Determining injuries from posterior and flank stab wounds using computed tomography tractography

Unlike anterior stab wounds (SW), in which local exploration may direct management, posterior SW can be challenging to evaluate. Traditional triple contrast computed tomography (CT) imaging is cumbersome and technician-dependent. The present study examines the role of CT tractography as a strategy to manage select patients with back and flank SW. Hemodynamically stable patients with back and flank SW were studied. After resuscitation, Betadine- or Visipaque®-soaked sterile sponges were inserted into each SW for the estimated depth of the wound. Patients underwent abdominal helical CT scanning, including intravenous contrast, as the sole abdominal imaging study. Images were reviewed by an attending radiologist and trauma surgeon. The tractogram was evaluated to determine SW trajectory and injury to intra- or retroperitoneal organs, vascular structures, the diaphragm, and the urinary tract. Complete patient demographics including operative management and injuries were collected. Forty-one patients underwent CT tractography. In 11 patients, tractography detected violation of the intra- or retroperitoneal cavity leading to operative exploration. Injuries detected included: the spleen (two), colon (one), colonic mesentery (one), kidney (kidney), diaphragm (kidney), pneumothorax (seven), hemothorax (two), iliac artery (one), and traumatic abdominal wall hernia (two). In all patients, none had negative CT findings that failed observation. In this series, CT tractography is a safe and effective imaging strategy to evaluate posterior torso SW. It is unknown whether CT tractography is superior to traditional imaging modalities. Other uses for CT tractography may include determining trajectory from missile wounds and tangential penetrating injuries.

Suppression of the auxin response pathway enhances susceptibility to Phytophthora cinnamomi while phosphite-mediated resistance stimulates the auxin signalling pathway

BACKGROUND

Phytophthora cinnamomi is a devastating pathogen worldwide and phosphite (Phi), an analogue of phosphate (Pi) is highly effective in the control of this pathogen. Phi also interferes with Pi starvation responses (PSR), of which auxin signalling is an integral component. In the current study, the involvement of Pi and the auxin signalling pathways in host and Phi-mediated resistance to P. cinnamomi was investigated by screening the Arabidopsis thaliana ecotype Col-0 and several mutants defective in PSR and the auxin response pathway for their susceptibility to this pathogen. The response to Phi treatment was also studied by monitoring its effect on Pi- and the auxin response pathways.

RESULTS

Here we demonstrate that phr1-1 (phosphate starvation response 1), a mutant defective in response to Pi starvation was highly susceptible to P. cinnamomi compared to the parental background Col-0. Furthermore, the analysis of the Arabidopsis tir1-1 (transport inhibitor response 1) mutant, deficient in the auxin-stimulated SCF (Skp1 - Cullin - F-Box) ubiquitination pathway was also highly susceptible to P. cinnamomi and the susceptibility of the mutants rpn10 and pbe1 further supported a role for the 26S proteasome in resistance to P. cinnamomi. The role of auxin was also supported by a significant (P < 0.001) increase in susceptibility of blue lupin (Lupinus angustifolius) to P. cinnamomi following treatment with the inhibitor of auxin transport, TIBA (2,3,5-triiodobenzoic acid). Given the apparent involvement of auxin and PSR signalling in the resistance to P. cinnamomi, the possible involvement of these pathways in Phi mediated resistance was also investigated. Phi (especially at high concentrations) attenuates the response of some Pi starvation inducible genes such as AT4, AtACP5 and AtPT2 in Pi starved plants. However, Phi enhanced the transcript levels of PHR1 and the auxin responsive genes (AUX1, AXR1and AXR2), suppressed the primary root elongation, and increased root hair formation in plants with sufficient Pi.

CONCLUSIONS

The auxin response pathway, particularly auxin sensitivity and transport, plays an important role in resistance to P. cinnamomi in Arabidopsis, and phosphite-mediated resistance may in some part be through its effect on the stimulation of the PSR and auxin response pathways.

CT imaging features of acinar cell carcinoma and its hepatic metastases

OBJECTIVE

To evaluate and describe the computed tomography features of pure acinar cell carcinoma (ACC) and its liver metastases.

METHODS

Thirty patients were evaluated. Two radiologists evaluated imaging findings for each tumor for size, location, internal density, enhancement, tumor calcifications, pancreatic, and common biliary ductal obstructions and metastases.

RESULTS

70 % were male. Fourteen tumors were located in the pancreatic head, 14 in the tail, one in the neck, and one in the uncinate process. Abdominal pain was the most common presenting symptom (93 %), 20 % had pancreatitis and 17 % had obstructive jaundice. The average tumor size was 7 cm, 97 % of tumors were solid, well circumscribed (73 %); isodense to normal pancreatic parenchyma (40 %) on the non-contrast study, hypodense on the arterial (47 %), and hypodense on the portal venous (37 %) phase. 30 % patients had pancreatic ductal dilation, 10 % had pancreatic ductal ingrowth, 6 % had calcifications, and 20 % had central necrosis, and 31 % (5/16) showed biliary ductal dilation. At presentation, 50 % had metastatic adenopathy and 40 % patients had liver metastases, which typically were well circumscribed, hypoattenuating to the hepatic parenchyma on all the phases of contrast enhancement and had a lobulated margin.

CONCLUSION

ACCs of the pancreas often present as large, well circumscribed, solid masses commonly in males. Despite their large size, they may not cause CBD obstruction.

Low molecular weight dextran provides similar optical coherence tomography coronary imaging compared to radiographic contrast media

BACKGROUND

Optical coherence tomography (OCT) coronary imaging requires displacement of red blood cells from the vessel lumen. This is usually accomplished using radiographic contrast. Low molecular weight dextran has low cost and is safe in low volumes. In the present study, we compared dextran with contrast for coronary OCT imaging.

METHODS

Fifty-one vessels in 26 patients were sequentially imaged using manual injection of radiographic contrast (iodixanol) and dextran. OCT images were analyzed at 1 mm intervals to determine the image clarity (defined as a visible lumen border > 270°) and to measure the lumen area and lumen diameter. To correct for the refractive index of dextran, the dextran area measurements were multiplied by 1.117 and the dextran length measurements were multiplied by 1.057.

RESULTS

A total of 3,418 cross-sections (1,709 with contrast and 1,709 with dextran) were analyzed. There were no complications related to OCT imaging or to contrast or dextran administration. Clear image segments were observed in 97.0% vs. 96.7% of the cross-sections obtained with contrast and dextran, respectively (P = 0.45). The mean lumen areas were also similar: 6.69 ± 1.95 mm(2) with iodixanol vs. 7.06 ± 2.06 mm(2) with dextran (correlation coefficient 0.984).

CONCLUSIONS

The image quality and measurements during OCT image acquisition are similar for dextran and contrast. Dextran could be used instead of contrast for OCT imaging, especially in patients in whom contrast load minimization is desired.

Rapid imaging protocol in trauma: a whole-body dual-source CT scan

The purpose of this study is to determine whether a single acquisition whole-body trauma multi-detector CT scan is able to reduce resuscitation time, scan time, and effective radiation dose without compromising diagnostic quality in the setting of polytrauma. Retrospective analysis of 33 trauma patients undergoing single acquisition whole-body CT with injury severity scores of ≥ 16 was compared to 34 patients imaged with a segmented whole-body CT protocol. Time spent in the emergency department, effective radiation dose, image quality, and mortality rates were compared. The single acquisition group spent 53.7 % less time in the emergency department prior to imaging (p=0.0044) and decreased scanning time by 25 %. The protocol yielded a 24.5 % reduction in mean effective radiation dose (24.66 mSv vs. 32.67 mSv, p<0.0001). The image noise was similar in both groups. Standardized mortality ratios were comparable. The single acquisition protocol significantly reduces time spent in the emergency department by allowing faster imaging at a lower radiation dose while maintaining image quality. Other contributors to reduction in radiation dose include use of dual-source CT technology, removal of delayed CT intravenous pyelogram, and arm positioning.

[The value of dual-source dual-energy CT with iodine overlay in the diagnosis of acute necrotizing pancreatitis]

OBJECTIVE

To investigate the clinical value of dual-source computed tomography dual-energy Iodine overlay technique in the imaging diagnosis of acute necrotizing pancreatitis.

METHODS

The imaging data were retrospectively analyzed in 67 cases of acute necrotizing pancreatitis underwent contrast-enhanced dual-source dual-energy CT in portal venous phase. The CT imaging parameters, including the difference of CT value between pancreatic parenchyma and necrotic lesion, contrast-to-noise ratio of pancreatic parenchyma-to-necrosis, area of pancreatic necrosis and score of subjective diagnosis, were measured and assessed on CT images of 80 kV, 140 kV, weighted-average 120 kV as well as Iodine overlay.

RESULTS

The differences of CT value between pancreatic parenchyma and necrosis in the images of 80 kV, 140 kV, weighted-average 120 kV and Iodine overlay were (67.40 +/- 20.82) HU, (42.87 +/- 14.99) HU, (48.69 +/- 15.82) HU, (33.01 +/- 10.26) HU, respectively; contrast-to-noise ratios of pancreatic parenchyma-to-necrosis of each group were 8.36 +/- 3.58, 5.85 +/- 2.65, 7.68 +/- 3.51, 10.60 4.34; area of pancreatic necrosis of each group was (3.78 +/- 2.68) cm2, (3.28 +/- 2.59) cm2, (3.37 +/- 2.46) cm2, (2.42 +/- 1.98) cm2; the score of subjective diagnosis of each group was 3.88 +/- 0.33, 3.31 +/- 0.80, 3.58 +/- 0.66, 2.81 +/- 0.76, respectively. The four indexes in the images of Iodine overlay were significantly different from those of another three groups (P < 0.05). Contrast-to-noise ratio of pancreatic parenchyma-to-necrosis in the images of Iodine overlay was significantly higher than that of another three groups, while the difference of CT value, area of pancreatic necrosis and score of subjective diagnosis were lower. CONCLUSION; Dual-source CT dual-energy Iodine overlay is not helpful to improve subjective judgment in the diagnosis of pancreatic necrosis, but contributes to the display of hypoperfusion area around the necrosis.

Value of noncontrast CT immediately after transarterial chemoembolization of hepatocellular carcinoma with drug-eluting beads

PURPOSE

To retrospectively evaluate the presence and distribution patterns of contrast agent retention in the liver on noncontrast computed tomography (CT) immediately following chemoembolization with drug-eluting beads (DEBs).

MATERIALS AND METHODS

From 2008 to 2010, 95 patients with 224 liver lesions had chemoembolization performed with DEBs and a noncontrast CT examination of the liver performed immediately after embolization. Of these, 85 patients with 193 lesions were included. The postembolization CT scan was reviewed by a diagnostic radiologist, and the presence of contrast agent retention within the lesion was assessed. Varying patterns of contrast agent retention were defined.

RESULTS

Of the 193 lesions included, 146 (76%) retained contrast medium. Aside from some contrast medium in vessels, very little if any contrast medium was seen in the surrounding liver. Various patterns of contrast agent retention were noted within lesions. In a single case, repeat imaging was obtained 6 hours later, which demonstrated washout of contrast agent in a lesion that had retained contrast agent on the postprocedure CT scan. Of significance, 13 additional foci of contrast agent retention were identified on postchemoembolization CT scans that, on retrospective review of preprocedure imaging, represented enhancing lesions not previously identified.

CONCLUSIONS

Noncontrast CT after chemoembolization with DEBs demonstrates contrast agent retention in 76% of cases, without significant contrast medium seen in the adjacent liver parenchyma. The presence or absence of contrast agent retention may prove to be useful in evaluating accurate targeting of a lesion.

Computed tomography imaging of primary lung cancer in mice using a liposomal-iodinated contrast agent

Purpose

To investigate the utility of a liposomal-iodinated nanoparticle contrast agent and computed tomography (CT) imaging for characterization of primary nodules in genetically engineered mouse models of non-small cell lung cancer.

Methods

Primary lung cancers with mutations in K-ras alone (Kras^LA1) or in combination with p53 (LSL-Kras^G12D;p53^FL/FL) were generated. A liposomal-iodine contrast agent containing 120 mg Iodine/mL was administered systemically at a dose of 16 µl/gm body weight. Longitudinal micro-CT imaging with cardio-respiratory gating was performed pre-contrast and at 0 hr, day 3, and day 7 post-contrast administration. CT-derived nodule sizes were used to assess tumor growth. Signal attenuation was measured in individual nodules to study dynamic enhancement of lung nodules.

Results

A good correlation was seen between volume and diameter-based assessment of nodules (R²>0.8) for both lung cancer models. The LSL-Kras^G12D;p53^FL/FL model showed rapid growth as demonstrated by systemically higher volume changes compared to the lung nodules in Kras^LA1 mice (p<0.05). Early phase imaging using the nanoparticle contrast agent enabled visualization of nodule blood supply. Delayed-phase imaging demonstrated significant differential signal enhancement in the lung nodules of LSL-Kras^G12D;p53^FL/FL mice compared to nodules in Kras^LA1 mice (p<0.05) indicating higher uptake and accumulation of the nanoparticle contrast agent in rapidly growing nodules.

Conclusions

The nanoparticle iodinated contrast agent enabled visualization of blood supply to the nodules during the early-phase imaging. Delayed-phase imaging enabled characterization of slow growing and rapidly growing nodules based on signal enhancement. The use of this agent could facilitate early detection and diagnosis of pulmonary lesions as well as have implications on treatment response and monitoring.

[Contrast-induced nephropathy: the VIKISAFE study group statement]

Contrast-induced nephropathy (CIN) has undergone a significant evolution over the years in terms of epidemiology and diagnostic criteria. At present it is defined as CI-AKI (contrast-induced acute kidney injury) and represents a pathologically relevant event for different disciplines. Thus, a multidisciplinary approach is needed to propose and deploy a common strategy to reduce the incidence of CI-AKI. It seems that the use of isoosmolar non-ionic contrast media such as iodixanol can reduce the nephrotoxic effects. However, since these - still controversial - results have been obtained using various diagnostic criteria, they are difficult to compare and pool together. Common criteria are therefore required. The term acute renal failure has been replaced by acute kidney injury (AKI). Thanks to consensus groups such as ADQI (Acute Dialysis Quality Initiative) and AKIN (Acute Kidney Injury Network) and the development of guidelines by KDIGO, the diagnostic criteria for AKI are well defined. Nevertheless, the possibility to utilize new biomarkers of structural kidney damage such as neutrophil gelatinase-associated lipocalin (NGAL) or cystatin C has introduced the concept that AKI may be diagnosed even in the absence of creatinine elevation or decreased urine output. A re-evaluation of the epidemiology of CI-AKI based on new diagnostic criteria is required. In this paper the results of a collaborative multidisciplinary study group are reported from the perspective of different disciplines including nephrology, cardiology, radiology and pharmacology. The findings in a cohort of cardiac patients undergoing imaging procedures using exclusively the isoosmolar non-ionic contrast medium iodixanol are evaluated according to the RIFLE/AKIN criteria.

The accessory spleen: prevalence and imaging findings in 1,735 consecutive patients examined by multidetector computed tomography

OBJECTIVE

To analyze the prevalence and CT findings of accessory spleens in the normal population.

MATERIAL AND METHODS

CT-examinations of 1735 consecutive patients, all examined by triple phase 16-row multidetector computed tomography (MDCT) of the abdomen, were retrospectively analyzed with special emphasis on the presence, location and imaging aspects of accessory spleens.

RESULTS

199 patients showed an accessory spleen (11%). Size of accessory spleens ranged from 3 to 20 mm (mean 10 mm). In 60% the accessory spleen was located at the level of the splenic hilum and in 33% at the level of the lower pole. In 46% the accessory spleen was located medially and in 43% ventrally. 19 patients presented with two (1.1%) and seven patients with three accessory spleens (0.4%), respectively. One patient showed splenosis and one patient showed an enlarged accessory spleen (5 cm) secondary to a splenic apoplexy (i.e. hemorrhagic infarction) of the accessory spleen, caused by torsion.

CONCLUSION

Accessory spleens may be identified by MDCT in about 11% of patients. Familiarity with normal imaging findings and knowledge on differential diagnoses, possible pathologies and potential pitfalls helps to differentiate from other findings in the upper abdomen.

Multislice CT angiography assessment of left coronary artery: correlation between bifurcation angle and dimensions and development of coronary artery disease

PURPOSE

To investigate the relationship between left coronary bifurcation and dimensional changes and development of coronary artery disease using multislice CT angiography.

MATERIALS AND METHODS

30 patients (18 men, 12 women, mean age, 56 years ± 8) suspected of coronary artery disease undergoing 64- and 256-slice CT angiography were included in the study. Left bifurcation angle and left coronary diameter were measured to determine the relationship between angulation and plaque formation and subsequent dimensional changes.

RESULTS

Plaques were present in the left coronary artery in 22 patients with variable angulations and dimensional changes. The mean bifurcation angle between left anterior descending and left circumflex arteries was measured 89.1° ± 13.1° (range, 55.3°, 134.5°) among all patients. The mean bifurcation angle measured in patients with normal and diseased left coronary artery was 75.5° ± 19.8° (range, 60°, 96.1°), and 94° ± 19.7° (range, 55.3°, 134.5°), respectively, with significant difference between these two groups (p=0.02). Similarly, there is a significant difference in the mean diameters of left anterior descending and left circumflex between patients with normal and diseased left coronary artery (p<0.001), which were measured 2.8 ± 0.3mm (range, 2.2, 3.2mm) and 2.1 ± 0.4mm (range, 1.9, 2.9 mm) for the normal left coronary arteries, 4.0 ± 0.8mm (range, 2.5, 6.1mm) and 2.9 ± 0.5mm (range, 1.6, 3.9 mm) for the diseased left coronary arteries, respectively.

CONCLUSION

There is a direct correlation between left bifurcation angle and dimensional changes and formation of plaques. Multislice CT angiography can be used to provide relevant features of left coronary atherosclerosis.

Rapid, simple, and versatile manufacturing of recombinant adeno-associated viral vectors at scale

Adeno-associated viral (AAV) manufacturing at scale continues to hinder the application of AAV technology to gene therapy studies. Although scalable systems based on AAV-adenovirus, AAV-herpesvirus, and AAV-baculovirus hybrids hold promise for clinical applications, they require time-consuming generation of reagents and are not highly suited to intermediate-scale preclinical studies in large animals, in which several combinations of serotype and genome may need to be tested. We observed that during production of many AAV serotypes, large amounts of vector are found in the culture supernatant, a relatively pure source of vector in comparison with cell-derived material. Here we describe a high-yielding, recombinant AAV production process based on polyethylenimine (PEI)-mediated transfection of HEK293 cells and iodixanol gradient centrifugation of concentrated culture supernatant. The entire process can be completed in 1 week and the steps involved are universal for a number of different AAV serotypes. Process conditions have been optimized such that final purified yields are routinely greater than 1 x 10(14) genome copies per run, with capsid protein purity exceeding 90%. Initial experiments with vectors produced by the new process demonstrate equivalent or better transduction both in vitro and in vivo when compared with small-scale, CsCl gradient-purified vectors. In addition, the iodixanol gradient purification process described effectively separates infectious particles from empty capsids, a desirable property for reducing toxicity and unwanted immune responses during preclinical studies.

Angiogenesis of renal cell carcinoma: perfusion CT findings

OBJECTIVE

To observe the perfusion CT findings of renal cell carcinoma (RCC) and prospectively correlate perfusion CT parameters with tumor MVD and VEGF expression.

METHODS

Dynamic contrast-enhanced multislice spiral CT was performed prospectively in 73 cases with histologically proven RCC (65 clear cell, 3 papillary, and 5 chromophobe). Blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface-area product (PS) of RCC and normal renal cortex were measured, respectively. The tumor MVD count and VEGF expression level were determined by immunohistochemistry with specific monoclonal antibodies.

RESULTS

There was significant difference between BF, BV, MTT, and PS of normal renal cortex (454.32 ± 110.90 mL/min/100 g, 23.53 ± 5.71 mL/100 g, 3.62 ± 1.38 s, 63.95 ± 18.85 mL/min/100 g) and RCC (261.96 ± 175.86 mL/min/100 g, 17.17 ± 8.34 mL/100 g, 7.08 ± 3.42 s, 25.07 ± 13.20 mL/min/100 g) (P < 0.01). BF and BV among RCC histologic subtypes were significantly different (P < 0.05), MTT and PS were not (P > 0.05). MVD (42.29 ± 21.00) of RCC is positively correlated with BF, BV, and PS (P < 0.01), not with MTT (P > 0.05). No relationship was found between the expression levels of VEGF and any perfusion CT parameter.

CONCLUSIONS

Perfusion CT is a feasible technique to assess tissue perfusion in patients with RCC. BV, BF, and PS correlate positively with MVD and may reflect angiogenesis of RCC.

Adaptive statistical iterative reconstruction: assessment of image noise and image quality in coronary CT angiography

OBJECTIVE

The purpose of our study was to determine the effect of Adaptive Statistical Iterative Reconstruction (ASIR) on cardiac CT angiography (CTA) signal, noise, and image quality.

MATERIALS AND METHODS

We evaluated 62 consecutive patients at three sites who underwent clinically indicated cardiac CTA using an ASIR-capable 64-MDCT scanner and a low-dose cardiac CTA technique. Studies were reconstructed using filtered back projection (FBP), ASIR-FBP composites using 20-80% ASIR, and 100% ASIR. The signal and noise were measured in the aortic root and each of the four coronary arteries. Two blinded readers graded image quality on a 5-point Likert scale and determined the proportion of interpretable segments. All segments were included for analysis regardless of size.

RESULTS

In comparison with FBP (0% ASIR), the use of 20%, 40%, 60%, 80%, and 100% ASIR resulted in reduced image noise between groups (-7%, -17%, -26%, -35%, and -43%, respectively; p < 0.001) without difference in signal (p = 0.60). There were significant differences between groups (0%, 20%, 40%, 60%, 80%, and 100% ASIR) in the Likert scores (1.5, 2.1, 3.7, 3.8, 2.0, and 1.1, respectively; p < 0.001) and proportion of interpretable segments (88.7%, 89.3%, 90.5%, 90.4%, 88.0%, and 87.3%, respectively; p < 0.001). Reconstruction using 40% and 60% ASIR had the highest Likert scores and largest proportion of interpretable segments. In comparison with FBP, each was associated with higher Likert scores and increased interpretable segments (p < 0.001 for all).

CONCLUSION

ASIR resulted in noise reduction and significantly impacted image quality. When using a low tube current technique, cardiac CTA reconstruction using 40% or 60% ASIR significantly improved image quality and the proportion of interpretable segments compared with FBP reconstruction.

Congenital nasolacrimal duct mucocele--a case report

Congenital nasolacrimal duct mucocele (CNDM) is a very rare condition in newborns. Prolapse or expansion of the mucocele into the nose may lead to respiratory distress and difficulty in feeding. The triad of cystic medial canthal mass, dilatation of the nasolacrimal duct and a contiguous sub-mucosal nasal mass on computed tomography (CT) is indicative in the diagnosis of CNDM. The case of a five-week-old girl with infected CNDM is described. The authors aim to emphasize the very rare incidence of CNDM in Polish newborns, delayed diagnosis in the case described and the paramount importance of CT of the head for the correct diagnosis and treatment.

Posterior reversible encephalopathy syndrome occurring after uterine artery embolization for uterine myoma

This case report describes posterior reversible encephalopathy syndrome (PRES) occurring after uterine artery embolization (UAE) for uterine myoma. This is the first report of PRES occurring after uterine vascular radiologic intervention. The mechanism by which UAE induced PRES is unclear.

The use of dynamic volumetric CT angiography (DV-CTA) for the characterization of endoleaks following fenestrated endovascular aortic aneurysm repair (f-EVAR)

Accurate endoleak classification is essential following fenestrated endovascular aneurysm repair (f-EVAR). Both endoleak type and exact source of endoleak have implications upon the urgency and complexity of future management strategies. Herein we report on a patient with a documented endoleak post-f-EVAR, in which the source of blood flow into the aneurysm sac could not be determined using conventional computed tomographic angiography. Consequently, dynamic volumetric computed tomographic angiography (DV-CTA) was employed, which clearly illustrated the site of origin of the endoleak. DV-CTA enables accurate endoleak characterization following f-EVAR, with excellent conspicuity of the source of blood flow into the aneurysm sac.

[The non-occlusive modality of optical coherence tomography image acquisition: a new concept for wide clinical application]

Optical coherence tomography (OCT) is a novel intravascular imaging modality, based on infrared light emission. This technique enables a high resolution arterial wall imaging but requires a complicated image acquisition process. The aim of this review is to describe a new non-occlusive modality of OCT acquisition, developed by our group, which does not require balloon occlusion of target artery, and to point out its safety and efficacy, describing the required steps to generate good quality images. In the article we referred to previous experimental studies conducted in animals to identify the solution to be used to acquire images of good quality with least adverse effects. Iodixanol 320 was found to have the best image quality/side-effect ratio and enabled the study of long arterial segments. The same solution was then tested in humans, on a large patient population, having either acute coronary syndromes or stable angina. OCT imaging by means of this non-occlusive modality proved to be successful in the vast majority of patients, enabling in over 95% of cases the comparison of the lesion with a reference site. Vessel interrogation was found to be fast and safe. The nonocclusive modality of OCT image acquisition is safe and effective and promises to simplify the complex current occlusive technique, leading to a marked reduction of procedural time.