MR features was determined by independently reviewing the sagittal-oblique images of 53 consecutive patients undergoing subsequent arthroscopic surgery. The first 25 consecutive knees were examined using a conventional, dual-echo, T2-weighted spin-echo (SE) sequence; the subsequent 28 consecutive knees were examined using both a T1-weighted SE(T1) and a fat-suppressed, fast spin-echo (FSE) T2-weighted sequence. Two examiners who were unaware of patient identification and arthroscopic results evaluated only the sagittal images that included the ACL. Each reviewer graded the ACL as torn or intact. The MR appearance was considered discordant when one MR sequence showed disrupted or poorly seen ACL fibers and the other sequence showed intact ACL fibers. The arthroscopic integrity of the ACL was determined for the 20 knees with a discordant MR appearance. RESULTS: A discordant MR appearance of the ACL was seen in 20 of the 53 knees (38%), including 10 knees evaluated using conventional T2-weighted sequences (40%) and 10 knees using T1/FSE T2 (36%) sequences. Arthroscopic examination of these knees showed intact ACL fibers in all 20 knees; the ACL was normal in 18 knees and a partial tear was questioned in two knees. CONCLUSION: A discordant appearance of the ACL was frequently encountered (38%) using either conventional T2-weighted sequences or T1 and FSE MR sequences in the sagittal-oblique plane. Intact ACL fibers were found during arthroscopy in all 20 knees with a discordant MR appearance.     

Non-breath-hold fast spin-echo versus breath-hold fast spin-echo and spoiled gradient-recalled echo MR imaging in the detection of hepatic tumors: correlation with surgical findings

OBJECTIVE: Our objective was to compare the sensitivity of non-breath-hold T2-weighted fast spin-echo with and without fat suppression, breath-hold T2-weighted fast spin-echo without fat suppression, and spoiled gradient-recalled echo (GRE) MR imaging for detecting hepatic tumors using surgical findings as the standard of reference. SUBJECTS AND METHODS: Eighteen patients with 36 surgically proven hepatic tumors had non-breath-hold T2-weighted fast spin-echo (6000/117 [TR/effective TE; echo train length, 16) MR imaging with and without fat suppression, breath-hold T2-weighted fast spin-echo MR imaging (2700/105; echo train length, 20), and spoiled GRE images (10.1/1.9; flip angle, 30 degrees) obtained before and after injection of a gadolinium chelate. Images were analyzed separately by two independent readers, with disagreements resolved by consensus reading. RESULTS: Non-breath-hold T2-weighted fast spin-echo MR imaging with and without fat suppression depicted 22 (61%; 95% confidence interval [CI], 43-77%) and 20 (56%; 95% CI, 37-72%) of 36 hepatic tumors, respectively. Breath-hold T2-weighted fast spin-echo imaging allowed detection of 19 (53%; 95% CI, 35-69%) of 36 hepatic tumors. Unenhanced and gadolinium chelate-enhanced spoiled GRE images allowed depiction of 18 (50%; 95% CI, 33-67%) and 29 (81%; 95% CI, 63-91%) of 36 hepatic tumors, respectively. Gadolinium chelate-enhanced spoiled GRE images allowed depiction of significantly more hepatic tumors than any of the other pulse sequences. CONCLUSION: Gadolinium chelate-enhanced spoiled GRE imaging is more sensitive than T2-weighted MR imaging obtained with a breath-hold or a non-breath-hold technique.     

Anterior cruciate ligament injury in elite Alpine competitors

Balance in Alpine skiing is dynamic and tenuous. Loss of balance typically leads to the accumulation of forces that create severe bending moments at the knee. The modern ski binding, while effective at protecting the ankle and lower leg, is much less effective at protecting the knee. The result: knee injuries have increased nearly three-fold since 1972 with anterior cruciate ligament (ACL) injuries currently accounting for approximately 10% of all skiing injuries. The mechanism of ACL injury in elite competitors is distinct from recreational skiers and is typically associated with a characteristic, deeply flexed, seated body position, with the feet accelerating forward relative to the upper body. The risk of ACL injury in elite skiers is compounded by the functional characteristics of the modern ski binding and further exacerbated by the protocols used to set release tension for competition. It is apparent that the physical abilities of the elite competitor, combined with modern ski technique and equipment, expose the skier to forces that the human body cannot tolerate. Presently, the only solution to the problem would appear to be the development of "smarter" bindings and/or the adoption of standards that set limitations on performance for the sake of safety.     

T2-weighted spin-echo MR imaging of the liver: breath-hold fast spin-echo versus non-breath-hold fast spin-echo images with and without fat suppression

OBJECTIVE: The goal of our study was to compare a T2-weighted breath-hold fast spin-echo (BHSE) technique with T2-weighted non-breath-hold fast spin-echo techniques for imaging the liver. SUBJECTS AND METHODS: Thirty-three patients with hepatic lesions had T2-weighted BHSE images obtained in 22 sec and conventional T2-weighted non-breath-hold fast spin-echo images obtained in 3 min 12 sec with and without fat suppression. Images were analyzed quantitatively by measuring the lesion-liver contrast, spleen-liver contrast, and signal-to-noise ratios of lesions and qualitatively by evaluating the sharpness of hepatic contours, visibility of intrahepatic vessels and other segmental landmarks, and presence of artifacts. RESULTS: Quantitatively, lesion-liver contrast, spleen-liver contrast, and signal-to-noise ratios obtained with the BHSE technique were inferior to those obtained with fast spin-echo techniques with and without fat suppression (11.2 +/- 7.1 versus 15.4 +/- 10.6 and 14.5 +/- 9.8, p < .001; 5.3 +/- 3.7 versus 8.7 +/- 3.5 and 7.0 +/- 3.8, p < .001; 16.2 +/- 8.2 versus 20.1 +/- 10.9 and 19.7 +/- 9.5, p < .01, respectively; Student's t test). Qualitatively, image artifacts and intrahepatic vessel depiction on BHSE images were similar to those obtained with the fast spin-echo techniques. The BHSE technique was superior to fat-suppressed fast spin-echo technique for showing hepatic contours (p < .01; Wilcoxon signed-rank test). CONCLUSION: The BHSE technique is quantitatively inferior to non-breath-hold fast spin-echo techniques. However, further studies with a surgical standard of reference are needed to compare the three techniques in terms of sensitivity.     

Diffusion-weighted MR microscopy with fast spin-echo

A diffusion-weighted fast spin-echo (FSE) imaging sequence for high-field MR microscopy was developed and experimentally validated in a phantom and in a live rat. Pulsed diffusion gradients were executed before and after the initial 180 degrees pulse in the FSE pulse train. This produced diffusion-related reductions in image signal intensity corresponding to gradient ("b") factors between 1.80 and 1352 s/mm2. The degree of diffusion weighting was demonstrated to be independent of echo train length for experiments using trains up to 16 echoes long. Quantitative measurements on a phantom and on a live rat produced diffusion coefficients consistent with literature values. Importantly, the eight- to 16-fold increase in imaging efficiency with FSE was not accompanied by a significant loss of spatial resolution or contrast. This permits acquisition of in vivo three-dimensional data in time periods that are appropriate for evolving biological processes. The combination of accurate diffusion weighting and high spatial resolution provided by FSE makes the technique particularly useful for MR microscopy.     

Multishot echoplanar MR imaging of the female pelvis: comparison with fast spin-echo MR imaging in an initial clinical trial

OBJECTIVE: The purpose of this study was to apply multishot echoplanar MR imaging (EPI) to the female pelvis and compare image quality with that of fast spin-echo MR imaging. SUBJECTS AND METHODS: Twenty-one patients with suspected pelvic disease and five healthy female volunteers were prospectively examined. MR imaging was obtained using an EPI-capable 1.0-T imager and a pelvic phased-array coil. Axial EPI and fast Spin-echo sequences were obtained at identical image locations in each patient and volunteer. Spin-echo EPI images were obtained using a multishot number of 16. Acquisition time for each EPI sequence was 2 min 10 sec. Fat-suppressed T2-weighted fast spin-echo images were obtained in 2 min 12 sec. Paired EPI and fast spin-echo MR images were independently evaluated by three reviewers. RESULTS: Delineation of the perivaginal and parametrial venous plexus on EPI was rated superior to the fast spin-echo images in 62 (77%) of 81 cases. On EPI, uterine zone anatomy and ovary visualization were judged to be inferior in 44 (56%) of 78 cases and in 18 (33%) of 54 cases, respectively. For delineation of uterine abnormalities, including leiomyoma and adenomyosis, both sequences performed almost equally well. However, ovarian cystic lesions were revealed more precisely by the fast spin-echo sequence. An overall fat-suppression effect was seen on EPI images in 62 (77%) of 81 cases. CONCLUSION: Multishot EPI cannot replace fast spin-echo sequences for imaging the female pelvis; however, because EPI has a potent fat-suppression effect and heavily T2-weighted contrast, EPI sequences can be a valuable adjunct to routine examination.     

SPLICE: sub-second diffusion-sensitive MR imaging using a modified fast spin-echo acquisition mode

Recent human studies for measuring of the apparent diffusion coefficient in tissue by magnetic resonance imaging have been conducted by time-consuming standard spin-echo acquisition sequences and phase correction with navigator echoes. Diffusion-weighted echo-planar sequences have been shown to be rapid alternatives for brain imaging. Both methods show inherent disadvantages in applications on thoracic or abdominal sites. A new approach combining single-shot diffusion-weighted imaging with a modified fast spin-echo acquisition mode is reported here. The modification is necessary, because normal fast spin-echo acquisition requires a particular phase relation between the magnetization and the refocusing pulses. Unfortunately, this phase relation is not provided after diffusion sensitive preparation. Therefore, the split echo acquisition mode was developed and is shown to be insensitive to the phase of the magnetization. The advantages of both fast spin-echo acquisition and diffusion weighting can be combined in the SPLICE sequence (split aqcuisition of fast spin-echo signals for diffusion imaging). The applicability of the new technique is shown by series of sub-second diffusion-weighted images from different parts of the body.     

Half-fourier acquisition single-shot turbo spin-echo (HASTE) MR: comparison with fast spin-echo MR in diseases of the brain

PURPOSE: To compare an ultrafast T2-weighted (half-Fourier acquisition single-shot turbo spin-echo [HASTE]) pulse sequence with fast spin-echo T2-weighted sequences in MR imaging of brain lesions. METHODS: Fast spin-echo and HASTE images of 34 consecutive patients over the age of 50 years or with suspected demyelinating disease were reviewed independently by two neuroradiologists for the number of lesions less than 5 mm and greater than or equal to 5 mm, and for lesion conspicuity, gray-white matter differentiation, and extent of periventricular confluent signal abnormality. The reviewers also assessed for the presence of hemosiderin and extent of motion artifacts. RESULTS: Per patient, the mean number of 5-mm or larger lesions detected on fast spin-echo images (1.4) relative to the number detected on HASTE images (0.8) was not statistically significant. For lesions less than 5 mm, fast spin-echo images showed more lesions (7.5) than HASTE images did (2.4). The fast spin-echo images were better at depicting gray-white matter differentiation, conspicuity of lesions, and periventricular signal abnormality. Of four T2 hypointense lesions seen on fast spin-echo images, none was detected on HASTE images. CONCLUSION: Although the HASTE technique might be useful for rapid imaging of the brain, our study shows a diminished sensitivity for the detection of lesions less than 5 mm in diameter and for T2 hypointense lesions.     

Anterior knee laxity and loss of extension after anterior cruciate ligament injury

This study was performed to examine the relationship between knee extension loss and the length of time after injury. We also wanted to compare anterior laxity in anterior cruciate ligament-injured knees in the early and late stages of injury. Loss of knee extension was measured in 81 patients with anterior cruciate ligament injury using lateral radiography with the injured leg relaxed and elevated. Extension loss was defined as the difference in maximal extension angle between the injured and uninjured knees. Average loss of extension was 3.6 degrees in the 17 knees in which the anterior cruciate ligament had been torn 3 weeks or less before examination (the acute injury group) and 0.6 degree in the 64 knees in which the anterior cruciate ligament had been torn more than 3 weeks before examination (the chronic injury group). The extension loss in the acutely injured knees was significantly greater compared with that in the uninjured knees and in the chronically injured knees. Arthrometric measurements using the KT-1000 arthrometer were reliable to diagnose an acute tear. There was no correlation between the degree of extension loss and arthrometric anterior knee laxity measurements. In 12 patients, the initial extension deficit in the early stage of injury significantly resolved with time, and manual maximum arthrometric measurements of anterior knee laxity improved spontaneously with time.     

Anterior cruciate ligament reconstruction: endoscopic versus two-incision technique

The purpose of this study was to compare the single-incision, "endoscopic" (ENDO) anterior cruciate ligament (ACL) reconstruction technique with the two-incision, "rear-entry" technique (RE). Sixty patients were entered into a prospective study. Thirty patients underwent ACL reconstruction by the RE technique, followed by 30 consecutive patients using the ENDO procedure. Postoperatively all patients followed a standardized rehabilitation protocol. Follow-up evaluation consisted of a detailed physical examination, range of motion, thigh girth, vertical leap, hop test, KT-1000 testing, and patient interview. They were scored according to the International Knee Documentation Committee (IKDC) protocol, which takes objective and subjective data into account. Patients were also assessed for level of sports activity including frequency and type. Finally, anteroposterior and lateral x-ray films were evaluated with a scoring system for tunnel location. Of the initial 60 patients entered into the study, 50 were available for a detailed clinical and functional review (83%). Demographic comparisons revealed 24 RE patients and 26 ENDO patients. There were 16 men and 8 women in the RE group. The ENDO group comprised 16 men and 10 women. There were 14 right knees and 10 left knees in the RE group. In the ENDO group there were 13 right knees and 13 left knees. The average age in the RE group was 24 years and 25 years in the ENDO group. The average follow-up was 35 months (range 31-40 months) in the RE group and 29 months (range 24-35 months) in the ENDO group. Complications included two patients with loss of motion in the RE group and three in the ENDO group. There were no significant differences between the two groups tested with respect to the overall IKDC rating scale. Anteroposterior and lateral x-ray films revealed no significant differences in femoral and tibial tunnel placement. In conclusion, no significant functional or radiographic differences at a minimum 2-year follow-up could be identified when comparing the two ACL reconstructive techniques.     

Hepatic cavernous hemangioma: appearance on T2-weighted fast spin-echo MR imaging with and without fat suppression

OBJECTIVE: The goals of our study were to define the morphologic appearance of cavernous hemangioma of the liver on T2-weighted fast spin-echo MR imaging and to determine if the use of fat suppression may quantitatively and qualitatively modify the MR imaging appearance of cavernous hemangioma. SUBJECTS AND METHODS: Twenty-six patients with cavernous hemangiomas of the liver were prospectively studied with T2-weighted MR imaging with a fast spin-echo technique with and without fat suppression. Thirteen patients had known hemangiomas for more than 2 years, with no change in size or morphology during this period. The remaining 13 patients had diagnoses based on dynamic CT and sonography and an absence of change in the morphology and size of their lesions during follow-up of more than 6 months (range, 6-12 months) after the MR imaging studies. Values for signal intensity and contrast-to-noise (C/N) ratios in cavernous hemangiomas that were obtained with and without fat suppression were compared. Images were qualitatively analyzed separately at identical level and window settings by two interpreters for morphologic features of cavernous hemangiomas. RESULTS: No significant difference was found between signal intensity values obtained using the fat-suppressed fast spin-echo MR imaging technique (5.62 +/- 1.14 [SD]) and those obtained without fat suppression (5.51 +/- 1.23). Values for C/N ratios obtained with the fat-suppressed fast spin-echo MR imaging technique (20.13 +/- 7.63) were significantly superior to those obtained without fat suppression (16.59 +/- 5.31) (p < .001). On T2-weighted fast spin-echo MR imaging without fat suppression, 100% of cavernous hemangiomas were hyperintense relative to the spleen, 90% had well-defined and sharp margins, 55% were isointense to CSF, and 76% were homogeneous. Without fat suppression, 34% of cavernous hemangiomas showed the combination of isointensity to CSF, well-defined margins, and homogeneity. On T2-weighted fast spin-echo MR imaging with fat suppression, all cavernous hemangiomas showed this same combination of features. CONCLUSION: Seventy-six percent of hepatic cavernous hemangiomas were homogeneous on T2-weighted fast spin-echo MR imaging, and 55% were isointense to CSF. However, only 34% of hepatic cavernous hemangiomas showed typical features. Although fat suppression significantly increased the C/N ratio of cavernous hemangiomas of the liver, fat suppression did not affect their morphologic appearance on T2-weighted fast spin-echo MR imaging.     

Preoperative staging of endometrial carcinoma: diagnostic effect of T2-weighted fast spin-echo MR imaging

PURPOSE: To evaluate the usefulness of T2-weighted fast spin-echo magnetic resonance (MR) imaging with a 512 x 256 matrix for assessment of the preoperative stage of endometrial carcinoma. MATERIALS AND METHODS: Twenty-eight women with histopathologically proved endometrial carcinoma underwent preoperative T2-weighted fast spin-echo, dynamic T1-weighted fast spin-echo, and postcontrast T1-weighted spin-echo MR imaging with a phased-array surface coil. The uterine long-axis planes in each sequence were reviewed at separate sessions by three radiologists blinded to the histopathologic data. RESULTS: For the diagnosis of myometrial invasion, no statistically significant differences were found among T2-weighted imaging, dynamic imaging, and postcontrast T1-weighted imaging. For the diagnosis of deep myometrial invasion, T2-weighted and dynamic images showed higher specificity than postcontrast T1-weighted images (T2-weighted, 89%; dynamic, 88%; and postcontrast T1-weighted, 80%). For cervical invasion, T2-weighted and dynamic images showed larger areas under receiver operating characteristic curves than did postcontrast T1-weighted images (T2-weighted, 0.78; dynamic, 0.71; and postcontrast T1-weighted, 0.67). CONCLUSION: T2-weighted imaging is useful for identifying the stage of endometrial carcinoma.     

Breath-hold fast spin-echo MR imaging of the liver: a technique for high-quality T2-weighted images

The added technical complexity associated with the transfixion screws for interlocking nailing has introduced new complications. We present a case of a femoral arteriovenous fistula caused by the distal interlocking screw after intramedullary nailing of a comminuted diaphyseal femoral fracture.     

Anterior cruciate ligament tears in athletes: assessment and clinico-diagnostic control with a dedicated system

The hydroxyapatite implant (Bio-Eye, Intergrated Orbital Implant, Inc., San Diego, CA, U.S.A.) has gained increasing popularity as an orbital implant in recent years. Several complications may occur, including infection, exposure, extrusion, and various peg problems. Exposure of the implant appears to be the most common complication, ranging up to 21.6%. Many techniques, including nonsurgical and surgical approaches, have been described to manage these exposures. When surgery is indicated, a patch graft may be required to cover the defect. We report our experience and technique with autogenous temporalis fascia as a patch graft. Autografts such as temporalis fascia are easily obtained, bring about no immunological reaction, and have no risk of infectious transmission.     

Anterior cruciate ligament reconstruction with autogenous patellar tendon graft in patients with articular cartilage damage

To test if anterior cruciate ligament reconstruction with autogenous patellar tendon can alleviate symptoms and functional limitations and increase activity levels in patients with advanced articular cartilage damage, we looked at 53 patients with arthroscopically documented cartilage damage. In this group, a mean of 7.5 years had elapsed between the original injury and the reconstruction, and 90 prior operative procedures had been done. Postoperatively, all patients had immediate motion and early functional rehabilitation. The results were assessed with the Cincinnati Knee Rating System. At followup (mean, 27 months), significant improvements were found for pain, swelling, giving way, functional limitations with daily and sports activities, and the overall rating score. Forty-two patients (79%) had returned to some type of athletic activity. Only three patients (6%) had failed results. In the patients' own ratings of the overall knee condition, 8 of 51 (16%) rated their knees as normal, 28 (55%) as very good, 7 (14%) as good, 5 (10%) as fair, and 3 (6%) as poor. We concluded that the majority of patients benefited from the arthroscopically assisted anterior cruciate ligament reconstruction because it decreased episodes of giving way with daily activities and increased activity without aggravating the preexisting arthrosis.     

Delineation of small nerves and blood vessels with three-dimensional fast spin-echo MR imaging: comparison of presurgical and surgical findings in patients with hemifacial spasm

BACKGROUND AND PURPOSE: We applied a 3D fast spin-echo (3D-FSE) MR imaging technique to the preoperative and postoperative evaluation of patients with hemifacial spasm. METHODS: The study group comprised 20 patients. All images were acquired on a 1.5-T MR system with a 3D-FSE sequence. RESULTS: In all 20 patients, the courses of the seventh and eighth cranial nerves were depicted separately, and the arteries presumed to be responsible for the hemifacial spasm were seen to be in contact with the facial nerves at the root exit zone (REZ). Eight patients underwent neurovascular decompression. In all patients, the presumed responsible blood vessels depicted by 3D-FSE MR imaging corresponded to intraoperative findings. In addition, postoperative 3D-FSE images confirmed the separation of the facial nerve from a contiguous vessel at the REZ. DISCUSSION: The 3D-FSE technique makes it possible to obtain extremely high-quality images of microstructures in the cerebellopontine cistern, and it has several advantages over conventional angiography: it is noninvasive and able to depict the cranial nerves and surrounding vessels in the same image without contrast material, and it may be useful for postoperative evaluation of the decompression procedure. This imaging technique is expected to prove useful for the clinical evaluation of hemifacial spasm.     

Inner ear volumetric measurements using high-resolution 3D T2-weighted fast spin-echo MR imaging: initial experience in healthy subjects

BACKGROUND AND PURPOSE: Adult size is achieved in the inner ear labyrinth by approximately 25 weeks' gestation, and minimal variability in age, sex, side, and race is found after birth. In this study, we opted to determine the reproducibility of inner ear volumetric measurements generated from high-resolution heavily T2-weighted 3D fast spin-echo MR images. METHODS: The temporal bones of 23 volunteers were imaged using a heavily T2-weighted 3D fast spin-echo MR imaging technique. The images were assessed by a neuroradiologist for the presence of inner ear configurational anomalies and, most important, for complete coverage of the inner ear labyrinth. Subsequently, the volume of the fluid in the inner ear was determined by two observers using a semiautomated segmentation algorithm. The mean, SD, range, and coefficient of variation of fluid volume in the inner ear were calculated. Age-, sex-, and side-related differences in the inner ear volumetric measurements were evaluated using analysis of variance. Interrater consistency in the inner ear volumetric measurements was evaluated by comparing the calculated coefficients of reliability. RESULTS: Volumetric measurements were available from 46 inner ears in 23 volunteers. The mean volume was 227.8 mm3 (SD, 24.4 mm3), and the coefficient of variation was 10.7%. No age-, sex-, or side-related differences in the inner ear volumetric measurements were found (F ratios were 4.33, 5.04, and 0.26, respectively). Interrater consistency, as assessed by the coefficient of reliability, was 5.3%. CONCLUSION: Reproducible volumetric measurements of the inner ear labyrinth can be obtained by applying a semiautomated segmentation algorithm to a heavily T2-weighted 3D fast spin-echo MR imaging data set. These volumetric measurements may help identify patients with congenital sensorineural hearing loss and normal inner ear configuration.     

Hepatic lesions: discrimination of nonsolid, benign lesions from solid, malignant lesions with heavily T2-weighted fast spin-echo MR imaging

PURPOSE: To determine whether the combined use of heavily and moderately T2-weighted fast spin-echo magnetic resonance (MR) images improves differentiation of non-solid, benign hepatic lesions from solid malignancies. MATERIALS AND METHODS: Three radiologists reviewed moderately (n = 133) and heavily (n = 133) T2-weighted and multiphasic dynamic contrast material-enhanced (n = 93) MR images in 133 patients with proved focal hepatic lesions (95 benign, 38 malignant). The radiologists used a five-point scale to rate their confidence in determination of malignancy. RESULTS: All three reviewers were statistically significantly better able to differentiate small (diameter less than 3 cm; n = 84) benignancies from small malignancies with the combination of moderately and heavily T2-weighted images (area under the receiver operating characteristic curve, 0.99 for each reader) than with moderately T2-weighted images alone (area, 0.88-0.90; P < .05). Confident diagnoses were rendered in 69 (82%) patients, with 100% accuracy for the combined use of moderately and heavily T2-weighted images. For larger lesions (diameter 3 cm or larger; n = 49), accurate differentiation was possible with moderately T2-weighted images alone. Additional use of multiphasic images did not improve the sensitivity, specificity, or accuracy of image interpretation. CONCLUSION: The combined use of moderately and heavily T2-weighted fast spin-echo MR images improves differentiation of small benign hepatic lesions from small malignant lesions.     

Anterior cruciate ligament reconstruction with fresh-frozen patellar tendon allografts: sixty cases with 2 years'' minimum follow-up

The objective of the present study was to determine the effect on infection of wheat spikes by toxigenic fungi (Aspergillus parasiticus NRRL 2999, Fusarium tricinctum NRRL 3299, Fusarium graminearum CEREMIC 136/92) and a strain of Streptomyces sp. that is antagonistic to the above-mentioned fungi. Wheat grains (variety GRANERO INTA) were sown in 8 pots containing natural soil and kept in a greenhouse chamber. In the period of the early anthesis the wheat spikes were inoculated with conidial suspensions of each of the fungi in the presence or absence of Streptomyces. Each pot was assigned a different treatment. After an incubation of 100 days and when the wheat plants had attained maturity, the spikes were separated and the following items were determined: (a) number of grains obtained with each treatment, (b) weight of the grains, (c) average weight of the grains/treatment, (d) average number and weight of the grains/spike, and (e) invasion of the caryopses by the microorganisms determined by the analysis of the caryopses in seriate histological sections. There was a significant decrease (p < 0.01) in the average weight of the caryopses and in the weight and number of grains/spike in the presence F. graminearum. The wheat grains were invaded by of F. graminearum and A. parasiticus, an effect which was partially attenuated by the presence of antagonist Streptomyces sp. Nevertheless, the effect was not strong enough to prevent the degenerative consequences on the size and weight of the grains produced by F. graminearum.