“Beyond saving lives”: Current perspectives of interventional radiology in trauma

Interventional radiology (IR) has become an integral part in the management of traumatic injuries. There is an ever-increasing role of IR in traumatic injuries of solid abdominal organs, pelvic and peripheral arteries to control active bleeding by therapeutic embolization or vascular reconstruction using stent grafts. Traditionally, these endovascular treatments have been offered to hemodynamically stable patients. However, in recent times endovascular approach has become preferable to surgery even in hemodynamically unstable patients with injury of surgically difficult-to-access sites. With shifting trends towards non operative management coupled with availability of the current state-of-the-art equipments, hardware and technical expertise, IR has gained an impeccable role in trauma management. However, due to lack of awareness and widespread acceptance, IR continues to remain an ocean of unexplored potentialities.

Gd-EOB-DTPA based magnetic resonance imaging for predicting liver response to portal vein embolization

AIM

To evaluate the correlation between degree of kinetic growth (kGR) of the liver following portal vein embolization (PVE) liver and the enhancement of the during the hepatobiliary phase of contrast administration and to evaluate if the enhancement can be used to predict response to PVE prior to the procedure.

METHODS

Seventeen patients were consented for the prospective study. All patients had an MR of the abdomen with Gd-EOB-DTPA. Fourteen patients underwent PVE. The correlation between the kGR of the liver and the degree of enhancement was evaluated with linear regression (strong assumptions) and Spearman’s correlation test (rank based, no assumptions). The correlation was examined for the whole liver, segments I, VIII, VII, VI, V, IV, right liver and left liver.

RESULTS

There was no correlation between the degree of enhancement during the hepatobiliary phase and kGR for any segment, lobe of the liver or whole liver (P = 0.19 to 0.91 by Spearman’s correlation test).

CONCLUSION

The relative enhancement of the liver during the hepatobiliary phase with Gd-EOB-DTPA cannot be used to predict the liver response to PVE.

C-reactive protein and radiographic findings of lower respiratory tract infection in infants

AIM

To evaluate the association between C-reactive protein (CRP) and radiological evidence of lower respiratory tract infection (LRTI) in infants.

METHODS

All patients aged less than 4 years who presented with suspected lower respiratory tract infection, who received a peri-presentation chest radiograph and CRP blood measurement over an 18-mo period were included in the study. Age, gender, source of referral, CRP, white cell count, neutrophil count along with the patients’ symptoms and radiologist’s report were recorded.

RESULTS

Three hundred and eleven patients met the inclusion criteria. Abnormal chest radiographs were more common in patients with elevated CRP levels (P < 0.01). Radiologic signs of LRTI were identified in 73.7% of chest radiographs when a patient had a CRP level between 50-99 mg/L. CRP levels were a better predictor of positive chest radiograph findings for those aged greater than I year compared to those 1 year or less.

CONCLUSION

CRP may be used in patients with suspected LRTI diagnosis to select those who are likely to have positive findings on chest radiograph, thus reducing unnecessary chest radiographs.

Computed tomography-guided catheter drainage with urokinase and ozone in management of empyema

AIM

To retrospectively compare the outcomes of catheter drainage, urokinase and ozone in management of empyema.

METHODS

Retrospective study included 209 patients (111 males and 98 females; age range 19 to 72 years) who were diagnosed with empyema. The patients were divided into 3 groups based on the therapy instituted: catheter drainage only (group I); catheter drainage and urokinase (group II); catheter drainage, urokinase and ozone (group III). Drainage was considered successful if empyema was resolved with closure of cavity, clinical symptoms were resolved, and need for any further surgical procedure was avoided. Success rate, length of stay (LOS), need for further surgery and hospital costs were compared between the three groups using the Kruskall-Wallis nonparametric test, with P < 0.05 considered significant.

RESULTS

Of the 209 patients with empyema, all catheters were placed successfully under CT guidance. Sixty-three patients were treated with catheters alone (group I), 64 with catheters and urokinase (group II), and 82 with catheters, urokinase and ozone (group III). Group I, group II and group III had success rates of 62%, 83% and 95% respectively (P < 0.05). Group I and group II had statistically longer LOS (P < 0.05) and higher hospital costs (P < 0.05) compared to group III. There were statistically significant differences between the three groups when comparing patients who converted into further surgery.

CONCLUSION

The combination of chest tube drainage, urokinase and ozone is a safe and effective therapeutic modality in thoracic empyema.

New era of electronic brachytherapy

Traditional brachytherapy refers to the placement of radioactive sources on or inside the cancer tissues. Based on the type of sources, brachytherapy can be classified as radionuclide and electronic brachytherapy. Electronic brachytherapy uses miniaturized X-ray sources instead of radionuclides to deliver high doses of radiation. The advantages of electronic brachytherapy include low dose to organs at risk, reduced dose to treating staff, no leakage radiation in off state, less shielding, and no radioactive waste. Most of these systems operate between 50 and 100 kVp and are widely used in the treatment of skin cancer. Intrabeam, Xoft and Papillon systems are also used in the treatment of intra-operative radiotherapy to breast in addition to other treatment sites. The rapid fall-off in the dose due to its low energy is a highly desirable property in brachytherapy and results in a reduced dose to the surrounding normal tissues compared to the Ir-192 source. The Xoft Axxent brachytherapy system uses a 2.25 mm miniaturized X-ray tube and the source almost mimics the high dose rate Ir-192 source in terms of dose rate and it is the only electronic brachytherapy system specifically used in the treatment of cervical cancers. One of the limiting factors that impede the use of electronic brachytherapy for interstitial application is the source dimension. However, it is highly anticipated that the design of miniaturized X-ray tube closer to the dimension of an Ir-192 wire is not too far away, and the new era of electronic brachytherapy has just begun.

Segmentations of the cartilaginous skeletons of chondrichthyan fishes by the use of state-of-the-art computed tomography

AIM

To apply dual-source multidetector computed tomography (DSCT) scanning technology in conjunction with computationally assisted segmentation in order to explore and document skeletal variation that has occurred over the course of evolution.

METHODS

We examined 4 divergent species of elasmobranchs with high-resolution 3^rd generation DSCT. The formalin prepared species examined were: Aptychotrema vincentiana, Mitsukurina owstoni, Negaprion brevirostris and Dactylobatus armatus.

RESULTS

All three structures of the hyoid arch (hyomandibular, ceratohyal, and basihyal) were clearly visible whereas in the two batoids, the hyomandibular was the prominent feature, the ceratohyal was not visible and the basihyal was more reduced and closer to the gill arches. The general shape of the puboischiadic bar, or pelvic girdle, illustrated a closer relationship between the two sharks and the two batoids than between the two groups.

CONCLUSION

In exquisite detail, DSCT imaging revealed important morphological variations in various common structures in the four elasmobranch specimens studied, providing insights into their evolutionary diversification.

Three-dimensional radiation dosimetry using polymer gel and solid radiochromic polymer: From basics to clinical applications

Accurate dose measurement tools are needed to evaluate the radiation dose delivered to patients by using modern and sophisticated radiation therapy techniques. However, the adequate tools which enable us to directly measure the dose distributions in three-dimensional (3D) space are not commonly available. One such 3D dose measurement device is the polymer-based dosimeter, which changes the material property in response to radiation. These are available in the gel form as polymer gel dosimeter (PGD) and ferrous gel dosimeter (FGD) and in the solid form as solid plastic dosimeter (SPD). Those are made of a continuous uniform medium which polymerizes upon irradiation. Hence, the intrinsic spatial resolution of those dosimeters is very high, and it is only limited by the method by which one converts the dose information recorded by the medium to the absorbed dose. The current standard methods of the dose quantification are magnetic resonance imaging, optical computed tomography, and X-ray computed tomography. In particular, magnetic resonance imaging is well established as a method for obtaining clinically relevant dosimetric data by PGD and FGD. Despite the likely possibility of doing 3D dosimetry by PGD, FGD or SPD, the tools are still lacking wider usages for clinical applications. In this review article, we summarize the current status of PGD, FGD, and SPD and discuss the issue faced by these for wider acceptance in radiation oncology clinic and propose some directions for future development.

Reporting rotator cuff tears on magnetic resonance arthrography using the Snyder's arthroscopic classification

AIM

To determine diagnostic performance of magnetic resonance arthrography (MRA) in evaluating rotator cuff tears (RCTs) using Snyder's classification for reporting.

METHODS

One hundred and twenty-six patients (64 males, 62 females; median age 55 years) underwent shoulder MRA and arthroscopy, which represented our reference standard. Surgical arthroscopic reports were reviewed and the reported Snyder's classification was recorded. MRA examinations were evaluated by two independent radiologists (14 and 5 years' experience) using Snyder's classification system, blinded to arthroscopy. Agreement between arthroscopy and MRA on partial- and full-thickness tears was calculated, first regardless of their extent. Then, analysis took into account also the extent of the tear. Interobserver agreement was also calculated the quadratically-weighted Cohen kappa statistics.

RESULTS

On arthroscopy, 71/126 patients (56%) had a full-thickness RCT. The remaining 55/126 patients (44%) had a partial-thickness RCT. Regardless of tear extent, out of 71 patients with arthroscopically-confirmed full-thickness RCTs, 66 (93%) were correctly scored by both readers. All 55 patients with arthroscopic diagnosis of partial-thickness RCT were correctly assigned as having a partial-thickness RCT at MRA by both readers. Interobserver reproducibility analysis showed total agreement between the two readers in distinguishing partial-thickness from full-thickness RCTs, regardless of tear extent (k = 1.000). With regard to tear extent, in patients in whom a complete tear was correctly diagnosed, correct tear extent was detected in 61/66 cases (92%); in the remaining 5/66 cases (8%), tear extent was underestimated. Agreement was k = 0.955. Interobserver agreement was total (k = 1.000).

CONCLUSION

MRA shows high diagnostic accuracy and reproducibility in evaluating RCTs using the Snyder's classification for reporting. Snyder's classification may be adopted for routine reporting of MRA.

Complementary roles of interventional radiology and therapeutic endoscopy in gastroenterology

Acute upper and lower gastrointestinal bleeding, enteral feeding, cecostomy tubes and luminal strictures are some of the common reasons for gastroenterology service. While surgery was initially considered the main treatment modality, the advent of both therapeutic endoscopy and interventional radiology have resulted in the paradigm shift in the management of these conditions. In this paper, we discuss the patient’s work up, indications, and complementary roles of endoscopic and angiographic management in the settings of gastrointestinal bleeding, enteral feeding, cecostomy tube placement and luminal strictures. These conditions often require multidisciplinary approaches involving a team of interventional radiologists, gastroenterologists and surgeons. Further, the authors also aim to describe how the fields of interventional radiology and gastrointestinal endoscopy are overlapping and complementary in the management of these complex conditions.

Computed tomography pulmonary angiography using a 20% reduction in contrast medium dose delivered in a multiphasic injection

AIM

To evaluate the feasibility of reducing the dose of iodinated contrast agent in computed tomography pulmonary angiography (CTPA).

METHODS

One hundred and twenty-seven patients clinically suspected of having pulmonary embolism underwent spiral CTPA, out of whom fifty-seven received 75 mL and the remaining seventy a lower dose of 60 mL of contrast agent. Both doses were administered in a multiphasic injection. A minimum opacification threshold of 250 Hounsfield units (HU) in the main pulmonary artery is used for assessing the technical adequacy of the scans.

RESULTS

Mean opacification was found to be positively correlated to patient age (Pearson’s correlation 0.4255, P < 0.0001) and independent of gender (male:female, 425.6 vs 450.4, P = 0.34). When age is accounted for, the study and control groups did not differ significantly in their mean opacification in the main (436.8 vs 437.9, P = 0.48), left (416.6 vs 419.8, P = 0.45) or the right pulmonary arteries (417.3 vs 423.5, P = 0.40). The number of sub-optimally opacified scans (the mean opacification in the main pulmonary artery < 250 HU) did not differ significantly between the study and control groups (7 vs 10).

CONCLUSION

A lower dose of iodine contrast at 60 mL can be feasibly used in CTPA without resulting in a higher number of sub-optimally opacified scans.

Multimodality imaging using proton magnetic resonance spectroscopic imaging and 18F-fluorodeoxyglucose-positron emission tomography in local prostate cancer

AIM

To assess the relationship using multimodality imaging between intermediary citrate/choline metabolism as seen on proton magnetic resonance spectroscopic imaging (¹H-MRSI) and glycolysis as observed on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) in prostate cancer (PCa) patients.

METHODS

The study included 22 patients with local PCa who were referred for endorectal magnetic resonance imaging/¹H-MRSI (April 2002 to July 2007) and ¹⁸F-FDG-PET/CT and then underwent prostatectomy as primary or salvage treatment. Whole-mount step-section pathology was used as the standard of reference. We assessed the relationships between PET parameters [standardized uptake value (SUVmax and SUVmean)] and MRSI parameters [choline + creatine/citrate (CC/Cmax and CC/Cmean) and total number of suspicious voxels] using spearman’s rank correlation, and the relationships of PET and ¹H-MRSI index lesion parameters to surgical Gleason score.

RESULTS

Abnormal intermediary metabolism on ¹H-MRSI was present in 21/22 patients, while abnormal glycolysis on ¹⁸F-FDG-PET/CT was detected in only 3/22 patients. Specifically, index tumor localization rates were 0.95 (95%CI: 0.77-1.00) for ¹H-MRSI and 0.14 (95%CI: 0.03-0.35) for ¹⁸F-FDG-PET/CT. Spearman rank correlations indicated little relationship (ρ = -0.36-0.28) between ¹H-MRSI parameters and ¹⁸F-FDG-PET/CT parameters. Both the total number of suspicious voxels (ρ = 0.55, P = 0.0099) and the SUVmax (ρ = 0.46, P = 0.0366) correlated weakly with the Gleason score. No significant relationship was found between the CC/Cmax, CC/Cmean or SUVmean and the Gleason score (P = 0.15-0.79).

CONCLUSION

The concentration of intermediary metabolites detected by ¹H MRSI and glycolytic flux measured ¹⁸F-FDG PET show little correlation. Furthermore, only few tumors were FDG avid on PET, possibly because increased glycolysis represents a late and rather ominous event in the progression of PCa.

Laser ablation of liver tumors: An ancillary technique, or an alternative to radiofrequency and microwave?

Radiofrequency ablation (RFA) is currently the most popular and used ablation modality for the treatment of non surgical patients with primary and secondary liver tumors, but in the last years microwave ablation (MWA) is being technically improved and widely rediscovered for clinical use. Laser thermal ablation (LTA) is by far less investigated and used than RFA and MWA, but the available data on its effectiveness and safety are quite good and comparable to those of RFA and MWA. All the three hyperthermia-based ablative techniques, when performed by skilled operators, can successfully treat all liver tumors eligible for thermal ablation, and to date in most centers of interventional oncology or interventional radiology the choice of the technique usually depends on the physician’s preference and experience, or technical availability. However, RFA, MWA, and LTA have peculiar advantages and limitations that can make each of them more suitable than the other ones to treat patients and tumors with different characteristics. When all the three thermal ablation techniques are available, the choice among RFA, MWA, and LTA should be guided by their advantages and disadvantages, number, size, and location of the liver nodules, and cost-saving considerations, in order to give patients the best treatment option.

Magnetic resonance imaging in the assessment of brain involvement in alcoholic and nonalcoholic Wernicke’s encephalopathy

AIM

To present the typical and atypical magnetic resonance (MR) imaging findings of alcoholic and non-alcoholic Wernicke’s encephalopathy.

METHODS

This study included 7 patients with Wernicke’s encephalopathy (2 men, 5 women; mean age, 52.3 years) that underwent brain MR examination between January 2012 and March 2016 in a single institution. Three patients were alcoholics and 4 patients were non-alcoholics. MR protocol included a T2-weighted sequence, a fluid attenuation inversion recovery (FLAIR) sequence, a diffusion-weighted sequence (b = 0 and 1000 s/mm²), and a contrast-enhanced MR sequence. All MR images were retrospectively reviewed at baseline and follow-up by two radiologists.

RESULTS

All patients with Wernicke’s encephalopathy had bilateral areas showing high signal intensity on both T2-weighted and FLAIR MR images in the typical sites (i.e., the periaqueductal region and the tectal plate). Signal intensity abnormalities in the atypical sites (i.e., the cerebellum and the cerebellar vermis) were seen in 4 patients, all of which had no history of alcohol abuse. Six patients had areas with restricted diffusion in the typical and atypical sites. Four patients had areas showing contrast-enhancement in the typical and atypical sites. Follow-up MR imaging within 6 mo after therapy (intravenous administration of thiamine) was performed in 4 patients, and demonstrated a complete resolution of all the signal intensities abnormalities previously seen in all patients.

CONCLUSION

MR imaging is valuable in the diagnosis of Wernicke’s encephalopathy particularly in patients presenting with atypical clinical symptoms, or with no history of alcohol abuse.

Evaluation of response to immune checkpoint inhibitors: Is there a role for positron emission tomography?

Strategies targeting intracellular negative regulators such as immune checkpoint inhibitors (ICPIs) have demonstrated significant antitumor activity across a wide range of solid tumors. In the clinical practice, the radiological effect of immunotherapeutic agents has raised several more relevant and complex challenges for the determination of their imaging-based response at single patient level. Accordingly, it has been suggested that the conventional Response Evaluation Criteria in Solid Tumors assessment alone, based on dimensional evaluation provided by computed tomography (CT), tends to underestimate the benefit of ICPIs at least in a subset of patients, supporting the need of immune-related response criteria. Different from CT, very few data are available for the evaluation of immunotherapy by means of ¹⁸F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET). Moreover, since the antineoplastic activity of ICPIs is highly related to the activation of T cells against cancer cells, FDG accumulation might cause false-positive findings. Yet, discrimination between benign and malignant processes represents a huge challenge for FDG-PET in this clinical setting. Consequently, it might be of high interest to test the complex and variegated response to ICPIs by means of PET and thus it is worthwhile to ask if a similar introduction of immune-related PET-based criteria could be proposed in the future. Finally, PET might offer a new insight into the biology and pathophysiology of ICPIs thanks to a growing number of non-invasive immune-diagnostic approaches based on non-FDG tracers.

Radiology education in Europe: Analysis of results from 22 European countries

AIM

To assess the state of radiology education across Europe by means of a survey study.

METHODS

A comprehensive 23-item radiology survey was distributed via email to the International Society of Radiology members, national radiological societies, radiologists and medical physicists. Reminders to complete the survey were sent and the results were analyzed over a period of 4 mo (January-April 2016). Survey questions include length of medical school and residency training; availability of fellowship and subspecialty training; number of residency programs in each country; accreditation pathways; research training; and medical physics education. Descriptive statistics were used to analyze and summarize data.

RESULTS

Radiology residency training ranges from 2-6 years with a median of 5 years, and follows 1 year of internship training in 55% (12 out of 22) European countries. Subspecialty fellowship training is offered in 55% (12 out of 22) European countries. Availability for specialization training by national societies is limited to eight countries. For nearly all respondents, less than fifty percent of radiologists travel abroad for specialization. Nine of 22 (41%) European countries have research requirements during residency. The types of certifying exam show variation where 64% (14 out of 22) European countries require both written and oral boards, 23% (5 out of 22) require oral examinations only, and 5% (1 out of 22) require written examinations only. A degree in medical physics is offered in 59% (13 out of 22) European countries and is predominantly taught by medical physicists. Nearly all respondents report that formal examinations in medical physics are required.

CONCLUSION

Comparative learning experiences across the continent will help guide the development of comprehensive yet pragmatic infrastructures for radiology education and collaborations in radiology education worldwide.

Radiation dose enhancement in skin therapy with nanoparticle addition: A Monte Carlo study on kilovoltage photon and megavoltage electron beams

AIM

To investigated the dose enhancement due to the incorporation of nanoparticles in skin therapy using the kilovoltage (kV) photon and megavoltage (MV) electron beams. Monte Carlo simulations were used to predict the dose enhancement when different types and concentrations of nanoparticles were added to skin target layers of varying thickness.

METHODS

Clinical kV photon beams (105 and 220 kVp) and MV electron beams (4 and 6 MeV), produced by a Gulmay D3225 orthovoltage unit and a Varian 21 EX linear accelerator, were simulated using the EGSnrc Monte Carlo code. Doses at skin target layers with thicknesses ranging from 0.5 to 5 mm for the photon beams and 0.5 to 10 mm for the electron beams were determined. The skin target layer was added with the Au, Pt, I, Ag and Fe₂O₃ nanoparticles with concentrations ranging from 3 to 40 mg/mL. The dose enhancement ratio (DER), defined as the dose at the target layer with nanoparticle addition divided by the dose at the layer without nanoparticle addition, was calculated for each nanoparticle type, nanoparticle concentration and target layer thickness.

RESULTS

It was found that among all nanoparticles, Au had the highest DER (5.2-6.3) when irradiated with kV photon beams. Dependence of the DER on the target layer thickness was not significant for the 220 kVp photon beam but it was for 105 kVp beam for Au nanoparticle concentrations higher than 18 mg/mL. For other nanoparticles, the DER was dependent on the atomic number of the nanoparticle and energy spectrum of the photon beams. All nanoparticles showed an increase of DER with nanoparticle concentration during the photon beam irradiations regardless of thickness. For electron beams, the Au nanoparticles were found to have the highest DER (1.01-1.08) when the beam energy was equal to 4 MeV, but this was drastically lower than the DER values found using photon beams. The DER was also found affected by the depth of maximum dose of the electron beam and target thickness. For other nanoparticles with lower atomic number, DERs in the range of 0.99-1.02 were found using the 4 and 6 MeV electron beams.

CONCLUSION

In nanoparticle-enhanced skin therapy, Au nanoparticle addition can achieve the highest dose enhancement with 105 kVp photon beams. Electron beams, while popular for skin therapy, did not produce as high dose enhancements as kV photon beams. Additionally, the DER is dependent on nanoparticle type, nanoparticle concentration, skin target thickness and energies of the photon and electron beams.

Potential role of imaging in assessing harmful effects on spermatogenesis in adult testes with varicocele

Varicocele is characterized by an abnormal dilatation and retrograde blood flow in the spermatic veins. Varicocele is the leading correctable cause of male infertility. Although it is highly prevalent in infertile men, it is also observed in individuals with normal fertility. Determining which men are negatively affected by varicocele would enable clinicians to better select those men who will benefit from treatment. To assess the functional status of the testes in men with varicocele, color Doppler sonographic parameters were evaluated. Testicular arterial blood flow was significantly reduced in men with varicocele, reflecting an impairment of spermatogenesis. An improvement in the testicular blood supply was found after varicocelectomy on spectral Doppler analysis. Testicular contrast harmonic imaging and elastography might improve our knowledge about the influence of varicocele on intratesticular microcirculation and tissue stiffness, respectively, providing possible information on the early damage of testicular structure by varicocele. Magnetic resonance imaging (MRI), with measurement of apparent diffusion coefficient has been used to assess the degree of testicular dysfunction and to evaluate the effectiveness of varicocele repair. Large prospective studies are needed to validate the possible role of functional sonography and MRI in the assessment of early defects of spermatogenesis in testes with varicocele.

Feasibility of imaging superficial palmar arch using micro-ultrasound, 7T and 3T magnetic resonance imaging

AIM

To demonstrate feasibility of vessel wall imaging of the superficial palmar arch using high frequency micro-ultrasound, 7T and 3T magnetic resonance imaging (MRI).

METHODS

Four subjects (ages 22-50 years) were scanned on a micro-ultrasound system with a 45-MHz transducer (Vevo 2100, VisualSonics). Subjects’ hands were then imaged on a 3T clinical MR scanner (Siemens Biograph MMR) using an 8-channel special purpose phased array carotid coil. Lastly, subjects’ hands were imaged on a 7T clinical MR scanner (Siemens Magnetom 7T Whole Body Scanner) using a custom built 8-channel transmit receive carotid coil. All three imaging modalities were subjectively analyzed for image quality and visualization of the vessel wall.

RESULTS

Results of this very preliminary study indicated that vessel wall imaging of the superficial palmar arch was feasible with a whole body 7T and 3T MRI in comparison with micro-ultrasound. Subjective analysis of image quality (1-5 scale, 1: poorest, 5: best) from B mode, ultrasound, 3T SPACE MRI and 7T SPACE MRI indicated that the image quality obtained at 7T was superior to both 3T MRI and micro-ultrasound. The 3D SPACE sequence at both 7T and 3T MRI with isotropic voxels allowed for multi-planar reformatting of images and allowed for less operator dependent results as compared to high frequency micro-ultrasound imaging. Although quantitative analysis revealed that there was no significant difference between the three methods, the 7T Tesla trended to have better visibility of the vessel and its wall.

CONCLUSION

Imaging of smaller arteries at the 7T is feasible for evaluating atherosclerosis burden and may be of clinical relevance in multiple diseases.

Gastric blunt traumatic injuries: A computed tomography grading classification

AIM

To produce a radiological grading of gastric traumatic injuries.

METHODS

In our study, we retrospectively analyzed 32 cases of blunt gastric traumatic injuries and compared computed tomography (CT) data with patients’ surgical or medical development. In all cases, a basal phase was acquired, and an intravenous contrast material was administered via an antecubital venous catheter with acquisition in the venous phase (70-90 s). In addition, a further set of delayed scans was performed 4-5 min after the first scanning session, without supplementary intravenous contrast material, to identify or better define areas of active bleeding. All CT examinations were retrospectively reviewed by two radiologists, with more than 5 years of experience in emergency radiology, to detect signs of gastric injuries and/or associated abdominal lesions according to literature data. Specific CT findings for gastric rupture include luminal content extravasation and discontinuity of the gastric wall, while CT findings suggestive of injury consisted of free peritoneal fluid, extraluminal air, pneumatosis, and thickening and hematoma of gastric wall.

RESULTS

We found 32 gastric traumatic injuries. In 22 patients (68.8%), the diagnosis was based on the surgical findings; in the other 10 patients (31.2%), the diagnosis was based on the clinical and CT radiological data. We observed discontinuity of the gastric wall and luminal content extravasation in 1 patient (3.1%); in 10 patients (31.2%), there was extra-luminal air in the peritoneum. In 28 patients (87.5%), there was peritoneal fluid, which was blood in 14 patients (hematoma in 11 patients and contrast material extravasation from active bleeding in 3 patients). In 15 patients (46.9%), there was gastric wall thickening. In 3 patients, it was possible to identify a prevalent involvement of the external layer of the gastric wall, whereas, in 2 patients, the inner side of the gastric wall presented with major involvement. In 3 patients (9.4%), pneumatosis of the gastric wall was detected. In 19 (59.4%) patients, the stomach was full. The fundus was the most frequently damaged part of the stomach because it was involved in 17 patients (53.1%). Based on the observed data, we identified four grades of gastric lesions.

CONCLUSION

A radiologic score is helpful for guiding the diagnosis and management (surgical or conservative) of gastric blunt traumatic injuries and stratify patients according to short-term outcomes.

Magnetic resonance enterography in Crohn’s disease: How we do it and common imaging findings

Crohn’s disease (CD) is a chronic inflammatory disease of the gastrointestinal tract, with unpredictable clinical course by phases of relapses alternating with other of quiescence. The etiology is multifactorial and is still not completely known; globally the westernization of lifestyle is causing an increasing incidence of CD, with peak age of 20-30 years. The diagnostic workup begins with the evaluation of the clinical history, physical examination and laboratory tests. However, the clinical assessment is subjected interobserver variability and, occasionally, the symptoms of acute and chronic inflammation may be indistinguishable. In this regards, the role of magnetic resonance (MR) enterography is crucial to determine the extension, the disease activity and the presence of any complications without ionizing radiations, making this method very suitable for young population affected by CD. The purpose of this review article is to illustrate the MR enterography technique and the most relevant imaging findings of CD, allowing the detection of small bowel involvement and the assessment of disease activity.

Multimodality functional imaging using DW-MRI and 18F-FDG-PET/CT during radiation therapy for human papillomavirus negative head and neck squamous cell carcinoma: Meixoeiro Hospital of Vigo Experience

AIM

To noninvasively investigate tumor cellularity measured using diffusion-weighted magnetic resonance imaging (DW-MRI) and glucose metabolism measured by ¹⁸F-labeled fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) during radiation therapy (RT) for human papillomavirus negative (HPV-) head and neck squamous cell carcinoma (HNSCC).

METHODS

In this prospective study, 6 HPV- HNSCC patients underwent a total of 34 multimodality imaging examinations (DW-MRI at 1.5 T Philips MRI scanner [(n = 24) pre-, during- (2-3 wk), and post-treatment (Tx), and ¹⁸F-FDG PET/CT pre- and post-Tx (n = 10)]. All patients received RT. Monoexponential modeling of the DW-MRI data yielded the imaging metric apparent diffusion coefficient (ADC) and the mean of standardized uptake value (SUV) was measured from ¹⁸F-FDG PET uptake. All patients had a clinical follow-up as the standard of care and survival status was documented at 1 year.

RESULTS

There was a strong negative correlation between the mean of pretreatment ADC (ρ = -0.67, P = 0.01) and the pretreatment ¹⁸F-FDG PET SUV. The percentage (%) change in delta (∆) ADC for primary tumors and neck nodal metastases between pre- and Wk_2-3 Tx were as follows: 75.4% and 61.6%, respectively, for the patient with no evidence of disease, 27.5% and 32.7%, respectively, for those patients who were alive with disease, and 26.9% and 7.31%, respectively, for those who were dead with disease.

CONCLUSION

These results are preliminary in nature and are indicative, and not definitive, trends rendered by the imaging metrics due to the small sample size of HPV- HNSCC patients in a Meixoeiro Hospital of Vigo Experience.

Cutting edge clinical applications in cardiovascular magnetic resonance

Today, the use of cardiovascular magnetic resonance (CMR) is widespread in clinical practice. The increased need to evaluate of subtle myocardial changes, coronary artery anatomy, and hemodynamic assessment has prompted the development of novel CMR techniques including T1 and T2 mapping, non-contrast angiography and four dimensional (4D) flow. T1 mapping is suitable for diagnosing pathologies affecting extracellular volume such as myocarditis, diffuse myocardial fibrosis and amyloidosis, and is a promising diagnostic tool for patients with iron overload and Fabry disease. T2 mapping is useful in depicting acute myocardial edema and estimating the amount of salvageable myocardium following an ischemic event. Novel angiography techniques, such as the self-navigated whole-heart or the quiescent-interval single-shot sequence, enable the visualization of the great vessels and coronary artery anatomy without the use of contrast material. The 4D flow technique overcomes the limitations of standard phase-contrast imaging and allows for the assessment of cardiovascular hemodynamics in the great arteries and flow patterns in the cardiac chambers. In conclusion, the future of CMR is heading toward a more reliable quantitative assessment of the myocardium, an improved non-contrast visualization of the coronary artery anatomy, and a more accurate evaluation of the cardiac hemodynamics.

Functional magnetic resonance imaging and the brain: A brief review

Functional magnetic resonance imaging (fMRI) is employed in many behavior analysis studies, with blood oxygen level dependent- (BOLD-) contrast imaging being the main method used to generate images. The use of BOLD-contrast imaging in fMRI has been refined over the years, for example, the inclusion of a spin echo pulse and increased magnetic strength were shown to produce better recorded images. Taking careful precautions to control variables during measurement, comparisons between different specimen groups can be illustrated by fMRI imaging using both quantitative and qualitative methods. Differences have been observed in comparisons of active and resting, developing and aging, and defective and damaged brains in various studies. However, cognitive studies using fMRI still face a number of challenges in interpretation that can only be overcome by imaging large numbers of samples. Furthermore, fMRI studies of brain cancer, lesions and other brain pathologies of both humans and animals are still to be explored.

Impact of contrast-enhanced ultrasound in patients with renal function impairment

AIM

To investigate the role of contrast enhanced ultrasound (CEUS) in evaluating patients with renal function impairment (RFI) showing: (1) acute renal failure (ARF) of suspicious vascular origin; or (2) suspicious renal lesions.

METHODS

We retrospectively evaluated patients addressed to CEUS over an eight years period to rule-out vascular causes of ARF (first group of 50 subjects) or assess previously found suspicious renal lesions (second group of 41 subjects with acute or chronic RFI). After preliminary grey-scale and color Doppler investigation, each kidney was investigated individually with CEUS, using 1.2-2.4 mL of a sulfur hexafluoride-filled microbubble contrast agent. Image analysis was performed in consensus by two readers who reviewed digital clips of CEUS. We calculated the detection rate of vascular abnormalities in the first group and performed descriptive statistics of imaging findings for the second group.

RESULTS

In the first group, CEUS detected renal infarction or cortical ischemia in 18/50 patients (36%; 95%CI: 23.3-50.9) and 1/50 patients (2%; 95%CI: 0.1-12), respectively. The detection rate of infarction was significantly higher (P = 0.0002; McNemar test) compared to color Doppler ultrasonography (10%). No vascular causes of ARF were identified in the remaining 31/50 patients (62%). In the second group, CEUS detected 41 lesions on 39 patients, allowing differentiation between solid lesions (21/41; 51.2%) vs complex cysts (20/41; 48.8%), and properly addressing 15/39 patients to intervention when feasible based on clinical conditions (surgery and cryoablation in 13 and 2 cases, respectively). Cysts were categorized Bosniak II, IIF, III and IV in 8, 5, 4 and 3 cases, respectively. In the remaining two patients, CEUS found 1 pseudolesion and 1 subcapsular hematoma.

CONCLUSION

CEUS showed high detection rate of renal perfusion abnormalities in patients with ARF, influencing the management of patients with acute or chronic RFI and renal masses throughout their proper characterization.

Computed tomography and patient risk: Facts, perceptions and uncertainties

Since its introduction in the 1970s, computed tomography (CT) has revolutionized diagnostic decision-making. One of the major concerns associated with the widespread use of CT is the associated increased radiation exposure incurred by patients. The link between ionizing radiation and the subsequent development of neoplasia has been largely based on extrapolating data from studies of survivors of the atomic bombs dropped in Japan in 1945 and on assessments of the increased relative risk of neoplasia in those occupationally exposed to radiation within the nuclear industry. However, the association between exposure to low-dose radiation from diagnostic imaging examinations and oncogenesis remains unclear. With improved technology, significant advances have already been achieved with regards to radiation dose reduction. There are several dose optimization strategies available that may be readily employed including omitting unnecessary images at the ends of acquired series, minimizing the number of phases acquired, and the use of automated exposure control as opposed to fixed tube current techniques. In addition, new image reconstruction techniques that reduce radiation dose have been developed in recent years with promising results. These techniques use iterative reconstruction algorithms to attain diagnostic quality images with reduced image noise at lower radiation doses.

Value of serial magnetic resonance imaging in the assessment of brain metastases volume control during stereotactic radiosurgery

AIM

To evaluate brain metastases volume control capabilities of stereotactic radiosurgery (SRS) through serial magnetic resonance (MR) imaging follow-up.

METHODS

MR examinations of 54 brain metastases in 31 patients before and after SRS were reviewed. Patients were included in this study if they had a pre-treatment MR examination and serial follow-up MR examinations at 6 wk, 9 wk, 12 wk, and 12 mo after SRS. The metastasis volume change was categorized at each follow-up as increased (> 20% of the initial volume), stable (± 20% of the initial volume) or decreased (< 20% of the initial volume).

RESULTS

A local tumor control with a significant (P < 0.05) volume decrease was observed in 25 metastases at 6-wk follow-up. Not significant volume change was observed in 23 metastases and a significant volume increase was observed in 6 metastases. At 9-wk follow-up, 15 out of 25 metastases that decreased in size at 6 wk had a transient tumor volume increase, followed by tumor regression at 12 wk. At 12-wk follow-up there was a significant reduction in volume in 45 metastases, and a significant volume increase in 4 metastases. At 12-mo follow-up, 19 metastases increased significantly in size (up to 41% of the initial volume). Volume tumor reduction was correlated to histopathologic subtype.

CONCLUSION

SRS provided an effective local brain metastases volume control that was demonstrated at follow-up MR imaging.

Assessment of fetus during second trimester ultrasonography using HDlive software: What is its real application in the obstetrics clinical practice?

AIM

To show imaging results from application of four-dimensional (4D) ultrasound lightening technique (HDlive™) in clinical obstetrics practice.

METHODS

Normal and abnormal fetuses at second and third trimester of pregnancy undergoing routine scan with 4D HDlive™ (5DUS) in the rendering mode are described. Realistic features of fetal structures were provided by 5DUS in the rendering mode. Normal anatomy as well as pathology like cleft lip, hypoplastic face, micrognathia, low-set ears, corpus callosum, arthrogryposis, aortic arch, left congenital diaphragmatic hernia are highlighted in this study. Anatomical details of the fetuses were provided by 5DUS with higher quality imaging modality compared to those obtained using conventional 2D/3D ultrasound.

RESULTS

Realistic views of fetal anatomy details were displayed by means of 5DUS in the rendering mode, with high image quality obtained either in low-risk or in high-risk obstetrics population. Corpus callosum, esophagus, and aortic arch were obtained in normal fetuses. Cleft lip, cleft lip and palate, micrognathia, hypoplastic face, low-set ears, arthrogryposis, left congenital diaphragmatic hernia, exomphalos, and clitoris hypertrophy were clearly rendered by 5DUS application.

CONCLUSION

The use of 5DUS in the rendering mode, when clinical available, was diagnostic in a variety of congenital anomalies, aided understanding of the parents-to-be and improved prenatal counseling and perinatal management.

Commentary on: “Evaluation of variations in sinonasal region with computed tomography”

This letter is a commentary on the article titled “Evaluation of variations in sinonasal region with computed tomography”, published in the January 2016 issue of World Journal of Radiology. The authors definition of the secondary middle turbinate is incorrect. The authors stated that the secondary middle turbinate is an accessory turbinate that is seen between the superior and middle turbinates. It should originate from the middle meatus posterosuperior to the ethmoid infundibulum.

Horizontally root fractured teeth with pulpal vitality - two case reports

This case study reports the successful outcome of horizontal root fractures of two different patients, which took place in permanent incisors. Report 1 describes a case of a 29-year-old patient who suffered a mandibular trauma affecting mainly the lower central incisors, caused by a car accident. A panoramic radiograph was taken right after the accident and showed a horizontal root fracture in the middle third of tooth 42, which went untreated. Report 2 illustrates a case of a 17-year-old male patient who searched for orthodontic therapy and the periapical radiograph showed horizontal root fracture in tooth 11 caused by a previous trauma, which went untreated as well. There was healing through the reestablishment of pulp activity and dental coloration without professional intervention.

Mechanisms underlying 18F-fluorodeoxyglucose accumulation in colorectal cancer

Positron emission tomography (PET) with ¹⁸F-fluorodeoxyglucose (FDG) is a diagnostic tool to evaluate metabolic activity by measuring accumulation of FDG, an analogue of glucose, and has been widely used for detecting small tumors, monitoring treatment response and predicting patients’ prognosis in a variety of cancers. However, the molecular mechanism of FDG accumulation into tumors remains to be investigated. It is well-known that most cancers are metabolically active with elevated glucose metabolism, a phenomenon known as the Warburg effect. The underlying mechanisms for elevated glucose metabolism in cancer tissues are complex. Recent reports have indicated the potential of FDG-PET/CT scans in predicting mutational status (e.g., KRAS gene mutation) of colorectal cancer (CRC), which suggests that FDG-PET/CT scans may play a key role in determining therapeutic strategies by non-invasively predicting treatment response to anti-epidermal growth factor receptor (EGFR) therapy. In this review, we summarize the current findings investigating the molecular mechanism of ¹⁸F-FDG accumulation in CRC.

Diffusion-weighted imaging of the liver: Current applications

Diffusion-weighted imaging (DWI) of the liver can be performed using most commercially available machines and is currently accepted in routine sequence. This sequence has some potential as an imaging biomarker for fibrosis, tumor detection/characterization, and following/predicting therapy. To improve reliability including accuracy and reproducibility, researchers have validated this new technique in terms of image acquisition, data sampling, and analysis. The added value of DWI in contrast-enhanced magnetic resonance imaging was established in the detection of malignant liver lesions. However, some limitations remain in terms of lesion characterization and fibrosis detection. Furthermore, the methodologies of image acquisition and data analysis have been inconsistent. Therefore, researchers should make every effort to not only improve accuracy and reproducibility but also standardize imaging parameters.

Radiological imaging findings of scheuermann disease

AIM

To find accompanying anomalies of typical and atypical Scheuermann’s disease (SD) is reported in the present study.

METHODS

Study included 20 patients (16 men and 4 women) who had radiological imaging radiography, magnetic resonance imaging (MRI) and computed tomography, if available, due to back pain, curved back and low back pain in November 2011-February 2016 period. Patients were categorized into typical and atypical patterns based on the region involved. Thoracic kyphosis values were measured using real Cobb angle. Accompanying disc degeneration, herniations and spinal cord pathologies were studied using MRI.

RESULTS

Age of the patients ranged from 11.0 to 23.0 (mean 17.2 ± 3.0). Typical pattern of SD were detected in 15 patients while atypical pattern were detected in 5 patients. Cobb angle range was 40.2-67.2 (mean 55.5 ± 8.7) in typical Scheuermann’s patients and 24.7-49.9 (mean 36.7 ± 10.8) in atypical ones. Intervertebral level was affected and had the measures of 3-8 (mean 5.3 ± 1.6) and 7-9 (mean 8.2 ± 0.8) in typical and atypical Scheuermann’s patients, respectively. Level of degenerative disc disease in MRI was 1-7 discs (mean 4.1 ± 1.7) in typical patients and 5-10 discs (mean 7.6 ± 1.9) in atypical patients.

CONCLUSION

SD can be seen in typical and atypical patterns, typical being more frequent. Because degenerative disc diseases, herniations and cord pathologies such as syringomyelia can accompany SD (albeit more common in atypical pattern), it is necessary to evaluate these patients with plain radiography and MRI together.

Metabolic positron emission tomography imaging of cancer: Pairing lipid metabolism with glycolysis

The limitations of fluorine-18 fluorodeoxy-D-glucose (FDG) in detecting some cancers has prompted a longstanding search for other positron emission tomography (PET) tracers to complement the imaging of glycolysis in oncology, with much attention paid to lipogenesis based on observations that the production of various lipid and lipid-containing compounds is increased in most cancers. Radiolabeled analogs of choline and acetate have now been used as oncologic PET probes for over a decade, showing convincingly improved detection sensitivity over FDG for certain cancers. However, neither choline nor acetate have been thoroughly validated as lipogenic biomarkers, and while acetyl-CoA produced from acetate is used in de-novo lipogenesis to synthesize fatty acids, acetate is also consumed by various other synthetic and metabolic pathways, with recent experimental observations challenging the assumption that lipogenesis is its predominant role in all cancers. Since tumors detected by acetate PET are also frequently detected by choline PET, imaging of choline metabolism might serve as an alternative albeit indirect marker of lipogenesis, particularly if the fatty acids produced in cancer cells are mainly destined for membrane synthesis through incorporation into phosphatidylcholines. Aerobic glycolysis may or may not coincide with changes in lipid metabolism, resulting in combinatorial metabolic phenotypes that may have different prognostic or therapeutic implications. Consequently, PET imaging using dual metabolic tracers, in addition to being diagnostically superior to imaging with individual tracers, could eventually play a greater role in supporting precision medicine, as efforts to develop small-molecule metabolic pathway inhibitors are coming to fruition. To prepare for this advent, clinical and translational studies of metabolic PET tracers must go beyond simply estimating tracer diagnostic utility, and aim to uncover potential therapeutic avenues associated with these metabolic alterations.

Sonoelastography in the musculoskeletal system: Current role and future directions

Ultrasound is an essential modality within musculoskeletal imaging, with the recent addition of elastography. The elastic properties of tissues are different from the acoustic impedance used to create B mode imaging and the flow properties used within Doppler imaging, hence elastography provides a different form of tissue assessment. The current role of ultrasound elastography in the musculoskeletal system will be reviewed, in particular with reference to muscles, tendons, ligaments, joints and soft tissue tumours. The different ultrasound elastography methods currently available will be described, in particular strain elastography and shear wave elastography. Future directions of ultrasound elastography in the musculoskeletal system will also be discussed.

CO2BOLD assessment of moyamoya syndrome: Validation with single photon emission computed tomography and positron emission tomography imaging

AIM

To compare the assessment of cerebrovascular reserve (CVR) using CO₂BOLD magnetic resonance imaging (MRI) vs positron emission tomography (PET) and single photon emission computed tomography (SPECT) as reference standard.

METHODS

Ten consecutive patients (8 women, mean age of 41 ± 26 years) with moyamoya syndrome underwent 14 pre-surgical evaluations for external-internal carotid artery bypass surgery. CVR was assessed using CO₂BOLD and PET (4)/SPECT (11) with a maximum interval of 36 d, and evaluated by two experienced neuroradiologists.

RESULTS

The inter-rater agreement was 0.81 for SPECT (excellent), 0.43 for PET (fair) and 0.7 for CO₂BOLD (good). In 9/14 cases, there was a correspondence between CO₂BOLD and PET/SPECT. In 4/14 cases, CVR was over-estimated in CO₂BOLD, while in 1/14 case, CVR was underestimated in CO₂BOLD. The sensitivity of CO₂BOLD was 86% and a specificity of 43%.

CONCLUSION

CO₂BOLD can be used for pre-surgical assessment of CVR in patients with moyamoya syndrome and combines the advantages of absent irradiation, high availability of MRI and assessment of brain parenchyma, cerebral vessels and surrogate CVR in one stop.

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.

Radium-223 and metastatic castration-resistant prostate cancer: All that glitters is not gold

After being approved by the National Drug Agency in several countries, Radium-223 (Ra-223) is gaining wide acceptance in the treatment of bone metastatic castration resistant prostate cancer. The exact mechanism of action remain unclear: The established model of direct alpha-particle irradiation from the remodelling bone surface, where Ra-223 accumulates, surrounding the tumor foci can explain a lethal effect only on metastatic microdeposits, but not on higher tumor burden. According to the “pre-metastatic niche model”, it is likely that Ra-223 targets several non-tumoral cell types of the tumor microenvironment involved in the complex mechanism of cancer bone homing and colonization. A deeper insight into this hypothetical mechanism will lead to a more accurate dosimetric approach and to find optimal sequencing and/or combination with the other therapeutic options.

Presumptive case of sparganosis manifesting as a hepatic mass: A case report and literature review

A 60-year-old man was admitted due to rectosigmoid colon cancer, and a hepatic mass was incidentally found during the staging work-up. The mass appeared cystic with a thick wall and contained multiple bizarre cord-like structures on ultrasound, computed tomography and magnetic resonance imaging. The differential diagnoses included organizing abscess/hematoma, foreign body granuloma and parasite infestation. Serologic study revealed anti-sparganum antibodies. Over 4-year follow-up, the patient did not complain of symptoms, and no changes in the characteristics of the liver mass were observed. Hepatic sparganosis is rare; only two cases have been clinically reported, and no detailed radiologic description was available until now. This case report presents a detailed radiologic description of a hepatic mass that could most likely represent hepatic sparganosis.

Role of molecular imaging in the management of patients affected by inflammatory bowel disease: State-of-the-art

AIM

To present the current state-of-the art of molecular imaging in the management of patients affected by inflammatory bowel disease (IBD).

METHODS

A systematic review of the literature was performed in order to find important original articles on the role of molecular imaging in the management of patients affected by IBD. The search was updated until February 2016 and limited to articles in English.

RESULTS

Fifty-five original articles were included in this review, highlighting the role of single photon emission tomography and positron emission tomography.

CONCLUSION

To date, molecular imaging represents a useful tool to detect active disease in IBD. However, the available data need to be validated in prospective multicenter studies on larger patient samples.

Imaging pancreatic islet cells by positron emission tomography

It was estimated that every year more than 30000 persons in the United States - approximately 80 people per day - are diagnosed with type 1 diabetes (T1D). T1D is caused by autoimmune destruction of the pancreatic islet (β cells) cells. Islet transplantation has become a promising therapy option for T1D patients, while the lack of suitable tools is difficult to directly evaluate of the viability of the grafted islet over time. Positron emission tomography (PET) as an important non-invasive methodology providing high sensitivity and good resolution, is able to accurate detection of the disturbed biochemical processes and physiological abnormality in living organism. The successful PET imaging of islets would be able to localize the specific site where transplanted islets engraft in the liver, and to quantify the level of islets remain alive and functional over time. This information would be vital to establishing and evaluating the efficiency of pancreatic islet transplantation. Many novel imaging agents have been developed to improve the sensitivity and specificity of PET islet imaging. In this article, we summarize the latest developments in carbon-11, fluorine-18, copper-64, and gallium-68 labeled radioligands for the PET imaging of pancreatic islet cells.

Effects of oral contrast on dose in abdominopelvic computed tomography with pure iterative reconstruction

AIM

To assess the effect of neutral (NC) and positive (PC) oral contrast use on patient dose in low-dose abdominal computed tomography (CT).

METHODS

Low-dose clinically indicated CTs were performed on 79 Crohn’s patients (35 = PC, 1 L 2% gastrografin; 44 = NC, 1.5 L polyethylene glycol). Scanner settings for both acquisitions were identical apart from 25 s difference in intravenous contrast timing. Body mass index (BMI), scan-ranges, dose-length product and size-specific dose estimated were recorded. Data was reconstructed with pure model-based iterative reconstruction. Image quality was objectively and subjectively analysed. Data analysis was performed with Statistical Package for Social Scientists.

RESULTS

Higher doses were seen in neutral contrast CTs (107.60 ± 78.7 mGy.cm, 2.47 ± 1.21 mGy vs 85.65 ± 58.2 mGy.cm, 2.18 ± 0.96 mGy). The difference was significant in 2 of 4 BMI groups and in those that had both NC and PC investigations. Image-quality assessment yielded 6952 datapoints. NC image quality was significantly superior (P < 0.001) (objective noise, objective signal to noise ratio, subjective spatial resolution, subjective contrast resolution, diagnostic acceptability) at all levels. NC bowel distension was significantly (P < 0.001) superior.

CONCLUSION

The use of polyethylene glycol as a neutral OC agent leads to higher radiation doses than standard positive contrast studies, in low dose abdominal CT imaging. This is possibly related to the osmotic effect of the agent resulting in larger intraluminal fluid volumes and resultant increased overall beam attenuation.

Thoracic ultrasound: An adjunctive and valuable imaging tool in emergency, resource-limited settings and for a sustainable monitoring of patients

Imaging workup of patients referred for elective assessment of chest disease requires an articulated approach: Imaging is asked for achieving timely diagnosis. The concurrent or subsequent use of thoracic ultrasound (TUS) with conventional (chest X-rays-) and more advanced imaging procedures (computed tomography and magnetic resonance imaging) implies advantages, limitations and actual problems. Indeed, despite TUS may provide useful imaging of pleura, lung and heart disease, emergency scenarios are currently the most warranted field of application of TUS: Pleural effusion, pneumothorax, lung consolidation. This stems from its role in limited resources subsets; actually, ultrasound is an excellent risk reducing tool, which acts by: (1) increasing diagnostic certainty; (2) shortening time to definitive therapy; and (3) decreasing problems from blind procedures that carry an inherent level of complications. In addition, paediatric and newborn disease are particularly suitable for TUS investigation, aimed at the detection of congenital or acquired chest disease avoiding, limiting or postponing radiological exposure. TUS improves the effectiveness of elective medical practice, in resource-limited settings, in small point of care facilities and particularly in poorer countries. Quality and information provided by the procedure are increased avoiding whenever possible artefacts that can prevent or mislead the achievement of the correct diagnosis. Reliable monitoring of patients is possible, taking into consideration that appropriate expertise, knowledge, skills, training, and even adequate equipment’s suitability are not always and everywhere affordable or accessible. TUS is complementary imaging procedure for the radiologist and an excellent basic diagnostic tool suitable to be shared with pneumologists, cardiologists and emergency physicians.

Evaluation of DNA synthesis with carbon-11-labeled 4′-thiothymidine

In the cancer research field, the preferred method for evaluating the proliferative activity of cancer cells in vivo is to measure DNA synthesis rates. The cellular proliferation rate is one of the most important cancer characteristics, and represents the gold standard of pathological diagnosis. Positron emission tomography (PET) has been used to evaluate in vivo DNA synthetic activity through visualization of enhanced nucleoside metabolism. However, methods for the quantitative measurement of DNA synthesis rates have not been fully clarified. Several groups have been engaged in research on 4′-[methyl-¹¹C]-thiothymidine (¹¹C-4DST) in an effort to develop a PET tracer that allows quantitative measurement of in vivo DNA synthesis rates. This mini-review summarizes the results of recent studies of the in vivo measurement of cancer DNA synthesis rates using ¹¹C-4DST.

Diffusion weighted imaging: Technique and applications

Diffusion weighted imaging (DWI) is a method of signal contrast generation based on the differences in Brownian motion. DWI is a method to evaluate the molecular function and micro-architecture of the human body. DWI signal contrast can be quantified by apparent diffusion coefficient maps and it acts as a tool for treatment response evaluation and assessment of disease progression. Ability to detect and quantify the anisotropy of diffusion leads to a new paradigm called diffusion tensor imaging (DTI). DTI is a tool for assessment of the organs with highly organised fibre structure. DWI forms an integral part of modern state-of-art magnetic resonance imaging and is indispensable in neuroimaging and oncology. DWI is a field that has been undergoing rapid technical evolution and its applications are increasing every day. This review article provides insights in to the evolution of DWI as a new imaging paradigm and provides a summary of current role of DWI in various disease processes.

Peripheral nerve imaging: Not only cross-sectional area

Peripheral nerve imaging is recognized as a complement to clinical and neurophysiological assessment in the evaluation of peripheral nerves with the ability to impact patient management, even for small and difficult nerves. The European Society of Musculoskeletal Radiology, suggest to use ultrasound (US) for nerve evaluation due to the fact that, in sever anatomical area, magnetic resonance imaging is not able to give additional informations. US could be considered the first-choice approach for the assessment of peripheral nerves. The relative drawback of peripheral nerve US is the long learning curve and the deep anatomic competence to evaluate even small nerves. In the recent years, the role of US in peripheral nerve evaluation has been widened. In the past, nerve US was mainly used to assess nerve-cross sectional area, but now more advanced measurements and considerations are desirable and can boost the role of peripheral nerve US. Nerve echotexture evaluation was defined in 2010: The ratio between the hypoechoic and hyperechoic areas of peripheral nerves on US was called “nerve density”. For evaluation of patients who have peripheral neuropathies, the role of peripheral nerve is US wider than simple cross-sectional area evaluation. Quantitative measurements describing the internal fascicular echotexture of peripheral nerves introduce the concept of considering US as a possible quantitative imaging biomarker technique. The potential of nerve US has started to be uncovered. It seems clear that only cross-sectional area measurement is no more sufficient for a comprehensive US evaluation of peripheral nerves.

Enhanced characterization of solid solitary pulmonary nodules with Bayesian analysis-based computer-aided diagnosis

The aim of this study was to prospectively assess the accuracy gain of Bayesian analysis-based computer-aided diagnosis (CAD) vs human judgment alone in characterizing solitary pulmonary nodules (SPNs) at computed tomography (CT). The study included 100 randomly selected SPNs with a definitive diagnosis. Nodule features at first and follow-up CT scans as well as clinical data were evaluated individually on a 1 to 5 points risk chart by 7 radiologists, firstly blinded then aware of Bayesian Inference Malignancy Calculator (BIMC) model predictions. Raters’ predictions were evaluated by means of receiver operating characteristic (ROC) curve analysis and decision analysis. Overall ROC area under the curve was 0.758 before and 0.803 after the disclosure of CAD predictions (P = 0.003). A net gain in diagnostic accuracy was found in 6 out of 7 readers. Mean risk class of benign nodules dropped from 2.48 to 2.29, while mean risk class of malignancies rose from 3.66 to 3.92. Awareness of CAD predictions also determined a significant drop on mean indeterminate SPNs (15 vs 23.86 SPNs) and raised the mean number of correct and confident diagnoses (mean 39.57 vs 25.71 SPNs). This study provides evidence supporting the integration of the Bayesian analysis-based BIMC model in SPN characterization.

Helical tomotherapy and volumetric modulated arc therapy: New therapeutic arms in the breast cancer radiotherapy

AIM

To analyse clinical and dosimetric results of helical tomotherapy (HT) and volumetric modulated arc therapy (VMAT) in complex adjuvant breast and nodes irradiation.

METHODS

Seventy-three patients were included (31 HT and 42 VMAT). Dose were 63.8 Gy (HT) and 63.2 Gy (VMAT) in the tumour bed, 52.2 Gy in the breast, 50.4 Gy in supraclavicular nodes (SCN) and internal mammary chain (IMC) with HT and 52.2 Gy and 49.3 Gy in IMC and SCN with VMAT in 29 fractions. Margins to particle tracking velocimetry were greater in the VMAT cohort (7 mm vs 5 mm).

RESULTS

For the HT cohort, the coverage of clinical target volumes was as follows: Tumour bed: 99.4% ± 2.4%; breast: 98.4% ± 4.3%; SCN: 99.5% ± 1.2%; IMC: 96.5% ± 13.9%. For the VMAT cohort, the coverage was as follows: Tumour bed: 99.7% ± 0.5%, breast: 99.3% ± 0.7%; SCN: 99.6% ± 1.4%; IMC: 99.3% ± 3%. For ipsilateral lung, Dmean and V20 were 13.6 ± 1.2 Gy, 21.1% ± 5% (HT) and 13.6 ± 1.4 Gy, 20.1% ± 3.2% (VMAT). Dmean and V30 of the heart were 7.4 ± 1.4 Gy, 1% ± 1% (HT) and 10.3 ± 4.2 Gy, 2.5% ± 3.9% (VMAT). For controlateral breast Dmean was 3.6 ± 0.2 Gy (HT) and 4.6 ± 0.9 Gy (VMAT). Acute skin toxicity grade 3 was 5% in the two cohorts.

CONCLUSION

HT and VMAT in complex adjuvant breast irradiation allow a good coverage of target volumes with an acceptable acute tolerance. A longer follow-up is needed to assess the impact of low doses to healthy tissues.

Relative volume measured with magnetic resonance imaging is an articular collapse predictor in hematological pediatric patients with femoral head osteonecrosis

AIM

To assess the potential value of femoral head (FH) volume measurements to predict joint collapse, as compared to articular surface involvement, in post-treatment osteonecrosis (ON) in pediatric patients affected by lymphoproliferative diseases.

METHODS

Considering 114 young patients with lymphoproliferative diseases undergone a lower-limbs magnetic resonance imaging (MRI) examination between November 2006 and August 2012 for a suspected post-treatment ON, we finally considered a total of 13 cases (7 males, mean age 15.2 ± 4.8 years), which developed a FH ON lesions (n = 23). The MRI protocol included coronal short tau inversion recovery and T1-weighted sequences, from the hips to the ankles. During the follow-up (elapsed time: 9.2 ± 2 mo), 13/23 FH articular surface (FHS) developed articular deformity. The first MRI studies with diagnosis of ON were retrospectively analyzed, measuring FH volume (FHV), FHS, ON volume (ONV) and the articular surface involved by ON (ONS). The relative involvement of FHS, in terms of volume [relative volume (RV): ONV/FHV] and articular surface [relative surface (RS): ONS/FHS], was then calculated.

RESULTS

By using receiver operating characteristic curve analysis (threshold of 23% of volume involvement), RV predicted articular deformity in 13/13 FHS [sensitivity 100%, specificity 90%, accuracy 95%, positive predictive value (PPV) 93%, negative predictive value (NPV) 100%]. Considering a threshold of 50% of articular involvement, RS predicted articular deformity in 10/13 femoral heads (sensitivity 77%, specificity 100%, accuracy 87%, PPV 100%, NPV 77%).

CONCLUSION

RV might be a more reliable parameter than RS in predicting FH deformity and could represent a potential complementary diagnostic tool in the follow-up of femoral heads ON lesions.

Tumor characteristics of ductal carcinoma in situ of breast visualized on [F-18] fluorodeoxyglucose-positron emission tomography/computed tomography: Results from a retrospective study

AIM

To clarify clinicopathological features of ductal carcinoma in situ (DCIS) visualized on [F-18] fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT).

METHODS

This study retrospectively reviewed 52 consecutive tumors in 50 patients with pathologically proven pure DCIS who underwent [F-18] FDG-PET/CT before surgery. [F-18] FDG-PET/CT was performed after biopsy in all patients. The mean interval from biopsy to [F-18] FDG-PET/CT was 29.2 d. [F-18] FDG uptake by visual analysis and maximum standardized uptake value (SUVmax) was compared with clinicopathological characteristics.

RESULTS

[F-18] FDG uptake was visualized in 28 lesions (53.8%) and the mean and standard deviation of SUVmax was 1.63 and 0.90. On univariate analysis, visual analysis and the SUVmax were associated with symptomatic presentation (P = 0.012 and 0.002, respectively), palpability (P = 0.030 and 0.024, respectively), use of core-needle biopsy (CNB) (P = 0.023 and 0.012, respectively), ultrasound-guided biopsy (P = 0.040 and 0.006, respectively), enhancing lesion ≥ 20 mm on magnetic resonance imaging (MRI) (P = 0.001 and 0.010, respectively), tumor size ≥ 20 mm on histopathology (P = 0.002 and 0.008, respectively). However, [F-18] FDG uptake parameters were not significantly associated with age, presence of calcification on mammography, mass formation on MRI, presence of comedo necrosis, hormone status (estrogen receptor, progesterone receptor and human epidermal growth factor receptor-2), and nuclear grade. The factors significantly associated with visual analysis and SUVmax were symptomatic presentation (P = 0.019 and 0.001, respectively), use of CNB (P = 0.001 and 0.031, respectively), and enhancing lesion ≥ 20 mm on MRI (P = 0.001 and 0.049, respectively) on multivariate analysis.

CONCLUSION

Although DCIS of breast is generally non-avid tumor, symptomatic and large tumors (≥ 20 mm) tend to be visualized on [F-18] FDG-PET/CT.

Unusual presentation of Erdheim-Chester disease in a child with acute lymphoblastic leukemia

Erdheim-Chester disease (ECD) is an uncommon, non-familial, non-Langerhans cell histiocytosis, which involves skeletal system and soft tissue usually in middle aged and elderly patients. The characteristic radiologic features include bilateral, symmetric cortical osteosclerosis of the diaphyseal and metaphyseal parts of the long bones, or bilateral symmetrically abnormal intense ^99mTechnetium labelling of the metaphyseal-diaphyseal region of the long bones, and computed tomography scan findings of “coated aorta” or “hairy kidneys”. ECD in childhood with osteolytic lesion is extremely rare. We describe an unusual case with an expansile lytic bone lesion at presentation in a case of acute lymphoblastic leukemia.