Characterisation of carotid atherosclerotic plaque: comparison between magnetic resonance imaging and histology

PURPOSE

The aim of this study was to identify and characterise by magnetic resonance imaging (MRI) carotid plaque constituents such as lipid-rich necrotic core, intraplaque haemorrhage and calcification in patients treated with carotid endarterectomy (CEA) using histological evaluation as the reference standard.

MATERIALS AND METHODS

Nineteen patients (13 men and six women) scheduled for CEA between March and August 2004 were imaged on a 1.5-T scanner (Magnetom Symphony, Siemens, Erlangen, Germany). The protocol included four types of sequences [T1, T2, proton density (PD) and three-dimensional time of flight (3D-TOF)]. Images were reviewed for integrity of the fibrous cap, presence of lipid-rich necrotic core, intraplaque haemorrhage and calcification. Signal intensity was assessed relative to the adjacent sternocleidomastoid muscle. Four cross-sections for each lesion were compared with the corresponding histological specimens and independently reviewed by two radiologists and one pathologist.

RESULTS

MRI detected lipid-rich necrotic core with a sensitivity and specificity of 91.6% and 95.0%, respectively, whereas it defined intraplaque haemorrhage alone with a sensitivity and specificity of 91.6% and 100%, respectively. Calcification was recognised with a sensitivity and specificity of 80% and 93.7%, respectively.

CONCLUSIONS

MRI is able to identify signs of carotid plaque instability with a high sensitivity and specificity. Therefore, it may be useful in evaluating and guiding the treatment of haemodynamically nonsignificant stenoses with a potential embolic risk and, in the future, to assess coronary plaque.

Intraoperative US staging of T in gastric cancer: final results of a blind prospective study

BACKGROUND

In order to improve the accuracy in the assessment of depth of tumor invasion, we performed an ultrasound examination of the resected specimen intraoperatively just after removal by the surgeon (Intraoperative Ultrasonography (IUS). This prospective blind study reports the results obtained with the IUS in the staging of T in a group of 281 patients who underwent curative gastrectomy for gastric cancer.

METHODS

After the removal by the surgeon, the portion of the stomach harboring the tumor was submitted to ultrasonography with a linear 7.5 Mhz probe. An echo-free standoff pad was placed between the probe and the organ; a second echo-free standoff pad was interposed between the stomach and the support surface. The diagnosis of depth of invasion was based on the degree of disruption of the five-layer sonographic structure of the gastric wall.

RESULTS

The IUS staging of T corresponded to the pathological diagnosis in 256 out of 281 cases (overall accuracy 91.1%). The sensitivity in the different classes of T was, respectively, 91.2 in T1m cases, 83.3 in the T1sm cases, 89.6 in the T2 cases, and 93.5% in the T3 cases.

CONCLUSION

The IUS on the resected specimen has a high degree of accuracy in the assessment of depth of tumor invasion and seems to be an important advance in the clinical staging of gastric cancer.