Comparison of Radiologists and Other Specialists in the Performance of Lumbar Puncture Procedures Over Time.

BACKGROUND AND PURPOSE: Lumbar punctures may be performed by many different types of health care providers. We evaluated the percentages of lumbar punctures performed by radiologists-versus-nonradiologist providers, including changes with time and discrepancies between specialties. MATERIALS AND METHODS: Lumbar puncture procedure claims were identified in a 5% sample of Medicare beneficiaries from 2004 to 2017 and classified by provider specialty, site of service, day of week, and patient complexity. Compound annual growth rates for 2004 versus 2017 were calculated; t test and χ2 statistical analyses were performed. RESULTS: Lumbar puncture use increased from 163.3 to 203.4 procedures per 100,000 Medicare beneficiaries from 2004 to 2017 (overall rate, 190.3). Concurrently, the percentage of lumbar punctures performed by radiologists increased from 37.1% to 54.0%, while proportions performed by other major physician specialty groups either declined (eg, neurologists from 23.5% to 10.0%) or were largely unchanged. While radiologists saw the largest absolute increase in the percentage of procedures, the largest relative increase occurred for nonphysician providers (4.2% in 2004 to 7.5% in 2017; +78.6%). In 2017, radiologists performed most procedures on weekdays (56.2%) and a plurality on weekends (38.2%). Comorbidity was slightly higher in patients undergoing lumbar puncture by radiologists (P < .001). CONCLUSIONS: Radiologists now perform most lumbar puncture procedures for Medicare beneficiaries in both the inpatient and outpatient settings. The continuing shift in lumbar puncture responsibility from other specialists to radiologists has implications for clinical workflows, cost, radiation exposure, and postgraduate training.

Board Certification Characteristics of Practicing Neuroradiologists.

BACKGROUND AND PURPOSE: Insight into the status of neuroradiology subspecialty certification across the United States could help to understand neuroradiologists' perceived value of subspecialty certification as well as guide efforts to optimize pathways for broader voluntary certification participation. Our aim was to assess board certification characteristics of practicing US neuroradiologists. MATERIALS AND METHODS: The American Board of Radiology public search engine was used to link Medicare-participating radiologists with American Board of Radiology diplomates. Among linked diplomates, 4670 neuroradiologists were identified on the basis of 3 criteria: current or prior neuroradiology subspecialty certification or currently >50% clinical work effort in neuroradiology based on work relative value unit-weighted national Medicare claims ("majority-practice neuroradiologists"). Subspecialty certification status was studied in each group, using Centers for Medicare & Medicaid Services data to identify additional physician characteristics. RESULTS: Of 3769 included radiologists ever subspecialty certified, 84.1% are currently subspecialty certified. Of 1777/3769 radiologists ever subspecialty-certified and with lifetime primary certificates (ie, nonmandated Maintenance of Certification), only 66.6% are currently subspecialty certified. Of 3341 included majority-practice neuroradiologists, 73.0% were ever subspecialty certified; of these, 89.1% are currently subspecialty certified. Of 3341 majority-practice neuroradiologists, the fraction currently subspecialty certified was higher for those in academic (81.3%) versus nonacademic (58.2%) practices, larger versus smaller practices (72.1% for those in ≥100 versus 36.1% for <10-member practices), US regions other than the West (64.1%-70.6% versus 56.5%), fewer years in practice (77.5% for 11-20 years versus 31.3% for >50 years), and time-limited (73.5%) versus lifetime (54.9%) primary certificates. CONCLUSIONS: More than one-quarter of majority-practice neuroradiologists never obtained neuroradiology subspecialty certification. Even when initially obtained, that certification is commonly not maintained, particularly by lifetime primary certificate diplomates and those in nonacademic and smaller practices. Further investigation is warranted to better understand neuroradiologists' decisions regarding attaining and maintaining subspecialty certification.

PI-RADS version 2.1: one small step for prostate MRI.

Multiparametric (mp) prostate magnetic resonance imaging (MRI) is playing an increasingly prominent role in the diagnostic work-up of patients with suspected prostate cancer. Performing mpMRI before biopsy offers several advantages including biopsy avoidance under certain clinical circumstances and targeting biopsy of suspicious lesions to enable the correct diagnosis. The success of the technique is heavily dependent on high-quality image acquisition, interpretation, and report communication, all areas addressed by previous versions of the Prostate Imaging-Reporting and Data System (PI-RADS) recommendations. Numerous studies have validated the approach, but the widespread adoption of PI-RADS version 2 has also highlighted inconsistencies and limitations, particularly relating to interobserver variability for evaluation of the transition zone. These limitations are addressed in the recently released version 2.1. In this article, we highlight the key changes proposed in PI-RADS v2.1 and explore the background reasoning and evidence for the recommendations.

Does normalisation improve the diagnostic performance of apparent diffusion coefficient values for prostate cancer assessment? A blinded independent-observer evaluation.

AIM: To evaluate the performance of normalised apparent diffusion coefficient (ADC) values for prostate cancer assessment when performed by independent observers blinded to histopathology findings. MATERIALS AND METHODS: Fifty-eight patients undergoing 3 T phased-array coil magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI; maximal b-value 1000 s/mm(2)) before prostatectomy were included. Two radiologists independently evaluated the images, unaware of the histopathology findings. Regions of interest (ROIs) were drawn within areas showing visually low ADC within the peripheral zone (PZ) and transition zone (TZ) bilaterally. ROIs were also placed within regions in both lobes not suspicious for tumour, allowing computation of normalised ADC (nADC) ratios between suspicious and non-suspicious regions. The diagnostic performance of ADC and nADC were compared. RESULTS: For PZ tumour detection, ADC achieved significantly higher area under the receiver operating characteristic curve (AUC; p=0.026) and specificity (p=0.021) than nADC for reader 1, and significantly higher AUC (p=0.025) than nADC for reader 2. For TZ tumour detection, nADC achieved significantly higher specificity (p=0.003) and accuracy (p=0.004) than ADC for reader 2. For PZ Gleason score >3+3 tumour detection, ADC achieved significantly higher AUC (p=0.003) and specificity (p=0.005) than nADC for reader 1, and significantly higher AUC (p=0.023) than nADC for reader 2. For TZ Gleason score >3+3 tumour detection, ADC achieved significantly higher specificity (p=0.019) than nADC for reader 1. CONCLUSION: In contrast to prior studies performing unblinded evaluations, ADC was observed to outperform nADC overall for two independent observers blinded to the histopathology findings. Therefore, although strategies to improve the utility of ADC measurements in prostate cancer assessment merit continued investigation, caution is warranted when applying normalisation to improve diagnostic performance in clinical practice.

Assessment of change in prostate volume and shape following surgical resection through co-registration of in-vivo MRI and fresh specimen ex-vivo MRI.

AIM: To compare the size and shape of the prostate between in-vivo and fresh ex-vivo magnetic resonance imaging (MRI), in order to quantify alterations in the prostate resulting from surgical resection. MATERIAL AND METHOD: Ten patients who had undergone 3 T prostate MRI using a phased-array coil and who were scheduled for prostatectomy were included in this prospective study. The ex-vivo specimen underwent MRI prior to formalin fixation or any other histopathological processing. Prostate volume in vivo and ex vivo was assessed using planimetry. Prostate shape was assessed by calculating ratios between the diameters of the prostate in all three dimensions. RESULTS: Mean prostate volume was significantly smaller ex vivo than in vivo (39.7 ± 18.6 versus 50.8 ± 26.8 cm(3); p = 0.008), with an average change in volume of -19.5%. The right-to-left (RL)/anteroposterior (AP) ratio of the prostate, representing the shape of the prostate within its axial plane, was significantly larger ex vivo than in vivo (1.33 ± 0.14 versus 1.21 ± 0.12; p = 0.015), with an average percent change in RL/AP ratio of the prostate of +12.2%. There was no significant difference between in-vivo and ex-vivo acquisitions in terms of craniocaudal (CC)/AP (p = 0.963, median change = -2.1%) or RL/CC (p = 0.265, median change = +1.3%) ratios. CONCLUSION: The observed volume and shape change following resection has not previously been assessed by comparison of in-vivo and fresh ex-vivo MRI and likely represents loss of vascularity and of connective tissue attachments in the ex-vivo state. These findings have implications for co-registration platforms under development to facilitate improved understanding of the accuracy of MRI in spatial localization of prostate tumours.

How "consistent" is "consistent"? A clinician-based assessment of the reliability of expressions used by radiologists to communicate diagnostic confidence.

AIM: To evaluate the degree of variability in clinicians' interpretation of expressions used by radiologists to communicate their level of diagnostic confidence within radiological reports. MATERIALS AND METHODS: Clinicians were solicited to complete a prospective survey asking them to select the approximate perceived level of certainty, expressed as a percentage, associated with 20 expressions used by radiologists to communicate their level of diagnostic confidence within radiological reports. The median and inter-decile range (IDR) were computed for each expression, with a smaller IDR indicating greater reproducibility. Clinicians were also asked questions regarding their attitudes about radiologists' communication of diagnostic confidence. RESULTS: Forty-nine surveys were completed. Median confidence associated with the expressions ranged from 10-90%. Reproducibility of the expressions was variable, as IDR ranged from 15-53%, although a median IDR of 40% indicated overall poor reproducibility. Expressions with relatively higher reproducibility included "most likely", "likely", and "unlikely" (IDR 15-20%), whereas expressions with relatively lower reproducibility included "compatible with", "suspicious for", "possibly," and "can be seen in the setting of" (IDR ≥45%). Only 20% of clinicians agreed or strongly agreed that radiologists consistently use such expressions within their reports. Fifty-five percent of clinicians preferred that diagnostic confidence be communicated as a percentage rather than as a textual expression. CONCLUSION: There was poor reproducibility in clinicians' interpretations of many expressions used by radiologists to communicate their level of diagnostic confidence. Use of percentages to convey diagnostic confidence within reports may mitigate this source of ambiguity in radiologists' communication with clinicians.

Prevalence of pelvic organ prolapse detected at dynamic MRI in women without history of pelvic floor dysfunction: comparison of two reference lines.

AIM: To retrospectively evaluate the prevalence of pelvic organ prolapse as an incidental finding on dynamic magnetic resonance imaging (MRI) using two different references lines. MATERIALS AND METHODS: Sixty women with symptoms unrelated to pelvic floor dysfunction who underwent MRI including a dynamic sagittal true fast imaging with steady-state free precession (TrueFISP) sequence during straining were identified. Two radiologists in consensus used the pubococcygeal line (PCL) and mid-pubic line (MPL) to diagnose and grade prolapse in all three pelvic compartments. RESULTS: Cystocele was absent, mild, moderate, and severe in 88% (53/60), 7% (4/60), 5% (3/60), and 0% (0/60) of patients, respectively, using PCL, versus 78% (47/60), 13% (8/60), 5% (3/60), and 3% (2/60) of patients, respectively, using MPL. Vaginal prolapse was absent, mild, moderate, and severe in 95% (57/60), 5% (3/60), 0% (0/60), and 0% (0/60) of patients, respectively, using PCL, versus 80% (48/60), 17% (10/60), 3% (2/60), and 0% (0/60) of patients, respectively, using MPL. Rectal descent was absent, mild, moderate, and severe in 63% (38/60), 10% (6/60), 23% (14/60), and 3% (2/60) of patients, respectively, using PCL, versus 43% (26/60), 27% (16/60), 27% (16/60), and 3% (2/60) of patients, respectively, using MPL. No enterocele, peritoneocele, or muscular defect was identified. Two percent (1/60) of patients had mild rectocele, 8% (5/60) had abnormal vesico-urethral angle, and 25% (15/60) had abnormal levator plate angle. CONCLUSION: In asymptomatic women, dynamic MRI identified the greatest degrees of prolapse in the posterior compartment. The MPL consistently yielded greater frequency of prolapse than the PCL. Findings of pelvic organ prolapse may be observed in asymptomatic patients and are of uncertain significance, requiring correlation with clinical and physical examination findings.

Preliminary experience with a novel method of three-dimensional co-registration of prostate cancer digital histology and in vivo multiparametric MRI.

AIM: To assess a novel method of three-dimensional (3D) co-registration of prostate cancer digital histology and in-vivo multiparametric magnetic resonance imaging (mpMRI) image sets for clinical usefulness. MATERIAL AND METHODS: A software platform was developed to achieve 3D co-registration. This software was prospectively applied to three patients who underwent radical prostatectomy. Data comprised in-vivo mpMRI [T2-weighted, dynamic contrast-enhanced weighted images (DCE); apparent diffusion coefficient (ADC)], ex-vivo T2-weighted imaging, 3D-rebuilt pathological specimen, and digital histology. Internal landmarks from zonal anatomy served as reference points for assessing co-registration accuracy and precision. RESULTS: Applying a method of deformable transformation based on 22 internal landmarks, a 1.6 mm accuracy was reached to align T2-weighted images and the 3D-rebuilt pathological specimen, an improvement over rigid transformation of 32% (p = 0.003). The 22 zonal anatomy landmarks were more accurately mapped using deformable transformation than rigid transformation (p = 0.0008). An automatic method based on mutual information, enabled automation of the process and to include perfusion and diffusion MRI images. Evaluation of co-registration accuracy using the volume overlap index (Dice index) met clinically relevant requirements, ranging from 0.81-0.96 for sequences tested. Ex-vivo images of the specimen did not significantly improve co-registration accuracy. CONCLUSION: This preliminary analysis suggests that deformable transformation based on zonal anatomy landmarks is accurate in the co-registration of mpMRI and histology. Including diffusion and perfusion sequences in the same 3D space as histology is essential further clinical information. The ability to localize cancer in 3D space may improve targeting for image-guided biopsy, focal therapy, and disease quantification in surveillance protocols.

Pancreatic cancer: lack of association between apparent diffusion coefficient values and adverse pathological features.

AIM: To identify retrospectively potential associations between apparent diffusion coefficient (ADC) values of pancreatic adenocarcinoma and tumour grade as well as other pathological features, using histopathological assessment from the Whipple procedure as the reference standard. MATERIALS AND METHODS: Thirty patients with pancreatic adenocarcinoma underwent magnetic resonance imaging (MRI) including diffusion-weighted imaging with b-values of 0 and 500 s/mm(2) before the Whipple procedure. Two radiologists independently recorded the ADC values of the tumour and benign pancreas for all cases. ADC values were compared with histopathological findings following the Whipple procedure. RESULTS: The intra-class correlation coefficient was 0.689 for benign pancreas and 0.695 for tumours, indicating good inter-reader agreement for ADC values. The mean ADC value was significantly lower in tumours than in benign pancreas for both readers (reader 1: 1.74 ± 0.34 × 10(-3) mm(2)/s versus 2.08 ± 0.48 × 10(-3) mm(2)/s, respectively, p = 0.006; reader 2: 1.69 ± 0.41 × 10(-3) mm(2)/s versus 2.11 ± 0.54 × 10(-3) mm(2)/s, respectively, p < 0.001). However, there was no significant difference in mean ADC between poorly and well/moderately differentiated tumours for either reader (reader 1: 1.69 ± 0.36 × 10(-3) mm(2)/s versus 1.78 ± 0.33 × 10(-3) mm(2)/s, respectively, p = 0.491; reader 2: 1.62 ± 0.33 × 10(-3) mm(2)/s versus 1.75 ± 0.49 × 10(-3) mm(2)/s, respectively, p = 0.405). The area under the curve (AUC) for differentiation of poorly and well/moderately differentiated tumours was 0.611 and 0.596 for readers 1 and 2, respectively, and was not significantly better than an AUC of 0.500 for either reader (p ≥ 0.306). In addition, ADC was not significantly different for either reader between tumours with stage T3 versus stage T1/T2, between tumours with and without metastatic peri-pancreatic lymph nodes, or between tumours located in the pancreatic head versus other pancreatic regions (p ≥ 0.413). CONCLUSION: No associations between ADC values of pancreatic adenocarcinoma and tumour grade or other adverse pathological features were observed.

Infiltrative hepatocellular carcinoma: comparison of MRI sequences for lesion conspicuity.

AIM: To characterize the magnetic resonance imaging (MRI) features of infiltrative hepatocellular carcinoma (I-HCC), with emphasis on its relative conspicuity on different sequences. MATERIALS AND METHODS: Nineteen patients exhibiting HCC with non-mass-like appearance and ill-defined margins, and who died within 1 year following diagnosis of I-HCC, were included. For each sequence, two observers independently assessed the lesion's signal intensity relative to benign liver as well as subjective visual conspicuity. The observers also selected the sequence exhibiting the greatest visual conspicuity. A separate radiologist placed regions of interest to measure tumour-to-liver contrast for each lesion. Tumour size and clinical features were also assessed. RESULTS: Eighteen of the 19 patients exhibited central portal vein tumour thrombus; eight of the 19 patients had metastatic disease. All I-HCC measured over 5 cm. The two observers identified hyperintensity on T2-weighted imaging (WI) in 19 and 19 cases, hyperintensity on high b-value diffusion-weighted imaging (DWI) in 18 and 19 cases, arterial-phase hyperintensity in six and 10 cases, and venous-phase hypo-intensity in 17 and 16 cases. T2WI, DWI, and venous-phase images exhibited significantly greater subjective visual conspicuity than arterial-phase images for both observers (all p ≤ 0.040). Also, T2WI and DWI tended to exhibit greater tumour-to-liver contrast than arterial- and venous-phase images (all p ≤ 0.055). The arterial-phase was not selected as having greatest conspicuity for any case by either reader. CONCLUSION: I-HCC is an aggressive form of HCC that is often less conspicuous on arterial-phase images than typical mass-forming HCC; T2WI and DWI may be more useful sequences for its diagnosis. Awareness of the distinct imaging features of I-HCC may be important for proper diagnosis.

Impact of delay after biopsy and post-biopsy haemorrhage on prostate cancer tumour detection using multi-parametric MRI: a multi-reader study.

AIM: To assess impact of haemorrhage and delay after biopsy on prostate tumour detection using multi-parametric (MP) magnetic resonance imaging (MRI) assessment. MATERIALS AND METHODS: Forty-four patients underwent prostate MRI at 1.5 T using a pelvic phased-array coil, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging, before prostatectomy. Three radiologists independently reviewed images during four sessions [T2WI, DWI, DCE, and all parameters combined (MP-MRI)] to assess for tumour in each sextant. In a separate session, readers reviewed T1WI to score the extent of haemorrhage per sextant. Accuracy was assessed using logistic regression for correlated data. RESULTS: There was no significant difference in accuracy between readers for any session (p ≥ 0.166), and results were averaged across the three readers for remaining comparisons. Accuracy was significantly greater for MP-MRI than for any parameter alone (p ≤ 0.020). For T2WI alone, there was a trend toward decreased sensitivity in sextants with extensive haemorrhage (p = 0.072). However, accuracy, sensitivity, and specificity were otherwise similar for sextants with and without extensive haemorrhage for all sessions (p = 0.192-0.934). No session showed a significant improvement in accuracy, sensitivity, or specificity in cases with delay after biopsy of over 4 weeks compared with shorter delay. CONCLUSION: Extensive haemorrhage and short delay after biopsy did not negatively impact accuracy for tumour detection using MP-MRI. Further studies using MP-MRI protocols and interpretation schemes from other institutions are required to confirm these observations.

Breath-hold T2-weighted MRI of the liver at 3T using the BLADE technique: impact upon image quality and lesion detection.

AIM: To compare image quality and lesion detection in the liver using magnetic resonance imaging (MRI) at 3T between T2-weighted imaging using a standard rectilinear k-space trajectory (standard T2WI) and using the BLADE technique (BLADE-T2WI), a technique that employs periodically rotated overlapping parallel lines with enhanced reconstruction for motion correction. MATERIALS AND METHODS: Twenty-eight consecutive patients who underwent MRI examination of the liver at 3T including standard T2WI and BLADE-T2WI, both performed using multiple breath-holds, comprised the study cohort. Images were reviewed in consensus by two radiologists during separate sessions for a number of measures regarding artefacts and image quality. These two readers also assessed the two image sets for the presence of liver lesions and measured liver-to-lesion contrast. Binary logistic regression for correlated data was used to compare the sequences in terms of sensitivity and positive predictive value (PPV) for lesion detection. RESULTS: BLADE-T2WI received significantly higher scores than did standard T2WI for in-plane respiratory motion (p=0.0195), other ghosting artefacts (p<0.0001), sharpness of the liver edge (p=0.0004), sharpness of intra-hepatic vessels (p<0.0001), flow signal suppression (p<0.0001), and overall image quality (p<0.0001). There was a non-significant trend toward improved B(1)-inhomogeneity artefact with BLADE-T2WI (p=0.0571). There was no difference in through-plane respiratory motion (p=0.6836). BLADE-T2WI demonstrated a significant improvement in PPV for lesion detection (p=0.0129) as well as in liver-to-lesion contrast (p=0.0054). There was no difference regarding lesion sensitivity (p=1.0). CONCLUSIONS: Use of the BLADE technique for T2-weighted MRI of the liver at 3T may lead to a significant improvement in image artefacts and improved PPV for lesion detection.

MRI appearance of massive renal replacement lipomatosis in the absence of renal calculus disease.

Renal replacement lipomatosis is a rare benign entity in which extensive fibrofatty proliferation of the renal sinus is associated with marked renal atrophy. In this report, we present a case of massive renal replacement lipomatosis demonstrated on MRI. The presentation was atypical given an absence of associated renal calculus disease, and an initial CT scan was interpreted as suspicious for a liposarcoma. The differential diagnosis and key MRI findings that served to establish this specific diagnosis are reviewed. Histopathological correlation is also presented, as the patient underwent nephroureterectomy.

Imaging appearance of bulk fat within an oncocytic adrenocortical neoplasm, a rare and potentially malignant tumour.

Oncocytic adrenocortical neoplasm is a rare adrenal tumour that usually follows a benign clinical course. In some cases, however, these tumours have exhibited malignant behaviour. Here, we present the first published case showing bulk fat within an oncocytic adrenocortical neoplasm on CT and MRI, a finding that mimics fat within an adrenal myelolipoma. The distinction between these entities is important, as the current suggested management of an oncocytic adrenocortical neoplasm is resection with subsequent imaging surveillance.

CT and MRI appearance of solitary parapelvic neurofibroma of the kidney.

We report an extremely rare case of a renal parapelvic neurofibroma. The mass was an incidental finding on an abdominal CT scan of an asymptomatic 59-year-old male with hepatitis C. Subsequent MRI demonstrated a complex mass occupying the left renal sinus that had mass effect on the pelvicalyceal system. The patient underwent left radical nephrectomy, and histological and immunohistochemical findings confirmed the lesion to be a neurofibroma. Given that similar imaging features have been reported previously in four additional cases, we suggest that it may be possible to include this entity in the pre-operative differential diagnosis.