Comparison of contrast-enhanced videofluoroscopy to unenhanced dynamic MRI in minor patients following surgical correction of velopharyngeal dysfunction

OBJECTIVES

To compare dynamic magnetic resonance imaging (MRI) with videofluoroscopy (VFS) regarding image quality and assessment of gap size between soft palate (SP) and posterior pharyngeal wall (PPW) in children and adolescents following surgical correction of velopharyngeal dysfunction (VPD).

METHODS

Twenty-one patients undergoing unenhanced 3-T MRI and contrast-enhanced VFS were included in this IRB-approved prospective study. The MRI scan protocol comprised refocused gradient-echo sequences in transverse and sagittal planes during speech, with TE 1.97 ms, TR 3.95 ms, flip angle 8°, matrix size 128 × 128, and 5-mm slice thickness. Radial k-space sampling and sliding window reconstruction were used to achieve an image acquisition rate of 28 frames per second (fps). VFS with 30 fps was similarly performed in both planes. Closure of the velopharyngeal port during phonation was evaluated by two experienced radiologists.

RESULTS

Eleven (52.4%) patients displayed a complete closure, whereas ten (47.6%) patients showed a post-operative gap during speech. VFS and MRI equally identified the cases with persistent or recurrent VPD. Differences in SP-PPW distance between VFS (3.9 ± 1.6 mm) and MRI (4.1 ± 1.5 mm) were not statistically significant (p = 0.5). The subjective overall image quality of MRI was rated inferior (p < 0.001) compared with VFS, with almost perfect inter-rater agreement (κ = 0.90). The presence of susceptibility artifacts did not limit anatomical measurements.

CONCLUSION

Dynamic MRI is equally reliable as VFS to assess persistent or recurrent inadequate velum closure in patients following surgical treatment of VPD.

KEY POINTS

• Unenhanced 3-T dynamic MRI and contrast-enhanced videofluoroscopy are equally useful for the identification of patients with incomplete velopharyngeal closure during speech. • MRI using refocused gradient-echo acquisition with radial k-space sampling and sliding window reconstruction generates diagnostic images with 28 frames per second. • MRI can offer a radiation-free alternative to currently established videofluoroscopy for young patients.

High-pitch Dual-source CT Angiography before TAVI - the Value of ECG Gating

PURPOSE

To investigate image quality, and radiation dose between ECG-gated singlesource and dual-source CT Angiography (CTA) protocols for planning of Trans-catheter Aortic Valve Implantation (TAVI) with a reference non ECG-gated single-source protocol.

METHODS

A total of 120 patients were included in four groups: Non ECG-gated single-source (SS), ECG-gated single-source (SSECG), ECG-gated dual-source high-pitch (DSECG), or non-ECG-gated dual-source high-pitch mode (DS). Qualitative image quality of the aortic annulus, aortic valve, and coronary ostia as well as presence of motion or stair-step artefacts of the thoracic aorta were independently assessed by two readers. Quantitative image quality was assessed to calculate contrast to noise ratio.

RESULTS

Subjective and objective scoring of motion artefacts was significantly reduced in SSECG, DSECG and DS (p= 0.010). The imaging length was comparable between groups. Aortic annulus, aortic valve, and coronary ostia were reliably evaluable in all patients with SSECG, DSECG and DS protocols.

CONCLUSION

High-pitch, dual-source CT angiography of the whole aorta with or without ECG gating is a dose-efficient and time-saving examination strategy before TAVI. However acquisition timing within the cardiac cycle needs to be taken into account.

CT-guided percutaneous biopsy of suspect pancreatic lesions: radiological and clinical outcome

AIM

To evaluate the clinical utility of computed tomography (CT)-guided percutaneous biopsies of suspect pancreatic lesions regarding safety, efficiency, radiation dose, intervention time, diagnostic yield, and complications.

MATERIALS AND METHODS

Between 2015 and 2018, 48 patients (18 female, 30 male; mean age: 64.2 years) with suspect pancreatic lesions underwent CT-guided percutaneous biopsy. Ultrasound-guided biopsy of all lesions was not possible or without any result. CT-guided interventions were compared according to the following intervention parameters: radiation dose, procedure duration, number of needle correction scans. Evaluation criteria included technical success as well as major and minor complications according to the Society of Interventional Radiology.

RESULTS

Biopsies were performed successfully in 100% of patients. No major side effects occurred during intervention. As a minor complication, 29.2% showed focal haemorrhage. Seventy-seven percent of lesions had a malignant appearance, and benign inflammatory lesions were found in 23%. The mean size of the target lesions was 2.9 cm (range: 0.7-2.3 cm). The mean target access path within the patient was 8 cm (range: 3-14 cm). The duration to completion was 12 minutes (range: 3 minutes 30 seconds to 30 minutes). The dose-length product of the intervention was 89.5 mGy·cm (range: 11-350 mGy·cm). The average number needle correction scans was 31.1 (range: 6-36).

CONCLUSION

CT-guided biopsy of suspect pancreatic lesions is an efficient and safe method. It can be performed within short intervention times and low radiation exposure for differentiation of unclear lesions.

HCC: Transarterial Therapies-What the Interventional Radiologist Can Offer

With the increasing incidence of hepatocellular carcinoma (HCC) and its high mortality rates, effective treatment options are of urgent need, preferably in a multidisciplinary setting. In the management of those patients, interventional radiologists play a key role. In this article, we reviewed the current literature for regional, intraarterial treatment strategies of advanced-stage HCC including conventional transarterial chemoembolization, transarterial embolization, transarterial embolization with drug-eluting beads, and selective internal radiation therapy.

Gadolinium-enhanced imaging of pediatric thoracic lymphoma: is intravenous contrast really necessary?

OBJECTIVES

Increasing awareness of potential side effects from gadolinium-based contrast agents has underlined the need for contrast-free magnetic resonance imaging (MRI). Numerous recent articles evaluated the risk of potential brain deposits, with the result that research is putting the focus more on alternative unenhanced imaging techniques. The aim of this study was to determine the need for contrast media for chest MRI in primary staging and follow-up care of lymphoma.

METHODS

This monocentric, retrospective study encompassed patients under 25 years of age who had undergone histopathological examination of thoracic lymph nodes and at least one chest MRI examination with unenhanced and contrast-enhanced sequences. Seven different thoracic lymph node stations including mediastinal, hilar, periclavicular, and axillary regions were evaluated by two readers regarding lesion diameter, number, shape, necrosis, and infiltration of surrounding structures. Findings were categorized into suspicious (> 1 cm; round; necrosis; infiltration) or non-suspicious.

RESULTS

Fifty-one patients (mean age, 16.0 ± 3.7 yrs) with thoracic Hodgkin (70.6%) and non-Hodgkin lymphoma (25.5%) and lymphadenopathy (3.9%) were retrospectively included. Most lymph nodes categorized as suspicious were located in the mediastinal station (86.4%). High agreement (κ = 0.81) between unenhanced and contrast-enhanced sequences was found for both suspicious and non-suspicious lymph nodes. Significant (p < 0.001), but small difference (1 mm) was observed only in sizing mediastinal lymph nodes (all other p > 0.05). No significant difference (smallest p = 0.08) was shown for the use of five different types of contrast media.

CONCLUSION

MRI in young patients with thoracic lymphoma can safely be done without the use of contrast agent.

KEY POINT

• Thoracic magnetic resonance imaging in young lymphoma patients can safely be done without gadolinium-based contrast agents.

Virtual Noncalcium Dual-Energy CT: Detection of Lumbar Disk Herniation in Comparison with Standard Gray-scale CT

Purpose To assess the diagnostic performance of dual-energy CT with reconstruction of virtual noncalcium (VNCa) images for the detection of lumbar disk herniation compared with standard CT image reconstruction. Materials and Methods For this retrospective study, 41 patients (243 intervertebral disks; overall mean age, 68 years; 24 women [mean age, 68 years] and 17 men [mean age, 68 years]) underwent clinically indicated third-generation, dual-source, dual-energy CT and 3.0-T MRI within 2 weeks between March 2017 and January 2018. Six radiologists, blinded to clinical and MRI information, independently evaluated conventional gray-scale dual-energy CT series for the presence and degree of lumbar disk herniation and spinal nerve root impingement. After 8 weeks, readers reevaluated examinations by using color-coded VNCa reconstructions. MRI evaluated by two separate experienced readers, blinded to clinical and dual-energy CT information, served as the standard of reference. Sensitivity and specificity were the primary metrics of diagnostic performance. Results A total of 112 herniated lumbar disks were depicted at MRI. VNCa showed higher overall sensitivity (612 of 672 [91%] vs 534 of 672 [80%]) and specificity (723 of 786 [92%] vs 665 of 786 [85%]) for detecting lumbar disk herniation compared with standard CT (all comparisons, P < .001). Interreader agreement was excellent for VNCa and substantial for standard CT (κ = 0.82 vs 0.67; P < .001). VNCa achieved superior diagnostic confidence, image quality, and noise scores compared with standard CT (all comparisons, P < .001). Conclusion Color-coded dual-energy CT virtual noncalcium reconstructions show substantially higher diagnostic performance and confidence for depicting lumbar disk herniation compared with standard CT. © RSNA, 2018.

CT-guided nephrostomy-An expedient tool for complex clinical scenarios

INTRODUCTION & OBJECTIVES

Percutaneous nephrostomy [1] has emerged as a pivotal approach in the therapeutic management of the obstructed urinary tract. A consecutive incorporation of ultrasonic and radiographic guidance, the approach experienced an almost ubiquitious distribution while most centers currently applying either one or both of these tools jointly. However, success of ultrasound-guidance is limited in obese patients and non-dilated uropathy. In turn, fluoroscopy usually requires an opacification of the urinary collecting system by intravenous or antegrade contrast media injection, which might be harmful for already impaired renal function, raise intrapelvic pressure and augment the risk of sepsis and hemorrhage. CT-guided PCN aids in overcoming these limitations. In the current study, we present the experience of a tertiary referral center with this technique.

MATERIALS & METHODS

Epidemiological and clinical data of all patients treated with a CT-guided PCN of native kidneys at the University Hospital Frankfurt between October 2003 and October 2013 were retrospectively collected from the patient charts. Procedural parameters including radiological aspects, technical and therapeutic success, complication and mortality rate have been analyzed statistically.

RESULTS

In total, 140 PCN procedures have been performed in 77 patients with a median age of 69 (± 13). The median body mass index was 27 with 66.6% of patients being overweight or obese. Charlson comorbidity index was 7 ranging 0-16. Indications for PCNs were obstructive uropathy (62.9), urine extravasation (22.9%), urinary tract fistulas (11.4%) and technical reasons (2.8%). In 68.8% of patients, initial diagnosis was malignancy. 56.4% of kidneys were non-dilated before puncture. In 78.4% prone position, otherwise supine oblique position (17.3%) or supine position (4.3%) was used. 71.4% of PCNs were carried out solely under local anesthesia. Technical success has been achieved in 90% with a complication rate of 3.6% (all grade minor B) and was not significantly different between dilated and non-dilated kidneys. 42.9% of fistulas and 64.3% of urinary tract leakages, healed after PCN placement. 30 days mortality rate was 5.2% without being directly associated with the PCN procedure itself.

CONCLUSION

CT-guided PCN is a feasible approach associated with low morbidity. It is particularly useful in complex clinical scenarios e.g. critically ill, newly operated or obese patients as well as non-dilated kidneys. Moreover, it represents a minimally-invasive option for treating leakages and fistulas of the urinary tract.

The portal vein as a distinct immunological compartment - A comprehensive immune phenotyping study

Advanced liver diseases are associated with impaired intestinal barrier function, which results in bacterial influx via the portal vein to the liver, causing hepatic and systemic inflammation. Little is known about possible concomitant trafficking of immune cells from the intestines to the liver. We therefore performed a comprehensive immunophenotyping study of the portal venous versus peripheral blood compartment in patients with liver cirrhosis who received a transjugular intrahepatic portosystemic stent shunt (TIPS). Our analysis suggests that the portal vein constitutes a distinct immunological compartment resembling that of the intestines, at least in patients with advanced liver cirrhosis. In detail, significantly lower frequencies of naïve CD4⁺ T cells, monocytes, dendritic cells and Vδ2 T cells were observed in the portal vein, whereas frequencies of activated CD4⁺ and CD8⁺ T cells, as well as of mucosa-associated Vδ1 T cells were significantly higher in portal venous compared to peripheral blood. In conclusion, our data raises interesting questions, e.g. whether liver cirrhosis-associated chronic inflammation of the intestines and portal hypertension promote an influx of activated intestinal immune cells like γδ T cells into the liver.

Transarterial Chemoembolization (TACE) Using Mitomycin with or without Irinotecan for Hepatocellular Carcinoma in European Patients

BACKGROUND

We evaluated survival data and local tumor control in 2 groups of patients with hepatocellular carcinoma (HCC) treated with different chemotherapeutic agents for transarterial chemoembolization (TACE).

METHODS

28 patients (median age 63 years) with HCC were repeatedly treated with chemoembolization at 4-week intervals. 20 patients had Barcelona Clinic Liver Cancer (BCLC) stage B, while 8 patients obtained chemoembolization for bridging purposes (BCLC stage A). In total, 98 chemoembolizations were performed (median 3.0 treatments/patient). The administered chemotherapeutic agent comprised either mitomycin only (n = 14; 50%) or mitomycin in combination with irinotecan (n = 14; 50%). Lipiodol plus degradable starch microspheres was used for all embolizations. Local tumor response was assessed by magnetic resonance imaging using modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria. Progression-free survival (PFS) was evaluated.

RESULTS

In the mitomycin-irinotecan group, complete response (CR) was observed in 21.4%, partial response (PR) in 42.9%, stable disease (SD) in 28.6%, and progressive disease (PD) in 7.1%. In the mitomycin group, PR was observed in 57.2% of patients, SD in 21.4%, and PD in 21.4% (p = 0.043). The PFS of patients after chemoembolization with mitomycin was 4 months compared to the significantly longer PFS of 12 months in the mitomycin-irinotecan group (p = 0.003).

CONCLUSION

Chemoembolization of HCC with mitomycin and irinotecan is the preferred treatment option for achieving local control and better PFS.

90-kVp low-tube-voltage CT pulmonary angiography in combination with advanced modeled iterative reconstruction algorithm: effects on radiation dose, image quality and diagnostic accuracy for the detection of pulmonary embolism

OBJECTIVE

To evaluate low-tube-voltage 90-kVp CT pulmonary angiography (CTPA) with advanced modeled iterative reconstruction algorithm (Admire) compared to 120-kVp equivalent dual-energy (DE) acquisition with regards to radiation exposure, image quality and diagnostic accuracy for pulmonary embolism (PE) assessment.

METHODS

CTPA studies of 40 patients with suspected PE (56.7 ± 16.3 years) performed on a third-generation 192-slice dual-source CT scanner were retrospectively included. 120-kVp equivalent linearly-blended (60% 90-kVp, 40% 150-kVp) and 90-kVp images were reconstructed. Attenuation and noise of the pulmonary trunk were measured to calculate contrast-to-noise ratios (CNR). Three radiologists assessed the presence of central and segmental PE and diagnostic confidence. Interobserver agreement was calculated using intraclass correlation coefficient (ICC). Radiation exposure was assessed as effective dose (ED).

RESULTS

Pulmonary trunk CNR values were significantly increased in 90-kVp compared to linearly-blended series (15.4 ± 6.3 vs 11.3 ± 4.6, p < 0.001). Diagnostic accuracy for PE assessment was similar in both series with excellent interobserver agreement (p = 0.48; ICC, 0.83; p = 0.48). Overall confidence for PE assessment was rated excellent for both series with a significant advantage for linearly-blended series (p < 0.001; 4.1 vs 3.8). ED was reduced by 37.2% with 90-kVp compared to 120-kVp equivalent image series (1.1 ± 0.6 vs 1.7 ± 0.7 mSv, p < 0.001).

CONCLUSION

90-kVp CTPA with Admire provided increased quantitative image quality with similar diagnostic accuracy and confidence for PE assessment compared to 120-kVp equivalent acquisition, while radiation dose was reduced by 37.2%. Advances in knowledge: 90-kVp CTPA with an advanced iterative reconstruction algorithm results in excellent image quality and reduction of radiation exposure without limiting diagnostic performance.

Survival of patients with non-resectable, chemotherapy-resistant colorectal cancer liver metastases undergoing conventional lipiodol-based transarterial chemoembolization (cTACE) palliatively versus neoadjuvantly prior to percutaneous thermal ablation

PURPOSE

To determine overall (OS) and progression-free survival (PFS) for cTACE alone and in combination with percutaneous thermal ablation in patients with non-resectable, chemotherapy-resistant colorectal cancer liver metastases (CRLM).

MATERIAL AND METHODS

The study included 452 patients undergoing 2654 repetitive cTACE treatments of CRLM. 233 patients were treated palliatively using only cTACE, whereas 219 patients were treated with cTACE in a neoadjuvant intend with subsequent thermal ablation (either microwave ablation or laser-induced thermotherapy). The chemotherapeutics agents used, in either single-, double-, or triple-combinations, included MitomycinC, Gemcitabine, Irinotecan, and Cisplatin. Several factors were analysed to determine their prognostic value in terms of OS and PFS.

RESULTS

Palliative use of cTACE resulted in a median OS and PFS of 12.6 and 5.9 months, whereas the neoadjuvant use of cTACE showed a median OS and PFS of 25.8 and 10.8 months. The differences in OS and PFS between the two groups were statistically significant (p < 0.001). Extrahepatic metastases were a significant prognostic factor in the OS and PFS analysis of the palliative and neoadjuvant group. In addition, number, location, and mean size of metastases were significant prognostic factors for OS and PFS in the neoadjuvant group. Sex, primary tumor location, T- and N-parameters of the TNM staging system, time of liver metastases appearance, ablation method, and patient age did not significantly impact OS and PFS in either patient group. The most distinct response to cTACE was observed in metastases that were treated with a triple-combination of chemotherapeutics (p = 0.021).

CONCLUSION

cTACE is an effective treatment option in advanced non-resectable CRLM. Chemoembolization followed by ablation further increases survival rates. A triple combination of chemotherapeutics improves response to cTACE.

Transarterial chemoembolization (TACE) using mitomycin and lipiodol with or without degradable starch microspheres for hepatocellular carcinoma: comparative study

Background

To evaluate survival data and local tumor control after transarterial chemoembolization in two groups with different embolization protocols for the treatment of HCC patients.

Methods

Ninty-nine patients (mean age: 63.6 years), 78 male (78.8%) with HCC were repeatedly treated with chemoembolization in 4-week-intervals. Eighty-eight patients had BCLC-Stage-B and in 11 patients, chemoembolization was performed for bridging (BCLC-Stage-A). In total, 667 chemoembolization treatments were performed (mean 6.7 treatments/patient). The administered chemotherapeutic agent included mitomycin. For embolization, lipiodol only (n = 51;51.5%; mean age 63.8 years; 38 male), or lipiodol plus degradable starch microspheres (DSM) (n = 48; 48.5%; mean age 63.4 years; 40 male) were used. The local tumor response was assessed by MRI using Response Evaluation Criteria in Solid Tumors 1.1 (RECIST 1.1). Patient survival times were evaluated using Kaplan-Meier curves and log-rank tests.

Results

The local tumor control in the lipiodol-group was: PR (partial response) in 11 (21.6%), SD (stable disease) in 32 (62.7%) and PD (progressive disease) in 8 cases (15.7%). In the lipiodol-DSM-group, PR was seen in 14 (29.2%), SD in 22 (45.8%), and PD in 12 (25.0%) individuals (p = 0.211). The median survival of patients after chemoembolization with lipiodol was 25 months and in the lipiodol-DSM-group 28 months (p = 0.845).

Conclusion

Our data suggest a slight benefit of the use of lipiodol and DSM in comparison of using lipiodol only for chemoembolization of HCC in terms of local tumor control and survival data, this trend did not reach the level of significance.

Microwave ablation of pancreatic tumors

OBJECTIVES

To evaluate the clinical performance of percutaneous microwave ablation (MWA) for treatment of locally-advanced-pancreatic-cancer (LAPC).

MATERIAL AND METHODS

Twenty-two MWA sessions (August 2015-March 2017) in 20 patients with primary pancreatic cancer (13 men, 7 women, mean-age: 59.9 ± 8.6 years, range: 46-73 years), who had given informed consent, were retrospectively evaluated. All procedures were performed percutaneously under CT-guidance using the same high-frequency (2.45-GHz) MWA device. Tumor location and diameter, ablation diameter and volume, roundness, duration, technical success and efficacy, output energy, complications, and local tumor progression defined as a tumor focus connected to the edge of a previously technically efficient ablation zone were collected.

RESULTS

Seventeen pancreatic malignant tumors (77.3%) were located in the pancreatic head and five (22.7%) in the pancreatic tail. Initial Mean Tumor Diameter was 30 ± 6 mm. Technical success and efficacy were idem (100%). No major complications occurred. Two patients (9.1%) showed minor complications of severe local pain related to MWA. Post-ablation diameter was on average 34.4 ± 5.8 mm. Mean ablation volume was 7.8 ± 3.8 cm³. The mean transverse roundness index was 0.74 ± 0.14. Mean ablation time was 2.6 ± 0.96 min. The mean applied energy per treatment was 9627 ± 3953 J. Local tumor progression was documented in one case (10%) of the 10/22 available three-month follow-up imaging studies.

CONCLUSION

High-frequency (2.45 GHz) microwave ablation (MWA) for treatment of unresectable and non-metastatic locally-advanced-pancreatic-cancer (LAPC) shows promising results regarding feasibility and safety of percutaneous approach after short-term follow-up and should be further evaluated.

Trans-arterial chemoperfusion for the treatment of liver metastases of breast cancer and colorectal cancer: Clinical results in palliative care patients

AIM

To evaluate the clinical value and efficiency of trans-arterial chemoperfusion (TACP) in patients with liver metastases from breast cancer (BC) and colorectal cancer (CRC).

METHODS

We treated 36 patients with liver metastases of BC (n = 19, 19 females) and CRC (n = 17; 8 females, 9 males) with repeated TACP. The treatment interval was 4 wk. TACP was performed with gemcitabine (1000 mg/m²) and mitomycin (10 mg/m²), administered within 1 h after positioning the catheter tip in the hepatic artery. Before treatment, the size, location, tumour volume, vascularization and number of liver tumours were evaluated using magnetic resonance imaging (MRI). Tumour response was evaluated according to the Response Evaluation Criteria in Solid Tumors guidelines.

RESULTS

TACP using gemcitabine and mitomycin for metastases from CRC and BC was performed without any serious side effects. The follow-up MRI showed a therapeutic response in 84.2% of the BC patients - stable disease 47.4% and partial response 36.8%. A progression was seen in 15.8%. CRC patients showed a therapeutic response in 52.9% of cases. A progression of the disease was documented in 47.1% of the patients with CRC. These data show that TACP in patients with liver metastases of BC leads to a significantly better therapeutic response compared with CRC patients (P = 0.042). The median survival time was 13.2 mo for the BC patients, which is significantly longer than for CRC patients at 9.3 mo (P = 0.001).

CONCLUSION

TACP for liver metastases of BC appears to be a safe and effective palliative treatment with improved outcomes in comparison to patients with CRC.

Thermal Ablation of Lung Tumors: Focus on Microwave Ablation

Background Image-guided thermal ablation can be used for the treatment of medically inoperable primary and metastatic lung cancer. These techniques are based on the heating up or freezing (cryoablation) of a volume of tissue around a percutaneous applicator that induces necrosis of the tumor. Method The English-language literature concerning thermal ablation of the lung was reviewed. Radiofrequency ablation (RFA) is the most widely performed and investigated of these techniques. Microwave ablation (MWA) represents a relatively new alternative that shares the same indications and is conducted in a very similar fashion as RFA. It has been experimentally and clinically shown that MWA produces larger, more spherical ablation zones over shorter periods of time compared to RFA. Seven different MWA systems are available in Europe and the USA with significant differences in the size and shape of the produced ablation zones. Results The types of complications caused by MWA and their rates of occurrence are very similar to those caused by RFA. The local progression rates after MWA of lung malignancies vary between 0 % and 34 % and are similar to those in the RFA literature. Conclusion Despite technical improvements, the current generation of MWA systems has comparable clinical outcomes to those of RFA. Key Points  · MWA is a safe technique that should be considered one of the treatment options for medically inoperable lung tumors. · As thermal ablations of lung tumors are becoming more frequent, radiologists should be acquainted with the post-ablation imaging characteristics. · Although MWA has some theoretical advantages over RFA, the clinical outcomes are similar. Citation Format · Vogl TJ, Nour-Eldin NA, Albrecht MH et al. Thermal Ablation of Lung Tumors: Focus on Microwave Ablation. Fortschr Röntgenstr 2017; 189: 828 - 843.

Assessment of the cochlear nerve to facial nerve size ratio using MR multiplanar reconstruction of the internal auditory canal in patients presenting with acquired long-standing hearing loss

OBJECTIVE

To test using the facial nerve as a reference for assessment of the cochlear nerve size in patients with acquired long-standing sensorineural hearing loss (SNHL) using MRI multiplanar reconstruction.

METHODS

The study was retrospectively performed on 86 patients. Group 1 (study group, n = 53) with bilateral long-standing SNHL. Group 2 (control group, n = 33) without hearing loss. The nerve size was measured by drawing a region of interest around the cross-sectional circumference of the nerve in multiplanar reconstruction images.

RESULTS

No significant correlation was noted between the cochlear nerve and facial nerve size, and the patient's age, gender and weight (p > 0.05). In Group 1, the mean ratio of the cochlear to facial nerve size was 0.99 ± 0.30 (range: 0.52-1.86) and 1.12 ± 0.35 (range: 0.34-2.3) for the right and left sides, respectively. In Group 2, it was 1.18 ± 0.23 (range: 0.78-1.71) and 1.25 ± 0.25 (range: 0.85-1.94) for the right and left sides, respectively. The cochlear nerve size was statistically (p = 0.0004) smaller in Group 1 than in Group 2.

CONCLUSION

The cochlear nerve size and the cochlear to facial nerve size ratio are significantly smaller in patients with acquired long-standing SNHL. Advances in knowledge: The facial nerve can be used as a reference for assessment of the cochlear nerve in patients with acquired long-standing SNHL.

Low-dose CT pulmonary angiography on a 15-year-old CT scanner: a feasibility study

Background

Computed tomography (CT) low-dose (LD) imaging is used to lower radiation exposure, especially in vascular imaging; in current literature, this is mostly on latest generation high-end CT systems.

Purpose

To evaluate the effects of reduced tube current on objective and subjective image quality of a 15-year-old 16-slice CT system for pulmonary angiography (CTPA).

Material and Methods

CTPA scans from 60 prospectively randomized patients (28 men, 32 women) were examined in this study on a 15-year-old 16-slice CT scanner system. Standard CT (SD) settings were 100 kV and 150 mAs, LD settings were 100 kV and 50 mAs. Attenuation of the pulmonary trunk, various anatomic landmarks, and image noise were quantitatively measured; contrast-to-noise ratios (CNR) and signal-to-noise ratios (SNR) were calculated. Three independent blinded radiologists subjectively rated each image series using a 5-point grading scale.

Results

CT dose index (CTDI) in the LD series was 66.46% lower compared to the SD settings (2.49 ± 0.55 mGy versus 7.42 ± 1.17 mGy). Attenuation of the pulmonary trunk showed similar results for both series (SD 409.55 ± 91.04 HU; LD 380.43 HU ± 93.11 HU; P = 0.768). Subjective image analysis showed no significant differences between SD and LD settings regarding the suitability for detection of central and peripheral PE (central SD/LD, 4.88; intra-class correlation coefficients [ICC], 0.894/4.83; ICC, 0.745; peripheral SD/LD, 4.70; ICC, 0.943/4.57; ICC, 0.919; all P > 0.4).

Conclusion

The LD protocol, on a 15-year-old CT scanner system without current high-end hardware or post-processing tools, led to a dose reduction of approximately 67% with similar subjective image quality and delineation of central and peripheral pulmonary arteries.

Computed tomography-guided biopsies in children: accuracy, efficiency and dose usage

Background

Computed-tomography-guided interventions are attractive for tissue sampling of paediatric tumor lesions; however, it comes with exposure to ionizing radiation. The aim of this study was to analyse the radiation dose, accuracy and speed of CT-guided interventions in paediatric patient cohort.

Methods

We retrospectively reviewed CT-guided interventions over a 10 -year period in 65 children. The intervention site consisted of bones in 38, chest (lung) in 15 and abdomen (liver, lymph nodes) in 12 cases. Radiation dose and duration of the procedures were analysed. The statistical analysis was performed using dedicated statistical software (BiAS 8.3.6 software, Epsilon Verlag, North Hasted).

Results

All interventions were performed successfully. Mean target access path to lesion within the patients was 6.0 cm (min 3.5 cm, max 11.2 cm). Time duration to complete intervention was 25:15 min (min 17:03 min, max 43:00 min). The dose-length product (DLP) of intervention scan was 29.5 mGy · cm (min 6 mGy · cm, max 85 mGy · cm) with the lowest dose for biopsies in the region of the chest (p = 0.04).

Conclusions

With justified indications, CT-guided paediatric interventions are safe, effective and can be performed both, with short intervention times and low radiation exposure.