FDA-approved deep learning software application versus radiologists with different levels of expertise: detection of intracranial hemorrhage in a retrospective single-center study

PURPOSE

To assess an FDA-approved and CE-certified deep learning (DL) software application compared to the performance of human radiologists in detecting intracranial hemorrhages (ICH).

METHODS

Within a 20-week trial from January to May 2020, 2210 adult non-contrast head CT scans were performed in a single center and automatically analyzed by an artificial intelligence (AI) solution with workflow integration. After excluding 22 scans due to severe motion artifacts, images were retrospectively assessed for the presence of ICHs by a second-year resident and a certified radiologist under simulated time pressure. Disagreements were resolved by a subspecialized neuroradiologist serving as the reference standard. We calculated interrater agreement and diagnostic performance parameters, including the Breslow-Day and Cochran-Mantel-Haenszel tests.

RESULTS

An ICH was present in 214 out of 2188 scans. The interrater agreement between the resident and the certified radiologist was very high (κ = 0.89) and even higher (κ = 0.93) between the resident and the reference standard. The software has delivered 64 false-positive and 68 false-negative results giving an overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 68.2%, 96.8%, 69.5%, 96.6%, and 94.0%, respectively. Corresponding values for the resident were 94.9%, 99.2%, 93.1%, 99.4%, and 98.8%. The accuracy of the DL application was inferior (p < 0.001) to that of both the resident and the certified neuroradiologist.

CONCLUSION

A resident under time pressure outperformed an FDA-approved DL program in detecting ICH in CT scans. Our results underline the importance of thoughtful workflow integration and post-approval validation of AI applications in various clinical environments.

Delayed fenestration of Blake's pouch with or without vermian hypoplasia: fetal MRI at 3 tesla versus 1.5 tesla

Background

Fetal magnetic resonance imaging (MRI), mainly performed at standard field strength, plays a role in the classification of posterior fossa malformations. In the context of early second-trimester screening, upward rotation of the cerebellar vermis per se is usually compatible with a more favorable outcome than Dandy-Walker malformation and profound vermian hypoplasia. Delayed fenestration of Blake’s pouch may either mimic vermian hypoplasia by compression or be associated with it in individual cases. To increase specificity, there is a growing interest in the use of high-field MRI which is believed to be safe as long as the specific absorption rate is kept within accepted limits. We aim to illustrate its added value during the second and third trimester.

Case presentation

In the first case, fetal MRI at 1.5 Tesla was performed at 21 and 27 weeks’ gestation with sonographic follow up postnataly. In the second case, 3 Tesla MR images were acquired at 21 and 34 weeks’ gestation as well as in the neonatal period.

Conclusions

This pictorial case vignette supports the suggestion that mid-gestational MRI at 3 Tesla has the potential to exclude pronounced vermian hypoplasia with higher confidence than at 1.5 Tesla. However, the discrimination of mild hypoplasia from slight deformation of the cerebellar vermis will likely remain challenging.

Evaluation of a "walk-through" ladder top design during ladder-roof transitioning tasks

This study evaluated the effect of an extension ladder "walk-through" top design on kinetic and kinematic behaviors and the outward destabilizing forces induced on the ladder during transitioning at elevation. Thirty-two male participants performed stepping tasks between a ladder top and a roof at simulated elevation in a surround-screen virtual-reality system. The experimental conditions included a "walk-through" and a standard ladder top section supported on flat and sloped roof surfaces. Three force platforms were placed under the ladder section and in the roof to measure propulsion forces during transitions. A motion measurement system was used to record trunk kinematics. The frictional demand at the virtual ladder base was also calculated. The results indicate that under optimal ladder setup (angle 75.5 °), the frictional demand at the ladder base remains relatively small for all experimental conditions. Also, the "walk through" ladder top eased the ladder-to-roof transitions but not the roof-to-ladder transitions.

Behavioral disorders and cognitive impairment associated with cerebellar lesions

In the last decade evidence has accumulated that suggests that the cerebellum is involved not only in motor but also in behavioral and cognitive functions. A myriad of anatomical, clinical and imaging studies support that assumption. The lengthened survival of patients with cerebellar tumors has also brought an increased awareness of neurocognitive deficits to the neurooncological community. Although evidence from neurosurgical case series exists that clearly demonstrates that patients afflicted from posterior fossa tumors are at high risk for long-term cognitive or adaptive deficits, there is still a lack of systematic translational review on this issue. Accordingly a systematic review was conducted to summarize the impact of cerebellar lesions on behavior and cognition. The findings and clinical implications are discussed in the light of the recent advances in neuroimaging techniques.

Flat detector angio-CT following intra-arterial therapy of acute ischemic stroke: identification of hemorrhage and distinction from contrast accumulation due to blood-brain barrier disruption

BACKGROUND AND PURPOSE

Flat panel detector CT in the angiography suite may be valuable for the detection of intracranial hematomas; however, abnormal contrast enhancement frequently mimics hemorrhage. We aimed to assess the accuracy of flat panel detector CT in detecting/excluding intracranial bleeding after endovascular stroke therapy and whether it was able to reliably differentiate hemorrhage from early blood-brain barrier disruption.

MATERIALS AND METHODS

Seventy-three patients were included for retrospective evaluation following endovascular stroke therapy: 32 after stent-assisted thrombectomy, 14 after intra-arterial thrombolysis, and 27 after a combination of both. Flat panel CT images were assessed for image quality and the presence and type of intracranial hemorrhage and BBB disruption by 2 readers separately and in consensus. Follow-up by multisection head CT, serving as the reference standard, was evaluated by a single reader.

RESULTS

Conventional head CT revealed intracranial hematomas in 12 patients (8 subarachnoid hemorrhages, 7 cases of intracerebral bleeding, 3 SAHs plus intracerebral bleeding). Image quality of flat panel detector CT was considered sufficient in all cases supratentorially and in 92% in the posterior fossa. Regarding detection or exclusion of intracranial hemorrhage, flat panel detector CT reached a sensitivity, specificity, positive and negative predictive values, and accuracy of 58%, 85%, 44%, 91%, and 81%, respectively. Maximum attenuation measurements were not valuable for the differentiation of hemorrhage and BBB disruption.

CONCLUSIONS

Flat panel CT after endovascular stroke treatment was able to exclude the rare event of an intracranial hemorrhage with a high negative predictive value. Future studies should evaluate the predictive value of BBB disruptions in flat panel detector CT for the development of relevant hematomas.

Chudley-McCullough syndrome: case report and review of the neuroimaging spectrum

We report on a child with Chudley-McCullough syndrome and re-evaluate the spectrum of imaging findings (in 15 previously reported patients) which appear to be variable and, to some extent, ambiguous in the literature. Magnetic resonance imaging of the brain revealed asymmetric colpocephaly with agenesis of the splenium corporis callosi, ribbon-like subcortical gray matter heterotopia along the cingulate gyri, malrotation of both hippocampi, and dysplasia of the cerebellum. Macrocrania together with sensorineural hearing loss, colpocephaly, and posterior or complete agenesis of the corpus callosum can be considered the hallmarks of the autosomal recessive Chudley-McCullough syndrome. These may be variably associated with interhemispheric arachnoid cyst, cortical dysplasia, gray matter heterotopia, and cerebellar dysplasia. While early support with hearing aids may lead to improved language and cognitive outcome, shunting of ventricular dilatation is not indicated in the Chudley-McCullough syndrome.

[Clinical application of flat-panel CT in the angio suite]

The introduction of flat-panel detectors in modern angiographic C-arm systems makes it possible to acquire CT-like images in the angiographic suite (flat-panel CT; FD-CT). In this review, after a short technical introduction of FD-CT including the discussion of the advantages and disadvantages of this new imaging modality, the most commonly and best evaluated indications for FD-CT will be described. FD-CT has become an important adjunctive imaging modality in neurointerventional procedures and embolizations, especially during liver embolization. Another attractive indication for FD-CT is musculoskeletal interventions. FD-CT may provide important additional information in complicated peripheral vascular interventions and stent-graft procedures. FD-CT has a broad spectrum of possible applications, which finally depends on the experience and innovative thinking of the operator. However, it has to be kept in mind that FD-CT causes additional radiation exposure. Roughly, it can be assumed that currently one FD-CT sequence causes at least the same radiation exposure as one spiral CT sequence of the corresponding body region.

Aortic development and anomalies

Development of the aorta takes place during the third week of gestation. It is a complex process that can lead to a variety of congenital variants and pathological anomalies. In diagnostic and interventional radiology, knowledge of aortic abnormalities and variant branching sequence is crucially important. This article gives a systematic overview of anatomical variability of the aorta.

Postural stability effects of random vibration at the feet of construction workers in simulated elevation

The risk of falls from height on a construction site increases under conditions which degrade workers' postural control. At elevation, workers depend heavily on sensory information from their feet to maintain balance. The study tested two hypotheses: "sensory enhancement"--sub-sensory (undetectable) random mechanical vibrations at the plantar surface of the feet can improve worker's balance at elevation; and "sensory suppression"--supra-sensory (detectable) random mechanical vibrations can have a degrading effect on balance in the same experimental settings. Six young (age 20-35) and six aging (age 45-60) construction workers were tested while standing in standard and semi-tandem postures on instrumented gel insoles. The insoles applied sub- or supra-sensory levels of random mechanical vibrations to the feet. The tests were conducted in a surround-screen virtual reality system, which simulated a narrow plank at elevation on a construction site. Upper body kinematics was assessed with a motion-measurement system. Postural stability effects were evaluated by conventional and statistical mechanics sway measures, as well as trunk angular displacement parameters. Analysis of variance did not confirm the "sensory enhancement" hypothesis, but provided evidence for the "sensory suppression" hypothesis. The supra-sensory vibration had a destabilizing effect, which was considerably stronger in the semi-tandem posture and affected most of the sway variables. Sensory suppression associated with elevated vibration levels on a construction site may increase the danger of losing balance. Construction workers at elevation, e.g., on a beam or narrow plank might be at increased risk of fall if they can detect vibrations under their feet. To reduce the possibility of losing balance, mechanical vibration to supporting structures used as walking/working surfaces should be minimized when performing construction tasks at elevation.

Transsphenoidal extension of heterotopic glioneuronal tissue: pathoanatomic considerations in symptomatic neonates

PURPOSE

In this clinical investigation, we aimed (1) to re-evaluate the nature of glioneuronal tissue with transsphenoidal extension and how it fits into the nomenclature of midline malformations and mass lesions; (2) to find out if our imaging findings support current pathoanatomic concepts of clefts and canals in the sphenoid body of newborns.

METHODS

In two neonates with respiratory distress due to nasopharyngeal masses, 3T MRI was performed, and CT in one of them. Imaging features were analyzed in consensus by two pediatric neuroradiologists with histological reports being available. An interdisciplinary panel compared the findings to those of case publications and differential entities from our institutional case collection.

RESULTS

Referring to our rare case of transsphenoidal cerebral heterotopia and unique case of hypothalamic hamartoma with transsphenoidal herniation, glioneuronal heterotopia may definitely extend through the sphenoid bone. Consequently, there is reason for brain heterotopias to be labeled as such also in case of an intracranial component. Connection between heterotopic glioneuronal tissue in the nasopharynx and a hypothalamic hamartoma may go along with indistinct margins to normal brain. Neither extension through a transsphenoidal cleft nor association with a cleft palate are specific for cerebral heterotopia. Our findings support the hypothesis that transsphenoidal cerebral heterotopias do not or at least not invariably follow the route of Rathke's pouch, known as the craniopharyngeal canal.

CONCLUSION

Transsphenoidal glioneuronal heterotopia should be the top differential diagnosis in MR imaging if a non-enhancing nasopharyngeal mass of an infant extends through a craniopharyngeal cleft within the intersphenoid synchondrosis.

Fetal MRI of a hypothalamic hamartoma in Pallister-Hall syndrome

Fetal magnetic resonance imaging is increasingly being used as an adjunct to ultrasound. It allows for better visualization of in utero brain development and intracranial abnormalities (especially cerebral malformations). Hypothalamic hamartoma is a nonneoplastic malformation resembling normal hypothalamic tissue both histologically and on magnetic resonance imaging. Although it is rare, this entity is important to recognize for appropriate management and genetic counseling. We describe a unique patient in whom magnetic resonance imaging of the fetal brain allowed a prenatal diagnosis of Pallister-Hall syndrome.

FDG PET/CT in the detection of recurrent rectal cancer

The purpose of this study was to assess the additional value of combined fluorine 18 (18F)-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in the follow-up of rectal cancer after surgery. Forty-eight examinations in 30 patients were evaluated retrospectively. CT and PET components were interpreted separately, and this was followed by a consensus reading. Sites of increased FDG uptake as well as PET/CT findings were categorized as benign (1), equivocal (2), or malignant (3). The standard of reference was histology or clinical and imaging follow-up for at least 6 months. Sensitivity, specificity, positive and negative predictive values, and accuracy for differentiating benign (14/31) from malignant (17/31) uptake sites in the small pelvis were 100%, 64%, 77%, 100%, and 84% for PET/CT, and 100%, 29%, 63%, 100%, and 68% for PET, respectively. Regarding extrapelvic abnormalities, PET/CT was able to distinguish benign (31/88) from malignant (57/88) with a sensitivity, specificity, positive and negative predictive values, and accuracy of 100%, 87%, 93%, 100%, and 95%, compared with 96%, 68%, 85%, 91%, and 86% for PET. The rare case of an FDG uptake of adrenal adenoma is documented. PET/CT is valuable in the staging of rectal cancer, particularly for excluding recurrent disease suspected by PET interpretation alone in a considerable number of patients.

MR angiographic follow-up of intracranial aneurysms treated with detachable coils: evaluation of a blood-pool contrast medium

BACKGROUND AND PURPOSE

Blood-pool agents are promising in the imaging of small vessels with slow or complex flow. Our aim was to compare blood-pool contrast-enhanced MR angiography (BPCE-MRA) using gadofosveset trisodium (Vasovist) with 3D time-of-flight MRA (TOF-MRA) in the follow-up of intracranial aneurysms after endovascular therapy.

MATERIALS AND METHODS

We included 32 patients with a total of 37 coiled aneurysms. MRAs in the early steady-state phase were performed on a 1.5T scanner within 8 days of digital subtraction angiography (DSA). Two radiologists independently analyzed TOF-MRA and BPCE-MRA images. Consensus was reached by review involving a third neuroradiologist. DSA images were interpreted separately by an interventional radiologist. Findings were assigned to 1 of 3 categories: 1) complete occlusion, 2) residual neck, and 3) residual aneurysm.

RESULTS

Follow-up DSA demonstrated 13 complete obliterations (class 1), 13 residual necks (class 2), and 11 residual aneurysms (class 3). Weighted kappa statistics showed substantial concordance of TOF-MRA and DSA (0.664) as well as BPCE-MRA and DSA (0.724) ratings. Comparison between TOF-MRA and BPCE-MRA found excellent agreement (0.818) with only 6 (16.2%) discrepancies. For detecting residual flow, the difference in accuracy of both MRA techniques (83.8% versus 91.9%) was not significant (McNemar, P = 1.000). BPCE-MRA showed a tendency towards higher sensitivity and specificity (91.7% and 92.3%, respectively) compared with TOF-MRA (87.5% and 76.9%).

CONCLUSIONS

In classifying the completeness of endovascular cerebral aneurysm therapy, we found that BPCE-MRA and 3D TOF-MRA showed very good agreement. The use of Vasovist did not lead to a significantly increased accuracy of MRA follow-up.

Feasibility and potential value of flat-panel detector–based computed tomography in myelography after spinal surgery

Object

The purpose of this study was to assess the value of myelography using flat-panel detector–based computed tomography (fpCT) in 5 patients in whom the image quality of multislice CT (MSCT) or MR imaging was limited by metal artifacts.

Methods

The application of fpCT to myelographic imaging of the lumbar spine and cervicothoracic junction after surgery was feasible. Multiplanar, preferably sagittal, and 3D reconstructions adequately depicted disc space implants and provided high resolution images of osseous structures.

Results

The images obtained with fpCT allowed evaluation of anatomical details such as single nerve roots and proved especially valuable in a patient with impaired MR imaging results caused by metal artifacts from an intraoperative abrasion. In a case of recurrent disc herniation, imaging results of myelographic fpCT and MSCT scanning were in good agreement.

Conclusions

The novel imaging technique the authors describe yielded adequate results in patients with a history of spinal surgery, may be superior to MSCT scanning in depicting osseous structures and metallic implants, and has the potential to provide multilevel spinal images. Myelographic fpCT scanning may be the preferred modality in patients with expected or known metal artifacts on myelographic MSCT scans and/or MR images.

Sonography of dermatofibrosarcoma protuberans of the groin

Dermatofibrosarcoma protuberans (DFSP) is an uncommon tumor that arises from the dermis of adults. Its malignant potential is considered to be intermediate. Because the diagnosis of DFSP can frequently be suspected on the basis of physical examination reports on its sonographic appearance are rare. We report a case that highlights the value of sonography in assessing the subcutaneous extent of DFSP.

Clinical Experience with a Commercially Available Negative Oral Contrast Medium in PET/CT

PURPOSE

To evaluate a commercially available negative oral contrast material for PET/CT.

MATERIAL AND METHODS

In a prospective series of 49 patients, Mukofalk, which is a vegetarian-based substance, was used as a negative oral contrast medium in whole body PET/CT studies. Mukofalk was administered during a time period of 1.5 hours before the examination. Quality of small bowl distension and eventual pathological tracer uptake in the intestine were evaluated.

RESULTS

Distension of the small bowel was excellent or good in 41 (85 %) and poor in 8 (15 %) patients. Mild tracer uptake in the small bowel was observed in 5 patients (10.2 %) and moderate uptake in another 2 patients (4 %). In none of these patients did the F-18 FDG uptake interfere with image interpretation.

CONCLUSION

Mukofalk can be used as a negative oral contrast medium in PET/CT studies.

[Normal and disordered visual development with preferential looking]

Normal and disturbed development of grating acuity in preverbal infants has been studied using the Teller acuity card procedure. The results of 195 normal and 34 premature children are in good accordance with those reported in the literature. In more than 86% no interocular differences of grating acuity could be detected in these groups. On the other hand the incidence of interocular acuity differences reached 30% in 37 cases showing monolateral convergent squint. This is much higher than has been reported in current literature and may indicate that grating and Snellen acuity correlate better than expected in infants' squint amblyopia. As to the problem of monitoring early amblyopia therapy by PL, four longitudinal cases are presented.