Marrow Conversion Pattern of the Femora and Acetabulum Around Hip Joints According to Age Group : MR Evaluation

PURPOSE : Marrow edema and fatty degeneration of the hip joint bones could be initial and late signs inip joint and its bone diseases respectively, which might be differentiated from age-related marrow conversion pattern. So authors have investigated normal marrow conversion pattern of the femur and acetabulum around the hip joints. MATERIALS AND METHODS : Three coronal MR images of 288 hip joint bones in 144 subjects, aged 2 days to 76 years divided to 8 groups every 10 years, were retrospectively analysed for the location and appearance of the converted yellow marrow. The converted yellow marrow were divided to head, neck, and trochanter in the proximal femur and below and above 50% in acetabulum of the hip. RESULTS : The most common type of marrow conversion is the converted yellow marrow in the entire proximal femur and below 50% of acetabulum of the hip. We observed the start of marrow conversion in just before and after 2 years old and stopped at just before and after 20 years old. CONCLUSION : The understanding of age-related marrow conversion pattern of the hip joint bones would provide some information for differentiation from pathologic condition of them such as edema, fatty degeneration, metastasis, or leukemia.

HRCT Finding of Pulmonary Cryptococcosis in Immune Competent Patients

PURPOSE: To determine the HRCT finding of pulmonary cryptococcosis in immunocompetent patients. MATERIALS AND METHODS: The HRCT scans and chest radiographs of five patients with pulmonary cryptococcosis were retrospectively reviewed, the diagnosis being proven by the presence of the organism in histopathologic specimens obtained during CT-guided biopsy (n = 4) or medistinoscopic biopsy (n = 1). All patients were immunocompetent. HRCT scans and chest radiographs were characterized according to morphology [consoli-dation, nodule, ground-glass opacity (GGO), interstitial thickening], location, airbronchogram, and the pres-ence or absence of mediastinal or hilar lymphadenopathy. RESULTS: Consolidation was present in three of five patients, and in two of the three, ill-defined, spiculated nodules were also present. One patient had multiple, small, well-defined nodules. One had diffuse interstitial thickening (GGO, nodular thickening of bronchovascular bundles and interlobular septa), with massive mediastinal and right hilar lymphadenopathy. The location of the consolidation and nodules was mainly peripheral, and in three patients with consolidation, the presence of air bronchograms was noted. CONCLUSION: The HRCT findings of pulmonary cryptococcosis in immunocompetent patients are peripheral consolidation with airbronchogram and/or ill defined nodules.

Misregistration Artifact due to Respiratory Motion on Spiral CT of the Liver

PURPOSE: To determine the frequency and patterns of respiratory-induced misregistration artifact seen on spiral CT of the liver. MATERIALS AND METHODS: Two hundred patients with hepatic mass underwent spiral CT, and arterial phase images were compared with those of the portal phase in all cases and or of the delayed phase in 138. The patterns of misregistration artifact were divided into two groups: skipping, where at least two slices in the craniocaudal length of the mass were missed, and the partial volume veraging artifact thus excluded; and overlapping, where the same or reversed images were seen in succeeding sequences. We reviewed the location and size of the masses, and the presence or absence, and patterns of the misregistration artifact. RESULTS: Fourteen (7%) of 200 spiral CT scans demonstrated the misregistration artifact; in five of these there was skipping (involving a hepatic mass larger than 2 cm in two cases, and one smaller than 2 cm in three cases), and in nine there was overlapping (six masses larger than 2 cm, and three smaller than this). A lipiodol-laden mass measuring 5 mm was completely missed during the arterial phase. and in one case the spleen sequence was reversed. Thirteen (93%) of fourteen masses were located in the right lobe. CONCLUSION: Two patterns of misregistration artifact, skipping and overlapping, were observed, and their combined frequency was 7%. So as not to miss small hepatic masses or overestimate their size, careful respiratory control is therefore needed.

Usefulness of Enteral Contrast Media in MR Evaluation of Pelvic Mass

PURPOSE: To assess the value of enteral contrast media for the evaluation of pelvic masses by MR imaging. MATERIALS AND METHODS: Between April and July 1998, 16 women with pelvic masses were examined by MRI. The origin of the lesion was the ovary in twelve cases, the uterus in three, and the sigmoid in one. Using a 1.5T scanner(Magnetom Vision, Siemens), T1-weighted axial spin echo(SE), T2-weighted turbo spin echo(TSE), two-dimensional fast low-angle shot(FLASH 2D), and half-Fourier TSE(HASTE) images were obtained in all patients after the administration of Magnevist Enteral (Shering, Berlin, Germany). In each MR imaging sequence, distinction between the lesion and adjacent bowel (1, not distinguished; 2, partly distinguished; 3, clearly distinguished), artifact (0, absent; 1, mild; 2, severe), image quality (1, poor; 2, fair; 3, good), were compared before and after the use of enteral contrast media. Changes in MRI impression after the use of enteral contrast media were also evaluated. Two radiologists reached a consensus after reviewing the images. Statistical significance was determined by Wilcoxon's signed ranked test. RESULTS: For distinguishing lesions, SE T1WI and FLASH 2D with enteral contrast media were significantly superior to SE T1WI without enteral contrast media (p<0.05). With regard to image quality, FLASH 2D and HASTE, both with enteral contrast media, were significantly superior to SE T1WI and TSE T2WI, respectively, both without enteral contrast media (p<0.05). Artefacts were more frequently found after the application of enteral contrast media in conventional sequences but were not present in breathhold sequences. In two patients, MRI impression changed after the appilication of enteral contrast media. CONCLUSION: In a limited number of cases, enteral contrast media improved lesion detection, image quality and diagnostic accuracy when breathhold fast MR imaging was applied.

Usefulness of Ultrasonography in follow-up evaluation after Ilizarov Procedure: Comparison with PlainRadiography

PURPOSE: To compare the usefulness of ultrasonography in follow up evaluation after the Ilizarov procedurewith that of plain radiography. MATERIALS AND METHODS: We analyzed ultrasound findings in twelve patients who hadundergone the Ilizarov procedure, and retrospectively compared the results with the findings of plain radiography.The procedure was performed due to post-traumatic limb deformity or non-union(nine of twelve patients), congenitalpseudoarthrosis(one case), sequelae of poliomyelitis(one case), and short stature(one case). The patients' meanage was 29 years ; eleven of twelve were male. Ten of twelve procedures were performed on the tibia and two on thefemur. After 7-10 days, distraction was initiated at a rate of 0.25mm four times a day. Ultrasonography wasperformed with a 5-10 MHz linear or convex transducer ; new bone formation was defined as dotted or linearechogenic foci within a hypoechoic distraction gap. Initial ultrasonographic examination was performed 2-4 weeksafter distraction, and the results were compared with those of plain radiography. Color Doppler imaging wasperformed in three cases. RESULTS: On ultrasonograms, new bone formation was initially detected 18-29(mean, 23)days after distraction, and on plain radiographs, 37-58(mean, 45) days after this procedure ; ultrasonography thusdetected new bone formation at least three weeks earlier than did plain radiography. Complication after theIlizarov procedure were four cysts at the distraction site, and one pin site infection, as seen on ultrasonograms.None of these four cysts, the size of which was 12-22mm(mean, 17mm), was visible on plain radiographs. In one casein which a cyst was present, ultrasound-guided aspiration was performed. Color Doppler examination was performedin three of twelve patients, and in all three, periosteal vascularity at the edge of the distracted gap was seento be preserved. CONCLUSION: After the Ilizarov bone lengthening procedure, ultrasound appears to be useful forfollow-up examination. New bone formation, as well as complications, can be detected earlier ; it can indicatewhether ultrasound-guided interventional procedure is required, and if combined with color Doppler study, is ableto detect the periosteal blood supply. Further evaluation of the clinical significance of preserved periostealblood supply seems however, to be needed.

Usefulness of Automated Biopsy Guns in Image-guided Biopsy

PURPOSE: To evaluate the usefulness of automated biopsy guns in image-guided biopsy of lung, liver. pancreas and other organs. MATERIALS AND METHODS: Using automated biopsy devices, 160 biopsies of variable anatomic sites were performed:Biopsies were performed under ultrasonographic(US) guidance in 95 and computed tomographic (CT) guidance in 65. We retrospectively analyzed histologic results and complications. RESULTS: Specimens were adequate for histopathologic diagnosis in 143 of the 160 patients(89.4%)-Diagnostic tissue was obtained in 130 (81.3%), suggestive tissue obtained in 13(8.1%), and non-diagnostic tissue was obtained in 14(8.7%). Inadequate tissue was obtained in only 3(1.9%). There was no statistically significant difference between US-guided and CT-guided percutaneous biopsy. There was no occurrence of significant complication. We have experienced mild complications in only 5 patients-2 hematuria & 2 hematochezia in transrectal prostatic biopsy, and 1 minimal pneumothorax in CT-guided percutaneous lung biopsy. All of them were resolved spontaneously. CONCLUSION: The image-guided biopsy using the automated biopsy gun was a simple, safe and accurate method of obtaining adequate specimen for the histopathologic diagnosis.

Usefulness of Dynamic Magnetic Resonance Imaging in Brain Tumors

PURPOSE: To investigate the usefulness of dynamic MR imaging in the differential diagnosis of brain tumors. MATERIALS AND METHODS: Dynamic MR imaging was performed in 43 patients with histopathologically proved brain tumrs. Serial images were sequentially obtained every 30 seconds for 3--5 minutes with use of spin-echo technique(TR 200msec/TE 15msec) after rapid injection of Gd-DTPA in a dose of 0.1mmol/kg body weight. Dynamics of contrast enhancement of the brain tumors were analyzed visually and by the sequential contrast enhancement ratio(CER). RESULTS: On the dynamic MR imaging, contrast enhancement pattern of the gliomas showed gradual increase in signal intensity(SI) till 180 seconds and usually had a longer time to peak of the CER. The SI of metastatic brain tumors increased steeply till 30 seconds and then rapidly or gradually decreased and the tumors had a shorter time to peak of the CER. Meningiomas showed a rapid ascent in SI till 30 to 60 seconds and then made a plateau or slight descent of the CER. Lymphomas and germinomas showed relatively rapid increase of Sl till 30 seconds and usually had a longer time peak of the CER. CONCLUSION: Dynamic MR imaging with Gd-DTPA may lead to further information about the brain tumors as the sequential contrast enhancement pattern and CER parameters seem to be helpful in discriminating among the brain tumors.