Hybrid intravascular ultrasound and optical coherence tomography catheter for imaging of coronary atherosclerosis.

OBJECTIVE: To demonstrate the feasibility of imaging human coronary atherosclerosis using a novel hybrid intravascular ultrasound (IVUS) and optical coherence tomography (OCT) imaging catheter. BACKGROUND: IVUS and OCT have synergistic advantages and recent studies involving both modalities suggest the use of a hybrid imaging catheter may offer improved guidance of coronary interventions and plaque characterization. METHODS: A 1.3 m custom hybrid IVUS-OCT imaging probe was built within a 4F catheter using a 42 MHz ultrasound transducer and an OCT imaging fiber. Coplanar images were simultaneously acquired ex vivo by both modalities in 31 arterial segments from 11 cadaveric human coronaries. IVUS and OCT images were acquired at 250 µm intervals, of which 13 of the arterial segments were selected as representative of a diverse set of pathological findings. The selected segments were then imaged with either digital X-ray or micro-CT, processed for histological analysis and compared with the corresponding IVUS and OCT images. RESULTS: Images of human coronary atherosclerosis using the hybrid IVUS-OCT catheter demonstrated a range of vascular pathologies that were confirmed on histology. The anticipated synergistic advantages of each modality were qualitatively apparent, including the deeper tissue penetration of IVUS and the superior contrast, resolution and near-field image quality of OCT. CONCLUSIONS: Preliminary ex vivo images using a hybrid IVUS-OCT catheter demonstrated feasibility in using the device for intracoronary imaging of atherosclerosis. Future studies will include in vivo imaging and larger samples sizes to enable quantitative comparisons of tissue characterization and feature identification using hybrid imaging catheters versus standalone IVUS and OCT imaging techniques. © 2012 Wiley Periodicals, Inc.

Expression of epidermal growth factor receptor in primary colorectal adenocarcinoma predicts expression in recurrent disease.

We tested the usefulness of epidermal growth factor receptor (EGFR) immunostaining in primary colorectal adenocarcinoma as a predictor for EGFR status of tumor recurrences in 33 primary tumors and distant recurrences (July 1994 to June 2005). Representative primary and recurrent tumor sections were stained using mouse anti-EGFR antibodies, and only membranous staining of malignant cells was recorded. Results were reported as negative (no staining), 1+ (positivity in <50% of cells), or 2+ (positivity in >50% of cells). Of 33 cases, 19 (58%) showed the same extent of immunopositivity in primary and recurrent tumors. Bivariate logistic regression analysis of primary tumors with 2+ vs those with negative or 1+ staining showed that the primary tumor status had a major predictive relationship with that of recurrence (odds ratio, of 45.99; confidence limit, 4.0-524.9; P = .0021). The difference between the median time to recurrence of primary tumors with the various degrees of staining was not statistically significant. Our reporting method provides a useful correlation between the staining profiles of primary colorectal adenocarcinoma and recurrent disease. It is exceptionally reliable in predicting immunopositivity of a recurrence when more than 50% of cells of the primary tumor are immunoreactive.

Is EGFR expression altered following postoperative chemotherapy for colorectal adenocarcinoma?

BACKGROUND: There is immunohistochemical evidence to suggest that expression of epidermal growth factor receptor (EGFR) in primary colorectal adenocarcinoma predicts its expression in recurrent disease. This study investigates whether postoperative chemotherapy affects the degree of concordance between EGFR statuses of the two tumors. METHODS: Thirty-three patients were identified from the files of Sunnybrook Health Sciences Center from July 1994 to June 2005. All patients had resection of their primary tumors and their distant recurrences. Eighteen patients received postoperative chemotherapy, 3 of which also received postoperative radiation therapy. Representative primary and recurrent tumor sections were stained using mouse anti-EGFR antibodies and only membranous staining of malignant cells was recorded. Results were reported as negative (no staining), 1+ (positivity in <50% of cells) or 2+ (positivity in >50% of cells). RESULTS: EGFR immunostaining in the 15 patients, who received no postoperative chemotherapy, was decreased in 3 recurrences, remained the same in 10 and increased in 2. In the group of 18 patients who received postoperative chemotherapy, EGFR immunostaining was decreased in 6 recurrences, remained the same in 9 and increased in 3 (p = 0.6598). In patients who received postoperative chemotherapy, the odds ratio for a recurrence to show lower levels of EGFR immunostaining compared to its originally resected primary was 4.75 (CI = 0.94-26.73). CONCLUSION: These preliminary data suggest that recurrences following postoperative chemotherapy are likely to have lower levels of EGFR expression compared to cases who receive no chemotherapy. Although the difference of immunostaining profiles between the two groups was not statistically significant, this observation might impact the management of these patients by targeted biologic therapies and its practical implications need further validation in larger series.

A novel approach to the intraoperative assessment of the uncinate margin of the pancreaticoduodenectomy specimen.

BACKGROUND: Currently, there is no consensus regarding the pancreaticoduodenectomy (PD) margins examined intraoperatively or the technical protocol for frozen section examination. The aim of this work was to summarize our experience regarding the intraoperative examination of the uncinate margin and to compare it with the published literature. MATERIALS AND METHODS: Our local protocol for the intraoperative assessment of the uncinate margin of the PD specimen is described in this article. A PubMed search limited to English language publications using terms along the theme of pancreaticoduodenectomy and margin was performed. Retrieved articles were categorized according to whether they discussed frozen section margin examination. RESULTS: Ten articles published between 1981 and 2005 were retrieved which discussed the intraoperative examination of PD specimens. Of the 10 articles, 5 discussed the intraoperative consultation for diagnostic purposes only, 2 discussed the consultation for both diagnostic purposes and assessment of margins, and 3 discussed intraoperative assessment of margins only. Of the total of five articles that discussed the intraoperative assessment of margins, none detailed the technical protocol for examining the uncinate margin. DISCUSSION: Our proposed protocol for the intraoperative assessment of the uncinate margin of PD specimens allows for its accurate evaluation and has not been described previously in the English literature.

Improved lymph node retrieval in Whipple specimens as a result of implementation of a new uncinate margin protocol.

BACKGROUND: Lymph node status is an important prognostic factor in pancreatic and peri-ampullary adenocarcinoma. We recently changed our protocol for assessment of the uncinate margin of Whipple specimens and noted that lymph nodes were often present in uncinate margin sections. MATERIALS AND METHODS: Whipple specimens from 2004 to 2006 were divided into two groups, those that were handled according to the en face protocol, and those handled according to the radial protocol. The numbers of lymph nodes found in uncinate margin sections were assessed, as well as the total number of nodes found in the specimen. RESULTS: Sixteen cases were handled according to the en face protocol, and 20 according to the radial protocol. In the en face group, 2 benign nodes were found in the uncinate margin (0.1 nodes per case), while in the radial group, 36 nodes (1.8 nodes per case) were identified (p=0.0005). Eight cases in the latter group had positive nodes in the uncinate margin sections. In two of these cases the positive lymph node was the only lymph node with metastasis, and in an additional case the involved node was one of two positive lymph nodes. Total lymph node retrieval was 15.5 lymph nodes per case in the en face group, and 20 nodes per case in the radial group (p=0.02). DISCUSSION: The improved lymph node retrieval may be due to additional nodes found in radial sections of the uncinate margin, or alternatively, due to increased vigilance in specimen handling. In 3 of 20 cases, nodes found in the radial sections influenced staging.