Giulia A. Zamboni

Ultrasound-Guided Percutaneous Fine-Needle Aspiration of 545 Focal Pancreatic Lesions

OBJECTIVE The purpose of this study was to assess the accuracy and short-term complication rate of ultrasound-guided fine-needle aspiration cytologic sampling of focal pancreatic lesions. MATERIALS AND METHODS We reviewed 545 consecutive ultrasound-guided fine-needle aspiration cytologic sampling procedures for focal pancreatic lesions from January 2004 through June 2008. The procedures were performed with a 20- or 21-gauge needle. The onsite cytopathologist evaluated the appropriateness of the sample and made a diagnosis. We reviewed the final diagnosis and the radiologic and medical records of all patients for onset of complications during or within 7 days of the procedure. RESULTS The study sample included 262 women and 283 men (mean age, 62 years; range, 25-86 years). The head or uncinate process of the pancreas was the location of 63.0% of the lesions, and 35.2% of the lesions were located in the body or tail of the pancreas. The site of 10 lesions (1.8%) was not specified. Sampling was diagnostic in 509 of the 545 cases (93.4%). Excluding the 36 nondiagnostic samples, ultrasound-guided fine-needle aspiration cytologic sampling had 99.4% sensitivity, 100% specificity, and 99.4% accuracy. In 537 of the 545 cases (98.5%), the procedure was uneventful. In two cases, abdominal fluid was found after the procedure that was not present before the procedure. Six patients experienced postprocedural pain without abnormal findings at subsequent imaging. No major complications occurred. CONCLUSION Ultrasound-guided cytologic sampling is safe and accurate for the diagnosis and planning of management of focal pancreatic lesions. With a cytologist on site, the rate of acquisition of samples adequate for diagnosis is high, reducing the need for patient recall.

Combined Vascular–Excretory Phase MDCT Angiography in the Preoperative Evaluation of Renal Donors

OBJECTIVE The objective of our study was to test a dose reduction protocol that uses combined vascular-excretory phase scanning achieved by split IV contrast injection and compare it with conventional multiphase MDCT angiography (MDCTA) in evaluating potential renal donors. MATERIALS AND METHODS This study is a review of MDCTA examinations of 54 potential renal donors scanned on 16- and 64-MDCT. The IV bolus was split: 50 mL was administered 3 minutes before scanning and a second injection of 70-100 mL was administered at a rate of 4-6 mL/s, with CT angiography started by bolus tracking. The second vascular (venous) phase was acquired 20 seconds later. Two readers reviewed the two phases, assessed vascular and parenchymal anatomy and variants or abnormalities, graded the added value of the venous phase on a 5-point scale, and took attenuation measurements in Hounsfield units. The operative notes of 39 subjects were reviewed as the reference standard for anatomic findings and compared with CT reports. RESULTS All of the relevant anatomy findings, according to the operative notes, were accurately depicted by MDCTA, and all were well recognized on the arterial phase. The arterial phase combined information from the arterial, venous, parenchymal, and excretory phases. The venous phase was inferior to the arterial phase in assessing the renal arteries without additional venous, parenchymal, or excretory phase information. The mean renal artery attenuation was 355 HU in the first phase versus 173 HU in the second phase (p<0.0001). The mean renal vein attenuation was not significantly different between the two phases. The parenchymal system and excretory system were equally well depicted in both vascular phases. CONCLUSION Split-bolus contrast injection and combined vascular-excretory phase scanning are adequate for studying potential renal donors and result in a marked decrease in multiphase scanning and, thus, in radiation dose.

Low voltage CTPA for patients with suspected pulmonary embolism

OBJECTIVE To test a low dose, low voltage protocol for the diagnosis of pulmonary embolism. MATERIALS AND METHODS 50 Patients with clinically suspected pulmonary embolism underwent CTPA with 80kVp and 295mAs (test group) on a 64-row MDCT scanner. These patients were compared to a similar group of 50 patients scanned on the same scanner with the 120kVp protocol with automatic tube current modulation (control group). All patients received 100-110ml of a 370mgI/ml solution at 4.5cm(3)/s. Scans were compared for quantitative imaging parameters (attenuation and standard deviation in the main, right and left pulmonary arteries, in a lobar and segmental pulmonary artery and in the aorta) and for dose parameters (CTDI and DLP), using an unpaired t-test. Phantom measurements were also performed for image quality parameters and radiation dose. RESULTS Mean attenuation was significantly higher in the test group than in the control group in the main pulmonary trunk, in the right pulmonary artery, in the left pulmonary artery, in a lobar and segmental pulmonary artery and in the ascending aorta (all: p≤0.0001). Noise was significantly higher in the test group than in the control group, but contrast to noise ratio was not significantly different between the two protocols. Radiation dose was significantly lower in the test group than in the control group, as measured by CTDI, DLP and effective dose to organs (all: p<0.0001). CONCLUSIONS The use of 80kVp for pulmonary CTA significantly reduces patient radiation exposure, and significantly increases contrast medium attenuation in the pulmonary arteries, with no effect on the diagnostic quality of the exams.

Non invasive cardiac vein mapping: Role of multislice CT coronary angiography

PURPOSE Coronary venous anatomy is of primary importance when implanting a cardiac resynchronization therapy device, besides, the coronary sinus can be differently enlarged depending on chronic heart failure. The aim of this study is to evaluate the usefulness of Coronary CTA in describing the coronary venous tree and in particular the coronary sinus and detecting main venous system variants. MATERIALS AND METHODS 301 consecutive patients (196 ♂, mean age 63.74 years) studied for coronary artery disease with 64 slice Coronary CTA were retrospectively examined. The acquisition protocol was the standard acquisition one used for coronary artery evaluation but the cardiac venous system were visualized. The cardiac venous system was depicted using 3D, MPR, cMPR and MIP post-processing reconstructions on an off-line workstation. For each patient image quality, presence and caliber of the coronary sinus (CS), great cardiac vein (GCV), middle vein (MV), anterior interventricular vein (AIV), lateral cardiac vein (LCV), posterior cardiac vein (PCV), small cardiac vein (SCV) and presence of variant of the normal anatomy were examined and recorded. RESULTS CS, GCV, MV and AIV were visualized in 100% of the cases. The LCV was visualized in 255/301 (84%) patients, the PCV in 248/301 (83%) patients and the SCV in 69/301 (23%) patients. Mean diameter of the CS was 8.7 mm in 276/301 (91.7%) patients without chronic heart failure and 9.93 mm in 25/301 (8.3%) patients with chronic heart failure. CONCLUSIONS Coronary CTA allows non invasive mapping of the cardiac venous system and may represent a useful presurgical tool for biventricular pacemaker devices implantation.

Single-energy low-voltage arterial phase MDCT scanning increases conspicuity of adenocarcinoma of the pancreas.

PURPOSE To test a single-energy low-voltage CT protocol for pancreatic adenocarcinoma. METHODS AND MATERIALS A total of 30 patients with pathology-proven pancreatic adenocarcinoma underwent 64-row MDCT with arterial phase at 80 kV and were compared to a similar group of 30 patients scanned with a 120 kV protocol. Scans were compared for quantitative image parameters (attenuation and standard deviation in the pancreas, tumor, aorta), CTDI and DLP using an unpaired t-test. Image noise values for each protocol (SD of the psoas) were compared using an unpaired t-test. Effective dose was calculated for each protocol. CNR (=conspicuity/SDnoise) and FOM (CNR2/ED) were calculated. The Catphan600 phantom was used to evaluate image non-uniformity, noise, spatial resolution, and low contrast detectability. RESULTS Mean patient weight was 68 kg in the study group and 73 kg in the control group (p=0.0355), while patient diameters at the celiac axis were not significantly different. Mean attenuation was significantly higher at 80 kV in the aorta (517.5±116.4 vs 290.3±76.4 HU) and normal pancreas (154.0±39.95 vs 90.02±19.01 HU) (all p<0.0001), while no significant difference was observed for adenocarcinoma (61.43±35.61 vs 47.45±18.95; p=n.s.). CTDI and DLP were significantly lower at 80 kV (6.00±0.90 mGy vs 10.24±2.93 mGy, and 180.4±35.49 mGy cm vs 383.8±117 mGy cm, respectively; all p<0.0001). Tumor conspicuity (HUpancreas-HUtumor) was significantly higher at 80 kV (94.2±39.3 vs 39.5±22 HU; p<0.0001). Mean image noise was significantly higher at 80kV (28.32±10.06 vs 19.7±7.1HU; p<0.0001). Effective dose was significantly lower at 80 kV (1.984±0.39 vs 5.75±1.75 mSv; p<0.0001). The total DLP for the exam was 1024±31.86 mGy cm for the 80 kV protocol and 1357±62.60 mGy cm for the 120 kV protocol (p<0.0001). Phantoms showed higher non-uniformity, slightly higher noise, slightly lower MTF (50%) and slightly higher percentage contrast for the 80 kV protocol. CONCLUSION Single-source 80 kV pancreatic phase scanning results in higher conspicuity of pancreatic adenocarcinoma and FOM and in significant dose reduction while maintaining acceptable image quality.

Routine use of modified CT Enterography in patients with acute abdominal pain

PURPOSE To evaluate routine use of CT Enterography (CTE) in patients presenting with non-traumatic acute abdominal pain with respect to patient tolerance, imaging of intestinal detail along with conventional abdominal evaluation. MATERIALS AND METHODS Modified CTE was performed in 165 consecutive patients with acute abdominal pain: ingestion, as tolerated, of 900-1200 ml of 2% barium suspension + 5 ml of Gastrografin over 45 min; 150 ml of iv contrast given in two boluses (50 and 100 ml) 3 min apart (split bolus injection protocol). Axial, coronal and sagittal reformats were reviewed by two radiologists and graded on a 5-point scale (5 best) in regard to GI tract luminal opacification and distension and abdominal organ and vascular enhancement. RESULTS In 81 patients the cause of abdominal pain was identified (intestinal in 54 and extraintestinal in 27). Oral contrast reached cecum in 76% of the patients and the small bowel was well distended and opacified (medians=4). Mucosa detail was good (median=3) and there was significant (p<0.0001) correlation between bowel opacification and distension for both jejunum and ileum. A combined nephrographic and excretory phase was achieved (medians 4 and 5, respectively), while the great vessels were well opacified, allowing for vascular evaluation (median=5). The rest of the abdominal structures were well visualized. CONCLUSION Modified CTE is well tolerated by patients with acute non-traumatic abdominal pain, and can be used routinely as a non-invasive examination informative of bowel, vessel and organ pathology in Emergency Department patients.

Multimodality postoperative imaging of liver transplantation

Liver transplantation is the only effective and definitive treatment for patients with end-stage liver disease. The shortage of cadaveric livers has lead to the increasing use of split-liver transplantation and living-donor liver transplantation, but the expansion of the donor pool has increased the risk for postoperative vascular and biliary complications. Early recognition of the imaging appearances of the various postoperative complications of liver transplantation is crucial for both graft and patient survival. This review describes the imaging findings of normal and abnormal transplanted liver parenchyma and of vascular and biliary post-transplantation complications.

Virtual Whipple: preoperative surgical planning with volume-rendered MDCT images to identify arterial variants relevant to the Whipple procedure.

OBJECTIVE The purposes of this study were to combine a thorough understanding of the technical aspects of the Whipple procedure with advanced rendering techniques by introducing a virtual Whipple procedure and to evaluate the utility of this new rendering technique in prediction of the arterial variants that cross the anticipated surgical resection plane. CONCLUSION The virtual Whipple is a novel technique that follows the complex surgical steps in a Whipple procedure. Three-dimensional reconstructed angiographic images are used to identify arterial variants for the surgeon as part of the preoperative radiologic assessment of pancreatic and ampullary tumors.

Focal pancreatic lesions: accuracy and complications of US-guided fine-needle aspiration cytology

Tissue confirmation of the diagnosis is required either for unresectable pancreatic masses or for resectable masses when the diagnosis is uncertain. In this article, we review indications, technique, and clinical results of percutaneous fine-needle aspiration of focal pancreatic lesions.

Blunt diaphragmatic lesions: Imaging findings and pitfalls

Blunt diaphragmatic lesions (BDL) are uncommon in trauma patients, but they should be promptly recognized as a delayed diagnosis increases morbidity and mortality. It is well known that BDL are often overlooked at initial imaging, mainly because of distracting injuries to other organs. Sonography may directly depict BDL only in a minor number of cases. Chest X-ray has low sensitivity in detecting BDL and lesions can be reliably suspected only in case of intra-thoracic herniation of abdominal viscera. Thanks to its wide availability, time-effectiveness and spatial resolution, multi-detector computed tomography (CT) is the imaging modality of choice for diagnosing BDL; several direct and indirect CT signs are associated with BDL. Given its high tissue contrast resolution, magnetic resonance imaging can accurately depict BDL, but its use in an emergency setting is limited because of longer acquisition times and need for patient’s collaboration.