Coxa pedis: can calcaneal pronation angle be considered a predictive sign of medial plantar arch overload?

PURPOSE

To assess whether a correlation between the calcaneal pronation angle and the presence of internal plantar arch overload signs (such as upper-medial spring ligament lesion, posterior tibial tendon tenosynovitis, etc.) could lead to a better understanding of coxa pedis pathology.

MATERIAL AND METHODS

One hundred ankle MRIs of consecutive patients were retrospectively reviewed measuring the calcaneal pronation angle and either the presence or absence of internal plantar arch overload signs. Next, the association of overload signs with increasing pronation angle was evaluated to establish a cut-off point beyond which coxa pedis pathology could be defined.

RESULTS

The tibial-calcaneal angle values in patients with and without effusion proved to be significantly different (p < 0.0001). The tibial-calcaneal angle values in patients with and without oedema also demonstrated a significant difference (p < 0.0056). Regarding posterior tibial tendon, a significant difference was found between the two groups (p < 0.0001). For plantar fascia enthesopathy, the result was borderline significant (p < 0.054). A linear correlation was found between the value of pronation angle and the extent of spring ligament injury (p < 0.0001). In contrast, no correlation with age was found.

CONCLUSION

In conclusion, the literature associates medial longitudinal plantar arch overload with posterior tibial tendinopathy and spring ligament complex injuries. Our data show that both injuries are highly correlated with increased calcaneal pronation angle, which could be considered a predictive sign of internal plantar arch overload, prior to the development of the associated signs.

Characterisation of a Silicon Photomultiplier Based Oncological Brachytherapy Fibre Dosimeter

Source localisation and real-time dose verification are at the forefront of medical research in brachytherapy, an oncological radiotherapy procedure based on radioactive sources implanted in the patient body. The ORIGIN project aims to respond to this medical community's need by targeting the development of a multi-point dose mapping system based on fibre sensors integrating a small volume of scintillating material into the tip and interfaced with silicon photomultipliers operated in counting mode. In this paper, a novel method for the selection of the optimal silicon photomultipliers to be used is presented, as well as a laboratory characterisation based on dosimetric figures of merit. More specifically, a technique exploiting the optical cross-talk to maintain the detector linearity in high-rate conditions is demonstrated. Lastly, it is shown that the ORIGIN system complies with the TG43-U1 protocol in high and low dose rate pre-clinical trials with actual brachytherapy sources, an essential requirement for assessing the proposed system as a dosimeter and comparing the performance of the system prototype against the ORIGIN project specifications.

Role of MRI and added value of diffusion-weighted and gadolinium-enhanced MRI for the diagnosis of local recurrence from rectal cancer

PURPOSE

To evaluate whether the addition of gadolinium-enhanced MRI and diffusion-weighted imaging (DWI) improves T2 sequence performance for the diagnosis of local recurrence (LR) from rectal cancer and to assess which approach is better at formulating this diagnosis among readers with different experience.

METHODS

Forty-three patients with suspected LR underwent pelvic MRI with T2 weighted (T2) sequences, gadolinium fat-suppressed T1 weighted sequences (post-contrast T1), and DWI sequences. Three readers (expert: G, intermediate: E, resident: V) scored the likelihood of LR on T2, T2 + post-contrast T1, T2 + DWI, and T2 + post-contrast T1 + DWI.

RESULTS

In total, 18/43 patients had LR; on T2 images, the expert reader achieved an area under the ROC curve (AUC) of 0.916, sensitivity of 88.9%, and specificity of 76%; the intermediate reader achieved values of 0.890, 88.9%, and 48%, respectively, and the resident achieved values of 0.852, 88.9%, and 48%, respectively. DWI significantly improved the AUC value for the expert radiologist by up to 0.999 (p = 0.04), while post-contrast T1 significantly improved the AUC for the resident by up to 0.950 (p = 0.04). For the intermediate reader, both the T2 + DWI AUC and T2 + post-contrast T1 AUC were better than the T2 AUC (0.976 and 0.980, respectively), but with no statistically significant difference. No statistically significant difference was achieved by any of the three readers by comparing either the T2 + DWI AUCs to the T2 + post-contrast T1 AUCs or the AUCs of the two pairs of sequences to those of the combined three sequences. Furthermore, using the T2 sequences alone, all of the readers achieved a fair number of "equivocal" cases: they decreased with the addition of either DWI or post-contrast T1 sequences and, for the two less experienced readers, they decreased even more with the three combined sequences.

CONCLUSIONS

Both DWI and T1 post-contrast MRI increased diagnostic performance for LR diagnosis compared to T2; however, no significant difference was observed by comparing the two different pairs of sequences with the three combined sequences.

Ability of specific and nonspecific signs of multidetector computed tomography (MDCT) in the diagnosis of blunt surgically important bowel and mesenteric injuries

PURPOSE

To determine the accuracy of MDCT in the evaluation of blunt surgically relevant bowel and/or mesenteric injuries (BMIs) using single specific CT signs together with specific pairs of nonspecific signs.

METHODS

Fifty-four patients examined with MDCT were divided into two groups: a 'surgical' group of 20 patients-which underwent surgery for blunt BMIs-and a control group of 34 'nonsurgical' trauma patients. Two radiologists with different experience performed a double-blind retrospective evaluation of the images, classifying the patients in the two groups by using only single specific signs; then, the images were reviewed in consensus with a third radiologist and sensitivity and specificity were calculated. Subsequently, the frequency of every single sign and of every possible combination of nonspecific signs in the two groups was registered, to find combinations present only in the surgical group; sensitivity and specificity were calculated by using even those specific combinations.

RESULTS

At the first consensual evaluation, sensitivity and specificity were 75 and 100%, respectively. Two combinations of nonspecific signs (focal wall thickening + extraluminal air; focal wall thickening + seat belt sign) were found only in surgical patients that did not present any single specific sign: Sensitivity calculated adding those two combinations was 95%, without a decrease in specificity.

CONCLUSIONS

MDCT is an accurate technique in the evaluation of blunt surgically relevant BMIs. The single specific CT signs were sufficient for the diagnosis in only 75% of the cases; adding the two specific combinations allowed an increase in sensitivity of 20%.

Immunoassay of Neuron-Specific Enolase (Nse) and Serum Fragments of Cytokeratin 19 (Cyfra 21.1) as Tumor Markers in Small Cell Lung Cancer: Clinical Evaluation and Biological Hypothesis

NSE is a biochemical marker for small cell lung cancer (SCLC) diagnosis and management. CYFRA 21.1 is a newly developed immunoassay to detect the serum fragments of cytokeratin 19 which are also expressed in SCLC with or without neurofilaments. The aim of this study was to evaluate the diagnostic performance and prognostic role of the two markers in SCLC and their contribution to chemotherapy monitoring and patient follow-up. We studied 62 patients with pathologically proven SCLC: 28 with limited disease (LD) and 34 with extensive disease (ED), and 100 patients with non-malignant pulmonary disease. Immunoradiometric assays (IRMA) were employed to test NSE and CYFRA 21.1 in patients and control subjects. For each patient subset results were expressed as median and interquartile distribution range. NSE and CYFRA 21.1 sensitivity was 0.52 (33/62) and 0.56 (35/62), respectively. In the group of patients with LD, NSE and CYFRA 21.1 sensitivity was 0.42 (12/28) and 0.54 (15/28) and in patients with ED, NSE and CYFRA 21.1 were positive in 0.62 (21/34) and 0.59 (20/34) of cases, respectively. Combining the two markers, a sensitivity of 0.78 (22/28) in LD, 0.82 (28/34) in ED and a global sensitivity of 0.80 (50/62) was obtained. Only NSE was significantly linked to the extension of disease (Mann-Whitney U test p = 0.002) while CYFRA 21.1 did not correlate. The analysis of survival and the evaluation of the two markers at diagnosis showed CYFRA 21.1 to be strongly linked to the patients’ outcome, independently of both clinical prognostic factors and NSE levels (log rank and Cox's model). The markers’ performance during chemotherapy was tested in a group of 33 patients with at least one marker above cut-off. NSE can be considered a reliable marker of tumor mass modifications under chemotherapy, while CYFRA 21.1 expression seems to be relatively independent of tumor volume modifications. An applicable model of biomarkers in SCLC could be the concurrent assay of NSE and CYFRA 21.1 in pre-therapeutic assessment and therapy planning. CYFRA 21.1 does not play an important role during therapy monitoring and follow-up; in these phases NSE alone may be employed.

Point Shear Wave Elastography of the Spleen: Its Role in Patients with Portal Hypertension

The goals of the study described here were to evaluate the feasibility and reproducibility of measuring spleen stiffness (SS) using point shear wave elastography in a series of cirrhotic patients and to investigate whether SS, liver stiffness (LS) and other non-invasive parameters are correlated with the presence of esophagogastric varices (EVs). Fifty-four cirrhotic patients with low-grade EVs or without EVs at esophago-gastro-duodenoscopy were enrolled. They underwent abdominal ultrasound and Doppler ultrasound of hepatic vessels simultaneously with p-SWE of the liver and spleen. In 42 patients, the accuracy of LS and SS, as well as of platelet count and spleen longitudinal diameter, in predicting the presence of EVs was evaluated. The technical success was 90.74% for LS (49/54 patients) and 77.78% for SS (42/54 patients). Inter-observer agreement for SS measurement was high. Both LS and SS correlated with esophago-gastro-duodenoscopy: LS had the highest accuracy in predicting the presence of EVs (area under the receiver operating characteristic curve [AUROC] = 0.913); SS had the lowest accuracy (AUROC = 0.675); platelet count and spleen diameter had intermediate accuracy (AUROC = 0.731 and 0.729, respectively). SS did not have an advantage over LS in predicting low-grade EVs and cannot be proposed as a useful tool in the diagnostic process of cirrhotic patients who require screening esophago-gastro-duodenoscopy.

The Evaluation of Aortic Diameter Changes During Long-Term Follow-Up After Endovascular Treatment of Acute Blunt Traumatic Thoracic Aortic Injuries

Purpose:

To evaluate the variations in aortic diameters and long-term results in patients who underwent thoracic endovascular aortic repair (TEVAR) for acute blunt traumatic thoracic aortic injuries (BTTAIs).

Materials and Methods:

We retrospectively evaluated 23 patients with a mean age of 39 years (range: 17-74 years) who underwent TEVAR for BTTAI between October 2000 and November 2014. All of the patients underwent computed tomography angiography (CTA) before hospital discharge as a baseline imaging for the subsequent follow-up examinations. The technical success, overall survival, and complications were evaluated. Furthermore, the aortic diameters outside of the stent-graft (1 cm proximal and 1 cm distal to the stent-graft) and the aortic diameters within the stent-graft (2 cm distal to the proximal end and 2 cm proximal to the distal end) were assessed. The diameters at baseline on CTA were compared with those of the latest available follow-up examination.

Results:

Technical success was 100% with a mean follow-up of 65.4 months (range: 12-171 months). No death was registered, and 2 (8.7%) of 23 endograft-related complications (1 stent-graft distal infolding and 1 endoleak 2 and 4 months after the procedure, respectively) were observed. An increase in aortic diameter either proximal or distal to the stent-graft (mean value 0.7 and 0.5 mm, respectively) or within the stent-graft (mean value of 0.5 mm for both proximal and distal diameters) was registered (mean follow-up at 65.4 months, range: 12-171 months).

Conclusion:

Aortic dilatation following TEVAR for BTTAI is minimal during long-term follow-up. Endovascular treatment represents a durable and safe option in acute BTTAIs.

A Quantitative Method for the Evaluation of Spatial Resolution in Quality Control of B-mode Ultrasound Images

The work describes a method to quantitatively evaluate spatial resolution in B-mode quality control images as radial modulation transfer function (MTF). The method is easy to use in in-field quality assurance programs in clinical institutions, as it is fast and can be performed with the help of phantoms that are already used for routine quality control. It uses a round insert with different echogenic characteristics compared with the phantom background. The method was automated with a MATLAB® routine, which can be run in full automatic mode or with a grade of interaction by the user, as is sometimes necessary with low-quality images. Radial MTF was evaluated for several ultrasound (US) images produced with different clinical US scanners from various vendors and equipped with different types of transducers (linear, convex, sector, vector) working at various frequencies (from 2 to 14 MHz) and with different modalities. It was also evaluated on various computed tomography (CT) images including round inserts. This was done to compare these results with the MTF calculated from the same images using the well-known method from the point spread function (PSF) of a high-contrast bead. Our radial MTF method, adapted to the specific characteristics of US images, was found to be reasonably robust and in line with other methods commonly used for USs (e.g., the pin method, which has repeatability issues) and in other fields, such as X-ray CT.

Nonenhanced MRI Planning for Endovascular Repair of Abdominal Aortic Aneurysms: Comparison With Contrast-Enhanced CT Angiography

BACKGROUND

To assess whether noncontrast-enhanced magnetic resonance imaging (NC-MRI) is an alternative to contrast-enhanced computed tomography angiography (CTA) for aortoiliac measurements before endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

This study encompasses 30 patients admitted for elective EVAR (27 men and 3 women). Two expert readers (vascular radiologist and vascular surgeon) reviewed CTA images in consensus and chose the proper endograft for each patient. Subsequently, a vascular radiologist and a resident radiologist (observer 1 and 2) reviewed CTA and NC-MRI examinations in a double-blind way and completed standard measurements. The interobserver and intermodality agreement was calculated by intraclass correlation coefficients (ICCs). Furthermore, the correlation between the endograft size chosen by the first pair and the second pair of observers was evaluated.

RESULTS

Concerning all measurements, no significant difference was found. Both CTA and NC-MRI angiographic measurements showed strong correlation. Interobserver ICCs for CTA and NC-MRI showed ranges of 0.62 to 0.99 (mean: 0.92) and 0.56 to 0.99 (mean: 0.91); intermodality ICCs for observer 1 and 2 showed ranges of 0.64 to 0.99 (mean: 0.92) and 0.56 to 0.99 (mean: 0.92). The CTA and NC-MRI vascular measurements correlated strongly, except for both external iliac artery diameters. The choice of stent size was always the same between the 2 observers; furthermore, graft size was always in agreement with that selected prospectively.

CONCLUSION

Computed tomography angiography remains the standard of reference for EVAR planning; NC-MRI can be an option for patients with contraindications for CTA, in particular those with renal impairment.

Cone beam computed tomography and its image guidance technology during percutaneous nucleoplasty procedures at L5/S1 lumbar level

OBJECTIVE

To demonstrate the feasibility of percutaneous nucleoplasty procedures at L5/S1 level using cone beam CT (CBCT) and its associated image guidance technology for the treatment of lumbar disc herniation (LDH).

MATERIALS AND METHODS

We retrospectively reviewed 25 cases (20 men, 5 women) of LDH at L5/S1 levels. CBCT as guidance imaging was chosen after a first unsuccessful fluoroscopy attempt that was related to complex anatomy (n = 15), rapid pathological changes due to degenerative diseases (n = 7) or both (n = 3). Technical success, defined as correct needle positioning in the target LDH, and safety were evaluated; overall procedure time and radiation dose were registered. A visual analog scale (VAS) was used to evaluate pain and discomfort pre-intervention after 1 week and 1, 3, and 6 months after the procedure.

RESULTS

Technical success was 100 %; using CBCT as guidance imaging the needle was correctly positioned at the first attempt in 20 out of 25 patients. Neither major nor minor complications were registered during or after the procedure. The average procedure time was 11 min and 56 s (range, 9-15 min), whereas mean procedural radiation dose was 46.25 Gy.cm² (range 38.10-52.84 Gy.cm²), and mean fluoroscopy time was 5 min 34 s (range 3 min 40 s to 6 min 55 s). The VAS pain score decreased significantly from 7.6 preoperatively to 3.9 at 1 week, 2.8 at 1 month, 2.1 at 3 months, and 1.6 at 6 months postoperatively.

CONCLUSIONS

CBCT-guided percutaneous nucleoplasty is a highly effective technique for LDH with acceptable procedure time and radiation dose.

Accuracy of Critical Care Pain Observation Tool and Behavioral Pain Scale to assess pain in critically ill conscious and unconscious patients: prospective, observational study

Background

Critically ill patients admitted to intensive care unit (ICU) may suffer from different painful stimuli, but the assessment of pain is difficult because most of them are almost sedated and unable to self-report. Thus, it is important to optimize evaluation of pain in these patients. The main aim of this study was to compare two commonly used scales for pain evaluation: Critical Care Pain Observation Tool (CPOT) and Behavioral Pain Scale (BPS), in both conscious and unconscious patients. Secondary aims were (1) to identifying the most relevant parameters to determine pain scales changes during nursing procedures, (2) to compare both pain scales with visual analog scale (VAS), and (3) to identify the best combination of scales for evaluation of pain in patients unable to communicate.

Methods

In this observational study, 101 patients were evaluated for a total of 303 consecutive observations during 3 days after ICU admission. Measurements with both scales were obtained 1 min before, during, and 20 min after nursing procedures in both conscious (n.41) and unconscious (n.60) patients; furthermore, VAS was recorded when possible in conscious patients only. We calculated criterion and discriminant validity to both scales (Wilcoxon, Spearman rank correlation coefficients). The accuracy of individual scales was evaluated. The sensitivity and the specificity of CPOT and BPS scores were assessed. Kappa coefficients with the quadratic weight were used to reflect agreement between the two scales, and we calculated the effect size to identify the strength of a phenomenon.

Results

CPOT and BPS showed a good criterion and discriminant validity (p < 0.0001). BPS was found to be more specific (91.7 %) than CPOT (70.8 %), but less sensitive (BPS 62.7 %, CPOT 76.5 %). COPT and BPS scores were significantly correlated with VAS (p < 0.0001). The combination of BPS and CPOT resulted in better sensitivity 80.4 %. Facial expression was the main parameter to determine pain scales changes effect size = 1.4.

Conclusions

In critically ill mechanically ventilated patients, both CPOT and BPS can be used for assessment of pain intensity with different sensitivity and specificity. The combination of both BPS and CPOT might result in improved accuracy to detect pain compared to scales alone.

Trial registration

NCT01669486

ON-FIELD EVALUATION OF OPERATOR LENS PROTECTIVE DEVICES IN INTERVENTIONAL RADIOLOGY

The recent publication of the Euratom Directive 2013/59, adopting the reduction of eye lens dose limits from 150 to 20 mSv y^-1, calls for the development of new tools and methodologies for evaluating the eye lens dose absorbed by the medical staff involved in interventional radiology practices. Moreover, the effectiveness of the protective devices, like leaded glasses, which can be employed for radiation protection purposes, must be tested under typical exposure scenarios. In this work, eye lens dose measurements were carried out on an anthropomorphic phantom simulating a physician bound to perform standard interventional neuroradiology angiographic procedures. The correlation between eye lens doses, in terms of Hp(0.07), and the equivalent dose [again in terms of Hp(0.07)] monthly measured with thermoluminescent dosemeters placed above the lead apron at the chest level was studied, in the presence and in the absence of different types of leaded glasses.

Evaluation of tablet ultrasound for routine abdominal interventional procedures

AIM

The aim of the study was to establish if a novel tablet ultrasound (US) may replace a high-end US machine during routine interventional radiology activities.

MATERIALS AND METHODS

Thirty consecutive patients were evaluated by two operators comparing the performance of the new US tablet system (VISIQ, Philips Healthcare) against a high-end US system (iU22, Philips Healthcare) using a curved probe (C5-2). A structured questionnaire was used to rank on a 4-point scale the ability of each system to locate a target as detected by previous examinations and visualize needles and path during an interventional procedure. Necessity for conversion from the tablet US to the high-end US system was registered; body mass index (BMI) was annotated for each patient.

RESULTS

Agreement between the operators was found for every patient. Mean patient BMI was 25 (range 17-34). Image quality of the tablet US was considered insufficient in 1 case to visualize the target and in another case to visualize the needle. Mean target image quality was superior with the high-end US system, while needle visibility scored higher with the tablet US. Conversion to the high-end system was registered in 40 % of cases: in most cases (66.6 %) the decision was due to the absence of a dedicated needle guide for the tablet US.

CONCLUSIONS

The novel tablet US was found to provide sufficient image quality for the majority of routine interventional procedures. Dedicated accessories and additional experience with this new generation US device may be needed to replace bulky high-end US systems.

Comparison of cone-beam CT-guided and CT fluoroscopy-guided transthoracic needle biopsy of lung nodules

PURPOSE

To compare the diagnostic performance of cone-beam CT (CBCT)-guided and CT fluoroscopy (fluoro-CT)-guided technique for transthoracic needle biopsy (TNB) of lung nodules.

METHODS

The hospital records of 319 consecutive patients undergoing 324 TNBs of lung nodules in a single radiology unit in 2009-2013 were retrospectively evaluated. The newly introduced CBCT technology was used to biopsy 123 nodules; 201 nodules were biopsied by conventional fluoro-CT-guided technique. We assessed the performance of the two biopsy systems for diagnosis of malignancy and the radiation exposure.

RESULTS

Nodules biopsied by CBCT-guided and by fluoro-CT-guided technique had similar characteristics: size, 20 ± 6.5 mm (mean ± standard deviation) vs. 20 ± 6.8 mm (p = 0.845); depth from pleura, 15 ± 15 mm vs. 15 ± 16 mm (p = 0.595); malignant, 60% vs. 66% (p = 0.378). After a learning period, the newly introduced CBCT-guided biopsy system and the conventional fluoro-CT-guided system showed similar sensitivity (95% and 92%), specificity (100% and 100%), accuracy for diagnosis of malignancy (96% and 94%), and delivered non-significantly different median effective doses [11.1 mSv (95 % CI 8.9-16.0) vs. 14.5 mSv (95% CI 9.5-18.1); p = 0.330].

CONCLUSION

The CBCT-guided and fluoro-CT-guided systems for lung nodule biopsy are similar in terms of diagnostic performance and effective dose, and may be alternatively used to optimize the available technological resources.

KEY POINTS

• CBCT-guided and fluoro-CT-guided lung nodule biopsy provided high and similar diagnostic accuracy. • Effective dose from CBCT-guided and fluoro-CT-guided lung nodule biopsy was similar. • To optimize resources, CBCT-guided lung nodule biopsy may be an alternative to fluoro-CT-guided.

The role of endovascular treatment of pelvic fracture bleeding in emergency settings

PURPOSE

To evaluate the role of endovascular treatment for controlling haemorrhage in haemodynamically unstable patients with pelvic bone fractures and to relate clinical efficacy to pre-procedural variables.

MATERIALS AND METHODS

From March 2009 through April 2013, 168 patients with major pelvic trauma associated with high-flow haemorrhage were referred to our emergency department and were retrospectively reviewed. Pelvic arteries involved were one or more per patient. Embolisation was performed using various materials (micro-coils, Spongostan, plug, glue, covered stent), and technical success, complications, treatment success, clinical efficacy, rebleeding, and mortality rates were assessed. Factors influencing clinical efficacy were also evaluated.

RESULTS

The technical success rate was 100%; no complications occurred during the procedures. Treatment was successful in 94.6% cases, and clinical efficacy was 85.7%. Three patients had to undergo a second arteriography due to recurrent haemorrhage. Fifteen patients died. Pre-embolisation transfusion demand was significantly associated with clinical efficacy.

CONCLUSIONS

Percutaneous embolisation of pelvic bleeding may be considered a safe, effective, and minimally invasive therapeutic option. As haemodynamic stability is the first objective with traumatic haemorrhagic patient, arterial embolisation can assume a primary role. On the basis of our results, pre-procedural transfusion status may be considered a prognostic factor.

KEY POINTS

• The series presented is one of the largest in a single centre. • Arterial embolisation is a life-saving procedure in patients with pelvic haemorrhage. • In pelvic traumas associated with haemorrhage, prognosis is dependent upon prompt treatment. • Transfusion status is significantly related to clinical efficacy.

Ultrasound-guided alcohol injection for Morton's neuroma

BACKGROUND

Ultrasonography-guided alcohol injection (USGAI) of Morton's neuroma represents an alternative to operative treatment. Nonetheless, the literature only reports few small studies evaluating the effectiveness of the treatment. The aim of the present retrospective study was to assess the effectiveness of USGAI to treat Morton's neuroma in 508 patients at 2 medical centers.

METHODS

Between January 2001 and January 2012, 508 patients with 540 Morton's neuroma had USGAI for Morton's neuroma. Only second and third web-space neuromas were included in this study.

RESULTS

A mean number of 3.0 (range, 1 to 4) injections were performed for each neuroma. Mean local inflammatory reaction was 0.7 (range, 0 to 2). There were no other local or systemic complications. The overall mean pre-USGAI VAS score was 8.7 (range, 6 to 10), while the post-USGAI VAS score at 1 year was 3.6 (range, 0 to 9). The delta VAS between the pre- and post-USGAI was statistically significant (P < .0001). At 1-year follow-up 74.5% of patients were satisfied with the procedure.

CONCLUSION

USGAI produced encouraging results in over 500 patients affected by Morton's neuroma. The procedure proved to be safe in all patients.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Evaluation of occupational exposure in magnetic resonance sites

PURPOSE

In an attempt to evaluate the exposure level of magnetic resonance imaging (MRI) workers to static magnetic fields, the isotropic magnetic flux density values were integrated over time to produce the cumulative exposure. To protect occupational staff a further precautionary step is proposed by introducing a weighting function incorporating the limits imposed by the Italian legislation. The results obtained should be reported, at the end of each working day, on a special dose card, in order to record each worker's exposure to the static magnetic field. Moreover, this dose card could be an important tool if long-term effects occur because it provides a complete history of the occupational exposure in an MRI site.

MATERIALS AND METHODS

To conduct measurements, three Hall-sensor probes were used. The consistency of experimental data, tools and methodologies used was evaluated by performing the Kruskal-Wallis test. Finally, the weighted magnitude of the magnetic flux density was integrated over time to obtain global exposure.

RESULTS

Measurements were performed on different MRI scanners ranging from 0.25 up to 3.0 T. The results obtained were compared with the 200 mT·h, which represents the upper limit of the Italian regulation. In no case was the 200 mT·h per day exposure exceeded: however, when the strength of the magnetic field was >200 mT the weighted function overestimated the exposure, so that it represents a highly precautionary measure taking into account possible acute and long-term effects. In addition, from the data recorded during patient positioning operations by MRI staff the dB/dt curve was obtained.

CONCLUSIONS

The areas obtained from the integral of the weighted static magnetic field strength over time can be indicative of the global exposure of the occupational staff. These values should be reported on a special dose card that could be considered as an important tool if long-term effects occur because it provides a complete history of the occupational exposure in an MRI site.

Non-enhanced MR angiography of renal arteries: comparison with contrast-enhanced MR angiography

BACKGROUND

The main causes of renal artery stenosis (RAS) are atherosclerosis and fibromuscular dysplasia. Despite contrast-enhanced magnetic resonance angiography (CE-MRA) being a safe and reliable method for diagnosis of RAS especially in young individuals, recently it has been possible to adopt innovative technologies that do not require paramagnetic contrast agents.

PURPOSE

To assess the accuracy of steady-state free-precession (SSFP) non-contrast-enhanced magnetic resonance angiography (NC-MRA) by using a 1.5 T MR scanner for the detection of renal artery stenosis, in comparison with breath-hold CE-MRA as the reference standard.

MATERIAL AND METHODS

Sixty-three patients (33 men, 30 women) with suspected renovascular hypertension (RVHT) were examined by a 1.5T MR scanner; NC-MRA with an electrocardiography (ECG)-gated SSFP sequence was performed in 58.7% (37/63) of patients; in 41.3% (26/63) of patients a respiratory trigger was used in addition to cardiac gating. CE-MRA, with a three-dimensional gradient echo (3D-GRE) T1-weighted sequence, was performed in all patients within the same session. Maximum intensity projection (MIP) image quality, number of renal arteries, and the presence of stenosis were assessed by two observers (independently for NC-MRA and together for CE-MRA). The agreement between NC-MRA and CE-MRA as well as the inter-observer reproducibility were calculated with Bland-Altman plots.

RESULTS

MIP image quality was considered better for NC-MRA. NC-MRA identified 143 of 144 (99.3%) arteries detected by CE-MRA (an accessory artery was not identified). Fourteen stenoses were detected by CE-MRA (11 atherosclerotic, 3 dysplastic) with four of 14 (28.5%) significant stenosis. Bland-Altman plot demonstrated an excellent concordance between NC-MRA and CE-MRA; particularly, the reader A evaluated correctly all investigated arteries, while over-estimation of two stenoses occurred for reader B. Regarding NC-MRA, inter-observer agreement was excellent.

CONCLUSION

NC-MRA is a valid alternative to CE-MRA for the assessment of renal arteries.

Slice-thickness evaluation in CT and MRI: an alternative computerised procedure

PURPOSE

The efficient use of computed tomography (CT) and magnetic resonance imaging (MRI) equipment necessitates establishing adequate quality-control (QC) procedures. In particular, the accuracy of slice thickness (ST) requires scan exploration of phantoms containing test objects (plane, cone or spiral). To simplify such procedures, a novel phantom and a computerised LabView-based procedure have been devised, enabling determination of full width at half maximum (FWHM) in real time.

MATERIALS AND METHODS

The phantom consists of a polymethyl methacrylate (PMMA) box, diagonally crossed by a PMMA septum dividing the box into two sections. The phantom images were acquired and processed using the LabView-based procedure.

RESULTS

The LabView (LV) results were compared with those obtained by processing the same phantom images with commercial software, and the Fisher exact test (F test) was conducted on the resulting data sets to validate the proposed methodology.

CONCLUSIONS

In all cases, there was no statistically significant variation between the two different procedures and the LV procedure, which can therefore be proposed as a valuable alternative to other commonly used procedures and be reliably used on any CT and MRI scanner.

Matrix-induced autologous chondrocyte implantation of the knee: mid-term and long-term follow-up by MR arthrography

OBJECTIVE

To define magnetic resonance (MR) arthrography imaging findings of matrix-induced autologous chondrocyte implantation (MACI) grafts of the knee in order to describe implant behaviour and to compare findings with validated clinical scores 30 and 60 months after MACI implant.

MATERIALS AND METHODS

Thirteen patients were recruited (10 male, 3 female) with a total number of 15 chondral lesions. Each patient underwent an MACI procedure and MR arthrography 30 and 60 months after surgery. MR arthrography was performed using a dedicated coil with a 1.5-Tesla unit. The status of the chondral implant was evaluated with the modified MOCART scoring scale. The lining of the implant, the integration to the border zone, the surface and structure of the repaired tissue were assessed, and the presence of bone marrow oedema and effusion was evaluated. For clinical assessment, the Cincinnati score was used.

RESULTS

At 60 months, the abnormality showed worsening in 1 out of 15 cases. Integration showed improvement in 3 out of 15 cases, and worsening in 3 out of 15 cases. Two surfaces of the implant showed further deterioration at 60 months, and 1 afflicted implant fully recovered after the same time interval. Implant contrast enhancement at 30 months was seen in 2 out of 15 cases, 1 of which recovered at 60 months. According to the MOCART score, 4 cases were rated 68.4 out of 75 at 30 months and 65 out of 75 at 60 months. The mean clinical score decreased from 8.6 out of 10 at 30 months to 8.1 out of 10 at 60 months.

CONCLUSION

Magnetic resonance arthrography improved the evaluation of implants and facilitated the characterisation of MACI integration with contiguous tissues. The follow-up showed significant changes in MACI, even at 60 months, allowing for useful long-term MR evaluations.

In vitro evaluation of an active heat-and-moisture exchanger: the Hygrovent Gold

BACKGROUND

To improve the heat and humidification that can be achieved with a heat-and-moisture exchanger (HME), a hybrid active (ie, adds heat and water) HME, the Hygrovent Gold, was developed. We evaluated in vitro the performance of the Hygrovent Gold.

METHODS

We tested the Hygrovent Gold (with and without its supplemental heat and moisture options activated), the Hygrobac, and the Hygrovent S. We measured the absolute humidity, using a test lung ventilated at minute volumes of 5, 10, and 15 L/min, in normothermic (expired temperature 34 degrees C) and hypothermic (expired temperature 28 degrees C) conditions. We also measured the HMEs' flow resistance and weight after 24 h and 48 h.

RESULTS

In its active mode the Hygrovent Gold provided the highest absolute humidity, independent of minute volume, in both normothermia and hypothermia. The respective normothermia and hypothermia absolute humidity values at 10 L/min were 36.3 + 1.3 mg/L and 27.1 + 1.0 mg/L with the active Hygrovent Gold, 33.9 + 0.5 mg/L and 24.2 + 0.8 mg/L with the passive Hygrovent Gold, 33.8 + 0.56 mg/L and 24.4 + 0.4 mg/L with the Hygrobac, and 33.9 + 0.8 mg/L and 24.6 + 0.6 mg/L with the Hygrovent S. The efficiency of the tested HMEs did not change over time. At 24 h and 48 h the increase in weight and flow resistance was highest in the active Hygrovent Gold.

CONCLUSIONS

The passive Hygrovent Gold provided adequate heat and moisture in normothermia, but the active Hygrovent Gold provided the highest humidity, in both normothermia and hypothermia.

Post-radiofrequency ablation syndrome after percutaneous radiofrequency of abdominal tumours: one centre experience and review of published works

The aim of this study was to evaluate prospectively post-radiofrequency ablation (RFA) syndrome and to determine its effect on the quality of life in the 15 days after percutaneous RFA treatment. We carried out an internal review board-approved prospective study of the delayed symptoms that occurred after 71 consecutive RFA sessions in 53 patients (12 women and 41 men; age range 45-83 years; mean age 71.6 years) with 45 primary liver tumours, 34 liver metastases, 3 renal cell carcinoma (RCC), 2 residual lesions from RCC after nephrectomy and 1 pancreatic metastases from RCC. Postablation symptoms occurred in 17 of 53 (32%) patients. Six of 17 patients developed low-grade fever (from 37.5 to 38.5 degrees C). Other symptoms included delayed pain (9/17), nausea (7/17), vomiting (3/17), malaise (3/17) and myalgia (1). Postablation syndrome is a common phenomenon after RFA of solid abdominal tumours. Not only in our study but also in the previous ones the occurrence is observed in approximately one-third patients. Patients should be informed that these symptoms are self-limiting after RFA and most patients should be able to resume near-complete preprocedural levels of activity within 10 days after the procedure.

Direct primary or secondary percutaneous ureteral stenting: what is the most compliant option in patients with malignant ureteral obstructions?

The objective of this study was to analyze three ureteral stenting techniques in patients with malignant ureteral obstructions, considering the indications, techniques, procedural costs, and complications. In the period between June 2003 and June 2006, 45 patients with bilateral malignant ureteral obstructions were evaluated (24 males, 21 females; average age, 68.3; range, 42-87). All of the patients were treated with ureteral stenting: 30 (mild strictures) with direct stenting (insertion of the stent without predilation), 30 (moderate/severe strictures) with primary stenting (insertion of the stent after predilation in a one-stage procedure), and 30 (mild/moderate/severe strictures with infection) with secondary stenting (insertion of the stent after predilation and 2-3 days after nephrostomy). The incidence of complications and procedural costs were compared by a statistical analysis. The primary technical success rate was 98.89%. We did not observe any major complications. The minor complication rate was 11.1%. The incidence of complications for the various techniques was not statistically significantly. The statistical analysis of costs demonstrated that the average cost of secondary stenting (637 euros; SD, 115 euros) was significantly higher than that of procedures which involved direct or primary stenting (560 euros; SD, 108 euros). We conclude that one-step stenting (direct or primary) is a valid option to secondary stenting in correctly selected patients, owing to the fact that when the procedure is performed by expert interventional radiologists there are high technical success rates, low complication rates, and a reduction in costs.

Prognostic and biological significance of cytokeratin 19 in pancreatic endocrine tumours

AIM

The prognosis of well-differentiated pancreatic endocrine tumours (PETs) is difficult to establish on a histological basis. The expression of cytokeratin (CK19) has recently been proposed as an indicator of unfavourable outcome. However, this finding still needs to be verified and to be compared with more frequently used prognosticators such as proliferative indices, vascular and/or perineural invasion. The aim of this study was to evaluate the prognostic value of CK19 expression in PETs.

METHODS AND RESULTS

One hundred and forty-five PETs were studied using two different anti-CK19 monoclonal antibodies (BA17 and RCK108). The results were statistically compared with proliferation markers, vascular and perineural invasion and the presence of metastases. On univariate analysis, CK19 immunoreactivity correlated with prognosis only when it was detected with the RCK108 antibody and only in the whole group of PETs and in insulinomas. Conversely, it did not predict survival in non-functioning neoplasms. Ki67 index, mitotic count, vascular and perineural invasion were all statistically correlated with prognosis. On multivariate analysis, only the Ki67 index and metastases were independent prognosticators.

CONCLUSIONS

CK19 expression correlates with patient survival only when detected with the RCK108 antibody and mainly in insulinomas. Ki67 index and metastases represent the only two independent predictors of survival.

Preliminary evaluation of the performance of a new, highly sensitive commercial immunoassay for serum ferritin determination

We evaluated the analytical performance of a new, commercial, fully automated immunoturbidimetric assay for the determination of ferritin [FER-Latex(X2)CN SEIKEN, Denka Seiken, Japan] in serum on the Olympus AU2700 analyzer. The new assay is a latex-enhanced turbidimetric immunoassay with an analysis time of 10 min. The linearity of the assay was confirmed up to 2505 pmol/L (R2=0.999). The detection limit and the functional sensitivity were both 4.5 pmol/L. The intra- and inter-assay imprecision (CV) at 67, 506, 2186 pmol/L was < 1.8% and < 2.5%, respectively. Verification of the traceability to a WHO standard (80/578) showed a recovery of 102.6% (target value 449 pmol/L). No hook effect was observed in samples containing up to 33,705 pmol/L. The assay showed good correlation with the Beckman Immage nephelometric system (r=0.999). Hemoglobin (< or = 9.8 g/L), total bilirubin (< or = 113 micromol/L), conjugated bilirubin (< or = 109 micromol/L) and rheumatoid factor (< or = 5.2x10(5) IU/L) did not interfere with the assay. The reference interval (2.5-97.5 percentile) was 72-521 pmol/L for men and 27-267 pmol/L for women. The reference interval in patients with anemia, malignant tumors and hemochromatosis was 5.6-52, 130-2436 and 1465-2903 pmol/L, respectively. On the basis of the receiver operating characteristic curve, the 90% sensitivity cut-off value to distinguish between patients with and without iron deficiency was 40 pmol/L. The new latex turbidimetric procedure for ferritin assay is an attractive alternative that avoids the need for dedicated instrumentation.

Intratumour T cells, their activation status and survival in gastric carcinomas characterised for microsatellite instability and Epstein-Barr virus infection

Gastric carcinomas (GCs) with high microsatellite instability (MSI) or an Epstein-Barr virus (EBV) infection are prevalently poorly differentiated adenocarcinomas with abundant lymphoid infiltration. The aims of the study were to clarify (1) if tumour-infiltrating lymphocytes (TILs) and cytotoxic-activated TILs are associated with a better clinical outcome in patients with GCs characterised for the presence of MSI and EBV; (2) if the nature and the activation status of TILs are involved in tumour cell apoptosis, evaluated using the M30 antibody, directed against a fragment of cytokeratin-18 caspase-cleaved during early steps of epithelial cell apoptosis. The immunophenotype of TILs and the tumour cell apoptosis were analysed with immunohistochemistry in 96 GCs, including 35 MSI GCs, and 61 GCs without MSI [microsatellite stable (MSS)], 17 of which were EBV+. MSI and MSS/EBV+ GCs displayed a significantly higher mean number of cytotoxic-activated TILs and apoptotic tumour cells than MSS/EBV- GCs (CD8+ TILs/HPF, 21.7 and 69.6 vs 6.4; T-cell intracellular antigen (TIA)-1+ TILs/HPF, 16.7 and 32.05 vs 5.2; granzyme B+ TILs/HPF, 7.5 and 8.6 vs 0.8; perforin+ TILs/HPF, 5.9 and 9.2 vs 0.9; and M30 IR tumour cells, 5.9 and 2.9 vs 2.3%). In addition to the most reliable clinico-pathological parameters (lymph node status, depth of tumour invasion and tumour stage), a univariate analysis showed that the presence of CD3+ TILs higher than 14.9 (p=0.01), CD8+ TILs higher than 9.5 (p<0.05) and MSI (p=0.02) were associated with better overall patient survival. Using a Cox regression model, only a high number of CD3+ TILs (p=0.02) and a low tumour stage (p=0.00001) were identified as independent prognostic factors. In conclusion, our study demonstrates that a high number of CD3+ and CD8+ TILs is a characteristic of MSI- and EBV-associated GCs and represents a favourable prognostic factor, independently of the pathogenesis of GCs.

Gastroesophageal reflux disease in infants: how much is predictable with questionnaires, pH-metry, endoscopy and histology?

Symptoms of gastroesophageal reflux disease (GERD) are common in infants. It is often difficult to discriminate between physiological and pathologic gastroesophageal reflux, although this discrimination is essential to determine which infants to evaluate and treat.

OBJECTIVES

To identify the prevalence of reflux symptoms in infants and to evaluate the predictive value of a questionnaire and the correlation between pH study, histology and clinical score.

METHODS

Parents of 100 unselected infants visiting the well-baby clinic and 100 infants suspected of having gastroesophageal reflux disease were asked to fill in a 35-item questionnaire. A validated score, the Orenstein I-GERQ, was applied for selected questions. All infants suspected of having gastroesophageal reflux disease underwent prolonged esophageal pH monitoring and 44 or 100 underwent upper gastrointestinal tract endoscopy with esophageal biopsy.

RESULTS

Parents of infants with suspected gastroesophageal reflux disease reported significantly more regurgitation (68% versus 45%, P < 0.05) and crying (51% versus 20%, P < 0.01) compared with the parents of healthy infants. A pathologic pH study (reflux index > 10%) was found in 21 of 100 (21%) infants and was significantly associated only with pneumonia, apnea with fussing (P = 0.013 for both), defecation less than once a day (P = 0.033) and constipation (P = 0.05). Esophagitis was present in 17 of 44 (39%) and no one question was found to be significantly predictive. 38% of infants with a pathologic pH study had a normal esophageal biopsy and 53% of infants with histologic esophagitis had a normal pH study. Discordance between pH study and biopsies occurred in 14 of 44 (32%) patients. The Orenstein I-GERQ cut-off score failed to identify eight of 31 (26%) infants with gastroesophageal reflux disease. Conversely, the score was positive in 17 of 22 (81%) infants with normal biopsy and pH study and in 14 of 47 (30%) infants with normal pH study.

CONCLUSIONS

Clinical symptoms, histology and pH study show poor correlation in infants. Clinical symptoms such as regurgitation and crying are less frequent in unselected infants than in infants suspected of gastroesophageal reflux disease. However, questionnaires are poorly predictive for the severity of gastroesophageal reflux disease, as they do not correlate with esophageal acid exposure as measured by pH-metry and with esophagitis as evaluated by histology of esophageal biopsies.

Radiochromic film measurement of anisotropy function for high-dose-rate Ir-192 brachytherapy source

The dose distribution produced by the high-dose-rate (HDR) 192Ir source is inherently anisotropic due to self-absorption by the high-density source core, oblique filtration by the source capsule and the asymmetric geometry of the source capsule. To account for the dose distribution anisotropy of brachytherapy sources, AAPM Task Group No 43 has included a two-dimensional anisotropy function, F(r, theta), in the recommended dose calculation formalism. Gafchromic HS radiochromic film (RCF) was used to measure anisotropy function for microSelectron HDR 192Ir source (classic/old design). Measurements were carried out in a water phantom using specially fabricated PMMA cylinders at radial distances 1, 2, 3, 4 and 5 cm. The data so generated are comparable to both experimental and Monte Carlo calculated values for this source reported earlier by other authors. The RCF method described in this paper is comparatively high resolution, simple to use and is a general method, which can be applied for other brachytherapy sources as well.

In vitro analysis of ultrasound second generation contrast agent diluted in saline solution

PURPOSE

To evaluate the changes in response of a second-generation sonographic contrast agent diluted in saline solution at different concentrations when different scanning techniques, and saline solution temperatures and pH were used.

MATERIALS AND METHODS

A series of tests was devised to analyse the behaviour of the sonographic contrast agent at different concentrations, temperatures, pH and scanning techniques. Latex balloons were used as phantoms. These were filled with 0.9% Sodium Chloride solution mixed with a suspension of sulphur hexafluoride microbubbles stabilised with phospholipids (SonoVue ) and scanned with the harmonic imaging technique at low acoustic pressure. For each image obtained, we calculated the mean grey-scale level values and the standard deviations of grey-scale level were calculated within a ROI on the US images obtained; the resulting data were used to create echogenicity curves of UCA the echo-enhancer over time at the different conditions tested.

RESULTS

We noted that SonoVue maintains adequate backscatter properties even at low concentration (0.15%) in N/S solution. The amount of echogenicity can be considered adequate for the average duration of an ultrasound examination. These properties are not affected by the scanning technique used on the phantom containing the UCA contrast agent/NaCl solution. The pH of the saline solution does not affect the survival of the microbubbles. Temperature becomes a significant value beyondover 33-37 degrees C; this condition favours rupture of the microbubbles with subsequent reduction of the echogenicity after 10-15 min, and complete disappearance after 30 min. US beam attenuation related to the concentration of the microbubbles in the saline solution volume has a non-linear behaviour; at low amplification levels, attenuation becomes more significant when using SonoVue concentrations higher than 0.4%. Unexpected greater improvement in US beam transmission was experienced for each of the three SonoVue concentrations tested, and especially for 0.2% and 0.4%, compared to saline solution alone.

CONCLUSIONS

Our results show that a second-generation contrast agent may be used even diluted at low concentration in saline solution. This characteristic opens up new diagnostic perspectives possibilities for the use of contrast-enhanced harmonic imaging; in particular, its can be suggested used in hollow organs and functional studies. These in vitro results require by confirmation by clinical applications which are under evaluation and experimentation.

Microvessel density in prostate carcinoma

The objective of this work was to assess the correlation between microvessel density (MVD), pathological stage and disease recurrence in a series of patients who underwent radical prostatectomy for prostate cancer. Pathological material from 75 consecutive radical prostatectomies performed before 1994 without neo-adjuvant treatment, in which sufficient follow-up data were available, was re-examined. Paraffin embedded material was re-cut and hematoxylin and eosin (H&E) stained. Areas of maximal angiogenesis within tumor were identified. Expression of CD34 was investigated by using the monoclonal antibody MY 10. Within the areas of maximal angiogenesis, microvessels expressing CD34 were counted and specimens were divided into two groups, one showing a count of less than 90 microvessels per microscopic field at 200 x magnification (MVD<90), the second more than 90 microvessels (MVD>90). The MVD was then related to pathological stage, Gleason score (GS) and outcome of the disease. Mean follow-up was 84 months. Clinical or biochemical progression was observed in 38.6% of patients. In low GS cases, MVD was always <90, whereas in GS 5-6, half had MVD <90 and half were >90. In high GS MVD was always >90. MVD was positively associated with a higher pathological stage. Progression of the disease was observed in 20% of MVD <90 and in 51% in MVD >90 (P=0.006). Mantel-Haensz test showed a correlation between MVD and time to progression (P<0.05). Although problems exist in methods of counting and in the cut-off number of vessels, which can discriminate the risk categories, it may be concluded that microvessel counts, using CD34 monoclonal antibody, can accurately predict the outcome of radical prostatectomy.

A new method to assess the fluidodynamic behaviour of an angiographic contrast agent

PURPOSE

To propose a new method for the assessment of the fluidodynamic behaviour of angiographic contrast agents. The method enables measurement of the spatial distribution and time dependence of the contrast agent along a pseudo-vessel on images obtained with an X-ray image intensifier.

MATERIAL AND METHODS

A particular phantom was devised consisting of a plexiglas box with an insert into which a latex tube with a 0.4 cm in diameter was placed in order to simulate the tortuous flow of a blood vessel. The box, which is filled with water to simulate the thickness of a normal patient, is connected to an injection and pumping system which serve to keep the contrast agent flowing in the pseudo-vessel tube. The pseudo-vessel tube was filled with plain water in one case and with saline solution in another case to assess their different dilution capabilities. The phantom and the flow of contrast agent were imaged with a conventional X-ray image intensifier system and the images were stored in digital format during 35 second acquisitions at a speed of 4 frames per second; for any frame it is possible to measure the mathematical contrast in any position in the image. Further, a diagram showing the time dependence of the spatial distribution of the mathematical contrast is proposed. The X axis shows the spatial distribution of the mathematical contrast, whereas the Y axis shows its temporal variation with a gray level proportional to the mathematical contrast value. By building an horizontal profile of this diagram one can obtain the spatial distribution at a fixed time, while by building a vertical profile one can obtain the temporal variation at a fixed point. Several different contrast agents were so tested.

RESULTS

The proposed method allows different fluido-dynamic behaviour patterns of contrast agents and flowing media to be shown. Owing to the different chemical characteristics of water and saline solution these media have different dilution capabilities (higher for water) and this is well demonstrated by the diagram profiles obtained for each. The system has also allowed the detection of a particular behaviour of some contrast agents, whose spatial distribution was non uniform even in the last frames, thus showing a tendency to maintain their bolus-nature over time. An interesting feature which can be noticed in all the temporal profiles is the presence of a "pre-bolus", i.e. the contrast is higher at the very beginning of the flow, then decreases and after some time starts to increase again. Though the initial contrast value obviously depends on the iodine concentration employed, the method shows the contrast variation as a function of time is different for different contrast agents.

CONCLUSIONS

The method and the equipment proposed provide a good description of the fluidodynamic behaviour of different contrast agents, but do not constitute a reference method for testing haemodynamic behaviour which, "in vivo", is obviously affected by several other chemical and metabolic factors. However, the method allows evaluation of the contrast agents from a physical and fluidodynamic point of view, showing that the iodine content is not the only feature affecting their behaviour. The method can be used in quality control to test the constancy of the physical behaviour of different contrast agents.

Patient effective dose from endovascular brachytherapy with 192Ir sources

The growing use of endovascular brachytherapy has been accompanied by the publication of a large number of studies in several fields, but few studies on patient dose have been found in the literature. Moreover, these studies were carried out on the basis of Monte Carlo simulation. The aim of the present study was to estimate the effective dose to the patient undergoing endovascular brachytherapy treatment with 112Ir sources, by means of experimental measurements. Two standard treatments were taken into account: an endovascular brachytherapy of the coronary artery corresponding to the activity x time product of 184 GBq.min and an endovascular brachytherapy of the renal artery (898 GBq.min). Experimental assessment was accomplished by thermoluminescence dosemeters positioned in more than 300 measurement points in a properly adapted Rqndo phantom. A method has been developed to estimate the mean organ doses for all tissues and organs concerned in order to calculate the effective dose associated with intravascular brachytherapy. The normalised organ doses resulting from cronary treatment were 2.4 x 10(-2) mSv.GBq(-1).min(-1) for lung, 0.9 x 10(-2) mSv.GBSq(-1).min(-1) for oesophagus and 0.48 x 10(-2) mS.GBq(-1).min(-1) for bone marrow. During brachytherapy of the renal artery, the corresponding normalised doses were 4.2 x 10(-2) mS.GBq(-1).min(-1) for colon, 7.8 x 10(-2) mSv.GBq(-1).min(-1) for stomach and 1.7 x 10(-2) mSv.GBq(-1).min(-1) for liver. Coronary treatment iJnvlled an efl'fective dose of (0.046 mSv.GBq(-1).min(-1), whereas the treatment of the renal artery resulted in an effective dose of 0.15 mSv.GBq(-1).min(-1); there were many similarities with data from former studies. Based on these results it can be concluded that the dose level of patients exposed during brachytherapy treatment is low.

[Feasibility of the use of elastographic techniques with ultrasound in the diferentiation of different tissues]

PURPOSE

To investigate the feasibility of distinguishing different tissues by detecting their different elastic properties when mechanically stimulated with an ultrasound wide beam.

MATERIAL AND METHODS

A tissue-mimicking material phantom was placed in a water filled box. Two devices (Teuco Hydrosonic) emitting two US beams (3.2 MHz) were placed on two opposite walls of the box. The US beams had a circular diameter of about 10 cm; their intensity could be set by varying the power voltage applied to the device from 0 to 12 V. The US beams caused a mechanical stimulation of both the phantom and the water surrounding it. An ATL HDI 5000 scanner was used in order to acquire tissue Color Doppler images using the fundamental frequency (Tissue Doppler Imaging, TDI), and the second harmonic (Harmonic Tissue Doppler Imaging, HTDI). The images allowed to visualize, using a color scale, the vibrational status of both the phantom and the water surrounding it. Both fundamental and second harmonic images were taken using different power values supplied to the stimulation device, with the voltage ranging from 0 to 12 V. In order to quantify the vibrational status of the water and of the tissue-mimicking phantom two Regions Of Interest (ROI) were taken on the images. A parameter describing the "color amount" in each ROI and defined by an appropriate mathematical function was proposed.

RESULTS

Differences between the values of the "color amount" parameter in the phantom and in water were statistically significant both at the fundamental frequency and at second harmonic imaging, and for each positive value of the voltage of the power supplied to the device for the stimulation. Also the differences between the parameter "color amount" at the fundamental frequency and second harmonic imaging were statistically significant; the differences were found for both water and phantom and for any positive voltage. The correlation between the intensity of the stimulation (voltage) and the "color amount" parameter is statistically significant with the second harmonic technique in the phantom, nearly significant with the second harmonic technique in water and not significant in the other cases.

CONCLUSIONS

It is possible to try to characterize a tissue by analyzing its elastic properties when an ultrasound wide beam mechanically stimulates it. The most promising technique consists in acquiring images using Harmonic Tissue Doppler Imaging, (HTDI) and measuring the vibrational status by using the "color amount" parameter proposed.

[Study of ultrasonographic image textures with second-order statistical methods]

BACKGROUND

We report the sonographic image texture of the neonatal heart in different stages of development by calculating numerical parameters extracted from the gray scale cooccurrence matrix. To show pixel values differences and enhance texture structure, images were equalized, and then the gray level range was reduced to 16 to allow for sufficiently high occupancy frequency of the cooccurrence matrix.

MATERIALS AND METHODS

We measured B-mode US images, all acquired with the same unit, using the same setup (gain, frequency, constant TGC). For each case measurements were made on 3 diastolic images by selecting a 32 x 64 pixel on the interventricular septum ROI. This procedure was applied to 3 different examinations made at birth, at 3 days, and after a month of life. For each 8 bit image we obtained a coocurrence matrix by sampling adjacent pixels at 0 degree, from which we calculated entropy; then the images were equalized and converted to 4 bit format; on these processed images we calculated 4 gray scale coocurrence matrix samplings adjacent pixels at angles of 0 degree, 45 degrees, 90 degrees, and 180 degrees. Parameters obtained from different angles cooccurrence matrix were averaged to get a numerical parameter independent of sampling angles.

RESULTS

The one-way analysis of variance and Student's "t"-test were performed on the parameters obtained from 3 different examinations and the differences among different developmental stages are 95% significant. No significance was obtained comparing images at birth with those at 3 days.

CONCLUSIONS

Differences are so little significant that they may be due to different factors affecting image texture and the variability introduced by manual ROI positioning; therefore no definitive conclusions can be drawn as to considering this kind of analysis capable of discriminating different stages of myocardial development. To apply this analysis to routine US examinations, different correction factors for range, azimuth, and focal dependence of texture must be considered.

Radiotherapy Treatment Verification

During a radiotherapy treatment, a dosimetric verification or a geometric localization can be done, in order to assess the quality of the treatment. The dosimetric verification is generally performed measuring the dose at some points inside (natural cavities) or outside the patient, and comparing it to the dose at the same points calculated and predicted by the treatment planning system. This can be done either with thermoluminescent or diodes dosimeters or with ionization chambers. The geometric localization can be done acquiring a portal image of the patient. Portal imaging can be performed either with films placed between metallic screens, or with an electronic portal imaging device such as fluoroscopic systems, solid state devices or matrix ionization chamber systems. In order to assess possible field placement errors, the portal images have to be compared with images obtained with the simulator in the same geometric conditions and/or with the digitally reconstructed radiograph (DRR) obtained with the treatment planning system. In particular, when using matrix ionization chamber systems, the portal images contain also information regarding the exit dose. This means that this kind of imaging device can be used both for geometric localization and for dosimetric verification. In this case, the exit dose measured by the portal image can be compared with the exit dose calculated and predicted by the treatment planning system. Some “in-vivo” applications of this methodology are presented.