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Aim: To assess the efficacy of three-dimensional (3D) volumetric interpolated breath-hold examination (VIBE) magnetic resonance imaging (MRI) with Dixon quantification for differentiating clear-cell from non-clear-cell types of renal cell carcinoma (RCC)., Materials and Methods: The 3D VIBE Dixon renal MRI examinations of 44 patients with 45 histologically confirmed RCCs was analysed. The fat fractions and signal intensity indexes (SI index ) of the solid portions of clear-cell and non-clear-cell RCCs were measured and compared using Student's t-test and receiver operating characteristic (ROC) curves. The agreement of measurements among observers was evaluated by the intraclass correlation coefficient (ICC), and Bland-Altman plots., Results: The mean values of fat fraction (13.16±7.16%) and SI index (22.64±15.7%) in clear-cell RCCs were significantly higher than that in non-clear-cell RCCs (7.7±2% and 7.9±4.8%; p<0.001, respectively). With the area under the ROC curve (AUC) of the fat fraction at 0.811, 75% (95% CI: 55.1-89.43%) sensitivity and 76.5% (95% CI: 50.1-93.2%) specificity for diagnosing clear-cell RCC were obtained at a cut-off fat fraction value of 8.9%. With a cut-off value of 8.89%, the diagnostic sensitivity and specificity were 85.7% (95% CI: 67.3-96%) and 70.6% (95% CI: 44-89.7%), respectively. The AUC of the SI index was 0.870 (0.766-0.973). ICC and Bland-Altman plots show excellent agreement of the tumour fat fraction and SI index measurement between the two observers., Conclusion: Intracellular lipid content analysis using the 3D Dixon technique can help to differentiate clear-cell from non-clear-cell RCCs., (Copyright © 2018 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Background Neoadjuvant chemotherapy has made limb-salvage surgery possible for the patients with osteosarcoma. Diffusion-weighted magnetic resonance imaging (DWI) has been used to monitor chemotherapy response. Purpose To correlate the apparent diffusion coefficient (ADC) values with histopathology subtypes of osteosarcoma after neoadjuvant chemotherapy. Material and Methods Twelve patients with osteoblastic (n = 7), chondroblastic (n = 4), and fibroblastic (n = 1) osteosarcomas underwent post-chemotherapy DWI before limb-salvage surgery. ADCs corresponding to 127 histological tissue samples from the 12 resected specimens were compared to histological features. Results The mean ADC value of non-cartilaginous viable tumor (38/91, ADC = 1.22 ± 0.03 × 10 -3  mm 2 /s) was significantly ( P < 0.001) lower than that of non-cartilaginous tumor cell necrosis without stroma disintegration (25/91, ADC =1.77 ± 0.03 × 10 -3  mm 2 /s), cartilaginous viable tumor (14/91, ADC = 2.19 ± 0.04 × 10 -3  mm 2 /s), and cystic areas including liquefied necrosis, blood space, and secondary aneurysmal bone cyst (14/91, ADC = 2.29 ± 0.05 × 10 -3  mm 2 /s). The mean ADC value of non-cartilaginous tumor cell necrosis was also significantly ( P < 0.001) smaller than those of viable cartilaginous tumor and cystic/hemorrhagic necrosis whereas the mean ADC values were not significantly ( P > 0.05) different between viable cartilaginous tumor and cystic/hemorrhagic necrosis. Conclusion DWI allows assessment of tumor necrosis after neoadjuvant chemotherapy by ADC differences between viable tumor and necrosis in fibroblastic and osteoblastic osteosarcomas whereas viable chondroblastic osteosarcoma has high ADC and cannot be distinguished reliably from necrosis.

Objective: The purpose of this study was to compare the efficacy of submucosal enhancement on dynamic contrast-enhanced MRI (DCE-MRI) and detection of a stalk on DWI for differentiating stage T1 from stage T2 bladder urothelial carcinoma., Subjects and Methods: Our prospective study was approved by the institutional medical ethics committee and informed consent was obtained from all patients. Fifty-nine patients (92 tumors in total) with urothelial bladder cancer underwent MRI within 2 weeks before surgery. Two image sets of T2-weighted MRI with DWI and T2-weighted with DCE-MRI were interpreted independently at 2-week intervals by two uroradiologists without any knowledge of the surgical or histologic findings. The tumor was categorized as stage T1 or lower when a stalk was evident at the tumor base on DWI or when continuous linear submucosal enhancement was detected in the early phase of DCE-MRI. Tumors without stalks or with discontinuous linear submucosal enhancement were categorized as stage T2., Results: Of the 42 tumors with stalks on DWI, 41 showed continuous and one had discontinuous submucosal enhancement on DCE-MRI. In 50 carcinomas without stalks on DWI, submucosal enhancement was absent in 34, continuous in 12, and discontinuous in four. The staging accuracy of DWI (91.3%, 84/92) and DCE-MRI (91.3%, 84/92) was improved to 94.6% (87/92) by combining the interpretations of both DWI and DCE-MRI., Conclusion: Submucosal linear enhancement under the tumor base on DCE-MRI complements tumor stalk detection on DWI for differentiating stage T1 from stage T2 bladder urothelial carcinoma.

Aim: To assess the efficacy of diffusion-weighted (DWI) magnetic resonance imaging (MRI) in distinguishing cystitis glandularis (CG) from bladder urothelial carcinoma., Materials and Methods: Ultrasound, computed tomography (CT), conventional MRI, and DWI of 30 patients with histopathologically confirmed CG were analysed retrospectively and the imaging findings were correlated to the findings at histology., Results: Ultrasound was non diagnostic in 11/18 and misdiagnosed malignancy in 7/18; CT was non diagnostic in 6/10 and misdiagnosed malignancy in 4/10; MRI was non diagnostic in 0 and misdiagnosed malignancy in 4/5 respectively. One patient with diffuse bladder wall thickening was correctly diagnosed as CG at MRI. All six patients who underwent additional DWI were accurately diagnosed as having CG with no or minimal reduction of diffusion., Conclusions: Diffusion is not reduced or shows minimal reduction in CG. DWI may aid the differential diagnosis of CG., (Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

To assess the diagnostic efficacy of diffusion-weighted MR imaging (DWI) for evaluating inflammatory activity in patients with Crohn's disease (CD). A total of 47 CD patients underwent MR enterography (MRE) and DWI using 3 b values of 50, 400, and 800 s/mm. Apparent diffusion coefficients (ADCs) of inflamed and normal bowel wall were calculated. The conventional MRE findings and DWI signal intensities were qualitatively scored from 0 to 3. The correlation between Crohn disease activity index (CDAI) and both ADCs and magnetic resonance imaging scores was analyzed. Receiver-operating characteristic curve analysis was used to determine the diagnostic accuracy of CD activity. Of the 47 patients, 25 were active CD (CDAI≥150) and 22 were inactive (CDAI<150). Diffusion-weighted MR imaging and MRE + DWI scores of active CD were significantly higher than that of inactive CD (both P < 0.001). Apparent diffusion coefficients in inflamed segments of active CD were lower than that of inactive CD (P < 0.001). The DWI scores (r = 0.74, P < 0.001), ADCs (r = -0.71, P < 0.001), MRE scores (r = 0.54, P < 0.001), and MRE + DWI scores (r = 0.66, P < 0.001) were all correlated with CDAI. The areas under the receiver-operating characteristics curves for ADCs, DWI scores, MRE scores, and MRE + DWI scores ranged from 0.83 to 0.98. The threshold ADC value of 1.17 × 10 mm/s allowed differentiation of active from inactive CD with 100% sensitivity and 88% specificity. Diffusion-weighted MR imaging and ADC correlated with CD activity, and had excellent diagnostic accuracy for differentiating active from inactive CD.

OBJECTIVE. The purpose of this study was to determine an optimal multiparametric MRI protocol for characterizing tumors of low versus high grade and differentiating tumors as T1 versus T2 for preoperative staging of bladder urothelial carcinoma. SUBJECTS AND METHODS. Thirty-nine patients underwent MRI within 1 week before surgery. Three image sets-T2-weighted plus diffusion-weighted MRI (DWI), T2-weighted plus dynamic contrast-enhanced MRI (DCE-MRI), and T2-weighted plus DCEMRI plus DWI-were independently interpreted by two readers at 2-week intervals. ROC curves were plotted for both readers to compare the diagnostic efficacy of the three sets for detrusor muscle invasion for each reader, and the areas under the ROC curve were compared by use of the Bonferroni test. The apparent diffusion coefficient (ADC) values were correlated with histopathologic grade. RESULTS. A total of 49 category T1 and T2 lesions were analyzed. The average ADC of 11 low-grade tumors (1.141 ± 0.164 × 10(-3) mm(2)/s) was significantly (p < 0.05) higher than that of 20 high-grade malignant tumors (0.766 ± 0.091 × 10(-3) mm(2)/s). Neither reader considered T1 tumors as probably having muscle invasion (category T2) in the T2-weighted plus DWI image sets or the T2-weighted plus DWI plus DCE-MRI image sets. Using the T2-weighted plus DCE-MRI sets, the two readers overstaged 13 and 15 of 36 tumors by misdiagnosing category T1 as T2. With the cutoff ADC value of 0.899 × 10-3 mm(2)/s, the sensitivity and specificity for differentiating high- and low-grade bladder urothelial carcinoma were 100% and 95%. CONCLUSION. Multiparametric MRI with T2-weighted plus DWI plus DCE technique is the optimal protocol for preoperative staging of organ-confined bladder urothelial carcinoma. The ADC of low-grade tumors is significantly higher than that of high-grade tumors with 100% sensitivity and 95% specificity at a cutoff ADC value of 0.899 mm(2)/s.

Purpose: To assess the feasibility of diffusion tensor imaging (DTI) of normal kidneys and the influence of hydration state., Materials and Methods: Ten healthy volunteers underwent renal DTI after fasting for 12 hours and 4 hours, without fasting, and following water diuresis. Medullary and cortical apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were measured and compared in the four different states of hydration. DTI was performed with a 3T magnetic resonance imaging (MRI) system using fat-saturated single-shot spin-echo echo planar imaging sequence., Results: ADC of normal cortex (2.387 ± 0.081 × 10(-3) mm(2) /s) was significantly higher (t = 20.126, P = 0) than that of medulla (1.990 ± 0.063 × 10(-3) mm(2) /s). The FA value of normal cortex (0.282 ± 0.017) was significantly lower (t = -42.713, P = 0) than that of medulla (0.447 ± 0.022). The ADC and FA values of the left renal cortex (2.404 ± 0.082 × 10(-3) mm(2) /s, 0.282 ± 0.017) and medulla (2.002 ± 0.081 × 10(-3) mm(2) /s, 0.452 ± 0.024) were not significantly different (P > 0.05) from those of right renal cortex (2.369 ± 0.080 × 10(-3) mm(2) /s, 0.283 ± 0.018) and medulla (1.978 ± 0.039 × 10(-3) mm(2) /s, 0.443 ± 0.019). Values for ADC (×10(-3) mm(2) /s) and FA in the 12-hour fasting, 4-hour fasting, nonfasting, and water diuresis states were 2.372 ± 0.095 and 0.278 ± 0.018, 2.387 ± 0.081 and 0.282 ± 0.017, 2.416 ± 0.051 and 0.279 ± 0.023, 2.421 ± 0.068, and 0.270 ± 0.021, respectively, in cortex, 1.972 ± 0.084 and 0.438 ± 0.014, 1.990 ± 0.063 and 0.447 ± 0.022, 2.021 ± 0.081 and 0.450 ± 0.031, 2.016 ± 0.076 and 0.449 ± 0.028, respectively, in medulla. The ADC and FA values in different hydration states were not significantly different (P > 0.05)., Conclusion: DTI of normal kidneys is feasible with reproducible ADC and FA values independent of hydration states., (© 2013 Wiley Periodicals, Inc.)

Objective: To investigate the relationship of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values with renal function on 3T diffusion tensor imaging (DTI) in chronic kidney disease., Materials and Methods: Twenty healthy volunteers and 29 patients with CKD underwent DTI. The relationship among ADC, FA, and renal function was analyzed., Results: Cortical and medullary ADC and FA values of patients with chronic kidney disease were lower than those of healthy volunteers (P = 0.000). Both the renal ADC and FA values correlated inversely with serum creatinine and blood urea nitrogen (P < 0.05)., Conclusion: DTI is a feasible and non-invasive means to reflect the severity of renal function damaged.

Aim: To compare the efficacy of apparent diffusion coefficient (ADC) and normalized ADC (nADC) for estimating the histological grade of vesical urothelial carcinoma and to identify an optimal reference for nADC calculation., Materials and Methods: Thirty patients with histologically confirmed vesical urothelial carcinomas underwent preoperative diffusion-weighted magnetic resonance imaging (DW-MRI) of the pelvis. nADC of the tumour was calculated as ADC (tumour)/ADC (reference) using urine in the bladder lumen, and the obturator internus and gluteus maximus muscles as reference. Receiver operating characteristic (ROC) curves were constructed and compared to identify an optimal reference for nADC calculation., Results: Both ADC and nADC of low-grade tumours (1.112 ± 0.159 × 10(-3) mm(2)/s, 0.403 ± 0.047 × 10(-3) mm(2)/s) were significantly (p < 0.001) higher than those of high-grade tumours (0.772 ± 0.091 × 10(-3) mm(2)/s, 0.276 ± 0.033 × 10(-3) mm(2)/s). The area under the nADC ROC curve using urine as reference was significantly (p = 0.000) larger (0.995) than those using obturator internus (0.960) and gluteus maximus (0.945)., Conclusions: nADC is superior to ADC for estimating the histological grade of bladder carcinoma using urine in the bladder lumen as an optimal reference for nADC calculation., (Copyright © 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Purpose: To investigate the efficacy of diffusion-weighted MRI (DWI) in differentiating recurrent tumor from chronic inflammation and fibrosis after cystectomy or transurethral resection of bladder cancer., Methods: Eleven patients with suspected tumor recurrence underwent pelvic DWI and dynamic contrast-enhanced (DCE) MRI at 3 months to 7 years following bladder cancer resection. The diagnosis was histologically confirmed in all patients by transurethral or cystoscopic resection of 27 lesions within 2 weeks of MR examinations., Results: The accuracies, sensitivities, specificities, and positive predict values of DWI (92.6%, 100%, 81.8%, and 88.9%) were higher than those of DCE MRI (59.3%, 81.3%, 27.3%, and 54.2%) for detecting recurrent tumors. Using receiver operating characteristic analysis, the accuracy of DWI was significantly higher than that of DCE MRI (P < 0.05). There was no significant difference between DWI diagnosis and histopathology (P > 0.05), whereas the difference between diagnosis of DCE MRI and histopathology was significant (P < 0.05). The normalized apparent diffusion coefficients of recurrent tumors (0.697 ± 0.219) were significantly (P < 0.05) lower than those of postoperative inflammation or fibrosis (1.019 ± 0.143)., Conclusions: DWI is superior to DCE MRI for differentiating recurrent bladder tumors from postoperative inflammation or fibrosis. DWI can be included in the follow-up MRI protocol after bladder cancer surgery.

Cryptococcus neoformans and Candida are common opportunistic pathogens of human. There is very limited literature on Cryptococcus neoformans cholangitis or Candida cholangitis in immunocompetent patient while mixed Cryptococcus neoformans and Candida cholangitis has not been reported in the literature ever before. We hereby report the imaging findings of a case of mixed Cryptococcus neoformans and Candida cholangitis in an immunocompetent boy. The CT features included nodules in the cystic duct and common bile duct, dilatation of the intra- and extrahepatic bile ducts with mural thickening, irregular hypodense mass-like lesion extending along the bile ducts from the liver hilum to the periphery which was confirmed by the presence of enlarged and confluent lymph nodes. CT characteristics can contribute to timely diagnosis and treatment of this disease.

Objective: The objective of this study was to assess the efficacy and clinical value of 64-slice computed tomography angiography (CTA) with image fusion for demonstrating the perigastric venous anatomy., Methods: Twenty-six patients with gastric cancer underwent abdominal CTA examinations. Computed tomography angiography of stomach and perigastric veins and arteries were reconstructed and fused using volume-rendering technique. The inflow and courses of perigastric veins as well as the spatial relationship among the perigastric veins, arteries, and stomach were compared with surgery., Results: Compared with surgical findings, the visualization rate of the 7 perigastric veins on CTA was 90.9% to 100%. There was a statistically significant decrease in number of short gastric veins identified on CTA compared with surgery (P = 0.004). There was no statistically significant difference between the 2 modalities in detecting other perigastric veins including the left gastric vein, right gastric vein, right gastroepiploic vein, left gastroepiploic vein, posterior gastric vein, and gastrocolic trunk (P = 0.317, P = 0.157, P = 1, P = 1, P = 0.317, P = 1, respectively)., Conclusions: Sixty-four-slice CTA with image fusion clearly depicts most of perigastric veins and their relationship with the stomach and perigastric arteries. It can facilitate gastrectomy.

Objective: To evaluate the efficacy of discriminant function analysis of perirectal tumor infiltration with dynamic contrast-enhanced 64-detector row CT in rectal cancer., Materials and Methods: Forty-nine patients with rectal cancer underwent dynamic contrast-enhanced CT. A total of 96 axial CT slices containing the tumors were evaluated. The 96 images were separated into two groups with or without perirectal tumor infiltration based on pathological findings. The discriminant function was set-up using CT density differences between the mass and the adjacent perirectal tissue within 5 mm from the mass at 20 and 40 s as independent variables. The results of the discriminant function analysis were compared to those of CT morphology and pathology., Results: CT morphological diagnosis was accurate on 71.9% (69/96) of the slices with 82.5% sensitivity and 64.3% specificity. Discriminant function analysis correctly identified 88.5% (85/96) of the slices with 85.0% sensitivity and 91.1% specificity. Overstaging occurred significantly more (P<0.05) on morphological analysis (20.8%, 20/96) than discriminant function analysis (5.2%, 5/96) of the CT slices., Conclusions: Discriminant function analysis of dynamic contrast-enhanced CT improves the diagnostic accuracy and specificity of perirectal tumor infiltration in rectal cancer., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

Objective: Pulmonary Kaposi's sarcoma (KS) occurs in more than 10% of patients with acquired immunodeficiency syndrome (AIDS) and has a high mortality rate. Prompt detection, diagnosis, and treatment reduce patient morbidity and mortality. The objective of this study was to determine the efficacy of 99mTc-hexakis-2-methoxy isobutyl isonitrile (99mTc-MIBI) imaging in detecting pulmonary AIDS-related KS., Methods: 99mTc-MIBI imaging was performed on 72 human immunodeficiency virus-seropositive patients with bronchoscopic diagnosis of pulmonary KS (36 patients), pneumonia (22), normal tracheo-bronchial tree (11), lymphoma (2), and bronchogenic carcinoma (1). Lung uptake and lymph node detection in KS were compared on planar and single photon emission computed tomography (SPECT) scans., Results: The lung/myocardium ratios on the 1-h planar images were significantly higher in KS and normal lungs than opportunistic infection. Using the lung/myocardium ratio of 1 as cutoff, the sensitivity, specificity, and accuracy of the 1-h planar images for detecting pulmonary KS were 75, 57.58, and 66.67%, respectively. Abnormal lymph node uptake, pleural/pericardial effusions, and ascites were detected more readily on SPECT., Conclusion: Planar 99mTc-MIBI imaging has moderate sensitivity, specificity, and accuracy for detecting pulmonary KS. SPECT is more effective in detecting abnormal lymph nodes, pleural/pericardial effusions, and ascites. 99mTc-MIBI SPECT followed by planar imaging at 40-60 min can be useful in assessing pulmonary KS.

Background: Tuberculosis (TB) of the parotid gland is rare, even in endemic regions. Approximately 100 cases have been reported in the English literature. The computed tomographic (CT) features, however, have seldom been studied., Purpose: To determine the diagnostic CT features of tuberculosis of the parotid gland., Material and Methods: CT studies of four histologically proven cases of tuberculosis of the parotid gland were retrospectively reviewed., Results: A total of 15 enlarged lymph nodes were found in the superficial lobes of the parotid glands. The nodes were arranged linearly within the gland. Enhancement patterns included homogeneous enhancement (9/15, 60%), homogeneous enhancement with eccentric microcysts (3/15, 20%), and thick-walled rim enhancement with central lucency (3/15, 20%). Thickened adjacent fascial plane and platysma were seen in two patients. Ipsilateral cervical lymphadenopathy was seen in all patients., Conclusion: In patients presenting with unilateral parotid nodules, TB should be considered when linearly arranged enhancing nodules are demonstrated in the superficial lobes of the glands on CT scan.

Background: Kapoksi's sarcoma (KS) is a common neoplasm complicating acquired immunodeficiency syndrome (AIDS). Skin, mucus membranes, lymph nodes, gastrointestinal tract and lungs may be involved. Kaposi's sarcoma has been demonstrated by scintigraphy, and a (99m)Tc-hexakis-2-methoxy isobutyl isonitrile (MIBI) scan can demonstrate lymphoma and tumors of the brain, nasopharynx, thyroid, parathyroid, lung, breast and kidney. It may also be useful for detecting and delineating the extent of KS. The objective of this study was to determine the efficacy of (99m)Tc-MIBI scanning to demonstrate cutaneous AIDS-associated KS, lymphedema and lymphadenopathy in the extremities., Methods: Whole body (99m)Tc-MIBI scans were obtained on 40 patients with AIDS-associated KS. Abnormal uptake of (99m)Tc-MIBI in the skin, subcutaneous soft tissues and lymph nodes was compared with the clinical assessment., Results: The (99m)Tc-MIBI uptake was noted in the cutaneous/subcutaneous KS of the extremities with a sensitivity of 73.53%, a specificity of 96.91% and an accuracy of 91.31%. Abnormal lymph nodes and lymphedema were detected in more patients on (99m)Tc-MIBI scans (33 and 18 patients) than clinical assessment (10 and 12 patients), respectively. Lymphedema of the lower extremity was found in four of 17 patients without any palpable or abnormal lymph node uptake of (99m)Tc-MIBI in the inguinal regions. Follow-up (99m)Tc-MIBI scans after treatment showed no uptake in the skin lesions and decreased uptake in the lymph nodes corresponding to complete clearing on clinical assessment., Conclusions: (99m)Tc-MIBI imaging provides additional information on the extent of lymph node involvement and more precise staging and therapeutic planning. It may be useful as a predictive test or follow up of response of cutaneous KS to treatment.

The purpose of this study was to determine the efficacy of diffusion-weighted imaging (DWI) and magnetization transfer imaging (MTI) in the differential diagnosis of brain infarct, infection, hamartoma, and tumor in 106 children. The apparent diffusion coefficients (ADCs) and magnetization transfer ratios (MTRs) of the lesions were compared using nonparametric tests. There was an inverse relationship between ADC and MTR in subacute/chronic infarct, infection, hamartoma, arachnoid cyst, and tumor relative to normal brain parenchyma. Both ADC and MTR were reduced in acute infarct. DWI and MTI had a complementary role in the differential diagnosis of acute infarct from infection with lower MTR, from hamartoma with higher ADC, and from low-grade gliomas and benign tumors that had higher ADCs and lower MTRs. ADCs increased and MTRs decreased with the duration of infarct and lower tumor grade.

Background and Purpose: Pyogenic and tuberculous spondylitis can mimic malignancy. The purpose of this study was to deter mine the efficacy of diffusion-weighted magnetic resonance imaging in differentiating spinal infection and malignancy., Methods: Fifty-one consecutive patients with suspected spinal infection or malignancy were enrolled in the study. Apparent diffusion coefficients (ADCs) of paraspinal soft tissue mass and normal and abnormal vertebral bone marrow were determined on the diffusion-weighted magnetic resonance images of the spine. The mean ADCs of normal and abnormal vertebral bodies in patients with confirmed infection or malignancy were compared using nonparametric tests., Results: ADCs of 69 tuberculous, 9 pyogenic, and 50 malignant vertebral marrow lesions were significantly higher than ADCs of normal marrow. ADCs of malignant bone marrow and 5 paraspinal soft tissue lesions were significantly lower than tuberculosis and pyogenic infection. There was no significant difference between the ADCs of 44 adult and 25 pediatric tuberculous bone lesions or between tuberculosis and pyogenic infection. Using the cutoff ADC of 1.02x10(-3)mm2/s for bone marrow, the sensitivity, specificity, and accuracy were 60.26%, 66.00%, and 62.50%, respectively, for distinguishing infection from malignancy. The sensitivity, specificity, and accuracy increased to 94.12%, 82.35%, and 90.20%, respectively, when the ADCs of associated soft tissue lesions were higher than 1.17x10(-3)mm2/s., Conclusions: Diffusion-weighted magnetic resonance imaging has limited usefulness for differentiating spinal infection and malignancy.

Congenital anomaly of the female reproductive system is associated with higher rate of infertility, spontaneous abortion, intrauterine growth retardation, premature birth and postpartum bleed. Because of the variable clinical pictures of obstruction of menstrual flow in adolescence to hypomenorrhea, vaginal discharge, dyspareunia, and fertility problems in adult life, early and accurate diagnosis is difficult. Complete uterine and vaginal septum can be easily confused with uterus didelphys. Management of these two müllerian duct anomalies is different. With improved treatment methods for complete relief of symptoms and prevention of further sequelae, comprehensive evaluation is important to identify the underlying problem and formulate appropriate therapeutic plan. The embryology, classification, and clinical presentation of uterine malformation, advantages and limitations of diagnostic methods including hysterosalpingogram, ultrasound, magnetic resonance imaging, laparoscopy, and hysteroscopy are discussed. The imaging features of different types of uterine anomalies are illustrated.

This paper illustrates the technique and clinical use of cerebral MR venography (MRV). Dural sinus thrombosis is detected by both two-dimensional time-of-flight (TOF) and three-dimensional phase-contrast (PC) techniques. Venous angiomas are demonstrated by the three-dimensional PC method. The arterial feeders, nidus and draining veins of cerebral arteriovenous malformation (AVM) can be visualized on contrast-enhanced TOF three-dimensional MR angiogram. The high-flow draining veins of cerebral and dural AVMs, vein of Galen malformation and carotid cavernous fistula are better seen on contrast-enhanced three-dimensional gradient-echo MRV.

MRI is multiplanar, has large field of view, superior contrast resolution and no known adverse effect on the reproductive potential of ovaries. It is useful for characterizing solid, cystic or necrotic tissue, blood and fat. Contrast-enhanced MRI is also a comprehensive examination of the entire pelvis including lymph nodes, peritoneum, pelvic sidewalls, bone and muscles. It provides information about areas difficult to assess surgically, can refine staging classification, assists in planning surgery or radiotherapy and may be more cost-effective by limiting use of surgery. This is a pictorial essay of MRI assessment of female pelvic neoplasm.

Patients with spinal arteriovenous malformation (AVM) have progressive or fluctuating neurological dysfunction because of hemorrhage, venous hypertension, vascular steal phenomenon, or mass effect from venous varicosity. Spinal AVM is classified into four types based on angiographic and operative findings. Conventional diagnostic methods include magnetic resonance imaging (MRI), supine myelogram, and angiogram. MRI can localize the vascular nidus in the cord, but it may sometimes be normal. Spinal angiogram is the definitive diagnostic modality. It is technically demanding and time consuming, requiring catheterization of all spinal vascular pedicles. MR angiography is fast and multiplanar, and it may shorten the duration of catheter angiography by demonstrating the level of feeders. Images of MRI, magnetic resonance angiography (MRA), and catheter angiogram are presented to illustrate the correlation and diagnosis of spinal AVM.

Hamartoma, lipoma and fat necrosis are benign fatty tissue lesions that may present as breast lumps. The mammographic appearance may be distinctive allowing imaging diagnosis without biopsy. The characteristic feature of hamartoma is that of a compressible mass containing radiolucent fat interchanged with dense fibrous connective tissue surrounded by a thin radioopaque pseudocapsule. Lipomas are radiolucent with well-defined thin smooth capsule. Twenty-seven percent of fat necrosis appears as discrete round or oval radiolucent oil cyst with thin capsule and egg-shell calcification.

Tuberculomas (TB) can mimic brain tumors and abscesses. We performed prospective magnetization transfer ratio (MTR) analysis on 60 patients with 52 intracranial TB, 13 pyogenic abscesses and 65 tumors to determine the efficacy of magnetization transfer (MT) imaging in the differential diagnosis of brain tumors and infection. The nonenhancing cores of TB had significantly higher (P=.026) MTR (0.14+/-0.29) than necrotic components of high-grade gliomas (-0.19+/-0.22). The MTR of cores of TB were also higher than those of the cystic areas of low-grade gliomas (-0.53+/-0.32), benign (-0.09+/-0.21) and malignant (-0.07+/-0.25) tumors, and abscesses (-0.03+/-0.13), but the differences were not significant because of the small number of tumors and abscesses. There was also no significant difference between the MTR of abscesses, malignant and benign tumors. Using the criteria of MTR of necrotic center > 0.14 (mean MTR of TB) for diagnosing TB, MTR <-0.03 (mean MTR of abscesses) for diagnosing tumors and MTR between these values for diagnosing abscesses, MTI had diagnostic sensitivity of 68.42%, specificity of 80.49%, and accuracy of 76.67%. The improved diagnostic accuracy of MRI with the addition of MTR analysis from 86.67% to 91.67% and from 85.71% to 87.50% for both radiologists respectively was not significant. MTR analysis helped us to differentiate solitary TB or abscess from low-grade glioma in five patients and to diagnose multiple TB, abscesses, and metastases in four.

Objective: To evaluate the efficacy of magnetic resonance imaging (MRI) for distinguishing tuberculosis from other types of meningoencephalitis., Patients and Methods: MRIs of 100 patients with tuberculous (50), pyogenic (33), viral (14), or fungal (3) meningoencephalitis were analyzed independently by 2 radiologists. Number, size, location, signal characteristics, surrounding edema, and contrast enhancement pattern of nodular lesions; location and pattern of meningeal enhancement; extent of infarct or encephalitis and hydrocephalus were evaluated., Results: Contrast-enhancing nodular lesions were detected in patients with tuberculous (43 of 50 patients), pyogenic (9 of 33), and fungal (3 of 3) infections. No nodules were detected in patients with viral meningoencephalitis. Using the criteria of 1 or more solid rim or homogeneously enhancing nodules smaller than 2 cm, the sensitivity, specificity and accuracy for diagnosing tuberculous meningitis were 86.0%, 90.0% and 88.0%, respectively., Conclusion: Magnetic resonance imaging is useful in distinguishing tuberculous from pyogenic, viral and fungal meningoencephalitis.

Magnetization transfer (MT) imaging has been used to characterize tissues. A prospective analysis of magnetization transfer ratio (MTR) was performed on 107 patients with brain tumors, infection, and infarction to determine its efficacy in differential diagnosis. MTRs of brain tumor, infection, and infarction were significantly lower than those of normal gray and white matter. The cystic centers of infection had significantly higher MTRs than infarct and cystic tumors. The MTRs of infarction were significantly higher than those of cystic low-grade gliomas and benign tumors. The non-enhancing cystic components of infection, low-grade gliomas, and benign tumors were readily distinguished from solid infarction on enhanced images without MT. Using the MTR of 0.01 as a cutoff, the sensitivity, specificity, and accuracy of MT imaging for distinguishing cystic infection from cystic tumors were 90.00%, 75.86%, and 79.49%, respectively. MT imaging may be valuable in differentiating cystic infection from cystic neoplasm. J. Magn. Reson. Imaging 2000;12:395-399., (Copyright 2000 Wiley-Liss, Inc.)

Magnetic resonance imaging provides a good-quality image over the entire length of the spine and can assess the morphology of the discs and cord. It is the imaging modality of choice in the investigation of spinal diseases. Magnetic resonance myelography (MRM) is non-invasive, has comparable sensitivity to conventional myelography in visualizing lumbar nerve roots and allows overall assessment of the spinal canal even in the presence of cerebrospinal fluid block. Seventy-two patients with pre-surgical diagnosis of disc herniation were prospectively investigated prior to surgery to determine the value of MRM in the diagnosis of disc herniation and spinal stenosis. The difference between the sensitivity and accuracy of MRI (89.0-95.6%, 89.1-95.7%) and MRM (82.4-89.0%, 82.6-89.1%) was not significant for both observers. There was no significant improvement with the addition of MRM to MRI (91.2-97.8%, 91.3-97.8%). Although MRM did not significantly improve the diagnostic accuracy of MRI, it allowed a better overall view of the dural sac and root sleeves, therefore making it easier to diagnose spinal stenosis and disc herniation in a minority of cases.

More than 10% of retroperitoneal paragangliomas are malignant. Histopathological appearance is unreliable in distinguishing benign from malignant paragangliomas. In this study the computed tomography (CT) features of retroperitoneal paragangliomas were analysed to determine if benign neoplasms could be distinguished from malignancy by their appearance at imaging. We reviewed the clinical profiles and CT scans of 27 benign and seven malignant retroperitoneal paragangliomas in 32 patients to determine the presence of any characteristic appearances of benign and malignant neoplasms. Extra-adrenal paragangliomas were more frequently malignant (50%) than adrenal neoplasms (12.5%). Benign lesions were generally smaller (average 6.1 cm) than malignant lesions (average 7.9 cm). Benign tumours were more likely to be homogeneous (46.2%) and have well-defined margins (92.3%) than malignant tumours (25 and 12.5% respectively). Larger tumours were more frequently necrotic. Malignant retroperitoneal paragangliomas infiltrated adjacent liver, pancreas, bowel, lymph nodes, blood vessels, or metastasized to bone and liver. Malignant retroperitoneal paragangliomas are frequently extra-adrenal, large and heterogeneous, with ill-defined margin and necrosis. CT is useful for delineating the location, extent and nature of these tumours. Infiltration of surrounding tissues or organs, metastases, and resectability are accurately assessed by CT.

Sarcomas of the abdomen and pelvis are rare malignant mesenchymal neoplasms that often remain undiagnosed until they attain large size. Complete tumour resection is associated with improved patient survival. Detection and delineation of the tumour, its extent and its relationship with surrounding tissues are important for surgical planning. Radiography, barium studies, and intravenous urography are of limited value in the imaging diagnosis of abdominal and pelvic sarcomas. Ultrasound is sensitive for detecting neoplasms larger than 6 cm. Computed tomography is useful for detection, defining extent, and predicting resectability of the primary tumour, evaluation of response to treatment, and detecting recurrence and metastasis. Sarcomas are predominantly large, poorly demarcated, heterogeneous masses of muscle density with haemorrhage or necrosis.

Primary intrathoracic malignant fibrous histiocytoma and angiosarcoma are rare sarcomas constituting less than 0.2% of lung cancers. The typical imaging appearance is a large, well-circumscribed, non-cavitating, non-calcified, peripheral lung mass without hilar or mediastinal lymphadenopathy. Bronchoscopy and percutaneous needle aspiration are of limited value in differential diagnosis, and thoracotomy is warranted for definitive diagnosis.

Abdominal and pelvic neurogenic tumours are uncommon neoplasms in adults apart from those tumours found in patients with neurofibromatosis. Malignant degeneration occurs in 2.4-29% of neurofibromatosis. Biopsy of neurofibromas can be complicated by sensorimotor nerve deficit. Distinction of malignancy by imaging may circumvent biopsies of asymptomatic benign neurogenic tumours. Benign neurogenic neoplasm is suspected on CT scan if the tumour is in the region of known nerve ganglia or pathway, and is well demarcated, solid, homogeneous, hypodense relative to muscle, and enhances with contrast material. Malignant neurogenic tumours are often large, irregular, infiltrative, and necrotic with heterogeneous contrast enhancement. Computed tomography is valuable in distinguishing malignant from benign neurogenic neoplasms, predicting resectability, detecting distant metastases, and evaluating response to treatment.

Unlabelled: Lymphoscintigraphy allows functional assessment of lymphatic transport and depiction of regional lymph nodes, is fast and nontraumatic and has no known side effects. We retrospectively analyzed lymphoscintigraphic studies to determine their efficacy in the investigation of chyluria, chyloperitoneum and chylothorax., Methods: Twenty-one whole-body lymphoscintigrams using 99mTc-antimony sulfide colloid or dextran were acquired in 18 patients with chyluria, chyloperitoneum and/or chylothorax. The images were reviewed to assess the rate of tracer transport and number, size and distribution of lymph vessels and nodes as well as the presence of collateral, fistula or lymph reflux., Results: Lymphoscintigraphy was normal (5 of 11 patients) or showed lymphatic obstruction (6 of 11 patients) in chyluria associated with filariasis. Lymphatic obstruction was demonstrated in chyloperitoneum and/or chylothorax associated with liver cirrhosis (2 patients), postoperative (1 patient) or congenital (1 patient) lymphatic dysplasia, inferior vena cava obstruction (1 patient) and nephrotic syndrome (1 patient). Enhanced lymph flow was seen in systemic lupus erythematosus (1 patient). Follow-up lymphoscintigrams showed patency of lymphovenous anastomosis (1 patient), improvement (1 patient) or no change (1 patient) in lymphatic drainage after treatment., Conclusion: Lymphoscintigraphy can demonstrate abnormal lymphatic drainage in chyluria, chyloperitoneum and chylothorax. It is useful for selecting patients for surgery and assessing the effect of treatment.

Purpose: Differentiation of recurrent nasopharyngeal carcinoma (NPC) from radiation fibrosis using conventional diagnostic methods can be difficult. The authors prospectively studied patients with NPC to determine the efficacy of Tc-99m MIBI scintigraphy in detecting the primary, residual, and recurrent tumors., Materials and Methods: The authors performed Tc-99m MIBI SPECT studies of the head and neck and whole-body scans on 21 healthy adult volunteers and 43 patients with NPC before (n = 26) or after (n = 17) radiotherapy. The images were qualitatively assessed by comparing the nasopharyngeal uptake to scalp radioactivity. MIBI uptake index was calculated as a ratio of mean counts per pixel in the normal nasopharynx or tumor to mean counts per pixel in the scalp., Results: There was significantly higher uptake of Tc-99m MIBI by NPC than normal nasopharynx and radiation fibrosis (P < .05). The authors determined the optimum cutoff MIBI uptake index value of 1.3 with a sensitivity of 97%, a specificity of 100%, a positive predictive value of 100%, a negative predictive value of 96%, and an accuracy of 98% for diagnosing NPC., Conclusion: This study suggests that Tc-99m MIBI SPECT is useful for detecting primary NPC and for differentiating residual or recurrent tumor from radiation fibrosis. The authors propose the cutoff MIBI uptake index value of 1.3 for diagnosing NPC.

Lymphangiomas are congenital malformations of the lymphatics that are curable by extirpation. Accurate delineation of lesion extension is important for pre-operative diagnosis, surgical planning, and assessing recurrence. The radiologic findings were retrospectively evaluated to determine the imaging appearance of these benign tumours. The plain radiographs, barium meal, ultrasound, CT, and MR images of 18 patients with one or more pathologically proved lymphangiomas were reviewed. Plain radiography and barium study showed masses displacing adjacent organs. Ultrasound examination showed uni- or multilocular cystic masses with smooth, thin or irregular, thick walls. Enhancement of the cyst wall was variable on CT and MR studies. The CT density of the fluid ranged from -4 to 34 HU depending on the lipid content and the presence of haemorrhage. The cysts were isointense to muscle on T1-weighted and hyperintense to fat on T2-weighted MR images. The MR imaging delineated the tumour lesion extension more clearly than ultrasound and CT scans. Ultrasound, CT, and MR imaging are valuable for evaluating lymphangiomas. Magnetic resonance imaging allows accurate determination of lesion extension.

Intestinal lymphangiectasia is a common cause of protein-losing enteropathy characterized by diarrhea, generalized edema, enteric protein loss, hypoproteinemia, and lymphopenia. Diagnosis is based on demonstration of enteric protein loss and characteristic small bowel mucosal histology. Various imaging modalities including barium studies, computed tomography, and lymphangiography have had limited clinical use. The authors report a case of intestinal lymphangiectasia in which Tc-99m dextran lymphoscintigraphy played a significant role in the patient management.

Purpose: Delayed cerebral necrosis (DN) is a significant risk for brain tumor patients treated with high-dose irradiation. Although differentiating DN from tumor progression is an important clinical question, the distinction cannot be made reliably by conventional imaging techniques. We undertook a pilot study to assess the ability of proton magnetic resonance spectroscopy (1H MRS) to differentiate prospectively between DN or recurrent/residual tumor in a series of children treated for primary brain tumors with high-dose irradiation., Methods and Materials: Twelve children (ages 3-16 years), who had clinical and MR imaging (MRI) changes that suggested a diagnosis of either DN or progressive/recurrent brain tumor, underwent localized 1H MRS prior to planned biopsy, resection, or other confirmatory histological procedure. Prospective 1H MRS interpretations were based on comparison of spectral peak patterns and quantitative peak area values from normalized spectra: a marked depression of the intracellular metabolite peaks from choline, creatine, and N-acetyl compounds was hypothesized to indicate DN, and median-to-high choline with easily visible creatine metabolite peaks was labeled progressive/recurrent tumor. Subsequent histological studies identified the brain lesion as DN or recurrent/residual tumor., Results: The patient series included five cases of DN and seven recurrent/residual tumor cases, based on histology. The MRS criteria prospectively identified five out of seven patients with active tumor, and four out of five patients with histologically proven DN correctly. Discriminant analysis suggested that the primary diagnostic information for differentiating DN from tumor lay in the normalized MRS peak areas for choline and creatine compounds., Conclusions: Magnetic resonance spectroscopy shows promising sensitivity and selectivity for differentiating DN from recurrent/progressive brain tumor. A novel diagnostic index based on peak areas for choline and creatine compounds may provide a simple discriminant for differentiating DN from recurrent or residual primary brain tumors.

Objective: To prospectively compare inversion recovery (IR) fast spin-echo (FSE) with T1-weighted spin-echo (SE) and T2-weighted chemical-shift fat-saturated (FS) FSE magnetic resonance sequences in the detection of bone marrow abnormality., Design: Twenty-nine sets of T1-weighted SE [400-640/10-20 (TR/TE)], T2-weighted FS-FSE [2400-3800/91-112/8 (TR/TE/ETL), and IR-FSE [3700-6000/12-14/170/8 (TR/TE/T1/ETL)] images were acquired with a 1.5-T magnet in 27 patients with bone marrow lesions. The visibility, margination, and extent of 41 lesions, image quality, contrast, and artifacts were qualitatively and quantitatively compared., Results: The lesions were more conspicuous on the IR-FSE than on the T1-weighted SE and T2-weighed FS-FSE images. The extent of lesions was similar for all three sequences. Image quality was better and there were fewer motion artifacts on the T1-weighted images. The mean lesion contrasted-to-noise ratio was significantly higher on the T1-weighted images (p < 0.05)., Conclusion: The IR-FSE sequence is highly sensitive for detecting bone marrow pathology, with scan time comparable to the T1-weighted SE and T2-weighted FS-FSE sequences.

Sclerotic and lytic bone changes of tuberous sclerosis (TS) can mimic bone metastases. We report a case of bone metastases from bronchogenic carcinoma in a patient with TS bone changes. Bone scintigraphy and magnetic resonance imaging are useful in distinguishing the TS bone lesions from bone metastases.

Objective: Gradient-echo pulse sequences can reduce imaging time and decrease motion artifacts. If gradient-echo pulse sequences are shown to be comparable to spin-echo sequences in MR imaging of the brain, then gradient-echo imaging can be valuable for examining critically ill, anxious, or uncooperative patients and can increase patient throughput. The purpose of this study was to prospectively compare one fast multiplanar spoiled gradient-recalled acquisition in the steady state (GRASS) (FMPSPGR) sequence with one conventional T1-weighted spin-echo sequence to determine the reliability of the FMPSPGR sequence for detecting cerebral lesions., Subjects and Methods: Fifty-one patients with 142 cranial lesions, including brain tumors, infarction, infection, and noninflammatory lesions, were examined. Forty-two unenhanced and 39 contrast-enhanced FMPSPGR (113-240/2.6-3.6/90 degrees/4 [TR/TE/flip angle/acquisitions]) and spin-echo T1-weighted (400-579/11-12/90 degrees/2) MR images of the head were obtained with a 1.5-T system. The visibility, margination, and extent of the lesions; image quality; contrast; and artifacts were qualitatively and quantitatively compared., Results: Supratentorial lesions were more conspicuous on the unenhanced FMPSPGR images because of the higher signal-to-noise ratio of the normal brain resulting in higher lesion contrast. The higher contrast-to-noise ratio of neoplasms on the contrast-enhanced spin-echo images was not found to be significant in the independent qualitative analysis. The conspicuity and extent of other lesions evaluated with the two pulse sequences were not significantly different for either the unenhanced or the contrast-enhanced studies. Vascular pulsation artifacts were significantly reduced on the contrast-enhanced FMPSPGR images. Susceptibility and chemical-shift phase-cancellation artifacts were more pronounced on the FMPSPGR images., Conclusion: The FMPSPGR sequence provides high-quality images with fewer vascular pulsation artifacts three to four times faster than the spin-echo sequence. The FMPSPGR sequence can reliably show intracranial lesions and can substitute for the T1-weighted spin-echo sequence in routine brain imaging.

Objective: Melioidosis is a tropical infection caused by a gram-negative bacillus, Pseudomonas pseudomallei. The disease manifests initially as localized suppurative lesions and can progress to acute disseminated septicemia with 65-90% mortality if inadequately treated. Musculoskeletal involvement is common. The purpose of this study was to describe the clinical features and imaging appearances of musculoskeletal melioidosis., Design: We retrospectively analyzed the clinical profiles and images of 26 patients diagnosed over a 6-year period as suffering from melioidosis., Patients: The study group comprised 11 patients with musculoskeletal melioidosis and 15 patients with nonmusculoskeletal melioidosis., Results and Conclusions: We found that musculoskeletal melioidosis mimicks other infections both clinically and radiologically. Clinical awareness is therefore crucial, as diagnosis can only be established by bacteriological and immunological studies. Prompt treatment with long-term combination antibiotics in high dosages and surgical drainage of abscesses improves survival.

The authors report a case of splenic hemangiomatosis evaluated by magnetic resonance imaging (MRI). Typical areas of hyperintensity were observed in T2-weighted images. Because it is noninvasive and highly sensitive, MRI proved valuable in suggesting the diagnosis in this patient.

Purpose: To assess imaging features of granulocytic sarcoma (GS) in children with myelogenous leukemia., Materials and Methods: Retrospectively analyzed were radiographs, bone scintigrams, ultrasound (US) scans, computed tomography (CT) scans, and magnetic resonance (MR) images obtained in 30 patients with acute and one with chronic myelogenous leukemia., Results: With one exception in which GS antedated leukemia, GS was present concurrently with onset of leukemia or during remission or relapse. Radiographs, nuclear studies, and US findings were nonspecific. One parascapular GS was hyperintense on T2-weighted MR images, but in all eight central nervous system studies, tumors were isointense to gray matter, muscle, or marrow on T1-weighted images and to white matter or muscle, marrow, or both on T2-weighted images. Contrast enhancement of GS was homogenous on cranial CT scans and all MR studies., Conclusion: CT and MR imaging features may allow distinction of GS from hematomas and abscesses, which are also complications of leukemia. Thus, biopsy may be avoided in some patients.

Objective: We report four cases of CSF enhancement secondary to meningeal carcinomatosis observed during MRI. Only one case has been reported previously., Materials and Methods: Four patients ranging from 4 to 20 years of age, and all having primary or secondary CNS neoplasms, were examined by cranial and/or spinal MRI before and after Gd-DTPA administration. Three of the patients had additional delayed imaging, and subtraction was used in one case., Results: All four patients demonstrated CSF enhancement after Gd-DTPA administration, which increased on delayed imaging and was more apparent following subtraction. Three of the four patients died within 5 months of the MRI examination., Conclusion: CSF enhancement is uncommon, but when seen indicates massive tumor that coats the surface of the CNS. Detection of CNS enhancement may alter therapy; however prognosis may be poor when CSF enhancement is present. Delayed imaging and subtraction may improve detection of CSF enhancement.

Tc-99m MDP bone imaging in spinal tuberculosis usually shows increased radioactivity at the sites of involvement. Uncommonly, the bone scan can be normal if the infection is low grade, indolent, or severely destructive. Two cases of spinal tuberculosis with normal bone imaging are reported. A normal bone image does not exclude tuberculous spondylitis. If there is clinical suspicion of this disease, further investigations, including tissue specimens, should be obtained.