Characterisation of small hypoattenuating hepatic lesions in multi-detector CT (MDCT) in patients with underlying extrahepatic malignancy: added value of contrast-enhanced MR images.

OBJECTIVE: To retrospectively assess the value of adding gadolinium-enhanced dynamic imaging to standard ununenhanced magnetic resonance imaging (MRI) for characterising hypoattenuating hepatic lesions that are too small to characterise with multi-detector computed tomography (MDCT). METHODS: Informed consent was waved, and institutional review board approval was obtained. Three hundred and forty-six small (≤ 2 cm) lesions (63 metastatic, 283 benign) in 183 patients with underlying carcinoma who underwent hepatic MRI after CT were retrospectively analysed. Two radiologists independently reviewed images and diagnoses were graded on an ordinal scale from 1 (definitely benign) to 5 (definitely malignant). Receiver operating characteristic analysis was used. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were also determined. RESULTS: The areas under the curve of the ununenhanced images alone and with dynamic images were 0.837 and 0.850 for reader 1 (p = 0.616) and 0.771 and 0.783 for reader 2 (p = 0.700). Descriptive statistical values demonstrated sensitivities of 76% and 80%, specificities of 93% and 95%, PPVs of 69% and 79%, NPVs of 95% and 95% and accuracies of 90% and 92%, respectively. CONCLUSION: The value of adding three-phase contrast-enhanced MRI to unenhanced imaging did not reach statistical significance for characterising small hypoattenuating hepatic lesions on MDCT.

Immunoglobulin G4-Related Sclerosing Disease Manifesting as Bilateral Tonsillar Hypertrophy on MR Images: A Case Report.

Immunoglobulin G4-related sclerosing disease (IgG4-SD) is currently recognized as a distinct systemic disease involving various organs. We reported the imaging findings of a case of pathologically confirmed IgG4-SD involving bilateral palatine tonsils. CT and MRI showed diffuse enlargement of both palatine tonsils with homogeneous contrast enhancement. Focal contour bulging was noted in the right palatine tonsil. Lesions appeared as isointense on T1-weighted and slightly hyperintense on T2-weighted MRI images, as compared with muscle. The T2-weighted MRI image showed a striated pattern in both tonsils. Despite its rare occurrence, IgG4-SD should be included in the differential diagnoses of patients with symptomatic bilateral tonsillar hypertrophy that is non-responsive to medication.

An immunoglobulin G4-related sclerosing disease of the small bowel: CT and small bowel series findings.

Immunoglobulin G4 (IgG4)-related sclerosing disease is rare and is known to involve various organs. We present a case of histologically proven IgG4-related sclerosing disease of the small bowel with imaging findings on computed tomography (CT) and small bowel series. CT showed irregular wall thickening, loss of mural stratification and aneurysmal dilatation of the distal ileum. Small bowel series showed aneurysmal dilatations, interloop adhesion with traction and abrupt angulation.