What's in a name? Eponyms in head and neck imaging.

Head and neck (H&N) eponyms serve to honour physicians who have made important contributions. Compared with more descriptive diagnostic names, eponyms can sometimes be confusing, especially to the novice. Adding to the confusion, eponyms are sometimes applied incorrectly. Nevertheless, their use remains common in the medical literature and clinical practice. Familiarity with H&N eponyms is important for accurate communication with radiology colleagues and clinicians. Some eponyms describe potentially fatal infections and their urgency should be appreciated. Other eponyms, such as those for inner ear congenital anomalies, are probably best avoided as they can be used imprecisely and cause confusion. This review summarizes the clinical and imaging findings of some common and important H&N eponyms under the following categories of disease: (1) neck infections, (2) diseases in the temporal bone, (3) orbital diseases, and (4) sinus disease.

Dynamic CT perfusion imaging in subarachnoid hemorrhage-related vasospasm.

BACKGROUND AND PURPOSE: Nimodipine is a therapy that reduces morbidity and mortality in patients with subarachnoid hemorrhage (SAH), though the mechanisms by which it does so are not well understood. In a rabbit model of SAH, we studied the effects of nimodipine by using functional CT imaging. We hypothesized that the nimodipine treatment group would have (1) increased mean basilar artery diameter, (2) less diminished cerebral blood flow (CBF) following vasospasm, and (3) better neurologic outcomes. METHODS: SAH was induced in 26 New Zealand White rabbits randomized to 2 groups: treated (nimodipine) or control (no treatment). CT perfusion and CT angiography were used to measure CBF and basilar artery diameter at baseline, 10, 30, and 60 minutes after SAH, and on days 3, 5, 7, 9, and 16. Neurologic assessments were performed on each day of scanning. RESULTS: Basilar artery diameter in the treated group was greater than in the control group post-SAH (P < .05). When vasospasm was >15%, CBF in the nimodipine group was significantly greater than in the control group in the brain stem, cerebellum, parieto-occipital cerebrum, and deep gray matter (P < .05). Neurologic scores in the nimodipine group were significantly better than in the control group on days 5 and 9 (P < .05). CONCLUSION: Animals treated with nimodipine showed (1) increased mean basilar artery diameter, (2) improved neurologic outcome, and (3) increased mean CBF despite no significant difference in the incidence and severity of delayed vasospasm. These data provide a basis for future studies comparing the efficacy of new treatments for SAH to that of nimodipine.

Comparative overview of brain perfusion imaging techniques.

Numerous imaging techniques have been developed and applied to evaluate brain hemodynamics. Among these are: Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), Xenon-enhanced Computed Tomography (XeCT), Dynamic Perfusion-computed Tomography (PCT), Magnetic Resonance Imaging Dynamic Susceptibility Contrast (DSC), Arterial Spin-Labeling (ASL), and Doppler Ultrasound. These techniques give similar information about brain hemodynamics in the form of parameters such as cerebral blood flow (CBF) or volume (CBV). All of them are used to characterize the same types of pathological conditions. However, each technique has its own advantages and drawbacks. This article addresses the main imaging techniques dedicated to brain hemodynamics. It represents a comparative overview, established by consensus among specialists of the various techniques. For clinicians, this paper should offers a clearer picture of the pros and cons of currently available brain perfusion imaging techniques, and assist them in choosing the proper method in every specific clinical setting.

Perception without awareness: perspectives from cognitive psychology.

Four basic approaches that have been used to demonstrate perception without awareness are described. Each approach reflects one of two types of experimental logic and one of two possible methods for controlling awareness. The experimental logic has been either to demonstrate a dissociation between a measure of perception with awareness and a measure that is sensitive to perception without awareness or to demonstrate a qualitative difference between the consequences of perception with and without awareness. Awareness has been controlled either by manipulating the stimulus conditions or by instructing observers on how to distribute their attention. The experimental findings based on all four approaches lead to the same conclusion; namely, stimuli are perceived even when observers are unaware of the stimuli. This conclusion is supported by results of studies in which awareness has been assessed with either objective measures of forced-choice discriminations or measures based on verbalizations of subjective conscious experiences. Given this solid empirical support for the concept of perception without awareness, a direction for future research studies is to assess the functions of information perceived without awareness in determining what is perceived with awareness. The available evidence suggests that information perceived without awareness both biases what stimuli are perceived with awareness and influences how stimuli perceived with awareness are consciously experienced.

An unusual variant of the fronto-orbital artery.

A patient with a rare variation of the fronto-orbital artery is presented. In this case, the fronto-orbital artery arises from the A1 segment of the contralateral anterior cerebral artery. The angiographic findings in this case are illustrated and discussed. The importance of recognizing this variant is related to the planning of surgery or endovascular therapy in the anterior cerebral artery region.

Retropharyngeal effusion in acute calcific prevertebral tendinitis: diagnosis with CT and MR imaging.

Three patients with the diagnosis of acute calcific prevertebral tendinitis underwent CT or a combination of CT and MR imaging, which showed previously described findings of calcifications within the tendons of the longus colli muscles. In addition, however, we detected a retropharyngeal effusion in all three patients. The importance of this finding lies in the need to differentiate this effusion from retropharyngeal infection.

Diffusion-weighted MR imaging of the normal human spinal cord in vivo.

BACKGROUND AND PURPOSE: Diffusion-weighted imaging is a robust technique for evaluation of a variety of neurologic diseases affecting the brain, and might also have applications in the spinal cord. The purpose of this study was to determine the feasibility of obtaining in vivo diffusion-weighted images of the human spinal cord, to calculate normal apparent diffusion coefficient (ADC) values, and to assess cord anisotropy. METHODS: Fifteen healthy volunteers were imaged using a multi-shot, navigator-corrected, spin-echo, echo-planar pulse sequence. Axial images of the cervical spinal cord were obtained with diffusion gradients applied along three orthogonal axes (6 b values each), and ADC values were calculated for white and gray matter. RESULTS: With the diffusion gradients perpendicular to the orientation of the white matter tracts, spinal cord white matter was hyperintense to central gray matter at all b values. This was also the case at low b values with the diffusion gradients parallel to the white matter tracts; however, at higher b values, the relative signal intensity of gray and white matter reversed. With the diffusion gradients perpendicular to spinal cord, mean ADC values ranged from 0.40 to 0.57 x 10(-3) mm2/s for white and gray matter. With the diffusion gradients parallel to the white matter tracts, calculated ADC values were significantly higher. There was a statistically significant difference between the ADCs of white versus gray matter with all three gradient directions. Strong diffusional anisotropy was observed in spinal cord white matter. CONCLUSION: Small field-of-view diffusion-weighted images of the human spinal cord can be acquired in vivo with reasonable scan times. Diffusion within spinal cord white matter is highly anisotropic.

Does unattended information facilitate change detection?

Changes between alternating visual displays are difficult to detect when the successive presentations of the displays are separated by a brief temporal interval. To assess whether unattended changes attract attention, observers searched for the location of a change involving either a large or a small number of features, in pairs of displays consisting of 4, 7, 10, 13, or 16 letters (Experiment 1) or digits (Experiments 2 and 3). Each display in a pair of displays was presented for 200 ms, and either a blank screen (Experiments 1 and 2) or a screen of equal luminance to the letters and digits (Experiment 3) was presented for 80 ms between the alternating displays. In all experiments, the search function for locating the larger change was shallower than the search function for locating the smaller change. These results indicate that unattended changes play a functional role in guiding focal attention.

The folly of effort: ironic effects in the mental control of pain.

During exposure to pain, participants who were engaged in hypnotic analgesia or stress inoculation provided pain reports every 5 s and 45 s, respectively. It was found that the frequency of pain reporting had a significant effect on participants' level of experienced pain. This finding is discussed in the context of important methodological implications for laboratory investigations of analgesia. Furthermore, preliminary evidence was obtained suggesting that high hypnotizables in hypnotic analgesia remained relatively undisrupted by frequent pain reporting. Based on Wegner's (1994) ironic process theory, it is argued that this pattern of results is inconsistent with theories of hypnosis that propose that hypnotized individuals intentionally engender responses while remaining unaware of their sustained, deliberate effort. The obtained pattern of results was, however, predicted from the dissociated control model of hypnosis (Bowers, 1990, 1992).

High variability in radiologists' reporting practices for incidental thyroid nodules detected on CT and MRI.

BACKGROUND AND PURPOSE: There are no guidelines for reporting incidental thyroid nodules seen on CT and MR imaging. We evaluated radiologists' current reporting practices for incidental thyroid nodules detected on these imaging modalities. MATERIALS AND METHODS: Radiologists were surveyed regarding their reporting practices by using 14 scenarios of incidental thyroid nodules differing in size, patient demographics, and clinical history. Scenarios were evaluated for the following: 1) radiologists' most commonly selected response, and 2) the proportion of radiologists selecting that response (degree of agreement). These measures were used to determine how the patient scenario and characteristics of the radiologists affected variability in practice. RESULTS: One hundred fifty-three radiologists participated. In 8/14 scenarios, the most common response was to "recommend sonography." For the other scenarios, the most common response was to "report in only body of report." The overall mean agreement for the 14 scenarios was 53%, and agreement ranged from 36% to 75%. Smaller nodules had lower agreement: 43%-51% for 8-mm nodules compared with 64%-75% for 15-mm nodules. Agreement was poorest for the 10-mm nodule in a 60-year-old woman (36%) and for scenarios with additional history of lung cancer (39%) and multiple nodules (36%). There was no significant difference in reporting practices and agreement when radiologists were categorized by years of practice, practice type, and subspecialty (P > .55). CONCLUSIONS: The reporting practice for incidental thyroid nodules on CT or MR imaging is highly variable among radiologists, especially for patients with smaller nodules (≤10 mm) and patients with multiple nodules and a history of cancer. This variability highlights the need for practice guidelines.

An exponential growth in incidence of thyroid cancer: trends and impact of CT imaging.

BACKGROUND AND PURPOSE: Workup of incidental thyroid nodules detected on CT imaging could be contributing to the increased diagnosis of small thyroid cancers. The purpose of this study was to evaluate recent trends in the incidence of thyroid cancer, and to determine the relationship between annual CT imaging volume and rate of thyroid cancer diagnosis. MATERIALS AND METHODS: This retrospective cohort study used data bases for thyroid cancer and CT imaging volume. Thyroid cancer data from 1983-2009 were obtained from the Surveillance, Epidemiology, and End Results data base. National Council of Radiation Protection and Measurements Report No. 160 provided data on hospital and nonhospital CT imaging volume for 1993-2006. Trends in thyroid cancer were modeled for overall incidence on the basis of patient age, tumor histologic features, and tumor size and stage. Linear regression analysis was performed to evaluate the strength of the relationship between annual CT scan volume and the incidence of thyroid cancer by tumor size and histologic type. RESULTS: In 2009, the incidence of thyroid cancer was 14 per 100,000, which represented a 1.9-fold increase compared with 2000. The growth in incidence was exponential compared with a minimal linear increase in thyroid cancer mortality rate. The subgroup with the greatest change was subcentimeter papillary carcinoma, with doubling in incidence approximately every 6.2 years. The linear relationship between annual CT scan volume and the incidence of subcentimeter papillary carcinoma was very strong (R(2) = 0.98; P < .0001). CONCLUSIONS: The incidence of subcentimeter papillary carcinoma is growing at an exponential rate without significant change in mortality rate. The strong linear relationship between new cases of subcentimeter papillary carcinomas and the number of CT scans per year suggests that an increase in CT scans may increase the detection of incidental thyroid cancers.

Physician self-referral and imaging use appropriateness: negative cervical spine MRI frequency as an assessment metric.

BACKGROUND AND PURPOSE: Imaging self-referral is increasingly cited as a contributor to diagnostic imaging overuse. The purpose of this study was to determine whether ownership of MR imaging equipment by ordering physicians influences the frequency of negative cervical spine MR imaging findings. MATERIALS AND METHODS: A retrospective review was performed of 500 consecutive cervical spine MRIs ordered by 2 separate referring-physician groups serving the same geographic community. The first group owned the scanners used and received technical fees for their use, while the second group did not. Final reports were reviewed, and for each group, the percentage of negative study findings and the frequency of abnormalities were calculated. The number of concomitant shoulder MRIs was recorded. RESULTS: Five hundred MRIs meeting inclusion criteria were reviewed (250 with financial interest, 250 with no financial interest). Three hundred fifty-two had negative findings (190 with financial interest, 162 with no financial interest); there were 17.3% more scans with negative findings in the financial interest group (P = .006). Among scans with positive findings, there was no significant difference in the mean number of lesions per scan, controlled for age (1.90 with financial interest, 2.19 with no financial interest; P = .23). Patients in the financial interest group were more likely to undergo concomitant shoulder MR imaging (24 with financial interest, 11 with no financial interest; P = .02). CONCLUSIONS: Cervical spine MRIs referred by physicians with a financial interest in the imaging equipment used were significantly more likely to have negative findings. There was otherwise a highly similar distribution and severity of disease between the 2 patient samples. Patients in the financial interest group were more likely to undergo concomitant shoulder MR imaging.

Recurrent laryngopyocele: CT-guided hookwire localization for re-excision surgery.

Laryngopyocele recurrence after initial surgical resection is a very rare occurrence. We present a case of recurrent laryngopyocele in which CT fluoroscopy-guided hookwire placement was used to facilitate resection. In this article, we illustrate the imaging findings of laryngopyocele, review the approach to management, and describe the CT fluoroscopy-guided hookwire placement procedure.

CT-guided cervical transforaminal steroid injections: where should the needle tip be located?

BACKGROUND AND PURPOSE: The aim of CT-guided CTSI is to inject medication into the foraminal region where the nerve root is inflamed. The optimal location for needle placement and therapeutic delivery, however, remain uncertain. The purpose of this study was to investigate how needle positioning and angle of approach impact the transforaminal distribution of injectate. MATERIALS AND METHODS: We retrospectively reviewed fluoroscopic images from 90 CT-guided CTSI procedures for needle-tip location, needle angle, and contrast distribution. Needle-tip position was categorized as either foraminal zone, junctional, or extraforaminal. Distribution of contrast injected immediately before steroid administration was categorized as central epidural, intraforaminal, or extraforaminal in location. Needle-tip location and angle were correlated with contrast distribution. RESULTS: The needle tip was most commonly placed in the junctional position (36 cases, 40%), followed by foraminal (30 cases, 33%) and extraforaminal (24 cases, 27%) locations. Intraforaminal contrast distribution was highest when the needle location was foraminal (30/30, 100%) or junctional (35/36, 97%), compared with extraforaminal (7/24, 29%) (P value <.0001). There was no relationship between needle angle and contrast distribution. CONCLUSIONS: Needle-tip location at the outer edge of the neural foramen (junctional location) correlated well with intraforaminal distribution of contrast for CT-guided CTSI and compared favorably with injectate distribution following foraminal zone needle positioning. Junctional needle positioning may be preferred over the foraminal zone by some proceduralists. Extraforaminal needle positioning resulted in less favorable contrast distribution, which may significantly diminish the therapeutic efficacy of CTSI.

Incidental thyroid nodules on CT: evaluation of 2 risk-categorization methods for work-up of nodules.

BACKGROUND AND PURPOSE: Thyroid nodules are common incidental findings on CT, but there are no clear guidelines regarding their further diagnostic work-up. This study compares the performance of 2 risk-categorization methods of selecting CT-detected incidental thyroid nodules for work-up. MATERIALS AND METHODS: The 2 categorization methods were method A, based on nodule size ≥10 mm, and method B, a 3-tiered system based on aggressive imaging features, patient age younger than 35 years or nodule size of ≥15 mm. In part 1, the 2 categorization methods were applied to thyroid cancers in the SEER data base of the National Cancer Institute to compare the cancer capture rates and survival. In part two, 755 CT neck scans at our institution were retrospectively reviewed for the presence of ITNs of ≥5 mm, and the same 2 categorization methods were applied to the CT cases to compare the number of patients who would theoretically meet the criteria for work-up. Comparisons of proportions of subjects captured under methods A and B were made by using the McNemar test. RESULTS: For 84,720 subjects in the SEER data base, methods A and B each captured 74% (62,708/84,720 and 62,586/84,720, respectively) of malignancies. SEER subjects who would not have met the criteria for further work-up by both methods had equally excellent 10-year cause-specific and relative survival of >99%. For part 2, the prevalence of ITNs of ≥5 mm at our institution was 133/755 (18%). The number of ITNs that would be recommended for work-up by method A was 57/133 (43%) compared with 31/133 (23%) for method B (P < .0005). CONCLUSIONS: Compared with using a 10-mm cutoff, the 3-tiered risk-stratification method identified fewer ITNs for work-up but captured the same proportion of cancers in a national data base and showed no difference in missing high-mortality cancers.

Parathyroid lesions: characterization with dual-phase arterial and venous enhanced CT of the neck.

This clinical report describes the enhancement characteristics of hypersecreting parathyroid lesions on dual-phase neck CT. We retrospectively analyzed the enhancement characteristics of 5 pathologically confirmed PTH-secreting lesions on dual-phase CT examinations. Attenuation values were measured for PTH-secreting lesions, vascular structures (CCA and IJV), and soft tissue structures (thyroid gland, jugulodigastric lymph node, and submandibular gland). From the attenuation values, "relative enhancement washout percentage" and "tissue-vascular ratio" were calculated and compared. All lesions decreased in attenuation from arterial to venous phase, while the mean attenuation values of other soft tissue structures increased. A high relative enhancement washout percentage was correlated with parathyroid lesions (P < .006). The tissue-CCA ratio and tissue-IJV ratio for PTH-secreting lesions in the arterial phase were statistically significantly higher compared with soft tissue structures (P < .05). If these results are validated in future larger studies, noncontrast and delayed venous phases of 4D-CT could be eliminated to markedly reduce radiation exposure.

CT-guided lumbar nerve root injections: are we using the correct radiation dose settings?

BACKGROUND AND PURPOSE: Selecting a lower tube current for CT fluoroscopic spine injections is a method of radiation dose reduction. Ideally tube current should be tailored to the patient's body habitus, but a greater influence on tube current may be the proceduralist's personal preference. The purpose of this study was to compare tube current and fluoroscopy time of different proceduralists for lumbar spine CT-guided selective nerve root blocks, and to correlate image quality to patient diameter and tube current. MATERIALS AND METHODS: Eighty CT-guided SNRBs performed by 4 proceduralists were retrospectively reviewed for tube current and fluoroscopy time. Patient body habitus was evaluated by measuring anteroposterior diameters on scout images. Image quality was evaluated objectively and subjectively: noise was measured in the psoas muscle and images were graded on a 3-point scale. RESULTS: The mean tube current was 59 ± 20 mA and mean fluoroscopy time was 10.4 ± 7.5 seconds. The mean tube current between proceduralists differed by almost 2-fold, and there was greater than 2-fold difference in mean fluoroscopy time (P < .0001 and .01, respectively). Mean AP body size was 27 ± 5 cm. When categoric data of tube current and AP diameter were analyzed, only AP diameter was a statistically significant variable influencing image noise (P = .009). Twenty of 23 patients with AP diameter ≤30 cm had adequate to excellent image quality, even with lower tube current of ≤40 mA. CONCLUSIONS: Wide variability in tube current selection between proceduralists calls for a more objective method of selecting tube current to minimize radiation dose. Body size, measured by AP diameter, had the greatest influence on image quality. This could be used to identify patients for lower tube current selection.

CT-guided hookwire placement: a technical innovation for preoperative localization of nonpalpable cervical lymph nodes.

The aim is to describe the technique of preoperative CT-guided hookwire localization of small, but suspicious, cervical lymph nodes. We present 3 patients who underwent the procedure for nonpalpable cervical nodes detected on PET/CT prior to complete surgical resection of the nodes. The details of the radiological procedure, surgical outcomes, and pathologic results are described. The mean intervention time for preoperative hookwire localization was 9 minutes (range 7-14 minutes). There were no complications. All surgeons felt that the lengths of the surgical skin incision and operative times were reduced because of localization. The pathologic diagnoses were 2 benign nodes and 1 case of metastatic ovarian carcinoma. In conclusion, preoperative CT-guided hookwire localization is a useful technique for guiding surgical excision, especially when cervical nodes are small and deep in location.

Bilateral retropharyngeal parathyroid hyperplasia detected with 4D multidetector row CT.

We present a case of bilateral retropharyngeal parathyroid hyperplasia detected with 4D-CT in a patient with persistent primary hyperparathyroidism and failed neck exploration. We discuss the embryologic basis of ectopic retropharyngeal parathyroid adenomas and hyperplasia and the utility of 4D-CT in their localization for surgical planning.

Does diffusion-weighted imaging represent the ischemic core? An evidence-based systematic review.

BACKGROUND AND PURPOSE: Diffusion-weighted(DWI) hyperintensity is hypothesized to represent irreversibly infarcted tissue (ischemic core) in the setting of acute stroke [corrected]. Measurement of the ischemic core has implications for both prognosis and therapy. We wished to assess the level of evidence in the literature supporting this hypothesis. MATERIALS AND METHODS: We performed a systematic review of the literature relating to tissue outcomes of DWI hyperintense stroke lesions in humans. The methodologic rigor of studies was evaluated by using criteria set out by the Oxford Centre for Evidence-Based Medicine. Data from individual studies were also analyzed to determine the prevalence of patients demonstrating lesion progression, no change, or lesion regression compared with follow-up imaging. RESULTS: Limited numbers of highly methodologically rigorous studies (Oxford levels 1 and 2) were available. There was great variability in observed rates of DWI lesion reversal (0%-83%), with a surprisingly high mean rate of DWI lesion reversal (24% of pooled patients). Many studies did not include sufficient data to determine the precise prevalence of DWI lesion growth or reversal. CONCLUSIONS: The available tissue-outcome evidence supporting the hypothesis that DWI is a surrogate marker for ischemic core in humans is troublingly inconsistent and merits an overall grade D based on the criteria set out by the Oxford Centre for Evidence-Based Medicine.