Susan S. Paine

Serial FDG-PET studies in the prediction of survival in patients with primary brain tumors

Objective This study examines the changes in tumor [18F]fluoro-2-deoxyglucose (FDG) uptake on serial FDG-PET studies and the ability of serial FDG-PET studies to predict survival in patients with treated and untreated primary brain tumors. Materials and Methods The study population included 20 patients with primary brain tumors. Changes in FDG uptake over time were visually assessed and correlated with clinical course and survival. Results Although little change in FDG uptake was noted for individual patients, high average FDG uptake (greater than or equal to gray matter) on serial studies was associated with shorter survival. Patients with persistently low FDG uptake (less than gray matter) survived significantly longer than patients with persistently high FDG uptake (p = 0.007). Conclusion Serial evaluation of metabolic activity with PET may provide more accurate prognostic information than a single FDG uptake determination in patients with primary brain tumors.

Midgut carcinoid tumors: CT findings and biochemical profiles.

Objective Our goal was to describe the abdominal CT findings in 52 patients with midgut carcinoid tumors and correlate these findings with their biochemical profiles. Materials and Methods Abdominal/pelvic CTs of 52 patients with midgut carcinoid tumors were reviewed retrospectively for the presence of liver metastases, mesenteric and peritoneal disease, bowel changes, lymphadenopathy, and the presence of the primary tumor. Logistic regression models were used to evaluate the association between these findings and the serum and platelet serotonin and urine 5-hydroxyindolacetic acid levels. Results The most common finding was hepatic metastases (34/52). Nonspecific mesenteric soft tissue stranding was present in 26 of 52 and a discrete mesenteric mass was present in 25 of 52. These masses had linear, radiating soft tissue spokes in 16 of 25 and contained calcification in 10 of 25. Retroperitoneal and mesenteric lymphadenopathy was present in 14 of 52 and 11 of 52 cases, respectively. Carcinomatosis was present in 11 of 52. Bowel wall thickening was seen in 9 of 52. Six patients had a small bowel obstruction. Elevated serum serotonin, platelet serotonin, and urine 5-hydroxyindolacetic acid levels were significantly associated with the presence of liver metastases (p = 0.0032, 0.0098, and 0.0450, respectively). Elevated platelet serotonin levels were also significantly associated with the presence of a mesentenc mass (p = 0.0101). Conclusion In our population, the most common findings of a midgut carcinoid tumor are liver metastases, nonspecific mesenteric soft tissue changes, a discrete mesenteric mass with radiating soft tissue spokes, often containing calcification, and lymphadenopathy. As expected, liver metastases correlate strongly with the presence of elevated biochemical levels. A new observation is the correlation of elevated platelet serotonin levels and mesenteric masses. We hypothesize that platelet serotonin may be the factor that stimulates stromal cells to produce mesenteric fibrosis and mass formation.

18‐FLUORODEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY IN CHILDREN AND ADOLESCENTS WITH TRAUMATIC BRAIN INJURY

Twenty‐two previously normal children and adolescents who suffered a severe, non‐penetrating traumatic brain injury had PET during rehabilitation at a median of 1–5 months after the injury. Outcome was assessed at a median of 25 months after brain injury. 16 subjects had CT or MRI within 24 days of PET and 11 subjects had a second PET at the point of outcome (median 28 months after first PET). The PET score (obtained by adding the score of 15 brain regions: normal metabolism = 1; reduced = 0) was significantly associated with the clinical outcome measure. PET earlier than 12 weeks after head trauma correlated with outcome, but later PET did not. PET scores improved significantly between rehabilitation and outcome for the 11 subjects who had two PETs, but improvement was not associated with improvement in clinical condition. PET score did not add to the amount of variance explained in the last regression model for prediction of outcome when the results of contemporaneous CT/MRI and clinical condition were taken into account. The data suggest that routine PET during rehabilitation is no more useful than contemporaneous CT or MRI for prediction of outcome.

Hypochondriasis and Somatization Related to Personality and Attitudes Toward Self

Better definition of the boundary between hypochondriasis and somatization was determined by measuring attitudes to self and personality dimensions associated with these syndromes. In this study, the primary care patients with hypochondriacal responses (HR) on the Illness Attitudes Scales or high somatic concern (HSC) on the Symptom Questionnaire had more negative attitudes to self and more psychological distress than the matched group of primary care control subjects. The HR subjects were different from the non-HR subjects on two of five personality domains on the NEO Personality Inventory (NEO)-Five-Factor Inventory, and the HSC subjects were different from the non-HSC subjects on four of five NEO domains. Analysis of variance demonstrated that somatization explained most of the variance in attitudes, personality, and psychological distress, but hypochondriasis uniquely contributed only to thanatophobia. The authors discuss the boundary between hypochondriasis and somatization and offer a descriptive model of this relationship.

INTERPRETATION VARIABILITY OF 18FDG-POSITRON EMISSION TOMOGRAPHY STUDIES IN DEMENTIA

RATIONALE AND OBJECTIVES Functional imaging studies such as 18F-fluoro-18-labeled-deoxyglucose-positron emission tomography (18FDG-PET) are being used increasingly in the evaluation of patients with dementia. The authors evaluate inter- and intraobserver interpretation agreement in a diverse group of patients with clinically diagnosed dementia and subjective memory complaints, as well as two healthy control subjects. METHODS Ninety-six patients with clinical diagnoses of probable Alzheimers disease (n = 18), possible Alzheimers disease (n = 33), dementia (n = 26), and mild memory impairment (n = 17), as well as two healthy control subjects were studied using 18FDG-PET. Three observers graded all studies for regional 18FDG uptake in the temporal, parietal, and frontal regions bilaterally. The studies also were interpreted for the presence of bilateral temporoparietal hypometabolism, which typically is present in Alzheimers disease. The kappa statistic was used to determine intra- and interobserver agreement for regional 18FDG uptake and bilateral temporoparietal hypometabolism. RESULTS There was excellent intraobserver (kappa = .56, P < 0.0005) and interobserver (kappa = .51, P < 0.0005) interpretation agreement for bilateral temporoparietal hypometabolism. There also was excellent intraobserver (kappa = .61, P < 0.000) and interobserver (kappa = .55, P < 0.000) interpretation agreement of regional 18FDG uptake. Interobserver agreement was extremely high in those patients who were considered clinically to have possible (kappa = .42, P < 0.001) or probable (kappa = .42, P < 0.01) Alzheimers disease. CONCLUSIONS Results confirm that bilateral temporoparietal hypometabolism is the metabolic abnormality associated with the diagnosis of probable Alzheimers disease. Furthermore, intra- and interobserver agreement of visual interpretation of 18FDG-PET images indicates that 18FDG-PET is acceptable as an imaging technique in the clinical evaluation of the dementia patient.

The diagnostic accuracy/efficacy of MRI in differentiating hepatic hemangiomas from metastatic colorectal/breast carcinoma : A multiple reader ROC analysis using a jackknife technique

PURPOSE Our purpose was to determine the diagnostic accuracy efficacy of a simple MR technique in differentiating hepatic hemangiomas from colorectal or breast metastases using a multiple reader method. METHOD Thirty-seven cases with confirmed hepatic hemangiomas and 115 with confirmed hepatic metastases (colon primary, n = 86; breast primary, n = 29) evaluated with MRI at 1.5 T were retrospectively collected. A single lesion in a single slice from each patient was randomly selected; the images were masked and then were interpreted in random order by five separate readers blinded to the diagnosis using a five point diagnostic scale (from definite hemangioma to definite metastasis). Morphologic characteristics of lesion margin, signal intensity relative to other structures, and internal architecture (homogeneous versus heterogeneous) were also assessed independently of the five point diagnostic scale. Three of the readers had > 8 years of experience, while the other two had 1 and 3 years. The diagnostic scale results were subjected to receiver operating characteristic (ROC) analysis using a jackknife method. kappa-Statistics were applied to assess interreader agreement in the morphologic characteristics. A logistic regression model was used to determine which characteristics predicted pathology and reader diagnosis. RESULTS ROC analysis showed the average area under the curve over all readers was (0.91 (0.89-0.93 95% confidence interval) (p < 0.0001). An analysis of variance showed no significant difference between the areas under the curves of each reader (p = 0.6433). When the definite and probable categories for hemangioma and metastasis were combined, the sensitivity/specificity for the diagnosis of hemangioma ranged from 57 to 73%/91 to 97%. The positive/negative predictive value ranged from 72 to 84%/87 to 91%. For the morphologic assessment, there was significant agreement between the readers (p < 0.0001-0.0037). A sharp margin and lesion signal equal to or greater than CSF predicted the presence of a hemangioma (p = 0.0148 and p < 0.0001, respectively). A sharp margin, lesion signal equal to or greater than CSF, and a homogeneous internal architecture all predicted the reader diagnosis of definitely or probably hemangioma. CONCLUSION For multiple readers, T2-weighted SE MRI alone is a very specific method for distinguishing hemangiomas from metastatic colon or breast carcinoma. Morphologic characteristics of a sharp margin and a high signal predict the presence of a hemangioma. Last, reader experience does not appear to have a significant effect on the specificity.

Bilateral lower extremity evaluation of deep venous thrombosis with color flow and compression sonography

Recognition of the accuracy of CUS for diagnosis of DVT has led to increased requests for bilateral lower extremity CUS studies. Compared to unilateral lower limb CUS studies, these examinations are often requested when the clinical suspicion of DVT is less strong. We undertook a 15 month prospective study of bilateral lower extremity CUS examinations to determine the diagnostic yield of positive studies and any correlation with clinical parameters. Eighty‐six patients were studied; six patients (7%) had studies positive for acute DVT, and 78 patients (91%) had negative studies. Positive studies did not correlate with clinical parameters except erythema. Concurrently, 23% of unilateral lower limb sonographic studies were positive. Bilateral lower limb CUS is a low yield investigation, which may be indicated in view of the morbidity and mortality associated with DVT and pulmonary embolism.

Detection of focal hepatic masses: STIR MR vs. CT during arterial portography.

Objective Our goal was to compare short τ inversion recovery MRI (STIR) to CT during arterial portography (CTAP) in the detection of hepatic lesions. Materials and Methods Over a 24 month period, 40 patients evaluated for possible hepatic resection underwent T1, T2, and STIR MRI and CTAP. These studies were randomly ordered and interpreted by two independent readers. The total number of lesions and number of lesions within each hepatic segment were analyzed using McNemars test. Results Readers 1 and 2 detected 95 and 91 lesions by CTAP and 78 and 83 by STIR, respectively, which was not significantly different (p = 0.1, reader 1; p = 0.4, reader 2). For both readers CTAP and STIR MRI detected more lesions than either T2 or TI MRI (p < 0.01). In the medial segment, readers 1 and 2 detected 18 and 17 lesions by CTAP and 7 and 9 by STIR, respectively (p = 0.01, reader 1; p = 0.035, reader 2). Conclusion Short τ inversion recovery MRI and CTAP are similar in total lesion detection except in the medial segment where lesions were more frequently identified by CTAP than STIR MRI.

Liver MR imaging: comparison of respiratory triggered fast spin echo with T2-weighted spin-echo and inversion recovery

AbstractBackground: The purpose of this study was to compare a fast spin-echo sequence combined with a respiratory triggering device (R. trig. FSE) with conventional T2-weighted spin-echo (CSE) and inversion recovery (STIR) sequences for the detection of focal hepatic lesions. Methods: We performed a prospective study of 33 consecutive patients with known or suspected hepatic tumors. All patients underwent R. trig. FSE, CSE, and STIR imaging at 1.5 T. Acquisition times were 10.7 min for the CSE sequence and ranged from 12 to 15 min for STIR and from 5 to 7 min for R. trig FSE. For each sequence, live-spleen contrast-to-noise ratio (CNR) and liver-lesion CNR were determined quantitatively. Image artifact and sharpness were graded by using a four-point scale on each sequence by two independent readers. Both readers also independently identified hepatic lesions (up to a maximum of eight per patient). For patients with focal lesions, the total number of lesions detected (on each sequence) and the minimum size of detected lesions were also determined by each reader. Results: No significant difference was detected between R. trig. FSE and CSE or STIR in either liver-spleen CNR or liver-lesion CNR. R. trig. FSE images were equivalent to CSE and superior to STIR in sharpness (p <0.01) and presence of artifact (p<0.01). R. trig. FSE detected a higher number of lesions (reader 1: n=92, reader 2: n=86) than CSE (reader 1: n=70, reader 2: n=69) and a significantly higher number than STIR (reader 1: n=71, reader 2: n=76). Lesion structure was significantly better defined with R. trig. FSE than with STIR (p<0.01) and CSE (p<0.05). Conclusions: Compared with CSE and STIR, R. trig. FSE produces hepatic images of comparable resolution and detects an increased number of focal hepatic lesions in a shorter period of time.

Physician experience with viewing digital radiographs in an intensive care unit environment

After several years of continuous operation, the utility of digital viewing stations as assessed by bedside clinicians has been investigated through the distribution of questionnaires to past and present users. The results of the questionnaire have indicated that the bedside physicians prefer using the workstations over handling film. For evaluation of line placements, chest tubes, and pleural effusions, the physicians prefer softcopy display over hardcopy. However, for analysis of air space disease and diagnosis of pneumothorax, images displayed on the workstation were not believed to be as useful as standard hardcopy.