Helical Computed Tomography Scans Research Articles

乳腺内視鏡手術と3D-CT乳腺リンパ管造影＜その2＞3D-CT乳腺リンパ管造影によるセンチネルリンパ節生検

Background: I have studied endoscopic surgery for breast diseases and 3-dimensional (3D) computed tomographic (CT) lymphography for sentinel node (SN) biopsy. In this second in a series of reports, I explain the techniques of 3D-CT lymphography. 3D-CT lymphography can show the detailed lymphatic flow from the breast tumor toward the SNs and the exact local relation between axillary lymph nodes. I have developed this 3D image-processing system to more precisely depict the anatomical structures of the mammary lymphovascular system. This system allows us to systematically collect axillary lymph nodes, including SNs. Methods: 3D-CT lymphography was performed to mark SNs on the skin on the day before surgery. Above the tumor and near the areola, 2ml of Iopamiron 300 was injected subcutaneously. Sixteen-channel multidetector-row helical CT scan images were obtained 1 minute after injection to detect SNs, and after 3 and 5 minutes to observe lymph flow into the venous angle. The scan images were reconstructed to produce 3D images. SN biopsy was performed with the dye-staining method and endoscopy. Results: 3D-CT lymphography accurately showed lymphatic flow from the tumor to SNs. We classified the relationship between the lymph ducts and the drained SNs into 4 patterns. Following up 3 and 5 minutes after injection of the contrast agent, we can follow the lymph ducts beyond the SN into the second and third nodes toward the venous angle with the complex plexus. The figure of the axillary nodes shows 5 beads-like grouped nodes. 3D-CT lymphography can also recognize the metastatic patterns of the enhanced lymph node. These patterns will predict the metastasis before SN biopsy. 3D-CT lymphography can also be used to detect lymph flow from the arm to avoid harming the arm lymph channel during axillary node dissection and SN biopsy. Conclusions: With 3D-CT lymphography, we can more accurately and precisely recognize lymph flow and the positional relations of SN and axillary nodes to surrounding anatomical structures.

Performance of a near-real-time KBr:Eu dosimetry system under computed tomography x-rays

Abstract The dynamic radiation fields used in Computed Tomography (CT) scans are difficult to characterize quickly using dosimetry techniques that utilize large-volume detectors (e.g. ionization chambers) or passive detectors (e.g., thermoluminescent dosimeters). In this study we demonstrate the feasibility of using the optically stimulated luminescence (OSL) of KBr:Eu for quantitative CT dose measurements. The particular OSL method used is capable of acquiring full OSL signals at a rate of 10 Hz, which allows for near-real-time active dosimetry. The portable reader system connects to the KBr:Eu dosimeter via a fiber-optic cable, through which both stimulation light and OSL propagate. The small volume (∼2 mm 3 ) of the KBr:Eu dosimeter also allows the system to resolve detailed structures in complex radiation fields. Testing of the KBr:Eu dosimetry system under axial and helical CT scanning showed that the fast data acquisition and small dosimeter volume allowed for high-resolution dose profiling using a cylindrical CT body phantom. The dose response of the dosimetry system compared favorably to exposure results reported by a standard 100 mm pencil ionization chamber. A dependence of the OSL output from the KBr:Eu crystal on x-ray energy was also observed. These and similar observations are discussed in detail.

The Impact of Spontaneous Ventilation on Distribution of Lung Aeration in Patients with Acute Respiratory Distress Syndrome: Airway Pressure Release Ventilation Versus Pressure Support Ventilation

In this study, we sought to determine which mode, airway pressure release ventilation (APRV) or pressure support ventilation (PSV), decreases atelectasis more in patients with acute lung injury/acute respiratory distress syndrome (ARDS). This was a retrospective study in the intensive care unit. Between 2006 and 2007, we identified 18 patients with acute lung injury/ARDS who received either APRV or PSV and had a helical computed tomography scan twice in 3 days. Computed tomography data from the APRV and PSV groups (n = 9 each) were analyzed for 3-dimensional reconstruction and volumetry. Aerated lung regions (normally aerated, poorly aerated, nonaerated, and hyperinflated) were identified by their densities in Hounsfield units. The Pao(2)/Fio(2) ratio and alveolar-arteriolar oxygen gradient after ventilation were improved in both groups (P = 0.008); however, the improvements in the APRV group exceeded those in the PSV group when delivered with equal mean airway pressure (P = 0.018 and 0.015, respectively). Atelectasis decreased significantly from 41% (range, 17%-68%) to 19% (range, 6%-40%) (P = 0.008) and normally aerated volume increased significantly from 29% (range, 13%-41%) to 43% (range, 25%-56%) (P = 0.008) in the APRV group, whereas lung volume did not change in the PSV group. Spontaneous ventilation during APRV improves lung aeration by decreasing atelectasis. PSV for gas exchange is effective but not sufficient to improve lung aeration. These results indicate that APRV is more efficient than PSV as a mode of primary ventilatory support to decrease atelectasis in patients with ARDS.

Ureteral calculi imaging: a literature review comparing plain film studies, contrast media studies, ultrasound and computed tomography

AbstractPurpose: Through a study of the literature this paper aims to investigate the imaging pathway which should be undertaken by patients presenting to the emergency department with renal colic and flank pain. Method: The British Journal of Radiology, Journal of Endourology, Radiology, RadioGraphics, American Journal of Radiology and Adult Urology were searched to find any previous studies into this area through the use of keywords: calculi, renal, computed tomography (CT), plain imaging, abdominal, ultrasound, intravenous urogram (IVU) and x‐ray. Conclusion: This literature review determined that the use of non‐enhanced helical CT scanning of the abdomen and pelvis should be utilised as the initial imaging technique. CT is able to demonstrate all stones, can be performed rapidly and can diagnose other pathologies which may be mimicking renal colic. Plain film and contrast imaging studies including intravenous urography (IVU) are seen as being of little diagnostic value for frontline identification due to their inability to demonstrate a large number of stones due to size, location and composition. Ultrasound has been shown to be of use as a tool for pregnant or paediatric patients, however its inability to accurately demonstrate the ureters and diagnose extra‐urinary pathology limits its use for the general population. The use of low‐dose CT is also discussed, and its use advocated for patients with repeat presentation of these symptoms. As more eduction is provided into this area, the authors believe this will become the modality and technique of choice. An imaging pathway flowchart devised by this review is provided.

The value of multidetector-row CT in the preoperative detection of pancreatic insulinomas

The authors sought to quantitatively analyse enhancement characteristics of pancreatic insulinomas in different phases and determine the value of multidetector-row computed tomography (CT) for detecting insulinomas. Forty-six patients with surgically proven insulinomas diagnosed between 2002 and 2007 were retrospectively reviewed. These patients underwent single-phase (group 1) or dual-phase (group 2) helical CT scanning. Sensitivity for detecting insulinomas in group 2 was superior to that in group 1 (p<0.05).The sensitivity for insulinoma detection in the arterial phase was superior to that in the portal-venous phase (p<0.05). The mean attenuation values of the insulinomas and normal pancreas during the unenhanced arterial and portal-venous phases were, respectively, 40.5+/-8.75 HU (Hounsfield units), 114.48+/-27.30 HU, 112.19+/-19.52 HU and 44.56+/-6.48 HU, 81.16+/-15.22 HU, 90.54+/-13.80 HU, and there was statistical difference between them (p=0.000). The contrast enhancement of insulinomas in the arterial and portal-venous phases was 74.03+/-29.51 HU and 70.90+/-21.93 HU, respectively, and there was no statistical difference between them (p=0.499). The tumour to normal-pancreas attenuation differences in the arterial and portal-venous phases were respectively 33.32+/-20.96 HU and 20.58+/-16.32 HU, respectively, and there was statistical difference between them (p=0.011). Dual-phase CT has a promising sensitivity in detecting pancreatic insulinomas. The acquisition of images in the arterial phase is more helpful for detecting insulinomas.

Determining Size and Characteristics of Metal Intraocular Foreign Bodies Using Helical CT Scan

To carry out a pilot study comparing the size of various types of metallic intraocular foreign bodies as imaged on computed tomographic (CT) scan to their actual size, and to determine the features of different types of metals on CT scan. Metallic foreign bodies of predetermined standardized sizes were prepared from iron, silver, copper, aluminium, and lead. The metallic pieces/shards were each inserted into the vitreous of a cow's eye and helical CT scan (MX twin, Picker) was performed to image the intraocular foreign bodies, using soft tissue and bone window settings. Slice section thickness was 1.3 mm, with intervals of 0.6 mm. Milliampere per second was 265 and pitch 0.7. The size of all types of metals as measured on CT was larger than the actual size. Iron was enlarged by a factor of 2.29, silver 1.77, copper 1.26, and aluminum 1.17. All metals had features including central core, ring density, and artifacts which varied for each type of metal, giving each one a characteristic appearance Helical CT scan could be useful in estimating the type and size of an intraocular metal foreign body made from iron, silver, copper, aluminium, or lead.

Evaluation of medial acetabular wall bone stock in patients with developmental dysplasia of the hip using a helical computed tomography multiplanar reconstruction technique

The technique of medialization has been used to reconstruct acetabula at the level of true acetabula in total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH). Appreciation of the bone stock in the medial acetabular wall is significant for making an optimal acetabular reconstruction plan and avoiding complications. To evaluate the bone stock of the medial acetabular wall and its relation to the degree of subluxation in patients with DDH using computed tomography (CT). Helical CT scans of 27 hips were obtained from 21 patients with osteoarthritis secondary to DDH who were scheduled for total hip arthroplasty. Eleven hips belonged to Crowe class I, while 16 hips belonged to Crowe class II/III. The raw CT data were reprocessed in various planes by scrolling multiplanar reformation (MPR). Acetabular opening, depth, and medial bone stock, as indicated by the minimum thickness of the medial acetabular wall, were measured in the transverse reformed MPR plane. The minimum thicknesses of the medial acetabular wall in Crowe-I and Crowe-II/III hips were 3.8+/-2.1 mm and 7.1+/-3.1 mm, respectively, with statistically significant differences between the groups (P<0.05). Furthermore, the bone stock in the medial acetabular wall correlated with the degree of subluxation (R=0.69) and the acetabular depth (R= ;- ;0.71). There was significantly more bone stock in the medial acetabular wall in patients with higher-degree subluxation than there was in the less-severe class. This difference should be taken into consideration when reconstructing acetabula in THA in patients with DDH using the technique of medialization.

8046 Preliminary results of the ENDORAD trial: RAD001 (everolimus) monotherapy as second-line or third-line treatment of endometrial carcinoma: a phase II trial of GINECO group

Purpose: To evaluate an online image-guidance strategy for conformal treatment of prostate cancer and to estimate margin-reduction benefits.Methods and Materials: Twenty-eight patients with at least 16 helical computed tomography scans were each used in this study. Two prostate soft-tissue registration methods, including sagittal rotation, were evaluated. Setup errors and rigid organ motion were corrected online; non-rigid and intrafraction motion were included in offline analysis. Various clinical target volume-planning target volume (CTV-PTV) margins were applied. Geometrical evaluations included analyses of isocenter shifts and rotations and overlap index. Dosimetric evaluations included minimum dose and equivalent uniform dose (EUD) for prostate and gEUD for rectum.Results: Average isocenter shift and rotation were (dX,dY,dZ,θ) = (0.0 ± 0.7,−1.1 ± 4.0,−0.1 ± 2.5,0.7° ± 2.0°) mm. Prostate motion in anterior-posterior (AP) direction was significantly higher than superior-inferior and left-right (LR) directions. This observation was confirmed by isocenter shift in perspectives AP (1.8 ± 1.8 mm) and RL (3.7 ± 3.0 mm). Organ motion degrades target coverage and reduces doses to rectum. If 2% dose reduction on prostate D99 is allowed for 90% patients, then minimum 3 mm margins are necessary with ideal image registration.Conclusions: Significant margin reduction can be achieved through online image guidance. Certain margins are still required for nonrigid and intrafraction motion. To further reduce margin, a strategy that combines online geometric intervention and offline dose replanning is necessary.

The Aortic Root: Comparison of Measurements From ECG-gated CT Angiography With Transthoracic Echocardiography

The purpose of this study was to compare the measurements of the aortic root obtained from electrocardiographically (ECG)-gated computed tomography (CT) angiography (CTA) to the measurements obtained from transthoracic echocardiography (TTE). This was a retrospective study in a patient population scanned at our institution between December 2005 and January 2007 with retrospectively ECG-gated CTA. ECG-gated CTA was performed with a 64-section helical CT scanner (Light speed, VCT, GE, Milwaukee, WI). Sixty-eight patients; 51 men and 17 women were included in this study. Aortic root diameters were measured by using double oblique reconstruction from axial source images. The TTE measurements of the aortic root were obtained from the reports that were performed within 2 months of CTA. The average aortic root diameter measured by TTE was 33+/-4.1 mm; on CTA it was 36.9+/-3.8 mm. The median difference between the 2 measurements was 3.9 mm which was significant (P<0.0001). In patients whose aortic root measurements with CTA were normal, the TTE measurements were also normal. However, in the group of patients with dilated aortic roots by CTA, TTE measurements were significantly lower and many were normal. In the group of patients with dilated aortic root by TTE, the CTA measurements of the aortic root were similarly increased. Retrospective comparison of TTE and CTA measurements of the aortic root reveal that TTE measurements are substantially lower or even normal in patients found to have dilated aortic root by CTA.

Small (≤2 cm) atypical hepatic haemangiomas in the non-cirrhotic patient: pattern-based classification scheme for enhancement at triple-phase helical CT

The aim of this study was to determine by triplephase helical computed tomography (CT) the appearance of atypical small (< or = 2 cm) hepatic haemangiomas (HHs) in the non-cirrhotic patient. We retrospectively reviewed the hepatic arterial-dominant phase (HAP), portal venous phase (PVP) and delayed-phase (DP) helical CT images of 47 patients with 52 atypical small (< or = 2 cm) HHs associated with 34 typical small HHs. Images were assessed to identify the patterns of enhancement of atypical HHs and correlate their appearance with that of typical small HHs in the delayed phase. Interobserver variability and kappa value were calculated. Statistical significance was calculated by the Fisher exact test. The 52 atypical small HHs were categorised as follows: type 1a (hyperattenuating in the HAP, n=17), type 1b [hyperattenuating with transient hepatic attenuation difference (THAD) around the lesion in the HAP, n=12], type 2a (homogeneously hypoattenuating in the HAP or PVP, n=9), type 2b (hypoattenuating with "bright-dot" sign in the HAP or PVP, n=13) and type 3 (hypoattenuating with central enhancing area, n=1). Interobserver agreement was perfect for HHs of types 1a, 1b, 2a and 3. On DP images, the appearance of atypical small HHs was identical to that of typical small HHs in all cases (p<0.0001), with lesions showing homogeneous isoattenuation to the aorta or liver parenchyma without peripheral capsule. Triple-phase helical CT scans can distinguish several types of atypical small HHs. The demonstration of patterns similar to those of typical forms on DP CT is fundamental for the diagnosis.

Computed tomography diagnosis of cardiovascular involvement in Behcet syndrome

Objective To evaluate the computed tomography (CT) characteristics of cardiovascular involvement in Beheet syndrome. Methods Eleven patients with clinically diagnosed Behcet syndrome were studied retrospectively from July 1995 to December 2007. Electron beam CT or 64-slice helical CT scanner was used and CT characteristics were reviewed. Results Eleven patients were diagnosed according to the criteria reported by the international study group for Behcet syndrome. Of them, 4 patients presented with aortic valve prolapse (2 patients with mitral valve prolapse), false aneurysm of right coronary artery was demonstrated in 2 patients, false aneurysm of left subclavian artery, aortic aneurysm and penetrating ulcers, aortic arch false aneurysm, aortic dissection, pulmonary embolism and interatrial scptum aneurysm in 1 case, respectively. Conclusion CT is a very useful method for the diagnosis and foUow-up of Behcet syndrome. Key words: Behcet syndrome ; Aneurysm; Aortic valve insufficiency; Tomography, X-ray computed

SU‐FF‐I‐08: Ramping and Overscanning Contributions to Patient Dose in Helical CT

Purpose: In helical computed tomography (CT) scans, slices adjacent to the clinical volume of interest, known as z overscanning lengths, are acquired for reconstruction. Additionally, CT machines undergo a transient power state, known as tube ramping, to reach full power. This investigation will characterize the dependence of tube ramping time and z overscanning length on pitch, rotation time, beam collimation, and reconstruction slice width. These relationships will be utilized to determine the contributions to patient dose. Methods and Materials: A real‐time fiber optic coupled dosimetry system with 10 ms temporal resolution is interfaced with three organic scintillators with 0.157 mm3 volumes. A Siemens Somatom Sensation 16 multislice helical CT scanner is used for the study with pitches varying from 0.5 to 1.5; rotation speeds between 0.5 and 1.5 seconds per rotation; reconstructed slice widths of 2.0 to 10.0 mm; and beam collimation of either 12 or 24 mm. One dosimeter remains stationary while two dosimeters are translated through the beam to provide real‐time profiles of the x‐ray field. Results: The ramping time was found to be independent of pitch and represented 0.5% of the total scan time. The z overscanning length was found to be monotonically increasing with pitch and represents anywhere from 14.3% to 35.9% of the total scan length. Conclusions: While ramping time remained constant, it has been demonstrated that z overscanning length is heavily dependent upon pitch — a high pitch added 7.1 cm to a 20.3 cm clinical scan length. Both z overscanning and ramping time must be taken into consideration when planning and managing patient dose. The effect of rotation time, beam collimation, and reconstruction slice width on ramping time and z overscanning length will be investigated in future work.

Evaluation of Obstructive Sleep Apnea Syndrome by Computational Fluid Dynamics

The amelioration of obstructive sleep apnea syndrome (OSAS) by maxillomandibular advancement (MMA) surgery can be predicted by analyzing anatomical airway changes with 3-dimensional (3D) geometrical reconstruction and computational fluid dynamics. Computer Enabling Technology Lab (ETLab) and Computational Simulation Lab (CSLab) can be used to analyze anatomic airway change for previously operated patients with a clinical cure of OSAS. MMA surgery reduces airway resistance and pressure effort (gradient) of OSAS by increasing the dimension of the airway. ETLab has been used to reconstruct the upper airway as a 3D computer model (bone and soft tissue surrounding the pharyngeal airway) from existing helical computed tomography scan format of OSAS patients. ETLab can compare and construct the geometry with numerical meshes of the airway between pre- and postoperative MMA by the use of bioengineering software. This technology uses high-fidelity computation fluid dynamic simulations, developed at the CSLab, for prediction and analysis of the flow field in the airway for pre- and postoperative MMA. It is possible to use the simulation to predict the likely success of future treatment and develop a prognostic factor. The soft- and hard-tissue mesh is used to determine the pre- and postoperative differences in the facial and pharyngeal tongue base for soft-tissue change associated with hard-tissue movement. This correlation predicts the amount of surgical movement necessary to create an adequate airflow. These results help define the surgical techniques in OSAS for more precise identification of upper airway anatomical features. This process correlates the area and pressure change at the velopharynx, oropharynx, and retroglossal space of the upper airway by the ETLab. Results can compare with polysomnogram and cure rates. 3D computer analysis can be used to test flow dynamics in the human airway for surgical treatment of OSAS.

Long-Term Follow-Up of Aortic Involvement in Giant Cell Arteritis

To date, only a few series have analyzed the long-term outcome of giant cell arteritis (GCA) patients with aortic involvement, which prompted us to conduct the current retrospective study. Our aims were to 1) determine the prevalence of GCA in patients exhibiting nonatherosclerotic aortic involvement (that is, aortitis, aortic ectasia, and/or aneurysm); and 2) evaluate clinical features and long-term outcome of GCA patients exhibiting aortitis, aortic ectasia, and/or aortic aneurysm.From January 1997 to March 2008, 66 consecutive patients in the Department of Internal Medicine at the University of Rouen medical center received a diagnosis of nonatheromatous aortic complications (aortitis, aortic ectasia, and/or aneurysm). In these 66 patients, aortic involvement was related to GCA (n = 48), Takayasu arteritis (n = 6), relapsing polychondritis (n = 1), and infection (n = 11).Of the 48 patients with GCA, aortic involvement preceded the initial GCA diagnosis in 1 patient. Aortic involvement was identified in association with GCA in 40 patients (83.3%), and developed after the onset of GCA in the 7 remaining patients (14.6%). Aortic involvement was more often asymptomatic (77.1%). The aortic helical computed tomography (CT)-scan procedure principally showed isolated aortitis (circumferential thickening of the aortic wall >3 mm) in 41 patients (85.4%). In the remaining 7 patients with GCA (14.6%), aortic helical CT scan demonstrated aortic thoracic ectasia and aortitis (n = 3), aortic thoracic aneurysm and both thoracic and abdominal aortitis (n = 3), and both aortic abdominal aneurysm and aortitis (n = 1). All patients were given steroid therapy at a median daily dose of 1 mg/kg initially.At 6-month follow-up, 34 of 48 patients systematically underwent both thoracic and abdominal CT scan. Aortic helical CT scan demonstrated complete disappearance of aortitis in 8.8% of patients, improvement of aortitis in 47.1%, unchanged pattern of aortitis and/or aortic thoracic ectasia/aneurysm in 41.2%, and deterioration of aortic thoracic aneurysm in 1 patient (2.9%). At 18-month follow-up, 11 patients systematically underwent both thoracic and abdominal CT scan. Aortic helical CT scan showed complete disappearance of aortitis (n = 1), improvement of aortitis (n = 1), unchanged pattern of aortic thoracic ectasia/aneurysm (n = 2), and deterioration of aortic thoracic aneurysm (n = 1). At patients' last follow-up, the median daily dose of prednisone was 7 mg. Steroid therapy could be discontinued in 17 patients (35.4%).The current retrospective study suggests that aortic impairment may be more prevalent than previously reported. Our findings suggest that specific inflammatory thickening of the aortic wall is common at the time of GCA diagnosis, and that aortitis may be the first manifestation of GCA-associated aortic complications. Whether isolated aortitis leads to vascular wall injury responsible for late-onset aneurysmal disease remains to be determined. At this time, we recommend long-term monitoring for aortic aneurysms, especially in high-risk subjects, although the optimal frequency and imaging modality have not yet been determined. A yearly screening strategy for thoracic/abdominal aortic aneurysms has been proposed for patients with GCA, including physical examination, 2-view chest radiograph, and abdominal ultrasound.

Statistical characteristics of streak artifacts on CT images: Relationship between streak artifacts and mA s values

The purpose of this study is to investigate how streak artifacts on computed tomography (CT) images vary with reduction in radiation doses by assessing the quantitative relationship between the streak artifacts and milliampere-time product (mA s) values. A commercially available chest phantom was used to measure the streak artifacts on the CT images obtained using a 4- and 16-multidetector-row helical CT scanners with various mA s values at a constant tube voltage of 120 kVp. The cardiac slice image was employed as a target image for evaluating the streak artifacts on the CT image. Eighty parallel line segments with a length of 20 pixels were placed perpendicular to numerous streak artifacts on the cardiac slice image, and the largest difference between adjacent CT values in each of the 80 CT-value profiles of these line segments was employed as a feature variable of streak artifacts; these feature variables have been analyzed by the extreme value theory. The largest difference between adjacent CT values in each CT-value profile can be statistically modeled by a Gumbel distribution. Further, the maximum level of streak artifacts on CT images that will be tolerated for clinical use and low-dose CT screening examination was expected to be estimated using the location parameter in the Gumbel distribution.

Evaluation of tumor response after locoregional therapies in hepatocellular carcinoma

Evaluation of response to treatment is a key aspect in cancer therapy. Response Evaluation Criteria in Solid Tumors (RECIST) are used in most oncology trials, but those criteria evaluate only unidimensional tumor measurements and disregard the extent of necrosis, which is the target of all effective locoregional therapies. Therefore, the European Association for the Study of the Liver (EASL) guidelines recommended that assessment of tumor response should incorporate the reduction in viable tumor burden. The current report provides an assessment of the agreement/concordance between both RECIST and the EASL guidelines for the evaluation of response to therapy. The authors evaluated a cohort of 55 patients within prospective studies, including 24 patients with hepatocellular carcinoma who underwent transarterial chemoembolization (TACE) with drug eluting beads (DEB-TACE) and 31 patients who underwent percutaneous ablation (percutaneous ethanol injection [PEI]/radiofrequency [RF]). Triphasic helical computed tomography scans were performed at baseline, at 1 month, and at 3 months after procedure, and 2 independent radiologists evaluated tumor response. Evaluating response according to RECIST criteria, no patients achieved a complete response (CR), 21.8% of patients achieved a partial response (PR) (none in the PEI/RF group), 47.3% of patients had stable disease (SD), and 30.9% of patients had progressive disease (PD). When response was evaluated according to the EASL guidelines, 54.5% of patients achieved a CR, 27.3% of patients achieved a PR, 3.6% of patients had SD, and 14.5% had PD. The kappa coefficient was 0.193 (95% confidence interval, 0.0893-0.2967; P < .0001). RECIST missed all CRs and underestimated the extent of partial tumor response because of tissue necrosis, wrongly assessing the therapeutic efficacy of locoregional therapies. This evaluation should incorporate the reduction in viable tumor burden as recognized by nonenhanced areas on dynamic imaging studies.

Estudo tomográfico do atlas relacionado com a inserção de implantes na massa lateral

INTRODUÇÃO: A técnica de Harms para a realização da artrodese atlantoaxial possibilita o uso de manobras de redução transoperatória da subluxação atlantoaxial e facilita a fixação dessa articulação, principalmente nos pacientes hipercifóticos e nas situações em que há impossibilidade da fixação com o parafuso transarticular C1-C2. OBJETIVOS: descrever os parâmetros morfométricos do atlas relacionados à técnica de Harms para a artrodese C1-C2, o trajeto ideal e o corredor de segurança da inserção do parafuso na massa lateral do atlas mensurados através de imagens de reconstrução multiplanar com tomografia computadorizada helicoidal nos planos. MATERIAIS E MÉTODOS: trinta atlas de origem local foram submetidos a tomografia computadorizada e mensurados com cursor digital. RESULTADOS: o comprimento posteroanterior do implante mediu 16,5 mm à direita e 16,3mm à esquerda. Quando utilizando como ponto de entrada na porção central da massa lateral imediatamente inferior ao arco posterior, o trajeto deve ter uma congruência de 15º no plano coronal e uma angulação superior de 20º no plano sagital. CONCLUSÃO: O corredor de segurança para um parafuso na massa lateral teria uma inclinação inferior de 22º e superior de 33º no plano sagital e no plano axial de 36º medial e 26º lateral.

‘Virtual Colonoscopy’ – What’s in a Name?

After hearing about the risks associated with colonoscopy, a patient asks “What about virtual colonoscopy?” The message she received is clear – there is a test that is essentially equivalent to a real colonoscopy but without the risks or discomfort that are associated with the actual procedure. Computed tomography (CT) colonography or spiral CT scanning of the colon is presented to the public with a label that includes an embedded message – ‘this is a good test that rivals colonoscopy.’ Mislabelling has been fairly common in medicine, often the result of a misunderstanding of the underlying cause of a symptom or disease. Dyspepsia (ie, indigestion) is not really due to a defect of the digestive process, and we have come to understand that ‘heart burn’ has nothing to do with the heart. An elderly physician once told me that in the early days of his practice people were said to die of ‘acute indigestion’, a term eventually replaced with ‘myocardial infarction’ or ‘heart attack’ when we came to understand what was actually happening to these patients. However, ‘virtual colonoscopy’ is not a label that comes from a misunderstanding of its nature or value. It is a label directed at the consumer and actually seeks to place the procedure in a position of some equivalency with colonoscopy. Is this OK? Is it acceptable to embed a marketing message in the name of an option for a consumer who needs to make an important choice among a range of screening options? Such labelling is, after all, quite effective at influencing consumers. Are the strategies of consumer advertising germane to or even ethical in the world of medicine? Is it not objectivity and accuracy that we must provide to patients? Language evolves and becomes normative from general use. It becomes difficult to expunge a term from our common discourse once we have reached a certain level of familiarity and comfort with it. Those who have sought to change the language of ‘stroke’ to ‘brain attack’ have found this to be a difficult proposition. It is still relatively early in our experience with CT imaging of the colon, so we still have an opportunity to reconsider the use of the term ‘virtual colonoscopy’. In the interest of objectivity, I suggest that we should call a thing what it is and not label it in a way that suggests something about its relative efficacy or risk. When I talk to patients about their use of analgesic combinations containing acetaminophen and codeine, I discuss their use of codeine; I do not use the name of the commercial preparation they are taking (why would one name a combination of drugs after the ingredient that provides only minor efficacy in the formulation and tag the narcotic component – the one with addictive potential – as a number?). I suggest that we cease and desist in our use of the term ‘virtual colonoscopy’ and call the procedure what it is. It is CT colonography, or spiral or helical CT scanning of the colon. This is the language that I use when discussing this procedure with patients. As physicians, we should strive to make the language of medicine as objective, accurate and meaningful as we can, understanding that ultimately we may have little impact on the lingua franca.

The Role of Seminal Vesicle Motion in Target Margin Assessment for Online Image-Guided Radiotherapy for Prostate Cancer

For patients with intermediate- and high-risk prostate cancer, the seminal vesicles (SVs) are included in the clinical target volume (CTV). The purposes of this study are to investigate interfraction motion characteristics of the SVs and determine proper margins for online computed tomography image guidance. Twenty-four patients, each with 16 daily helical computed tomography scans, were included in this study. A binary image mask was used for image registration to determine daily organ motion. Two online image-guided radiotherapy strategies (prostate only and prostate + SVs) were simulated in a hypofractionated scheme. Three margin designs were studied for both three-dimensional conformal radiotherapy and intensity-modulated radiotherapy (IMRT). In prostate-only guidance, Margin A was uniformly applied to the whole CTV, and Margin B was applied to the SVs with a fixed 3-mm prostate margin. In prostate plus SV guidance, Margin C was uniformly applied to the CTV. The minimum margins were sought to satisfy the criterion that minimum cumulative CTV dose be more than those of the planning target volume in the plan for greater than 95% of patients. The prostate and SVs move significantly more in the anterior-posterior and superior-inferior than right-left directions. The anterior-posterior motion of the prostate and SVs correlated (R(2) = 0.7). The SVs move significantly more than the prostate. The minimum margins found were 2.5 mm for three-dimensional conformal radiotherapy and 4.5, 4.5, and 3.0 mm for Margins A, B, and C for IMRT, respectively. Margins for IMRT were larger, but the irradiated volume and doses to critical structures were smaller. Minimum margins of 4.5 mm to the SVs and 3 mm to the prostate are recommended for IMRT with prostate-only guidance. The SVs move independently from the prostate gland, and additional margins are necessary for image-guided radiotherapy.

Percutaneous drainage of psoas abscess under real-time computed tomography fluoroscopic guidance

The goal of our study was to determine the usefulness of percutaneous abscess drainage under guidance of computed tomography (CT) fluoroscopy. Our subjects were 21 patients (seven women, 14 men; mean age 64 years; age range 30-87 years) who had undergone percutaneous drainage of 26 psoas abscess lesions under CT fluoroscopic guidance between May 2001 and January 2008. Drainage methods involved a needle puncture, insertion of a guidewire, serial dilations, and the exchange of the needle with a drainage tube. The procedures were guided by use of a helical CT scanner that provided real-time fluoroscopic reconstruction. Percutaneous drainage under real-time CT fluoroscopic guidance was successfully performed in every procedure. Use of real-time CT fluoroscopy allowed rapid assessment of needle, guidewire, and catheter placement. No patient had serious complications related to the drainage procedure. The mean procedure time required to drain one lesion was 35.6 +/- 13.6 min. Mean period after the drainage procedure until complete disappearance of the abscess as confirmed by CT was 12.4 +/- 10.0 days (range 3-46 days). CT fluoroscopy is useful in achieving accurate and safe drainage of abnormal psoas fluid collections.