Neurological development and iron supplementation in healthy late-preterm neonates: a randomized double-blind controlled trial.

Late-preterm infants (LPT) are at increased risk for long-term neurodevelopmental sequelae and iron deficiency. The aim of the study is to assess the positive effect of iron supplementation on psychomotor development in healthy LPT. We designed a randomized placebo-controlled double-blind trial dividing the newborns into two groups. Every patient was assessed using the Griffiths Mental Development Scales (GMDS)-II edition at 12-month post-conceptional age. The study was performed at the Neonatology Unit of our Hospital, in Italy. Sixty-six healthy LPT infants born between 340/7 and 366/7 weeks of gestational age were enrolled in the study. One group received martial prophylaxis from the third week of life to 6 months of post-conceptional age (2 mg/kg/day of iron pidolate), the other received placebo. Fifty-two of the enrolled infants were assessed using the GMDS at 12-month of post-conceptional age. Statistical analysis of the mean scores of the Griffiths subscales was performed. There was a difference in the mean developmental quotient (DQ) (p < 0.01) between the two groups: iron group mean DQ 121.45 ± 10.53 vs placebo group mean DQ 113.25 ± 9.70. Moreover, mean scores of the Griffiths subscales A, B, and D showed significant differences between the two groups (scale A p < 0.05, scale B p < 0.02, scale D p < 0.01, respectively).Conclusions: We recommend that all LPT neonates receive iron supplementation during the first 6 months of life in order to improve their 1-year neurodevelopmental quotient. What is Known: • Late-preterm infants (LPT) are at increased risk for long-term neurodevelopmental sequelae and also for iron deficiency. • Iron deficiency is an independent risk factor for adverse neurological outcomes. What is New: • Healthy late-preterm who received iron supplementation during the first 6 months of life achieved better neurological outcomes at 12-month post-conceptional age than LPT who received placebo. • Our study strongly supports the need for the implementation of martial prophylaxis in LPT neonates.

Occult spinal dysraphisms in newborns with skin markers: role of ultrasonography and magnetic resonance imaging.

PURPOSE: The purpose of this paper is to investigate occult spinal dysraphisms (OSD) using lumbar ultrasonography (LUS) in newborns presenting with specific skin markers or sacrococcygeal dimple. METHOD: From 2012 to 2015, we performed LUS in newborns with cutaneous stigmata and/or sacroccygeal dimple. Magnetic resonance imaging (MRI) was performed in all patients with abnormal ultrasound or features of neurological involvement in order to detect spinal lesions. RESULTS: We prospectively evaluated 475 newborns who presented cutaneous stigmata performing LUS during their 4 weeks of life though 439 completed the study. All patients had a follow-up of almost 12 months. Of these, 39 presented abnormal ultrasonography and underwent MRI. In this group, spinal dysraphism was confirmed in 12 patients. When considering skin markers, dermal sinus correlated with higher risk of spinal cord lesions, on the other hand the presence of simple sacral dimple alone denoted a very low risk of occult spinal dysraphism. The simultaneous presence of more skin markers and/or the presence of lumbar ultrasonography abnormality regarding the level of the conus, pulsatility, and the position of the cord, thickness of the filum terminale, or the presence of an intratecal mass, lipoma, or dermal sinus tract indicated the necessity to perform MRI in order to detect spinal cord abnormalities because of higher risk of spinal lesions. CONCLUSION: LUS in newborns with specific skin markers is a valid method to select patients in which MRI can be performed to detect OSD. The presence of a simple sacral dimple alone is a negligible marker for occult neural pathology while the presence of isolated dermal sinus or more than one cutaneous marker could be considered indicative of higher risk of spinal dysraphism.

Audiological evaluation in children affected by myelomeningocele.

PURPOSE: The aim of the present study is to evaluate the auditory system in children affected by myelomeningocele and comparing the results with clinical neurological conditions. MATERIALS AND METHODS: Forty-three children, aged between 7 and 26 years, affected by myelomeningocele were investigated by means of subjective tonal audiometry and objective impedance audiometry (tympanometry and acoustic stapedial reflex). RESULTS: Audiological evaluation showed an alteration in 32 patients (74%%). Nine patients presented a mild hearing loss: bilateral in six cases (three sensorineural, one mixed, and two conductive) and unilateral in three cases (two mixed and one conductive). One patient had moderate unilateral conductive deafness and, finally another one severe unilateral sensorineural. Almost all patients with deafness were affected by myelomeningocele and Chiari II. Stapedial-cochlear reflex investigation showed an alteration in 30 patients (70%): 9 of these also showed deafness while the remaining 21 was normal hearing. In these 30 patients, we demonstrated the presence of myelomeningocele, hydrocephalus, and Chiari II malformation in 21 subjects (70%). CONCLUSION: Otoneurological evaluation is important in myelomeningocele not only at the birth but also in the follow-up. It could have an important prognostic role for neurological impairment.

Adrenocortical insufficiency is not a problem in preterm infants treated with antifungal prophylaxis with fluconazole.

AIM: Fluconazole prophylaxis of invasive fungal infections is a cornerstone of neonatal care, but in vitro studies have shown that it inhibits corticosteroid production. This study assessed whether preterm infants demonstrated an association between fluconazole administration, and its duration, and symptoms of adrenocortical insufficiency. METHODS: We compared two groups who were treated before and after we introduced the use of fluconazole to our neonatal intensive care unit. Infants with a gestational age of ≤27 weeks or with a birth weight of ≤750 g were considered for the retrospective analysis. In order to assess whether the duration of prophylaxis was related to adrenocortical insufficiency, regression models were performed in all preterm infants in the fluconazole group. RESULTS: The fluconazole group (n = 37) and nonfluconazole group (n = 41) were compared. No differences were found in the percentage of infants with symptoms of adrenocortical insufficiency, such as hypotension or need of vasopressor therapy. The incidence of hypotension and the use of vasopressor therapy were not related to duration of fluconazole prophylaxis. CONCLUSION: Fluconazole and it duration were not associated with the incidence of symptoms related to adrenocortical insufficiency. Further prospective trials are needed to better define the relationship between fluconazole and adrenocortical insufficiency.

Spontaneous neonatal pneumomediastinum: radiological or clinical diagnosis?

Spontaneous neonatal pneumomediastinum (PNM) is associated with the aspiration of blood or meconium and birth-related trauma and it seems to be more frequent in post-term newborns. It is generally asymptomatic, but it is occasionally accompanied by mild tachypnoea. Only rarely, it requires oxygen therapy or develops into pneumothorax. To evaluate the relationship between the radiological and clinical diagnosis in this uncommon problem, from January 2005 to August 2009, 35 newborns with spontaneous PNM were enrolled in the study. Treatment protocol provides for execution of a chest X-ray, clinical check, SatO(2) and heart rate monitoring. Clinical diagnosis was accomplished particularly early, within the first 24 h of life. Paraphonic and distant tones discovered by cardio-auscultatory exam disappeared within the following 72 h. A total of 28 newborns were asymptomatic (80%); seven were symptomatic (20%); five had transient tachypnoea of the newborn; two developed an RDS, with Silverman score ≥ 3 and required O(2) therapy. It is necessary to affirm the importance of early diagnosis of this condition, carrying out careful monitoring of newborns at risk, to begin timely therapeutic treatments, as oxygen-therapy and to heighten alertness for complications, such as pneumothorax.

Effectiveness of a prematurity-based protocol for management of infants born to mothers with Group B Streptococcus colonisation.

The aim of this study was to validate the efficacy of a protocol for the management of infants born to colonised mothers with Group B Streptococcus (GBS). We studied a cohort of newborns admitted at the A. Gemelli University Hospital between May 2006 and December 2009. A total of 1,108 were newborns of mothers with GBS; 178 were children of mothers with unknown GBS status. Newborns were managed according to the care protocol in use at our division. Infected infants were born to mothers who underwent inadequate intrapartum antibiotic prophylaxis (IAP). No mother with complete IAP had an infected newborn. The incidence of invasive GBS infection in newborns of mothers with GBS was 0.4% and in newborns of mothers with unknown GBS status was 2.2%. Only 17.4% of newborns of mothers with GBS had risk factors. The complete IAP should always be performed regardless of the presence or the absence of risk factors. The care protocol applied offers successful management of the newborns of mothers with GBS, based on the correct execution of IAP, considering as a primary risk factor, the gestational age of < 35 weeks.

Lung recruitment strategies and surfactant in neonatal intensive care unit.

Several studies in the lamb model have shown that hyperinflation of the lungs early in life may cause a blunted response to surfactant with signs of lung injury and any attempt to recruit lung volume in the surfactant deficient preterm infant by large lung inflations at birth should be potentially dangerous. As regards the situation when surfactant is given later, as rescue treatment for established RDS, the evidence for a clinically beneficial effect of a recruitment maneuver is yet insufficient and, hopefully, future studies will gather more data on this aspect.

Post-natal ultrasound morpho-dynamic evaluation of mild fetal hydronephrosis: a new management.

BACKGROUND: Fetal hydronephrosis is the most common anomaly detected on antenatal ultrasound examination, affecting 1-5% pregnancies. AIM: A new management in mild antenatal renal pelvis dilatation (ARPD), using a technique based on both morphological and dynamical evaluation. MATERIALS AND METHODS: Prospective study conducted during a 36-months period in 180 consecutive newborns referred as having mild ARPD. Examinations consisted in a morphological ultra-sound (US) scan evaluating antero-posterior diameter, renal parenchyma, ureteral evidence and pelvis morphology and, subsequently, a dynamic evaluation to analyze any change of the urinary tract during bladder voiding. All children were evaluated both at 3rd day and 1 month after birth. They were divided among those with negative examinations and those with at least one positive scan, trying to discriminate within the latter, children suspected for transient pyelectasis from those suspected for organic pathology. RESULTS: 108 patients had normal US findings both at birth and at 1 month. The remaining 72 babies had at least one abnormal US examination: 54 were suspected for transient pyelectasis, while 18 suspected for organic pathology. At the end of the study, 61 babies (33.9%) had final diagnosis of transient pyelectasis and 11 cases (6.1%) of organic pathology. At one month the dynamic pattern of US findings had the highest negative predictive value, while renal parenchyma evaluation has the highest accuracy. CONCLUSIONS: a dynamic US approach allowed to better select among infants suspected for transient pyelectasis from those suspected for organic pathology, avoiding unnecessary and invasive examinations in healthy babies.

Feasibility of 3D ultrasound to evaluate upper extremity nerves.

PURPOSE: This study investigates the performance of a 3 D Ultrasound (US) system in imaging elbow and wrist nerves. MATERIALS AND METHODS: Twenty healthy volunteers with asymptomatic median, ulnar and radial nerves were prospectively investigated. Bilateral 3DUS scans of the elbows and wrists were acquired by using a commercially available US scanner (18 MHz, AplioXG, Toshiba) and stored as a 3 D volume by a dedicated software (CURE, Robarts Research Institute). Retrospectively, qualitative (image quality, atypical nerve location, findings potentially associated with compression neuropathy) and quantitative (cross-sectional area measurements) evaluations were performed. RESULTS: In all 200 nerves 3DUS was feasible (100%). Image quality was insufficient in 13.5% (25 ulnar nerve elbow, 2 radial nerve) and sonomorphology was not assessable in those nerves. Measurement of cross sectional areas was feasible in all nerves (100%). Median cross-sectional area (range) were: median nerve elbow 7 mm2 (6-9), radial nerve 3 mm2 (1-4), ulnar nerve elbow 8 mm2 (5-11), median nerve wrist 8 mm2 (5-10), and ulnar nerve wrist 4 mm2 (2-6). No significant changes in nerve cross-sectional area along each nerve was found. Ulnar nerve subluxation was found in 2 nerves (6.7%). No anconeus epitrochlearis muscle or osteophytes were found. CONCLUSION: 3DUS is a feasible method for assessing nerves of the upper extremity and has been shown to provide a good overview of the median, ulnar and radial nerve at the elbow and wrist, but is limited for evaluation of the ulnar nerve in the cubital tunnel. This technique enables reliable measurements at different locations along the nerve.

Embolisation of bone metastases from renal cancer.

PURPOSE: This study was done to evaluate embolisation for palliative and/or adjuvant treatment of bone metastases from renal cell carcinoma and discuss the clinical and imaging results. MATERIALS AND METHODS: We retrospectively studied 107 patients with bone metastases from renal cell carcinoma treated from December 2002 to January 2011 with 163 embolisations using N-2-butyl cyanoacrylate (NBCA). Mean tumour diameter before embolisation was 8.8 cm and mean follow-up 4 years. Clinical and imaging effects of treatment were evaluated at follow-up examinations with a pain score scale, analgesic use, hypoattenuating areas, tumour size and ossification. RESULTS: A clinical response was achieved in 157 (96%) and no response in six embolisations of sacroiliac metastases. Mean duration of clinical response was 10 (range 1-12) months. Hypoattenuating areas resembling tumour necrosis were observed in all patients. Variable ossification appeared in 41 patients. Mean maximal tumour diameter after embolisation was 4.0 cm. One patient had intraprocedural tear of the left L3 artery and iliopsoas haemorrhage and was treated with occlusion of the bleeding vessel with NBCA. All patients had variable ischaemic pain that recovered completely within 2-4 days. Postembolisation syndrome was diagnosed after 15 embolisations (9.2%). Transient paraesthesias in the lower extremities were observed after 25 embolisations (25%) of pelvis and sacrum metastatic lesions. CONCLUSIONS: Embolisation with NBCA is recommended as primary or palliative treatment of bone metastases from renal cell carcinoma. Strict adherence to the principles of transcatheter embolisation is important to avoid complications.

Evaluation of cleaning and sterilization of liposuction cannulas after intentional contamination with human fat, Mycobacterium abscessus subspecies bolletii, and Geobacillusstearothermophilus.

BACKGROUND: The complex design of cannulas is a major challenge for reprocessing due to the retention and accumulation of fat residues. AIM: To evaluate the cleaning of liposuction cannulas and the protective effects of the remaining fat residues on Mycobacterium abscessus subspecies bolletii (MASB) and Geobacillus stearothermophilus inactivation during steam sterilization. METHODS: In phase 1, six standard operating procedures were evaluated for cleaning of liposuction cannulas. In phase 2, the sectioned lumens of the liposuction cannulas were contaminated with the largest and smallest volume of human fat found in phase 1, with the addition of MASB. In phase 3, the same volumes of human fat from phase 2 were used to contaminate paper strips containing G. stearothermophilus. FINDINGS: In phase 1 the residual amount of fat ranged from 6 to 52 mg. In phases 2 and 3, the minimum and maximum amounts of fat (6 and 50 mg) protected micro-organisms during steam sterilization at 134 °C for 1.5 and 3 min. CONCLUSION: Effective cleaning and sterilization of liposuction cannulas intentionally contaminated with human fat, MASB and G. stearothermophilus could not be performed.

Tumours of the atlas and axis: a 37-year experience with diagnosis and management.

PURPOSE: This paper presents a single institution's longterm experience regarding the incidence and management of tumours of the atlas and axis and discusses clinical and imaging findings and treatment options. MATERIALS AND METHODS: We searched the registry of the Istituto Ortopedico Rizzoli for patients admitted and treated for tumours of the upper cervical spine. We identified 62 patients over 37 years, from July 1973 to October 2010. There were 39 male and 23 female patients, with a mean age of 39.5 (range 5-77) years. For each patient, we collected data on clinical presentation, imaging and treatment. Mean follow-up was 10 years. RESULTS: Benign bone tumours were diagnosed in 24 (39%) and malignant tumours in 38 (61%) patients. The most common tumours were bone metastases, followed by osteoid osteomas and chordomas. The atlas was involved in six and the axis in 52 patients; in four patients, both the atlas and axis were involved. The most common clinical presentation was pain, torticollis, dysphagia and neurological deficits. Surgical treatment was performed in 35 patients and conservative treatment, including intralesional methylprednisolone injections and halo-vest immobilisation with or without radiation therapy, chemotherapy or embolisation, in the remaining patients. One patient with osteoblastoma of the atlas had local recurrence. All patients with metastatic bone disease had local recurrence; four of the eight patients with plasmacytoma progressed to multiple myeloma within 1-4 years. All patients with chordomas had two to four local recurrences. Patients with osteosarcomas and chondrosarcoma died owing to local and distant disease progression. CONCLUSIONS: Bone tumours of the cervical spine are rare. However, they should be kept in mind when examining patients with neck pain or neurological symptoms at the extremities. In most cases, only intralesional surgery can be administered. Combined radiation therapy and chemotherapy is indicated for certain tumour histologies.

Effectiveness of treatment with surfactant in premature infants with respiratory failure and pulmonary infection.

INTRODUCTION: Surfactant inactivation is present in neonatal pneumonia. MATERIALS AND METHODS: One hundred thirty-nine preterm babies with Birth Weight (BW) < or = 1250 grams were studied and subdivided in two groups: RDS Group, with a diagnosis of "simple" RDS (N 80) and RDS with Pneumonia Group, consisting of babies with a diagnosis of RDS and a positive BALF culture in the first 24-48 h of life (N 59). OUTCOMES: Surfactant administration seems less effective in the latter group, because a significantly higher number of infants needed a second dose of surfactant, compared to the patients suffering from RDS alone. (www.actabiomedica.it).

Comparison between two treatment protocols with recombinant human erythropoietin (rHuEpo) in the treatment of late anemia in neonates with Rh-isoimmunization.

OBJECTIVE: [corrected] The Rh-hemolytic disease can lead to a late anemia by hemolytic and hyporigenerative mechanism. We compared the effectiveness of rHuEPO in two care protocols that differ for doses of rHuEPO administrated and for timing of administration. METHODS: A cohort of 14 neonates was investigated. The neonates were treated with two different protocols. Protocol A: a dose of 200 U/kg/day of rHuEpo administered subcutaneously starting from the end of the second week of life; Protocol B: a dose of 400 U/kg/day of rHuEpo administered subcutaneously starting from the end of the first week of life. RESULTS: The hematocrit values in the protocol A group decreased during treatment (32,5% vs 25,2%), whereas the hematocrit value in protocol B group remained almost stable (38,7% vs 42,8%). The mean numbers of platelets remained stable in both groups while neutrophils increased in protocol A group and decreased in protocol B (p<0,05). Reticulocyte count increased during treatment in both groups, although only in protocol B group it was statistically significative (p<0,05). CONCLUSIONS: Our results suggest a similar efficacy between the two treatment protocols. Increasing doses of rHuEPO do not seem enhancing their effectiveness and the incidence of side effects.

Evaluation of intersession 3D-TRUS to 3D-TRUS image registration for repeat prostate biopsies.

PURPOSE: 3D-TRUS-guided prostate biopsy permits a 3D record of biopsy cores, supporting the planning of targets to resample or avoid during repeat biopsy sessions. Image registration is required in order to map biopsy targets planned on a previous session's 3D-TRUS image into the context of the current session. The authors evaluated the performance of surface- and intensity-based rigid and nonrigid registration algorithms for this task using a clinically motivated success criterion of a maximum 2.5 mm target registration error (TRE). METHODS: The authors collected two 3D-TRUS images for each of 13 patients, where each image was collected in a separate biopsy session, and the sessions were 1 week apart. The authors tested the iterative closest point and thin-plate spline surface-based registration methods, and the block matching and B-spline intensity-based methods. Manually marked intrinsic fiducials (calcifications) were used to calculate a TRE for each of the tested methods. In addition, error ellipsoids, anisotropy, and variability due to image segmentation were analyzed. All analysis was performed separately for the peripheral zone since this area harbors up to 80% of all prostate cancer. RESULTS: Only the intensity-based nonrigid registration method met the success criterion for both the whole gland and the peripheral zone. Segmentation was a substantial contributor to registration error variability for the surface-based methods, and the surface-based methods resulted in greater error volumes and anisotropy. CONCLUSIONS: Intensity-based rigid registration is clinically sufficient to register regions outside the peripheral zone, but nonrigid registration is required in order to register the peripheral zone with clinically needed accuracy. The clinical advantage of using nonrigid registration is questionable since the difference between the RMS TREs for rigid and nonrigid intensity-based registration could be considered to be small (0.3 mm) and is statistically significant. If the added clinical value in performing a nonrigid registration is insufficient given the additional time required for this computation, rigid registration alone may be suitable.

Urinary aldosterone excretion and electrolytic balance in response to chronic diuretic therapy in very low-birth weight infants.

BACKGROUND: It has been reported that the reninangiotensin- aldosterone system of healthy newborn infants and pre-term infants responds to acute furosemide challenge. OBJECTIVE: To assess urinary aldosterone excretion (UAE) and electrolytic balance in very low-birth weight (VLBW) infants who received chronic therapy with furosemide and to compare them with those of infants who did not receive diuretic therapy. METHODS: Infants with birth weight <1500 g were considered eligible for this prospective observational study. On the 10th day of life, infants enrolled were divided in 2 groups on the basis of our predictive score for chronic lung disease (CLD): group 1, with positive score, received furosemide and group 2, with negative score, did not receive diuretic therapy. Urinary aldosterone and electrolytes excretion, electrolytes intakes and clearance of creatinine were investigated before the beginning of the treatment and then weekly until discharge in both groups, and results were compared. RESULTS: Thirty infants were studied: 15 received long-term furosemide and 15 did not. UAE progressively increased in infants who received furosemide whereas remained unchanged in infants who did not receive treatment. UAE was greater in group 1 than in group 2 after 3 weeks of diuretic treatment, reaching statistical significance after 4 weeks of treatment. CONCLUSIONS: In VLBW infants, chronic therapy with furosemide leads to a progressive increase in UAE that may potentially limit the diuretic effect of long-term use of furosemide in the management of CLD.

Suspected transmission of tuberculosis in a maternity ward from a smear-positive nurse: preliminary results of clinical evaluations and testing of neonates potentially exposed, Rome, Italy, 1 January to 28 July 2011.

We report preventive measures adopted after tuberculosis(TB) transmission from a nurse to a newborn assessed in late July 2011. All exposed neonates born between January and July 2011 were clinically evaluated and tested by QuantiFERON TB gold in-tube; newborns testing positive were referred for prophylaxis.Of 1,340 newborns, 118 (9%) tested positive and no other active cases of TB were found. Active surveillance for TB will be continued over the next three years for all those exposed.

US-guided therapy of calcific tendinopathy: clinical and radiological outcome assessment in shoulder and non-shoulder tendons.

PURPOSE: To analyze the effectiveness and complication rate of ultrasound (US)-guided perforation and lavage using a two-needle technique with 16 - 18 G needles in the treatment of patients with calcific tendinopathy in the shoulder, elbow, hip, and knee by radiological and clinical follow-up. MATERIALS AND METHODS: A retrospective chart review was performed and 40 patients (13 male, 27 female; mean age, 53.5 years; range 24 -74 years) were identified as having received US-guided perforation and lavage due to symptomatic calcific tendinopathy of the rotator cuff tendons, triceps, extensor and flexor tendons at the elbow, rectus femoris tendon and patellar tendons. The radiographic outcome was assessed by comparison of the size and quality of the calcification before and 6 weeks after the procedure. On US images, the quality of the acoustic shadow was assessed, together with other alterations of the tendon and surrounding tissue. Patients were interviewed by telephone to assess the clinical outcome regarding pre-treatment and post-treatment pain and tendon function. RESULTS: 34 shoulder tendons and 6 non-shoulder tendons were identified. The mean calcium reduction was 39.9 mm(2) (range, 0 - 215; p < 0.001), while 80 % of patient showed a resolution of more than 60 % resulting in good clinical improvement. A very low complication rate was found (1 partial tear). CONCLUSION: The US-guided perforation and lavage technique is an effective and safe treatment for rotator cuff calcifications as well as for other body tendons. Although the two-needle technique and large needles were used in this study, a very low complication rate was detected.

Front crawl stroke in swimming: Phase durations and self-similarity.

Human movements, such as walking and running, are able to generate rhythmic motor patterns, with the consequent appearance of hidden time-harmonic structures. Such harmonic structures are represented (at comfortable speed) by the occurrence of the golden ratio as ratio of durations of specific walking and running gait sub-phases. Preliminary experimental evidences suggest that front crawl swimming may behave, under this point of view, like walking and running. This paper aims to demonstrate that a mathematical connection between the golden ratio and the front crawl swimming stroke actually exists, at a pace that plays the role of the comfortable speed in walking and running. Generalized Fibonacci sequences are used to this purpose. They rely on the durations of aggregate phases of the front crawl swimming stroke with a clear physical meaning, while characterizing self-similarity of front crawl strokes in its simple nature and enhanced (stronger) variant. Experimental data on front crawl swimmers illustrate the theoretical derivations, suggesting that the pace playing the role of the comfortable speed in walking and running is the middle/long-distance one, while showing that the self-similarity level increases with the swimming technique and the enhanced self-similarity is associated with the performance of top-level swimmers.

Assessment of image registration accuracy in three-dimensional transrectal ultrasound guided prostate biopsy.

PURPOSE: Prostate biopsy, performed using two-dimensional (2D) transrectal ultrasound (TRUS) guidance, is the clinical standard for a definitive diagnosis of prostate cancer. Histological analysis of the biopsies can reveal cancerous, noncancerous, or suspicious, possibly precancerous, tissue. During subsequent biopsy sessions, noncancerous regions should be avoided, and suspicious regions should be precisely rebiopsied, requiring accurate needle guidance. It is challenging to precisely guide a needle using 2D TRUS due to the limited anatomic information provided, and a three-dimensional (3D) record of biopsy locations for use in subsequent biopsy procedures cannot be collected. Our tracked, 3D TRUS-guided prostate biopsy system provides additional anatomic context and permits a 3D record of biopsies. However, targets determined based on a previous biopsy procedure must be transformed during the procedure to compensate for intraprocedure prostate shifting due to patient motion and prostate deformation due to transducer probe pressure. Thus, registration is a critically important step required to determine these transformations so that correspondence is maintained between the prebiopsied image and the real-time image. Registration must not only be performed accurately, but also quickly, since correction for prostate motion and deformation must be carried out during the biopsy procedure. The authors evaluated the accuracy, variability, and speed of several surface-based and image-based intrasession 3D-to-3D TRUS image registration techniques, for both rigid and nonrigid cases, to find the required transformations. METHODS: Our surface-based rigid and nonrigid registrations of the prostate were performed using the iterative-closest-point algorithm and a thin-plate spline algorithm, respectively. For image-based rigid registration, the authors used a block matching approach, and for nonrigid registration, the authors define the moving image deformation using a regular, 3D grid of B-spline control points. The authors measured the target registration error (TRE) as the postregistration misalignment of 60 manually marked, corresponding intrinsic fiducials. The authors also measured the fiducial localization error (FLE), the effect of segmentation variability, and the effect of fiducial distance from the transducer probe tip. Lastly, the authors performed 3D principal component analysis (PCA) on the x, y, and z components of the TREs to examine the 95% confidence ellipsoids describing the errors for each registration method. RESULTS: Using surface-based registration, the authors found mean TREs of 2.13 +/- 0.80 and 2.09 +/- 0.77 mm for rigid and nonrigid techniques, respectively. Using image-based rigid and non-rigid registration, the authors found mean TREs of 1.74 +/- 0.84 and 1.50 +/- 0.83 mm, respectively. Our FLE was 0.21 mm and did not dominate the overall TRE. However, segmentation variability contributed substantially approximately50%) to the TRE of the surface-based techniques. PCA showed that the 95% confidence ellipsoid encompassing fiducial distances between the source and target registra- tion images was reduced from 3.05 to 0.14 cm3, and 0.05 cm3 for the surface-based and image-based techniques, respectively. The run times for both registration methods were comparable at less than 60 s. CONCLUSIONS: Our results compare favorably with a clinical need for a TRE of less than 2.5 mm, and suggest that image-based registration is superior to surface-based registration for 3D TRUS-guided prostate biopsies, since it does not require segmentation.