Cerebral computed tomography angiography using a low tube voltage (80 kVp) and a moderate concentration of iodine contrast material: a quantitative and qualitative comparison with conventional computed tomography angiography.

OBJECTIVE: To investigate the feasibility of an 80-kVp protocol using a moderate concentration contrast material (MC-CM) for cerebral computed tomography angiography by comparison with a conventional 120-kVp protocol using a high concentration contrast material (HC-CM). MATERIALS AND METHODS: Attenuation values and signal-to-noise ratios (SNRs) were determined in a head phantom for 2 tube voltages (80 and 120 kVp) and 2 different iodine concentration contrast materials (HC-CM and MC-CM). Among 90 consecutive patients, 45 patients were scanned with 120 kVp and 150 mAs(eff) after administration of 70 mL of HC-CM (370 mg iodine [mgI]/mL), whereas the other 45 patients were scanned with 80 kVp and 370 mAs(eff) after administration of 70 mL of MC-CM (300 mgI/mL). The Hounsfield units (HU) of the internal carotid artery T junction, SNR, contrast-to-noise ratio (CNR), subjective degree of arterial enhancement, image noise, sharpness of the cerebral arterial boundary, and overall diagnostic image quality were compared between the 2 groups. RESULTS: The mean attenuation of the internal carotid artery T junction, SNR, and CNR was significantly higher in the 80 kVp with MC-CM group (379.2, 33.7, and 31.1 HU, respectively) than in the 120 kVp with HC-CM group (282.2, 31.1, and 27.2 HU, respectively). The 80-kVp protocol resulted in significantly higher score in arterial enhancement, sharpness of the cerebral arteries, and overall diagnostic image quality. The effective dose of 80 kVp (0.7 mSv) was 22.2% lower than that of 120 kVp (0.9 mSv). CONCLUSIONS: The use of 80 kVp with MC-CM improved arterial enhancement, SNR, and CNR and provided superior quality images using a smaller amount of iodine and a lower radiation dose than the conventional protocol of 120 kVp with HC-CM.

MRI findings of spinal visceral larva migrans of Toxocara canis.

PURPOSE: The purpose of this study is to investigate the MRI findings of visceral larva migrans (VLS) of Toxocara canis in spinal cord. MATERIALS AND METHODS: We retrospectively reviewed spinal MRI findings in eight patients with serologically proven Toxocara canis between 2005 and 2008. We evaluated the location, length, extent and migration of the lesion, MR signal intensity (SI), enhancement pattern, and swelling of the spinal cord. We evaluated clinical features including presenting symptoms and signs and treatment response. RESULTS: Total 8 patients (M=8; age range 36-79 years) were included. The lesions were located in the cervical or thoracic spinal cord in all patients. All lesions showed high SI and minimal or mild swelling of involved spinal cord on T2WI and focal nodular enhancement on posterior or posterolateral segment of spinal cord. The length of involved lesion was relatively short in most patients. There was a migration of lesion in one patient. In spite of albendazole or steroid treatment, neurological symptoms or signs were not significantly improved in all patients. CONCLUSION: Although all lesions show non-specific imaging findings like non-tumorous myelopathy mimicking transverse myelitis, single lesion, focal nodular enhancement on posterior or posterolateral segment of spinal cord, relatively short segmental involvement and migration of lesion may be characteristic findings of spinal VLM of Toxocara canis. In addition, the reluctant response to the treatment may be characteristic of spinal VLM of Toxocara canis.

Comparison of indirect isotropic MR arthrography and conventional MR arthrography of labral lesions and rotator cuff tears: a prospective study.

OBJECTIVE: The purpose of our study was to prospectively compare the diagnostic accuracy of 3D isotropic indirect MR arthrography with conventional sequences of indirect MR arthrography for the diagnosis of labral and rotator cuff lesions on a 3-T MR unit. SUBJECTS AND METHODS: Thirty-six consecutive patients who were scheduled for shoulder arthroscopic surgery at our institution underwent indirect MR arthrography. Both conventional sequences and an additional 3D isotropic sequence were obtained 1 day before arthroscopic surgery. Two musculoskeletal radiologists prospectively evaluated the images in consensus for the presence of superior and anterior labral lesions and subscapularis and supraspinatus-infraspinatus tendon tears using the conventional sequences and the 3D isotropic sequence. We analyzed the statistical difference between the sensitivities and specificities of both methods using arthroscopic findings as the reference standard. RESULTS: Surgical findings confirmed the presence of 23 superior labral lesions, eight anterior labral lesions, 21 subscapularis tears, and 24 supraspinatus-infraspinatus tears. The sensitivity and specificity of the conventional sequences were 74% and 54% for superior labral lesions, 88% and 96% for anterior labral lesions, 67% and 85% for subscapularis tendon tears, and 96% and 75% for supraspinatus-infraspinatus tendon tears. The sensitivity and specificity of the 3D isotropic sequence were 70% and 85% for superior labral lesions, 100% and 100% for anterior labral lesions, 67% and 85% for subscapularis tendon tears, and 96% and 67% for supraspinatus-infraspinatus tendon tears. No statistically significant difference was seen in sensitivities and specificities for both methods. CONCLUSION: Three-dimensional isotropic MR arthrography sequences with multiplanar reconstruction can provide a similar capability for the diagnosis of labral and rotator cuff lesions as conventional MR arthrography sequences but in a shorter imaging time.

Intraductal tubular carcinoma of the pancreas: a case report with the imaging findings.

We describe here a case of intraductal tubular carcinoma of the main pancreatic duct. Gadolinium-enhanced pancreas magnetic resonance (MR) imaging showed an enhancing mass that was confined in the dilated main pancreatic duct of the pancreatic body, along with dilatation of the upstream main pancreatic duct and chronic pancreatitis that was due to obstruction. MR cholangiopancreatography and an endoscopic retrograde pancreatogram showed a filling defect that was due to an intraductal mass of the pancreatic body, along with dilatation of the upstream main pancreatic duct and no dilatation of the downstream main pancreatic duct. The pathological findings demonstrated an intraductal nodular appearance without papillary projection or mucin hypersecretion.

Integrated PET/CT of pulmonary neuroendocrine tumors: diagnostic and prognostic implications.

OBJECTIVE: The purpose of this study was to describe retrospectively integrated PET/CT findings on pulmonary neuroendocrine tumors and to correlate the findings with prognosis. MATERIALS AND METHODS: Between May 2003 and February 2005, 37 consecutively enrolled patients (33 men and four women; mean age, 60 years) with histopathologically proven pulmonary neuroendocrine tumors underwent 18F-FDG PET/CT after enhanced standalone CT. CT was used to analyze the morphologic features of the tumors and PET to measure maximum standardized uptake value (SUV). Maximum SUVs of carcinoid tumors, large-cell neuroendocrine carcinomas (LCNECs), and small-cell lung carcinomas (SCLCs) were compared, and maximum SUV and tumor stage and prognosis were correlated. RESULTS: Four (two typical and two atypical) of the seven carcinoid tumors had no FDG uptake or less than mediastinal uptake. The maximum SUVs of primary tumors, in increasing order, were significantly different for carcinoids (mean, 4.0; median, 3.4), LCNECs (mean, 12.0; median, 10.7), and SCLCs (mean, 11.6; median, 11.7) (p = 0.006, Kruskal-Wallis test). There was no significant correlation between maximum SUV of the primary tumor and the tumor stages of carcinoids, LCNECs, or SCLCs (p = 0.08, Jonckheere-Terpstra test; p = 0.768, Mann-Whitney test). Results of receiver operating characteristics analysis showed a maximum SUV greater than 13.7 suggested a poor survival period in cases of LCNEC and SCLC. CONCLUSION: The maximum SUVs of neuroendocrine tumors are significantly different for carcinoid tumors, LCNECs, and SCLCs, and a high maximum SUV suggests short survival of patients with LCNEC or SCLC.