Clinical Validation of a Deep Learning-Based Hybrid (Greulich-Pyle and Modified Tanner-Whitehouse) Method for Bone Age Assessment

Objective@#To evaluate the accuracy and clinical efficacy of a hybrid Greulich-Pyle (GP) and modified Tanner-Whitehouse (TW) artificial intelligence (AI) model for bone age assessment. @*Materials and Methods@#A deep learning-based model was trained on an open dataset of multiple ethnicities. A total of 102 hand radiographs (51 male and 51 female; mean age ± standard deviation = 10.95 ± 2.37 years) from a single institution were selected for external validation. Three human experts performed bone age assessments based on the GP atlas to develop a reference standard. Two study radiologists performed bone age assessments with and without AI model assistance in two separate sessions, for which the reading time was recorded. The performance of the AI software was assessed by comparing the mean absolute difference between the AI-calculated bone age and the reference standard. The reading time was compared between reading with and without AI using a paired t test. Furthermore, the reliability between the two study radiologists’ bone age assessments was assessed using intraclass correlation coefficients (ICCs), and the results were compared between reading with and without AI. @*Results@#The bone ages assessed by the experts and the AI model were not significantly different (11.39 ± 2.74 years and 11.35 ± 2.76 years, respectively, p = 0.31). The mean absolute difference was 0.39 years (95% confidence interval, 0.33– 0.45 years) between the automated AI assessment and the reference standard. The mean reading time of the two study radiologists was reduced from 54.29 to 35.37 seconds with AI model assistance (p < 0.001). The ICC of the two study radiologists slightly increased with AI model assistance (from 0.945 to 0.990). @*Conclusion@#The proposed AI model was accurate for assessing bone age. Furthermore, this model appeared to enhance the clinical efficacy by reducing the reading time and improving the inter-observer reliability.

The Association between the Magnetic Resonance Imaging Findings of Adhesive Capsulitis and Shoulder Muscle Fat Quantification Using a Multi-Echo Dixon Method

OBJECTIVE: To investigate the association between the magnetic resonance imaging (MRI) findings of adhesive capsulitis and shoulder muscle fat percentages using a multi-echo Dixon method. MATERIALS AND METHODS: Twenty-four patients with clinical diagnoses of adhesive capsulitis and either intact rotator cuffs or Ellman grade 1 partial tears as indicated by MRI scans were included. Two radiologists independently evaluated MRI scans of adhesive capsulitis as follows: presence or absence of axillary recess capsular and extracapsular hyperintensities; thickness of the coracohumeral ligament; thickness of abnormal rotator interval soft tissue; and thickness of glenoidal/humeral axillary recess capsules. Fat quantifications of the supraspinatus, infraspinatus, teres minor, subscapularis, teres major and posterior deltoid muscles were performed using multi-echo Dixon imaging at three locations. Inter-rater agreement was assessed. Differences in fat percentages were assessed and correlations between fat percentages and quantitative measurements were evaluated. RESULTS: The fat percentage of the supraspinatus was significantly higher in patients with extracapsular hyperintensity (present, 3.00 ± 1.74%; absent, 1.81 ± 0.80%; p = 0.022). There were positive correlations between the fat percentage of the teres minor and the thicknesses of the abnormal rotator interval soft tissue (r = 0.494, p = 0.014) and the glenoidal axillary recess capsule (r = 0.475, p = 0.019). After controlling for the effects of age, sex and clinical stage, the relationship between the teres minor fat percentage and the thickness of the abnormal rotator interval soft tissue was statistically significant (r = 0.384, p = 0.048). Inter-rater agreement was almost perfect for fat quantification (intraclass correlation coefficients [ICC] > 0.9) and qualitative analyses (k = 0.824), but were variable for quantitative measurements (ICC, 0.170–0.606). CONCLUSION: Several MRI findings of adhesive capsulitis were significantly related to higher fat percentages of shoulder muscles.

Healing Process of Osteonecrotic Lesions of the Femoral Head Following Transtrochanteric Rotational Osteotomy: A Computed Tomography-Based Study

BACKGROUND: Transtrochanteric rotational osteotomy (TRO) is a controversial hip-preserving procedure with a variable success rate. The healing process of femoral head osteonecrosis after TRO has been poorly explained till now. This study aimed to evaluate the healing process of previously transposed necrotic lesion after a TRO for nontraumatic osteonecrosis of the femoral head using computed tomography (CT). METHODS: Among 52 patients (58 hips) who had preserved original femoral head after TRO, we retrospectively reviewed 27 patients (28 hips) who had undergone sequential CT scans and had no major complication following TRO. The average age was 34 years (range, 18 to 59 years). The mean follow-up period was 9.1 years. We evaluated the reparative process of the transposed osteonecrotic lesion with CT scans. RESULTS: Plain radiographs of the osteonecrotic lesion revealed sclerotic and lucent changes in 14 hips (50%) and normal bony architecture in the other 14 hips (50%) at the final follow-up. CT scans of the osteonecrotic lesions showed cystic changes with heterogeneous sclerosis in 13 hips (46%), normal trabecular bone with or without small cysts in 9 hips (32%), and fragmentation of the necrotic lesion in 6 hips (22%). Seventeen hips (60%) showed minimal (13 hips) to mild (4 hips) nonprogressive collapse of the transposed osteonecrotic area. The collapse of the transposed osteonecrotic area on the CT scan was significantly associated with the healing pattern (p = 0.009), as all 6 patients (6 hips) with fragmentation of the necrotic lesion had minimal (5 hips) to mild (1 hip) collapse. Furthermore, a significant association was found between the collapse of the transposed osteonecrotic area on the CT scan of 17 hips (60%) and postoperative Harris hip score (p = 0.021). We observed no differences among the healing patterns on CT scans with regard to age, gender, etiology, staging, preoperative lesion type, preoperative intact area, percentage of necrotic area, direction of rotation and immediate postoperative intact area. CONCLUSIONS: The majority of the hips showed incomplete regeneration of the transposed osteonecrotic lesion with cysts, sclerosis, and fragmentation, whereas repair with normal trabecular bone was observed only in one-third of the hips that were preserved after Sugioka TRO.

Comparison of T1rho and T2 Mapping of Knee Articular Cartilage in an Asymptomatic Population

OBJECTIVE: To analyze subregional differences in T1rho (T1ρ) and T2 values and their correlation in asymptomatic knee cartilage, and to evaluate angular dependence with magic angles. MATERIALS AND METHODS: Six asymptomatic volunteers underwent knee MRI with T1ρ and T2 mapping. T1ρ and T2 values were measured by two radiologists independently, at nine subregions in the medial femoral condyle (MFC) cartilage, at angles of ± 0°, 15°, 35°, 55°, 75° respective to a vertical line (B0) bisecting the width of the distal femur, and at two locations in the patella. Subregional values of T1ρ and T2 were analyzed and significant differences in three divided portions of the MFC (anterior, central, and posterior) were statistically evaluated. Correlation between T1ρ and T2 and angular dependence with magic angles were also assessed for statistical significance. RESULTS: T1ρ values were lowest at +15° and highest at -55°. T2 values were lowest at +75° and highest at +35°. Both T1ρ and T2 were higher in superior patella than inferior patella. T1ρ showed significant differences in the three divided portions of the MFC, while T2 showed significant differences only between central and posterior portions. There was a weak correlation between T1ρ and T2 (r = 0.217, p = 0.127). T1ρ showed more angular dependence than T2. CONCLUSION: T1ρ and T2 showed different subregional values and angular dependence in asymptomatic knee cartilage with a weak correlation. Awareness of these differences will aid in assessment of cartilage in a specific subregion of the knee.

Detecting Peripheral Nerves in the Elbow using Three-Dimensional Diffusion-Weighted PSIF Sequences: a Feasibility Pilot Study

PURPOSE: To analyze the feasibility of three-dimensional (3D) diffusion-weighted (DW) PSIF (reversed FISP [fast imaging with steady-state free precession]) sequence in order to evaluate peripheral nerves in the elbow. MATERIALS AND METHODS: Ten normal, asymptomatic volunteers were enrolled (6 men, 4 women, mean age 27.9 years). The following sequences of magnetic resonance images (MRI) of the elbow were obtained using a 3.0-T machine: 3D DW PSIF, 3D T2 SPACE (sampling perfection with application optimized contrasts using different flip angle evolution) with SPAIR (spectral adiabatic inversion recovery) and 2D T2 TSE (turbo spin echo) with modified Dixon (m-Dixon) sequence. Two observers used a 5-point grading system to analyze the image quality of the ulnar, median, and radial nerves. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of each nerve were measured. We compared 3D DW PSIF images with other sequences using the Wilcoxon-signed rank test and Friedman test. Inter-observer agreement was measured using intraclass correlation coefficient (ICC) analysis. RESULTS: The mean 5-point scores of radial, median, and ulnar nerves in 3D DW PSIF (3.9/4.2/4.5, respectively) were higher than those in 3D T2 SPACE SPAIR (1.9/2.8/2.8) and 2D T2 TSE m-Dixon (1.7/2.8/2.9) sequences (P < 0.05). The mean SNR in 3D DW PSIF was lower than 3D T2 SPACE SPAIR, but there was no difference between 3D DW PSIF and 2D T2 TSE m-Dixon in all of the three nerves. The mean CNR in 3D DW PSIF was lower than 3D T2 SPACE SPAIR and 2D T2 TSE m-Dixon in the median and ulnar nerves, but no difference among the three sequences in the radial nerve. CONCLUSION: The three-dimensional DW PSIF sequence may be feasible to evaluate the peripheral nerves around the elbow in MR imaging. However, further optimization of the image quality (SNR, CNR) is required.

MR Findings of the Osteofibrous Dysplasia

OBJECTIVE: The aim of this study was to describe MR findings of osteofibrous dysplasia. MATERIALS AND METHODS: MR images of 24 pathologically proven osteofibrous dysplasia cases were retrospectively analyzed for a signal intensity of the lesion, presence of intralesional fat signal, internal hypointense band, multilocular appearance, cortical expansion, intramedullary extension, cystic area, cortical breakage and extraosseous extension, abnormal signal from the adjacent bone marrow and soft tissue and patterns of contrast enhancement. RESULTS: All cases of osteofibrous dysplasia exhibited intermediate signal intensity on T1-weighted images. On T2-weighted images, 20 and 4 cases exhibited heterogeneously intermediate and high signal intensity, respectively. Intralesional fat was identified in 12% of the cases. Internal low-signal bands and multilocular appearance were observed in 91%. Cortical expansion was present in 58%. Intramedullary extension was present in all cases, and an entire intramedullary replacement was observed in 33%. Cortical breakage (n = 3) and extraosseous mass formation (n = 1) were observed in cases with pathologic fractures only. A cystic area was observed in one case. Among 21 cases without a pathologic fracture, abnormal signal intensity in the surrounding bone marrow and adjacent soft tissue was observed in 43% and 48%, respectively. All cases exhibited diffuse contrast enhancement. CONCLUSION: Osteofibrous dysplasia exhibited diverse imaging features ranging from lesions confined to the cortex to more aggressive lesions with complete intramedullary involvement or perilesional marrow edema.

Color Doppler Ultrasound of Lower Extremity Varicose Veins: A Simple Grading of Sapheno-Femoral Junction Reflux

PURPOSE: To establish a simple grading method for the severity of an incompetent sapheno-femoral junction (SFJ) using color Doppler ultrasound in patients with lower extremity varicose veins. MATERIALS AND METHODS: 346 legs of 241 consecutive patients with varicose veins were examined (M:F = 96:145, 11-74 years, mean 50 years). The severity of SFJ and sapheno-popliteal (SPJ) incompetence was graded from I to IV according to the patient's position (standing versus supine or prone) and whether the Valsalva's maneuver had been induced. The extent of varicose veins was graded as I to III by the US findings in the SFJ incompetence group. The grading of SFJ incompetence was compared to the extent of varicose vein. RESULTS: SFJ, SPJ, both SFJ and SPJ, and perforator incompetence was observed in 198 (57.2%), 81 (23.4%), 21 (6.1%) and 54 (15.6%), respectively. Among the SFJ incompetence group, severity grade I - IV were observed in 14 (7.1%), 75 (37.9%), 73 (36.9%), and 36 (18.2%), respectively, and the extent grade I - III were noted in 47 (23.7%), 95 (48.0%), and 56 (28.3%), respectively. The SFJ incompetence grade and varicose extent grade showed a positive correlation (p < 0.0001). CONCLUSION: Simple sonographic grading of the severity of SFJ incompetence is possible. The extent of varicose veins in the SFJ incompetence group can be determined using this new grading system.

Changes in Level of the Conus after Corrective Surgery for Scoliosis: MRI-Based Preliminary Study in 31 Patients

BACKGROUND: Detection of postoperative spinal cord level change can provide basic information about the spinal cord status, and electrophysiological studies regarding this point should be conducted in the future. METHODS: To determine the changes in the spinal cord level postoperatively and the possible associated factors, we prospectively studied 31 patients with scoliosis. All the patients underwent correction and posterior fusion using pedicle screws and rods between January 2008 and March 2009. The pre- and postoperative conus medullaris levels were determined by matching the axial magnetic resonance image to the sagittal scout image. The patients were divided according to the change in the postoperative conus medullaris level. The change group was defined as the patients who showed a change of more than one divided section in the vertebral column postoperatively, and the parameters of the change and non-change groups were compared. RESULTS: The mean pre- and postoperative Cobb's angle of the coronal curve was 76.80degrees +/- 17.19degrees and 33.23degrees +/- 14.39degrees, respectively. Eleven of 31 patients showed a lower conus medullaris level postoperatively. There were no differences in the pre- and postoperative magnitude of the coronal curve, lordosis and kyphosis between the groups. However, the postoperative degrees of correction of the coronal curve and lumbar lordosis were higher in the change group. There were also differences in the disease entities between the groups. A higher percentage of patients with Duchene muscular dystrophy had a change in level compared to that of the patients with cerebral palsy (83.3% vs. 45.5%, respectively). CONCLUSIONS: The conus medullaris level changed postoperatively in the patients with severe scoliosis. Overall, the postoperative degree of correction of the coronal curve was higher in the change group than that in the non-change group. The degrees of correction of the coronal curve and lumbar lordosis were related to the spinal cord level change after scoliosis correction.

MR Imaging Findings of Parosteal Lipoma: Case Report

Parosteal lipoma is a rare benign tumor containing mature adipose tissue having an intimate relationship to the periosteum. Characteristically, this tumor presents as a lipomatous mass adjacent to bone, eliciting variable reactive changes in the underlying cortex. We report a case of parosteal lipoma of the foot. The MR findings consisted of juxtacortical lipomatous mass abutting to bony protuberance, with internal fibrous striations, and osseous reaction in the adjacent bone. By the aid of multiplanar imaging capability, high spatial and contrast resolution of MRI, characteristic features of parosteal lipoma can lead to diagnosis on imaging.

Calcific Tendinitis of Flexor Carpi Ulnaris Insertion Site / 대한류마티스학회지

No abstract available.

US Diagnosis of Sparganosis Within the Thigh: Case Report

Sparganosis is an uncommon infection caused by sparganum, a migrating plerocercoid larva. Currently, various imaging modalities have been actively used for the diagnosis of sparganosis before surgery. We present a case of sparganosis arising in the subcutaneous layer of the thigh that was diagnosed only by an ultrasound examination.

The Role of an Axial MR Scan on the Diagnosis of a Meniscal Tear of the Knee Joint

PURPOSE: To evaluate the role of standard axial MR images for the diagnosis of meniscal tears of the knee. MATERIALS AND METHODS: Forty-five patients with a prior MRI examination that underwent arthroscopic surgery of the knee due to clinical impression of a meniscal tear were included in the study group. The sequence for meniscal evaluation was an axial fat-saturated proton density-weighted image with a 4 mm slice thickness. Axial MR images were independently reviewed by two radiologists and were compared with findings of arthroscopy. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the axial MR scan for the diagnosis of the meniscal tear were calculated. RESULTS: A total 90 menisci of 45 patients were evaluated in the axial MR scans. Forty-two patients had meniscal tears, and two of the patients had tears in both menisci; thus, a total of44 meniscal tears were found by arthroscopy. For meniscal tears, the sensitivity of the axial plane was 76.2%, the specificity was 89.1% and the accuracy was 81.1%. False negative meniscal tears were seen in 12 cases and false positive meniscal tears were seen in 5 cases on the axial MR images. CONCLUSION: In standard knee MRI examinations, axial images may be valuable for the detection and localization of meniscal tears.

Tuberculous Spondylitis vs Pyogenic Spondylitis: Focusing on the Discriminative MR Findings for Differentiation

PURPOSE: The purpose of this study is to analyze the most discriminative MR findings for making the differential diagnosis of tuberculous and pyogenic spondylitis. MATERIALS AND METHODS: Sixty MR scans of 18 pyogenic spondylitis patients and 42 tuberculous spondylitis patients were retrospectively reviewed. The statistical analysis was performed using stepwise discriminant analysis and Student's T-test. RESULTS: The patients with tuberculous spondylitis had a significantly higher incidence of MRI findings as follows (p <0.05): smooth margin of a paraspinal mass/abscess in 67% [28/42] of the tuberculous spondylitis patients vs 6% [1/18] in the pyogenic spondylitis patients, mild endplate erosion in 52% [22/42] vs 38% [7/18], respectively, the presence of paraspinal mass/abscess in 100% [42/42] vs 6% [1/18], respectively, central dark signal intensity of the abscess in 86% [36/42] vs 39% [7/18]), respectively, subligamentous spread in 81% [34/42] vs 50% [9/18]), respectively, severe vertebral collapse in 20% [8/42] vs 11% [2/18]), respectively, and posterior extension in 62% [26/42] vs 33% [6/18]), respectively. Among of them, the significant discriminative MR findings were the margin of a paraspinal mass, the grade of endplate erosion and the presence or absence of a paraspinal mass in that order. CONCLUSION: In the differentiation of tuberculous and pyogenic spondylitis, the margin of the paraspinal mass, the grade of endplate erosion and the presence or absence of a paraspinal mass are the most three discriminating MR findings in that order.

Diagnostic Usefulness of Ultrasonographic Examination of Cubital Tunnel Syndrome: Analysis of Ulnar Nerve Cross-sectional Area

PURPOSE: To prospectively evaluate the accuracy of sonography for diagnosis of cubital tunnel syndrome (CUTS) confirmed by electrodiagnostic study. ATERIALS and METHODS: From February 2004 to March 2005, we prospectively analyzed 24 elbows in 19 patients (8 women, 11 men; mean age, 49.2 years; range 23-65 years) with cubital tunnel syndrome, including 5 bilateral cases. Diagnoses of CUTS were confirmed by both clinical symptom and electrodiagnostic study. Sonographic findings of 20 asymptomatic cases served as controls. In sonographic examination, the cross sectional area of the ulnar nerve was measured at the inlet (at the level of medial epicondyle) and outlet (at the level of convergence of flexor carpi ulnaris tendons) of the cubital tunnel. The shape and echogenicity of the ulnar nerve were also evaluated, as were possible causes of entrapment. The accuracy of using ultrasonographic cross sectional area to diagnose CUTS was evaluated with receiver operating characteristic (ROC) analysis. RESULTS: The cross sectional area of the ulnar nerve at the inlet and outlet levels in CUTS patients was increased much more than in the asymptomatic cases. Decreased echogenicity and distortion of normal parallel echotexture of the ulnar nerve were observed in all CUTS patients. At the inlet level, the area under the ROC curve (AUC) was 0.816, and the ideal cut-off value for CUTS diagnosis was 0.08 cm2 with a sensitivity of 58.3%, specificity of 100%, positive predictive value (PPV) of 100%, and negative predictive value (NPV) of 66.7%. At the distal outlet level, the AUC was 0.785, and the cut-off value was 0.06 cm2 with a sensitivity of 79.2%, specificity of 70%, PPV of 76%, and NPV of 73.7%. When the summation value of inlet and outlet cross sectional areas was used, the AUC was 0.853, and cut-off value was 0.14 cm2 with a sensitivity of 70.8%, specificity of 85%, PPV of 85%, and NPV of 70.8%. CONCLUSION: Measurement of the cross sectional area of the ulnar nerve at the inlet and outlet of the cubital tunnel can aid in the sonographic diagnosis of cubital tunnel syndrome by more objectively determining the increase in cross sectional area.

Fibular Hemimelia: A Case Report

Fibular hemimelia is the most common congenital absence or hypoplasia of long bone. In addition to fibular absence or hypoplasia, this entity also includes various combined abnormalities of the lower limbs. We present here three cases of fibular hemimelia who underwent diagnosis and treatment in our hospital. Wee especially focus on the imaging findings of the plain radiographs, and we compare them with the findings found at another presentation.

Development of MRI Phantom for Assessing MR Image Quality

PURPOSE : To evaluate MR image qualities we developed a new MRI phantom with the fixation structures necessary to position it into coil firmly. MATERIALS AND METHODS : We designed MRI phantom for eight evaluation items such as slice thickness accuracy, high contrast spatial resolution, low contrast object detectability, geometry accuracy, slice position accuracy, image intensity uniformity, percent signal ghosting and signal to noise ratio. For the positioning of phantom at coils, the fixation structures were set up on the surface of phantom. Six different MRI units were used for test the possibility for the clinical application and their image qualities were evaluated. RESULTS : We acquired appropriate MR image qualities enough for the evaluation on all used MR units and confirmed that their evaluations were within reliable values compared to real ones for some items. The positioning of our phantom into head coils with fixation structures worked well for proper imaging. CONCLUSION : We found that our prototype of MRI phantom had the possibility of clinical application for MR image quality assessment.

Correlation of Second-look Arthroscopy and MR Findings of Anterior Cruciate Ligament Graft

PURPOSE: To evaluate the postoperative MR findings of the healthy anterior cruciate ligament (ACL) grafts which were confirmed by the second-look arthroscopic examination. MATERIALS AND METHODS: Among 419 cases who underwent the arthroscopic ACL reconstruction by one operator between June 1996 and January 2001, we evaluated 33 MR scans of 29 patients who underwent the postoperative MR scan and the second-look arthroscopic examination (4 patients underwent postoperative MRI twice). There were 18 male and 11 female patients, and the patient 's age ranges from 16 to 59 years-old (mean 29.7). There were 15 cases of autogeneous bone-patellar tendon-bone (BPTB) grafts, 13 cases of autogeneous double-loop hamstring grafts, and 1 case of allogeneous BPTB graft. Thirty-three MRIs were divided into 3 groups according to the time interval between operation and postoperative MR examination: less than 6 months, 7 to 12 months, and more than 13 months. The MR findings of ACL grafts - signal intensity, morphology, continuity, orientation, diameter - were analyzed. RESULTS: The increased signal intensity was found in 29 ACL grafts (87.7%) among 33 MR images. The most common pattern of the graft morphology was a longitudinal streak increased signal band (27 cases, 81.8%). The partial rupture was seen in 9 cases (27.3%), and the lax orientation in 4 cases (12.1%). According to Howell 's scoring system, the signal intensity score of the graft tended to decrease with time after operation, and the sagittal diameter of the graft tended to increase with time after operation. CONCLUSION: The main MR finding of the healthy ACL graft was longitudinal streak increased signal band. The graft signal intensity seemed to decrease, and the sagittal diameter of the graft seemed to increase, as time passes after operation.

Clinical Implication of Magnetic Resonance Imaging in the Idiopathic Inflammatory Myopathies / 대한류마티스학회지

OBJECTIVE: The purpose of the study is to describe the magnetic resonance imaging (MRI) findings and to investigate useful sequences of MRI in inflammatory myopathies. A third goal is to correlate MRI findings with the grade of histopathologic severity. METHODS: Sixteen patients (13 women, 3 men), aged 21-74 years (median age of 49) with inflammatory myositis (examined with both MRI and muscle biopsy) were studied. Ten patients were diagnosed with polymyositis and 6 with dermatomyositis. Conventional T1-weighted (SE 366/12) and T2-weighted (SE 4766/90) fast spin-echo and fat-suppressed T1-weighted MR images with contrast enhancement (FSAT T1 CE) were obtained. Ratios between the signal intensities of a muscle and the signal intensities of subcutaneous fat in the same tomographic sections were calculated to objectively represent the degree of signal intensities. Semi-quantitative grading of severities in muscle biopsy specimen was examined based on invasion of inflammatory cells and necrosis, degeneration and regeneration of muscle fiber by a neuromuscular pathologist. RESULTS: FSAT T1 CE could objectively describe the severity of involvement in inflammatory myopathies. The quadriceps muscle group, especially the vastus muscle tended to be most severely and frequently involved in inflammatory myositis with FSAT T1 CE (statistically insignificant). The vastus intermedius muscle was more severely involved in dermatomyositis than polymyositis. The signal intensity of abnormal muscle sampled by biopsy correlated positively with the grade of muscle biopsy. CONCLUSION: MRI shows promise in identifying pathologic muscle in patients suspected of having one of the inflammatory myopathies. The degree of signal intensity on MRI may reflect the severity of grade in muscle biopsy.

Borrmann Type IV Adenocarcinoma versus Gastric Lymphoma: Spiral CT Evaluation

PURPOSE: To distinguish the spiral CT findings of Borrmann type IV adenocarcinoma from those of gastric lymphoma with diffuse gastric wall thickening. MATERIALS AND METHODS: We retrospectively reviewed the spiral CT scans of 30 patients with Borrmann type IV adenocarcinoma and nine with gastric lymphoma with diffuse gastric wall thickening. In all patients the respective condition was pathologically confirmed by gastrectomy. CT scanning was performed after peroral administration of 500-700ml of water. A total of 120-140ml bolus of nonionic contrast material was administered intravenously at a flow rate of 3ml/sec and two-phase images were obtained at 35-45 sec(early phase) and 180 sec(delayed phase) after the start of bolus injection. Spiral CT was performed with 10mm collimation, 10mm/sec table feed and 10mm reconstruction. We evaluated the degree and homogeneity of enhancement of thickened entire gastric wall, and the enhancement pattern of gastric inner layer, as seen on earlyphase CT scans. On early and delayed views, the thickness of gastric wall and the presence of perigastric fat infiltration were determined. The enhancement patterns of gastric inner layer were classified as either continuous or discontinuous thick enhancement, thin enhancement, or nonenhancement. RESULTS: The thickness of gastric wall was 1.2-3.5cm(mean 2.2cm) in cases of adenocarcinoma and 1.2-7.6c m (mean 4cm) in lymphoma. Perigastric fat infiltration was seen in 24 patients with adenocarcinoma(80 %) and four with lymphoma(44%). In those with adenocarcinoma, the degree of enhancement of entire gastric wall was hyperdense in fifteen patients(50%) and isointense in eleven (37 %). Seven patients with lymphoma(78 % ) showed hypodensity. In those with adenocarcinoma, continuous thick enhancement of gastric inner layer was seen in 18 patients(60 %) and discontinuous thick enhancement in nine(30%). In lymphoma cases, no thick enhancement was observed. Thin enhancement of gastric inner layer was demonstrated in three patients with adenocarcinoma( 10 %) and two with lymphoma(22 %). In seven patients with lymphoma(78 %), there was no enhancement. CONCLUSION: The following early-phase findings are highly suggestive of gastric lymphoma: a gastric wall thickness of more than 3 cm; no or minimal perigastric fat infiltration, hypodense enhancement of thickened entire gastric wall; and no or thin enhancement of gastric inner layer.