Halved contrast medium dose in lower limb dual-energy computed tomography angiography-a randomized controlled trial.

OBJECTIVES: To compare vascular attenuation (VA) of an experimental half iodine-load dual-layer spectral detector CT (SDCT) lower limb computed tomography angiography (CTA) with control (standard iodine-load conventional 120-kilovolt peak (kVp) CTA). METHODS: Ethical approval and consent were obtained. In this parallel RCT, CTA examinations were randomized into experimental or control. Patients received 0.7 vs 1.4 mL/kg of iohexol 350 mgI/mL in the experimental- vs the control group. Two experimental virtual monoenergetic image (VMI) series at 40 and 50 kiloelectron volts (keV) were reconstructed. PRIMARY OUTCOME: VA. SECONDARY OUTCOMES: image noise (noise), contrast- and signal-to-noise ratio (CNR and SNR), and subjective examination quality (SEQ). RESULTS: A total of 106 vs 109 were randomized and 103 vs 108 were analyzed in the experimental vs, control groups, respectively. VA was higher on experimental 40 keV VMI than on control (p < 0.0001), but lower on 50 keV VMI (p < 0.022). Noise was higher on experimental 40 keV VMI than on control (p = 0.00022), but lower on 50 keV VMI (p = 0.0033). CNR and SNR were higher than the control on experimental 40 keV VMI (both p < 0.0001) and 50 keV (p = 0.0058 and p = 0.0023, respectively). SEQ was better on both VMIs in the experimental group than in the control (both p < 0.0001). CONCLUSIONS: Half iodine-load SDCT lower limb CTA at 40 keV achieved higher VA than the control. CNR, SNR, noise, and SEQ were higher at 40 keV, while 50 keV showed lower noise. CLINICAL RELEVANCE STATEMENT: Spectral detector CT with low-energy virtual monoenergetic imaging performed halved iodine contrast medium (CM) lower limb CT-angiography with sustained objective and subjective quality. This facilitates CM reduction, improvement of low CM-dosage examinations, and examination of patients with more severe kidney impairment. TRIAL REGISTRATION: Retrospectively registered 5 August 2022 at clinicaltrials.gov NCT05488899. KEY POINTS: • Contrast medium dosage may be halved in lower limb dual-energy CT angiography with virtual monoenergetic images at 40 keV, which may reduce contrast medium consumption in the face of a global shortage. • Experimental half-iodine-load dual-energy CT angiography at 40 keV showed higher vascular attenuation, contrast-to-noise ratio, signal-to-noise ratio, and subjective examination quality than standard iodine-load conventional. • Half-iodine dual-energy CT angiography protocols may allow us to reduce the risk of PC-AKI, examine patients with more severe kidney impairment, and provide higher quality examinations or salvage poor examinations when impaired kidney function limits the CM dose.

Assessment of preoperative axillary nodal disease burden: breast MRI in locally advanced breast cancer before, during and after neoadjuvant endocrine therapy.

BACKGROUND: Axillary lymph node (LN) metastasis is one of the most important predictors of recurrence and survival in breast cancer, and accurate assessment of LN involvement is crucial. Determining extent of residual disease is key for surgical planning after neoadjuvant therapy. The aim of the study was to evaluate the diagnostic reliability of MRI for nodal disease in locally advanced breast cancer patients treated with neoadjuvant endocrine therapy (NET). METHODS: Thirty-three clinically node-positive locally advanced breast cancer patients who underwent NET and surgery were prospectively enrolled. Two radiologists reviewed the axillary nodes at 3 separate time points MRI examinations at baseline (before the first treatment regimen), interim (following at least 2 months after the first cycle and prior to crossing-over), and preoperative (after the final administration of therapy and immediately before surgery). According to LN status after surgery, imaging features and diagnostic performance were analyzed. RESULTS: All 33 patients had a target LN reduction, the greatest treatment benefit from week 8 to week 16. There was a positive correlation between the maximal diameter of the most suspicious LN measured by MRI and pathology during and after NET, being highest at therapy completion (r = 0.6, P ≤ .001). Mean and median differences of maximal diameter of the most suspicious LN were higher with MRI than with pathology. Seven of 33 patients demonstrated normal posttreatment MRI nodal status (yrN0). Of these 7 yrN0, 3 exhibited no metastasis on final pathology (ypN0), 2 ypN1 and 2 ypN2. Reciprocally, MRI diagnosed 3 cases of ypN0 as yrN + . Diffusion -weighted imaging (DWI) was the only axillary node characteristic significant when associated with pathological node status (χ2(4) = 8.118, P = .072). CONCLUSION: Performance characteristics of MRI were not completely sufficient to preclude surgical axillary staging. To our knowledge, this is the first study on MRI LN assessment following NET in locally advanced breast cancer, and further studies with larger sample sizes are required to consolidate the results of this preliminary study. TRIAL REGISTRATION: Institutional Review Board approval was obtained (this current manuscript is from a prospective, open-label, randomized single-center cohort substudy of the NEOLETEXE trial). NEOLETEXE, a phase 2 clinical trial, was registered on March 23rd, 2015 in the National trial database of Norway and approved by the Regional Ethical Committee of the South-Eastern Health Region in Norway; registration number: REK-SØ-84-2015 .

Explainable Artificial Intelligence for Human-Machine Interaction in Brain Tumor Localization.

Primary malignancies in adult brains are globally fatal. Computer vision, especially recent developments in artificial intelligence (AI), have created opportunities to automatically characterize and diagnose tumor lesions in the brain. AI approaches have provided scores of unprecedented accuracy in different image analysis tasks, including differentiating tumor-containing brains from healthy brains. AI models, however, perform as a black box, concealing the rational interpretations that are an essential step towards translating AI imaging tools into clinical routine. An explainable AI approach aims to visualize the high-level features of trained models or integrate into the training process. This study aims to evaluate the performance of selected deep-learning algorithms on localizing tumor lesions and distinguishing the lesion from healthy regions in magnetic resonance imaging contrasts. Despite a significant correlation between classification and lesion localization accuracy (R = 0.46, p = 0.005), the known AI algorithms, examined in this study, classify some tumor brains based on other non-relevant features. The results suggest that explainable AI approaches can develop an intuition for model interpretability and may play an important role in the performance evaluation of deep learning models. Developing explainable AI approaches will be an essential tool to improve human-machine interactions and assist in the selection of optimal training methods.

Low diagnostic accuracy and inter-observer agreement on CT and MRI in diagnosis of spinal fractures in multiple myeloma.

Skeletal disease is common in multiple myeloma. We investigated the inter-observer agreement and diagnostic accuracy of spinal fractures diagnosed by computer tomography (CT) and magnetic resonance imaging (MRI) from 12 myeloma patients. Two radiologists independently assessed the images. CT, MRI, and other images were combined to a gold standard. The inter-observer agreement was assessed with Cohen's kappa. Radiologist 1 diagnosed 20 malignant spinal fractures on CT and 26 on MRI, while radiologist 2 diagnosed 12 malignant spinal fractures on CT and 22 on MRI. In comparison the gold standard diagnosed 10 malignant spinal fractures. The sensitivity for malignant fractures varied from 0.5 to 1 for CT and MRI, and the specificity varied from 0.17 to 0.67. On MRI, the specificity for malignant spinal fractures was 0.17 for both radiologists. The inter-observer agreement for malignant spinal fractures on CT was -0.42 (Cohen's kappa) and -0.13 for MRI, while for osteoporotic fractures it was -0.24 for CT and 0.53 for MRI. We conclude that malignant spinal fractures were over-diagnosed on CT and MRI. The inter-observer agreement was extremely poor.

Correlation between MRI morphological response patterns and histopathological tumor regression after neoadjuvant endocrine therapy in locally advanced breast cancer: a randomized phase II trial.

PURPOSE: To correlate MRI morphological response patterns with histopathological tumor regression grading system based on tumor cellularity in locally advanced breast cancer (LABC)-treated neoadjuvant with third-generation aromatase inhibitors. METHODS: Fifty postmenopausal patients with ER-positive/HER-2-negative LABC treated with neoadjuvant letrozole and exemestane given sequentially in an intra-patient cross-over regimen for at least 4 months with MRI response monitoring at baseline as well as after at least 2 and 4 months on treatment. The MRI morphological response pattern was classified into 6 categories: 0/complete imaging response; I/concentric shrinkage; II/fragmentation; III/diffuse; IV/stable; and V/progressive. Histopathological tumor regression was assessed based on the recommendations from The Royal College of Pathologists regarding tumor cellularity. RESULTS: Following 2 and 4 months with therapy, the most common MRI pattern was pattern II (24/50 and 21/50, respectively). After 4 months on therapy, the most common histopathological tumor regression grade was grade 3 (21/50). After 4 months an increasing correlation is observed between MRI patterns and histopathology. The overall correlation, between the largest tumor diameter obtained from MRI and histopathology, was moderate and positive (r = 0.50, P-value = 2e-04). Among them, the correlation was highest in type IV (r = 0.53). CONCLUSION: The type II MRI pattern "fragmentation" was more frequent in the histopathological responder group; and types I and IV in the non-responder group. Type II pattern showed the best endocrine responsiveness and a relatively moderate correlation between sizes obtained from MRI and histology, whereas type IV pattern indicated endocrine resistance but the strongest correlation between MRI and histology.

Breast sarcoidosis: Clinical features, imaging, and histological findings.

Breast sarcoidosis is an extremely rare entity (about 1%). Conventional imaging significantly contributes to the detection of breast lesions, but it has been unable to establish a definite diagnosis. Histological examination should be mandatory, over imaging assessments, in order to confirm an early diagnosis and to avoid unjustified treatments. Malignancy should be excluded as a primary differential diagnosis. However, in the presence of granulomas, it is important to recognize other granulomatous disorders such as tuberculosis, Wegener's granulomatosis, or idiopathic granulomatous mastitis, since therapeutic strategies differ. This report clarifies the current clinical assessments and differential diagnosis of breast sarcoidosis.

Predictors of pneumothorax and chest drainage after percutaneous CT-guided lung biopsy: A prospective study.

OBJECTIVES: We present an analysis of predictors of pneumothorax, and pneumothorax requiring chest drainage after CT-guided lung biopsy, in one of the largest Scandinavian dataset presented. METHODS: We prospectively registered 875 biopsy procedures from 786 patients in one institution from January 27, 2012, to March 1, 2017, and recorded complications including pneumothorax with or without chest drainage, and multiple variables we assumed could be associated with complications. We performed multivariable logistic regression analysis to identify predictors of pneumothorax and pneumothorax requiring chest drainage. RESULTS: Of the biopsied lesions, 65% were malignant, 29% benign, and 6% inconclusive. Pneumothorax occurred in 39% of the procedures and chest drainage was performed in 10%. In multivariable analysis, significant predictors of pneumothorax were emphysema (OR 1.92), smaller lesion size (OR 0.83, per 1 cm increase in lesion size), lateral body position during procedure (OR 2.00), longer needle time (OR 1.09, per minute), repositioning of coaxial needle with new insertion through pleura (OR 3.04), insertion through interlobar fissure (OR 5.21), and shorter distance to pleura (OR 0.79, per 1 cm increase in distance). Predictors of chest drainage were emphysema (OR 4.01), lateral body position (OR 2.61), and needle insertion through interlobar fissure (OR 4.17). CONCLUSION: Predictors of pneumothorax were emphysema, lateral body position, needle insertion through interlobar fissure, repositioning of coaxial needle with new insertion through pleura, and shorter distance to pleura. The finding of lateral body position as a predictor of pneumothorax is not earlier described. Emphysema, lateral body position, and needle insertion through interlobar fissure were also predictors of chest drainage. KEY POINTS: • Pneumothorax is a frequent complication to CT-guided lung biopsy; a smaller fraction of these complications needs chest drainage. • Predictors for pneumothorax are emphysema, smaller lesion size, lateral body position, longer needle time, repositioning of coaxial needle with new insertion through pleura, needle insertion through the interlobar fissure, and shorter distance to pleura. • Predictors for requirement for chest drainage post CT-guided lung biopsy are emphysema, lateral body position, and needle insertion through the interlobar fissure.

Accuracy of breast MRI in patients receiving neoadjuvant endocrine therapy: comprehensive imaging analysis and correlation with clinical and pathological assessments.

PURPOSE: To assess the accuracy of magnetic resonance imaging (MRI) measurements in locally advanced oestrogen receptor-positive and human epidermal growth factor receptor 2-negative breast tumours before, during and after neoadjuvant endocrine treatment (NET) for evaluation of tumour response in comparison with clinical and pathological assessments. METHODS: This prospective study enrolled postmenopausal patients treated neoadjuvant with letrozole and exemestane given sequentially in an intra-patient cross-over regimen. Fifty-four patients were initially recruited, but only 35 fulfilled the inclusion criteria and confirmed to participate with a median age of 77. Tumours were scanned with MRI prior to treatment, during the eighth week of treatment and prior to surgery. Additionally, changes in longest diameter on clinical examination (CE) and tumour size at pathology were determined. Pre- and post-operative measurements of tumour size were compared in order to evaluate tumour response. RESULTS: The correlation between post-treatment MRI size and pathology was moderate and higher with a correlation coefficient (r) 0.64 compared to the correlation between CE and pathology r = 0.25. Post-treatment MRI and clinical results had a negligible bias towards underestimation of lesion size. Tumour size on MRI and CE had 0.82 cm and 0.52 cm lower mean size than tumour size measured by pathology, respectively. CONCLUSIONS: The higher correlation between measurements of residual disease obtained on MRI and those obtained with pathology validates the accuracy of imaging assessment during NET. MRI was found to be more accurate for estimating complete responses than clinical assessments and warrants further investigation in larger cohorts to validate this finding.

Radiological evaluation of primary breast sarcoidosis presenting as bilateral breast lesions.

Sarcoidosis is an idiopathic multisystemic inflammatory disease that may exceptionally involve the breast and can have imaging features suspicious for benign or malignant lesions. Biopsy should be required to distinguish between breast sarcoidosis and malignancy, because clinical, mammographic and sonographic findings can be ambiguous or inconclusive. This case discusses the radiological manifestations and the value of different diagnostic features, and names the most relevant differential diagnosis.

CT guided neurolytic blockade of the coeliac plexus in patients with advanced and intractably painful pancreatic cancer.

BACKGROUND AND AIMS: Pain caused by infiltrating pancreatic cancer is complex in nature and may therefore be difficult to treat. In addition to conventional analgesics, neurolytic blockade of the coeliac plexus is often recommended. However, different techniques are advocated, and procedures vary, and the results may therefore be difficult to compare. Therefore strong evidence for the effect of this treatment is still lacking, and more studies are encouraged. Our aim was to describe our technique and procedures using a Computer Tomograph (CT) guided procedure with a dorsal approach and present the results. METHODS: The procedures were performed in collaboration between a radiologist and an anaesthesiologist. All patients had advanced pancreatic cancer. The patients were placed in prone position on pillows, awake and monitored. Optimal placement of injection needles was guided by CT, and the radiologist injected a small dose of contrast as a control. When optimal needle position, the anaesthesiologist took over and completed the procedure. At first 40 mg methylprednisolone was injected to prevent inflammation. Thereafter a mixture of 99% ethanol diluted to 50% by ropivacaine 7.5 mg/mL to a total amount of 20-30 mL per needle was slowly injected. Repeated aspiration was performed during injection to avoid intravasal injection. Pain treatment and pain score was recorded and compared before and after the treatment. RESULTS: Eleven procedures in 10 patients were performed. Age 49-75, mean 59 years. Median rest life time was 36 days (11-140). Significant reduction of analgesics was observed 1 week after the procedure, and most patients also reported reduction of pain. No serious side effects were observed. CONCLUSIONS: CT guided neurolytic celiac plexus blockade is a safe and effective treatment for intractable pain caused by advanced pancreatic cancer. Not all patients experience a significant effect, but the side effects are minor, and the procedure should therefore be offered patients experiencing intractable cancer related pain.

The clinical value of routine whole-body magnetic resonance imaging (MRI) in palliative care.

BACKGROUND: Whole-body MRI (WBMRI) has become an accessible method for detecting different types of pathologies both in the skeleton and the viscera, which may explain painful conditions, for example tumors and inflammation. PURPOSE: To assess a possible value of using WBMRI in order to improve palliative care. MATERIAL AND METHODS: Twenty patients (all eligible patients) admitted to the Department for Palliative Care were consecutively included in this study. They underwent a modified WBMRI, with fewer and shorter pulse sequences than in a standard WBMRI, to reduce patient stress. However, the patients' physicians were to exclude patients where little might be obtained and discomfort, distress, and pain could be induced. The treating physicians registered clinical utility directly after receiving the MRI report in a questionnaire. The registration was repeated after ended treatment. RESULTS: Eighty percent had new findings detected, and 40% of the patients had a change in treatment due to the MRI result, mainly changes in analgesics and/or radiation therapy. CONCLUSION: The WBMRI helped the clinicians to improve treatment and a majority of the patients benefited from this. In eight patients the treatment was changed due to the results. The clinical value (utility) was indicated to be high.

A noncontrast-enhanced pulse sequence optimized to visualize human peripheral vessels.

The purpose of this paper is to present a pulse sequence optimized to visualize human peripheral vessels. The optimized MR technique is a 3D multi-shot balanced non-SSFP gradient echo pulse sequence with fat suppression. Several imaging parameters were adjusted to find the best compromise between the contrast of vascular structures and muscle, fat, and bone. Most of the optimization was performed in the knee and calf regions using multi-channel SENSE coils. To verify potential clinical use, images of both healthy volunteers and volunteers with varicose veins were produced. The balanced non-SSFP sequence can produce high-spatial-resolution images of the human peripheral vessels without the need for an intravenous contrast agent. Both arteries and veins are displayed along with other body fluids. Due to the high spatial resolution of the axial plane source or reconstructed images, the need for procedures to separate arteries from veins is limited. We demonstrate that high signals from synovial joint fluid and cystic structures can be suppressed by applying an inversion prepulse but at the expense of reduced image signal-to-noise and overall image quality.

[Secretin stimulated magnetic resonance cholangiopancreatography in diseases of the biliary and pancreatic ducts]. / Sekretinstimulert magnetisk resonanskolangiopankreatografi ved lidelser i galle--og pancreasganger.

BACKGROUND: MRCP has replaced ERCP as the diagnostic tool in diseases in the biliary and pancreatic ducts. Secretin increases the secretion to ducts, and this has been reported to improve MRCP image quality. MATERIAL AND METHODS: We report our experience with S-MRCP in our first 20 patients. Secretin was given intravenously and images were obtained every minute for 10 minutes. These images were compared with MRCP images taken before and after secretin stimulation. RESULTS: New information was yielded in 18 cases, i.e. information not observed in previous radiological examinations. INTERPRETATION: In diagnostics of dysfunction of the sphincter of Oddi, the method may be useful, given the functional aspect of the procedure where increased pressure in the ducts may lead to pain. It may further improve the diagnostics of pancreatic cancer versus pancreatitis, in pancreas divisum and sclerosing cholangitis. The method is also valuable for clarifying whether there is injury to the pancreatic duct after blunt abdominal trauma. Surgical common bile duct injuries may be better assessed than with any other method. In difficult pancreatic and biliary investigations, S-MRCP seems to be a useful and complication-free supplement to existing diagnostic methods.