William K. Erly

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.

Elevated androgen, brain development and language/learning disabilities in children with congenital adrenal hyperplasia

Individuals with congenital adrenal hyperplasia (CAH) provide a test population for the theory that elevated testosterone levels alter prenatal brain development and increase the risk of learning disabilities. Eleven subjects with CAH, five of their non‐CAH siblings and 16 matched control subjects participated in two studies. The first study documented hand preference, verbal skills and non‐verbal skills. A higher prevalence of language/learning disability was found in both the CAH subjects and their families than in the control subjects. The second study examined the prevalence of atypical perisylvian asymmetries on MRI scans. These revealed an atypical pattern of asymmetry (R=L or R>L) in the majority of the subjects with CAH and in all of their siblings. One subject with CAH also showed evidence of a neuromigratory disturbance in the posterior left hemisphere. Of the control subjects, only one showed an atypical pattern of asymmetry and none showed evidence of a neuromigratory disorder. The findings indicate that an elevated familial rate for language‐based learning disabilities and altered brain asymmetries co‐occur in families with the gene for CAH.

Location, size, and distribution of mediastinal lymph node enlargement in chronic congestive heart failure.

Purpose The purpose of this study is to identify the prevalence, location, and size of enlarged mediastinal lymph nodes in patients with chronic congestive heart failure and to correlate the presence of lymph node enlargement with cardiac ejection fraction. Methods Sixty-six consecutive, retrospectively identified patients underwent computer tomography (CT) imaging of the thorax as part of a routine work-up prior to cardiac transplantation from 1993 to 1996. CT images of 44 of these patients were independently examined by 3 radiologists for evidence of pulmonary edema, pleural effusions, and the presence, size, and location of lymph nodes >1 cm in short axis. Multigated acquisition (MUGA) scans were available for cardiac ejection fraction assessment in 38 of the 44 patients. Results Twenty-nine (66%) patients had at least 1 mediastinal lymph node >1 cm. The mean ejection fraction was significantly less for patients with lymph node enlargement when compared with patients without lymph node enlargement (20% versus 35%; P < 0.01). Adenopathy was observed in 81% of patients with a calculated ejection fraction of <35%. No patient with an ejection fraction of >35% had lymph node enlargement. There was no correlation between pulmonary edema and the frequency of lymph node appearance. Sixty-three percent of the enlarged nodes were pretracheal, with a mean short axis diameter for all the enlarged nodes of 1.3 cm. Conclusions Enlarged mediastinal lymph nodes were observed in 81% of patients with a calculated ejection fraction of <35%, most commonly in the pretracheal group. The presence of the lymph nodes did not correlate with CT evidence of pulmonary edema.

Academic radiology and doctor discontent: the good news and the bad news.

“Many American doctors are unhappy with the quality of their professional lives” (1). Physicians in all specialties are frustrated by outside forces that interfere with their ability to deliver ideal medical care. Managed care and other forces have decreased their income, and, perhaps because of these forces, disability claims among physicians have escalated (1). There are increased workloads and falling levels of reimbursement coupled with intrusive paperwork and increasing pressures from managed care organizations, licensing agencies, and government entities. The malpractice environment continues to be unpleasant for physicians. Academic physicians are not immune from these stresses. The academic physician is caught between the demands of the marketplace and the demands of providing quality teaching and research. Recent surveys have shown that the workload per radiologist has increased substantially in the past decade (2,3). Private, nonacademic, non-multispecialty practice radiologists perform an average of 12,300 procedures per year (3). Academic radiologists perform an average of 8,000 procedures per year. The average workload for all radiologists has increased 13% between 1991–1992 and 1995–1996 (3). Academic radiologists average less time away from work than full-time nonacademic radiologists in group practice (2). Academic radiologists have, on average, less vacation time and less sick time, but they and nonacademic radiologists have a similar number of days away from work for continuing medical education and professional meetings (2,3). While academic radiologists have a smaller average workload than other radiologists, their workweek is as long as, if not longer than, that of other radiologists. The American College of Radiology (ACR) 1995 survey of radiologists showed that full-time posttraining radiologists reported working, on average, 50 hours per week and 5.l days per week, while academic radiologists reported working, on average, 53 hours per week and 5.3 days per week (2). The perception of radiologists in our own university department and that of our colleagues in other academic radiology departments is that conditions have deteriorated considerably in the past decade. Many believe that academic time is disappearing, salaries are decreasing, and clinical workloads are increasing. To gauge the accuracy of these perceptions, we sent a simple one-page questionnaire to all members of the Association of University Radiologists in which we asked about the quality of their academic lives. We informally looked at such issues as clinical workloads, the amount of academic time, the amount of managed care, and one’s perception of his or her academic productivity today compared with that 5 years ago. We sent out 1,200 surveys and received responses from 521 individuals (43%) at 188 institutions. In this editorial we refer to the survey only in the context of examining our thesis that there is at present a good news/ bad news environment for the academic radiologist. The radiologists in our department are expected to perform clinical work 4 full days per week, and they receive 1 academic day per week free from clinical duties. While we perceive of this as not being conducive for good acaAcad Radiol 2001; 8:509–511

Can MRI signal characteristics of lumbar disk herniations predict disk regression

Purpose: To assess whether or not MRI signal characteristics of lumbar disk herniations can predict subsequent disk regression. Materials and Methods: Medical and radiology records from 1999-2003 were reviewed, and 123 patients who had more than one lumbar MRI during the study interval were identified. Of these, 42 patients had a disk herniation (protrusion, extrusion, or free fragment) identified on their first examination. Six of the 42 patients were not included because of prior lumbar surgery, or inadequate examinations. The remaining 36 patients had a total of 77 examinations to evaluate 44 disk herniations. The herniated disks were evaluated by two CAQ neuroradiologists for size, morphology and a qualitative assessment of the T2 signal. Results: Between the first and last examination, 25 of 44 (57%) herniated disks decreased, 17 (39%) were unchanged, and two increased in size. 9 of 11 (82%) of disk extrusions improved. The mean size of the disks that regressed was significantly larger than those that were unchanged (8.6 mm vs. 6 mm, p =.001). On average, the disks decreased 3.2 mm (37%). Of the disks that decreased in size, 15 (63%) had an area of increased signal on T2-weighted images (T2WI) compared to the parent disk on the initial study. Of the disks that were unchanged, 6 (35%) had increased signal on the T2WIs. Conclusion: 57% of herniated disks in this study group decreased in size over time. Larger herniations and extrusions were more likely to regress than smaller herniations. Disks that regressed were more likely to have high signal on T2WIs than those that were stable.

Acute Stroke Imaging: What Clinicians Need to Know

Advances in technology and software applications have contributed to new imaging modalities and strategies in the evaluation of patients with suspected acute cerebral infarction. Routine computed tomography (CT) and magnetic resonance imaging (MRI) have been the standard studies in stroke imaging, which have been complemented by CT and MR angiography, diffusion-weighted MR imaging, and cerebral perfusion studies, while conventional angiography is typically reserved for intra-arterial therapy. The purpose of this article is to review the variety of imaging studies available in the acute stroke setting, and to discuss the utility of each and the pertinent associated main findings. The appropriateness of which study and when each should be ordered is also discussed. At the conclusion of this article, the reader should have a more clear understanding of the neuroimaging modalities available for acute stroke imaging.

Migrating bullet: A case of a bullet embolism to the pulmonary artery with secondary pulmonary infarction after gunshot wound to the left globe

Bullet embolism is a rare phenomenon following gunshot injuries. We present a case of a 25-year-old male who sustained a gunshot wound to his left globe with the bullet initially lodged in his right transverse sinus. The bullet ultimately embolized to a left lower lobe pulmonary artery resulting in a pulmonary infarct. A discussion of select prior cases, pathophysiology, and management strategies follows.

Abdominal CT for trauma: an adequate screen for lower thoracic and lumbosacral fractures?

Purpose: To assess the utility of routine trauma abdomen and pelvic CT for the detection of lumbosacral spine fractures. Materials and methods: The radiology records of the University of Arizona Medical Center over a 12-month period were reviewed. Fifty-eight patients with suspected blunt abdominal trauma were studied who had both abdominal CT and radiographs of lumbosacral spine. Twenty-two had one or more fractures of the lumbosacral spine. Thirty-six patients who underwent both imaging studies and had no fracture identified by either modality were selected as controls. The images were reviewed independently by three radiologists who were blinded to the CT and plain radiograph findings. Following the blinded review, all discrepancies were reviewed by the interpreting radiologists who then arrived at a consensus interpretation. A fracture was determined to be present if, by consensus of the reviewers, it was seen on either the CT scan or plain radiograph. Results: Thirty-two fractures were identified; 28 (88 %) were identified on CT, 17(53 %) were seen on plain films. Overall routine abdominal CT is significantly more sensitive in the detection of fracture than plain radiographs. No unstable injuries were missed on plain film while one fracture dislocation was missed on CT. Conclusion: Bone images obtained from routine trauma abdomen and pelvic CT are significantly more sensitive than radiographs in the detection of fractures of the lumbosacral spine. However, CT alone may miss significant injuries.

Interval Change in Diffusion and Perfusion MRI Parameters for the Assessment of Pseudoprogression in Cerebral Metastases Treated With Stereotactic Radiation

OBJECTIVE Apparent increases in the size of cerebral metastases after stereotactic radiosurgery (SRS) can be caused by pseudoprogression or true disease progression, which poses a diagnostic challenge at conventional MRI. The purpose of this study was to assess whether interval change in DWI and perfusion MRI parameters can differentiate pseudoprogression from progressive disease after treatment with SRS. MATERIALS AND METHODS Patients with apparent growth of cerebral metastases after SRS treatment who underwent pre- and post-SRS DWI, dynamic susceptibility contrast (DSC)-MRI, and perfusion dynamic contrast-enhanced (DCE)-MRI were retrospectively evaluated. Final assignment of pseudoprogression or progressive disease was determined at 6-month follow-up imaging using the Response Assessment in Neuro-Oncology Brain Metastases criteria. Mean values of apparent diffusion coefficient (ADC), DCE-MRI-derived volume transfer constant (Ktrans), and DSC-MRI-derived relative cerebral blood volume (CBV) from pre- and post-SRS MRI scans were compared between groups using univariate and regression analysis. Fisher exact test was used to compare interval change of imaging biomarkers. RESULTS Of 102 cerebral metastases evaluated, 32 lesions in 29 patients met our inclusion criteria. The mean duration of follow-up was 7.2 months (range, 6-14 months). Twenty-two lesions were determined as pseudoprogression, and 10 lesions were determined as progressive disease using the Response Assessment in Neuro-Oncology Brain Metastases criteria at 6-month follow-up MRI. The interval change pattern of our imaging parameters matched the expected patterns of treatment response for ADC (23/32 lesions; 72%; p = 0.055; odds ratio, 5.1), Ktrans (24/32 lesions; 75%; p = 0.006; odds ratio, 19.2), and relative CBV (27/32 lesions; 84%; p = 0.001; odds ratio, 25.3). CONCLUSION Pseudoprogression can be distinguished from disease progression in cerebral metastases treated with SRS via an interval decrease in relative CBV and Ktrans values.

Evaluation of head CT exams - resident and attending diagnoses

The goal of this study was to evaluate performance of radiology resident in interpretation of head CT exams ordered by emergency room physicians, and to compare their accuracy with the attending radiologists. 1324 consecutive CT head exams ordered by the ER were interpreted by radiology residents. They reported whether the case was normal or abnormal, noted the relevant findings, and reported their decision confidence using a 6-point scale. Attending neuroradiologists subsequently interpreted the exams. The exams were grouped into 3 categories based on correlation of readings: agree, disagree-insignificant, disagree-significant. There was 91% agreement between resident and attending diagnoses, 7% disagree-insignificant and 2% disagree- significant. Disagreements occurred more often on abnormal than normal cases. Disagreements occurred more often with 1st and 2nd year residents than with 3rd and 4th. Resident confidence was highest for 3rd years, followed by 4th, 2nd and 1st. The less confident a resident was in their diagnosis, the more likely a disagreement occurred. Cases in which a resident expresses a low level of confidence should be carefully checked by the attending since these cases were more often associated with a disagreement than those with high confidence.