Leslie E. Quint

Comparison of magnetic resonance imaging and ultrasonography in staging early prostate cancer: Results of a multi-institutional cooperative trial

Abstract Background. In 1987, a cooperative study group consisting of five institutions was formed to determine the relative benefits of magnetic resonance imaging (MRI) and endorectal (transrectal) ultrasonography in evaluating patients with clinically localized prostate cancer (stage Ta or Tb). Methods. Over a period of 15 months, 230 patients were entered into the study and evaluated with identical imaging techniques. We compared imaging results with information obtained at the time of surgery and on pathological analysis. Results. MRI correctly staged 77 percent of cases of advanced disease and 57 percent of cases of localized disease; the corresponding figures for ultrasonography were 66 and 46 percent (P not significant). These figures did not vary significantly between readers; moreover, simultaneous interpretation of MRI and ultrasound scans did not improve accuracy. In terms of detecting and localizing lesions, MRI identified only 60 percent of all malignant tumors measuring more than 5 mm on pat...

Distribution of distant metastases from newly diagnosed non-small cell lung cancer

BACKGROUND The purpose of our study was to determine the incidence and locations of M1 disease at presentation in patients with non-small cell lung cancer to help design appropriate preoperative imaging algorithms. METHODS All patients with non-small cell lung cancer seen between 1991 and 1993 were identified, and records were reviewed. For patients with M1 disease, the sites of distant metastases and the methods of diagnosis were recorded. RESULTS Of 348 patients identified, 276 (79%) had M0 disease and 72 (21%) had M1 disease. In 40 of 72 patients (56%), M1 disease was detected via chest or abdominal computed tomography (CT). Brain, bone, liver, and adrenal glands were the most common sites of metastatic disease, in decreasing order. Brain metastases often occurred as an isolated finding, although isolated liver metastases were uncommon. CONCLUSIONS M1 disease was common at presentation, and was often detectable via chest CT. The incremental yield of abdominal CT over chest CT was very small, and therefore abdominal CT is not an effective method of screening for metastases if chest CT has been performed.

Dose escalation for non-small cell lung cancer using conformal radiation therapy

PURPOSE Improved local control of non-small cell lung cancer (NSCLC) may be possible with an increased dose of radiation. Three-dimensional radiation treatment planning (3D RTP) was used to design a radiation therapy (RT) dose escalation trial, where the dose was determined by (a) the effective volume of normal lung irradiated, and (b) the estimated risk of a complication. Preliminary results of this trial were reviewed. METHODS AND MATERIALS A graph of the iso-normal tissue complication probability (NTCP) levels associated with a dose and effective volume (V(eff)) was derived, using normal tissue parameters derived from the literature. This led to a dose escalation schema, where patients were sorted into 1 of 5 treatment bins, determined by the V(eff) of the best possible treatment plan. The starting doses ranged from 63 to 84 Gy. Each treatment bin was then escalated separately, as in Phase I dose escalation fashion, with Grade > or = 3 radiation pneumonitis defined as dose limiting. To allow for dose escalation, we required patient follow-up to be > or = 6 months for at least three patients. 3D treatment planning was used to irradiate only the radiographically abnormal areas, with 2.1 Gy (corrected for lung inhomogeneity)/day. Clinically uninvolved lymph nodes were not treated prophylactically. RESULTS A total of 48 NSCLC patients have been treated (Stage I/II: 18 patients; Stage III: 28 patients; mediastinal recurrence postsurgery: 2 patients). No radiation pneumonitis has been observed in the 30 patients currently evaluable beyond the 6-month time point. All treatment bins have been escalated at least once. Current doses in the five treatment bins are 69.3, 69.3, 75.6, 84, and 92.4 Gy. None of the 15 evaluable patients in any bin with > or = 30% NTCP experienced clinical radiation pneumonitis, implying that the actual risk is < 20% (beta error rate 5%). Despite the observation of the clinically negative lymph nodes at high risk, there has been no failure in the untreated mediastinum as the sole site of first failure. Three of 10 patients receiving > or = 84 Gy have had biopsy proven residual or locally recurrent disease. CONCLUSION Successful dose escalation in a volume-dependent organ can be performed using this technique. By incorporating the effective volume of irradiated tissue, some patients have been treated to a total dose of radiation over 50% higher than traditional doses. The literature-derived parameters appear to overestimate pneumonitis risk with higher volumes. There has been no obvious negative effect due to exclusion of elective lymph node radiation. When completed, this trial will have determined the maximum tolerable dose of RT as a single agent for NSCLC and the appropriate dose for Phase II investigation.

A Pilot Study of [18F]Fluorodeoxyglucose Positron Emission Tomography Scans During and After Radiation-Based Therapy in Patients With Non–Small-Cell Lung Cancer

PURPOSE To study whether changes of [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) during treatment correlate with post-treatment responses in tumor and normal lung in patients with non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS Patients with stage I to III NSCLC requiring a definitive dose of fractionated radiation therapy (RT) were eligible. FDG-PET/computed tomography scans were acquired before, during, and after RT. Tumor and lung metabolic responses were assessed qualitatively by physicians and quantitatively by normalized peak FDG activity (the ratio of the maximum FDG activity divided by the mean of the aortic arch background). RESULTS The study reached the goal of recruiting 15 patients between February 2004 and August 2005. Of these, 11 patients had partial metabolic response, two patients had complete metabolic response, and two patients had stable disease at approximately 45 Gy during RT. The mean peak tumor FDG activity was 5.2 (95% CI, 4.0 to 6.4), 2.5 (95% CI, 2.0 to 3.0), and 1.7 (95% CI, 1.3 to 2.0) on pre-, during, and post-RT scans, respectively. None of the patients had appreciable changes in the lung during RT. The peak FDG activity of the lung was 0.47 (95% CI, 0.36 to 0.59), 0.52 (95% CI, 0.40 to 0.64), and 1.29 (95% CI, 0.82 to 1.76), on pre-, during-, and post-RT scans, respectively. The qualitative response during RT correlated with the overall response post-RT (P = .03); the peak tumor FDG activity during RT correlated with those 3 months post-RT (R2 = 0.7; P < .001). CONCLUSION This pilot study suggests a significant correlation in tumor metabolic response and no association in lung FDG activity between during RT scans and 3 months post-RT scans in patients with NSCLC. Additional study with a large number of patients is needed to validate these findings.

MR imaging of levator ani muscle recovery following vaginal delivery.

Abstract: Our aim was to quantify the changes that occur in the levator ani muscles (LA) after vaginal delivery using magnetic resonance imaging. Fourteen women underwent MRI 1 day postpartum. Six of them were also scanned 1, 2, 6 weeks and 6 months after delivery. LA signal intensities and thickness, in areas of the urogenital and the levator hiatus were assessed in the transverse plane. Perineal body position was measured in the sagittal plane. One day postpartum a higher T2-signal intensity of the LA compared to the obturator internus muscle was found in all women and a lower T1-signal intensity in 8 of 12 women. By 6 months these differences were present in only 1 woman in the left LA. An elevation in perineal body position of 13.4 ±7.3 mm (P<0.05), as well as a decrease in the area of the urogenital hiatus by 27% (P<0.05) and of the levator hiatus by 22% (P<0.05) by 2 weeks postpartum suggest a return of normal LA geometry. LA thickness showed interindividual variations, and a complete loss of LA tissue was found in 1 woman. Changes in LA signal intensity, topography and thickness during the puerperium can be documented using MR imaging.

Pulmonary nodule volumetric measurement variability as a function of CT slice thickness and nodule morphology.

OBJECTIVE The purpose of our study was to assess differences in volumetric measurements of pulmonary nodules obtained using different CT slice thicknesses; correlate these differences with nodule size, shape, and margination; and compare measurements generated by two different software packages. MATERIALS AND METHODS Seventy-five individual nodules identified on 29 lowdose, unenhanced, MDCT chest examinations were selected for volumetric analysis. Each image data set was reconstructed in three ways (slice thickness/reconstruction interval): 1.25 mm/0.625 mm, 2.5 mm/2 mm, and 5 mm/2.5 mm. Volumetric measurements were made on all 75 nodules at 1.25- and 2.5-mm slice thicknesses and on 57 of 75 nodules at the 5-mm thickness using Volume Analysis software. For 69 of 75 nodules, measurements were obtained on 1.25- and 2.5-mm-thick sections using a different commercially available software system, LN500 R2 software. Volume variability between different slice thicknesses was correlated with nodule diameter, shape, and margination using multiple linear regression. Percent differences between measurements obtained with the two software systems were calculated. Significance of relative volume differences between slice thicknesses and software packages was assessed using a one-sample Students t-test. RESULTS Although statistically significant differences in volumes between different section thicknesses were seen only for the tiny nodule size group, many individual nodules showed substantial volume variation. Significant differences were seen in nodule volume variability for smaller nodules (3-10 mm) compared with larger nodules (> or = 11 mm) (p < 0.0001), as well as spiculated compared with smooth nodules, within a single size group (p < 0.05). No effect of nodule shape (round vs elongated) was noted. Statistically significant differences in measurements obtained with the two software systems were seen only with 2.5-mm-thick sections (p = 0.001). CONCLUSION CT slice thickness variation resulted in significant differences in volume measurements for tiny nodules. A spiculated margin was shown to have a significant effect on nodule volume variability within a single size group. Use of different software packages resulted in significant volume measurement differences at the 2.5-mm CT slice thickness.

Magnetic resonance imaging anatomy of the female urethra: A direct histologic comparison**

Objective To define the urethral structures visible on magnetic resonance imaging (MRI) relevant to stress urinary incontinence. Methods The urethra and surrounding tissues were harvested from 13 female cadavers (ages 21–81) and fixed in 10% buffered formalin. High-resolution T1- and T2-weighted images were obtained at 1.5 tesla. Mallory trichrome-stained histologic sections were prepared in corresponding planes from the cadaveric specimens. Immunohistologic stains for smooth muscle (actin) and vascular endothelium (CD-34 and factor VIII) were obtained on two specimens. Histology and MRI were compared using side-by-side correlation of projected images and by superimposing projected images. Comparison was also made to a non-cadaveric urethral MRI of a 29-year-old woman and to the MRI of another specimen imaged pre- and post-fixation. Results Distinct layers of the cadaveric urethra were seen best on proton density and T2-weighted images. From the center to the periphery, a series of concentric rings were visible: an inner bright ring, the mucosa; a dark ring, the submucosa; an outer bright ring, the smooth muscle of the urethra in a loose connective tissue matrix; and a peripheral dark ring, the striated urogenital sphincter muscle of the urethra in dense connective tissue. No significant alterations were caused by fixation. These cadaveric images matched the non-cadaveric MRI of the 29-year-old woman. Conclusion The internal urethral anatomy visible on high-resolution MRI can be identified and confirmed histologically, and these findings may form the basis for future anatomic investigation of stress urinary incontinence and other urethral abnormalities.

Aortic Intimal Tears: Detection with Spiral Computed Tomography

PURPOSE To determine the frequency, locations, and sizes of aortic intimal tears detected using spiral computed tomography (CT). METHODS CT scans (26 single detector and 26 multidetector studies) from 52 patients with an unoperated aortic dissection and a patent false lumen were evaluated on a workstation. The number, location, and size of aortic tears were recorded and compared between the following groups: acute and chronic dissection, type A and type B, and single detector and multidetector studies. RESULTS In 52 patients, 129 tears were identified (mean 2.48 per patient, median 2, range 1-7). There were no significant differences in the number or size of tears between the acute and chronic, the type A and type B, or the single detector and multidetector groups (p>0.05). The most common locations for tears were the descending aorta (57, 44%) and the juxtarenal region (26, 20%). Within the type B category, there was no significant difference in tear locations between the acute and chronic groups (p>0.05). The majority of tears (88, 68%) were < or =1 cm in each dimension. Tears in the thoracic aorta were significantly larger than abdominal aortic tears (p<0.05). CONCLUSIONS All patients with an aortic dissection and a patent false lumen demonstrated one or more aortic intimal tears using spiral CT. Although most tears were small (</=1 cm), they were usually easily visualized.

Frequency and spectrum of errors in final radiology reports generated with automatic speech recognition technology.

PURPOSE Automatic speech recognition technology has a high frequency of transcription errors, necessitating careful proofreading and report editing. The purpose of this study was to determine the frequency and spectrum of significant dictation errors in finalized radiology reports generated with speech recognition technology. METHODS All 265 radiology reports that were reviewed in preparation for 12 consecutive weekly multidisciplinary thoracic oncology group conferences were examined for significant dictation errors; reports were compared with the corresponding imaging studies. In addition, departmental radiologists were surveyed regarding their estimates of overall and individual report error rates. RESULTS Two hundred six of 265 (78%) reports contained no significant errors, and 59 (22%) contained errors. Report error rates by individual radiologists ranged from 0% to 100%. There were no significant differences in error rates between native and nonnative English speakers (P > .8) or between reports dictated by faculty members alone and those dictated by trainees and signed by faculty members (P > .3). The most frequent types of errors were wrong-word substitution, nonsense phrases, and missing words. Fifty-five of 88 radiologists (63%) believed that overall error rates did not exceed 10%, and 67 of 88 radiologists (76%) believed that their own individual error rates did not exceed 10%. CONCLUSIONS More than 20% of our reports contained potentially confusing errors, and most radiologists believed that report error rates were much lower than they actually were. Knowledge of the frequency and spectrum of errors should raise awareness of this issue and facilitate methods for report improvement.

Radiologic staging of lung cancer.

Preoperative tumor staging in patients with known or suspected non-small cell lung cancer is generally performed using contrast enhanced chest computed tomography (CT) (including the adrenal glands). Abdominal CT is generally unnecessary, given the low frequency of isolated liver metastases. The role of MRI is limited, and it is used mainly as a problem solving tool in certain specific situations. A CT showing no mediastinal lymph node enlargement usually oviates preoperative mediastinal lymph node sampling, with certain exceptions. If enlarged mediastinal lymph nodes are demonstrated at CT, then CT may be used to direct preoperative lymph node sampling via transbronchoscopic Wang needle biopsy, mediastinoscopy, mediastinotomy, or video assisted thoracoscopy.