Geologists and engineers recently have adopted computerised X-ray microtomography (microCT), a radiological imaging technique, for geological and petrophysical applications such as the assessment of sediment characteristics, CT-measurement of compressibility and compaction, multiphase flow studies, measurement of bulk density and moisture content, and of porosity and permeability. This study focuses on ...

During the past decade, unenhanced computed tomography (CT) has become the standard of reference in the detection of urinary calculi owing to its high sensitivity (>95%) and specificity (>98%) in this setting. Numerous diseases may manifest as acute flank pain and mimic urolithiasis. Up to one-third of unenhanced CT examinations ...

The present dental reconstructed computed tomography (CT) images consist of continuously piled-up axial CT images that are perpendicular to the axial CT plane. In the mandibular posterior region, the angles of designed implants frequently differ from the angles perpendicular to the axial CT plane and the measurement of mandibular height ...

The objective is to evaluate the appearance of phleboliths and distal ureteral stones by determining their roundness and presence of central lucency on thin-slice CT. Seventy-seven patients with pelvic radioopacities at unenhanced CT were selected. Those patients consequently underwent thin-slice CT with 1-mm collimation, a FOV of 10 cm, a ...

The objective of the study was to determine the value of spiral computerized tomography (CT) in detecting urolithiasis in pediatric patients and compare its efficacy with ultrasound (US). Twenty-nine infants aged between 2 to 94 months with clinical presentation suggestive of urolithiasis and a negative or indeterminate plain film were ...

OBJECTIVES: To determine the chemical composition of pure and mixed urinary calculi by multislice helical computed tomography (CT) in an in vitro setting. CT is becoming the preferred radiologic examination in diagnosis and management of calculus disease. The management of calculus disease can be facilitated by ascertaining the stone composition. ...

PURPOSE: To determine whether magnetic resonance urography (MRU), obtained before helical computed tomography (CT) in patients with acute renal colic, can help delimit the obstructed area to be subsequently examined by a targeted CT scan, thus reducing the dose of radiation. MATERIALS AND METHODS: Patients (51) with symptoms of acute ...

MR imaging provides a comprehensive method for noninvasive evaluation of renal donor anatomy. Although multidetector helical CT can provide similar information, MR imaging has the advantage of avoiding exposure to ionizing radiation and potentially nephrotoxic contrast material. These are important considerations in screening a generally healthy donor population. MR imaging ...

Imaging investigations play a vital role in the management of patients with kidney stones. The techniques available include plain x-ray of the abdomen, ultrasound scan, intravenous urogram, computed tomography (CT) and magnetic resonance imaging, amongst others. All of these techniques have their own individual roles to play and also have ...

Obscure gastrointestinal (GI) bleeding is a common but frustrating disease for clinicians because of its elusive nature despite extensive work-up. We evaluate the role of helical computed tomography (CT) imaging using rapid infusion of intravenous contrast and water as oral contrast in the work-up of patients who are actively bleeding. ...

This is a report on a case of arteriovenous malformation of the jejunum, which is a relatively rare occurrence that can be detected by helical computed tomography (helical CT). The patient was a 63-year-old man who was admitted to our hospital because of a tarry stool. He developed hypotension as ...

PURPOSE: To determine the sensitivity of computed tomography (CT) scout view in detecting ureteral stones and whether CT scout radiography can replace plain film in the evaluation of patients with acute urinary tract colic. MATERIAL AND METHODS: Between January 2000 and 2002, 110 patients with ureterolithiasis were prospectively evaluated for ...

The purpose of this study was to evaluate helical CT angiography in the assessment of occlusive arterial disease of abdominal aorta and the lower extremities. Sixteen patients underwent both transcatheter angiography and helical CT. Helical CT was inconclusive in 6.2% of segments whereas angiography was inconclusive in 5%. The overall ...

The causes of the image artifacts in a 4-slice helical computed tomography have been discussed as follows: (1) changeover in pairs of data used in z interpolation, (2) sampling interval in z, and (3) the cone angle. This study analyzes the first two causes of the artifact and describes how ...

The aim of this study was to evaluate the efficacy of helical CT using a combination of CT-attenuation values and visual assessment of stone density as well as discriminant linear analysis to predict the chemical composition of urinary calculi. One hundred human urinary calculi were obtained from a stone-analysis laboratory ...

A generalization of the quasi-exact algorithms of Kudo et al (2000 IEEE Trans. Med. Imaging 19 902-21) is developed that allows for data acquisition in a 'practical' frame for clinical diagnostic helical, cone-beam computed tomography (CT). The algorithm is investigated using data that model nonlinear partial volume averaging. This investigation ...

In this paper, the sampling and aliasing consequences of employing a quarter-detector-offset (QDO) in helical computed tomography (CT) are analyzed. QDO is often used in conventional CT to reduce in-plane aliasing by eliminating data redundancies to improve radial sampling. In helical CT, these same redundancies are exploited to improve longitudinal ...

BACKGROUND: We retrospectively compared the accuracy of somatostatin receptor scintigraphy (SRS) with that of helical computed tomography (CT) in the detection and localization of primary and metastatic neuroendocrine tumors. METHODS: A medical record search identified 27 patients with known or clinically suspected neuroendocrine tumors who underwent helical CT and SRS ...

Acute flank pain is a common problem in emergency medicine. The most frequent cause is urolithiasis, but many other entities can cause the same clinical presentation. In many institutions unenhanced computed tomography (CT) of the abdomen is used in this setting. One of the major advantages of unenhanced CT is ...

OBJECTIVES: To present a simple method to assist in distinguishing stents or nephrostomy tubes from urinary tract stones. Non-contrast computed tomography (CT) is now routinely used for the diagnosis and follow-up of urinary tract stones. When stents or nephrostomy tubes are in place, it may be difficult to differentiate the ...

OBJECTIVES: To assess the ability of helical computed tomography (CT) to differentiate regions of known mineral composition in typical, heterogeneous urinary stones. Interest is substantial in the urologic community in using radiologic imaging to determine accurately the composition of urinary calculi. Recent advances in CT make this a viable prospect, ...

PURPOSE: To assess helical computed tomography (CT) with contrast material administered intravenously, orally, and rectally (triple contrast helical CT)) in the prospective evaluation of stable patients with abdominal gunshot wounds in whom there is no clinical indication for immediate exploratory laparotomy. MATERIALS AND METHODS: The study was conducted for 19 ...

The aim of this study was to assess the usefulness of combined direct and indirect signs on intravenous urography (IVU) and unenhanced helical computed tomography (UHCT) for the diagnosis of ureteral stones in emergency patients with acute flank pain. During an 8-month period, 82 emergency patients with acute flank pain ...

OBJECTIVE: Unenhanced helical CT is the imaging method of choice when evaluating patients with acute flank pain and suspected ureterolithiasis. In addition to directly identifying stones in the lumen of the ureter, CT secondary signs of obstruction such as ureteral dilatation are frequently present and can be helpful in establishing ...

PURPOSE OF REVIEW: Stone disease continues to plague humankind. Recent innovations in minimally invasive surgery, however, have decreased morbidity for the treatment of lithiasis, once only amenable to open surgical techniques. These advances in stone management have also been paralleled in the radiographic armamentarium. Herein, we describe the evolution of ...

OBJECTIVE: The purpose of this study was to assess the value of preoperative helical CT for the detection of adhesion of the gallbladder or surrounding peritoneum. SUBJECTS AND METHODS: Dynamic-enhanced helical CT of the abdomen was obtained before laparoscopic cholecystectomy in 47 patients. Images were reconstructed with a 5-mm interval. ...

The goal of this paper is to study Cone-beam CT scanning along a helix of variable pitch. First the rationale and applications in medical imaging of variable pitch CT reconstruction are explained. Then formulas for the minimum detection window are derived. The main part of the paper proves a necessary ...

OBJECTIVE: The fluoroscopic image from the second plan (oblique) tube of an upper ureteral stone close to the crista iliaca may be superimposed on the pelvic bones during SWL using the Siemens Lithostar with the patient in the prone position. This creates difficulty in imaging and targeting of the stone ...

<b>Objectives: </b> To compare the findings of helical com-puted tomography (CT) angiography and the intraopera-tive findings in voluntary kidney donors. <b> Methods: </b> This was a prospective study evaluating 28 voluntary kidney donors from January 2001 to December 2002 who underwent a preoperative CT angiography with a 20 minute intravenous ...

This article outlines the use of multislice CT of the brain with regard to routine scanning, as well as high speed and/or high resolution multiplanar reconstructions. It describes in detail the recent developments in cerebral perfusion scanning and CT arteriography. It will also outline the approach of the University Hospital ...

The aim of this study is to quantify the effects of helical CT acquisitions parameters on the magnitude of three-dimensional stair-step artefacts, visualization of renal ostium and morphologies of suprarenal stents observed using virtual intravascular endoscopy. This was performed in a phantom of the human abdominal aorta with a stent ...

Currently, cone-beam computerized tomography (CT) and micro-CT scanners are under rapid development for major biomedical applications. Half-scan cone-beam image reconstruction algorithms assume only part of a scanning turn, and are advantageous in terms of temporal resolution and image artifacts. While the existing half-scan cone-beam algorithms are in the Feldkamp framework, ...

The management of the patients with acute abdomen syndrome requires an accurate and rapid diagnostic. Spiral CT is the investigation of choice in these cases because it is rapid, cost-effective and provides a global perspective of abdominal structures. Also, helical CT offers the possibility to obtain thinner contiguous images and ...

BACKGROUND AND PURPOSE: Patients with renal colic are frequently evaluated in the emergency room with a helical noncontrast CT scan (NCCT) as the primary imaging modality. Treatment decisions are often based on the size of the ureteral stone(s). We wished to assess the accuracy of NCCT in estimating ureteral stone ...

AIM: The purpose of this study was to determine the incidence of secondary signs associated with ureteral stones on unenhanced helical computed tomography (CT) of patients with acute renal colic, and to correlate these with patient management and outcome. MATERIALS AND METHODS: One hundred and ten patients with ureterolithiasis were ...

A 38-year-old woman with a duplicated right collecting system and a history of right upper-pole heminephrectomy was referred for persistent dysuria and right lower-quadrant abdominal discomfort. Imaging identified a remnant ureter and a ureterocele filled with what appeared to be a large homogenous stone. At cystoscopy, the ureterocele was incised ...

BACKGROUND AND PURPOSE: The practice of utilizing helical CT to evaluate patients suspected of renal colic is increasing. Little is known about the accuracy of CT in estimating stone size or the utility of an accompanying plain abdominal radiograph (KUB film). The purpose of our study was to compare ureteral ...

BACKGROUND AND PURPOSE: To compare urinary stone size as measured by abdominal plain radiography (AXR) with stone size as measured by noncontrast three-dimensional spiral CT in patients with acute renal colic. PATIENTS AND METHODS: Patients presenting to the emergency room of a single institution with urinary stones that were visible ...

We report on the diagnosis and minimally invasive management of Fraley's syndrome using helical CT with volume-rendering techniques in an 18-year-old patient. Three-dimensional images were generated rapidly and allowed safe planning and execution of a laser infundibulotomy of the upper-pole calix. After 24 months of follow-up, the patient remains pain ...

Introduction of helical CT started a new era in the diagnosis of PE. It is noninvasive and readily available. Developments in helical CT technology (particularly introduction of multidetector scanners) improved image quality by decreasing the scanning time and slice thickness. With the addition of indirect CT venography to CT pulmonary ...

In x-ray micro-CT applications, it is useful to increase the field of view by offsetting a two-dimensional (2D) detector array. In this technical note, we briefly review the methods for image reconstruction with an asymmetric 2D detector array, elaborate on the use of an associated weighting scheme in the case ...

OBJECTIVE: This study aimed to determine the value of CT, endoscopic sonography, and a combined protocol for preoperative detection of insulinomas. MATERIALS AND METHODS: All patients treated in our institution for surgically proven insulinoma between 1987 and 2000 were retrospectively reviewed. Thirty patients with 32 pancreatic insulinomas underwent preoperative CT ...

The purpose of this study is to compare triphasic helical CT and fast MRI with respect to detection, characterization and staging of suspected renal masses. To achieve this triphasic helical CT (plain, corticonephrographic and tubulonephrographic phase) and MRI with fast T(1) weighted and T(2) weighted sequences were performed in 29 ...

The origin of the right inferior phrenic artery (RIPA) was assessed in 216 patients using arterial-phase, contrast-enhanced multidetector row helical computed tomography (CT) and that of 26 patients was confirmed by angiography. One hundred and eighty patients showed the origin of the RIPA in aorta, the celiac artery, the right ...

BACKGROUND: We reviewed the computed tomographic (CT) findings of afferent loop obstruction and assessed the value of helical CT in determining the underlying cause. METHODS: Helical CT scans of 18 patients (12 men and six women; age range = 35-67, mean age = 50 years) with afferent loop obstruction were ...

CT is a robust, rapid means of evaluation for a wide spectrum of urologic disorders. The evaluation of renal trauma, urologic malignancy, urolithiasis, and vascular anatomy is well suited to CT techniques. Subtle adjustments in the technical parameters and timing of the study, however, can optimize the evaluation based on ...

PURPOSE: To compare the effectiveness of thin-section helical CT and MR imaging with gadolinium-enhanced dynamic technique and MR cholangiopancreatography (MRCP) in the examination of patients with intraductal papillary mucinous tumors. MATERIAL AND METHODS: Helical CT, dynamic MR imaging, and MRCP of 25 intraductal papillary mucinous tumors were compared with ERCP ...

PURPOSE: Prospective non-enhanced computerized tomography (CT) was performed for patients presenting with renal colic and showing negative or equivocal results on plain x-ray of the kidneys, ureters and bladder (KUB) as well as ultrasonography (US) to evaluate the usefulness of plain CT. We also evaluated the clinical characteristics of urinary ...

This brief report describes the case of a 20-year-old man who was stabbed in the left flank. He underwent triple contrast helical CT of the abdomen and pelvis that showed a hyperdense focus in the area of the stab wound. This structure was a chip fracture of pelvis, but was ...

PURPOSE: To evaluate the feasibility of helical computed tomography (CT) as an imaging modality for depicting active colonic hemorrhage in a swine model. MATERIALS AND METHODS: Controlled extravasation of contrast material-enhanced blood (CEB) from 140 to 180 HU and at varying rates (0.3-1.0 mL/min) was performed during a 30-second period ...