MR Findings of Chondromalacia Patella: Correlation of the Grade and Associated Lesions with ArthroscopicFindings

PURPOSE: To assess the MR findings of chondromalacia patella and correlate the grade and associated lesionswith the arthroscopic findings. MATERIALS AND METHODS: Twenty-five patients with pain in the anterior part of theknee underwent fat-suppressed axial and coronal T2-weighted, dual echo sagittal proton density-weighted andT2-weighted, and in some cases, T1-weighted and T2*-weighted imaging, using a 10-cm field of view, and a 5-inchgeneral purpose coil. We retrospectively assessed these find dings, and the locations, grades and associatedlesions, and correlated these with the arthroscopic findings. RESULTS: Fourteen cases(56%) of chondromalaciapatellae were arthroscopic grade I / II, nine(36%) were grade III, and two(8%) were grade IV; associated lesionswere medial synovial plicae (16 cases, 64%), meniscus tear (10 ; 40%), cruciate ligament injury (two ; 8%),complete or incomplete discoid meniscus (four ; 16%), bipartite patella (one ; 4%) and Osgood-Schlatter disease(one ; 4%). In 24 cases, MR imaging indicated chondromalacia patella ; 17 cases were grade I / II, five were gradeIII, and two were grade IV. the location of chondromalacia patella was the medial facet (five cases ; 20%), lateralfacet (three ; 12%), junction of the medial and odd facet (13 ; 52%), and diffuse involvement (four ; 16%). Thesensivity and specificity of MR imaging were 72% and 96% respectively. CONCLUSION: We evaluated the exact locationand grade of chondromalacia patella and associated lesions, as seen on MR images. These and the arthroscopicfindings showed close correlation, and in cases involving this condition, MRI is thus a useful indicator of anappropriate surgical method and plan.

Hepatic Hemangioma with Atypical Sonographic Features: Value of Two-Phase Spiral CT

PURPOSE: The purpose of this study was to evaluate enhancement patterns, as seen on two-phase spiral CT, of hepatic hemangiomas in which atypical features had been seen on sonography (US) MATERIALS AND METHODS: Two-phase spiral CT scanning was performed in 18 patients in whom 24 atypical hemangiomas had been seen on US. Two-phase images were obtained at 25-45 seconds (arterial dominant phase) and 2-5 minutes (equilibrium phase) after the initiation of a bolus injection of contrast material (150 ml, 5 ml/sec). Enhancement patterns of hemangiomas during each phase were classified as homogeneous high, peripheral high, or low attenuation, and were retrospectively analyzed. RESULTS: In the arterial dominant phase of spiral CT, low attenuation was seen in nine hemangiomas (38%), globular or spotty peripheral high attenuation in 14 (58%), and homogeneous high attenuation in one (4%). In the equilibrium phase, enhancement patterns were peripheral high attenuation (partial fill-in) in 18 lesions (75%), and homogeneous high attenuation (complete fill-in) in three (12.5%), In the other three (12.5%) enhancement showed no significant change; in one of these, density was slightly less than in the arterial phase, and two showed subtle peripheral high attenuation. Fourteen hemangiomas (58%) showed globular or spotty peripheral high attenuation in the arterial dominant phase and peripheral or homogeneous high attenuation with progressive centripetal enhancement in the equilibrium phase. CONCLUSION: Our results suggest that two-phase spiral CT during the arterial dominant and equilibrium phase is useful in differentiating hepatic hemangiomas with atypical features seen on US from malignant hepatic tumors.

MR Imaging Findings of Ring Apophyseal Fractures in Lumbar Vertebrae

PURPOSE: To assess the location and associated findings of fractures of the posterior lumbar vertebral ring apophysis as seen on MRI. MATERIALS AND METHODS: We retrospectively evaluated MR findings in 77 patients (86 lesions) with lumbar apophyseal ring fractures. Their age ranged from ten to 67 (mean 33-1) years. To confirm the presence of verterbral ring fractures, CT was performed in 29 patients (31 lesions) within two weeks of MR imaging. Open laminectomy was performed in ten patients, percutaneous automated nucleotomy in three, and LASER operation in four. RESULTS: The most common location of fractures was the superior margin of L5 (36 lesions 41.9%), next was superior margin of S1 (21 lesions, 24.4%). On CT, a bony fragment was seen in 28 patients (30 lesions); the positive predictive value of MR was 99.7 %. Multiple lesions were seen in nine patients. Associated disc herniation and bulging were noted in 64 (74.4%) and 15 lesions (17.4%), respectively, and a high signal intensity rim aound the bony fragment on T1 weighted image was noted in 33 (38.4%). Other associated findings were spondylolysis in eight patients, retrolisthesis in five, and spondylolisthesis in three. Operative outcomes were variable. The results of open laminectomy were better than those of percutaneous automated laminectomy or LASER operation. CONCLUSION: In patients with lumbar apophyseal ring fractures, their exact location and associated findings could be evalvated by MRI, which was therefore useful in the planning of appropriate surgery.

MR Measurement of the Normal Corpus Callosum in Children

PURPOSE: To measure the mean size of the various portions of the corpus callosum in normal Korean children, using MR imaging. MATERIALS AND METHODS: Our subjects were 166 children (male : female=100 : 66) aged under 15 whose findings on MR imaging and neurologic examination were normal. Using midsagittal T1-weighted imaging, we measured the length of the brain and corpus callosum, the height of the latter, and the thickness of its genu, body, transitional zone and splenium. The measurements were statistically analysed according to age and sex. RESULTS: Brain length and the size of the various portions of the corpus callosum tended to increase relatively rapidly during the first three years of life, but the rate of growth tended to decrease according to age. The mean length of the brain and corpus callosum and the mean thickness of the splenium of the corpus callosum did not differ according to sex. The mean thickness of the genu, body and transitional zone of the corpus callosum was greater in males than in females. The ratio of the length of the corpus callosum to the anteroposterior diameter of the brain was significantly greater in females than in males (alpha = 0.05). CONCLUSION: Using MR imaging, we measured the mean sizes of the various portions of the corpus callosum in normal children ; these values may provide a useful basis for determing changes occurring in its structure.