Multislice computed tomography angiography in the diagnosis of coronary artery disease

Multislice CT angiography represents one of the most exciting technological revolutions in cardiac imaging and it has been increasingly used in the diagnosis of coronary artery disease. Rapid improvements in multislice CT scanners over the last decade have allowed this technique to become a potentially effective alternative to invasive coronary angiography in patients with suspected coronary artery disease. High diagnostic value has been achieved with multislice CT angiography with use of 64- and more slice CT scanners. In addition, multislice CT angiography shows accurate detection and analysis of coronary calcium, characterization of coronary plaques, as well as prediction of the disease progression and major cardiac events. Thus, patients can benefit from multislice CT angiography that provides a rapid and accurate diagnosis while avoiding unnecessary invasive coronary angiography procedures. The aim of this article is present an overview of the clinical applications of multislice CT angiography in coronary artery disease with a focus on the diagnostic accuracy of coronary artery disease; prognostic value of coronary artery disease with regard to the prediction of major cardiac events; detection and quantification of coronary calcium and characterization of coronary plaques. Limitations of multislice CT angiography in coronary artery disease are also briefly discussed, and future directions are highlighted.

SPECTRUM OF FUNCTIONING ISLET CELL TUMOR ON MULTISLICE COMPUTED TOMOGRAPHY:EXPERIENCE ON 70 PATIENTS

Objective To review experience in preoperative detection of islet cell tumors using multislice computed tomography （MSCT） and summarize various imaging features of functioning islet cell tumors on enhanced MSCT. Methods Seventy patients with clinical or pathological diagnosis of functioning pancreatic islet cell tumor between October 2003 and February 2007 were included in this retrospective study. Seventy-four enhanced MSCT scans in these patients were identified. All MSCT scans were interpreted by two experienced radiologists by consensus interpretation. Surgery and pathology reports were used to confirm the diagnosis, localization, and size of tumors. Results Totally, 73 functioning islet cell tumors including 65 benign insulinomas, 2 benign glucagonomas, 3 malignant insulinomas, and 3 malignant glucagonomas were pathologically diagnosed. Tumors in only two cases were not found by MSCT. In 67 benign lesions, 32 showed typical enhancement style, 21 showed prolonged enhancement in portal venous phase, 4 showed delayed enhancement, 4 had iso-dense enhancement with normal pancreatic parenchyma, 2 had no enhancement at all in arterial phase and portal venous phase, and 4 had inhomogeneous enhancement with necrosis or cyst-formation. Patchy or spotty calcifications were found in 3 of the 67 tumors. In 6 malignant islet cell tumors, vessel invasion （2/6） and bowel invasion （1/6） were seen. Different enhancement patterns were shown. All hepatic metastases showed hyper-enhancement during their arterial phase. Conelttsions Pancreatic islet cell tumor may display a wide spectrum of presentations in MSCT. Tumors with unusual appearances often present as diagnostic challenges. Non-contrast and post-contrast multiphase scans are recommended for the localization of functioning islet cell tumors.

Quantitative and qualitative assessment of non-obstructive left main coronary artery plaques using 64-multislice computed tomography compared with intravascular ultrasound

Background There are few reports of quantitative and qualitative measuring of left main coronary artery （LMCA） plaques by multislice computed tomography coronary angiography （MSCTA）, especially when compared with intravascular ultrasound （IVUS） as reference standard. The aim of this study was to evaluate the use of 64-MSCTA in the diagnosis of LMCA disease, and the accuracy of MSCTA in the quantitative and qualitative assessment of the LMCA lesion as compared with IVUS.Methods A total of 91 patients （53 men, 38 women, mean age （64.78±9.19） years） were examined by 64-MSCTA and IVUS. Compared with the IVUS, the sensitivity, specificity, positive and negative predictive values （PPV and NPV） of the MSCTA on the diagnosis of LMCA diseases were calculated. Also, kappa index （K） for the agreement between MSCTA and IVUS was calculated. Minimal lumen area （MLA）, external elastic membrane cross-sectional area （EEM-CSA） and plaque burden were measured by two blinded and independent operators on MSCTA cross-sectional reconstruction and compared with the parameters measured from IVUS by manually tracing. The CT value of soft, fibrous and calcific plaques was measured using IVUS classification of the plaques.Results The sensitivity, specificity, PPV and NPV of MSCTA for detecting LMCA plaques were 93.1%, 84.2%, 95.7%, 76.2%, respectively. Kappa index （K=0.744, P〈0.001） indicated excellent agreement between MSCTA and IVUS. The Pearson index between MLA on IVUS and MLA on MSCTA was 0.815 （P 〈0.01）. The Pearson index of plaque burden and EEM-CSA between IVUS and MSCTA was 0.736 and 0.740 respectively （both P 〈0.01）. The CT value of soft plaque, fibrous plaque and calcific plaque compared with IVUS were （52.52±15.71） HU, （108.32±43.44） HU and （604.16±377.67） HU （P〈0.001）. Receiver operating characteristic curve analysis of CT value of non-calcific plaques for predicting soft plaques showed the cutpoint was 54.35 HU, with a sensitivity of 83.3% and specificity of 94.4%. Conclusions Sixty-four section MSCTA is an effective diagnostic tool for the detection of LMCA plaques with higher sensitivity and specificity. The correlation of quantitative and qualitative analysis between MSCTA and IVUS was excellent. The CT value of plaques can help the diagnosis of plaque composition.

Role of contrast enhanced ultrasound in detection of abdominal aortic abnormalities in comparison with multislice computed tomography

Conventional ultrasound （US） is the most widely used imaging modality in routine clinical practice worldwide. The limitations of conventional ultrasound in the detection of aortic lesions versus multi-slice computed tomography angiography （MS-CTA） are well known.

The accuracy and optimal slice thickness of multislice helical computed tomography for right and left ventricular volume measurement

Background Multislice helical computed tomography (MSCT) has been used to depict coronary anatomy noninvasively, and proved useful for evaluating ventricular function. The aim of our study was to assess the accuracy of ventricular volume as measured by MSCT.Methods Fourteen human left ventricular (LV) and 15 right ventricular (RV) casts were scanned by MSCT. A series of LV and RV short-axis images were reconstructed later with slice thickness of 2.0 mm, 3.5 mm, 5.0 mm, 7.0 mm, and 10.0 mm. Ventricular volume was calculated by the multislice tomographic Simpson’s method. True LV and RV cast volumes were determined by water displacement. Results Both calculated LV and RV volumes correlated highly with the corresponding true volumes (all r>0.95, P<0.01). But with slice thickness from 2.0 mm to 10.0 mm, MSCT scanning overestimated the corresponding true volume by (3.21±5.95) ml to (12.58±8.56) ml for LV and (10.22±8.45) ml to (23.91±12.24) ml for RV (all P<0.01). There was a very high correlation between the overestimation and the selected slice thickness for both LV and RV volume measurements (r=0.998 and 0.996, P<0.01, respectively). However, when slice thickness was reduced to 5.0 mm, the overestimation for both LV and RV volume measurements became nonsignificant for slice thickness from 2.0 mm to 5.0 mm. Conclusions Both LV and RV volumes can be accurately estimated by MSCT. Thinner slice has more accurate calculated volume. However, 5.0 mm slice thickness is thin enough for an accurate measurement of LV or RV volume.

A pilot study on diagnosis of coronary artery disease using computed tomography first-pass myocardial perfusion imaging at rest

Background:Although computed tomography coronary angiography (CTCA) can identify coronary stenosis,little data exists on the ability of multislice computed tomography (MSCT) to detect myocardial perfusion defects at rest.Methods:In 33 patients with diagnosed or suspected coronary artery disease (CAD),CTCA using retrospective electrocardiography (ECG) gating at rest and invasive coronary angiography (ICA) was performed.The 2D myocardial images were reconstructed in diastolic and systolic phases using the same raw data for CTCA.CT values of the myocardium were used as an estimate of myocardial enhancement,which were shown by color mapping.Myocardial ischemia was defined as a pattern of transient endocardial hypo-enhancement at systole and normal enhancement at diastole.The results of ICA were taken as the reference standard.Results:When a diameter reduction of more than 50% in ICA was used as diagnostic criteria of CAD,the sensitivity,specificity,positive predictive value (PPV),and negative predictive value (NPV) of CT first-pass myocardial perfusion imaging (MPI) at rest were 0.85,0.67,0.92,and 0.50 per patient,respectively,and 0.58,0.93,0.85,and 0.76 per vessel,respectively.Conclusions:CT first-pass MPI at rest could detect CAD patients,which could become a practical and convenient way to detect ischemia,consequently offering the ability for MSCT to act as a "one stop shop" for the diagnosis of CAD.

A New Method of 3-Dimensional Localization of Intraocular Foreign Bodies Using CT Imaging:A Role of Optic Nerve

Computed tomography（CT） is considered the most sensitive method for the detection of intraocular foreign bodies（IOFBs）. The purpose of this study was to evaluate a new method of 3-dimentional（3D） localization of IOFBs that takes advantage of the anatomical structure of the optic nerve and to assess the clinical outcomes using this new method. Twenty-two trauma patients with IOFBs or suspected IOFBs admitted to our hospital were scanned with multislice CT（MSCT） between July and December 2003. All scanning was performed with a 16-row spiral CT in axial plane using a sequential scanning protocol. During the scanning, the eyeball of the patient was kept stable and was not allowed to rotate internally or externally. Section collimation was set at 16 mm × 0.75 mm. Table feed was 12 mm. Reconstruction index was 0.75 mm. After scanning, the reconstructed images were loaded into a workstation to create the multiplanar reconstruction images with the aid of the 3D software. We compared the localization results with the operative findings. Multiplanar reconstruction images showed IOFBs in all 22 patients. IOFBs occurred in the eyeball of 14 patients, in the wall of the eyeball of 5 patients and in the posterior orbits of 3 patients. Different surgical procedures were designed according to the localization by this new method and all IOFBs were successfully removed. All of these foreign bodies were metallic and the localization of IOFB using MSCT was consistent with that found by operative findings. It was suggested that MSCT is a simple and effective imaging modality for the localization of IOFBs. In our study, we localized the IOFBs more quickly and accurately by taking advantage of the fixed position of the intraocular segment of the optic nerve, and determined the necessary surgical parameters.

Calcific degeneration and rupture of the aortic valve and ascending aorta： from cardiac auscultation to multimodality imaging

A 76-year-old Caucasian woman was admitted to the emergency room and referred for cardiac evaluation for dyspnea and abrupt onset of cough three weeks ago. She had a history of well-controlled arterial hypertension and was on adequate oral anticoagulant therapy for permanent atrial fibrillation. Previous thoracic injuries, connective tis- sue disorders or recent infections were excluded. No chest pain or syncope was reported. mmHg in both arms, heart rate Blood pressure was 150/50 was 90 beats/min.

Different therapeutic proportion of patients undergone coronary angiography in the era of development in MSCT

Objective To study the different therapeutic proportion of the patient populations undergone coronary angiography(CAG)in the era of development in multislice spiral computed tomography(MSCT).Methods Two hundred and fifty four consecutive patients(mean age 59.24±10.65),who underwent CAG at Daxing Hospital from February 2007 through October 2007,were enrolled,160 patients were male and 94 were female.By evaluating from the coronary angiogram,the patients were not diagnosed to have coronary heart disease(CHD)with less than 50%diameter stenosis of coronary artery;the patients to have CHD with more than or equal to 50%stenosis of coronary artery;the patients were performed the procedure of percutaneous coronary intervention(PCI)with more than or equal to 70%stenosis;the patients were proposed to have coronary aortic bypass graft(CABG)surgery with left main coronary artery lesions or diffuse triple coronary artery lesions.Results In the 254 consecutive patients,59 patients(23.2%)had not been diagnosed to have CHD;195(76.8%)to have CHD,of these patients with CHD,49 patients(19.3%)were not indicated for PCI(including the patients receiving follow-up coronary angiography after stenting),81(31.9%)had been performed the procedure of stent implantation,57(22.4%)proposed to have CABG,8(3.1%)the procedure of PCI had not been successful,or had not been performed because of patients opposing to this therapy.Conclusion Multislice spiral computed tomography can be applied as a non-invasive screening tool to exclude the presence of CHD,to increase the positive proportion of the populations with CHD in all patients receiving coronary angiograhpy,to avoid the use of CAG in a subset of patients.