Multidetector-row Computer Tomography Research Articles

Quantification of Target Artery Calcification Using Computed Tomography is Useful to Judge Whether Anastomosis is Feasible or Not in Distal Bypass

Introduction: With increasing diabetic patients, patients with critical limb ischemia requiring distal bypass are increasing. In diabetic patients, severe calcification is common, and if stitch needles for anastomosis are not penetrable, bypass may become unsuccessful. Preoperative information regarding penetrability of needles is very helpful for choosing target segment; however, there have been little studies regarding quantification of calcification for bypass target segment. We performed quantification of calcification by computer tomography (CT) in patients underwent distal artery bypass, and established criteria for feasibility of anastomosis for calcified artery. Methods: After Mar. 2018, 85 patients (mean age 71.8±9.5 years; range 48-91; female 34%; hemodialysis dependent patient 47%) underwent distal bypasses (tibial or peroneal bypasses 21%; para- or infra-malleolar bypass 79%) in our hospital. Of 85, 16 had entire arterial calcification involving target arteries. Before the bypass, arterial segments, with larger caliber and better distal run-off, were selected as first or second-choice target segment for anastomosis, and calcium score of the segments was assessed by Agatston method1): Using multidetector row CT (Revolution CT®, GE Co. USA), 3 dimension configuration of the calcified artery was reconstructed, and 8-10 contiguous slices with a thickness of 2.5 mm each were obtained from about 20mm-long target segment. In each slice, calcified area with CT score≥130 Hounsfield units (HU), and ≥2 pixels was defined to be significant, and the areas were categorized into density scores 1 - 4 depending on CT scores (1 = 130-199, 2 = 200-299, 3 = 300-399, 4 = >399HU), and then, using Ziostation 2®computer software (Zaiosoft co. Japan), Agatston score (AS) for outer half circle area in each slice was calculated by multiplying the density of score and the area (mm2), and presented as 0 (no calcification) to >40 (very severe calcification) (Fig.). Results: Of 85 patients, 16 had entire artery calcification involving target segment, and clampless anastomosis technique was necessary. The target segments were selected by angiography and plain X-P, and their ASs of target segment were obtained before operation. Of 16, 2 had severely calcified target segment, with mean AS 33.4±5.1; range 28.6 - 42.9 (n=12slices), and anastomosis to the first target was unsuccessful. In the remaining14, mean ASs were 16.4±6.2; range 1.0 - 31 (n=132 slices), and most of stitch needles were penetrable without difficulties and anastomosis was successful. As results, anastomosis for calcified segments with AS< 20 was surely possible and needles were penetrable, while anastomosis for segments with ASs between 20 and 30 were feasible and most of needles were penetrable, but exquisite technique was necessary. Arterial target segment with AS >30 was not suitable for anastomosis, and if most of slices in the segment were AS>30, anastomosis target should be changed. Conclusion: In distal bypass to small caliber calcified artery, CT quantitative evaluation using AS clearly discriminated suitable or unsuitable segment for anastomosis. This method was useful to judge feasibility of anastomosis for calcified artery, and suggested that segment with AS under 30 should be chosen as target. Disclosure: Nothing to disclose

Incidental Finding of Liver Metastasis in a Case of Pancreatic Adenocarcinoma

Exocrine cancer of pancreas is the fourth leading cause of death in the United States. Surgical resection is the only curative treatment option. Contrast enhanced multidetector-row computer tomography (MDCT) is the current modality of choice for the detection of distant metastasis in pancreatic cancer. We present a first ever reported case of an incidental liver metastasis in a patient with pancreatic adenocarcinoma. The patient is a 73 year old Caucasian woman who presented with pruritus and painless jaundice. Past medical history was significant for Hypertension, and Type II Diabetes Mellitus but had no significant surgical history. Social history was negative for tobacco, alcohol, and illicit drug use. Family history was noncontributory. Review of system was negative. Liver chemistry revealed Aspartate Aminotransferase 104 U/L, Alanine Aminotransferase 98 U/L, Alkaline Phosphatase 176 U/L, Total Bilirubin 5.7 mg/dL and albumin 3.9 g/dL. Carbohydrate antigen 19-9 was elevated at 278 u/L. Endoscopic retrograde cholangiopancreatogram showed distal common bile duct stricture. Endoscopic ultrasound showed 25 mm pancreatic head mass. Fine needle biopsy of the mass showed adenocarcinoma. Contrast enhanced CT of pancreas and liver and PET /CT scan for staging was negative for distant metastasis. Case was discussed in multidisciplinary team. Patient underwent Whipple procedure. Surgical pathology was positive for poorly differentiated pancreatic ductal adenocarcinoma with perineural invasion. 6/28 regional lymph nodes were positive for malignancy. Lymph nodes involving celiac access and hepatic artery were negative. Intraoperatively liver parenchyma looked grossly abnormal with ultrasonographic findings of early fibrosis. Random wedge biopsy from lateral segment of the liver was positive for 2 mm pancreatic adenocarcinoma.This case clearly suggests that MDCT/PET-CT can miss distant small metastasis. A pilot study done in 2011 by Holzapfel and Reoser-Erken et.al. showed that diffusion weighted magnetic resonance imaging (DW-MRI) is better than MD-CT for detection of small metastatic lesion, with good histopathological correlation. Hence, we need more studies of same kind in future to consider DW-MRI as a part of staging workup in pancreatic lesions that could potentially change the management of pancreatic adenocarcinoma. In addition, it argues for implementation of neo-adjuvant chemotherapy in surgically resectable localized pancreatic adenocarcinoma.2910_A Figure 1. Contrast enhanced CT with pancreatic protocol. Pancreatic head mass (red arrow)2910_B Figure 2. H&E stain, 400 X original magnification.. Wedge Liver biopsy. Histology diagnostic of pancreatic adenocarcinoma.2910_C Figure 3. PET/CT scan. Pancreatic head mass with Fludeoxyglucose (FDG) uptake. (red arrow head)

Imaging in traumatic mandibular fractures.

A fracture of the mandible is a common trauma presentation amongst young males and represents one of the most frequently encountered fractured bones within the viscerocranium. Historically, assault was the dominant contributing factor but now due to the increased number of vehicles used per capita, motor vehicle accidents are the primary cause. Mandibular fractures can be classified anatomically, by dentition, by muscle group and by severity. The fracture may also be closed, open, comminuted, displaced or pathological. It is important that the imaging modality used identifies the classification as this will decide definitive treatment. X-ray projections have typically been used to detect a mandibular fracture, but are limited to an anteroposterior (AP), lateral and oblique view in an unstable trauma patient. These views are inadequate to detail the level of fracture displacement and show poor detail of the condylar region. Computer tomography (CT) is the imaging modality of choice when assessing a traumatic mandibular injury and can demonstrate a 100% sensitivity in detecting a fracture. This is through use of a multidetector-row CT, which reduces motion blur and therefore produces accurate coronal and sagittal reconstructions. Furthermore, reconstructive three-dimensional CT images gained from planar views, allows a better understanding of the spatial relationship of the fracture with other anatomical landmarks. This ensures a better appreciation of the severity and classification of a mandibular fracture, which therefore influences operative planning. Ultrasound is another useful modality in detecting a mandibular fracture when the patient is too unstable to be transferred to a CT scanner. The sensitivity however is less in comparison to a CT series of images and provides limited detail on the fracture pattern. Magnetic resonance imaging demonstrates use in assessing soft tissue injury of the temporomandibular joint but this is unlikely to be of priority when initially assessing a trauma patient.

Plaque Vulnerability in Internal Carotid Arteries with Positive Remodeling

Background: This study aimed to evaluate the efficacy of assessing positive remodeling for predicting future stroke events in the internal carotid artery. We therefore assessed narrowing of the carotid artery lumen using multidetector-row computer tomography (MDCT) angiography and carotid plaque characteristics using black-blood (BB) magnetic resonance (MR). Methods: We retrospectively selected 17 symptomatic and 11 asymptomatic lesions with luminal narrowing >50%. We compared remodeling parameters of luminal stenosis (remodeling ratio, RR/remodeling index, RI) using MDCT and MR intensities of atherosclerotic plaque contents using the BB technique (relative signal intensity, rSI). We also confirmed the validity of the relationship between MR intensity and atherosclerotic plaque contents by histology. The levels of biological markers related to vessel atherosclerosis were measured. Results: Plaque lesions with positive remodeling in carotid arteries were associated with a significantly higher prevalence of stroke compared with plaques with negative remodeling (p < 0.05). Radiologic and histologic analyses determined that plaques with positive remodeling had higher signal intensities (with respect to their lipid-rich content or to hemorrhage) compared with negative remodeling (correlation coefficients: RI and rSI, r = 0.41, p < 0.05; RR and rSI, r = 0.50, p < 0.05). Levels of biological markers, including high-sensitivity C-reactive protein, hemoglobin A1C, total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol, were not useful for predicting stroke events. Conclusions: The results of this study suggest that the combined analysis of RR, RI and rSI could potentially help to predict future stroke events.

Multi-detector row computer tomography findings of fibrous dysplasia in orbital bone

To evaluate the efficacy of multi-detector row CT (MDCT) findings in the diagnosis of fibrous dysplasia (FD) in orbital bone. The MDCT manifestations of 18 cases of FD in orbital bone (6 cases from the 458th hospital of PLA, 12 cases from the Zhongshan ophthalmic center of Sun Yat-Sen university) collected from April 2002 to August 2009 were reviewed. Six cases were confirmed by biopsy, 5 cases were confirmed by operation and postoperative pathology, the remaining 6 cases were confirmed based on typical CT findings. FD in orbital bone could be originated from monostotic single lesion (5 cases), monostotic multiple lesions (1 cases) or polyostotic multiple lesions (12 cases). Twelve lesions were originated in the frontal bone, 5 lesions in the sphenoid, 2 lesions in the ethmoid, 7 lesions in the temporal bone. MDCT is very important in the diagnosis and treatment strategy of FD in orbital bone correctly. It help identify the location and extension of the lesions based on the axial plane, coronal plane and sagittal plane view.

The right accessory hepatic artery; a case report and review of the literature

A rare case of the right accessory hepatic artery was observed during multidetector-row Computer Tomography examination in a 65-year-old Caucasian female with portal vein thrombosis. This artery arose from the common hepatic artery near the celiac trunk and ran behind the hepatic portal vein to the right lobe of the liver. The diameter of the right accessory hepatic artery when compared to the diameter of the proper hepatic and common hepatic arteries corroborated the functional importance of this vessel. In-depth knowledge of not only "standard" anatomy but also of the numerous angiological variants is necessary in clinical practice. The variation shown in our case has very rarely been reported in medical literature.

Quantitative preoperative assessment of vascular involvement in pancreatic carcinoma by multi-detector row computer tomography

Quantitative preoperative assessment of vascular involvement in pancreatic carcinoma by multi-detector row computer tomography

Late enhancement using multidetector row computer tomography: A feasibility study with low dose 80 kV protocol

Aims Detecting stenoses of coronary arteries with multidetector row computer tomography (MDCT) is a well feasible non-invasive method. However, there is still the problem of deciding whether a stenosis is hemodynamically relevant or not. Objective of the present study was to validate the feasibility of a low dose protocol for MDCT using 80 kV for detecting late enhancement. Methods and results Using a Alderson-Rando Phantom evaluation of the effective dose of this LE protocol was performed. Ten patients (six male, four female, mean age 61) with known coronary artery disease and scheduled for a conventional coronary angiogram in our facility were subsequently recruited. All patients underwent CT-angiography (CTA) 1 day prior to magnetic resonance imaging. Five minutes after the application of 100 ml contrast agent for the CTA scan, a low dose late enhancement scan (80 kV, 400 mA s maximum, ECG pulsed scan, 64 mm × 0.6 mm collimation, 0.33 s tube rotation) was performed. Phantom dose measurements showed an effective dose for this protocol of 1.19 mSv (male) and 1.61 mSv (female). Fifty-six percent (5/9) of the patients showed a late enhancement on the MRI scan. Three transmural late enhancements and all four negative findings were correctly identified by CT. This represents a sensitivity of 78% (3/5), specificity of 100% (3/3), NPV of 100% (4/4) and a PPV of 97%. Conclusion We were able to show that the low dose protocol is feasible and, furthermore, preliminary results look promising.

A 60-y-old chylomicronemia patient homozygous for missense mutation (G188E) in the lipoprotein lipase gene showed no accelerated atherosclerosis

Background Familial lipoprotein lipase (LPL) deficiency is a rare autosomal recessive disorder caused by mutations in the LPL gene. Patients with LPL deficiency have chylomicronemia; however, whether they develop accelerated atherosclerosis remains unclear. Methods We investigated clinical and mutational characteristics of a 60-y-old Japanese patient with chylomicronemia. Results The patient's fasting plasma triglyceride levels were > 9.0 mmol/l. In postheparin plasma, one fifth of the normal LPL protein mass was present; however, LPL activity was undetectable. Molecular analysis of the LPL gene showed the patient to be a homozygote of missense mutation replacing glycine with glutamine at codon 188 (G188E), which had been known to produce mutant LPL protein lacking lipolytic activity. Ultrasonographic examination of the patient's carotid and femoral arteries showed no accelerated atherosclerosis. Moreover, 64-slice mechanical multidetector-row computer tomography (MDCT) angiography did not detect any accelerated atherosclerotic lesions in the patient's coronary arteries. The patient had none of the risk factors such as smoking, hypertension, and diabetes. Conclusions Our case suggests that accelerated atherosclerosis may not develop in patients with LPL deficiency, when they have no risk factors.

Multidetector-row computed tomography in the planning of abdominal perforator flaps

An accurate preoperative evaluation of the vascular anatomy of the abdominal wall is extremely valuable in improving the surgical strategy in abdominal perforator flaps. The multidetector-row computer tomography offers thin slice coverage of extended volumes with an extremely high spatial resolution. From October 2003 to December 2004, 66 female patients had breast reconstruction surgery in our department using the deep inferior epigastric artery perforator flap. Our multidetector-row computer tomography studies were performed using a 16-detector-row computer tomography scanner. The image assessment was carried out using the following protocol: we first identified the best three perforators from each side of the abdomen. Then we conducted a three-dimensional reconstruction of the abdomen by identifying exactly where the three best perforators emerged from the rectus abdominis fascia. We then transferred the data obtained from the image to the patient using a coordinate system. In addition, we also placed the dominant perforators in the patient by using a conventional hand-held Doppler. During the operation we compared intra-operative findings, Doppler results and computer tomography outcomes. Neither false positive nor false negative results were found in the computer tomography outcome. Multidetector-row computer tomography provides us with an easy method of interpreting the virtual anatomic dissection in three dimensions. It has high sensitivity and specificity and provides a good quality evaluation of the perforator vessels. This information allows reduction of operating time and safer performance of surgery. The multidetector-row computer tomography is a highly effective tool in the preoperative study of abdominal perforator flaps.

Computed tomography and magnetic resonance imaging for noninvasive coronary angiography and plaque imaging: current and potential future concepts.

Atherothrombosis is a systemic disease of the vessel wall that causes distinct clinical manifestations, depending on the affected circulatory bed and the characteristics of the individual lesions.1 These lesions may be quite heterogeneous.1 Thus, the clinical manifestations of atherothrombosis of the coronary arteries, of the arteries supplying the central nervous system, of the aorta, and of the peripheral circulation can be significantly different. Disruption-prone plaques in the coronary arteries, the so-called “vulnerable plaques,” tend to have a thin fibrous cap (cap thickness ≈65 to 150 μm) and a large lipid core (American Heart Association [AHA] plaque type IV-Va). Acute coronary syndromes often result from disruption of a modestly stenotic vulnerable plaque, not visible by x-ray angiography, which results in a thrombotic complication (AHA plaque type VI). During its evolution, a type Va plaque may also become fibrotic (AHA plaque type Vc) or calcified (AHA plaque type Vb).2,3⇓ In contrast to coronary artery vulnerable plaques characterized by high lipid content and a thin fibrous cap, high-risk plaques of the carotid arteries tend to be fibrotic and severely stenotic.3 ### Imaging of Atherothrombotic Disease Because there is striking heterogeneity in the composition of human atherothrombotic plaques, even within the same individual, reliable noninvasive imaging tools that can detect early atherothrombotic disease in the various regions and characterize the composition of the plaques are clinically desirable.3 Such imaging tools would improve our understanding of the pathophysiological mechanisms underlying atherothrombotic processes and allow us to better risk-stratify the disease. Additionally, such tools may permit optimal tailoring of treatment and allow direct monitoring of the vascular response. Presently, a number of imaging modalities are employed to study atherosclerosis; most identify luminal diameter or stenosis, wall thickness, and plaque volume.3 Two noninvasive imaging modalities, computed tomography and MRI, have been introduced to the study …