Adhesive Capsulitis of the Shoulder: MR Arthrography

PURPOSE: Adhesive capsulitis is a clinical syndrome involving pain and decreased joint motion caused by thickening and contraction of the joint capsule. The purpose of this study is to describe the MR arthrographic findings of this syndrome. MATERIALS AND METHODS: Twenty-nine sets of MR arthrographic images were included in the study. Fourteen patients had adhesive capsulitis diagnosed by physical examination and arthrography, and their MR arthrographic findings were compared with those of 15 subjects in the control group. The images were retrospectively reviewed with specific attention to the thickness of the joint capsule, volume of the axillary pouch (length, width, height(depth)), thickness of the coracohumeral ligament, presence of extra-articular contrast extravasation, and contrast filling of the subcoracoid bursa. RESULTS: Mean capsular thickness measured at the inferior portion of the axillary pouch was 4.1 mm in patients with adhesive capsulitis and 1.5 mm in the control group. The mean width of the axillary pouch was 2.5 mm in patients and 9.5 mm in controls. In patients, the capsule was significantly thicker and the axillary pouch significantly narrower than in controls (p<0.05). Capsule thickness greater than 2.5 mm at the inferior portion of the axillary pouch (sensitivity 93%, specificity 80%) and a pouch narrower than 3.5 mm (sensitivity 93%, specificity 100%) were useful criteria for the diagnosis of adhesive capsulitis. In patients with this condition, extra-articular contrast extravasation was noted in six patients (43%) and contrast filling of the subcoracoid bursa in three (21%). CONCLUSION: The MR arthrographic findings of adhesive capsulitis are capsular thickening, a low-volume axillary pouch, extra-articular contrast extravasation, and contrast filling of the subcoracoid bursa. Capsule thickness greater than 2.5 mm at the inferior portion of the axillary pouch and a pouch width of less than 3.5 mm are useful diagnostic imaging characteristics.

Prediction of Parent Artery of Anterior Communicating Artery Aneurysm on CT Angiography

PURPOSE: To determine whether CT angiography can predict the parent artery of an anterior communicating aneurysm on the basis of characteristics of the aneurysm and precommunicating anterior cerebral artery. MATERIALS AND METHODS: Eighteen patients with anterior communicating aneurysm were studied prospectively using CT angiography and conventional angiography. The parent artery of an aneurysm was predicted by evaluating aneurysm neck location, direction of aneurysm projection, and size of the precommunicating anterior cerebral artery, as seen on CT angiography. A somatom Plus-4 spiral CT scanner was used and shaded-surface display three-dimensional images were constructed. RESULTS: Aneurysm neck was located near the parent artery in 12 cases(66.7%), and aneurysm projection was against the parent artery in 11 cases(61.1 %). The parent artery of the anterior cerebral artery was larger in 15 cases (8 3 .3 %), including ten cases of hypoplasia or agenesis of the contralateral anterior cerebral artery. In 17 of 18 aneurysms(94.4%) the parent artery seen on DSA was correctly predicted by CT angiography. CONCLUSION: Teh parent artery of an anterior communicating aneurysm can be predicted by evaluating a-neurysm neck location, direction of aneurysm projection, and precommunicating anterior cerebral artery, as seen on CT angiography.

Intracranial Inflammatory Pseudotumors: MRI and CT Findings

PURPOSE: The purpose of this study was to describe the MR imaging and CT findings of intracranial inflammatory pseudotumors. MATERIALS AND METHODS: We reviewed the MR imaging (n=8) and CT (n=4) studies of eight patients (M:F = 4:4, mean age: 41 years) with pathologically proven intracranial inflammatory pseudotumor. The findings were then evaluated with regard to location, shape, MR signal intensity, CT density and degree of contrast enhancement of the lesion, surrounding parenchymal edema, adjacent bone change and the location of accompanying extracranial lesion. RESULTS: In two patients, the parietal convexity was involved unilaterally, with no extracranial mass, and in the other six, the middle cranial fossa was involved unilaterally and extracranial mass was present. The lesion also involved the tentorium in four cases, the cavernous sinus in four, the anterior cranial fossa in one, and the posterior cranial fossa in one. The location of extracranial mass was the mastoid and middle ear cavity in two cases, the infratemporal fossa in two, both the infratemporal fossa and paranasal sinuses in one, and the orbit in one. MR images showed diffuse dural thickening in all eight cases, leptomeningeal thickening in four, and focal meningeal-based mass in two. As seen on T1-weighted images, the lesions were isointense to gray matter in eight cases, and on T2-weighted images were hypointense in seven cases and isointense in one. Marked homogeneous contrast enhancement was seen in all eight cases. The lesions seen on brain CT, performed in two cases, were isodense. Adjacent brain parenchymal edema and the destruction of adjacent bones were each seen in five cases. CONCLUSION: The characteristic MR findings of intracranial inflammatory pseudotumors are(1) diffuse dural thickening;(2) a focal meningeal-based mass which on T2-weighted images is seen as hypointense; and marked (3) contrast enhancement : these findings are, however, nonspecific. In order to differentiate these tumors, an awareness of these findings is, however, useful.

Imaging Features of Rhabdoid Tumor of the Kidney in Children

PURPOSE: To evaluate the difference in radiologic features of rhabdoid tumor of the kidney (RTK) in children according to the location of the tumor within the kidney. MATERIALS AND METHODS: We retrospectively reviewed the radiologic findings of pathologically confirmed RTK in seven children (5 boys and 2 girls; age range, 6 months to 4 years 8 months; median, 18 months). All subjects underwent abdominal CT. We analyzed tumor location, size, and margin; renal hilar involvement, subcapsular hematoma, calcification, necrosis, and lymphadenopathy. RTK was classified according to the location of the tumor within the kidney: A tumor that mainly located in the central portion of the kidney with or without peripheral extension was described as type I, while one located at the periphery was type II. Imaging findings between the two types were compared. RESULTS: Tumor size varied from 3 cm to 12 cm. Tumor outlines were ill-defined in four cases but relatively well-defined in three. Four tumors (57 %) were type I. Hilar involvement was found in all four and a small subcapsular hematoma in one. Three tumors (43%) were type II, and in all three, large crescent-shaped subcapsular hematomas were found. CONCLUSION: Centrally located RTK showed hilar involvement with a small subcapsular hematoma, while in cases of peripherally located RTK, a large subcapsular hematoma was present. These findings may be helpful for the differential diagnosis of other pediatric renal tumors.

Imaging Features of Rhabdoid Tumor of the Kidney in Children

PURPOSE: To evaluate the difference in radiologic features of rhabdoid tumor of the kidney (RTK) in children according to the location of the tumor within the kidney. MATERIALS AND METHODS: We retrospectively reviewed the radiologic findings of pathologically confirmed RTK in seven children (5 boys and 2 girls; age range, 6 months to 4 years 8 months; median, 18 months). All subjects underwent abdominal CT. We analyzed tumor location, size, and margin; renal hilar involvement, subcapsular hematoma, calcification, necrosis, and lymphadenopathy. RTK was classified according to the location of the tumor within the kidney: A tumor that mainly located in the central portion of the kidney with or without peripheral extension was described as type I, while one located at the periphery was type II. Imaging findings between the two types were compared. RESULTS: Tumor size varied from 3 cm to 12 cm. Tumor outlines were ill-defined in four cases but relatively well-defined in three. Four tumors (57 %) were type I. Hilar involvement was found in all four and a small subcapsular hematoma in one. Three tumors (43%) were type II, and in all three, large crescent-shaped subcapsular hematomas were found. CONCLUSION: Centrally located RTK showed hilar involvement with a small subcapsular hematoma, while in cases of peripherally located RTK, a large subcapsular hematoma was present. These findings may be helpful for the differential diagnosis of other pediatric renal tumors.

The Usefulness of Postoperative Pinhole Bone Scintigraphy in the Assessment of Prognosis after Multiple Drilling or Vascularized Bone Graft in Patients with Avascular Necrosis of Femoral Head / 대한핵의학회잡지

PURPOSE:It is important to evaluate the healing process of avascular necrosis (AVN) involving femoral head after treatment. The purpose of this study was to assess the usefulness of pinhole bone scintigraphy in the AVN of femoral head after surgery. MATERIALS AND METHODS: We analyzed the changing pattern of pinhole bone scintigram in 21 femoral heads of 16 patients (14 lesions/11 male, 7 lesions/5 female, mean age: 39.4 yrs) before and after multiple drilling or vascularized bone grafting for AVN of the femoral head. In all patients, pre-operative scintigrams were obtained at 1 to 3 months before treatment and the first post-operative scintigrams were obtained at 1 to 3 months after treatment. All patients were followed for 2 to 4 years after operation. RESULTS: The findings of the pinhole scintigrams were divided into three patterns: 1) curvilinear, 2) scattered spotty and 3) undetermined. The 10 of 11 lesions with curvilinear pattern had good postoperative clinical and radiological follow-up findings. However, all 6 lesions with scattered spotty pattern showed poor postoperative findings, which necessitated total hip joint replacement. Of the 4 lesions with undetermined pattern, 2 required total hip joint replacement. There was significant difference in postoperative prognosis between the curvilinear and scattered spotty patterns (p<0.05). CONCLUSION: We conclude that the pattern of pinhole bone scintigram obtained within 1 to 3 months after multiple drilling or vascularized bone graft operation is a useful prognostic indicator in the AVN of femoral head.

Usefulness of Turbo Spin-Echo MR Imaging in Meniscal Tears of the Knee

PURPOSE: To evaluate the usefulness and diagnostic accuracy of turbo spin-echo(TSE) proton-density andT2-weighted images of meniscal tears of the knee. MATERIALS AND METHODS: We retrospectively evaluated thesensitivity, specificity, and accuracy of TSE proton density and T2-weighted images of meniscal tears confirmedarthroscopically or surgically in 47 patients(98 menisci). The routine TSE parameters used in all patients werethe dual echo sequence with sagittal proton density and T2-weighed images(4000/16, 90/5/2 [TR/effectiveTE/ETL/NEX]), and fat-suppressed coronal proton density and T2-weighted images. The chi-square test was used forstatistical analysis. RESULTS: The sensitivity, specificity, and accuracy of TSE proton density images for thedetection of meniscal tears were 93.9%, 93.8%, and 93.9%, respectively, in the medial meniscus, and 92.9%, 91.4%,and 91.8% in the lateral. On T2-weighted images the corresponding figures were 87.9%, 93.8%, and 89.8%,respectively, in the medial meniscus, and 64.3%, 91.4%, and 83.7 % in the lateral. CONCLUSION: With regard tosensitivity and accuracy, TSE proton density images of meniscal tears were superior to TSE T2-weighted images.

MR Imaging of the Combined Anterior and Posterior Cruciate Ligament Tears: Focussing on the Patterns of Injuries and Associated Findings

PURPOSE: To evaluate the patterns of injuries and frequency of associated findings on MR imaging in patients with both anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) tears; to compare the associated findings, as seen on MR imaging, in cases with both ACL and PCL tears with those with ACL or PCL tears. MATERIALS AND METHODS: Ten patients with combined ACL and PCL tears, 16 with ACL tears and 18 with PCL tears, all confirmed by arthroscopy or open surgery, were involved in this study. To identify the associated knee injuries, MR images were retrospectively evaluated. RESULTS: In ten patients with combined ACL and PCL tears, open surgery led to the identification of six complete ACL tears (60%), four partial ACL tears (40%), eight complete PCL tears (80%) and two partial PCL tears (20%). Injuries associated with these combined tears, and revealed by MR imaging, comprised six medial collateral ligament injuries (60%), six lateral collateral ligament injuries (60%), five medial meniscal injuries (50%), three lateral meniscal injuries (30%), nine bony injuries (90%), two posterior capsular injuries (20%), and three popliteus muscle injuries (30%). The frequency of popliteus muscle injury was significantly different (p<0.05, Fisher's exact test) between the group with both ACL and PCL tears and that with ACL or PCL tears. CONCLUSION: Associated findings in patients with combined ACL and PCL tears are more frequentthan in those with ACL or PCL tears. In cases involving combined ACL and PCL tears, associated findings-as seen on MR images-should thus be carefully examined.