Transaneurysmal Occlusion of Complicated Common Femoral Artery Pseudoaneurysms Using the Angio-Seal Closure Device-A Promising Technique.

PURPOSE: Pseudoaneurysm (PSA) developing after catheter examinations is one of the most frequent vascular complications and a nonsurgical technique with utmost low risk of complications is warranted. Our aim was to investigate the technical feasibility, success, and safety of transaneurysmal occlusion of complicated post-interventional common femoral artery (CFA) PSA using the Angio-Seal Closure Device (ASCD) and a technique that we describe as the transaneurysmal (TA) maneuver. MATERIAL AND METHODS: We used the Angio-Seal (Terumo, Tokyo, Japan) Closure System to manage complicated PSAs in patients who would otherwise have needed surgery after failure of all conservative therapies. The TA maneuver was performed in 14 consecutive patients from July 2021 to July 2022. After ultrasound-guided puncture of the PSA close to its neck, the CFA was entered radiographically with micro-guidewires, and the neck of the PSA was closed with the ASCD after changing the sheaths and wires. All patient had to wear a pressure dressing until the next day, when successful closure was verified by sonography. RESULTS: All procedures were performed with technical success and without any complications. No patient had to undergo surgery. All sonographies on the next day confirmed complete absence of perfusion within the PSA and normal flow conditions of the CFA and vessels below. CONCLUSION: The TA maneuver a promising minimally invasive procedure for closing complicated PSA of the CFA after catheter examination.

Splenic artery steal syndrome in patients with orthotopic liver transplant: Where to embolize the splenic artery?

PURPOSE: This study compared proximal and distal embolization of the splenic artery (SA) in patients with splenic artery steal syndrome (SAS) after orthotopic liver transplantation (OLT) regarding post interventional changes of liver function to identify an ideal location of embolization. METHODS AND MATERIALS: 85 patients with SAS after OLT treated with embolization of the SA between 2007 and 2017 were retrospectively reviewed. Periinterventional DSA was used to assess treatment success and to stratify patients according to the site of embolization. Liver function was assessed using following laboratory values: bilirubin, albumin, gamma-glutamyl transferase, glutamat-pyruvat-transaminase (GPT), glutamic-oxaloacetic transaminase (GOT), Alkaline Phosphatase (ALP), aPTT, prothrombin time and thrombocyte count. Descriptive statistics were used to summarize the data. Median laboratory values of pre, 1- and 3-days, as well as 1-week and 1-month post-embolization were compared between the respective embolization sites using linear mixed model regression analysis. RESULTS: All procedures were technically successful and showed an improved blood flow in the hepatic artery post-embolization. Ten Patients were excluded due to re -intervention or inconsistent image documentation. Pairwise comparison using linear mixed model regression analysis showed a significant difference between proximal and distal embolization for GPT (57.0 (IQR 107.5) vs. 118.0 (IQR 254.0) U/l, p = 0.002) and GOT (48.0 (IQR 48.0) vs. 81.0 (IQR 115.0) U/l, p = 0.008) 3-days after embolization as well as median thrombocyte counts 7-days after embolization (122 (IQR 108) vs. 83 (IQR 74) in thousands, p = 0.014). For all other laboratory values, no statistically significant difference could be shown with respect to the embolization site. CONCLUSION: We conclude that long-term outcomes after embolization of the SA in the scenario of SAS after OLT are irrespective of the site of embolization of the SA, whereas a proximal embolization potentially facilitates earlier normalization of liver function. Choice of technique should therefore be informed by anatomical conditions, safety considerations and preferences of the interventionalist.

Biodegradable Polydioxanone Microspheres for Transcatheter Arterial Embolization: Proof of Principle.

PURPOSE: To evaluate feasibility, embolization success, biodegradability, reperfusion, and biocompatibility of biodegradable microspheres (MS) made from polydioxanone (PDO) for transcatheter arterial embolization. MATERIALS AND METHODS: Unilateral selective renal embolization of a segmental artery was performed in 16 New Zealand White rabbits with PDO-MS (100-150 µm and 90-315 µm). Animals were randomly assigned to different observation periods and underwent control digital subtraction angiography (DSA) and MR imaging immediately (n = 3), 1 week (n = 2), 4 weeks (n = 2), 8 weeks (n = 2), 12 weeks (n = 5), and 16 weeks (n = 2) after embolization. Kidneys were harvested for macroscopic and histologic analysis of embolization success, biodegradability, and biocompatibility. RESULTS: Embolization was technically successful in 15 of 16 animals. One animal died of anesthesia-related circulatory failure. The 100-150 µm MS were injected easily through 3-F catheters; the 90-315 µm MS tended to clog with intermittent catheter obstruction. DSA and MR imaging showed successful target embolization in 13 of 15 animals. In 2 animals, the entire kidney was affected owing to catheter clogging, including a reflux of MS while flushing. Control DSA and MR imaging showed increasing vascular reperfusion with time. Macroscopic and histologic analysis revealed necrosis/infarction in areas in which embolization was achieved. MS were extensively degraded after 16 weeks, and overall inflammatory reaction was mild. CONCLUSIONS: Biodegradable PDO-MS induced effective embolization of target vessels while demonstrating good biocompatibility. MS increasingly dissolved at 16 weeks, partial reperfusion started at week 1, and complete reperfusion started at week 8, thus offering possible advantages as a temporary embolic agent.

Novel MR-Visible, Biodegradable Microspheres for Transcatheter Arterial Embolization: Experimental Study in a Rabbit Renal Model.

PURPOSE: To assess feasibility, embolization success, biodegradability, reperfusion, biocompatibility and in vivo visibility of novel temporary microspheres (MS) for transcatheter arterial embolization. MATERIAL AND METHODS: In 9 New Zealand white rabbits unilateral superselective embolization of the lower kidney pole was performed with biodegradable MS made of polydioxanone (PDO) (size range 90-300 and 200-500 µm) impregnated with super-paramagnetic iron oxide (SPIO). Magnetic resonance imaging (MRI) was performed post-interventionally to assess in vivo visibility. Embolization success was assessed on digital subtraction angiography, MRI and gross pathology. One animal was killed immediately after embolization to assess original particle appearance. 8 animals were randomly assigned to different observation periods (1, 4, 8, 12 and 16 weeks), after which control angiography and MRI were obtained to determine recanalization. Histopathological analysis was performed to determine biodegradability and biocompatibility by using dedicated quantitative assessment analysis. RESULTS: Ease of injection was moderate. Embolization was technically successful in 7 of 8 animals, one rabbit received non-selective embolization of the whole kidney and abdominal off-target embolization. Arterial occlusion was achieved in all kidneys, infarct areas in macro- and microscopic analysis confirmed embolization success. Control angiograms showed evidence of partial reperfusion. The microspheres showed extensive degradation over the course of time along with increasing inflammatory response and giant cell formation. SPIO-loaded MS were visible on MRI at all time points. CONCLUSIONS: SPIO-impregnated biodegradable PDO-MS achieved effective embolization with in vivo visibility on MRI and increasing biodegradation over time while demonstrating good biocompatibility, i.e., a physiologically immune response without transformation into chronic inflammation. Further studies are needed to provide clinical applicability.

Renal Denervation by Transaortic Periarterial Ethanol Injection: An Experimental Study in Porcines.

AIMS: To evaluate the feasibility, safety and efficacy of renal sympathetic denervation via endoluminal transaortic periarterial ethanol injection. METHODS AND RESULTS: In 11 normotensive pigs transaortic puncture was performed with a 90-cm 21G needle with subsequent unilateral ethanol injection to the periarterial space. Needle placement was achieved using a 7F steerable sheath fluoroscopically positioned slightly above the renal artery origin. Blood pressure measurements and abdominal CT scans were performed immediately pre- and postintervention and 4 weeks later. After euthanasia norepinephrine concentration of both kidneys (RTNEC) was determined and renal arteries and surrounding tissues histologically examined to assess induced nerve fibre degeneration. RESULTS: All but one procedure were technically successful. One major complication with accidental ethanol injection into the renal artery and subsequent infarction occurred. One pig died from no intervention-related cardiac arrest. The 4-week follow-up was uneventful in the remaining 10 animals. RTNEC was significantly lower on the treated side in eight of ten pigs (mean decrease 36.6%) with correlating histopathological signs of nerve degeneration. CONCLUSIONS: Renal sympathicolysis by transaortic periarterial ethanol injection was feasible and effective in a porcine model. This approach may be an alternative to catheter-based RFA or other methods of renal denervation.

Clinical Experience with Real-Time 3-D Guidance Based on C-Arm-Acquired Cone-Beam CT (CBCT) in Transjugular Intrahepatic Portosystemic Stent Shunt (TIPSS) Placement.

PURPOSE: The aim of this study was to evaluate the feasibility of cone-beam computed tomography (CBCT)-based real-time 3-D guidance of TIPSS placement and its positioning compared to standard guiding methods. MATERIALS AND METHODS: In a prospective, randomized, consecutive study design from 2015 to 2017, we included 21 patients in the CBCT guided group and 15 patients in the ultrasound (US) guided group. The prospective groups were compared in terms of success rate of intervention, portal vein puncture/procedure time, number of puncture attempts and applied dose. We furthermore retrospectively analyzed the last 23 consecutive cases with fluoroscopic guided portal vein puncture in terms of success rate, procedure time and applied dose, as it has been the standard method before US guidance. RESULTS: The median number of puncture attempts (CBCT: n = 2, US: n = 4, p = 0.249) and the mean puncture time (CBCT: 32 ± 45 min, US: 36 ± 45 min, p = 0.515) were not significantly different. There were furthermore no significant differences in the mean time needed for the total TIPSS procedure (CBCT: 115 ± 52 min, US: 112 ± 41 min, fluoroscopy: 110 ± 33 min, p = 0.996). The mean applied dose of the complete procedure also showed no statistically significant differences (CBCT: 563 ± 289 Gy·cm2, US: 322 ± 186 Gy·cm2, fluoroscopy: 469 ± 352 Gy·cm2, p = 0.069). There were no image guidance related complications. CONCLUSION: Real-time 3-D needle guidance based on CBCT is feasible for TIPSS placement. In terms of puncture attempts, duration and dose, CBCT guidance was not inferior to the control groups and may be a valuable support for interventionists in TIPSS procedures.

C-Arm Cone Beam CT for Intraprocedural Image Fusion and 3D Guidance in Portal Vein Embolization (PVE).

PURPOSE: Portal vein embolization (PVE) is applied in patients with extended oncologic liver disease to induce hyperplasia of the future liver remnant and make resection feasible. Ultrasound (US) guidance is the gold standard for percutaneous portal vein access. This study evaluated feasibility and safety of C-arm cone beam computed tomography (CBCT) for needle guidance. MATERIALS AND METHODS: In 10 patients, puncture was performed under 3D needle guidance in a CBCT data set. Contrast-enhanced (CE) CBCT was generated (n = 7), or native CBCT was registered to pre-examination CE-CT via image fusion (n = 3). Technical success, number of punctures, puncture time (time between CBCT acquisition and successful portal vein access), dose parameters and safety were evaluated. For comparison, 10 patients with PVE under US guidance were analyzed retrospectively. Study and control group were matched for age, BMI, INR, platelets, portal vein anatomy. RESULTS: All interventions were technically successful without intervention-related complications. In the study group, the mean number of puncture attempts was 3.1 ± 2.5. Mean puncture time was 12 min (±10). Mean total dose area product (DAP) was 288 Gy cm2 (±154). The mean relative share of CBCT-related radiation exposure was 6% (±3). Intervention times and DAP were slightly higher compared to the control group without reaching significance. CONCLUSION: CBCT-guided PVE is feasible and safe. The relative dose of CBCT is low compared to the overall dose of the intervention. This technique may be a promising approach for difficult anatomic situations that limit the use of US for needle guidance.

Embolization of a life-threatening placenta increta hemorrhage with a four-month MRI follow-up.

A 29-year-old woman with partial placenta increta was treated by bilateral uterine artery embolization (UAE) for bleeding with hemorrhagic shock two months after delivery, resulting in permanent hemostasis. The patient underwent a total of three magnetic resonance imaging (MRI) examinations-before UAE and four days and four months after UAE. At four months, MRI showed a fully regenerated uterus with preserved perfusion and complete resolution of residual placental tissue.

Renal denervation by CT-guided periarterial injection of hyperosmolar saline, vincristine, paclitaxel and guanethidine in a pig model.

AIMS: The aim of the study was to evaluate the feasibility, safety and efficacy of renal sympathetic denervation with CT-guided periarterial injection of potentially neurolytic agents in pigs. METHODS AND RESULTS: Unilateral injection of formulations containing either 5M hyperosmolar saline, vincristine, paclitaxel or guanethidine around the renal artery was performed in 24 normotensive pigs with six animals per group. Needle placement and injections were performed under CT fluoroscopy guidance. Blood pressure measurements and CT scans were performed immediately before and after the intervention and four weeks after treatment. After euthanasia, norepinephrine (NE) concentrations of both kidneys were determined. The renal arteries and surrounding tissue were examined histologically to evaluate nerve fibre degeneration. Procedures were technically successful with good periarterial distribution of the injectant in all but one pig in the guanethidine group. No major adverse events or post-interventional complications occurred. In the vincristine group, NE concentrations of the renal parenchyma were lower on the treated side in all pigs with a mean decrease of 53% (38%-62%, p<0.01) compared to the contralateral control. Correspondingly, histological examination revealed neural degeneration in all animals treated with vincristine. In the other groups, no significant drop of NE values, or histological signs of nerve fibre degeneration were found. CONCLUSIONS: CT-guided periarterial injection of the different substances was feasible and safe. Renal sympathetic denervation was achieved with vincristine. In contrast, hyperosmolar saline, paclitaxel and guanethidine do not seem to be appropriate for renal denervation in a pig model at the dosage used.

MR-guided high-focused ultrasound for renal sympathetic denervation-a feasibility study in pigs.

BACKGROUND: Renal sympathetic denervation has recently gained clinical relevance for the treatment of therapy-resistant hypertension. Denervation is currently mainly performed using catheter-based transarterial radiofrequency ablation of periarterial sympathetic nerve fibers. Since this approach has numerous limitations, we conducted a study to evaluate the feasibility, safety, and efficacy of magnetic resonance-guided high-focused ultrasound (MRgHiFUS) for renal sympathetic denervation in pigs as an alternative to catheter-based ablation. METHODS: Renal periarterial MRgHiFUS was performed under general anesthesia in ten pigs. Blood pressure measurements and magnetic resonance imaging (MRI) of the kidneys, renal arteries, and surrounding structures were obtained immediately before and after the interventions and after 4 weeks. Histological examinations of periarterial tissues and determination of renal norepinephrine (NE) concentration were performed to assess treatment efficacy. RESULTS AND DISCUSSION: In each pig, 9.8 ± 2.6 sonications with a mean energy deposition of 2,670 ± 486 J were performed. The procedure was well tolerated by all pigs. No major complications occurred. MRgHiFUS induced periarterial edema in three pigs, but only one pig showed corresponding histological changes. The NE level of the treated kidney was lower in five pigs (-8% to -38%) compared to the untreated side. Overall, there was no significant difference between the NE values of both kidneys in any of the treated pigs. Postinterventional MRI indicated absorption of ultrasound energy at the transverse process and fascia. CONCLUSION: MRgHiFUS had some thermal periarterial effects but failed to induce renal denervation. Insufficient energy deposition is most likely attributable to a small acoustic window with beam path impediment in the porcine model. Since HiFUS treatment in humans is expected to be easier to perform due to better access to renal sympathetic nerves, further studies of this method are desirable to investigate the potential of MRgHiFUS as an alternative for patients not suitable for catheter-based renal sympathicolysis.

Intra-arterial ultra low iodine CT angiography of renal transplant arteries.

PURPOSE: This study was designed to evaluate the technical feasibility and the image quality of intra-arterial 320-row CT angiography (ia-CTA) in the detection of transplant renal artery stenosis (TRAS) using a very low dose of contrast agent. METHODS: Evaluation of ia-CTA using a 4F catheter in ten patients with impaired renal transplant function and suspected TRAS. Average amount of contrast agent applied was 10 ± 3.7 ml standard deviation (SD). Patient serum creatinine levels had been monitored for 72 h. TRAS was detected and graded (1: less than 20 %; 2: 20-49 %; 3: 50-74 %; 4: 75-99 %; 5: total occlusion) and presence of kinking was recorded. Attenuation and vessel delineation were parameters for image quality analysis of the renal arterial supply, divided into four segments. Subjective image quality. RESULTS: Ia-CTA of the renal transplant was technically successful in all patients, revealing relevant stenoses in 7 of 10 patients. Serum creatinine levels before and after ia-CTA were 2.71 ± 1.46 and 2.56 ± 1.39 mg/dl, respectively. None of the patients developed signs of contrast-induced nephropathy within 72 h. Subjective image quality was excellent in all four segments, rated by two separate readers. No segment was found to be nondiagnostic. Mean attenuation values in the arterial segments ranged between 754 and 987 Hounsfield units. CONCLUSIONS: Wide detector ia-CTA for the diagnosis of TRAS is feasible using very low doses of contrast agent and results in high image quality.

Simultaneous dual-isotope SPECT/CT with (99m)Tc- and (111)In-labelled albumin microspheres in treatment planning for SIRT.

OBJECTIVES: To investigate simultaneous dual-isotope SPECT/CT with two differently radioisotope-labelled albumin-microsphere fractions for treatment planning of hepatic radioembolisation. METHODS: In addition to (99m)Technetium-labelled albumin microspheres (commercially available), we performed labelling with (111)Indium. Binding stability of (111)Indium-labelled microspheres was tested in vitro and in vivo in mice. Simultaneous dual-isotope SPECT/CT imaging was validated in an anthropomorphic torso phantom; subsequently, dual-isotope SPECT/CT was performed under in-vivo conditions in pigs (n = 3) that underwent transarterial injection of (99m)Technetium- and (111)Indium-labelled microspheres in the liver (right and left hepatic artery, respectively), in both kidneys and in the gluteal musculature. In total, n = 18 transarterial injections were performed. RESULTS: In-vitro testing and in-vivo studies in mice documented high binding stability for both (99m)Technetium-labelled and (111)Indium-labelled microsphere fractions. In phantom studies, simultaneous dual-isotope SPECT/CT enabled reliable separation of both isotopes. In pigs, the identified deposition of both isotopes could be accurately matched with intended injection targets (100 %, 18/18 intended injection sites). Furthermore, an incidental deposition of (99m)Technetium-labelled microspheres in the stomach could be correlated to the test injection into a right hepatic artery. CONCLUSION: Simultaneous dual-isotope SPECT/CT after transarterial injection with (99m)Technetium- and (111)Indium-labelled microspheres is feasible. Thus, it may offer additional, valuable information compared to single (99m)Technetium-labelled albumin examinations. KEY POINTS: • Simultaneous dual-isotope SPECT/CT with (111) In- and (99m) Tc-labelled albumin microspheres is feasible. • Differentiation of two microsphere fractions after transarterial injection is possible. • The origin of an extra-hepatic microsphere deposition can be correlated to the corresponding artery. • This technique could reduce the setup time for selective internal radiation treatment.

Identification of the iodine concentration that yields the highest intravascular enhancement in MDCT angiography.

OBJECTIVE: The objective of our study was to identify the iodine concentration that yields the highest intravascular contrast enhancement in MDCT angiography by intraindividual comparison in an animal model. MATERIALS AND METHODS: Six pigs underwent repeated chest MDCT examinations under standardized conditions using the same contrast medium (iopromide) with different iodine concentrations (150, 240, 300, and 370 mg I/mL). The contrast injection protocol was adapted to ensure an identical iodine delivery rate of 1.5 g I/s and the same total iodine dose of 300 mg/kg of body weight for all studies. Dynamic CT scans were acquired at the levels of the pulmonary artery and the ascending and descending aorta. Pulmonary and aortic peak enhancement values as well as time to peak (TTP) were calculated from time-enhancement curves. RESULTS: Pulmonary and aortic peak contrast enhancement values were significantly higher with the 240 and 300 mg I/mL contrast media than the 150 and 370 mg I/mL contrast media (e.g., ascending aorta: 240 vs 150, p = 0.0070; 300 vs 150, p = 0.0096; 240 vs 370, p = 0.0262; 300 vs 370, p = 0.0079). TTP values tended to be lower for the 150 mg I/mL contrast medium than for the contrast media with higher iodine concentrations. CONCLUSION: Comparison of contrast media with iodine concentrations ranging from 150 to 370 mg I/mL showed that contrast enhancement was significantly improved with the use of 240 and 300 mg I/mL contrast media given a fixed identical iodine delivery and normalized total iodine load in a porcine model. Contrast media with a moderate iodine concentration are most suitable for obtaining the highest intravascular contrast enhancement in CT angiography.

Contrast-enhanced MRI predicts local recurrence of osteoid osteoma after radiofrequency ablation.

INTRODUCTION: Osteoid osteoma is a painful benign tumour, which is commonly treated by radiofrequency ablation (RFA). The goal of this study is to assess the value of contrast-enhanced magnetic resonance imaging (MRI) for predicting clinical success after RFA of osteoid osteoma. METHODS: Twenty consecutive patients (14 male, 6 female; mean age 23.3 ± 13.4 years) suffering from osteoid osteoma underwent unenhanced and contrast-enhanced T1-weighted MRI the day after RFA. Post-interventional contrast enhancement of the nidus was analyzed by comparing signal-to-noise ratios (SNR) of the nidus before and after contrast administration. The SNR between pre- and post-contrast scans was computed. RESULTS: There were no significant differences in SNR between pre- and post-contrast scans in the area of ablation (P = 0.1583), while the SNR exceeded one in four patients, indicating residual contrast enhancement. In three of these patients clinical symptoms recurred, requiring re-ablation, while one patient remained free from symptoms during follow-up. In patients with a pre- and post-contrast SNR of ≤ 1.18 no local recurrence was observed. CONCLUSIONS: Contrast enhancement on T1-weighted MRI imaging seems to be predictive of clinically unsuccessful RFA in osteoid osteoma. Patients with a SNR increase of ≥ 20% after contrast administration might be considered for re-ablation to avoid symptomatic tumour recurrence.

High pressure versus standard port system: comparison of implantation and complications.

INTRODUCTION: Completely implantable access ports for high pressure contrast media injection have been in use in clinical routine for a relatively short time. The purpose of our study was to compare a high pressure port system with a standard port system with regard to implantation and complications. METHODS: In 94 oncological patients a completely implantable access port was implanted. Patients (n = 49) planned for oncological follow-up computed tomography (CT) received a high pressure port system. Other patients (n = 45) received a standard port system. Intrainterventional pain perception, postinterventional catheter tip migration and complications were analyzed. RESULTS: No major periinterventional complications occurred. Intrainterventional pain perception was not significantly different between the two groups. A significantly lower rate of tip migration was observed in the high pressure port group (P = 0.03) and when the port system was implanted on the right side (P = 0.03). In the standard port group catheter occlusion occurred in three patients (7%) and a catheter loop in one patient (2%) whereas no such complications occurred within the high pressure port group. Venous thrombosis was detected in one patient (2%) with a high pressure port; this did not occur in the standard port group. CONCLUSIONS: Implantation and use of a high pressure port device is safe and reliable: the complications are comparable to those of a standard port device. High pressure port systems should be considered for implantation, especially in patients who will require frequent CTs.

Bile aspiration and hydrodissection to prevent complications in hepatic RFA close to the gallbladder.

BACKGROUND: Radiofrequency ablation (RFA) of liver tumors is a mainstay of interventional oncology. Its application, however, is limited by tumor size and location with lesions located within 1 cm to the gallbladder being at increased risk for complications. PURPOSE: To evaluate the safety of hepatic RFA after bile aspiration with or without additional hydrodissection for lesions adjacent to the gallbladder. MATERIAL AND METHODS: Six patients undergoing RFA of tumors with a distance of less than 1 cm to the gallbladder were retrospectively identified from a computer database. All patients underwent RFA combined with percutaneous bile aspiration from the gallbladder. In four patients additional hydrodissection was performed. Technical success and post-interventional complications were assessed by reviewing images and patient charts. RESULTS: Ablations were successfully completed in 5/6 patients. In one patient with incomplete ablation re-ablation was performed 2 months after the initial procedure. Minor complications occurred in three patients, including right-sided pleural effusion, hematoma in the gallbladder fossa, and intralesional hemorrhage in one patient each. There were no cases with cholecystitis or damage to the gallbladder during follow-up. CONCLUSION: Bile aspiration with or without additional hydrodissection permits safe RFA of tumors located close to the gallbladder.

Generic integration of content-based image retrieval in computer-aided diagnosis.

Content-based image retrieval (CBIR) offers approved benefits for computer-aided diagnosis (CAD), but is still not well established in radiological routine yet. An essential factor is the integration gap between CBIR systems and clinical information systems. The international initiative Integrating the Healthcare Enterprise (IHE) aims at improving interoperability of medical computer systems. We took into account deficiencies in IHE compliance of current picture archiving and communication systems (PACS), and developed an intermediate integration scheme based on the IHE post-processing workflow integration profile (PWF) adapted to CBIR in CAD. The Image Retrieval in Medical Applications (IRMA) framework was used to apply our integration scheme exemplarily, resulting in the application called IRMAcon. The novel IRMAcon scheme provides a generic, convenient and reliable integration of CBIR systems into clinical systems and workflows. Based on the IHE PWF and designed to grow at a pace with the IHE compliance of the particular PACS, it provides sustainability and fosters CBIR in CAD.

Functional MR imaging of the eustachian tube in patients with clinically proven dysfunction: correlation with lesions detected on MR images.

OBJECTIVES: To visualise the function of the Eustachian tube by MRI and assess the effect of surrounding lesions. METHODS: Using 1.5 T MRI, 32 Eustachian tubes of 16 patients with clinically proven dysfunction (clinical symptoms, such as autophonia and fullness and non-opening at tympanometry) were investigated. For depiction of the anatomy and associated abnormalities, coronal and axial T2-weighted turbo spin echo sequences and a T1-weighted-2D-gradient echo sequences were acquired. Eustachian tube opening was analysed with real time turbo-gradient echo sequences during a Valsalva manoeuvre. RESULTS: Dysfunction, that is, failure of opening of the Eustachian tube as shown by MRI, correlated in all patients with tympanometry. Lesions detected included nasopharyngeal carcinoma in 4 patients. Mucosal swelling in the paranasal sinus was present in 9 patients. One patient had postoperative defects. In two patients both pharyngotympanic tubes did not open although no structural abnormalities could be depicted. CONCLUSIONS: The opening of the Eustachian tubes during the Valsalva manoeuvre is assessable on MRI. Failure of opening may be due to swelling of the mucosa and may be also associated with tumours. MRI assessment may be helpful in patients with chronic otitis media, where the information about tubal function is important in preoperative planning. KEY POINTS: •Eustachian tube opening during Valsalva manoeuvre can be visualised with MRI •Lesions hampering tubal opening can be delineated at the same MRI examination •Functional MRI of the Eustachian tubes might determine the cause of dysfunction.

Web-based bone age assessment by content-based image retrieval for case-based reasoning.

PURPOSE: Maturity estimation by radiological bone age assessment (BAA) is a frequent task for pediatric radiologists. Following Greulich and Pyle, all hand bones are compared with a standard atlas, or a subset of bones is examined according to Tanner and Whitehouse. We support BAA comparing the epiphyses of a current case to similar cases with validated bone age by content-based image retrieval (CBIR). METHODS: A web-based prototype case-based retrieval system for BAA was developed and is publicly available. Hand radiographs from the USC database or user uploads may be retrieved by image-based query. The ten best matching cases for each epiphysis are retrieved by CBIR and displayed with their BAA, similarity score, and the derived age estimate. The similarity is approximated by cross-correlation. The USC hand database includes 1,101 cases comprising four ethnic groups of both genders between zero and 18 years of chronological age with radiographs and two annotated BAA. The USC image data have been enriched by marking the epiphyseal centers between metacarpals and distal phalanges. RESULTS: Leave-one-out experiments yielded a mean error rate of 0.99 years and a standard deviation of 0.76 years in comparison with the mean USC-BAA. The research prototype enables radiologists to judge their agreement based on similarity of retrieved cases and the derived age. CONCLUSIONS: CBIR provides support to the radiologist with a second opinion for BAA. Self-explanatory web applications can be established to support workflow integration. Enhancements in similarity computation and interface usability may further improve the system.