Clinical evaluation of (18)F-fludeoxyglucose positron emission tomography/CT using point spread function reconstruction for nodal staging of colorectal cancer.

OBJECTIVE: For patients with colorectal cancer, lymph node metastasis is a very important factor for prognostic and treatment determinations. Fluorine-18 fludeoxyglucose positron emission tomography/CT ((18)F-FDG-PET/CT) is among the useful tools for detecting lymph node metastasis. Recently, a new (18)F-FDG-PET/CT reconstruction technique for improving spatial resolution and signal-to-noise ratios, point spread function (PSF), has become available. We assessed the effect of PSF reconstruction on standardized uptake values and its diagnostic accuracy for lymph node staging in patients with colorectal cancer. METHODS: We retrospectively analysed records from patients with colorectal cancer who underwent (18)F-FDG-PET/CT for pre-operative staging. All positron emission tomography CT (PET/CT) examinations were reconstructed using ordered subset expectation maximization (OSEM) and OSEM + PSF. We compared sensitivities, specificities, positive-predictive values (PPVs), negative-predictive values (NPVs) and accuracies of conventional PET/CT (reconstructed with OSEM) and PSF-PET/CT (reconstructed with OSEM + PSF) for identifying lymph node metastases. We also analysed the diagnostic confidence level on a 5-point scale. RESULTS: With conventional PET/CT, the sensitivity, specificity, PPV, NPV and accuracy were 53.1%, 99.1%, 94.4%, 88.3% and 89.1%, respectively. With PSF PET/CT, the corresponding values were 65.6%, 99.1%, 95.4%, 91.2% and 91.8%, respectively. Conventional PET/CT and PSF PET/CT did not differ significantly in terms of N-stage definition (p = 0.125). However, the diagnostic confidence level of PSF PET/CT was significantly higher than that of conventional PET/CT (p < 0.01). CONCLUSION: PSF reconstruction might slightly increase sensitivity without impairing specificity. Moreover, this technique is expected to facilitate more confident radiological decisions when compared with conventional PET/CT. Advance in knowledge: This study demonstrates the clinical effectiveness of PSF PET/CT for lymph node staging in colorectal cancer.

[Failure to Remove Long-Term Indwelling Central Venous Catheters in Two Patients].

The use ofa central venous(CV)port system has become common for the treatment of patients with tumors. We report on the failure to remove CV catheters in 2 patients. The first patient was a 50 years woman with acute myeloid leukemia. She underwent CV port implantation via the left brachial approach 11 years previously. The second patient was an 80 years man with a lower gingival carcinoma. He underwent CV port implantation via the left brachial approach 6 years previously. CV catheter removal was attempted in both patients, but was unsuccessful because of strong adhesion to the vessel wall. Based on our experience, if catheter removal is impossible, its retention is more suitable.

Left coronary artery ostial stenosis from Takayasu's arteritis diagnosed using transthoracic color flow and pulsed Doppler echocardiography.

Coronary artery stenosis is seen in 10-45% of patients with Takayasu's arteritis (TA) and coronary ostia are most frequently involved. It may cause angina pectoris and sudden death during the early course of the disease. We describe a 14-year-old girl who first presented with exertional angina and syncope and was diagnosed as having left coronary artery ostial stenosis from TA by using transthoracic echocardiography. This is the first report showing the important role of color flow and pulsed Doppler echocardiography to detect coronary artery stenosis caused by TA.