Usefulness of T2 ratio in the diagnosis and prognosis of cardiac amyloidosis using cardiac MR imaging.

PURPOSE: To detect if a difference of T2 ratio, defined as the signal intensity (SI) of the myocardium divided by the SI of the skeletal muscle on T2-weigthed cardiac magnetic resonance (CMR) imaging, exists between patients with systemic amyloidosis, by comparison to control subjects. To determine if a relationship exists between T2 ratio and the overall mortality. MATERIALS AND METHODS: CMR imaging examinations of 73 consecutive patients (48 men, 25 women; mean age, 63 years±15[SD]) with amyloidosis and suspicion of CA and 27 control subjects were retrospectively analyzed after institutional review board approval. Final diagnosis of CA was retained in case of histological confirmation of CA, typical pattern of CA on imaging and/or positivity of 99Technetium-hydroxymethylene diphosphonate scintigraphy. Patients were divided in 2 groups according to the presence or the absence of CA. T2 ratios were calculated in patients with and those without CA and in control subjects with using analysis of variance. Prognostic value of T2 ratio was studied with a Kaplan-Meier curve. RESULTS: Thirty-five patients (51%) had CA and 33 (49%) were free from CA. T2 ratio was lower in patients with CA (1.18±0.29) than in patients without cardiac involvement (1.37±0.35) (P=0.03) and control subjects (1.45±0.24) (P=0.004). A T2 ratio of 1.36 was the best threshold value for predicting CA with a sensitivity of 63% and a specificity of 73%. Kaplan-Meier analysis showed a significant relationship between a shortened overall survival and a T2 ratio<1.36. CONCLUSION: Patients with CA exhibit lower T2 ratio on CMR imaging by comparison with patients free of CA and control subjects.

Mydriasis revealing vascular and osteodural compression of the oculomotor nerve: An observational study on five cases.

PURPOSE: To describe a form of neurovascular compression of the third cranial nerve (CNIII) in idiopathic mydriasis, in which a neurovascular "conflict" exists between the oculomotor nerve, the posterior communicating artery and the clinoid process, using high-resolution magnetic resonance imaging (MRI) with fast imaging employing steady acquisition (FIESTA) sequences. METHODS: An 18-month prospective, observational and monocentric case series report was performed. MRI was performed on 5 consecutive patients with idiopathic, unilateral, persistent and nonreactive mydriasis (pure intrinsic palsy of the CNIII). Patients with diplopia, ptosis or ophthalmoplegia were excluded. Cerebral MRI focused on the CNIII pathway from the mesencephalon to the cavernous sinus entry, particularly on the cisternal segment: image acquisition was performed on a 3 Tesla MRI; the protocol included fast imaging employing steady acquisition (FIESTA) and three-dimension time of flight (3D TOF) sequences. RESULTS: All patients presented a neurovascular compression point, involving the CNIII clamped between a tortuous posterior communicating artery (PCoA) and the posterior clinoid process at the entrance of the cavernous sinus. No cases occurred in the root entry zone. There was no compression on the contralateral side. No tumors or aneurysms were found. Thus, the mydriasis was caused by CNIII compression. CONCLUSION: MRI, including FIESTA sequences, revealed a new type of neurovascular conflict between the CNIII, PCoA and posterior clinoid process in patients with incomplete oculomotor palsy. Non-aneurysmal CNIII compression should be considered as a differential diagnosis in the work-up of idiopathic mydriasis. The role of MRI in the work-up of anisocoria should be considered.

Imaging strategies before beginning treatment of colorectal liver metastases.

The management of colorectal intrahepatic metastases before resection is multidisciplinary and radiologists and nuclear medicine specialists play a major role. In accordance with the French National Guide for appropriate use of diagnostic imaging, the approach should be multimodal: a chest-abdomen and pelvic (CAP) CT scan and hepatic MRI are mandatory while PET-CT provides important additional information, in particular on intra-abdominal extrahepatic metastases. This multimodal approach emphasizes the importance of early and appropriate use of imaging in these patients, as well as the central role of multidisciplinary meetings in oncology.