Catherine C. Roberts

Accuracy of dementia diagnosis—a direct comparison between radiologists and a computerized method

There has been recent interest in the application of machine learning techniques to neuroimaging-based diagnosis. These methods promise fully automated, standard PC-based clinical decisions, unbiased by variable radiological expertise. We recently used support vector machines (SVMs) to separate sporadic Alzheimers disease from normal ageing and from fronto-temporal lobar degeneration (FTLD). In this study, we compare the results to those obtained by radiologists. A binary diagnostic classification was made by six radiologists with different levels of experience on the same scans and information that had been previously analysed with SVM. SVMs correctly classified 95% (sensitivity/specificity: 95/95) of sporadic Alzheimers disease and controls into their respective groups. Radiologists correctly classified 65–95% (median 89%; sensitivity/specificity: 88/90) of scans. SVM correctly classified another set of sporadic Alzheimers disease in 93% (sensitivity/specificity: 100/86) of cases, whereas radiologists ranged between 80% and 90% (median 83%; sensitivity/specificity: 80/85). SVMs were better at separating patients with sporadic Alzheimers disease from those with FTLD (SVM 89%; sensitivity/specificity: 83/95; compared to radiological range from 63% to 83%; median 71%; sensitivity/specificity: 64/76). Radiologists were always accurate when they reported a high degree of diagnostic confidence. The results show that well-trained neuroradiologists classify typical Alzheimers disease-associated scans comparable to SVMs. However, SVMs require no expert knowledge and trained SVMs can readily be exchanged between centres for use in diagnostic classification. These results are encouraging and indicate a role for computerized diagnostic methods in clinical practice.

Developing a Radiology Quality and Safety Program: A Primer

Four main areas of quality need to be addressed for a complete quality and safety program in radiology: safety, process improvement, professional outcome assessment, and satisfaction. These areas need to be coordinated by individuals who belong to a quality oversight committee. Management of the data can be facilitated by using a quality scorecard that posts relevant data for each operational group within a department. The ultimate goal is a cultural shift in which all departmental workers assume responsibility for quality and safety improvements and behave consistently with the core values of the organization. A road map for thinking about quality and safety issues in radiology allows all of these areas to be tied together. Four main areas of development are required, each demanding a different skill set and approach.

Carcinoma of the Stomach With Hepatocyte Differentiation (Hepatoid Adenocarcinoma)

A case of hepatoid adenocarcinoma of the stomach is reported, and the literature is reviewed. The stomach is one of the most common sites in which hepatoid adenocarcinomas have been detected. Of the 59 cases reviewed from the literature (including the current case), a 2:1 male predominance was noted, and the serum alpha-fetoprotein level was almost always increased. All patients were adults, and most had evidence of metastases at the time of resection. Prognosis seems less favorable than that associated with the more common intestinal type of adenocarcinoma of the stomach. Hepatoid adenocarcinomas typically show periodic acid-Schiff-positive, diastase-resistant intracytoplasmic globules, which are demonstrated to be positive with antibodies to alpha-fetoprotein. The tumor cells resemble liver cells, and rare cases, including our own, have evidence of bile production. In our case, messenger RNA for albumin, unique to liver cells, was demonstrated by in situ hybridization of the tumor cells.

Oblique reformation in cervical spine computed tomography: A new look at an old friend

Study Design. Cervical spine computed tomograms were evaluated for neural foraminal stenosis in both the standard axial plane and the oblique reformatted plane. Objective. To assess whether oblique reformation of cervical spine computed tomograms reduces interobserver variability in the evaluation of neural foraminal stenosis. Summary of Background Data. Radiographic assessment of neural foraminal stenosis is subjective, may vary among observers, and can affect surgical planning. Methods. The cervical spine images from 19 patients with various degrees of neural foraminal stenosis were reformatted in an oblique plane perpendicular to the long axis of the right and left neural foramens. Seven independent observers graded the degree of foraminal stenosis (none, mild [1–25%], moderate [26–75%], or severe [>75%]) and their confidence level (definite, probable, possible) on both the axial images and the oblique reformations. Results. The ages of the 12 male (mean, 67.5 ± 13.24 years) and 7 female (mean, 62.7 ± 14.79 years) patients ranged from 39 to 83 years. Interobserver variability was assessed with &khgr;2 analysis. Rates of agreement on degree of stenosis (&khgr;2 = 19.94;df = 9;P < 0.02) were significantly higher for oblique reformations. Confidence ratings also were significantly higher for oblique reformations (&khgr;2 = 18.19;df = 7;P < 0.02). Conclusions. Oblique reformation of cervical spine images significantly reduces the degree of interobserver variability and increases observer confidence in the assessment of neural foraminal stenosis. Oblique reformations should be considered in the routine evaluation of neural foraminal stenosis.

ACR Appropriateness Criteria® on Suspected Osteomyelitis in Patients With Diabetes Mellitus

Imaging of the diabetic foot is among the most challenging areas of radiology. The authors present a consensus of the suggested tests in several clinical scenarios, such as early neuropathy, soft-tissue swelling, skin ulcer, and suspected osteomyelitis. In most of these situations, magnetic resonance imaging (MRI) with or without contrast is the examination of choice. Most other imaging tests have complementary roles. For soft-tissue swelling or an ulcer, radiography and MRI with or without contrast are suggested. Bone scintigraphy with white blood cell scanning is used when MRI is contraindicated. In patients with diabetes without ulcers, radiography and MRI with or without contrast are suggested; bone scanning may be used when MRI is contraindicated.

ACR Appropriateness Criteria® on Metastatic Bone Disease

Appropriate imaging modalities for screening, staging, and surveillance of patients with suspected and documented metastatic disease to bone include (99m)Tc bone scanning, MRI, CT, radiography, and 2-[(18)F]fluoro-2-deoxyglucose-PET. Clinical scenarios reviewed include asymptomatic stage 1 breast carcinoma, symptomatic stage 2 breast carcinoma, abnormal bone scan results with breast carcinoma, pathologic fracture with known metastatic breast carcinoma, asymptomatic well-differentiated and poorly differentiated prostate carcinoma, vertebral fracture with history of malignancy, non-small-cell lung carcinoma staging, symptomatic multiple myeloma, osteosarcoma staging and surveillance, and suspected bone metastasis in a pregnant patient. No single imaging modality is consistently best for the assessment of metastatic bone disease across all tumor types and clinical situations. In some cases, no imaging is indicated. The recommendations contained herein are the result of evidence-based consensus by the ACR Appropriateness Criteria((R)) Expert Panel on Musculoskeletal Radiology.

An automated DICOM database capable of arbitrary data mining (Including Radiation Dose Indicators) for quality monitoring

The U.S. National Press has brought to full public discussion concerns regarding the use of medical radiation, specifically x-ray computed tomography (CT), in diagnosis. A need exists for developing methods whereby assurance is given that all diagnostic medical radiation use is properly prescribed, and all patients’ radiation exposure is monitored. The “DICOM Index Tracker©” (DIT) transparently captures desired digital imaging and communications in medicine (DICOM) tags from CT, nuclear imaging equipment, and other DICOM devices across an enterprise. Its initial use is recording, monitoring, and providing automatic alerts to medical professionals of excursions beyond internally determined trigger action levels of radiation. A flexible knowledge base, aware of equipment in use, enables automatic alerts to system administrators of newly identified equipment models or software versions so that DIT can be adapted to the new equipment or software. A dosimetry module accepts mammography breast organ dose, skin air kerma values from XA modalities, exposure indices from computed radiography, etc. upon receipt. The American Association of Physicists in Medicine recommended a methodology for effective dose calculations which are performed with CT units having DICOM structured dose reports. Web interface reporting is provided for accessing the database in real-time. DIT is DICOM-compliant and, thus, is standardized for international comparisons. Automatic alerts currently in use include: email, cell phone text message, and internal pager text messaging. This system extends the utility of DICOM for standardizing the capturing and computing of radiation dose as well as other quality measures.

Imaging of Chronic and Exotic Sinonasal Disease: Review

OBJECTIVE Chronic sinusitis is one of the most commonly diagnosed illnesses in the United States. The educational objectives of this review article are for the participant to exercise, self-assess, and improve his or her understanding of the imaging evaluation of sinonasal disease. CONCLUSION This article describes the anatomy, pathophysiology, microbiology, and diagnosis of sinonasal disease, including chronic and fungal sinusitis, juvenile nasopharyngeal angiofibroma, inverted papilloma, and chondrosarcoma.

Radiological Reasoning: Bone Marrow Changes on MRI

OBJECTIVE Differentiating neoplastic from nonneoplastic bone marrow changes on imaging can be challenging. MRI provides the most helpful information when using T1-weighted and opposed-phase (chemical shift) sequences. We discuss the MRI assessment of bone marrow in the context of a complex clinical case. CONCLUSION The case shows a false-positive result of opposed-phase imaging of bone marrow, which was a postinflammatory cause resulting in marrow fibrosis that mimicked neoplastic marrow infiltration and necessitated biopsy for definitive diagnosis.

The Vascular Groove Sign: A New CT Finding Associated With Osteoid Osteomas

OBJECTIVE We have observed that osteoid osteomas are frequently surrounded by thin curvilinear or serpiginous low-density grooves in the surrounding bone on CT examinations. We believe that these grooves represent prominent enlarged feeding arterioles, corresponding to recently published histologic findings. This study was performed to assess the sensitivity and specificity of this vascular groove sign for differentiating osteoid osteomas from other radiolucent bone lesions. MATERIALS AND METHODS The study group consisted of 42 patients with pathologically proven osteoid osteomas. The control group included 29 patients with radiolucent bone lesions other than osteoid osteomas. Two readers scored CT examinations of these lesions for the presence of the vascular groove sign, defined as one or more radiolucent linear or serpiginous grooves extending from the periosteal surface of bone down to the radiolucent tumor. Sensitivity and specificity values were calculated for each reader. Positive and negative predictive values, p values, and interobserver agreement values were calculated. RESULTS The sensitivity of the vascular groove sign for detection of osteoid osteoma was 73.8% for reader 1 and 76.2% for reader 2, specificity was 96.6% for reader 1 and 89.7% for reader 2, positive predictive value was 96.9% for reader 1 and 91.4% for reader 2, and negative predictive value was 71.8% for reader 1 and 72.2% for reader 2. The p value was less than 0.0001 for both readers. The interobserver agreement was very good, with a kappa value of 0.85. CONCLUSION The vascular groove sign is a moderately sensitive but highly specific sign for distinguishing osteoid osteomas from other radiolucent bone tumors on CT.